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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0706.3414 | Douglas Smith | Rae M. Robertson and Douglas E. Smith | Direct measurement of the intermolecular forces confining a single
molecule in an entangled polymer solution | 11 pages, 3 figures | null | 10.1103/PhysRevLett.99.126001 | null | cond-mat.soft | null | We use optical tweezers to directly measure the intermolecular forces acting
on a single polymer imposed by surrounding entangled polymers (115 kbp DNA, 1
mg/ml). A tube-like confining field was measured in accord with the key
assumption of reptation models. A time-dependent harmonic potential opposed
transverse displacement, in accord with recent simulation findings. A tube
radius of 0.8 microns was determined, close to the predicted value (0.5
microns). Three relaxation modes (~0.4, 5 and 30 s) were measured following
transverse displacement, consistent with predicted relaxation mechanisms.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 16:50:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Robertson",
"Rae M.",
""
],
[
"Smith",
"Douglas E.",
""
]
] |
0706.3415 | Jeffrey Humpherys | Nicola Costanzino, Jeffrey Humpherys, Toan Nguyen, Kevin Zumbrun | Spectral stability of noncharacteristic isentropic Navier-Stokes
boundary layers | null | null | 10.1007/s00205-008-0153-1 | null | math.AP | null | Building on work of Barker, Humpherys, Lafitte, Rudd, and Zumbrun in the
shock wave case, we study stability of compressive, or "shock-like", boundary
layers of the isentropic compressible Navier-Stokes equations with gamma-law
pressure by a combination of asymptotic ODE estimates and numerical Evans
function computations. Our results indicate stability for gamma in the interval
[1, 3] for all compressive boundary-layers, independent of amplitude, save for
inflow layers in the characteristic limit (not treated). Expansive inflow
boundary-layers have been shown to be stable for all amplitudes by Matsumura
and Nishihara using energy estimates. Besides the parameter of amplitude
appearing in the shock case, the boundary-layer case features an additional
parameter measuring displacement of the background profile, which greatly
complicates the resulting case structure. Moreover, inflow boundary layers turn
out to have quite delicate stability in both large-displacement and
large-amplitude limits, necessitating the additional use of a mod-two stability
index studied earlier by Serre and Zumbrun in order to decide stability.
| [
{
"version": "v1",
"created": "Fri, 22 Jun 2007 22:45:05 GMT"
}
] | 2017-06-12T00:00:00 | [
[
"Costanzino",
"Nicola",
""
],
[
"Humpherys",
"Jeffrey",
""
],
[
"Nguyen",
"Toan",
""
],
[
"Zumbrun",
"Kevin",
""
]
] |
0706.3416 | Jeffrey H. Shapiro | Saikat Guha, Jeffrey H. Shapiro, and Baris I. Erkmen | Classical capacity of bosonic broadcast communication and a new minimum
output entropy conjecture | 13 pages, 7 figures | Phys. Rev. A 76, 032303 (2007) | 10.1103/PhysRevA.76.032303 | null | quant-ph | null | Previous work on the classical information capacities of bosonic channels has
established the capacity of the single-user pure-loss channel, bounded the
capacity of the single-user thermal-noise channel, and bounded the capacity
region of the multiple-access channel. The latter is a multi-user scenario in
which several transmitters seek to simultaneously and independently communicate
to a single receiver. We study the capacity region of the bosonic broadcast
channel, in which a single transmitter seeks to simultaneously and
independently communicate to two different receivers. It is known that the
tightest available lower bound on the capacity of the single-user thermal-noise
channel is that channel's capacity if, as conjectured, the minimum von Neumann
entropy at the output of a bosonic channel with additive thermal noise occurs
for coherent-state inputs. Evidence in support of this minimum output entropy
conjecture has been accumulated, but a rigorous proof has not been obtained. In
this paper, we propose a new minimum output entropy conjecture that, if proved
to be correct, will establish that the capacity region of the bosonic broadcast
channel equals the inner bound achieved using a coherent-state encoding and
optimum detection. We provide some evidence that supports this new conjecture,
but again a full proof is not available.
| [
{
"version": "v1",
"created": "Fri, 22 Jun 2007 23:41:42 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Guha",
"Saikat",
""
],
[
"Shapiro",
"Jeffrey H.",
""
],
[
"Erkmen",
"Baris I.",
""
]
] |
0706.3417 | Chih-Chun Chien | Chih-Chun Chien, Yan He, Qijin Chen and K. Levin | Superfuid-insulator transitions at non-integer filling in optical
lattices of fermionic atoms | 4 pages, 3 figures, submitted to Phys. Rev. A | Phys. Rev. A 77, 011601(R) (2008) | 10.1103/PhysRevA.77.011601 | null | cond-mat.other cond-mat.quant-gas cond-mat.str-el cond-mat.supr-con | null | We determine the superfluid transition temperatures $T_c$ and the ground
states of the attractive Hubbard model and find new insulating phases
associated with non-integer filling at sufficiently strong pairing attraction
$|U|$. These states, distinct from band and Mott insulating phases, derive from
pair localization; pair hopping at large $|U|$ and high densities is impeded by
inter-site, inter-pair repulsive interactions. The best way to detect the
breakdown of superfluidity is using fermionic optical lattices which should
reveal new forms of ``bosonic'' order, reflecting ground state pairing without
condensation.
| [
{
"version": "v1",
"created": "Fri, 22 Jun 2007 22:54:40 GMT"
},
{
"version": "v2",
"created": "Thu, 13 Sep 2007 18:10:31 GMT"
}
] | 2011-09-13T00:00:00 | [
[
"Chien",
"Chih-Chun",
""
],
[
"He",
"Yan",
""
],
[
"Chen",
"Qijin",
""
],
[
"Levin",
"K.",
""
]
] |
0706.3418 | Dagim Tilahun | Dagim Tilahun, Gregory A. Fiete | Tunneling Density of States, Pair Correlation, and Josephson Current in
Spin-Incoherent Luttinger Liquid-Superconductor Hybrid Systems | 5 pages, 2 figures, definition of the spin-incoherent luttinger
regime clarified, references 3 and 10 updated | Phys. Rev. B 77, 140505(R) (2008) | 10.1103/PhysRevB.77.140505 | NSF-KITP-07-150 | cond-mat.str-el cond-mat.mes-hall | null | We study a hybrid system consisting of a spin-incoherent Luttinger liquid
adjoined at one or both ends to a superconductor. We find the tunneling density
of states diverges at low energies and exhibits a universal frequency
dependence independent of the strength of the interactions in the system. We
show that in spite of exponentially decaying pair correlations with distance
into the spin-incoherent Luttinger liquid, the Josephson current remains
robust. Compared to the zero temperature Luttinger liquid case there is a
factor of 2 reduction in the critical current and a halving of the period in
the phase difference between the superconductors. Our results open the way for
a new class of experiments in the spin-incoherent regime of one dimensional
systems.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 17:02:27 GMT"
},
{
"version": "v2",
"created": "Fri, 10 Aug 2007 22:44:08 GMT"
}
] | 2008-04-26T00:00:00 | [
[
"Tilahun",
"Dagim",
""
],
[
"Fiete",
"Gregory A.",
""
]
] |
0706.3419 | Giovanni Cantatore | E. Zavattini (Deceased January 9, 2007), G. Zavattini, G. Raiteri, G.
Ruoso, E. Polacco, E. Milotti, V. Lozza, M. Karuza, U. Gastaldi, G. Di
Domenico, F. Della Valle, R. Cimino, S. Carusotto, G. Cantatore, M. Bregant
(PVLAS Collaboration) | New PVLAS results and limits on magnetically induced optical rotation
and ellipticity in vacuum | 25 pages, 7 figures Main changes rel. to v.2: minor changes to
abstract, replaced Figures 4,5,6, corrected typographical errors. Paper
submitted to Physical Review D | Phys.Rev.D77:032006,2008 | 10.1103/PhysRevD.77.032006 | null | hep-ex | null | IIn 2006 the PVLAS collaboration reported the observation of an optical
rotation generated in vacuum by a magnetic field. To further check against
possible instrumental artifacts several upgrades to the PVLAS apparatus have
been made during the last year. Two data taking runs, at the wavelength of 1064
nm, have been performed in the new configuration with magnetic field strengths
of 2.3 T and 5 T. The 2.3 T field value was chosen in order to avoid stray
fields. The new observations do not show the presence of a rotation signal down
to the levels of $1.2\cdot 10^{-8}$ rad at 5 T and $1.0\cdot 10^{-8}$ rad at
2.3 T (at 95% c.l.) with 45000 passes in the magnetic field zone. In the same
conditions no ellipticity signal was detected down to $1.4\cdot 10^{-8}$ at 2.3
T (at 95% c.l.), whereas at 5 T a signal is still present. The physical nature
of this ellipticity as due to an effect depending on $B^2$ can be excluded by
the measurement at 2.3 T. These new results completely exclude the previously
published magnetically induced vacuum dichroism results, indicating that they
were instrumental artifacts. These new results therefore also exclude the
particle interpretation of the previous PVLAS results as due to a spin zero
boson. The background ellipticity at 2.3 T can be used to determine a new limit
on the total photon-photon scattering cross section of $\sigma_{\gamma\gamma} <
4.5 \cdot10^{-34}$ barn at 95% c.l..
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 07:51:58 GMT"
},
{
"version": "v2",
"created": "Tue, 25 Sep 2007 22:25:59 GMT"
},
{
"version": "v3",
"created": "Thu, 22 Nov 2007 12:27:48 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Zavattini",
"E.",
"",
"Deceased January 9, 2007"
],
[
"Zavattini",
"G.",
"",
"PVLAS Collaboration"
],
[
"Raiteri",
"G.",
"",
"PVLAS Collaboration"
],
[
"Ruoso",
"G.",
"",
"PVLAS Collaboration"
],
[
"Polacco",
"E.",
"",
"PVLAS Collaboration"
],
[
"Milotti",
"E.",
"",
"PVLAS Collaboration"
],
[
"Lozza",
"V.",
"",
"PVLAS Collaboration"
],
[
"Karuza",
"M.",
"",
"PVLAS Collaboration"
],
[
"Gastaldi",
"U.",
"",
"PVLAS Collaboration"
],
[
"Di Domenico",
"G.",
"",
"PVLAS Collaboration"
],
[
"Della Valle",
"F.",
"",
"PVLAS Collaboration"
],
[
"Cimino",
"R.",
"",
"PVLAS Collaboration"
],
[
"Carusotto",
"S.",
"",
"PVLAS Collaboration"
],
[
"Cantatore",
"G.",
"",
"PVLAS Collaboration"
],
[
"Bregant",
"M.",
"",
"PVLAS Collaboration"
]
] |
0706.3420 | Marcelo Grynberg | M. D. Grynberg | Non-universal dynamics of dimer growing interfaces | 11 pages, 7 figures. v2 with some slight corrections | Phys. Rev. E 76, 031605 (2007) | 10.1103/PhysRevE.76.031605 | null | cond-mat.stat-mech cond-mat.soft | null | A finite temperature version of body-centered solid-on-solid growth models
involving attachment and detachment of dimers is discussed in 1+1 dimensions.
The dynamic exponent of the growing interface is studied numerically via the
spectrum gap of the underlying evolution operator. The finite size scaling of
the latter is found to be affected by a standard surface tension term on which
the growth rates depend. This non-universal aspect is also corroborated by the
growth behavior observed in large scale simulations. By contrast, the
roughening exponent remains robust over wide temperature ranges.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 00:02:58 GMT"
},
{
"version": "v2",
"created": "Thu, 27 Sep 2007 03:31:08 GMT"
}
] | 2007-09-27T00:00:00 | [
[
"Grynberg",
"M. D.",
""
]
] |
0706.3421 | Peter Jonker | Peter G. Jonker, Daniel Steeghs, Deepto Chakrabarty, Adrienne M. Juett | The cold neutron star in the soft X-ray transient 1H 1905+000 | 5 pages, 3 figures, accepted for publication in ApJ Letters | null | 10.1086/521079 | null | astro-ph | null | We report on our analysis of 300 ks of Chandra observations of the neutron
star soft X-ray transient 1H1905+000 in quiescence. We do not detect the source
down to a 95% confidence unabsorbed flux upper limit of 2E-16 erg cm-2 s-1 in
the 0.5-10 keV energy range for an assumed Gamma=2 power law spectral model. A
limit of 1.4E-16 erg cm-2 s-1 is derived if we assume that the spectrum of
1H1905+000 in quiescence is described well with a black body of temperature of
0.2 keV. For the upper limit to the source distance of 10 kpc this yields a
0.5-10 keV luminosity limit of 2.4E30 / 1.7E30 erg/s for the abovementioned
power law or black body spectrum, respectively. This luminosity limit is lower
than the luminosity of A0620-00, the weakest black hole soft X-ray transient in
quiescence reported so far. Together with the uncertainties in relating the
mass transfer and mass accretion rates we come to the conclusion that the claim
that there is evidence for the presence of a black hole event horizon on the
basis of a lower quiescent luminosity for black holes than for neutron stars is
unproven. We also briefly discuss the implications of the low quiescent
luminosity of 1H1905+000 for the neutron star equation of state. Using deep
Magellan images of the field of 1H1905+000 obtained at excellent observing
conditions we do not detect the quiescent counterpart at the position of the
outburst optical counterpart down to a magnitude limit of i'>25.3. This can be
converted to a limit on the absolute magnitude of the counterpart of I>9.6
which implies that the counterpart can only be a brown or a white dwarf.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 01:15:43 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Jonker",
"Peter G.",
""
],
[
"Steeghs",
"Daniel",
""
],
[
"Chakrabarty",
"Deepto",
""
],
[
"Juett",
"Adrienne M.",
""
]
] |
0706.3422 | Florian Conrady | Florian Conrady (Penn State U.) | Dual representation of Polyakov loop in 3d SU(2) lattice Yang-Mills
theory | 17 pages, 6 figures; minor changes | null | null | IGPG-07/6-7 | hep-lat | null | We consider the expectation value of a Polyakov loop in 3d SU(2) lattice
Yang--Mills theory and transform it to the dual representation in terms of sums
over spins. The spin dependence of the amplitudes is computed explicitly by a
graphical method. We also determine the asymptotic (large spin) limit of the
amplitude factors.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 21:43:10 GMT"
},
{
"version": "v2",
"created": "Mon, 15 Oct 2007 01:35:09 GMT"
}
] | 2007-10-15T00:00:00 | [
[
"Conrady",
"Florian",
"",
"Penn State U."
]
] |
0706.3423 | Florian Conrady | Florian Conrady (Penn State U.) and Igor Khavkine (Western Ontario U.) | An exact string representation of 3d SU(2) lattice Yang--Mills theory | 12 pages, 7 figures | null | null | IGPG-07/6-8 | hep-th hep-lat | null | We show that 3d SU(2) lattice Yang--Mills theory can be cast in the form of
an exact string representation. The derivation starts from the exact dual (or
spin foam) representation of the lattice gauge theory. We prove that every dual
configuration (or spin foam) can be equivalently described as a self--avoiding
worldsheet of strings on a framing of the lattice. Using this correspondence,
we translate the partition function into a sum over closed worldsheets that are
weighted with explicit amplitudes. The expectation value of two Polyakov loops
with spin j becomes a sum over worldsheets that are bounded by 2j strings along
a framing of the loops.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 14:24:49 GMT"
}
] | 2007-07-03T00:00:00 | [
[
"Conrady",
"Florian",
"",
"Penn State U."
],
[
"Khavkine",
"Igor",
"",
"Western Ontario U."
]
] |
0706.3424 | Ryan Mallery | Ryan P. Mallery, R. Michael Rich, Samir Salim, Todd Small, Stephane
Charlot, Mark Seibert, Ted Wyder, Tom A. Barlow, Karl Forster, Peter G.
Friedman, D. Christopher Martin, Patrick Morissey, Susan G. Neff, David
Schiminovivich, Luciana Bianchi, Jose Donas, Timothy M. Heckman, Young-Wook
Lee, Barry F. Madore, Bruno Milliard, Alex S. Szalay, Barry Y. Welsh, Suk
Young Yi | Keck/Deimos Spectroscopy of a GALEX UV Selecte Sample from the Medium
Imaging Survey | 19 pages 11 figures, 2 tables, Accepted ot ApJ GALEX Special Issue | null | 10.1086/516638 | null | astro-ph | null | We report results from a pilot program to obtain spectroscopy for objects
detected in the Galaxy Evolution Explorer (GALEX) Medium Imaging Survey (MIS).
