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0706.2514
Jaroslaw Bauer
J.H. Bauer
Simple proof of gauge invariance for the S-matrix element of strong-field photoionization
The paper was initially submitted (in a previous version) on 16 October 2006 to J. Phys. A and rejected. This is the extended version (with 2 figures), which is identical to the paper published online on 12 December 2007 in Physica Scripta
Physica Scripta, vol. 77, 015303 (2008)
10.1088/0953-4075/41/18/185003
null
physics.atom-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The relationship between the length gauge (LG) and the velocity gauge (VG) exact forms of the photoionization probability amplitude is considered. Our motivation for this paper comes from applications of the Keldysh-Faisal-Reiss (KFR) theory, which describes atoms (or ions) in a strong laser field (in the nonrelativistic approach, in the dipole approximation). On the faith of a certain widely-accepted assumption, we present a simple proof that the well-known LG form of the exact photoionization (or photodetachment) probability amplitude is indeed the gauge-invariant result. In contrast, to obtain the VG form of this probability amplitude, one has to either (i) neglect the well-known Goeppert-Mayer exponential factor (which assures gauge invariance) during all the time evolution of the ionized electron or (ii) put some conditions on the vector potential of the laser field.
[ { "version": "v1", "created": "Sun, 17 Jun 2007 23:57:31 GMT" }, { "version": "v2", "created": "Wed, 17 Feb 2010 18:14:09 GMT" } ]
2015-05-13T00:00:00
[ [ "Bauer", "J. H.", "" ] ]
0706.2515
James D. Meiss
H.E. Lomel\'i, J.D. Meiss, R. Ram\'irez-Ros
Canonical Melnikov theory for diffeomorphisms
laTeX, 31 pages, 3 figures
null
10.1088/0951-7715/21/3/007
null
nlin.CD math.DS
null
We study perturbations of diffeomorphisms that have a saddle connection between a pair of normally hyperbolic invariant manifolds. We develop a first-order deformation calculus for invariant manifolds and show that a generalized Melnikov function or Melnikov displacement can be written in a canonical way. This function is defined to be a section of the normal bundle of the saddle connection. We show how our definition reproduces the classical methods of Poincar\'{e} and Melnikov and specializes to methods previously used for exact symplectic and volume-preserving maps. We use the method to detect the transverse intersection of stable and unstable manifolds and relate this intersection to the set of zeros of the Melnikov displacement.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 00:04:47 GMT" } ]
2009-11-13T00:00:00
[ [ "Lomelí", "H. E.", "" ], [ "Meiss", "J. D.", "" ], [ "Ramírez-Ros", "R.", "" ] ]
0706.2516
Bhalchandra Thatte
Bhalchandra D. Thatte and Mike Steel
Reconstructing pedigrees: a stochastic perspective
20 pages, 3 figures
null
null
null
q-bio.PE
null
A pedigree is a directed graph that describes how individuals are related through ancestry in a sexually-reproducing population. In this paper we explore the question of whether one can reconstruct a pedigree by just observing sequence data for present day individuals. This is motivated by the increasing availability of genomic sequences, but in this paper we take a more theoretical approach and consider what models of sequence evolution might allow pedigree reconstruction (given sufficiently long sequences). Our results complement recent work that showed that pedigree reconstruction may be fundamentally impossible if one uses just the degrees of relatedness between different extant individuals. We find that for certain stochastic processes, pedigrees can be recovered up to isomorphism from sufficiently long sequences.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 00:16:14 GMT" } ]
2007-06-19T00:00:00
[ [ "Thatte", "Bhalchandra D.", "" ], [ "Steel", "Mike", "" ] ]
0706.2517
Raanan Schul
Raanan Schul
Big-Pieces-of-Lipschitz-Images Implies a Sufficient Carleson Estimate in a Metric Space
4 pages. No figures. Assumes familiarity with previous work
null
null
null
math.MG math.CA
null
This note is intended to be a supplement to the bi-Lipschitz decomposition of Lipschitz maps shown in [Sch]. We show that in the case of 1-Ahlfors-regular sets, the condition of having `Big Pieces of bi-Lipschitz Images' (BPBI) is equivalent to a Carleson condition.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 00:41:33 GMT" } ]
2007-06-19T00:00:00
[ [ "Schul", "Raanan", "" ] ]
0706.2518
James Rabeau
J. R. Rabeau, A. Stacey, A. Rabeau, F. Jelezko, I. Mirza, J. Wrachtrup, S. Prawer
Single nitrogen vacancy centers in chemical vapor deposited diamond nanocrystals
16 pages, 4 figures, In Print Nano Letters (2007)
null
10.1021/nl0719271
null
cond-mat.mtrl-sci quant-ph
null
Nanodiamond crystals containing single color centers have been grown by chemical vapor deposition (CVD). The fluorescence from individual crystallites was directly correlated with crystallite size using a combined atomic force and scanning confocal fluorescence microscope. Under the conditions employed, the optimal size for single optically active nitrogen-vacancy (NV) center incorporation was measured to be 60 to 70 nm. The findings highlight a strong dependence of NV incorporation on crystal size, particularly with crystals less than 50 nm in size.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 00:48:41 GMT" }, { "version": "v2", "created": "Tue, 25 Sep 2007 04:49:05 GMT" } ]
2015-05-13T00:00:00
[ [ "Rabeau", "J. R.", "" ], [ "Stacey", "A.", "" ], [ "Rabeau", "A.", "" ], [ "Jelezko", "F.", "" ], [ "Mirza", "I.", "" ], [ "Wrachtrup", "J.", "" ], [ "Prawer", "S.", "" ] ]
0706.2519
Edmund Douglass
E. M. Douglass, Elizabeth L. Blanton, T. E. Clarke, Craig L. Sarazin, Michael Wise
Chandra Observation of the Cluster Environment of a WAT Radio Source in Abell 1446
40 AASTeX pages including 15 postscript figures; accepted for publication in ApJ
null
10.1086/523886
null
astro-ph
null
Wide-angle tail (WAT) radio sources are often found in the centers of galaxy clusters where intracluster medium (ICM) ram pressure may bend the lobes into their characteristic C-shape. We examine the low redshift (z=0.1035) cluster Abell 1446, host to the WAT radio source 1159+583. The cluster exhibits possible evidence for a small-scale cluster-subcluster merger as a cause of the WAT radio source morphology. This evidence includes the presence of temperature and pressure substructure along the line that bisects the WAT as well as a possible wake of stripped interstellar material or a disrupted cool core to the southeast of the host galaxy. A filament to the north may represent cool, infalling gas that's contributing to the WAT bending while spectroscopically determined redshifts of member galaxies may indicate some component of a merger occurring along the line-of-sight. The WAT model of high flow velocity and low lobe density is examined as another scenario for the bending of 1159+583. It has been argued that such a model would allow the ram pressure due to the galaxy's slow motion through the ICM to shape the WAT source. A temperature profile shows that the cluster is isothermal (kT= 4.0 keV) in a series of annuli reaching a radius of 400 kpc. There is no evidence of an ongoing cooling flow. Temperature, abundance, pressure, density, and mass profiles, as well as two-dimensional maps of temperature and pressure are presented.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 02:55:10 GMT" }, { "version": "v2", "created": "Tue, 27 Nov 2007 20:34:08 GMT" } ]
2009-11-13T00:00:00
[ [ "Douglass", "E. M.", "" ], [ "Blanton", "Elizabeth L.", "" ], [ "Clarke", "T. E.", "" ], [ "Sarazin", "Craig L.", "" ], [ "Wise", "Michael", "" ] ]
0706.2520
Viktoria Rojkova
Viktoria Rojkova, Mehmed Kantardzic
Analysis of Inter-Domain Traffic Correlations: Random Matrix Theory Approach
submitted to Internet Measurement Conference 2007
null
null
null
cs.NI
null
The traffic behavior of University of Louisville network with the interconnected backbone routers and the number of Virtual Local Area Network (VLAN) subnets is investigated using the Random Matrix Theory (RMT) approach. We employ the system of equal interval time series of traffic counts at all router to router and router to subnet connections as a representation of the inter-VLAN traffic. The cross-correlation matrix C of the traffic rate changes between different traffic time series is calculated and tested against null-hypothesis of random interactions. The majority of the eigenvalues \lambda_{i} of matrix C fall within the bounds predicted by the RMT for the eigenvalues of random correlation matrices. The distribution of eigenvalues and eigenvectors outside of the RMT bounds displays prominent and systematic deviations from the RMT predictions. Moreover, these deviations are stable in time. The method we use provides a unique possibility to accomplish three concurrent tasks of traffic analysis. The method verifies the uncongested state of the network, by establishing the profile of random interactions. It recognizes the system-specific large-scale interactions, by establishing the profile of stable in time non-random interactions. Finally, by looking into the eigenstatistics we are able to detect and allocate anomalies of network traffic interactions.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 01:31:54 GMT" } ]
2007-06-19T00:00:00
[ [ "Rojkova", "Viktoria", "" ], [ "Kantardzic", "Mehmed", "" ] ]
0706.2521
Aiguo Xu Dr.
Aiguo Xu, X. F. Pan, Guangcai Zhang, Jianshi Zhu
Material-Point Simulation to Cavity Collapse Under Shock
Figs.1,2,3,5,6,7 in JPG format, Accepted for publication in Journal of Physics: Condensed Matter
J. Phys.: Condens. Matter 19 (2007) 326212.
null
null
cond-mat.mtrl-sci cond-mat.soft
null
The collapse of cavities under shock is a key problem in various fields ranging from erosion of material, ignition of explosive, to sonoluminescence, etc. We study such processes using the material-point-method developed recently in the field of solid physics. The main points of the research include the relations between symmetry of collapsing and the strength of shock, other coexisting interfaces, as well as hydrodynamic and thermal-dynamic behaviors ignored by the pure fluid models. In the case with strong shock, we study the procedure of jet creation in the cavity; in the case with weak shock, we found that the cavity can not be collapsed completely by the shock and the cavity may collapse in a nearly isotropic way. The history of collapsing significantly influences the distribution of "hot spots" in the shocked material. The change in symmetry of collapsing is investigated. Since we use the Mie-Gr% \"{u}neisen equation of state and the effects of strain rate are not taken into account, the behavior is the same if one magnifies the spatial and temporal scales in the same way.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 01:54:52 GMT" } ]
2007-07-18T00:00:00
[ [ "Xu", "Aiguo", "" ], [ "Pan", "X. F.", "" ], [ "Zhang", "Guangcai", "" ], [ "Zhu", "Jianshi", "" ] ]
0706.2522
Howard M. Wiseman
H. M. Wiseman
Grounding Bohmian Mechanics in Weak Values and Bayesianism
11 pages
New J. Phys. 9 165 (2007)
10.1088/1367-2630/9/6/165
null
quant-ph
null
Bohmian mechanics (BM) is a popular interpretation of quantum mechanics in which particles have real positions. The velocity of a point x in configuration space is defined as the standard probability current j(x) divided by the probability density P(x). However, this ``standard'' j is in fact only one of infinitely many that transform correctly and satisfy \dot P + \del . j=0. In this article I show that there is a unique j that can be determined experimentally as a weak value using techniques that would make sense to a classical physicist. Moreover, this operationally defined j equals the standard j, so, assuming \dot x = j/P, the possible Bohmian paths can also be determined experimentally from a large enough ensemble. Furthermore, this approach to deriving BM singles out x as the hidden variable, because (for example) the operationally defined momentum current is in general incompatible with the evolution of the momentum distribution. Finally I discuss how, in this setting, the usual quantum probabilities can be derived from a Bayesian standpoint, via the principle of indifference.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 02:10:04 GMT" } ]
2007-06-19T00:00:00
[ [ "Wiseman", "H. M.", "" ] ]
0706.2523
Hugo F. Arellano
H. F. Arellano and W. G. Love
An in-medium full-folding model approach to quasielastic (p,n) charge-exchange reactions
20 pages plus 10 figures. Accepted for publication in Phys. Rev. C
Phys.Rev.C76:014616,2007
10.1103/PhysRevC.76.014616
null
nucl-th
null
A microscopic description of the quasielastic (p,n) charge-exchange reaction (here, charge-exchange scattering between analogue states) is presented and discussed. Emphasis is focused on the spin-isospin structure of the projectile-target coupling. The model is a coupled-channel extension of the full-folding optical model approach (OMP) developed for nucleon elastic scattering, where emphasis is placed on retaining the genuine off-shell behavior of realistic effective interactions in the nuclear medium. The resulting non-local optical potentials are applied to the calculation of (p,n) differential cross sections, with particular emphasis on small-angle Fermi ($\Delta S=0$) cross-sections to isobaric analog states. These parameter-free results provide a reasonable description of the $^{14}$C(p,n)-data at proton energies above $\sim$100 MeV, but deteriorate for heavier targets. These shortcomings are analyzed and possible ways to correct them are discussed.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 02:25:41 GMT" } ]
2008-11-26T00:00:00
[ [ "Arellano", "H. F.", "" ], [ "Love", "W. G.", "" ] ]
0706.2524
Nicola Magnani
N. Magnani, A. Hiess, R. Caciuffo, E. Colineau, F. Wastin, J. Rebizant, G. H. Lander
Magnetic Excitations in NpCoGa5
4 pages, 5 figures
Phys. Rev. B 76, 100404(R) (2007)
10.1103/PhysRevB.76.100404
null
cond-mat.str-el cond-mat.mtrl-sci
null
We report the results of inelastic neutron scattering experiments on NpCoGa$_{5}$, an isostructural analogue of the PuCoGa$_{5}$ superconductor. Two energy scales characterize the magnetic response in the antiferromagnetic phase. One is related to a non-dispersive excitation between two crystal field levels. The other at lower energies corresponds to dispersive fluctuations emanating from the magnetic zone center. The fluctuations persist in the paramagnetic phase also, although weaker in intensity. This supports the possibility that magnetic fluctuations are present in PuCoGa$_{5}$, where unconventional d-wave superconductivity is achieved in the absence of magnetic order.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 15:13:52 GMT" } ]
2007-09-15T00:00:00
[ [ "Magnani", "N.", "" ], [ "Hiess", "A.", "" ], [ "Caciuffo", "R.", "" ], [ "Colineau", "E.", "" ], [ "Wastin", "F.", "" ], [ "Rebizant", "J.", "" ], [ "Lander", "G. H.", "" ] ]
0706.2525
Siyoung Nam
Youngman Kim, Bum-Hoon Lee, Siyoung Nam, Chanyong Park, Sang-Jin Sin
Deconfinement phase transition in holographic QCD with matter
10 pages, 1 figure
Phys.Rev.D76:086003,2007
10.1103/PhysRevD.76.086003
null
hep-ph hep-th
null
In the framework of a holographic QCD approach we study an influence of matters on the deconfinement temperature, $T_c$. We first consider quark flavor number ($N_f$) dependence of $T_c$. We observe that $T_c$ decreases with $N_f$, which is consistent with a lattice QCD result. We also delve into how the quark number density $\rho_q$ affects the value of $T_c$. We find that $T_c$ drops with increasing $\rho_q$. In both cases, we confirm that the contributions from quarks are suppressed by $1/N_c$, as it should be, compared to the ones from a gravitational action (pure Yang-Mills).
[ { "version": "v1", "created": "Mon, 18 Jun 2007 04:48:20 GMT" } ]
2008-11-26T00:00:00
[ [ "Kim", "Youngman", "" ], [ "Lee", "Bum-Hoon", "" ], [ "Nam", "Siyoung", "" ], [ "Park", "Chanyong", "" ], [ "Sin", "Sang-Jin", "" ] ]
0706.2526
Kouichi Hagino
K. Hagino and Y. Watanabe
Potential inversion with subbarrier fusion data revisited
5 pages, 3 eps figures
Phys.Rev.C76:021601,2007
10.1103/PhysRevC.76.021601
null
nucl-th
null
We invert experimental data for heavy-ion fusion reactions at energies well below the Coulomb barrier in order to directly determine the internucleus potential between the colliding nuclei. In contrast to the previous applications of the inversion formula, we explicitly take into account the effect of channel couplings on fusion reactions, by assuming that fusion cross sections at deep subbarrier energies are governed by the lowest barrier in the barrier distribution. We apply this procedure to the $^{16}$O +$^{144}$Sm and $^{16}$O +$^{208}$Pb reactions, and find that the inverted internucleus potential are much thicker than phenomenological potentials. A relation to the steep fall-off phenomenon of fusion cross sections recently found at deep subbarrier energies is also discussed.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 03:46:54 GMT" } ]
2008-11-26T00:00:00
[ [ "Hagino", "K.", "" ], [ "Watanabe", "Y.", "" ] ]
0706.2527
Zhao-Ming Gan
Yi Xie, Chang-Yin Huang and Wei-Hua Lei
Effects of Magnetic Fields on Neutrino-dominated Accretion Model for Gamma-ray Bursts
10 pages, 4 figures, accepted by ChJAA
null
10.1088/1009-9271/7/5/09
null
astro-ph
null
Many models of gamma-ray bursts suggest a common central engine: a black hole of several solar masses accreting matter from a disk at an accretion rate from 0.01 to 10 M_\sun / s. The inner region of the disk is cooled by neutrino emission and large amounts of its binding energy were liberated, which could trigger the fireball. We improve the neutrino-dominated accreting flows by considering the effects of the magnetic fields, and find that more than half of the liberating energy can be extracted directly by the large-scale magnetic fields on the disk. And it turns out that the temperature of the disk is a bit lower than the neutrino-dominated accreting flows without magnetic field. Therefore, The outflows are magneticallydominated rather than neutrino dominated. In our model, neutrino mechanism can fuel some GRBs (not the brightest ones), but cannot fuel X-ray flares. However, the magnetic processes (both BZ and electromagnetic luminosity from a disk) are viable mechanisms for most of GRBs and the following X-ray flares.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 04:01:50 GMT" } ]
2009-11-13T00:00:00
[ [ "Xie", "Yi", "" ], [ "Huang", "Chang-Yin", "" ], [ "Lei", "Wei-Hua", "" ] ]
0706.2528
Sudipta Dutta
Sudipta Dutta, S. Lakshmi and Swapan K. Pati
Electron-Electron Interactions on the Edge States of Graphene: A Many Body Configuration Interaction Study
5 pages, 4 figures
Phys. Rev. B 77, 073412 (2008)
10.1103/PhysRevB.77.073412
null
cond-mat.mtrl-sci cond-mat.str-el
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We have studied zigzag and armchair graphene nano ribbons (GNRs), described by the Hubbard Hamiltonian using quantum many body configuration interaction methods. Due to finite termination, we find that the bipartite nature of the graphene lattice gets destroyed at the edges making the ground state of the zigzag GNRs a high spin state, whereas the ground state of the armchair GNRs remains a singlet. Our calculations of charge and spin densities suggest that, although the electron density prefers to accumulate on the edges, instead of spin polarization, the up and down spins prefer to mix throughout the GNR lattice. While the many body charge gap results in insulating behavior for both kinds of GNRs, the conduction upon application of electric field is still possible through the edge channels because of their high electron density. Analysis of optical states suggest differences in quantum efficiency of luminescence for zigzag and armchair GNRs, which can be probed by simple experiments.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 05:07:19 GMT" }, { "version": "v2", "created": "Tue, 22 Jul 2008 16:19:35 GMT" } ]
2009-11-13T00:00:00
[ [ "Dutta", "Sudipta", "" ], [ "Lakshmi", "S.", "" ], [ "Pati", "Swapan K.", "" ] ]
0706.2529
Akihiro Shibata
A. Shibata, S. Kato, K.-I. Kondo, T. Murakami, T. Shinohara and S. Ito
Compact lattice formulation of Cho-Faddeev-Niemi decomposition: gluon mass generation and infrared Abelian dominance
14 pages 5 figures,[v2]explanations added and improved, a reference added
Phys.Lett.B653:101-108,2007
10.1016/j.physletb.2007.07.042
CHIBA-EP-165, KEK Preprint 2007-19
hep-lat
null
This paper complements a new lattice formulation of SU(2) Yang-Mills theory written in terms of new variables in a compact form proposed in the previous paper. The new variables used in the formulation were once called the Cho--Faddeev--Niemi or Cho--Faddeev--Niemi--Shabanov decomposition. Our formulation enables us to explain the infrared ``Abelian'' dominance, in addition to magnetic monopole dominance shown in the previous paper, in the gauge invariant way without relying on the specific gauge fixing called the maximal Abelian gauge used in the conventional investigations. In this paper, especially, we demonstrate by numerical simulations that gluon degrees of freedom other than the ``Abelian'' part acquire the mass to be decoupled in the low-energy region leading to the infrared Abelian dominance.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 05:15:15 GMT" }, { "version": "v2", "created": "Wed, 25 Jul 2007 04:06:14 GMT" } ]
2008-11-26T00:00:00
[ [ "Shibata", "A.", "" ], [ "Kato", "S.", "" ], [ "Kondo", "K. -I.", "" ], [ "Murakami", "T.", "" ], [ "Shinohara", "T.", "" ], [ "Ito", "S.", "" ] ]
0706.2530
N. E. Csima
N. E. Csima
Newton-Hodge Filtration for Self-Dual F-Crystals
13 pages
null
null
null
math.AG
null
In this paper we study F-crystals with self-dual structure over base schemes of characteristic p. We generalize Katz's Newton-Hodge Filtration Theorem to F-crystals with self-dual structure.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 05:32:17 GMT" } ]
2007-06-19T00:00:00
[ [ "Csima", "N. E.", "" ] ]
0706.2531
Yuji Kajiyama
Yuji Kajiyama
R-Parity Violation and Family Symmetry
11pages, 2 figures. Talk given at CTP symposium on Supersymmetry at LHC: Theoretical and Experimental Perspectives, The British University in Egypt, Cairo, Egypt, 11-14 March 2007
Int.J.Mod.Phys.A22:5909-5919,2007
10.1142/S0217751X07039110
null
hep-ph
null
In this talk, we investigate the implications of R-parity violating (RPV) operators in a model with family symmetry. Family symmetry can determine the form of RPV operators as well as the Yukawa matrices. We consider a concrete model with non-abelian discrete symmetry Q_6, which has only three RPV trilinear operators with no baryon number violating terms. We find that ratios of decay rates of the lepton flavor violating processes are fixed thanks to the family symmetry, predicting BR(tau to 3e)/BR(tau to 3mu) ~ 4 m_{mu}^2/m_{tau}^2.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 05:45:15 GMT" } ]
2010-11-03T00:00:00
[ [ "Kajiyama", "Yuji", "" ] ]
0706.2532
Probir Roy
Probir Roy (Tata Inst.)