Our study examines the properties of galaxies detected by GALEX fainter than
the Sloan Digital Sky Survey (SDSS) spectroscopic survey. This is the first
study to extend the techinques of Salim et al. 2005 to estimate stellar masses,
star formation rates (SFR) and the b (star formation history) parameter for
star-forming galaxies out to z~0.7. We obtain redshifts for 50 GALEX MIS
sources reaching NUV=23.9 (AB mag), having counterparts in the SDSS Data
Release 4 (DR4). Of our sample, 43 are starforming galaxies with z<0.7, 3 have
emission line ratios indicative of AGN with z<0.7, and 4 objects with z~1 are
QSOs, 3 of which are not previously cataloged. We compare our sample to a much
larger sample of ~50,000 matched GALEX/SDSS galaxies with SDSS spectroscopy;
while our survey is shallow, the optical counterparts to our sources reach ~3
magnitudes fainter in SDSS r magnitude than the SDSS spectroscopic sample. We
use emission line diagnostics for the galaxies to determine that the sample
contains mostly star-forming galaxies. The galaxies in the sample populate the
blue sequence in the NUV-r vs M_r color-magnitude diagram. Our sample has SFRs,
luminosities, and velocity dispersions that are similar to the samples of faint
compact blue galaxies studied previously in the same redshift range by Koo et.
al 1995, Guzman et. al 1996 & Phillips et. al 1997. However, our sample is ~2
mag fainter in surface brightness than the compact blue galaxies. We find that
the star-formation histories for a majority of the galaxies are consistent with
a recent starburst within the last 100 Myr.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 02:01:25 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Mallery",
"Ryan P.",
""
],
[
"Rich",
"R. Michael",
""
],
[
"Salim",
"Samir",
""
],
[
"Small",
"Todd",
""
],
[
"Charlot",
"Stephane",
""
],
[
"Seibert",
"Mark",
""
],
[
"Wyder",
"Ted",
""
],
[
"Barlow",
"Tom A.",
""
],
[
"Forster",
"Karl",
""
],
[
"Friedman",
"Peter G.",
""
],
[
"Martin",
"D. Christopher",
""
],
[
"Morissey",
"Patrick",
""
],
[
"Neff",
"Susan G.",
""
],
[
"Schiminovivich",
"David",
""
],
[
"Bianchi",
"Luciana",
""
],
[
"Donas",
"Jose",
""
],
[
"Heckman",
"Timothy M.",
""
],
[
"Lee",
"Young-Wook",
""
],
[
"Madore",
"Barry F.",
""
],
[
"Milliard",
"Bruno",
""
],
[
"Szalay",
"Alex S.",
""
],
[
"Welsh",
"Barry Y.",
""
],
[
"Yi",
"Suk Young",
""
]
] |
0706.3425 | Peter Wong | Daciberg Gon\c{c}alves and Peter Wong | Twisted conjugacy classes in nilpotent groups | 22 pages; section 6 has been moved to section 2 and minor
modification has been made on exposition; to be published in Crelle J | J. Reine Angew. Math. 633 (2009), 11--27 | null | null | math.GR math.AT | null | A group is said to have the $R_\infty$ property if every automorphism has an
infinite number of twisted conjugacy classes. We study the question whether $G$
has the $R_\infty$ property when $G$ is a finitely generated torsion-free
nilpotent group. As a consequence, we show that for every positive integer
$n\ge 5$, there is a compact nilmanifold of dimension $n$ on which every
homeomorphism is isotopic to a fixed point free homeomorphism. As a by-product,
we give a purely group theoretic proof that the free group on two generators
has the $R_\infty$ property. The $R_{\infty}$ property for virtually abelian
and for $\mathcal C$-nilpotent groups are also discussed.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 01:56:53 GMT"
},
{
"version": "v2",
"created": "Mon, 24 Mar 2008 16:18:43 GMT"
}
] | 2011-05-11T00:00:00 | [
[
"Gonçalves",
"Daciberg",
""
],
[
"Wong",
"Peter",
""
]
] |
0706.3426 | Bo Wang | Bo Wang, Xiangcun Meng, Xiaofeng Wang, Zhanwen Han | Distribution of $^{56}$Ni Yields of Type Ia Supernovae and its
Implication for Progenitors | 11 pages, 7 figures | Chin.J.Astron.Astrophys.8:71-80,2008 | 10.1088/1009-9271/8/1/07 | null | astro-ph | null | The amount of $^{56}$Ni produced in type Ia supernova (SN Ia) explosion is
probably the most important physical parameter underlying the observed
correlation of SN Ia luminosities with their light curves. Based on an
empirical relation between the $^{56}$Ni mass and the light curve parameter
$\triangle m_{15}$, we obtained rough estimates of the $^{56}$Ni mass for a
large sample of nearby SNe Ia with the aim of exploring the diversity in SN Ia.
We found that the derived $^{56}$Ni masses for different SNe Ia could vary by a
factor of ten (e.g., $M_{\rm Ni}=0.1 - 1.3$ $M_{\odot}$), which cannot be
explained in terms of the standard Chandrasekhar-mass model (with a $^{56}$Ni
mass production of 0.4 -- 0.8 $M_{\odot}$). Different explosion and/or
progenitor models are clearly required for various SNe Ia, in particular, for
those extremely nickel-poor and nickel-rich producers. The nickel-rich (with
$M_{\rm Ni}$ $>$ 0.8 $M_{\odot}$) SNe Ia are very luminous and may have massive
progenitors exceeding the Chandrasekhar-mass limit since extra progenitor fuel
is required to produce more $^{56}$Ni to power the light curve. This is also
consistent with the finding that the intrinsically bright SNe Ia prefer to
occur in stellar environments of young and massive stars. For example, 75% SNe
Ia in spirals have $\Delta m_{15} < 1.2$ while this ratio is only 18% in E/S0
galaxies. On the other hand, the nickel-poor SNe Ia (with $M_{\rm Ni}$ $<$ 0.2
$M_{\odot}$) may invoke the sub-Chandrasekhar model, as most of them were found
in early-type E/S0 galaxies dominated by the older and low-mass stellar
populations. This indicates that SNe Ia in spiral and E/S0 galaxies have
progenitors of different properties.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 03:28:06 GMT"
},
{
"version": "v2",
"created": "Wed, 27 Feb 2008 12:05:03 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wang",
"Bo",
""
],
[
"Meng",
"Xiangcun",
""
],
[
"Wang",
"Xiaofeng",
""
],
[
"Han",
"Zhanwen",
""
]
] |
0706.3427 | Dmitri Starodub | D. Starodub (1), P. Rez (1), G. Hembree (1), M. Howells (2), D.
Shapiro (2), H. N. Chapman (3), P. Fromme (1), K. Schmidt (1), U. Weierstall
(1), R. B. Doak (1) and J. C. H. Spence (1) ((1) Arizona State University,
(2) Lawrence Berkeley National Laboratory, (3) Lawrence Livermore National
Laboratory) | Dose, exposure time, and resolution in Serial X-ray Crystallography | 19 pages, 7 figures, 1 table | null | null | null | physics.optics physics.bio-ph | null | The resolution of X-ray diffraction microscopy is limited by the maximum dose
that can be delivered prior to sample damage. In the proposed Serial
Crystallography method, the damage problem is addressed by distributing the
total dose over many identical hydrated macromolecules running continuously in
a single-file train across a continuous X-ray beam, and resolution is then
limited only by the available molecular and X-ray fluxes and molecular
alignment. Orientation of the diffracting molecules is achieved by laser
alignment. We evaluate the incident X-ray fluence (energy/area) required to
obtain a given resolution from (1) an analytical model, giving the count rate
at the maximum scattering angle for a model protein, (2) explicit simulation of
diffraction patterns for a GroEL-GroES protein complex, and (3) the frequency
cut off of the transfer function following iterative solution of the phase
problem, and reconstruction of an electron density map in the projection
approximation. These calculations include counting shot noise and multiple
starts of the phasing algorithm. The results indicate counting time and the
number of proteins needed within the beam at any instant for a given resolution
and X-ray flux. We confirm an inverse fourth power dependence of exposure time
on resolution, with important implications for all coherent X-ray imaging. We
find that multiple single-file protein beams will be needed for sub-nanometer
resolution on current third generation synchrotrons, but not on fourth
generation designs, where reconstruction of secondary protein structure at a
resolution of 0.7 nm should be possible with short exposures.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 03:40:13 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Starodub",
"D.",
""
],
[
"Rez",
"P.",
""
],
[
"Hembree",
"G.",
""
],
[
"Howells",
"M.",
""
],
[
"Shapiro",
"D.",
""
],
[
"Chapman",
"H. N.",
""
],
[
"Fromme",
"P.",
""
],
[
"Schmidt",
"K.",
""
],
[
"Weierstall",
"U.",
""
],
[
"Doak",
"R. B.",
""
],
[
"Spence",
"J. C. H.",
""
]
] |
0706.3428 | Sourendu Gupta | R. S. Bhalerao and Sourendu Gupta | Aspects of causal viscous hydrodynamics | 27 pages, 17 figures, references added, minor changes, version to
appear in Phys. Rev. (C) | Phys.Rev.C77:014902,2008 | 10.1103/PhysRevC.77.014902 | TIFR/TH/07-11 | nucl-th hep-ph nucl-ex | null | We investigate the phenomenology of freely expanding fluids, with different
material properties, evolving through the Israel-Stewart (IS) causal viscous
hydrodynamics, and compare our results with those obtained in the relativistic
Eckart-Landau-Navier-Stokes (ELNS) acausal viscous hydrodynamics. Through the
analysis of scaling invariants we give a definition of thermalization time
which can be self-consistently determined in viscous hydrodynamics. Next we
construct the solutions for one-dimensional boost-invariant flows. Expansion of
viscous fluids is slower than that of one-dimensional ideal fluids, resulting
in entropy production. At late times, these flows are reasonably well
approximated by solutions obtained in ELNS hydrodynamics. Estimates of initial
energy densities from observed final values are strongly dependent on the
dynamics one chooses. For the same material, and the same final state, IS
hydrodynamics gives the smallest initial energy density. We also study
fluctuations about these one-dimensional boost-invariant backgrounds; they are
damped in ELNS hydrodynamics but can become sound waves in IS hydrodynamics.
The difference is obvious in power spectra due to clear signals of
wave-interference in IS hydrodynamics, which is completely absent in ELNS
dynamics.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 05:25:57 GMT"
},
{
"version": "v2",
"created": "Sun, 1 Jul 2007 06:36:18 GMT"
},
{
"version": "v3",
"created": "Wed, 12 Dec 2007 14:18:18 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bhalerao",
"R. S.",
""
],
[
"Gupta",
"Sourendu",
""
]
] |
0706.3429 | Roland M. Crocker | Roland M. Crocker, David Jones, David R. Ballantyne, and Fulvio Melia | Radio Synchrotron Emission from Secondary Leptons in the Vicinity of Sgr
A* | 11 pages, 2 figures. Two references missing from published version
added and acknowledgements extended | ApJ Letters 664, 95 (2007) | 10.1086/520931 | null | astro-ph | null | A point-like source of ~TeV gamma-rays has recently been seen towards the
Galactic center by HESS and other air Cerenkov telescopes. In recent work
(Ballantyne et al. 2007), we demonstrated that these gamma-rays can be
attributed to high-energy protons that (i) are accelerated close to the event
horizon of the central black hole, Sgr A*, (ii) diffuse out to ~pc scales, and
(iii) finally interact to produce gamma-rays. The same hadronic collision
processes will necessarily lead to the creation of electrons and positrons.
Here we calculate the synchrotron emissivity of these secondary leptons in the
same magnetic field configuration through which the initiating protons have
been propagated in our model. We compare this emission with the observed ~GHz
radio spectrum of the inner few pc region which we have assembled from archival
data and new measurements we have made with the Australia Telescope Compact
Array. We find that our model predicts secondary synchrotron emission with a
steep slope consistent with the observations but with an overall normalization
that is too large by a factor of ~ 2. If we further constrain our theoretical
gamma-ray curve to obey the implicit EGRET upper limit on emission from this
region we predict radio emission that is consistent with observations, i.e.,
the hadronic model of gamma ray emission can, simultaneously and without
fine-tuning, also explain essentially all the diffuse radio emission detected
from the inner few pc of the Galaxy.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 05:57:29 GMT"
},
{
"version": "v2",
"created": "Tue, 7 Aug 2007 06:25:47 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Crocker",
"Roland M.",
""
],
[
"Jones",
"David",
""
],
[
"Ballantyne",
"David R.",
""
],
[
"Melia",
"Fulvio",
""
]
] |
0706.3430 | Caleb Lo | Caleb K. Lo, Robert W. Heath Jr. and Sriram Vishwanath | The Impact of Channel Feedback on Opportunistic Relay Selection for
Hybrid-ARQ in Wireless Networks | 30 pages, 9 figures, submitted to the IEEE Transactions on Vehicular
Technology, revised March 2008 | null | 10.1109/TVT.2008.928896 | null | cs.IT math.IT | null | This paper presents a decentralized relay selection protocol for a dense
wireless network and describes channel feedback strategies that improve its
performance. The proposed selection protocol supports hybrid
automatic-repeat-request transmission where relays forward parity information
to the destination in the event of a decoding error. Channel feedback is
employed for refining the relay selection process and for selecting an
appropriate transmission mode in a proposed adaptive modulation transmission
framework. An approximation of the throughput of the proposed adaptive
modulation strategy is presented, and the dependence of the throughput on
system parameters such as the relay contention probability and the adaptive
modulation switching point is illustrated via maximization of this
approximation. Simulations show that the throughput of the proposed selection
strategy is comparable to that yielded by a centralized selection approach that
relies on geographic information.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 06:19:41 GMT"
},
{
"version": "v2",
"created": "Tue, 15 Jan 2008 21:15:03 GMT"
},
{
"version": "v3",
"created": "Tue, 1 Apr 2008 00:02:32 GMT"
}
] | 2016-11-15T00:00:00 | [
[
"Lo",
"Caleb K.",
""
],
[
"Heath",
"Robert W.",
"Jr."