Neutrino symmetries from high to low scales
8 pages, 2 figures. Talk given at the International Workshop on Theoretical and Experimental Physics, IIT (Roorkee), March 2007
AIPConf.Proc.939:286-293,2007
10.1063/1.2803817
null
hep-ph
null
Proposed symmetry relations, e.g., quark-lepton complementarity (QLC) or tribimaximal mixing (TBM), need to be imposed at a high scale $\wedge \sim 10^{12}$ GeV characterising the large masses of right-handed neutrinos required to implement the seesaw mechanism. RG evolution down to the laboratory scale $\lambda \sim 10^3$ GeV, generically prone to spoil these relations and their predicted neutrino mixing patterns, can be made to preserve them by appropriately constraining the Majorana phases $\alpha_{2,3}$. This is explicitly demonstrated in the MSSM for two versions of QLC and two versions of TBM. A preference for $\alpha_2 \simeq \pi$ (i.e. $m_1 \simeq - m_2$) emerges in each case. Discrimination among the four cases is shown to be possible by future measurements of $\theta_{13}$.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 06:00:19 GMT" } ]
2008-11-26T00:00:00
[ [ "Roy", "Probir", "", "Tata Inst." ] ]
0706.2533
Dr. Rukmani Mohanta
A.K.Giri, B.Mawlong, R. Mohanta
Weak phase information from the color suppressed B_d^0 -> D^{*0} K^{*0} modes
11 pages, revised extensively, version to appear in Phys. Rev. D
Phys.Rev.D76:093008,2007
10.1103/PhysRevD.76.093008
null
hep-ph
null
The decay channels $B_d^0 \to D^{*0} K^{*0}$ are investigated for extracting weak $CKM$ phase information. These channels are described by color-suppressed tree diagrams only and are free from penguin contributions. The branching ratios for these channels are found to be $\sim \cal O $ $(10^{-5} - 10^{-6})$ which can be measured at the currently running $B$ factories. The method presented here may be well-suited to determine the phase $\gamma$.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 06:17:44 GMT" }, { "version": "v2", "created": "Mon, 22 Oct 2007 03:49:08 GMT" } ]
2008-11-26T00:00:00
[ [ "Giri", "A. K.", "" ], [ "Mawlong", "B.", "" ], [ "Mohanta", "R.", "" ] ]
0706.2534
Yoshio Koide
Yoshio Koide
Charged Lepton Mass Formula -- Development and Prospect --
Latex, 11 pages, no figure, Talk at Internationa Workshop on Neutrino Masses and Mixing, at Shizuoka, Japan, December, 17-19, 2006
Int.J.Mod.Phys.E16:1417-1426,2007
10.1142/S0218301307006770
null
hep-ph
null
The recent devolopment on the charged lepton mass forumula m_e+m_{\mu}+m_{\tau}={2/3}(\sqrt{m_e}+\sqrt{m_\mu}+\sqrt{m_{\tau}})^2 is reviewed. An S_3 or A_4 model will be promising for the mass relation.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 06:20:31 GMT" } ]
2008-11-26T00:00:00
[ [ "Koide", "Yoshio", "" ] ]
0706.2535
Rostyslav Vlokh O
R. Vlokh, I.Vlokh, O. Moroz, Yu. Nastishin, K. Dudok, T. Dudok, N. Grinchishin, I. Nechiporenko, A. Hul
Optical Marking of Alcohol Induced Hemoglobin Modification
34 pages, 5 figures, 4 tables. submitted to the Journal of Biomedical Optics
null
null
null
physics.bio-ph physics.med-ph
null
It has been shown that conformational modifications of Hb induced by ethanol consumption can be visualized in optical spectra studying oxygenation kinetics of hemoglobin or mixing hemoglobin with Cibacron blue dye. Better dye affinity of blood proteins extracted from alcoholised rats with respect to those from non-alcoholised ones confirms that ethanol and its metabolites induce structural pathologies in blood protein molecules. The detected changes for the case of the posterity of intoxicated animals may be explained as a post-translation modification, as well as a disturbance of the structure and function of tissue cellular gene mechanism for the blood creation. It is established that alcohol intake during first four months leads to the decrease of fractional weight of oxyhemoglobin and to the increase of methemoglobin amount in blood. Further alcohol consumption is accompanied by recovering of the normal level of hemoglobin derivatives in blood. Normalization of the fractional weight of hemoglobin derivatives in blood after durable (longer than 5-6 months) ethanol intoxication is most probably due to the activation of the enzyme (acetaldehyde dehydrogenase) system, lowering the level of acetaldehydes in blood.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 06:55:45 GMT" } ]
2007-06-19T00:00:00
[ [ "Vlokh", "R.", "" ], [ "Vlokh", "I.", "" ], [ "Moroz", "O.", "" ], [ "Nastishin", "Yu.", "" ], [ "Dudok", "K.", "" ], [ "Dudok", "T.", "" ], [ "Grinchishin", "N.", "" ], [ "Nechiporenko", "I.", "" ], [ "Hul", "A.", "" ] ]
0706.2536
Wei-Min Zhang
Matisse W. Y. Tu and Wei-Min Zhang
Exact wave-packet decoherence dynamics in a discrete spectrum environment
12 pages, 2 figures
J. Phys. B: At. Mol. Opt. Phys. 41, 245501 (2008)
10.1088/0953-4075/41/24/245501
null
quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We find an exact analytical solution of the reduced density matrix from the Feynman-Vernon influence functional theory for a wave packet influenced by an environment containing a few discrete modes. We obtain two intrinsic energy scales relating to the time scales of the system and the environment. Different relationship between these two scales alters the overall form of the solution of the system. We also introduce a decoherence measure for a single wave packet which is defined as the ratio of Schr\"odinger uncertainty over the delocalization extension of the wave packet and characterizes the time-evolution behavior of the off-diagonal reduced density matrix element. We utilize the exact solution and the docherence measure to study the wave packet decoherence dynamics. We further demonstrate how the dynamical diffusion of the wave packet leads to non-Markovian decoherence in such a microscopic environment.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 06:56:56 GMT" }, { "version": "v2", "created": "Tue, 30 Sep 2008 05:36:21 GMT" } ]
2009-11-13T00:00:00
[ [ "Tu", "Matisse W. Y.", "" ], [ "Zhang", "Wei-Min", "" ] ]
0706.2537
Israfil Guseinov
I.I.Guseinov
One-Range Addition Theorems in Terms of -ETOs for STOs and Coulomb-Yukawa Like Correlated Interaction Potentials of Integer and Noninteger Indices
This paper has been published in Journal of Math.Chem
null
null
null
physics.chem-ph
null
In this study, the one-center expansion formulas in terms of complete orthonormal sets of -exponential type orbitals (-ETOs,) are established for the Slater type orbitals (STOs) and Coulomb-Yukawa like correlated interaction potentials (CIPs) of integer and noninteger indices. These relations are used in obtaining the unsymmetrical and symmetrical one-range addition theorems for STOs and Coulomb-Yukawa like CIPs. The final results are especially useful in the calculations of multicenter multielectron integrals of STOs and CIPs occurring when Hartree-Fock-Roothaan (HFR) and explicitly correlated method are employed.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 07:16:18 GMT" }, { "version": "v2", "created": "Sat, 9 Feb 2013 20:28:38 GMT" } ]
2013-02-12T00:00:00
[ [ "Guseinov", "I. I.", "" ] ]
0706.2538
Anna Galas ag
ZEUS Collaboration: S. Chekanov, et al
Bose-Einstein Correlations of Charged and Neutral Kaons in Deep Inelastic Scattering at HERA
24 pages, 5 figures, 1 table submitted to Physics Letters B
Phys.Lett.B652:1-12,2007
10.1016/j.physletb.2007.06.052
DESY-07-069
hep-ex
null
Bose-Einstein correlations of charged and neutral kaons have been measured in e+-p deep inelastic scattering with an integrated luminosity of 121 pb-1 using the ZEUS detector at HERA. The two-particle correlation function was studied as a function of the four-momentum difference of the kaon pairs, Q_12=sqrt{-(p_1-p_2)^2}, assuming a Gaussian shape for the particle source. The values of the radius of the production volume, r, and of the correlation strength, lambda, were obtained for both neutral and charged kaons. The radii for charged and neutral kaons are similar and are consistent with those obtained at LEP.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 07:16:18 GMT" } ]
2012-08-03T00:00:00
[ [ "ZEUS Collaboration", "", "" ], [ "Chekanov", "S.", "" ] ]
0706.2539
Marko Znidaric
Marko Znidaric, Tomaz Prosen and Peter Prelovsek
Many body localization in Heisenberg XXZ magnet in a random field
6 pages, 5 PS figures; v2: few minor changes, one additional figure
Phys. Rev. B 77, 064426 (2008)
10.1103/PhysRevB.77.064426
null
quant-ph cond-mat.str-el
null
We numerically investigate Heisenberg XXZ spin-1/2 chain in a spatially random static magnetic field. We find that tDMRG simulations of time evolution can be performed efficiently, namely the dimension of matrices needed to efficiently represent the time-evolution increases linearly with time and entanglement entropies for typical chain bipartitions increase logarithmically. As a result, we show that for large enough random fields infinite temperature spin-spin correlation function displays exponential localization in space indicating insulating behavior of the model.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 07:18:13 GMT" }, { "version": "v2", "created": "Wed, 19 Mar 2008 12:32:09 GMT" } ]
2008-03-19T00:00:00
[ [ "Znidaric", "Marko", "" ], [ "Prosen", "Tomaz", "" ], [ "Prelovsek", "Peter", "" ] ]
0706.2540
Edmond Iancu
A. Dumitru, E. Iancu, L. Portugal, G. Soyez, D.N. Triantafyllopoulos
Pomeron loop and running coupling effects in high energy QCD evolution
23 pages, 8 figures
JHEP0708:062,2007
10.1088/1126-6708/2007/08/062
null
hep-ph
null
Within the framework of a (1+1)-dimensional model which mimics evolution and scattering in QCD at high energy, we study the influence of the running of the coupling on the high-energy dynamics with Pomeron loops. We find that the particle number fluctuations are strongly suppressed by the running of the coupling, by at least one order of magnitude as compared to the case of a fixed coupling, for all the rapidities that we have investigated, up to Y=200. This reflects the slowing down of the evolution by running coupling effects, in particular, the large rapidity evolution which is required for the formation of the saturation front via diffusion. We conclude that, for all energies of interest, processes like deep inelastic scattering or forward particle production can be reliably studied within the framework of a mean-field approximation (like the Balitsky-Kovchegov equation) which includes running coupling effects.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 07:19:24 GMT" } ]
2008-11-26T00:00:00
[ [ "Dumitru", "A.", "" ], [ "Iancu", "E.", "" ], [ "Portugal", "L.", "" ], [ "Soyez", "G.", "" ], [ "Triantafyllopoulos", "D. N.", "" ] ]
0706.2541
Pablo Laguna
Frank Herrmann, Ian Hinder, Deirdre M. Shoemaker, Pablo Laguna and Richard A. Matzner
Binary Black Holes: Spin Dynamics and Gravitational Recoil
15 pages, 10 figures, replaced with version accepted for publication in PRD
Phys.Rev.D76:084032,2007
10.1103/PhysRevD.76.084032
null
gr-qc astro-ph
null
We present a study of spinning black hole binaries focusing on the spin dynamics of the individual black holes as well as on the gravitational recoil acquired by the black hole produced by the merger. We consider two series of initial spin orientations away from the binary orbital plane. In one of the series, the spins are anti-aligned; for the second series, one of the spins points away from the binary along the line separating the black holes. We find a remarkable agreement between the spin dynamics predicted at 2nd post-Newtonian order and those from numerical relativity. For each configuration, we compute the kick of the final black hole. We use the kick estimates from the series with anti-aligned spins to fit the parameters in the \KKF{,} and verify that the recoil along the direction of the orbital angular momentum is $\propto \sin\theta$ and on the orbital plane $\propto \cos\theta$, with $\theta$ the angle between the spin directions and the orbital angular momentum. We also find that the black hole spins can be well estimated by evaluating the isolated horizon spin on spheres of constant coordinate radius.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 17:47:38 GMT" }, { "version": "v2", "created": "Mon, 17 Sep 2007 17:27:37 GMT" } ]
2008-11-26T00:00:00
[ [ "Herrmann", "Frank", "" ], [ "Hinder", "Ian", "" ], [ "Shoemaker", "Deirdre M.", "" ], [ "Laguna", "Pablo", "" ], [ "Matzner", "Richard A.", "" ] ]
0706.2542
Sang-Koog Kim
Jun-Young Lee, Ki-Suk Lee, Sangkook Choi, Konstantin Y. Guslienko, and Sang-Koog Kim
Understanding of complex periodic transformations of moving domain walls in magnetic nanostripes
25 pages, 4 figures
Phys. Rev. B 76, 184408 (2007)
10.1103/PhysRevB.76.184408
null
cond-mat.other cond-mat.soft
null
The magnetic field (or electric current) driven domain-wall motion in magnetic nanostripes is of considerable interest because it is essential to the performance of information storage and logic devices. One of the currently key problems is to unveil the complex behaviors of oscillatory domain-wall motions under applied magnetic fields stronger than the so-called Walker field, beyond which the velocity of domain walls markedly drops. Here, we provide not only considerably better understandings but also new details of the complex domain-wall motions. In a certain range just above the Walker field, the motions are not chaotic but rather periodic with different unique periodicities of dynamic transformations of a moving domain wall between the different types of its internal structure. Three unique periodicities found, which consist of different types of domain wall that are transformed from type one to another. The transformation periods vary with the field strength and the nanostripe width. This novel phenomenon can be described by the dynamic motion of a limited number of magnetic topological solitons such as vortex and antivortex in nanostripes.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 07:53:54 GMT" } ]
2007-11-20T00:00:00
[ [ "Lee", "Jun-Young", "" ], [ "Lee", "Ki-Suk", "" ], [ "Choi", "Sangkook", "" ], [ "Guslienko", "Konstantin Y.", "" ], [ "Kim", "Sang-Koog", "" ] ]
0706.2543
Tolga Birkandan
T. Birkandan, M. Hortacsu
Dirac Equation in the Background of the Nutku Helicoid Metric
16 pages, 1 figure, TeX file using boxedeps. Replaced by the revised version
J.Math.Phys.48:092301,2007
10.1063/1.2785124
null
gr-qc math-ph math.MP
null
We study the solutions of the Dirac equation in the background of the Nutku helicoid metric. This metric has curvature singularities, which necessitates imposing a boundary to exclude this point. We use the Atiyah-Patodi-Singer non local spectral boundary conditions for both the four and the five dimensional manifolds.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 07:56:46 GMT" }, { "version": "v2", "created": "Mon, 3 Sep 2007 06:50:04 GMT" } ]
2008-11-26T00:00:00
[ [ "Birkandan", "T.", "" ], [ "Hortacsu", "M.", "" ] ]
0706.2544
Pierre-Louis Curien
Pierre-Louis Curien (PPS), Hugo Herbelin (INRIA Futurs)
Abstract machines for dialogue games
null
null
null
null
cs.LO
null
The notion of abstract Boehm tree has arisen as an operationally-oriented distillation of works on game semantics, and has been investigated in two papers. This paper revisits the notion, providing more syntactic support and more examples (like call-by-value evaluation) illustrating the generality of the underlying computing device. Precise correspondences between various formulations of the evaluation mechanism of abstract Boehm trees are established.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 08:01:12 GMT" } ]
2007-06-19T00:00:00
[ [ "Curien", "Pierre-Louis", "", "PPS" ], [ "Herbelin", "Hugo", "", "INRIA Futurs" ] ]
0706.2545
Yuji Koike
Yuji Koike (Niigata University), Kazuhiro Tanaka (Juntendo University)
Factorization and Gauge Invariance of Twist-3 Cross Section for Single Spin Asymmetry
4 pages, 2 figures. Talk presented at DIS2007, April 16-20, 2007, Munich, Germany
null
null
null
hep-ph
null
We prove factorization and gauge invariance of the twist-3 single-spin-dependent cross section in the leading order perturbative QCD, which was missing in the previous literature. We emphasize that the consistency relation from the Ward identities for color gauge invariance is crucial to guarantee the cancelation among the various gauge-noninvariant contributions in the cross section. This relation also proves the absence of the "derivative" terms in the cross section corresponding to the hard-pole and soft-fermion-pole contributions. Applying the formalism to SIDIS, $ep^\uparrow\to e\pi X$, we have derived the complete cross section associated with the twist-3 distribution for the transversely polarized nucleon.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 08:02:12 GMT" } ]
2007-06-19T00:00:00
[ [ "Koike", "Yuji", "", "Niigata University" ], [ "Tanaka", "Kazuhiro", "", "Juntendo University" ] ]
0706.2546
Giuseppe Mussardo
Giuseppe Mussardo
Kink Confinement and Supersymmetry
29 pages, 12 figures
JHEP 0708:003,2007
10.1088/1126-6708/2007/08/003
null
hep-th cond-mat.stat-mech hep-lat
null
We analyze non-integrable deformations of two-dimensional N=1 supersymmetric quantum field theories with kink excitations. As example, we consider the multi-frequency Super Sine Gordon model. At weak coupling, this model is robust with respect to kink confinement phenomena, in contrast to the purely bosonic case. If we vary the coupling, the model presents a sequence of phase transitions, where pairs of kinks disappear from the spectrum. The phase transitions fall into two classes: the first presents the critical behaviors of the Tricritical Ising model, the second instead those of the gaussian model. In the first case, close to the critical point, the model has metastable vacua, with a spontaneously supersymmetry breaking. When the life-time of the metastable vacua is sufficiently long, the role of goldstino is given by the massless Majorana fermion of the Ising model. On the contrary, supersymmetry remains exact in the phase transition of the second type.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 08:05:57 GMT" } ]
2009-11-18T00:00:00
[ [ "Mussardo", "Giuseppe", "" ] ]
0706.2547
Angela Malizia
A. Malizia, R. Landi, L. Bassani, A.J. Bird, M. Molina, A. De Rosa, M. Fiocchi, N. Gehrels, J.Kennea, M. Perri
Swift-XRT observation of 34 new INTEGRAL/IBIS AGNs: discovery of Compton thick and other peculiar sources
15 pages, 5 figures, ApJ accepted
null
10.1086/520874
null
astro-ph
null
For a significant number of the sources detected at high energies (>10 keV) by the INTEGRAL/IBIS and Swift/BAT instruments there is either a lack information about them in the 2-10 keV range or they are totally unidentified. Herein, we report on a sample of 34 IBIS AGN or AGN candidate objects for which there is X-ray data in the Swift/XRT archive. Thanks to these X-ray follow up observations, the identification of the gamma ray emitters has been possible and the spectral shape in terms of photon index and absorption has been evaluated for the first time for the majority of our sample sources. The sample, enlarged to include 4 more AGN already discussed in the literature, has been used to provide photon index and column density distribution. We obtain a mean value of 1.88 with a dispersion of 0.12, i.e. typical of an AGN sample. Sixteen objects (47%) have column densities in excess of 10^{22} cm^{-2} and, as expected, a large fraction of the absorbed sources are within the Sey 2 sample. We have provided a new diagnostic tool (NH versus F(2-10)keV/F(20-100)keV softness ratio) to isolate peculiar objects; we find at least one absorbed Sey 1 galaxy, 3 Compton thick AGN candidates; and one secure example of a "true" type 2 AGN. Within the sample of 10 still unidentified objects, 3 are almost certainly AGN of type 2; 3 to 4 have spectral slopes typical of AGN; and two are located high on the galactic plane and are strong enough radio emitters so that can be considered good AGN candidates.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 15:13:33 GMT" } ]
2009-11-13T00:00:00
[ [ "Malizia", "A.", "" ], [ "Landi", "R.", "" ], [ "Bassani", "L.", "" ], [ "Bird", "A. J.", "" ], [ "Molina", "M.", "" ], [ "De Rosa", "A.", "" ], [ "Fiocchi", "M.", "" ], [ "Gehrels", "N.", "" ], [ "Kennea", "J.", "" ], [ "Perri", "M.", "" ] ]
0706.2548
Dominic Schnitzeler
D.H.F.M. Schnitzeler, P. Katgert and A.G. de Bruyn
WSRT Faraday tomography of the Galactic ISM at \lambda \sim 0.86 m
5 pages, 5 figures. Accepted for publication as a Letter to the Editor in A&A
null
10.1051/0004-6361:20077635
null
astro-ph
null
We investigate the distribution and properties of Faraday rotating and synchrotron emitting regions in the Galactic ISM in the direction of the Galactic anti-centre. We apply Faraday tomography to a radio polarization dataset that we obtained with the WSRT. We developed a new method to calculate a linear fit to periodic data, which we use to determine rotation measures from our polarization angle data. From simulations of a Faraday screen + noise we could determine how compatible the data are with Faraday screens. An unexpectedly large fraction of 14% of the lines-of-sight in our dataset show an unresolved main component in the Faraday depth spectrum. For lines-of-sight with a single unresolved component we demonstrate that a Faraday screen in front of a synchrotron emitting region that contains a turbulent magnetic field component can explain the data.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 20:03:09 GMT" } ]
2015-05-13T00:00:00
[ [ "Schnitzeler", "D. H. F. M.", "" ], [ "Katgert", "P.", "" ], [ "de Bruyn", "A. G.", "" ] ]
0706.2549
Massimo Pica Ciamarra
Massimo Pica Ciamarra, Gennaro Miele, Leopoldo Milano, Mario Nicodemi, Giancarlo Raiconi
A statistical mechanics approach to reverse engineering: sparsity and biological priors on gene regulatory networks
null
null
null
null
q-bio.MN q-bio.QM
null
The important task of determining the connectivity of gene networks, and at a more detailed level even the kind of interaction existing between genes, can nowadays be tackled by microarraylike technologies. Yet, there is still a large amount of unknowns with respect to the amount of data provided by a single microarray experiment, and therefore reliable gene network retrieval procedures must integrate all of the available biological knowledge, even if coming from different sources and of different nature. In this paper we present a reverse engineering algorithm able to reveal the underlying gene network by using time-series dataset on gene expressions considering the system response to different perturbations. The approach is able to determine the sparsity of the gene network, and to take into account possible {\it a priori} biological knowledge on it. The validity of the reverse engineering approach is highlighted through the deduction of the topology of several {\it simulated} gene networks, where we also discuss how the performance of the algorithm improves enlarging the amount of data or if any a priori knowledge is considered. We also apply the algorithm to experimental data on a nine gene network in {\it Escherichia coli
[ { "version": "v1", "created": "Mon, 18 Jun 2007 08:25:04 GMT" } ]
2007-06-19T00:00:00
[ [ "Ciamarra", "Massimo Pica", "" ], [ "Miele", "Gennaro", "" ], [ "Milano", "Leopoldo", "" ], [ "Nicodemi", "Mario", "" ], [ "Raiconi", "Giancarlo", "" ] ]
0706.2550
G. Massimo Palma
Ugo Messina and G.Massimo Palma
Entanglement swapping in a Franson interferometer setup
Published on the special issue of JMO in honour of the 60th birthday of Sir Peter Knight, FRS. Submitted to JMO on 10 February 2007. While the present manuscript was processed an independent experimental implementation of the same scheme discussed in our manuscript has been made bythe Geneva GAP as described in arXiv:0704.0758v1
Journal of Modern Optics 54, 2297-2306, (2007)
10.1080/09500340701514339
null
quant-ph
null
We propose a simple scheme to swap the non local correlations, characteristic of a Franson interferometric setup, between pairs of frequency entangled photons emitted by distinct non linear crystals in a parametric down conversion process. Our scheme consists of two distinct sources of frequency entangled photons. One photon of each pair is sent to a separate Mach - Zender interferometer while the other photons of the pairs are mixed by a beam splitter and then detected in a Ou - Mandel interferometer. For suitably postselected joint measuremetns, the photons sent at the Mach -Zender show a coincidence photocount statistics which depends non locally on the settings of the two interferometers.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 08:36:05 GMT" }, { "version": "v2", "created": "Wed, 3 Oct 2007 09:34:44 GMT" } ]
2017-08-23T00:00:00
[ [ "Messina", "Ugo", "" ], [ "Palma", "G. Massimo", "" ] ]
0706.2551
Jie Wang
Jie Wang, Gabriella De Lucia, Manfred G. Kitzbichler, Simon D. M. White (MPA)
The Dependence of Galaxy Formation on Cosmological Parameters: Can we distinguish the WMAP1 and WMAP3 Parameter Sets?