],
[
"Vishwanath",
"Sriram",
""
]
] |
0706.3431 | Amin Rezaeezadeh | Amin Rezaeezadeh | Motion of Hexagonal Pencil on an Inclined Plane | 2 pages | null | null | null | physics.class-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This paper has been withdrawn by the author(s), due a crucial sign error in
Eqn. 1.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 07:08:00 GMT"
},
{
"version": "v2",
"created": "Wed, 28 May 2008 15:34:25 GMT"
},
{
"version": "v3",
"created": "Mon, 23 Feb 2009 20:29:16 GMT"
}
] | 2009-02-23T00:00:00 | [
[
"Rezaeezadeh",
"Amin",
""
]
] |
0706.3432 | Chiyori Urabe | Chiyori Urabe | Fluctuation of the Top Location and Avalanches in the Formation Process
of a Sandpile | 15 pages, 13 figures | null | 10.1143/JPSJ.76.094401 | null | cond-mat.soft | null | We investigate the formation processes of a sandpile using numerical
simulation. We find a new relation between the fluctuation of the motion of the
top and the surface state of a sandpile. The top moves frequently as particles
are fed one by one every time interval T. The time series of the top location
has the power spectrum which obeys a power law, S(f)~f^{\alpha}, and its
exponent \alpha depends on T and the system size w. The surface state is
characterized by two time scales; the lifetime of an avalanche, T_{a}, and the
time required to cause an avalanche, T_{s}. The surface state is fluid-like
when T_{a}~T_{s}, and it is solid-like when T_{a}<<T_{s}. Our numerical results
show that \alpha is a function of T_{s}/T_{a}.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 07:18:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Urabe",
"Chiyori",
""
]
] |
0706.3433 | Mesfin Asfaw | Mesfin Asfaw | Unbinding transitions of multicomponent membranes and strings | 11 figures, 10 pages | null | null | null | cond-mat.soft | null | We present a theory of unbinding transitions for membranes that interact via
short and long receptor/ligand bonds. The detail of unbinding behavior of the
membranes is governed by the binding energies and concentrations of receptors
and ligands. We investigate the unbinding behavior of these membranes with
Monte Carlo simulations and via a comparison with strings. We derive the
scaling laws for strings analytically. The exact analytic results provide
scaling estimate for membranes in the vicinity of the critical point.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 07:52:44 GMT"
},
{
"version": "v2",
"created": "Wed, 2 Apr 2008 02:50:32 GMT"
}
] | 2008-04-02T00:00:00 | [
[
"Asfaw",
"Mesfin",
""
]
] |
0706.3434 | Shuheng Zhou | Avrim Blum, Amin Coja-Oghlan, Alan Frieze, Shuheng Zhou | Separating populations with wide data: A spectral analysis | Published in at http://dx.doi.org/10.1214/08-EJS289 the Electronic
Journal of Statistics (http://www.i-journals.org/ejs/) by the Institute of
Mathematical Statistics (http://www.imstat.org) | Electronic Journal of Statistics 2009, Vol. 3, 76-113 | 10.1214/08-EJS289 | IMS-EJS-EJS_2008_289 | stat.ML stat.AP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper, we consider the problem of partitioning a small data sample
drawn from a mixture of $k$ product distributions. We are interested in the
case that individual features are of low average quality $\gamma$, and we want
to use as few of them as possible to correctly partition the sample. We analyze
a spectral technique that is able to approximately optimize the total data
size--the product of number of data points $n$ and the number of features
$K$--needed to correctly perform this partitioning as a function of $1/\gamma$
for $K>n$. Our goal is motivated by an application in clustering individuals
according to their population of origin using markers, when the divergence
between any two of the populations is small.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 08:03:25 GMT"
},
{
"version": "v2",
"created": "Thu, 29 Jan 2009 11:31:54 GMT"
}
] | 2017-11-17T00:00:00 | [
[
"Blum",
"Avrim",
""
],
[
"Coja-Oghlan",
"Amin",
""
],
[
"Frieze",
"Alan",
""
],
[
"Zhou",
"Shuheng",
""
]
] |
0706.3435 | Zoltan Szabo | Zoltan Szabo, Barnabas Poczos, Andras Lorincz | Undercomplete Blind Subspace Deconvolution via Linear Prediction | 12 pages | European Conference on Machine Learning (ECML), pages 740-747,
2007 | null | null | stat.ME | null | We present a novel solution technique for the blind subspace deconvolution
(BSSD) problem, where temporal convolution of multidimensional hidden
independent components is observed and the task is to uncover the hidden
components using the observation only. We carry out this task for the
undercomplete case (uBSSD): we reduce the original uBSSD task via linear
prediction to independent subspace analysis (ISA), which we can solve. As it
has been shown recently, applying temporal concatenation can also reduce uBSSD
to ISA, but the associated ISA problem can easily become `high dimensional'
[1]. The new reduction method circumvents this dimensionality problem. We
perform detailed studies on the efficiency of the proposed technique by means
of numerical simulations. We have found several advantages: our method can
achieve high quality estimations for smaller number of samples and it can cope
with deeper temporal convolutions.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 10:15:39 GMT"
}
] | 2012-01-04T00:00:00 | [
[
"Szabo",
"Zoltan",
""
],
[
"Poczos",
"Barnabas",
""
],
[
"Lorincz",
"Andras",
""
]
] |
0706.3436 | Cecilia Tarantino | Cecilia Tarantino | Rare Kaon Decays Beyond the Standard Model | 10 pages, 2 figures, minor improvements, few references added. Final
version for the proceedings of the International Conference "Kaon'07",
Laboratori Nazionali di Frascati, Italy, 21-25 May 2007 | PoSKAON:057,2008 | null | null | hep-ph | null | The rare kaon decays K_L -> pi^0 nu {bar nu}, K^+ -> pi^+ nu {bar nu}, K_L ->
pi^0 e^+ e^- and K_L -> pi^0 mu^+ mu^- are theoretically very clean and, being
strongly CKM suppressed, highly sensitive to New Physics (NP). Recent Flavour
Physics analyses show that they represent unique probes for revealing NP
effects and to provide information on the NP flavour structure. After a brief
discussion of the main properties that make rare K decays so promising and of
the basic ideas of the most interesting NP models, we review the results of
recent phenomenological analyses both within and beyond the framework of
Minimal Flavour Violation (MFV), where the sources of flavour violation are the
same as in the Standard Model. Within MFV we present the expectations found for
rare K decays from a model-independent analysis and in three MFV models: the
Littlest Higgs (LH) model, the (extra-dimension) Appelquist-Cheng-Dobrescu
model and the Minimal Supersymmetric Standard Model (MSSM) with MFV. Beyond
MFV, we discuss the results recently found within the MSSM (without MFV), the
LH model with T-parity (LHT) and the 3-3-1 (Z') model. While in MFV models only
small (<30%) NP effects are allowed in the branching ratios of K_L -> pi^0 nu
{bar nu}, K^+ -> pi^+ nu {bar nu}, K_L -> pi^0 e^+ e^- and K_L -> pi^0 mu^+
mu^-, beyond MFV, in particular in the MSSM and in the LHT model, large (up to
an order of magnitude) enhancements w.r.t. the SM turn out to be possible.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 15:25:13 GMT"
},
{
"version": "v2",
"created": "Fri, 29 Jun 2007 09:32:45 GMT"
},
{
"version": "v3",
"created": "Mon, 10 Sep 2007 16:00:16 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Tarantino",
"Cecilia",
""
]
] |
0706.3437 | Andrei V. Lebedev | A. V. Lebedev and G. Blatter | Bell's inequality test with time-delayed two-particle correlations | 8 pages, 4 figures | Phys. Rev. B 77, 035301 (2008) | 10.1103/PhysRevB.77.035301 | null | cond-mat.mes-hall cond-mat.str-el quant-ph | null | Adopting the frame of mesoscopic physics, we describe a Bell type experiment
involving time-delayed two-particle correlation measurements. The
indistinguishability of quantum particles results in a specific interference
between different trajectories. We show how the non-locality in the
time-delayed correlations due to the indistinguishability of the quantum
particles manifests itself in the violation of a Bell inequality, where the
degree of violation is related to the accuracy of the measurement. We
demonstrate how the interrelation between the orbital- and the spin exchange
symmetry can by exploited to infer knowledge on spin-entanglement from a
measurement of orbital entanglement.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 09:18:26 GMT"
},
{
"version": "v2",
"created": "Thu, 10 Jan 2008 16:04:39 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lebedev",
"A. V.",
""
],
[
"Blatter",
"G.",
""
]
] |
0706.3438 | Antoni Szczurek | A. Szczurek, A. Rybarska, G. Slipek | Dijet correlations in $pp$ collisions at RHIC | 11 pages, 23 figures, a talk presented at International Workshop on
High-pT physics at LHC, Jyvaskyla, Finland, March 23-27 2007 | null | null | null | hep-ph | null | We compare results of $k_t$-factorization approach and next-to-leading order
collinear-factorization approach for dijet correlations in proton-proton
collisions at RHIC energies. We discuss correlations in azimuthal angle as well
as correlations in two-dimensional space of transverse momenta of two jets.
Some $k_t$-factorization subprocesses are included for the first time in the
literature. Different unintegrated gluon/parton distributions are used in the
$k_t$-factorization approach. The results depend on UGDF/UPDF used. Limitations
due to leading jet condition are discussed.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 09:44:36 GMT"
}
] | 2009-04-16T00:00:00 | [
[
"Szczurek",
"A.",
""
],
[
"Rybarska",
"A.",
""
],
[
"Slipek",
"G.",
""
]
] |
0706.3439 | Antoni Szczurek | M. Luszczak, A. Szczurek | Heavy quark correlations in hadronic collisions | 8 pages, 20 figures, a talk presented at International Workshop on
High-pT physics at LHC, Jyvaskyla, Finland, March 23-27 2007 | PoS LHC07:024,2007 | null | null | hep-ph | null | We discuss results of the $k_t$ - factorization approach for heavy
quark-heavy antiquark correlations in proton-proton and proton-antiproton
collisions for RHIC, Tevatron and LHC. We consider correlations in the
azimuthal angle as well as in the two-dimensional space of transverse momentum
of heavy quark and heavy antiquark. We compare results obtained with the help
of different unintegrated parton distributions (UPDF) from the literature.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 09:40:22 GMT"
}
] | 2011-07-19T00:00:00 | [
[
"Luszczak",
"M.",
""
],
[
"Szczurek",
"A.",
""
]
] |
0706.3440 | Liffman Kurt | Kurt Liffman | The Stellar-Disk Electric (Short) Circuit: Observational Predictions for
a YSO Jet Flow | 6 pages, 8 figures, Accepted for publication in Astrophysics & Space
Science | Astrophys.SpaceSci.311:69-74,2007 | 10.1007/s10509-007-9562-0 | null | astro-ph | null | We discuss the star-disk electric circuit for a young stellar object (YSO)
and calculate the expected torques on the star and the disk. We obtain the same
disk magnetic field and star-disk torques as given by standard
magnetohydrodynamic (MHD) analysis. We show how a short circuit in the
star-disk electric circuit may produce a magnetically-driven jet flow from the
inner edge of a disk surrounding a young star.
An unsteady bipolar jet flow is produced that flows perpendicular to the disk
plane. Jet speeds of order hundreds of kilometres per second are possible,
while the outflow mass loss rate is proportional to the mass accretion rate and
is a function of the disk inner radius relative to the disk co-rotation radius.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 09:30:28 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Liffman",
"Kurt",
""
]
] |
0706.3441 | Michael Temkin | Brian Conrad, Michael Temkin | Non-archimedean analytification of algebraic spaces | 34 pages | null | null | null | math.AG | null | It is now a classical result that an algebraic space locally of finite type
over $\mathbf{C}$ is analytifiable if and only if it is locally separated. In
this paper we study non-archimedean analytifications of algebraic spaces. We
construct a quotient for any etale non-archimedean analytic equivalence
relation whose diagonal is a closed immersion, and deduce that any separated
algebraic space locally of finite type over any non-archimedean field $k$ is
analytifiable in both the category of rigid spaces and the category of analytic
spaces over $k$. Also, though local separatedness remains a necessary condition
for analytifiability in either of these categories, we present many surprising
examples of non-analytifiable locally separated smooth algebraic spaces over
$k$ that can even be defined over the prime field.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 16:08:35 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Conrad",
"Brian",
""
],
[
"Temkin",
"Michael",
""
]
] |
0706.3442 | Antoni Szczurek | T. Pietrycki, A. Szczurek | Photon-jet correlations in hadronic collisions | 7 pages, 12 figures, a talk presented at International Workshop on
High-pT physics at LHC, Jyvaskyla, Finland, March 23-27 2007 | PoSLHC07:029,2007 | null | null | hep-ph | null | We compare results of $k_t$-factorization approach and next-to-leading order
collinear-factorization approach for photon-jet correlations in $pp$ and $p
\bar p$ collisions at RHIC, Tevatron and LHC energies. We discuss correlations
in azimuthal angle as well as in two-dimensional space of transverse momenta of
photon and jet. Different unintegrated parton distributions (UPDF) are included
in the $k_t$-factorization approach. The results depend on UPDFs used. The
results of NLO collinear-factorization are shown for comparison.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 09:35:27 GMT"
}
] | 2009-04-16T00:00:00 | [
[
"Pietrycki",
"T.",
""
],
[
"Szczurek",
"A.",
""
]
] |
0706.3443 | John Aston | Jyh-Ying Peng, John A. D. Aston | The SSM Toolbox for Matlab | Software available from authors | null | null | C-2007-02 | stat.CO stat.AP | null | State Space Models (SSM) is a MATLAB 7.0 software toolbox for doing time
series analysis by state space methods. The software features fully interactive
construction and combination of models, with support for univariate and
multivariate models, complex time-varying (dynamic) models, non-Gaussian
models, and various standard models such as ARIMA and structural time-series
models. The software includes standard functions for Kalman filtering and
smoothing, simulation smoothing, likelihood evaluation, parameter estimation,
signal extraction and forecasting, with incorporation of exact initialization
for filters and smoothers, and support for missing observations and multiple
time series input with common analysis structure. The software also includes
implementations of TRAMO model selection and Hillmer-Tiao decomposition for
ARIMA models. The software will provide a general toolbox for doing time series
analysis on the MATLAB platform, allowing users to take advantage of its
readily available graph plotting and general matrix computation capabilities.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 09:45:48 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Peng",
"Jyh-Ying",
""
],
[
"Aston",
"John A. D.",
""
]
] |
0706.3444 | Ulrich Haisch | Ulrich Haisch | How To Kill a Penguin | 5 pages, 4 figures, 1 table, uses pdflatex, talk given at DIS 2007,
Muenchen, Germany, April 15--20, 2007 | null | null | ZU-TH 10/07 | hep-ph | null | Within constrained minimal-flavor-violation the large destructive
flavor-changing Z-penguin managed to survive eradication so far. We give a
incisive description of how to kill it using the precision measurements of the
Z -> b anti-b pseudo observables. The derived stringent range for the
non-standard contribution to the universal Inami-Lim function C leads to tight
two-sided limits for the branching ratios of all Z-penguin dominated
flavor-changing K- and B-decays.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 10:07:15 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Haisch",
"Ulrich",
""
]
] |
0706.3445 | Emilio Santos Corchero | Emilio Santos | Analysis of a recent experimental test of Bell inequalities violating
quantum predictions | 10 pages, no figures | Eur. Phyis. J. D 46. 531 (2008) | 10.1140/epjd/e2007-00322-3 | null | quant-ph | null | A recent experiment by Brida et al. (arXiv:0705.0439 [quant-ph]) is analyzed
with the conclusion that is shows a violation of standard quantum predictions.
A simple local hidden variables model is studied which is compatible with the
empirical results and fits fairly well the deviation from the quantum
predictions.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 10:09:28 GMT"
}
] | 2021-06-23T00:00:00 | [
[
"Santos",
"Emilio",
""
]
] |
0706.3446 | Rostyslav Vlokh O | R. Vlokh, M. Kostyrko | Estimation of the Birefringence Change in Crystals Induced by
Gravitation Field | 3 pages | Ukr.J.Phys.Opt. 2005 6: 125-127 | 10.3116/16091833/6/4/125/2005 | null | physics.optics physics.space-ph | null | The effect of gravitation field of spherically symmetric mass on the
birefringent properties of crystals has been analysed. It has been shown that
the gravitation field with spherical symmetry can lead to a change of
birefringence in anisotropic media.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 10:14:30 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Vlokh",
"R.",
""
],
[
"Kostyrko",
"M.",
""
]
] |
0706.3447 | Amit Hogadi | Amit Hogadi | Products of Brauer Severi surfaces | 7 pages | null | null | null | math.AG | null | Let $\{P_i\}_{1 \leq i \leq r}$ and $\{Q_i\}_{1 \leq i \leq r}$ be two
collections of Brauer Severi surfaces (resp. conics) over a field $k$. We show
that the subgroup generated by the $P_i's$ in $Br(k)$ is the same as the
subgroup generated by the $Q_i's$ \iff $\Pi P_i $ is birational to $\Pi Q_i$.