18 pages,17 figures, version accepted by MNRAS, references and subsection on PVD added
null
10.1111/j.1365-2966.2007.12797.x
null
astro-ph
null
We combine N-body simulations of structure growth with physical modelling of galaxy evolution to investigate whether the shift in cosmological parameters between the 1-year and 3-year results from the Wilkinson Microwave Anisotropy Probe affects predictions for the galaxy population. Structure formation is significantly delayed in the WMAP3 cosmology, because the initial matter fluctuation amplitude is lower on the relevant scales. The decrease in dark matter clustering strength is, however, almost entirely offset by an increase in halo bias, so predictions for galaxy clustering are barely altered. In both cosmologies several combinations of physical parameters can reproduce observed, low-redshift galaxy properties; the star formation, supernova feedback and AGN feedback efficiencies can be played off against each other to give similar results. Models which fit observed luminosity functions predict projected 2-point correlation functions which scatter by about 10-20 per cent on large scale and by larger factors on small scale, depending both on cosmology and on details of galaxy formation. Measurements of the pairwise velocity distribution prefer the WMAP1 cosmology, but careful treatment of the systematics is needed. Given current modelling uncertainties, it is not easy to distinguish the WMAP1 and WMAP3 cosmologies on the basis of low-redshift galaxy properties. Model predictions diverge more dramatically at high redshift. Better observational data at z>2 will better constrain galaxy formation and perhaps also cosmological parameters.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 09:06:22 GMT" }, { "version": "v2", "created": "Mon, 3 Dec 2007 16:58:47 GMT" } ]
2009-11-13T00:00:00
[ [ "Wang", "Jie", "", "MPA" ], [ "De Lucia", "Gabriella", "", "MPA" ], [ "Kitzbichler", "Manfred G.", "", "MPA" ], [ "White", "Simon D. M.", "", "MPA" ] ]
0706.2552
Sylvie Paycha
Sylvie Paycha
The noncommutative residue and canonical trace in the light of Stokes' and continuity properties
null
null
null
null
math.OA math.AP
null
We show that the noncommutative residue density, resp. the cut-off regularised integral are the only closed linear, resp. continuous closed linear forms on certain classes of symbols. This leads to alternative proofs of the uniqueness of the noncommutative residue, resp. the canonical trace as linear, resp. continuous linear forms on certain classes of classical pseudodifferential operators which vanish on brackets. The uniqueness of the canonical trace actually holds on classes of classical pseudodifferential with vanishing residue density which include non integer order operators in all dimensions and odd-class (resp. even-class) operators in odd (resp. even) dimensions. The description of the canonical trace for non integer order operators as an integrated global density on the manifold is extended to odd-class (resp. even-class) operators in odd (resp. even) dimensions on the grounds of defect formulae for regularised traces of classical pseudodifferential operators.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 08:46:24 GMT" } ]
2007-06-19T00:00:00
[ [ "Paycha", "Sylvie", "" ] ]
0706.2553
Cl\'audio Nassif Cruz
Claudio Nassif, A. C. Amaro de Faria Jr. and P. R. Silva
Asymptotic freedom and quarks confinement treated through Thompson's approach
16 pages, no figures and 34 references
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work, we first use Thompson's renormalization group method to treat QCD-vacuum behavior close to the regime of asymptotic freedom. QCD-vacuum behaves effectively like a "paramagnetic system" of a classical theory in the sense that virtual color charges (gluons) emerge in it as spin effect of a paramagnetic material when a magnetic field aligns their microscopic magnetic dipoles. Making a classical analogy with the paramagnetism of Landau's theory,we are able to introduce a kind of Landau effective action without temperature and phase transition for simply representing QCD-vacuum behavior at higher energies as magnetization of a paramagnetic material in the presence of a magnetic field H. This reasoning allows us to use Thompson's heuristic approach in order to extract an "effective susceptibility" ($\chi>0$) of QCD-vacuum. It depends on logarithmic of energy scale u to investigate hadronic matter. Consequently,we are able to get an "effective magnetic permeability" ($\mu>1$) of such a "paramagnetic vacuum". As QCD-vacuum must obey Lorentz invariance,the attainment of $\mu>1$ must simply require that the "effective electrical permissivity" is $\epsilon<1$,in such a way that $\mu\epsilon=1$ (c^2=1).This leads to the antiscreening effect, where the asymptotic freedom takes place. On the other hand, quarks cofinement, a subject which is not treatable by perturbative calculations, is worked by the present approach. We apply the method to study this subject in order to obtain the string constant, which is in agreement with the experiments.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 08:50:15 GMT" }, { "version": "v2", "created": "Tue, 10 Jul 2007 09:08:33 GMT" }, { "version": "v3", "created": "Thu, 2 Aug 2007 16:56:28 GMT" }, { "version": "v4", "created": "Thu, 7 Apr 2016 01:17:17 GMT" } ]
2016-04-08T00:00:00
[ [ "Nassif", "Claudio", "" ], [ "Faria", "A. C. Amaro de", "Jr." ], [ "Silva", "P. R.", "" ] ]
0706.2554
Sylvie Paycha
Sylvie Paycha
Chern-Weil calculus extended to a class of infinite dimensional manifolds
null
null
null
null
math.DG math.OA
null
We discuss possible extensions of the classical Chern-Weil formalism to an infinite dimensional setup. This is based on joint work with Steven Rosenberg, joint work with Simon Scott and joint work with Jouko Mickelsson.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 09:03:28 GMT" } ]
2007-06-19T00:00:00
[ [ "Paycha", "Sylvie", "" ] ]
0706.2555
Simon Verley
S. Verley, S. Leon, L. Verdes-Montenegro, F. Combes, J. Sabater, J. Sulentic, G. Bergond, D. Espada, E. Garcia, U. Lisenfeld, S. C. Odewahn
The AMIGA sample of isolated galaxies. V. Quantification of the isolation
10 pages, 12 figures, proposed for acceptance A&A
null
10.1051/0004-6361:20077481
null
astro-ph
null
The AMIGA project aims to build a well defined and statistically significant reference sample of isolated galaxies in order to estimate the environmental effects on the formation and evolution of galaxies. The goal of this paper is to provide a measure of the environment of the isolated galaxies in the AMIGA sample, quantifying the influence of the candidate neighbours identified in our previous work and their potential effects on the evolution of the primary galaxies. Here we provide a quantification of the isolation degree of the galaxies in this sample. Our starting sample is the Catalogue of Isolated Galaxies (CIG). We used two parameters to estimate the influence exerted by the neighbour galaxies on the CIG galaxy: the local number density of neighbour galaxies and the tidal strength affecting the CIG galaxy. We show that both parameters together provide a comprehensive picture of the environment. For comparison, those parameters have also been derived for galaxies in denser environments such as triplets, groups and clusters. The CIG galaxies show a continuous spectrum of isolation, as quantified by the two parameters, from very isolated to interacting. The fraction of CIG galaxies whose properties are expected to be influenced by the environment is however low (159 out of 950 galaxies). The isolated parameters derived for the comparsion samples gave higher values than for the CIG and we found clear differences for the average values of the 4 samples considered, proving the sensitivity of these parameters. The environment of the galaxies in the CIG has been characterised, using two complementary parameters quantifying the isolation degree, the local number density of the neighbour galaxies and the tidal forces affecting the isolated galaxies. (Abridged)
[ { "version": "v1", "created": "Mon, 18 Jun 2007 09:05:05 GMT" } ]
2009-11-13T00:00:00
[ [ "Verley", "S.", "" ], [ "Leon", "S.", "" ], [ "Verdes-Montenegro", "L.", "" ], [ "Combes", "F.", "" ], [ "Sabater", "J.", "" ], [ "Sulentic", "J.", "" ], [ "Bergond", "G.", "" ], [ "Espada", "D.", "" ], [ "Garcia", "E.", "" ], [ "Lisenfeld", "U.", "" ], [ "Odewahn", "S. C.", "" ] ]
0706.2556
Peter Hogan
C. Barrabes and P. A. Hogan
Inhomogeneous High Frequency Expansion-Free Gravitational Waves
18 pages, Latex file, accepted for publication in Physical Review D
Phys.Rev.D75:124012,2007
10.1103/PhysRevD.75.124012
null
gr-qc
null
We describe a natural inhomogeneous generalization of high frequency plane gravitational waves. The waves are high frequency waves of the Kundt type whose null propagation direction in space-time has vanishing expansion, twist and shear but is not covariantly constant. The introduction of a cosmological constant is discussed in some detail and a comparison is made with high frequency gravity waves having wave fronts homeomorphic to 2-spheres.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 09:29:34 GMT" } ]
2008-11-26T00:00:00
[ [ "Barrabes", "C.", "" ], [ "Hogan", "P. A.", "" ] ]
0706.2557
Silvia Miglioranzi
S. Miglioranzi
Heavy Flavor Production at HERA
4 pages, 8 figures, contribution to the proceedings for Moriond 2007 QCD session
null
null
null
hep-ex
null
Studies of charm and beauty production in ep collisions with a center-of-mass energy of 318 GeV are reported from the two HERA collaborations, H1 and ZEUS. The analyses make use of both the HERA-I data sample recorded between 1996 and 2000 and a sample from HERA-II, which started in 2003. The cross sections measured by both H1 and ZEUS experiments are compared with next-to-leading order QCD calculations. The measurement of the charm and beauty contributions to the proton structure function is also presented. The comparison to next-to-next-to-leading order (NNLO) calculations shows agreement within the errors.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 09:29:44 GMT" } ]
2007-06-19T00:00:00
[ [ "Miglioranzi", "S.", "" ] ]
0706.2558
Yago Ascasibar
Y. Ascasibar (AIP, Germany) and J. M. Diego (IFCA, Spain)
A phenomenological model of galaxy clusters
7 pages, 4 figures, submitted to MNRAS
null
10.1111/j.1365-2966.2007.12546.x
null
astro-ph
null
We present a simple model to describe the dark matter density, the gas density, and the gas temperature profiles of galaxy clusters. Analytical expressions for these quantities are given in terms of only five free parameters with a clear physical meaning: the mass M of the dark matter halo (or the characteristic temperature T_0), the characteristic scale radius a, the cooling radius in units of a (0<alpha<1), the central temperature in units of T_0 (0<t<1), and the asymptotic baryon fraction in units of the cosmic value (f~1). It is shown that our model is able to reproduce the three-dimensional density and temperature profiles inferred from X-ray observations of real clusters within a 20 per cent accuracy over most of the radial range. Some possible applications are briefly discussed.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 09:29:50 GMT" } ]
2009-11-13T00:00:00
[ [ "Ascasibar", "Y.", "", "AIP, Germany" ], [ "Diego", "J. M.", "", "IFCA, Spain" ] ]
0706.2559
Sofia Ramstedt
S. Ramstedt, F. L. Schoeier, H. Olofsson
The physics and chemistry of circumstellar envelopes of S-stars on the AGB
2 pages, 1 figure, to appear in Proceedings from 'Why Galaxies Care About AGB stars'
null
null
null
astro-ph
null
The S-stars have been suggested to be a brief transitional phase as stars evolve from oxygen-rich M-type stars into carbon stars, through the dredge up of carbon from He-shell burning. As possible transition objects, S-stars might help achieve a deeper understanding of the chemical evolution as a star ascends the AGB, as well as shed more light on the mass-loss mechanism. We have initiated a large survey of 40 S-stars to observe line emission in common molecules such as CO, SiO, HCN, CS and SiS. Detailed radiative transfer modelling of multi-transition CO radio line observations towards a sample of 40 S-stars shows that the mass-loss rate distribution of S-stars is consistent with those found for M-type AGB stars and carbon stars. Initial results from modelling of the circumstellar SiO emission are also presented.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 09:32:42 GMT" } ]
2007-06-19T00:00:00
[ [ "Ramstedt", "S.", "" ], [ "Schoeier", "F. L.", "" ], [ "Olofsson", "H.", "" ] ]
0706.2560
Balasubramanian Ananthanarayan
B. Ananthanarayan, P. N. Pandita
Sparticle Mass Spectrum in Grand Unified Theories
19 pages, 6 figures
Int.J.Mod.Phys.A22:3229-3259,2007
10.1142/S0217751X07036889
null
hep-ph
null
We carry out a detailed analysis of sparticle mass spectrum in supersymmetric grand unified theories. We consider the spectroscopy of the squarks and sleptons in SU(5) and SO(10) grand unified theories, and show how the underlying supersymmetry breaking parameters of these theories can be determined from a measurement of different sparticle masses. This analysis is done analytically by integrating the one-loop renormalization group equations with appropriate boundary conditions implied by the underlying grand unified gauge group. We also consider the impact of non-universal gaugino masses on the sparticle spectrum, especially the neutralino and chargino masses which arise in supersymmetric grand unified theories with non-minimal gauge kinetic function. In particular, we study the interrelationships between the squark and slepton masses which arise in grand unified theories at the one-loop level, which can be used to distinguish between the different underlying gauge groups and their breaking pattern to the Standard Model gauge group. We also comment on the corrections that can affect these one-loop results.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 09:33:01 GMT" } ]
2008-11-26T00:00:00
[ [ "Ananthanarayan", "B.", "" ], [ "Pandita", "P. N.", "" ] ]
0706.2561
Jan Timmermans
The DELPHI Collaboration, J. Abdallah, et al
Study of multi-muon bundles in cosmic ray showers detected with the DELPHI detector at LEP
22 pages, 17 figures, Accepted by Astropart. Phys
Astropart.Phys.28:273-286,2007
10.1016/j.astropartphys.2007.06.001
CERN-PH-EP/2007-008
astro-ph hep-ex
null
The DELPHI detector at LEP has been used to measure multi-muon bundles originating from cosmic ray interactions with air. The cosmic events were recorded in ``parasitic mode'' between individual e+e- interactions and the total live time of this data taking is equivalent to 1.6x10^6 seconds. The DELPHI apparatus is located about 100 metres underground and the 84 metres rock overburden imposes a cut-off of about 52 GeV/c on muon momenta. The data from the large volume Hadron Calorimeter allowed the muon multiplicity of 54201 events to be reconstructed. The resulting muon multiplicity distribution is compared with the prediction of the Monte Carlo simulation based on CORSIKA/QGSJET01. The model fails to describe the abundance of high multiplicity events. The impact of QGSJET internal parameters on the results is also studied.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 09:37:01 GMT" } ]
2008-11-26T00:00:00
[ [ "The DELPHI Collaboration", "", "" ], [ "Abdallah", "J.", "" ] ]
0706.2562
Tim Roberts
T.P. Roberts (Durham University)
X-ray observations of ultraluminous X-ray sources
Invited talk at the 5th Stromlo Symposium. 10 pages, 4 figures. Accepted for publication in Astrophysics & Space Science
Astrophys.SpaceSci.311:203-212,2007
10.1007/s10509-007-9547-z
null
astro-ph
null
Ultraluminous X-ray sources (ULXs) are amongst the most intriguing of X-ray source classes. Their extreme luminosities - greater than 10^39 erg/s in the 0.3 - 10 keV band alone - suggest either the presence of black holes larger than those regularly encountered in our own Galaxy (the Galactic centre excepted), or sources apparently radiating well above the Eddington limit. We review the insights afforded us by studies of their X-ray emission, focussing on what this reveals about the underlying compact object. In particular, we discuss recent deep observations of ULXs by the XMM-Newton observatory, and how the unprecedented data quality provided by this mission is starting to discriminate between the different physical models for these extraordinary X-ray emitters.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 09:46:01 GMT" } ]
2008-11-26T00:00:00
[ [ "Roberts", "T. P.", "", "Durham University" ] ]
0706.2563
Meltem Gungormez
Meltem Gungormez and Hasan R. Karadayi
On Poincare Polynomials of Hyperbolic Lie Algebras
14 pages, 7 Figures, Plain TeX
null
null
null
math-ph hep-th math.GR math.MP math.RT
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We have general frameworks to obtain Poincare polynomials for Finite and also Affine types of Kac-Moody Lie algebras. Very little is known however beyond Affine ones, though we have a constructive theorem which can be applied both for finite and infinite cases. One can conclusively said that theorem gives the Poincare polynomial P(G) of a Kac-Moody Lie algebra G in the product form P(G)=P(g) R where g is a precisely chosen sub-algebra of G and R is a rational function. Not in the way which theorem says but, at least for 48 hyperbolic Lie algebras considered in this work, we have shown that there is another way of choosing a sub-algebra in such a way that R appears to be the inverse of a finite polynomial. It is clear that a rational function or its inverse can not be expressed in the form of a finite polynomial. Our method is based on numerical calculations and results are given for each and every one of 48 Hyperbolic Lie algebras. In an illustrative example however, we will give how above-mentioned theorem gives us rational functions in which case we find a finite polynomial for which theorem fails to obtain.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 09:52:46 GMT" }, { "version": "v2", "created": "Wed, 9 Jun 2010 20:57:31 GMT" } ]
2021-05-21T00:00:00
[ [ "Gungormez", "Meltem", "" ], [ "Karadayi", "Hasan R.", "" ] ]
0706.2564
Sebastian Jester
Sebastian Jester (1,2), Klaus Meisenheimer (1), Andre' Martel (3), Eric Perlman (4), Bill Sparks (5) ((1) MPIA Heidelberg, (2) Fermilab Particle Astrophysics Center, (3) JHU, (4) FIT, (5) STScI)
Hubble Space Telescope far-ultraviolet imaging of the jet in 3C273: a common emission component from optical to X-rays
MNRAS accepted; 8 pages, 4 .eps files
Mon.Not.Roy.Astron.Soc.380:828-834,2007
10.1111/j.1365-2966.2007.12120.x
FERMILAB-PUB-07-071-CD
astro-ph
null
We present far-ultraviolet (UV) observations at 150 nm of the jet of the quasar 3C 273 obtained with the Advanced Camera for Survey's Solar Blind Channel (ACS/SBC) on board the Hubble Space Telescope. While the jet morphology is very similar to that in the optical and near-ultraviolet, the spectral energy distributions (SEDs) of the jet's sub-regions show an upturn in nu f_nu at 150 nm compared to 300 nm everywhere in the jet. Moreover, the 150 nm flux is compatible with extrapolating the X-ray power-law down to the ultra-violet region. This constitutes strong support for a common origin of the jet's far-UV and X-ray emission. It implies that even a substantial fraction of the *visible light* in the X-ray brightest parts of the jet arises from the same spectral component as the X-rays, as had been suggested earlier based on Spitzer Space Telescope observations. We argue that the identification of this UV/X-ray component opens up the possibility to establish the synchrotron origin of the X-ray emission by optical polarimetry.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 10:07:36 GMT" } ]
2014-11-18T00:00:00
[ [ "Jester", "Sebastian", "" ], [ "Meisenheimer", "Klaus", "" ], [ "Martel", "Andre'", "" ], [ "Perlman", "Eric", "" ], [ "Sparks", "Bill", "" ] ]
0706.2565
Jan Timmermans
The DELPHI Collaboration, J. Abdallah, et al
Zgamma* production in e+e- interactions at sqrt{s} = 183 - 209 GeV
38 pages, 13 figures, Accepted by Eur. Phys. J. C
Eur.Phys.J.C51:503-523,2007
10.1140/epjc/s10052-007-0339-y
CERN-PH-EP/2006-022
hep-ex
null
Measurements of Zgamma* production are presented using data collected by the DELPHI detector at centre-of-mass energies ranging from 183 to 209 GeV, corresponding to an integrated luminosity of about 667 pb^{-1}. The measurements cover a wide range of the possible final state four-fermion configurations: hadronic and leptonic (e+ e- q qbar, mu+ mu- q qbar, q qbar nu nubar), fully leptonic (l+ l- l'+ l'-) and fully hadronic final states (q qbar q qbar, with a low mass q qbar pair). Measurements of the Zgamma* cross-section for the various final states have been compared with the Standard Model expectations and found to be consistent within the errors. In addition, a total cross-section measurement of the l+ l- l'+ l'- cross-section is reported, and found to be in agreement with the prediction of the Standard Model.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:04:29 GMT" } ]
2008-11-26T00:00:00
[ [ "The DELPHI Collaboration", "", "" ], [ "Abdallah", "J.", "" ] ]
0706.2566
Martin Dominik
M. Dominik (SUPA, University of St Andrews), N. J. Rattenbury, A. Allan, S. Mao, D. M. Bramich, M. J. Burgdorf, E. Kerins, Y. Tsapras, L. Wyrzykowski
An anomaly detector with immediate feedback to hunt for planets of Earth mass and below by microlensing
13 pages, 4 figures and 1 table. Accepted for publication in MNRAS
null
10.1111/j.1365-2966.2007.12124.x
null
astro-ph
null
(abridged) The discovery of OGLE 2005-BLG-390Lb, the first cool rocky/icy exoplanet, impressively demonstrated the sensitivity of the microlensing technique to extra-solar planets below 10 M_earth. A planet of 1 M_earth in the same spot would have provided a detectable deviation with an amplitude of ~ 3 % and a duration of ~ 12 h. An early detection of a deviation could trigger higher-cadence sampling which would have allowed the discovery of an Earth-mass planet in this case. Here, we describe the implementation of an automated anomaly detector, embedded into the eSTAR system, that profits from immediate feedback provided by the robotic telescopes that form the RoboNet-1.0 network. It went into operation for the 2007 microlensing observing season. As part of our discussion about an optimal strategy for planet detection, we shed some new light on whether concentrating on highly-magnified events is promising and planets in the 'resonant' angular separation equal to the angular Einstein radius are revealed most easily. Given that sub-Neptune mass planets can be considered being common around the host stars probed by microlensing (preferentially M- and K-dwarfs), the higher number of events that can be monitored with a network of 2m telescopes and the increased detection efficiency for planets below 5 M_earth arising from an optimized strategy gives a common effort of current microlensing campaigns a fair chance to detect an Earth-mass planet (from the ground) ahead of the COROT or Kepler missions. The detection limit of gravitational microlensing extends even below 0.1 M_earth, but such planets are not very likely to be detected from current campaigns. However, these will be within the reach of high-cadence monitoring with a network of wide-field telescopes or a space-based telescope.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 10:14:45 GMT" } ]
2009-11-13T00:00:00
[ [ "Dominik", "M.", "", "SUPA, University of St Andrews" ], [ "Rattenbury", "N. J.", "" ], [ "Allan", "A.", "" ], [ "Mao", "S.", "" ], [ "Bramich", "D. M.", "" ], [ "Burgdorf", "M. J.", "" ], [ "Kerins", "E.", "" ], [ "Tsapras", "Y.", "" ], [ "Wyrzykowski", "L.", "" ] ]
0706.2567
Maria T. Beltran
M.T. Beltran (1), R. Cesaroni (2), L. Moscadelli (2), and C. Codella (3) ((1) Universitat de Barcelona; (2) Osservatorio di Arcetri; (3) IRA-Firenze)
The hyperyoung HII region in G24.78+0.08 A1
4 pages, 5 figures. Accepted for publication by A&A Letter
null
10.1051/0004-6361:20077974
null
astro-ph
null
Context. G24.78+0.08 A1 is a 20 Msun star surrounded by a hypercompact (HC) HII region, driving a CO bipolar outflow, and located at the center of a massive rotating toroid undergoing infall towards the HC region. Recent water maser observations suggest that the HC region is expanding and accretion onto the star is halted. Aims. This study aims to confirm the expansion scenario proposed for the HC region on the basis of recent H2O maser observations. Methods. We carried out continuum VLA observations at 1.3cm and 7mm with the A array plus Pie Town configuration to map the HC region towards G24 A1. Results. The emission of the HC region has been resolved and shows a ring shape structure. The profiles of the emission obtained by taking slices at different angles passing through the barycenter of the HC region confirm the shell structure of the emission. The ratio between the inner and the outer radius of the shell, Ri/Ro, derived fitting the normalized brightness temperature profile passing through the peak of the 7mm emission, is 0.9, which indicates that the shell is thin. The deconvolved outer radius estimated from the fit is 590 AU. These results imply that the HC region in G24 A1 cannot be described in terms of a classical, homogeneous HII region but is instead an ionized shell. This gives support to the model of an expanding wind-driven, ionized shell suggested by the kinematics and distribution of the H2O masers associated with the HC region. According to this model, the HC region is expanding on very short times scales, 21-66 yr.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 10:27:05 GMT" } ]
2009-11-13T00:00:00