Moreover in this case $\Pi P_i$ and $\Pi Q_i$ represent the same class in
$M(k)$, the Grothendieck ring of $k$-varieties. The converse holds if
$char(k)=0$. Some of the above implications also hold over a general noetherian
base scheme.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 10:19:43 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Hogadi",
"Amit",
""
]
] |
0706.3448 | Zhen Yan | N. Wang, Z. Yan, R. N. Manchester, and H. X. Wang | Daily Observations of Interstellar Scintillation in PSR B0329+54 | 10 pages, 5 figures, Accepted by MNRAS | null | 10.1111/j.1365-2966.2008.12864.x | null | astro-ph | null | Quasi-continuous observations of PSR B03239+54 over 20 days using the Nanshan
25-m telescope at 1540 MHz have been used to study the effects of refractive
scintillation on the pulsar flux density and diffractive scintillation
properties. Dynamic spectra were obtained from datasets of 90 min duration and
diffractive parameters derived from a two-dimensional auto-correlation
analysis. Secondary spectra were also computed but these showed no significant
evidence for arc structure. Cross correlations between variations in the
derived parameters were much lower than predicted by thin screen models and in
one case was of opposite sign to the prediction. Observed modulation indices
were larger than predicted by thin screen models with a Kolmogorov fluctuation
spectrum. Structure functions were computed for the flux density, diffractive
timescale and decorrelation bandwidth. These indicated a refractive timescale
of $8\pm 2$ h, much shorter than predicted by the thin screen model. The
measured structure-function slope of $0.4\pm 0.2$ is also inconsistent with
scattering by a single thin screen for which a slope of 2.0 is expected. All
observations are consistent with scattering by an extended medium having a
Kolmogorov fluctuation spectrum which is concentrated towards the pulsar. This
interpretation is also consistent with recent observations of multiple diffuse
scintillation arcs for this pulsar.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 11:20:40 GMT"
},
{
"version": "v2",
"created": "Tue, 18 Dec 2007 13:05:09 GMT"
},
{
"version": "v3",
"created": "Tue, 19 Feb 2008 14:10:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wang",
"N.",
""
],
[
"Yan",
"Z.",
""
],
[
"Manchester",
"R. N.",
""
],
[
"Wang",
"H. X.",
""
]
] |
0706.3449 | Cojocaru | S. Cojocaru, R. Citro and M. Marinaro | Incoherent mid-infrared charge excitation and the high energy anomaly in
the photoemission spectra of cuprates | 12 pages, 3 figures | null | 10.1103/PhysRevB.75.220502 | null | cond-mat.mtrl-sci | null | On the basis of a semi-phenomenological model, it is argued that the high
energy anomaly observed in recent photoemission experiments on cuprates is
caused by interaction with an overdamped bosonic mode in the mid-infrared
region of the spectrum. Analysis of optical conductivity allows to connect this
excitation to the incoherent charge response reported for the majority of high
Tc materials and some other perovskites. We show that its large damping is an
essential feature responsible for the "waterfall" dispersion and linewidth of
the spectral weight.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 10:54:51 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cojocaru",
"S.",
""
],
[
"Citro",
"R.",
""
],
[
"Marinaro",
"M.",
""
]
] |
0706.3450 | Behrouz Mirza | Behrouz Mirza, Mohammad Zamani-Nasab | Ruppeiner Geometry of RN Black Holes: Flat or Curved? | 9 pages | JHEP 0706:059,2007 | 10.1088/1126-6708/2007/06/059 | null | hep-th | null | In some recent studies \cite{aman1, aman2, aman3}, Aman {\it et al.} used the
Ruppeiner scalar as a measure of underlying interactions of
Reissner-Nordstr\"{o}m black holes, indicating that it is a non-interacting
statistical system for which classical thermodynamics could be used at any
scale. Here, we show that if we use the complete set of thermodynamic
variables, a non-flat state space will be produced. Furthermore, the Ruppeiner
curvature diverges at extremal limits, as it would for other types of black
holes.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 10:59:17 GMT"
}
] | 2010-10-27T00:00:00 | [
[
"Mirza",
"Behrouz",
""
],
[
"Zamani-Nasab",
"Mohammad",
""
]
] |
0706.3451 | Petter Andreas Bergh | Petter Andreas Bergh | Complexity test modules | 11 pages | null | null | null | math.AC | null | A method is provided for computing an upper bound of the complexity of a
module over a local ring, in terms of vanishing of certain cohomology modules.
We then specialize to complete intersections, which are precisely the rings
over which all modules have finite complexity.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 11:47:58 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Bergh",
"Petter Andreas",
""
]
] |
0706.3452 | Luis Nunez A | H. Abreu, H. Hernandez and L.A. Nunez | Sound Speeds, Cracking and Stability of Self-Gravitating Anisotropic
Compact Objects | 17 pages, 8 figures, 4 new references added. typos corrected | Class.Quant.Grav.24:4631-4646,2007 | 10.1088/0264-9381/24/18/005 | null | gr-qc | null | Using the the concept of cracking we explore the influence of density
fluctuations and local anisotropy have on the stability of local and non-local
anisotropic matter configurations in general relativity. This concept,
conceived to describe the behaviour of a fluid distribution just after its
departure from equilibrium, provides an alternative approach to consider the
stability of selfgravitating compact objects. We show that potentially unstable
regions within a configuration can be identify as a function of the difference
of propagations of sound along tangential and radial directions. In fact, it is
found that these regions could occur when, at particular point within the
distribution, the tangential speed of sound is greater than radial one.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 12:15:22 GMT"
},
{
"version": "v2",
"created": "Sun, 22 Jul 2007 16:57:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Abreu",
"H.",
""
],
[
"Hernandez",
"H.",
""
],
[
"Nunez",
"L. A.",
""
]
] |
0706.3453 | Victor Abramovsky | N.V. Radchenko | About agreement of PYTHIA and the experimental results in $e^+e^-$
annihilation to hadrons | 17 pages, 9 figures | null | null | null | hep-ph | null | The experimental charged particles multiplicity distributions in $e^+e^-$
annihilation to hadrons are compared with the distributions obtained by PYTHIA.
The ratio $\chi^2$/degrees of freedom is calculated for 6 energies at
$\sqrt{s}$ 14 -- 206.2 GeV. The necessity of more subtle tuning of PYTHIA at
the energy of $Z^0$ peak is discussed.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 12:40:52 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Radchenko",
"N. V.",
""
]
] |
0706.3454 | Igor Tralle | A.A.Suzko, I.Tralle | Reconstruction of Quantum Well Potentials via the Intertwining Operator
Technique | null | null | null | null | cond-mat.mes-hall | null | One of the most important issues of quantum engineering is the construction
of low-dimensional structures possessing desirable properties. For example, in
different areas of possible applications of the structures containing quantum
wells (QW), there is need to have QW energy spectrum, which is predetermined.
Then the following question arises: can one reconstruct the shape of QW which
supports this spectrum? We outline the possible strategy of the QW potential
shape reconstruction, if the spectrum of QW is given in advance. The proposed
approach is based on the combination of different techniques such as Inverse
Scattering Problem Method, Darboux and Liouville transformation. It enables to
take into account the space-variable dependent effective mass of charge
carriers and allows the kinetic energy operator to be of non-Hermitian as well
as Hermitian form. The proposed technique allows to construct phase-equivalent
potentials, to add the new bounded states to (or remove some of them from) the
spectrum supported by an initial potential and provides a systematic procedure
for generating new exactly solvable models.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 12:49:22 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Suzko",
"A. A.",
""
],
[
"Tralle",
"I.",
""
]
] |
0706.3455 | Vasily E. Tarasov | Vasily E. Tarasov | Thermodynamics of Few-Particle Systems | 19 pages, LaTeX | International Journal of Modern Physics B 19 (2005) 879-897 | 10.1142/S0217979205027780 | null | math-ph math.MP | null | We consider the wide class of few-particle systems that have some analog of
the thermodynamic laws. These systems are characterized by the distributions
that are determined by the Hamiltonian and satisfy the Liouville equation.
Few-particle systems of this class are described by a non-holonomic constraint:
the power of non-potential forces is directly proportional to the velocity of
the elementary phase volume change. The coefficient of this proportionality is
determined by the Hamiltonian. In the general case, the examples of the
few-particle systems of this class are the constant temperature systems,
canonical-dissipative systems, and Fermi-Bose classical systems.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 12:57:32 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tarasov",
"Vasily E.",
""
]
] |
0706.3456 | Stefan Kettemann | A. Zhuravlev, I. Zharekeshev, E. Gorelov, A. I. Lichtenstein, E. R.
Mucciolo, S. Kettemann | Nonperturbative Scaling Theory of Free Magnetic Moment Phases in
Disordered Metals | 4 pages, 6 figures | Phys. Rev. Lett. 99, 247202 (2007) | 10.1103/PhysRevLett.99.247202 | null | cond-mat.str-el cond-mat.mes-hall | null | The crossover between a free magnetic moment phase and a Kondo phase in low
dimensional disordered metals with dilute magnetic impurities is studied.
We perform a finite size scaling analysis of the distribution of the Kondo
temperature as obtained from a numerical renormalization group calculation of
the local magnetic susceptibility and from the solution of the self-consistent
Nagaoka-Suhl equation. We find a sizable fraction of free (unscreened) magnetic
moments when the exchange coupling falls below a disorder-dependent critical
value $J_{\rm c}$. Our numerical results show that between the free moment
phase due to Anderson localization and the Kondo screened phase there is a
phase where free moments occur due to the appearance of random local pseudogaps
at the Fermi energy whose width and power scale with the elastic scattering
rate $1/\tau$.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 13:01:48 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zhuravlev",
"A.",
""
],
[
"Zharekeshev",
"I.",
""
],
[
"Gorelov",
"E.",
""
],
[
"Lichtenstein",
"A. I.",
""
],
[
"Mucciolo",
"E. R.",
""
],
[
"Kettemann",
"S.",
""
]
] |
0706.3457 | Lan Zhou | Lan Zhou, Jing Lu, D. L. Zhou, C. P. Sun | Quantum theory for spatial motion of polaritons in inhomogeneous fields | 13 pages, 5 figures | Phys. Rev. A 77, 023816 (2008) | 10.1103/PhysRevA.77.023816 | null | quant-ph | null | Polaritons are the collective excitations of many atoms dressed by resonant
photons, which can be used to explain the slow light propagation with the
mechanism of electromagnetically induced transparency. As quasi-particles,
these collective excitations possess the typical feature of the matter
particles, which can be reflected and deflected by the inhomogeneous medium in
its spatial motion with some velocity. In this paper we develop a quantum
theory to systematically describe the spatial motion of polaritons in
inhomogeneous magnetic and optical fields. This theoretical approach treats
these quasi-particles through an effective Schr\"{o}dinger equation with
anisotropic depression that the longitudinal motion is like a
ultra-relativistic motion of a "slow light velocity" while the transverse
motion is of non-relativity with certain effective mass. We find that, after
passing through the EIT medium, the light ray bends due to the
spatial-dependent profile of external field. This phenomenon explicitly
demonstrates the exotic corpuscular property of polaritons with anisotropic
nature.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 13:59:01 GMT"
},
{
"version": "v2",
"created": "Wed, 4 Jul 2007 06:19:08 GMT"
},
{
"version": "v3",
"created": "Mon, 18 Feb 2008 02:28:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zhou",
"Lan",
""
],
[
"Lu",
"Jing",
""
],
[
"Zhou",
"D. L.",
""
],
[
"Sun",
"C. P.",
""
]
] |
0706.3458 | Fred Hucht | Alfred Hucht | The Thermodynamic Casimir Effect in $^4$He Films near $T_\lambda$: Monte
Carlo Results | 5 pages, 4 figures, accepted for publication in Phys. Rev. Lett | Phys. Rev. Lett. 99, 185301 (2007) | 10.1103/PhysRevLett.99.185301 | null | cond-mat.stat-mech | null | The universal finite-size scaling function of the critical Casimir force for
the three dimensional XY universality class with Dirichlet boundary conditions
is determined using Monte Carlo simulations. The results are in excellent
agreement with recent experiments on $^4$He Films at the superfluid transition
and with available theoretical predictions.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 15:29:54 GMT"
},
{
"version": "v2",
"created": "Thu, 5 Jul 2007 23:27:55 GMT"
},
{
"version": "v3",
"created": "Tue, 18 Sep 2007 09:56:57 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Hucht",
"Alfred",
""
]
] |
0706.3459 | Gabor Kun | Gabor Kun, Jaroslav Nesetril | NP by means of lifts and shadows | 12 pages, conference (MFCS07) version of 0706.1704 | null | null | null | cs.CC math.CO | null | We show that every NP problem is polynomially equivalent to a simple
combinatorial problem: the membership problem for a special class of digraphs.
These classes are defined by means of shadows (projections) and by finitely
many forbidden colored (lifted) subgraphs. Our characterization is motivated by
the analysis of syntactical subclasses with the full computational power of NP,
which were first studied by Feder and Vardi.
Our approach applies to many combinatorial problems and it induces the
characterization of coloring problems (CSP) defined by means of shadows. This
turns out to be related to homomorphism dualities. We prove that a class of
digraphs (relational structures) defined by finitely many forbidden colored
subgraphs (i.e. lifted substructures) is a CSP class if and only if all the the
forbidden structures are homomorphically equivalent to trees. We show a
surprising richness of coloring problems when restricted to most frequent graph
classes. Using results of Ne\v{s}et\v{r}il and Ossona de Mendez for bounded
expansion classes (which include bounded degree and proper minor closed
classes) we prove that the restriction of every class defined as the shadow of
finitely many colored subgraphs equals to the restriction of a coloring (CSP)
class.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 15:40:43 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Kun",
"Gabor",
""
],
[
"Nesetril",
"Jaroslav",
""
]
] |
0706.3460 | Raffaella Landi Dr | R. Landi, N. Masetti, L. Morelli, E. Palazzi, L. Bassani, A. Malizia,
A. Bazzano, A.J. Bird, A.J. Dean, G. Galaz, D. Minniti, P. Ubertini | The AGN nature of 11 out of 12 Swift/RXTE unidentified sources through
optical and X-ray spectroscopy | 50 pages, including 16 figures and 7 tables. Accepted for publication
in ApJ | null | 10.1086/521208 | null | astro-ph | null | The Swift Burst Alert Telescope (BAT) is performing a high Galactic latitude
survey in the 14-195 keV band at a flux limit of ~10^{-11} erg cm^{-2} s^{-1},
leading to the discovery of new high energy sources, most of which have not so
far been properly classified. A similar work has also been performed with the
RXTE slew survey leading to the discovery of 68 sources detected above 8 keV,
many of which are still unclassified. Follow-up observations with the Swift
X-ray Telescope (XRT) provide, for many of these objects, source localization
with a positional accuracy of few arcsec, thus allowing the search for optical
counterparts to be more efficient and reliable. We present the results of
optical/X-ray follow-up studies of 11 Swift BAT detections and one AGN detected
in the RXTE Slew Survey, aimed at identifying their counterparts and at
assessing their nature. These data allowed, for the first time, the optical
classification of 8 objects and a distance determination for 3 of them. For
another object, a more refined optical classification than that available in
the literature is also provided. For the remaining sources, optical
spectroscopy provides a characterization of the source near in time to the
X-ray measurement. The sample consists of 6 Seyfert 2 galaxies, 5 Seyferts of
intermediate type 1.2-1.8, and one object of Galactic nature - an Intermediate
Polar (i.e., magnetic) Cataclysmic Variable. Out of the 11 AGNs, 8 (~70%)
including 2 Seyferts of type 1.2 and 1.5, are absorbed with NH > 10^{22}
cm^{-2}. Up to 3 objects could be Compton thick (i.e. NH > 1.5 x 10^{24}
cm^{-2}), but only in one case (Swift J0609.1-8636) does all the observational
evidence strongly suggests this possibility.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 16:27:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Landi",
"R.",
""
],
[
"Masetti",
"N.",
""
],
[
"Morelli",
"L.",
""
],
[
"Palazzi",
"E.",
""
],
[
"Bassani",
"L.",
""
],
[
"Malizia",
"A.",
""
],
[
"Bazzano",
"A.",
""
],
[
"Bird",
"A. J.",
""
],
[
"Dean",
"A. J.",
""
],
[
"Galaz",
"G.",
""
],
[
"Minniti",
"D.",
""
],
[
"Ubertini",
"P.",
""
]
] |
0706.3461 | Ol'khov | O.A. Olkhov | Geometrization of quantum formalism | 11 pages, Proc.Int.WorkshopDICE2006 "Quantum Mechanics between
Decoherence and Determinism", Piombino, Italy, September 11-15, 2006 | Journal of Phys.: Conf.Ser, 2007, 67, 012037 | null | null | quant-ph | null | The hypothesis is suggested that the equation for the Dirac free wave field
is, in fact, a group-theoretical relation describing propagation of specific
microscopic deviations of space geometry from the euclidean one (closed
topological manifolds). The Dirac equation for a hydrogen atom can also be
interpreted as a relation that accounts for the symmetry properties of a piece
of curved space. Within the framework of this concept, atoms have no any
pointlike particles (electrons) inside, and the gauge invariance of
electromagnetic field proves to be the natural consequence of the basic
principles of the proposed geometrical approach.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 16:34:13 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Olkhov",
"O. A.",
""
]
] |
0706.3462 | Eckart Viehweg | Martin Moeller, Eckart Viehweg, Kang Zuo | Stability of Hodge bundles and a numerical characterization of Shimura
varieties | 65 pages, AMSLaTeX. Some more corrections and supplements. We
reformulated large parts of Sections 2, 4, 5, 6, and 7. In particular we
filled a gap in the proof of 6.4., corrected several mistakes in Section 7
and added some references | null | null | null | math.AG math.CV | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Consider a family f:A --> U of g-dimensional abelian varieties over a
quasiprojective manifold U. Suppose that the induced map from U to the moduli
scheme of polarized abelian varieties is generically finite and that there is a
projective manifold Y, containing U as the complement of a normal crossing
divisor S, such that the sheaf of logarithmic one forms is nef and that its
determinant is ample with respect to U. We characterize whether $U$ is a
Shimura variety by numerical data attached to the variation of Hodge
structures, rather than by properties of the map from U to the moduli scheme or
by the existence of CM points. More precisely, we show that U is a Shimura
variety, if and only if two conditions hold. First, each irreducible local
subsystem V of the complex weight one variation of Hodge structures is either
unitary or satisfies the Arakelov equality. Secondly, for each factor M in the
universal cover of U whose tangent bundle behaves like the one of a complex
ball, an iterated Kodaira-Spencer map associated with V has minimal possible
length in the direction of M.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 16:42:19 GMT"
},
{
"version": "v2",
"created": "Fri, 2 Nov 2007 14:50:48 GMT"
},
{
"version": "v3",
"created": "Thu, 12 Feb 2009 11:04:09 GMT"
},
{
"version": "v4",
"created": "Mon, 12 Oct 2009 09:41:07 GMT"
}
] | 2009-10-12T00:00:00 | [
[
"Moeller",
"Martin",
""
],
[
"Viehweg",
"Eckart",
""
],
[
"Zuo",
"Kang",
""
]
] |
0706.3463 | Magdalena Musat | Uffe Haagerup, Magdalena Musat | Classification of hyperfinite factors up to completely bounded
isomorphism of their preduals | 30 pages | null | null | null | math.OA | null | In this paper we consider the following problem: When are the preduals of two
hyperfinite (=injective) factors $\M$ and $\N$ (on separable Hilbert spaces)
cb-isomorphic (i.e., isomorphic as operator spaces)? We show that if $\M$ is
semifinite and $\N$ is type III, then their preduals are not cb-isomorphic.
Moreover, we construct a one-parameter family of hyperfinite type
III$_0$-factors with mutually non cb-isomorphic preduals, and we give a
characterization of those hyperfinite factors $\M$ whose preduals are
cb-isomorphic to the predual of the unique hyperfinite type III$_1$-factor. In
contrast, Christensen and Sinclair proved in 1989 that all infinite dimensional
hyperfinite factors with separable preduals are cb-isomorphic. More recently
Rosenthal, Sukochev and the first-named author proved that all hyperfinite type
III$_\lambda$-factors, where $0< \lambda\leq 1$, have cb-isomorphic preduals.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 17:07:46 GMT"
},
{
"version": "v2",
"created": "Wed, 8 Aug 2007 21:03:19 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Haagerup",
"Uffe",
""
],
[
"Musat",
"Magdalena",
""
]
] |
0706.3464 | Tim Davidge | T. J. Davidge | The Disk and Extraplanar Regions of NGC 2403 | 49 pages, including 17 figures. To appear in ApJ | Astrophys.J.664:820-839,2007 | 10.1086/519232 | null | astro-ph | null | Wide field images obtained with WIRCam and MegaCam on the
Canada-France-Hawaii Telescope are used to probe the spatial distribution of
young stars in the Sc galaxy NGC 2403. Bright main sequence stars and blue
supergiants are detected out to projected galactocentric distances of ~14 kpc
(~7 disk scale lengths) along the major axis. The star formation rate (SFR) in
the disk of NGC 2403 during the past 10 Myr has been 1 solar masses per year
based on the number of bright main sequence stars. The radially-averaged number
density of red supergiants (RSGs) per unit r-band surface brightness is
constant throughout the disk, indicating that (1) RSGs follow the integrated
r-band light, and (2) the SFR per unit mass has been constant with radius when
averaged over time scales of a few tens of millions of years. The mean color of
RSGs varies with galactocentric distance, suggesting that there is a
metallicity gradient among recently formed stars. A comparison of the
radially-averaged number density of bright main sequence stars also indicates
that the SFR per unit stellar mass in NGC 2403 has been ~3 times higher than in
NGC 247 during recent epochs, and this is in rough agreement with what would be
predicted from the far infrared fluxes of these galaxies. Finally, the data are
used to investigate the extraplanar regions of NGC 2403. A population of M
giants with peak brightness M_K = -8 is detected at projected distances between
12 and 14 kpc above the disk plane, and six new globular cluster candidates are
identified.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 19:21:33 GMT"
}
] | 2011-02-11T00:00:00 | [
[
"Davidge",
"T. J.",
""
]
] |
0706.3465 | Kazuhide Ichikawa | Kazuhide Ichikawa | Cosmological Constraint on the Effective Number of Neutrino Species | 8 pages, 3 figures. Proceedings for the XIXth Rencontres de Blois,
May 2007 | null | null | null | astro-ph | null | We discuss constraints on the effective number of neutrino species Nnu from
recent cosmological observations such as CMB, LSS, BBN, including our own
analysis which uses the WMAP and the Luminous Red Galaxy power spectrum data.
We also discuss their implications on some non-standard cosmological scenarios
such as the low (MeV-scale) reheating temperature scenario and the scenario
with decaying particles between BBN and structure formation.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 17:24:31 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Ichikawa",
"Kazuhide",
""
]
] |
0706.3466 | Stefano Bellucci | S. Bellucci, S. Krivonos and A. Sutulin | N=8 supersymmetric mechanics on the sphere S^3 | 9 pages, LaTeX file, PACS: 11.30.Pb, 03.65.-w | Phys.Rev.D76:065017,2007 | 10.1103/PhysRevD.76.065017 | null | hep-th | null | Starting from quaternionic N=8 supersymmetric mechanics we perform a
reduction over a bosonic radial variable, ending up with a nonlinear off-shell
supermultiplet with three bosonic end eight fermionic physical degrees of
freedom. The geometry of the bosonic sector of the most general sigma-model
type action is described by an arbitrary function obeying the three dimensional
Laplace equation on the sphere S^3. Among the bosonic components of this new
supermultiplet there is a constant which gives rise to potential terms. After
dualization of this constant one may come back to the supermultiplet with four
physical bosons. However, this new supermultiplet is highly nonlinear. The
geometry of the corresponding sigma-model action is briefly discussed.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 17:25:43 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Jul 2007 13:14:03 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bellucci",
"S.",
""
],
[
"Krivonos",
"S.",
""
],
[
"Sutulin",
"A.",
""
]
] |
0706.3467 | Burin Gumjudpai | Burin Gumjudpai (TPTP Naresuan U.) | Coupled phantom field in loop quantum cosmology | 5 pages, 5 figures, invited talk at the SIAM Physics Congress 2007
and the Thai National Astronomy Meeting 2007, Nakorn Pathom, Thailand | Thai Journal of Physics Series 3: Proceedings of the SIAM Physics
Congress 2007 and the Thai National Astronomy Meeting 2007 | null | null | gr-qc astro-ph hep-th | null | A model of phantom scalar field dark energy under exponential potential
coupling to barotropic dark matter fluid in loop quantum cosmology is addressed
here. We derive a closed-autonomous system for cosmological dynamics in this
scenario. The expansion in loop quantum universe has a bounce even in presence
of the phantom field. The greater decaying from dark matter to dark phantom
energy results in greater energy storing in the phantom field. This results in
further turning point of the field. Greater coupling also delays bouncing time.
In the case of phantom decaying, oscillation in phantom density makes small
oscillation in the increasing matter density.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 17:49:27 GMT"
},
{
"version": "v2",
"created": "Tue, 3 Jul 2007 16:50:14 GMT"
}
] | 2008-04-18T00:00:00 | [
[
"Gumjudpai",
"Burin",
"",
"TPTP Naresuan U."
]
] |
0706.3468 | Magno Machado | M.B. Gay Ducati, M.M. Machado, M.V.T. Machado | Investigating diffractive W production in hadron-hadron collisions at
high energies | 4 pages, 1 table. To appear in the proceedings of 10th International
Workshop on Hadron Physics (X Hadron Physics), Florianopolis, Brazil, 26-31
Mar 2007 | Int.J.Mod.Phys.E16:2956-2960,2007 | 10.1142/S0218301307008811 | null | hep-ph | null | We compute the hard diffractive hadroproduction of bosons W at high energies
using Regge factorization and taking into account multiple Pomeron exchange
corrections. The ratio of diffractive to non-diffractive W production agrees
with the current Tevatron data and a prediction for the LHC is presented.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 18:14:06 GMT"
}
] | 2010-11-26T00:00:00 | [
[
"Ducati",
"M. B. Gay",
""
],
[
"Machado",
"M. M.",
""
],
[
"Machado",
"M. V. T.",
""
]
] |
0706.3469 | Michael Spanner | Michael Spanner and Paul Brumer | Entanglement and Timing-Based Mechanisms in the Coherent Control of
Scattering Processes | null | null | 10.1103/PhysRevA.76.013408 | null | quant-ph physics.atom-ph physics.chem-ph | null | The coherent control of scattering processes is considered, with electron
impact dissociation of H$_2^+$ used as an example. The physical mechanism
underlying coherently controlled stationary state scattering is exposed by
analyzing a control scenario that relies on previously established entanglement
requirements between the scattering partners. Specifically, initial state
entanglement assures that all collisions in the scattering volume yield the
desirable scattering configuration. Scattering is controlled by preparing the
particular internal state wave function that leads to the favored collisional
configuration in the collision volume. This insight allows coherent control to
be extended to the case of time-dependent scattering. Specifically, we identify
reactive scattering scenarios using incident wave packets of translational
motion where coherent control is operational and initial state entanglement is
unnecessary. Both the stationary and time-dependent scenarios incorporate
extended coherence features, making them physically distinct. From a
theoretical point of view, this work represents a large step forward in the
qualitative understanding of coherently controlled reactive scattering. From an
experimental viewpoint, it offers an alternative to entanglement-based control
schemes. However, both methods present significant challenges to existing
experimental technologies.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 18:10:47 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Spanner",
"Michael",
""
],
[
"Brumer",
"Paul",
""
]
] |
0706.3470 | Michael Spanner | Michael Spanner and Paul Brumer | Coherent Control and Entanglement in the Attosecond Electron Recollision
Dissociation of D2+ | null | null | 10.1103/PhysRevA.76.013409 | null | quant-ph physics.atom-ph physics.chem-ph | null | We examine the attosecond electron recollision dissociation of D2+ recently
demonstrated experimentally [H. Niikura et al., Nature (London) 421, 826
(2003)] from a coherent control perspective. In this process, a strong laser
field incident on D2 ionizes an electron, accelerates the electron in the laser
field to eV energies, and then drives the electron to recollide with the parent
ion, causing D2+ dissociation. A number of results are demonstrated. First, a
full dimensional Strong Field Approximation (SFA) model is constructed and
shown to be in agreement with the original experiment. This is then used to
rigorously demonstrate that the experiment is an example of coherent pump-dump
control. Second, extensions to bichromatic coherent control are proposed by
considering dissociative recollision of molecules prepared in a coherent
superposition of vibrational states. Third, by comparing the results to similar
scenarios involving field-free attosecond scattering of independently prepared
D2+ and electron wave packets, recollision dissociation is shown to provide an
example of wave-packet coherent control of reactive scattering. Fourth, this
analysis makes clear that it is the temporal correlations between the continuum
electron and D2+ wave packet, and not entanglement, that are crucial for the
sub-femtosecond probing resolution demonstrated in the experiment. This result
clarifies some misconceptions regarding the importance of entanglement in the
recollision probing of D2+. Finally, signatures of entanglement between the
recollision electron and the atomic fragments, detectable via coincidence
measurements, are identified.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 18:22:31 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Spanner",
"Michael",
""
],
[
"Brumer",
"Paul",
""
]
] |
0706.3471 | Jonathan R. Friedman | M. Bal, Jonathan R. Friedman, W. Chen, M. T. Tuominen, C. C. Beedle,
E. M. Rumberger and D. N. Hendrickson | Radiation- and Phonon-Bottleneck-Induced Tunneling in the Fe8
Single-Molecule Magnet | 6 RevTeX pages, including 4 EPS figures, version accepted for
publication | Europhys. Lett., 82, 17005 (2008) | 10.1209/0295-5075/82/17005 | null | cond-mat.mes-hall cond-mat.mtrl-sci | null | We measure magnetization changes in a single crystal of the single-molecule
magnet Fe8 when exposed to intense, short (<20 $\mu$s) pulses of microwave
radiation resonant with the m = 10 to 9 transition. We find that radiation
induces a phonon bottleneck in the system with a time scale of ~5 $\mu$s. The
phonon bottleneck, in turn, drives the spin dynamics, allowing observation of
thermally assisted resonant tunneling between spin states at the 100-ns time
scale. Detailed numerical simulations quantitatively reproduce the data and
yield a spin-phonon relaxation time of T1 ~ 40 ns.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 19:12:58 GMT"
},
{
"version": "v2",
"created": "Fri, 14 Mar 2008 03:10:19 GMT"
}
] | 2008-03-14T00:00:00 | [
[
"Bal",
"M.",
""
],
[
"Friedman",
"Jonathan R.",
""
],
[
"Chen",
"W.",
""
],
[
"Tuominen",
"M. T.",
""
],
[
"Beedle",
"C. C.",
""
],
[
"Rumberger",
"E. M.",
""
],
[
"Hendrickson",
"D. N.",
""
]
] |
0706.3472 | Erick Herbin | Erick Herbin and Ely Merzbach | Stationarity and Self-similarity Characterization of the Set-indexed
Fractional Brownian Motion | 18 pages | null | null | null | math.PR | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The set-indexed fractional Brownian motion (sifBm) has been defined by
Herbin-Merzbach (2006) for indices that are subsets of a metric measure space.
In this paper, the sifBm is proved to statisfy a strenghtened definition of
increment stationarity. This new definition for stationarity property allows to
get a complete characterization of this process by its fractal properties: The
sifBm is the only set-indexed Gaussian process which is self-similar and has
stationary increments.