[ [ "Beltran", "M. T.", "" ], [ "Cesaroni", "R.", "" ], [ "Moscadelli", "L.", "" ], [ "Codella", "C.", "" ] ]
0706.2568
Kaustubh Priolkar
K. R. Priolkar and R. Rawat
Effect of Hetrovalent substitution at Mn site on the Magnetic and Transport Properties of La$_{0.67}$Sr$_{0.33}$MnO$_3$
11 pages, 8 figures, accepted in J. Magn. Magn. Magn. Mater
null
10.1016/j.jmmm.2007.06.007
null
cond-mat.str-el
null
Magnetic and transport properties of Ti substituted La$_{0.67}$Sr$_{0.33}$MnO$_3$ are drastically affected with a change in preparation conditions. Low temperature infra-red absorption measurements reveal that this is perhaps due to inhomogeniety in substitution of Ti$^{4+}$ on Mn sites. It is found that, in the high temperature annealed samples, the substitution of Ti supresses the double exchange interaction due to the formation of Mn$^{3+}$-O-Ti$^{4+}$ chains. While in the low temperature annealed case substitution of Ti causes formation of isolated ferromagnetic clusters linked to each other by a variable range hopping polaron.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 10:28:52 GMT" } ]
2009-11-13T00:00:00
[ [ "Priolkar", "K. R.", "" ], [ "Rawat", "R.", "" ] ]
0706.2569
Leif Lonnblad
J. Alwall, S. Hoeche, F. Krauss, N. Lavesson, L. Lonnblad, F. Maltoni, M.L. Mangano, M. Moretti, C.G. Papadopoulos, F. Piccinini, S. Schumann, M. Treccani, J. Winter, M. Worek
Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions
null
Eur.Phys.J.C53:473-500,2008
10.1140/epjc/s10052-007-0490-5
null
hep-ph
null
We compare different procedures for combining fixed-order tree-level matrix-element generators with parton showers. We use the case of W-production at the Tevatron and the LHC to compare different implementations of the so-called CKKW and MLM schemes using different matrix-element generators and different parton cascades. We find that although similar results are obtained in all cases, there are important differences.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 10:31:19 GMT" }, { "version": "v2", "created": "Wed, 16 Jan 2008 17:24:24 GMT" } ]
2008-11-26T00:00:00
[ [ "Alwall", "J.", "" ], [ "Hoeche", "S.", "" ], [ "Krauss", "F.", "" ], [ "Lavesson", "N.", "" ], [ "Lonnblad", "L.", "" ], [ "Maltoni", "F.", "" ], [ "Mangano", "M. L.", "" ], [ "Moretti", "M.", "" ], [ "Papadopoulos", "C. G.", "" ], [ "Piccinini", "F.", "" ], [ "Schumann", "S.", "" ], [ "Treccani", "M.", "" ], [ "Winter", "J.", "" ], [ "Worek", "M.", "" ] ]
0706.2570
Marian Ioan Munteanu Dr
Raluca Mocanu and Marian Ioan Munteanu
Gray Curvature Identities for Almost Contact Metric Manifolds
13 pages
Journal of Korean Mathematical Society, 47 (2010), 505-521
null
null
math.DG
null
The aim of this research is the study of Gray curvature identities, introduced by Alfred Gray in \cite{kn:Gra76} for the class of almost hermitian manifolds. As known till now, there is no equivalent for the class of almost contact manifolds. For this purpose we use the Boohby-Wang fibration and the warped manifolds construction in order to establish which identities could be satisfied by an almost contact manifold.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 10:31:22 GMT" } ]
2010-05-04T00:00:00
[ [ "Mocanu", "Raluca", "" ], [ "Munteanu", "Marian Ioan", "" ] ]
0706.2571
Santiago Torres
J. Camacho, S. Torres, J. Isern, L.G. Althaus, E. Garcia-Berro
The contribution of Oxygen-Neon white dwarfs to the MACHO content of the Galactic Halo
10 pages, 4 figures. Accepted for publication in Astronomy & Astrophysics
null
10.1051/0004-6361:20077714
null
astro-ph
null
The interpretation of microlensing results towards the Large Magellanic Cloud (LMC) still remains controversial. White dwarfs have been proposed to explain these results and, hence, to contribute significantly to the mass budget of our Galaxy. However, several constraints on the role played by regular carbon-oxygen white dwarfs exist. Massivewhite dwarfs are thought to be made of a mixture of oxygen and neon. Correspondingly, their cooling rate is larger than those of typical carbon-oxygen white dwarfs and they fade to invisibility in short timescales. Consequently, they constitute a good candidate for explaining the microlensing results. Here, we examine in detail this hypothesis by using the most recent and up-to-date cooling tracks for massive white dwarfs and a Monte Carlo simulator which takes into account the most relevant Galactic inputs. We find that oxygen-neon white dwarfs cannot account for a substantial fraction of the microlensing depth towards the LMC, independently of the adopted initial mass function, although some microlensing events could be due to oxygen--neon white dwarfs. The white dwarf population contributes at most a 5% to the mass of the Galactic halo.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 10:37:28 GMT" } ]
2009-11-13T00:00:00
[ [ "Camacho", "J.", "" ], [ "Torres", "S.", "" ], [ "Isern", "J.", "" ], [ "Althaus", "L. G.", "" ], [ "Garcia-Berro", "E.", "" ] ]
0706.2572
Carlo Luciano Bianco
Remo Ruffini, Maria Grazia Bernardini, Carlo Luciano Bianco, Letizia Caito, Pascal Chardonnet, Maria Giovanna Dainotti, Federico Fraschetti, Roberto Guida, Michael Rotondo, Gregory Vereshchagin, Luca Vitagliano, She-Sheng Xue
The Blackholic energy and the canonical Gamma-Ray Burst
163 pages, 89 figures, to appear on the "Proceedings of the XIIth Brazilian School of Cosmology and Gravitation", M. Novello, S.E. Perez-Bergliaffa (editors), AIP, in press
AIP Conf.Proc.910:55-217,2007
10.1063/1.2752480
null
astro-ph
null
We outline the main results of our GRB model, based on the three interpretation paradigms we proposed in July 2001, comparing and contrasting them with the ones in the current literature. Thanks to the observations by Swift and by VLT, this analysis points to a "canonical GRB" originating from markedly different astrophysical scenarios. The communality is that they are all emitted in the formation of a black hole with small or null angular momentum. The following sequence appears to be canonical: the vacuum polarization process creating an optically thick self accelerating electron-positron plasma; the engulfment of baryonic mass during the plasma expansion; the adiabatic expansion of the optically thick "fireshell" up to the transparency; the interaction of the remaining accelerated baryons with the interstellar medium (ISM). This leads to the canonical GRB composed of a proper GRB (P-GRB), emitted at the moment of transparency, followed by an extended afterglow. The parameters are the plasma total energy, the fireshell baryon loading and the ISM filamentary distribution around the source. In the limit of no baryon loading the total energy is radiated in the P-GRB. In this limit, the canonical GRBs explain as well the short GRBs.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 14:18:09 GMT" } ]
2011-07-19T00:00:00
[ [ "Ruffini", "Remo", "" ], [ "Bernardini", "Maria Grazia", "" ], [ "Bianco", "Carlo Luciano", "" ], [ "Caito", "Letizia", "" ], [ "Chardonnet", "Pascal", "" ], [ "Dainotti", "Maria Giovanna", "" ], [ "Fraschetti", "Federico", "" ], [ "Guida", "Roberto", "" ], [ "Rotondo", "Michael", "" ], [ "Vereshchagin", "Gregory", "" ], [ "Vitagliano", "Luca", "" ], [ "Xue", "She-Sheng", "" ] ]
0706.2573
Roberto Mignani
R.P.Mignani (MSSL.Ucl), R.Perna (JILA, UCB), N. Rea (SRON), G.L. Israel (INAF-Oar), S. Mereghetti (INAF-Iasf), G. Lo Curto (ESO)
VLT/NACO observations of the High-Magnetic field radio pulsar PSR J1119-6127
8 pages, 4 figures, A&A, in press
null
10.1051/0004-6361:20077486
null
astro-ph
null
Recent radio observations have unveiled the existence of a number of radio pulsars with spin-down derived magnetic fields in the magnetar range. However, their observational properties appears to be more similar to classical radio pulsars than to magnetars. To shed light on this puzzle we first have to determine whether the spin-down derived magnetic field values for these radio pulsars are indeed representative of the actual neutron star magnetic field or if they are polluted, e.g. by the effects of a torque from a fallback disk. To investigate this possibility, we have performed deep IR observations of one of these high magnetic field radio pulsars (PSR J1119-6127) with the ESO VLT to search for IR emission which can be associated with a disk. No IR emission is detected from the pulsar position down to J=24, H=23, Ks=22. By comparing our flux upper limits with the predictions of fallback disk models, we have found that we can only exclude the presence of a disk with accretion rate dot M >3x10^16 g/s. This lower limit cannot rule out the presence of a substantial disk torque on the pulsar, which would then lead to overestimate the value of the magnetic field inferred from P and dot P.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 10:47:56 GMT" } ]
2009-11-13T00:00:00
[ [ "Mignani", "R. P.", "", "MSSL.Ucl" ], [ "Perna", "R.", "", "JILA, UCB" ], [ "Rea", "N.", "", "SRON" ], [ "Israel", "G. L.", "", "INAF-Oar" ], [ "Mereghetti", "S.", "", "INAF-Iasf" ], [ "Curto", "G. Lo", "", "ESO" ] ]
0706.2574
Stefanie Komossa
Dawei Xu (1), Stefanie Komossa (2), Hongyan Zhou (3,2,4), Tinggui Wang (4), Jianyan Wei (1) ((1) NAOC, (2) MPE, (3) Univ. of Florida, (4) USTC)
The narrow-line region of narrow-line and broad-line type 1 AGN I. A zone of avoidance in density
submitted to ApJ (April 2007); 42 pages, 10 figures
null
10.1086/521697
null
astro-ph
null
The properties of narrow-line Seyfert 1 (NLS1) galaxies, the links and correlations between them, and the physics behind them, are still not well understood. Apart from accretion rates and black hole masses, density and outflows were speculated to be among the main drivers of the NLS1 phenomenon. Here, we utilize the diagnostic power of the [SII]6716,6731 intensity ratio to measure the density of the NLR systematically and homogeneously for a large sample of NLS1 galaxies, and we perform a comparison with a sample of broad-line type 1 AGN. We report the discovery of a zone of avoidance in density in the sense that AGN with broad lines (FWHM_Hbeta > 2000 km/s) avoid low densities, while NLS1 galaxies show a wider distribution in the NLR density, including a significant number of objects with low densities. A correlation analysis further shows that the Eddington ratio L/L_Edd anti-correlates with density. We investigate a number of different models for the zone of avoidance in density. Supersolar metallicities and temperature effects, a strong starburst contribution in NLS1 galaxies, different NLR extents and selective obscuration are considered unlikely. Possible differences in the fraction of matter-bounded clouds and differences in the interstellar media of the host galaxies of NLS1 galaxies and broad-line Seyfert 1 (BLS1) galaxies can only be tested further with future observations. We tentatively favor the effects of winds/outflows, stronger in NLS1 galaxies than in BLS1 galaxies, to explain the observations.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 10:48:21 GMT" } ]
2009-11-13T00:00:00
[ [ "Xu", "Dawei", "", "NAOC" ], [ "Komossa", "Stefanie", "", "MPE" ], [ "Zhou", "Hongyan", "", "Univ. of Florida", "MPE", "USTC" ], [ "Wang", "Tinggui", "", "USTC" ], [ "Wei", "Jianyan", "", "NAOC" ] ]
0706.2575
Kettani Omar
O.Kettani
A new lower bound on the independence number of a graph
4 pages
null
null
null
cs.DM
null
For a given connected graph G on n vertices and m edges, we prove that its independence number is at least (2m+n+2-sqrt(sqr(2m+n+2)-16sqr(n)))/8.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 10:50:27 GMT" }, { "version": "v2", "created": "Wed, 20 Jun 2007 17:59:06 GMT" } ]
2007-06-20T00:00:00
[ [ "Kettani", "O.", "" ] ]
0706.2576
David d'Enterria
X. Aslanoglou, A. Cyz, N. Davis, D. d'Enterria, E. Gladysz-Dziadus, C. Kalfas, Y. Musienko, A. Kuznetsov, A.D. Panagiotou
First performance studies of a prototype for the CASTOR forward calorimeter at the CMS experiment
24 pages, 19 figs. CERN-CMS Note 2006-142. Minor updates
ActaPhys.Polon.B39:1429-1454,2008
null
null
physics.ins-det nucl-ex
null
We present results on the performance of the first prototype of the CASTOR quartz-tungsten sampling calorimeter, to be installed in the very forward region of the CMS experiment at the LHC. This study includes GEANT Monte Carlo simulations of the Cherenkov light transmission efficiency of different types of air-core light guides, as well as analysis of the calorimeter linearity and resolution as a function of energy and impact-point, obtained with 20-200 GeV electron beams from CERN/SPS tests in 2003. Several configurations of the calorimeter have been tested and compared, including different combinations of (i) structures for the active material of the calorimeter (quartz plates and fibres), (ii) various light-guide reflecting materials (glass and foil reflectors) and (iii) photodetector devices (photomultipliers and avalanche photodiodes).