Using the fact that the sifBm is the only set-indexed process whose
projection on any increasing path is a one-dimensional fractional Brownian
motion, the limitation of its definition for a self-similarity parameter
0<H<1/2 is studied, as illustrated by some examples. When the indexing
collection is totally ordered, the sifBm can be defined for 0<H<1.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 19:16:55 GMT"
},
{
"version": "v2",
"created": "Tue, 6 May 2008 20:47:47 GMT"
},
{
"version": "v3",
"created": "Wed, 9 Jul 2008 10:05:34 GMT"
}
] | 2008-07-09T00:00:00 | [
[
"Herbin",
"Erick",
""
],
[
"Merzbach",
"Ely",
""
]
] |
0706.3473 | Eugene Loginov | E.K. Loginov | On a class of gauge theories | 18 pages, LaTeX, no figures | J.Math.Phys.48:073522,2007 | 10.1063/1.2749173 | null | hep-th | null | We give a framework to describe gauge theory in which a nonassociative
Moufang loop takes the place of the structure group. The structure of such
gauge theory has many formal similarities with that of Yang-Mills theory. We
extend the gauge invariance to this theory and construct an on-shell version of
N=1 supersymmetric gauge theory.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 19:36:24 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Loginov",
"E. K.",
""
]
] |
0706.3474 | Chia-Fu Yu | Chia-Fu Yu | An exact geometric mass formula | 8 pages | null | null | null | math.NT | null | We show an exact geometric mass formula for superspecial points in the
reduction of any quaternionic Shimura variety modulo at a good prime $p$.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 20:02:19 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Yu",
"Chia-Fu",
""
]
] |
0706.3475 | Da Xu | Da Xu | Emergence of time and Observable physics | This paper has been withdrawn | null | null | null | physics.gen-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This is a philosophy paper rather than mathematical physics work. I will
publish it in some other place.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 20:09:38 GMT"
},
{
"version": "v2",
"created": "Sat, 14 Jul 2007 01:03:25 GMT"
},
{
"version": "v3",
"created": "Thu, 2 Aug 2007 03:58:43 GMT"
},
{
"version": "v4",
"created": "Mon, 17 Aug 2009 16:43:42 GMT"
}
] | 2009-08-17T00:00:00 | [
[
"Xu",
"Da",
""
]
] |
0706.3476 | Anton Gerasimov | A. Gerasimov, D. Lebedev and S. Oblezin | Baxter operator and Archimedean Hecke algebra | 32 pages, typos corrected, | null | 10.1007/s00220-008-0547-9 | null | math.RT | null | In this paper we introduce Baxter integral Q-operators for finite-dimensional
Lie algebras gl(n+1) and so(2n+1). Whittaker functions corresponding to these
algebras are eigenfunctions of the Q-operators with the eigenvalues expressed
in terms of Gamma-functions. The appearance of the Gamma-functions is one of
the manifestations of an interesting connection between Mellin-Barnes and
Givental integral representations of Whittaker functions, which are in a sense
dual to each other. We define a dual Baxter operator and derive a family of
mixed Mellin-Barnes-Givental integral representations. Givental and
Mellin-Barnes integral representations are used to provide a short proof of the
Friedberg-Bump and Bump conjectures for G=GL(n+1) proved earlier by Stade. We
also identify eigenvalues of the Baxter Q-operator acting on Whittaker
functions with local Archimedean L-factors. The Baxter Q-operator introduced in
this paper is then described as a particular realization of the explicitly
defined universal Baxter operator in the spherical Hecke algebra H(G(R),K), K
being a maximal compact subgroup of G. Finally we stress an analogy between
Q-operators and certain elements of the non-Archimedean Hecke algebra
H(G(Q_p),G(Z_p)).
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 20:34:58 GMT"
},
{
"version": "v2",
"created": "Fri, 24 Aug 2007 18:36:39 GMT"
},
{
"version": "v3",
"created": "Thu, 11 Oct 2007 06:32:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Gerasimov",
"A.",
""
],
[
"Lebedev",
"D.",
""
],
[
"Oblezin",
"S.",
""
]
] |
0706.3477 | Robbe Wunschiers | Robbe Wunschiers and Martin Vellguth | OrfMapper: A Web-Based Application for Visualizing Gene Clusters on
Metabolic Pathway Maps | 5 pages, 1 figure | null | null | null | q-bio.GN | null | Computational analyses of, e.g., genomic, proteomic, or metabolomic data,
commonly result in one or more sets of candidate genes, proteins, or enzymes.
These sets are often the outcome of clustering algorithms. Subsequently, it has
to be tested if, e.g., the candidate gene-products are members of known
metabolic processes. With OrfMapper we provide a powerful but easy-to-use,
web-based database application, that supports such analyses. All services
provided by OrfMapper are freely available at http://www.orfmapper.com
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 20:39:57 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Wunschiers",
"Robbe",
""
],
[
"Vellguth",
"Martin",
""
]
] |
0706.3478 | Ben Moonen | Ben Moonen | Relations between tautological cycles on Jacobians | 24 pages, 2 figures. Added a conjecture of van der Geer and
Kouvidakis. Corrected minor mistakes | null | null | null | math.AG | null | We study tautological cycle classes on the Jacobian of a curve. We prove a
new result about the ring of tautological classes on a general curve that
allows, among other things, easy dimension calculations and leads to some
general results about the structure of this ring. Next we obtain a vanishing
result for some of the generating classes p_i; this gives an improvement of an
earlier result of Herbaut. Finally we lift a result of Herbaut and van der
Geer-Kouvidakis to the Chow ring (as opposed to its quotient modulo algebraic
equivalence) and we give a method to obtain further explicit cycle relations.
As an ingredient for this we prove a theorem about how Polishchuk's operator D
lifts to the tautological subalgebra of Chow(J).
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 21:08:33 GMT"
},
{
"version": "v2",
"created": "Mon, 9 Jul 2007 12:55:39 GMT"
}
] | 2007-07-09T00:00:00 | [
[
"Moonen",
"Ben",
""
]
] |
0706.3479 | David Love | David Love | Hypocomputation | 34 pages | null | null | null | cs.OH | null | Hypercomputational formal theories will, clearly, be both structurally and
foundationally different from the formal theories underpinning computational
theories. However, many of the maps that might guide us into this strange realm
have been lost. So little work has been done recently in the area of
metamathematics, and so many of the previous results have been folded into
other theories, that we are in danger of loosing an appreciation of the broader
structure of formal theories. As an aid to those looking to develop
hypercomputational theories, we will briefly survey the known landmarks both
inside and outside the borders of computational theory. We will not focus in
this paper on why the structure of formal theory looks the way it does. Instead
we will focus on what this structure looks like, moving from hypocomputational,
through traditional computational theories, and then beyond to
hypercomputational theories.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 21:13:43 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Love",
"David",
""
]
] |
0706.3480 | Soheil Mohajer | Soheil Mohajer and Ali Kakhbod | Tight Bounds on the Average Length, Entropy, and Redundancy of
Anti-Uniform Huffman Codes | 9 pages, 2 figures | IET Communications, vol. 5, no. 9, pp. 1213-1219, 2011 | null | null | cs.IT math.IT | null | In this paper we consider the class of anti-uniform Huffman codes and derive
tight lower and upper bounds on the average length, entropy, and redundancy of
such codes in terms of the alphabet size of the source. The Fibonacci
distributions are introduced which play a fundamental role in AUH codes. It is
shown that such distributions maximize the average length and the entropy of
the code for a given alphabet size. Another previously known bound on the
entropy for given average length follows immediately from our results.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 21:18:36 GMT"
}
] | 2012-07-27T00:00:00 | [
[
"Mohajer",
"Soheil",
""
],
[
"Kakhbod",
"Ali",
""
]
] |
0706.3481 | Martin Houde | Martin Houde (1) and John E. Vaillancourt (2) ((1) The University of
Western Ontario, (2) California Institute of Technology) | Astronomical Image Processing with Array Detectors | 31 pages, 5 figures, accepted for publication in the PASP | PASP 2007 (August), 119, 871 | 10.1086/521109 | null | astro-ph | null | We address the question of astronomical image processing from data obtained
with array detectors. We define and analyze the cases of evenly, regularly, and
irregularly sampled maps for idealized (i.e., infinite) and realistic (i.e.,
finite) detectors. We concentrate on the effect of interpolation on the maps,
and the choice of the kernel used to accomplish this task. We show how the
normalization intrinsic to the interpolation process must be carefully
accounted for when dealing with irregularly sampled grids. We also analyze the
effect of missing or dead pixels in the array, and their consequences for the
Nyquist sampling criterion.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 21:36:19 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Houde",
"Martin",
""
],
[
"Vaillancourt",
"John E.",
""
]
] |
0706.3482 | Christopher J. Conselice | Christopher J. Conselice | The Assembly History of Massive Galaxies: What Do We Know? | Invited review, 12 pages, to appear in "Pathways through an eclectic
Universe", J. H. Knapen, T. J. Mahoney, and A. Vazdekis (Eds.), ASP Conf.
Ser., 2007 | null | null | null | astro-ph | null | Understanding the formation history of massive galaxies is one of most
popular and longstanding problems in astronomy, with observations and theory
addressing how and when these systems assembled. Since the most massive
galaxies in today's universe, with M_*> 10^11 M_0, are nearly all elliptical
with uniform old stellar populations, we must probe higher redshifts to
discover their full origins. A recent consensus has developed that nearly all
M_* > 10^11 M_0 galaxies we see today were established by z~1, with at most a
factor of two growth in stellar mass and number densities at lower redshifts.
We review the evidence for this, and discuss how recent observations of star
formation rates, colors, and morphologies of massive galaxies at z < 1 with M_*
> 10^11 M_0 show that these systems are still experiencing some evolution.
Massive galaxies undergo on average a single major merger at z < 1.5, and
roughly half are experiencing star formation at the same redshifts. The highest
mass galaxies, with M_* > 10^11.5 M_0, appear in similar abundance at z < 2,
suggesting that extremely massive galaxies are mostly formed very early in the
universe. Observations at z > 1.5 demonstrate that major galaxy mergers are the
primary method for assembling these massive galaxies, with nearly all of this
merging occurring at z > 2, with on average 4 to 5 major mergers taking place
at z = 1.5 - 3.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 21:43:05 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Conselice",
"Christopher J.",
""
]
] |
0706.3483 | Michael Eichmair | Michael Eichmair | The size of isoperimetric surfaces in 3-manifolds and a rigidity result
for the upper hemisphere | 9 pages. Thoroughly revised final version. Comments welcome! | null | null | null | math.DG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We characterize the standard $\mathbb{S}^3$ as the closed Ricci-positive
3-manifold with scalar curvature at least 6 having isoperimetric surfaces of
largest area: $4\pi$. As a corollary we answer in the affirmative an
interesting special case of a conjecture of Min-Oo's on the scalar curvature
rigidity of the upper hemisphere..
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 18:00:17 GMT"
},
{
"version": "v2",
"created": "Mon, 2 Jul 2007 22:09:52 GMT"
},
{
"version": "v3",
"created": "Wed, 19 Nov 2008 14:57:24 GMT"
},
{
"version": "v4",
"created": "Sun, 7 Jun 2009 19:56:11 GMT"
}
] | 2009-06-08T00:00:00 | [
[
"Eichmair",
"Michael",
""
]
] |
0706.3484 | Schoeffel Laurent | L. Schoeffel (DAPNIA, Saclay) | Diffraction at HERA and implications for Tevatron and LHC | 4 pages, 3 figures, proceedings of the XIIth international conference
on Elastic and Diffractive Scattering (Hambourg) 21-25 may 2007 | null | null | null | hep-ph | null | We describe new QCD fits to diffractive cross sections measured at HERA and
we use the parton densities derived from these fits to predict the shape of the
dijet mass fraction in double Pomeron exchange at the Tevatron. We discuss the
existence of exclusive events in this dijet channel and some prospects are
given for the LHC.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 23:20:21 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 12:46:10 GMT"
},
{
"version": "v3",
"created": "Sun, 8 Jul 2007 06:06:43 GMT"
},
{
"version": "v4",
"created": "Sat, 21 Jul 2007 06:48:06 GMT"
}
] | 2007-07-21T00:00:00 | [
[
"Schoeffel",
"L.",
"",
"DAPNIA, Saclay"
]
] |
0706.3485 | Boaz Katz | Boaz Katz, Eli Waxman | In which shell-type SNRs should we look for gamma-rays and neutrinos
from p-p collisions? | 13 pages, 1 figure, accepted for publication in JCAP, minor revisions | JCAP0801:018,2008 | 10.1088/1475-7516/2008/01/018 | null | astro-ph | null | We present a simple analytic model for the various contributions to the
non-thermal emission from shell type SNRs, and show that this model's results
reproduce well the results of previous detailed calculations. We show that the
\geq 1 TeV gamma ray emission from the shell type SNRs RX J1713.7-3946 and RX
J0852.0-4622 is dominated by inverse-Compton scattering of CMB photons (and
possibly infra-red ambient photons) by accelerated electrons. Pion decay (due
to proton-proton collisions) is shown to account for only a small fraction,
\lesssim10^-2, of the observed flux, as assuming a larger fractional
contribution would imply nonthermal radio and X-ray synchrotron emission and
thermal X-ray Bremsstrahlung emission that far exceed the observed radio and
X-ray fluxes. Models where pion decay dominates the \geq 1 TeV flux avoid the
implied excessive synchrotron emission (but not the implied excessive thermal
X-ray Bremsstrahlung emission) by assuming an extremely low efficiency of
electron acceleration, K_ep \lesssim 10^-4 (K_ep is the ratio of the number of
accelerated electrons and the number of accelerated protons at a given energy).
We argue that observations of SNRs in nearby galaxies imply a lower limit of
K_ep \gtrsim 10^-3, and thus rule out K_ep values \lesssim 10^-4 (assuming that
SNRs share a common typical value of K_ep). It is suggested that SNRs with
strong thermal X-ray emission, rather than strong non-thermal X-ray emission,
are more suitable candidates for searches of gamma rays and neutrinos resulting
from proton-proton collisions. In particular, it is shown that the neutrino
flux from the SNRs above is probably too low to be detected by current and
planned neutrino observatories (Abridged).
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 12:31:34 GMT"
},
{
"version": "v2",
"created": "Wed, 4 Jul 2007 21:00:15 GMT"
},
{
"version": "v3",
"created": "Sun, 23 Dec 2007 14:27:01 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Katz",
"Boaz",
""
],
[
"Waxman",
"Eli",
""
]
] |
0706.3486 | Stephanie van Willigenburg | Louis J. Billera, Samuel K. Hsiao and Stephanie van Willigenburg | Peak Quasisymmetric Functions and Eulerian Enumeration | 23 pages; final version | Adv. Math. 176: 248--276 (2003) | null | null | math.CO | null | Via duality of Hopf algebras, there is a direct association between peak
quasisymmetric functions and enumeration of chains in Eulerian posets. We study
this association explicitly, showing that the notion of $\cd$-index, long
studied in the context of convex polytopes and Eulerian posets, arises as the
dual basis to a natural basis of peak quasisymmetric functions introduced by
Stembridge. Thus Eulerian posets having a nonnegative $\cd$-index (for example,
face lattices of convex polytopes) correspond to peak quasisymmetric functions
having a nonnegative representation in terms of this basis. We diagonalize the
operator that associates the basis of descent sets for all quasisymmetric
functions to that of peak sets for the algebra of peak functions, and study the
$g$-polynomial for Eulerian posets as an algebra homomorphism.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 00:26:41 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Billera",
"Louis J.",
""
],
[
"Hsiao",
"Samuel K.",
""
],
[
"van Willigenburg",
"Stephanie",
""
]
] |
0706.3487 | Da-jun Zhang | Qi-fei Xuan, Mei-ying Ou, Da-jun Zhang | Wronskian solutions to the KdV equation via B\"acklund transformation | 16 pages | null | null | null | nlin.SI | null | In the paper we discuss the B\"acklund transformation of the KdV equation
between solitons and solitons, between negatons and negatons, between positons
and positons, between rational solution and rational solution, and between
complexitons and complexitons. We investigate the conditions that Wronskian
entries satisfy for the bilinear B\"acklund transformation of the KdV equation.
By choosing suitable Wronskian entries and the parameter in the bilinear
B\"acklund transformation, we obtain transformations between many kinds of
solutions.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 00:52:09 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Xuan",
"Qi-fei",
""
],
[
"Ou",
"Mei-ying",
""
],
[
"Zhang",
"Da-jun",
""
]
] |
0706.3488 | Schoeffel Laurent | L. Schoeffel (DAPNIA, Saclay) | Generalised parton distributions at HERA and prospects for COMPASS | 8 pages, 5 figures, submitted to Phys. Lett. B | Phys.Lett.B658:33-39,2007 | 10.1016/j.physletb.2007.10.036 | null | hep-ph | null | We present a model of generalised parton distributions based on a forward
ansatz in the DGLAP region. We discuss some aspects of the parametrisations, as
the dependence in t, with factorised and non-factorised approaches, where t is
the square of the four-momentum exchanged at the hadron vertex. The predictions
of this model are then compared with DVCS cross sections from H1 and ZEUS, and
a related observable, the skewing factor, defined as the following ratio
imaginary amplitudes : $R \equiv {Im {\cal A} (\gamma^*+p \to \gamma
+p)\lfrestriction{t=0}} / {Im {\cal A} (\gamma^*+p \to \gamma^*
+p)\lfrestriction{t=0}}$. It is an interesting quantity including both the
non-forward kinematics and the non-diagonal effects. Finally, we discuss the
beam charge asymmetry, which is certainly the most sensitive observable to the
different hypothesis needed in the GPDs parametrisations. We show that the
approximations done for the t dependence lead to significant differences for
the predictions in the HERMES kinematic domain and prospects are given for
COMPASS.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 02:17:01 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 14:22:49 GMT"
},
{
"version": "v3",
"created": "Tue, 10 Jul 2007 10:42:24 GMT"
},
{
"version": "v4",
"created": "Fri, 3 Aug 2007 09:24:40 GMT"
},
{
"version": "v5",
"created": "Sat, 4 Aug 2007 07:52:48 GMT"
},
{
"version": "v6",
"created": "Tue, 16 Oct 2007 08:57:10 GMT"
},
{
"version": "v7",
"created": "Thu, 18 Oct 2007 10:02:53 GMT"
}
] | 2010-03-25T00:00:00 | [
[
"Schoeffel",
"L.",
"",
"DAPNIA, Saclay"
]
] |
0706.3489 | Hideo Hasegawa | Hiode Hasegawa (Tokyo Gakugei Univ.) | Information on mean, fluctuation and synchrony conveyed by a population
of firing neurons | 26 pages, 10 figures, revised the manuscript | null | null | null | cond-mat.dis-nn | null | A population of firing neurons is expected to carry not only mean firing rate
but also its fluctuation and synchrony among neurons. In order to examine this
possibility, we have studied responses of neuronal ensembles to three kinds of
inputs: mean-, fluctuation- and synchrony-driven inputs. The generalized
rate-code model including additive and multiplicative noise (H. Hasegawa, Phys.
Rev. E {\bf 75}, 051904 (2007)) has been studied by direct simulations (DSs)
and the augmented moment method (AMM) in which equations of motion for mean
firing rate, fluctuation and synchrony are derived. Results calculated by the
AMM are in good agreement with those by DSs. The independent component analysis
(ICA) of our results has shown that mean firing rate, fluctuation (or
variability) and synchrony may carry independent information in the population
rate-code model. The input-output relation of mean firing rates is shown to
have higher sensitivity for larger multiplicative noise, as recently observed
in prefrontal cortex. A comparison is made between results obtained by the
integrate-and-fire (IF) model and our rate-code model. The relevance of our
results to experimentally obtained data is also discussed.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 09:23:15 GMT"
},
{
"version": "v2",
"created": "Thu, 28 Jun 2007 00:42:41 GMT"
},
{
"version": "v3",
"created": "Tue, 28 Aug 2007 21:26:22 GMT"
},
{
"version": "v4",
"created": "Mon, 18 Feb 2008 19:35:34 GMT"
}
] | 2008-02-18T00:00:00 | [
[
"Hasegawa",
"Hiode",
"",
"Tokyo Gakugei Univ."
]
] |
0706.3490 | Lujun Fang | Zhongzhi Zhang, Shuigeng Zhou, Lujun Fang, Jihong Guan, Yichao Zhang | Maximal planar scale-free Sierpinski networks with small-world effect
and power-law strength-degree correlation | 6 pages, 5 figures, accepted by EPL | EPL,79(2007)38007 | 10.1209/0295-5075/79/38007 | null | physics.soc-ph | null | Many real networks share three generic properties: they are scale-free,
display a small-world effect, and show a power-law strength-degree correlation.
In this paper, we propose a type of deterministically growing networks called
Sierpinski networks, which are induced by the famous Sierpinski fractals and
constructed in a simple iterative way. We derive analytical expressions for
degree distribution, strength distribution, clustering coefficient, and
strength-degree correlation, which agree well with the characterizations of
various real-life networks. Moreover, we show that the introduced Sierpinski
networks are maximal planar graphs.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 04:22:56 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Zhang",
"Zhongzhi",
""
],
[
"Zhou",
"Shuigeng",
""
],
[
"Fang",
"Lujun",
""
],
[
"Guan",
"Jihong",
""
],
[
"Zhang",
"Yichao",
""
]
] |
0706.3491 | Lujun Fang | Zhongzhi Zhang, Lichao Chen, Shuigeng Zhou, Lujun Fang, Jihong Guan,
Tao Zou | Exact analytical solution of average path length for Apollonian networks | 8 pages, 4 figures | Phys. Rev. E 77, 017102 (2008) | 10.1103/PhysRevE.77.017102 | null | cond-mat.stat-mech physics.soc-ph | null | The exact formula for the average path length of Apollonian networks is
found. With the help of recursion relations derived from the self-similar
structure, we obtain the exact solution of average path length, $\bar{d}_t$,
for Apollonian networks. In contrast to the well-known numerical result
$\bar{d}_t \propto (\ln N_t)^{3/4}$ [Phys. Rev. Lett. \textbf{94}, 018702
(2005)], our rigorous solution shows that the average path length grows
logarithmically as $\bar{d}_t \propto \ln N_t$ in the infinite limit of network
size $N_t$. The extensive numerical calculations completely agree with our
closed-form solution.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 04:35:30 GMT"
},
{
"version": "v2",
"created": "Thu, 31 Jan 2008 14:14:44 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zhang",
"Zhongzhi",
""
],
[
"Chen",
"Lichao",
""
],
[
"Zhou",
"Shuigeng",
""
],
[
"Fang",
"Lujun",
""
],
[
"Guan",
"Jihong",
""
],
[
"Zou",
"Tao",
""
]
] |
0706.3492 | Takashi Hotta | Takashi Hotta | Multipole State of Heavy Lanthanide Filled Skutterudites | 5 pages, 3 figures | J. Phys. Soc. Jpn. 76, 083705 (2007). | 10.1143/JPSJ.76.083705 | null | cond-mat.str-el | null | We discuss multipole properties of filled skutterudites containing heavy
lanthanide Ln from a microscopic viewpoint on the basis of a seven-orbital
Anderson model. For Ln=Gd, in contrast to naive expectation, quadrupole moments
remain in addition to main dipole ones. For Ln=Ho, we find an exotic state
governed by octupole moment. For Ln=Tb and Tm, no significant multipole moments
appear at low temperatures, while for Ln=Dy, Er, and Yb, dipole and
higher-order multipoles are dominant. We briefly discuss possible relevance of
these multipole states with actual materials.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 04:36:39 GMT"
}
] | 2009-11-16T00:00:00 | [
[
"Hotta",
"Takashi",
""
]
] |
0706.3493 | Takayuki Shirakura | T. Shirakura, D. Ninomiya, Y. Iyama, and F. Matsubara | Gabay-Toulouse Phase Transition in Heisenberg Spin-Glasses in Three
Dimensions | 4 pages, 7 figures | null | null | null | cond-mat.dis-nn | null | We examine three-dimensional $\pm J$ Heisenberg models with and without
random anisotropies in a magnetic field. We calculate both the stiffness
exponent $\theta_s$ at absolute zero temperature and spin-glass correlation
lengths for the longitudinal and transverse spin components at finite
temperatures. We suggest that, contrary to a chirality scenario predicted by
Kawamura and his co-workers, a Gabay-Toulouse phase transition occurs when the
anisotropies are absent, although no phase transition occurs when they are
present.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 05:02:08 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Shirakura",
"T.",
""
],
[
"Ninomiya",
"D.",
""
],
[
"Iyama",
"Y.",
""
],
[
"Matsubara",
"F.",
""
]
] |
0706.3494 | Aleksandr I. Sokolov | A. I. Sokolov | Two-dimensional phase transition models and \lambda \phi^4 field theory | 13 pages, 7 tables, to appear in J. Phys. Studies 10, No 4 (2006) | J.Phys.Stud.10:351-357,2006 | null | null | cond-mat.stat-mech hep-lat hep-ph hep-th | null | The overview is given of the results obtained recently in the course of
renormalization-group (RG) study of two-dimensional (2D) models. RG functions
of the two-dimensional n-vector \lambda \phi^4 Euclidean field theory are
written down up to the five-loop terms and perturbative series are resummed by
the Pade-Borel-Leroy techniques. An account for the five-loop term is shown to
shift the Wilson fixed point only briefly, leaving it outside the segment
formed by the results of the lattice calculations. This is argued to reflect
the influence of the non-analytical contribution to the \beta-function. The
evaluation of the critical exponents for n = 1, n = 0 and n = -1 in the
five-loop approximation and comparison of the results with known exact values
confirm the conclusion that non-analytical contributions are visible in two
dimensions. The estimates obtained on the base of pseudo-\epsilon expansions
originating from the 5-loop 2D RG series are also discussed.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 05:48:25 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Sokolov",
"A. I.",
""
]
] |
0706.3495 | Yudai Suwa Dr. | Yudai Suwa, Tomoya Takiwaki, Kei Kotake, Katsuhiko Sato | Gravitational Wave Background from Population III Stars | 4 pages, 3 figures, accepted for publication in ApJL | AIP Conf.Proc.990:142-144,2008; Astrophys.J.665:L43-L46,2007 | 10.1063/1.2905522 10.1086/521078 | UTAP-581, RESCEU-79/07 | astro-ph | null | We estimate the gravitational wave (GW) background from Population III (Pop
III) stars using the results from our hydrodynamic simulations (Suwa et al.
2007). We calculate gravitational waveforms from matter motions and anisotropic
neutrino emissions for single Pop III stars. We find that the GW amplitudes
from matter motions are dominant until just after bounce, but those from
neutrinos dominate later on at frequencies below $\sim 10$ Hz in the GW
spectrum. Computing the overall signal produced by the ensemble of such Pop III
stars, we find that the resultant density parameter of the GW background peaks
at the amplitude of $\Omega_\mathrm{GW}\sim 10^{-10}$ in the frequency interval
$\sim 1-10$ Hz. We show that such signals, depending on the formation rate of
Pop III stars, can be within the detection limits of future planned
interferometers such as DECIGO and BBO in the frequency interval of $\sim
0.1-1$ Hz. Our results suggest that the detection of the GW background from Pop
III stars can be an important tool to supply the information about the star
formation history in the early universe.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 05:58:40 GMT"
}
] | 2010-11-11T00:00:00 | [
[
"Suwa",
"Yudai",
""
],
[
"Takiwaki",
"Tomoya",
""
],
[
"Kotake",
"Kei",
""
],
[
"Sato",
"Katsuhiko",
""
]
] |
0706.3496 | Makiko Nio | T. Aoyama, M. Hayakawa, T. Kinoshita, and M. Nio | Revised value of the eighth-order electron g-2 | 4 pages, 1 figure, typo is corrected | Phys.Rev.Lett.99:110406,2007 | 10.1103/PhysRevLett.99.110406 | null | hep-ph | null | The contribution to the eighth-order anomalous magnetic moment (g-2) of the
electron from a set of diagrams without closed lepton loops is recalculated
using a new FORTRAN code generated by an automatic code generator. Comparing
the contributions of individual diagrams of old and new calculations, we found
an inconsistency in the old treatment of infrared subtraction terms in two
diagrams. Correcting this error leads to the revised value -1.9144 (35)
(alpha/pi)^4 for the eighth-order term. This theoretical change induces the
shift of the inverse of the fine structure constant by -6.41180(73)x10^{-7}.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 08:11:04 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 01:50:47 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Aoyama",
"T.",
""
],
[
"Hayakawa",
"M.",
""
],
[
"Kinoshita",
"T.",
""
],
[
"Nio",
"M.",
""
]
] |
0706.3497 | Wen Hui Long | Wen Hui Long, Hiroyuki Sagawa, Nguyen Van Giai, and Jie Meng | Shell Structure and $\rho$-Tensor Correlations in Density-Dependent
Relativistic Hartree-Fock theory | 20 pages, 11 figures, 6 tables | Phys.Rev.C76:034314,2007 | 10.1103/PhysRevC.76.034314 | null | nucl-th | null | A new effective interaction PKA1 with $\rho$-tensor couplings for the
density-dependent relativistic Hartree-Fock (DDRHF) theory is presented. It is
obtained by fitting selected empirical ground state and shell structure
properties. It provides satisfactory descriptions of nuclear matter and the
ground state properties of finite nuclei at the same quantitative level as
recent DDRHF and RMF models. Significant improvement on the single-particle
spectra is also found due to the inclusion of $\rho$-tensor couplings. As a
result, PKA1 cures a common disease of the existing DDRHF and RMF Lagrangians,
namely the artificial shells at 58 and 92, and recovers the realistic sub-shell
closure at 64. Moreover, the proper spin-orbit splittings and well-conserved
pseudo-spin symmetry are obtained with the new effective interaction PKA1. Due
to the extra binding introduced by the $\rho$-tensor correlations, the balance
between the nuclear attractions and the repulsions is changed and this
constitutes the physical reason for the improvement of the nuclear shell
structure.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 06:03:28 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Long",
"Wen Hui",
""
],
[
"Sagawa",
"Hiroyuki",
""
],
[
"Van Giai",
"Nguyen",
""
],
[
"Meng",
"Jie",
""
]
] |
0706.3498 | Jihn E. Kim | Jihn E. Kim | Z_{12-I} Orbifold Compactification toward SUSY Standard Model | 13 pages with 5 figure. Talk presented at "CTP Symposium on SUSY at
LHC", Cairo, 11-14 March 2007 | Int.J.Mod.Phys.A22:5609-5621,2007 | 10.1142/S0217751X07038876 | null | hep-ph | null | We explain the orbifold compactification in string models and present a
Z_{12-I} orbifold compactification toward supersymmetric standard models. We
also point out an effective R-parity from this string construction. The VEVs of
gauge singlets are chosen such that phenomenological constraints are satisfied.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 06:32:20 GMT"
}
] | 2010-11-03T00:00:00 | [
[
"Kim",
"Jihn E.",
""
]
] |
0706.3499 | Bharath Sriperumbudur | Bharath K. Sriperumbudur and Gert R. G. Lanckriet | Metric Embedding for Nearest Neighbor Classification | 9 pages, 1 table | null | null | null | stat.ML | null | The distance metric plays an important role in nearest neighbor (NN)
classification. Usually the Euclidean distance metric is assumed or a
Mahalanobis distance metric is optimized to improve the NN performance. In this
paper, we study the problem of embedding arbitrary metric spaces into a
Euclidean space with the goal to improve the accuracy of the NN classifier. We
propose a solution by appealing to the framework of regularization in a
reproducing kernel Hilbert space and prove a representer-like theorem for NN
classification. The embedding function is then determined by solving a
semidefinite program which has an interesting connection to the soft-margin
linear binary support vector machine classifier. Although the main focus of
this paper is to present a general, theoretical framework for metric embedding
in a NN setting, we demonstrate the performance of the proposed method on some
benchmark datasets and show that it performs better than the Mahalanobis metric
learning algorithm in terms of leave-one-out and generalization errors.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 06:50:24 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Sriperumbudur",
"Bharath K.",
""
],
[
"Lanckriet",
"Gert R. G.",
""
]
] |
0706.3500 | Sourav Chatterjee | Sourav Chatterjee | Spin glasses and Stein's method | 29 pages. Final version. To appear in PTRF | null | null | null | math.PR math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We introduce some applications of Stein's method in the high temperature
analysis of spin glasses. Stein's method allows the direct analysis of the
Gibbs measure without having to create a cavity. Another advantage is that it
gives limit theorems with total variation error bounds, although the bounds can
be suboptimal. A surprising byproduct of our analysis is a relatively
transparent explanation of the Thouless-Anderson-Palmer system of equations.
Along the way, we develop Stein's method for mixtures of two Gaussian
densities.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 06:57:31 GMT"
},
{
"version": "v2",
"created": "Sun, 25 Nov 2007 08:04:53 GMT"
},
{
"version": "v3",
"created": "Sun, 2 Aug 2009 10:16:06 GMT"
}
] | 2009-08-02T00:00:00 | [
[
"Chatterjee",
"Sourav",
""
]
] |
0706.3501 | Moire Prescott | Moire K. M. Prescott (1), Robert C. Kennicutt Jr. (2 and 1), George J.
Bendo (3 and 1), Brent A. Buckalew (4), Daniela Calzetti (6 and 5), Charles
W. Engelbracht (1), Karl D. Gordon (1), David J. Hollenbach (7), Janice C.
Lee (8 and 1), John Moustakas (9), Daniel A. Dale (10), George Helou (4),
Thomas H. Jarrett (4), Eric J. Murphy (11), John-David T. Smith (1), Sanae
Akiyama (1), Megan L. Sosey (5) ((1) Steward Observatory, University of
Arizona, (2) Institute of Astronomy, University of Cambridge, (3)
Astrophysics Group, Imperial College, (4) Caltech, IPAC, (5) Space Telescope
Science Institute, (6) Department of Astronomy, University of Massachussetts,
(7) NASA/Ames Research Center, (8) National Optical Astronomy Observatory,
(9) Department of Physics, New York University, (10) Department of Physics
and Astronomy, University of Wyoming, (11) Department of Astronomy, Yale
University) | The Incidence of Highly-Obscured Star-Forming Regions in SINGS Galaxies | Accepted for publication in ApJ; emulateapj style, 30 pages, 18
figures (compressed versions), 3 tables | Astrophys.J. 668 (2007) 182-202 | 10.1086/521071 | null | astro-ph | null | Using the new capabilities of the Spitzer Space Telescope and extensive
multiwavelength data from the Spitzer Infrared Nearby Galaxies Survey (SINGS),
it is now possible to study the infrared properties of star formation in nearby
galaxies down to scales equivalent to large HII regions. We are therefore able
to determine what fraction of large, infrared-selected star-forming regions in
normal galaxies are highly obscured and address how much of the star formation
we miss by relying solely on the optical portion of the spectrum. Employing a
new empirical method for deriving attenuations of infrared-selected
star-forming regions we investigate the statistics of obscured star formation
on 500pc scales in a sample of 38 nearby galaxies. We find that the median
attenuation is 1.4 magnitudes in H-alpha and that there is no evidence for a
substantial sub-population of uniformly highly-obscured star-forming regions.
The regions in the highly-obscured tail of the attenuation distribution
(A_H-alpha > 3) make up only ~4% of the sample of nearly 1800 regions, though
very embedded infrared sources on the much smaller scales and lower
luminosities of compact and ultracompact HII regions are almost certainly
present in greater numbers. The highly-obscured cases in our sample are
generally the bright, central regions of galaxies with high overall attenuation
but are not otherwise remarkable. We also find that a majority of the galaxies
show decreasing radial trends in H-alpha attenuation. The small fraction of
highly-obscured regions seen in this sample of normal, star-forming galaxies
suggests that on 500pc scales the timescale for significant dispersal or break
up of nearby, optically-thick dust clouds is short relative to the lifetime of
a typical star-forming region.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 07:45:05 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Prescott",
"Moire K. M.",
"",
"2 and 1"
],
[
"Kennicutt",
"Robert C.",
"Jr.",
"2 and 1"
],
[
"Bendo",
"George J.",
"",
"3 and 1"
],
[
"Buckalew",
"Brent A.",
"",
"6 and 5"
],
[
"Calzetti",
"Daniela",
"",
"6 and 5"
],
[
"Engelbracht",
"Charles W.",
"",
"8 and 1"
],
[
"Gordon",
"Karl D.",
"",
"8 and 1"
],
[
"Hollenbach",
"David J.",
"",
"8 and 1"
],
[
"Lee",
"Janice C.",
"",
"8 and 1"
],
[
"Moustakas",
"John",
""
],
[
"Dale",
"Daniel A.",
""
],
[
"Helou",
"George",
""
],
[
"Jarrett",
"Thomas H.",
""
],
[
"Murphy",
"Eric J.",
""
],
[
"Smith",
"John-David T.",
""
],
[
"Akiyama",
"Sanae",
""
],
[
"Sosey",
"Megan L.",
""
]
] |
0706.3502 | P Vijay Kumar | Petros Elia and P. Vijay Kumar | Approximately-Universal Space-Time Codes for the Parallel, Multi-Block
and Cooperative-Dynamic-Decode-and-Forward Channels | null | null | null | null | cs.IT cs.DM cs.NI math.IT | null | Explicit codes are constructed that achieve the diversity-multiplexing gain
tradeoff of the cooperative-relay channel under the dynamic decode-and-forward
protocol for any network size and for all numbers of transmit and receive
antennas at the relays.
A particularly simple code construction that makes use of the Alamouti code
as a basic building block is provided for the single relay case.
Along the way, we prove that space-time codes previously constructed in the
literature for the block-fading and parallel channels are approximately
universal, i.e., they achieve the DMT for any fading distribution. It is shown
how approximate universality of these codes leads to the first DMT-optimum code
construction for the general, MIMO-OFDM channel.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 07:47:57 GMT"
},
{
"version": "v2",
"created": "Fri, 13 Jul 2007 12:43:51 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Elia",
"Petros",
""
],
[
"Kumar",
"P. Vijay",
""
]
] |
0706.3503 | Yoshiko Kanada-En'yo | Yoshiko Kanada-En'yo, Yusuke Kawanami, Yasutaka Taniguchi, and Masaaki
Kimura | Largely deformed states of $^{13}$B | 4 figures, submitted to Phys. Rev. C | null | null | null | nucl-th | null | The excited states of $^{13}$B were studied with a method of antisymmetrized
molecular dynamics(AMD). The theoretical results suggest that the intruder
states with large deformations construct the rotational bands, $K^\pi=3/2^-$
and $K^\pi=1/2^+$, starting from 5 MeV and 8 MeV, respectively. The neutron
structure of the $K^\pi=3/2^-$ is analogous to the intruder ground state of
$^{12}$Be. In the predicted $K^\pi=1/2^+$ band, we found very exotic structure
with a proton intruder configuration. This proton intruder state has a larger
deformation than superdeformation. The band-head $1/2^+$ state is assigned to
the $1/2^+$(4.83 MeV), which was experimentally suggested to be the proton
intruder state because of the strong production via the proton-transfer to the
$^{12}$Be($0^+$) state in the $^4$He($^{12}$Be,$^{13}$B$\gamma$)$X$
experiments.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 08:08:15 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Kanada-En'yo",
"Yoshiko",
""
],
[
"Kawanami",
"Yusuke",
""
],
[
"Taniguchi",
"Yasutaka",
""
],
[
"Kimura",
"Masaaki",
""
]
] |
0706.3504 | Qi-Ren Zhang | Qi-Ren Zhang | Axiomatic Foundations for the Principle of Entropy Increase | 8 pages | Int. J. Mod. Phys. E17(2008) 1075-1082 | 10.1142/S0218301308010362 | null | physics.class-ph | null | We show that the principle of entropy increase may be exactly founded on a
few axioms valid not only for quantum and classical statistics, but also for a
wide range of statistical processes.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 09:07:20 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Aug 2007 01:25:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zhang",
"Qi-Ren",
""
]
] |
0706.3505 | Dariush Latifi | Dariush Latifi, Asadollah Razavi | A symmetric Finsler space with Chern connection | null | null | null | null | math.DG | null | We define a symmetry for a Finsler space with Chern connection and
investigate its implementation and properties and find a relation between them
and flag curvature.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 09:10:14 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Latifi",
"Dariush",
""
],
[
"Razavi",
"Asadollah",
""
]
] |
0706.3506 | Oren Shafir | Amit Keren, Oren Shafir, Efrat Shimshoni, Valerie Marvaud, Anne
Bachschmidt, Jerome Long | Experimental Estimates of Dephasing Time in Molecular Magnets | 10 pages, 3 figures | Phys. Rev. Lett. 98, 257204 (2007) | 10.1103/PhysRevLett.98.257204 | null | cond-mat.str-el | null | Muon spin relaxation measurements in isotropic molecular magnets (MM) with a
spin value S ranging from 7/2 to 27/2 are used to determine the magnitude and
origin of dephasing time $\tau_\phi$ of molecular magnets. It is found that
$\tau_\phi$ ~ 10 nsec with no S or ligand dependence. This indicates a nuclear
origin for the stochastic field. Since $\tau_\phi$ is a property of the
environment, we argue that it is a number common to similar types of MM.
Therefore, $\tau_\phi$ is shorter than the Zener and tunneling times of
anisotropic MM such as Fe8 or Mn4 for standard laboratory sweep rates. Our
findings call for a stochastic Landau-Zener theory in this particular case.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 10:03:57 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 07:35:40 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Keren",
"Amit",
""
],
[
"Shafir",
"Oren",
""
],
[
"Shimshoni",
"Efrat",
""
],
[
"Marvaud",
"Valerie",
""
],
[
"Bachschmidt",
"Anne",
""
],
[
"Long",
"Jerome",
""
]
] |
0706.3507 | Yair Goldfarb | Yair Goldfarb and David J Tannor | Interference in Bohmian Mechanics with Complex Action | null | null | 10.1063/1.2794029 | null | quant-ph | null | In recent years, intensive effort has gone into developing numerical tools
for exact quantum mechanical calculations that are based on Bohmian mechanics.
As part of this effort we have recently developed as alternative formulation of
Bohmian mechanics in which the quantum action, S, is taken to be complex [JCP
{125}, 231103 (2006)]. In the alternative formulation there is a significant
reduction in the magnitude of the quantum force as compared with the
conventional Bohmian formulation, at the price of propagating complex
trajectories. In this paper we show that Bohmian mechanics with complex action
is able to overcome the main computational limitation of conventional Bohmian
methods -- the propagation of wavefunctions once nodes set in. In the vicinity
of nodes, the quantum force in conventional Bohmian formulations exhibits rapid
oscillations that pose severe difficulties for existing numerical schemes. We
show that within complex Bohmian mechanics, multiple complex initial conditions
can lead to the same real final position, allowing for the description of nodes
as a sum of the contribution from two or more crossing trajectories. The idea
is illustrated on the reflection amplitude from a one-dimensional Eckart
barrier. We believe that trajectory crossing, although in contradiction to the
conventional Bohmian trajectory interpretation, provides an important new tool
for dealing with the nodal problem in Bohmian methods.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 10:08:52 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Goldfarb",
"Yair",
""
],
[
"Tannor",
"David J",
""
]
] |
0706.3508 | Yair Goldfarb | Yair Goldfarb, Jeremy Schiff and David J Tannor | Unified derivation of Bohmian methods and the incorporation of
interference effects | null | null | null | null | quant-ph | null | We present a unified derivation of Bohmian methods that serves as a common
starting point for the derivative propagation method (DPM), Bohmian mechanics
with complex action (BOMCA) and the zero-velocity complex action method
(ZEVCA). The unified derivation begins with the ansatz
$\psi=e^{\frac{iS}{\hbar}}$ where the action, $S$, is taken to be complex and
the quantum force is obtained by writing a hierarchy of equations of motion for
the phase partial derivatives. We demonstrate how different choices of the
trajectory velocity field yield different formulations such as DPM, BOMCA and
ZEVCA. The new derivation is used for two purposes. First, it serves as a
common basis for comparing the role of the quantum force in the DPM and BOMCA
formulations. Second, we use the new derivation to show that superposing the
contributions of real, crossing trajectories yields a nodal pattern essentially
identical to that of the exact quantum wavefunction. The latter result suggests
a promising new approach to deal with the challenging problem of nodes in
Bohmian mechanics.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 10:19:07 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Goldfarb",
"Yair",
""
],
[
"Schiff",
"Jeremy",
""
],
[
"Tannor",
"David J",
""
]
] |
0706.3509 | Egle Tomasi-Gustafsson | C. Adamu\v{s}\v{c}\'in, E. Tomasi-Gustafsson, E. Santopinto and R.
Bijker | Two-component model for the axial form factor of the nucleon | 12 pages 2 figures Final version to appear in Phys. Rev. C | Phys.Rev.C78:035201,2008 | 10.1103/PhysRevC.78.035201 | null | nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The axial form factor of the nucleon is studied in a two-component model
consisting of a three-quark intrinsic structure surrounded by a meson cloud.
The experimental data in the space-like region are well reproduced with a
minimal number of parameters. The results are similar to those obtained from a
dipole fit up to 1 GeV$^2$, but they surprisingly show a zero between 2 and 3
GeV$^2$. Such behavior, predicted by the present model completely disagrees
with the dipole parametrization. The theoretical expression for the form factor
is then analytically extrapolated to the time-like region, giving the first
predictions in this regime. This kinematical region is especially interesting
for present and future colliders.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 10:48:11 GMT"
},
{
"version": "v2",
"created": "Tue, 4 Mar 2008 08:18:40 GMT"
},
{
"version": "v3",
"created": "Wed, 20 Aug 2008 10:13:51 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Adamuščín",
"C.",
""
],
[
"Tomasi-Gustafsson",
"E.",
""
],
[
"Santopinto",
"E.",
""
],
[
"Bijker",
"R.",
""
]
] |
0706.3510 | Guowen Wang | Wang Guowen | Realistic solution to the tunneling time problem | 9 pages, 6 figures | null | null | null | quant-ph | null | There remains the old question of how long a quantum particle takes to tunnel
through a potential barrier higher than its incident kinetic energy. In this
article a solution of the question is proposed on the basis of a realistic
explanation of quantum mechanics. The explanation implies that the tunneling
particle has a certain chance to borrow enough energy from self-interference to
high-jump over the barrier. The root-mean-square velocity and the effective
tunneling time of an electron tunneling through a rectangular barrier are
numerically calculated. No superluminal effect (Hartman effect) is found for
the tunneling electron. Heisenberg's energy-time uncertainty relation for the
tunneling effect is verified by calculating an introduced coefficient
representing uncertainty. The present author argues that phase time, dwell time
and B\"{u}tticker-Landauer time are not appropriate expressions for the actual
transit time in a tunneling process. A quantum high-jumping model is presented
to resolve the paradox that kinetic energy of the tunneling particle is
negative and its momentum is imaginary.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 10:51:13 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Guowen",
"Wang",
""
]
] |
0706.3511 | Vladimir Nazaikinskii | V. E. Nazaikinskii, A. Yu. Savin and B. Yu. Sternin | On elliptic differential operators with shifts | 12 pages; v2: minor improvements made | null | null | null | math.OA math.AP math.KT | null | We give an index formula for elliptic differential operators whose
coefficients include shifts forming an infinite group.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 09:45:38 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jul 2007 11:24:56 GMT"
}
] | 2007-07-26T00:00:00 | [
[
"Nazaikinskii",
"V. E.",
""
],
[
"Savin",
"A. Yu.",
""
],
[
"Sternin",
"B. Yu.",
""
]
] |
0706.3512 | Dariush Latifi | Dariush Latifi | Homogeneous geodesics in homogeneous Finsler spaces | null | null | 10.1016/j.geomphys.2006.11.004 | null | math.DG | null | In this paper, we study homogeneous geodesics in homogeneous Finsler spaces.
We first give a simple criterion that characterizes geodesic vectors. We show
that the geodesics on a Lie group, relative to a bi-invariant Finsler metric,
are the cosets of the one-parameter subgroups. The existence of infinitely many
homogeneous geodesics on compact semi-simple Lie group is established. We
introduce the notion of naturally reductive homogeneous Finsler space. As a
special case, we study homogeneous geodesics in homogeneous Randers spaces.
Finally, we study some curvature properties of homogeneous geodesics. In
particular, we prove that the S-curvature vanishes along the homogeneous
geodesics.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 11:10:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Latifi",
"Dariush",
""
]
] |
0706.3513 | Brian Tighe | B. P. Tighe and J. E. S. Socolar | Nonlinear elastic stress response in granular packings | 15 pages, 12 figures; additional discussion added at several points
in text | null | 10.1103/PhysRevE.77.031303 | null | cond-mat.soft | null | We study the nonlinear elastic response of a two-dimensional material to a
localized boundary force, with the particular goal of understanding the
differences observed between isotropic granular materials and those with
hexagonal anisotropy. Corrections to the classical Boussinesq result for the
stresses in an infinite half-space of a linear, isotropic material are
developed in a power series in inverse distance from the point of application
of the force. The breakdown of continuum theory on scales of order of the grain
size is modeled with phenomenological parameters characterizing the strengths
of induced multipoles near the point of application of the external force. We
find that the data of Geng et al. on isotropic and hexagonal packings of
photoelastic grains can be fit within this framework. Fitting the hexagonal
packings requires a choice of elastic coefficients with hexagonal anisotropy
stronger than that of a simple ball and spring model. For both the isotropic
and hexagonal cases, induced dipole and quadrupole terms produce propagation of
stresses away from the vertical direction over short distances. The scale over
which such propagation occurs is significantly enhanced by the nonlinearities
that generate hexagonal anisotropy.
| [
{
"version": "v1",
"created": "Sun, 24 Jun 2007 11:22:59 GMT"
},
{
"version": "v2",
"created": "Tue, 18 Dec 2007 15:08:12 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tighe",
"B. P.",
""
],
[
"Socolar",
"J. E. S.",
""
]
] |
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