[ { "version": "v1", "created": "Sun, 17 Jun 2007 16:46:56 GMT" }, { "version": "v2", "created": "Wed, 20 Jun 2007 12:14:24 GMT" }, { "version": "v3", "created": "Mon, 12 Nov 2007 13:41:46 GMT" } ]
2008-11-26T00:00:00
[ [ "Aslanoglou", "X.", "" ], [ "Cyz", "A.", "" ], [ "Davis", "N.", "" ], [ "d'Enterria", "D.", "" ], [ "Gladysz-Dziadus", "E.", "" ], [ "Kalfas", "C.", "" ], [ "Musienko", "Y.", "" ], [ "Kuznetsov", "A.", "" ], [ "Panagiotou", "A. D.", "" ] ]
0706.2577
Gustav Delius
R. S. Kemble
A Groshev Theorem for Small Linear Forms
null
Mathematika 52 (2006) 79-85
null
null
math.NT
null
In this paper the absolute value or distance from the origin analogue of the classical Khintchine-Groshev theorem is established for a single linear form with a `slowly decreasing' error function.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:03:38 GMT" } ]
2007-06-19T00:00:00
[ [ "Kemble", "R. S.", "" ] ]
0706.2578
Yuri Andreev
Yu. Andreev, N. Krasnikov and A. Toropin
Using the $e^\pm \mu^\mp + E^{miss}_T$ and $l^+l^- + E^{miss}_T$ Signatures in the Search for Supersymmetry and Constraining the MSSM model at LHC
26 pages, 13 figures
null
null
null
hep-ph
null
We study the $e^{\pm}\mu^{\mp} + E^{miss}_T$ and $l^+l^- + E^{miss}_T$ signatures $(l = e, \mu)$ for different values of $\tan\beta$ in the mSUGRA model. With $\tan\beta$ rising, we observe a characteristic change in the shape of dilepton mass spectra in $l^+l^- + E^{miss}_T $ versus $e^{\pm}\mu^{\mp}$ final states reflecting the decrease of $\tilde{\chi}^0_2 \to l^+l^- \tilde{\chi^0_1}$ branching ratio. We also study the non mSUGRA modifications of the CMS test point LM1 with arbitrary relations among gaugino and higgsino masses. For such modifications of the mSUGRA test point LM1 the number of lepton events depends rather strongly on the relations among gaugino and higgsino masses and in some modifications of the test point LM1 the signatures with leptons and $E_{T}^{miss}$ do not lead to the SUSY discovery and the single SUSY discovery signature remains the signature with $n \geq 2 jets + E^{miss}_T + no leptons$.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:07:21 GMT" } ]
2007-06-19T00:00:00
[ [ "Andreev", "Yu.", "" ], [ "Krasnikov", "N.", "" ], [ "Toropin", "A.", "" ] ]
0706.2579
Jouni Parkkonen
Jouni Parkkonen and Fr\'ed\'eric Paulin
Prescribing the behaviour of geodesics in negative curvature
89 pages
Geom. Topol. 14 (2010) 277-392
10.2140/gt.2010.14.277
University of Jyv\"askyl\"a Preprint 344
math.DG math.MG math.NT
null
Given a family of (almost) disjoint strictly convex subsets of a complete negatively curved Riemannian manifold M, such as balls, horoballs, tubular neighborhoods of totally geodesic submanifolds, etc, the aim of this paper is to construct geodesic rays or lines in M which have exactly once an exactly prescribed (big enough) penetration in one of them, and otherwise avoid (or do not enter too much in) them. Several applications are given, including a definite improvement of the unclouding problem of [PP1], the prescription of heights of geodesic lines in a finite volume such M, or of spiraling times around a closed geodesic in a closed such M. We also prove that the Hall ray phenomenon described by Hall in special arithmetic situations and by Schmidt-Sheingorn for hyperbolic surfaces is in fact only a negative curvature property.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:38:17 GMT" } ]
2014-11-11T00:00:00
[ [ "Parkkonen", "Jouni", "" ], [ "Paulin", "Frédéric", "" ] ]
0706.2580
Carlos Gutierrez
Bego\~na Alarc\'on, Carlos Gutierrez, Jos\'e Mart\'inez-Alfaro
Planar maps whose second iterate has a unique fixed point
13 pages, no figures
null
null
null
math.DS math.CA
null
Let a>0, F: R^2 -> R^2 be a differentiable (not necessarily C^1) map and Spec(F) be the set of (complex) eigenvalues of the derivative F'(p) when p varies in R^2. (a) If Spec(F) is disjoint of the interval [1,1+a[, then Fix(F) has at most one element, where Fix(F) denotes the set of fixed points of F. (b) If Spec(F) is disjoint of the real line R, then Fix(F^2) has at most one element. (c) If F is a C^1 map and, for all p belonging to R^2, the derivative F'(p) is neither a homothety nor has simple real eigenvalues, then Fix(F^2) has at most one element, provided that Spec(F) is disjoint of either (c1) the union of the number 0 with the intervals ]-\infty, -1] and [1,\infty[, or (c2) the interval [-1-a, 1+a]. Conditions under which Fix(F^n), with n>1, is at most unitary are considered.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:24:12 GMT" } ]
2007-06-19T00:00:00
[ [ "Alarcón", "Begoña", "" ], [ "Gutierrez", "Carlos", "" ], [ "Martínez-Alfaro", "José", "" ] ]
0706.2581
Rutwig C. Stursberg
R. Campoamor-Stursberg
Internal labelling operators and contractions of Lie algebras
20 pages, 2 tables
J.Phys.A40:14773-14790,2007
10.1088/1751-8113/40/49/011
null
hep-th
null
We analyze under which conditions the missing label problem associated to a reduction chain $\frak{s}^{\prime}\subset \frak{s}$ of (simple) Lie algebras can be completely solved by means of an In\"on\"u-Wigner contraction $\frak{g}$ naturally related to the embedding. This provides a new interpretation of the missing label operators in terms of the Casimir operators of the contracted algebra, and shows that the available labeling operators are not completely equivalent. Further, the procedure is used to obtain upper bounds for the number of invariants of affine Lie algebras arising as contractions of semisimple algebras.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:29:33 GMT" } ]
2008-11-26T00:00:00
[ [ "Campoamor-Stursberg", "R.", "" ] ]
0706.2582
O. S. Barisic
O. S. Barisic
Diagrammatic content of the DMFT for the Holstein polaron problem in finite dimensions
5 pages, 3 figures
Phys. Rev. B 76, 193106 (2007)
10.1103/PhysRevB.76.193106
null
cond-mat.str-el
null
In the context of the Holstein polaron problem it is shown that the dynamical mean field theory (DMFT) corresponds to the summation of a special class of local diagrams in the skeleton expansion of the self-energy. In the real space representation, these local diagrams are characterized by the absence of vertex corrections involving phonons at different lattice sites. Such corrections vanish in the limit of infinite dimensions, for which the DMFT provides the exact solution of the Holstein polaron problem. However, for finite dimensional systems the accuracy of the DMFT is limited. In particular, it cannot describe correctly the adiabatic spreading of the polaron over multiple lattice sites. Arguments are given that the DMFT limitations on vertex corrections found for the Holstein polaron problem persist for finite electron densities and arbitrary phonon dispersion.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:31:31 GMT" }, { "version": "v2", "created": "Fri, 26 Oct 2007 14:10:21 GMT" } ]
2013-05-29T00:00:00
[ [ "Barisic", "O. S.", "" ] ]
0706.2583
Phuong Mai Dinh
F. Fehrer, P.M. Dinh, M. Baer, P.-G. Reinhard, and E. Suraud
Hindered Coulomb explosion of embedded Na clusters -- stopping, shape dynamics and energy transport
12 pages, 10 figures, accepted in Euro. Phys. J. D
Euro. Phys. J. D 45 (2007) 447
10.1140/epjd/e2007-00209-3
null
cond-mat.other
null
We investigate the dynamical evolution of a Na$_8$ cluster embedded in Ar matrices of various sizes from N=30 to 1048. The system is excited by an intense short laser pulse leading to high ionization stages. We analyze the subsequent highly non-linear motion of cluster and Ar environment in terms of trajectories, shapes, and energy flow. The most prominent effects are: temporary stabilization of high charge states for several ps, sudden stopping of the Coulomb explosion of the embedded Na$_8$ clusters associated with an extremely fast energy transfer to the Ar matrix, fast distribution of energy throughout the Ar layers by a sound wave. Other ionic-atomic transfer and relaxation processes proceed at slower scale of few ps. The electron cloud is almost thermally decoupled from ions and thermalizes far beyond the ps scale.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:37:54 GMT" } ]
2009-11-13T00:00:00
[ [ "Fehrer", "F.", "" ], [ "Dinh", "P. M.", "" ], [ "Baer", "M.", "" ], [ "Reinhard", "P. -G.", "" ], [ "Suraud", "E.", "" ] ]
0706.2584
Alexey Samokhvalov V.
A.V.Samokhvalov, A.S.Mel'nikov, A.I.Buzdin
Vortex States Induced by Proximity Effect in Hybrid Ferromagnet-Superconductor Systems
7 pages, 6 figures
Phys. Rev. B 76, 184519 (2007)
10.1103/PhysRevB.76.184519
null
cond-mat.supr-con
null
We consider superconductivity nucleation in multiply connected mesoscopic samples such as thin-walled cylinders or rings placed in electrical contact with a ferromagnet. The superconducting critical temperature and order parameter structure are studied on the basis of linearized Usadel equations. We suggest a mechanism of switching between the superconducting states with different vorticities caused by the exchange field and associated with the oscillatory behavior of the Cooper pair wave function in a ferromagnet.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:50:17 GMT" } ]
2009-11-29T00:00:00
[ [ "Samokhvalov", "A. V.", "" ], [ "Mel'nikov", "A. S.", "" ], [ "Buzdin", "A. I.", "" ] ]
0706.2585
Richard Mayr
Parosh Aziz Abdulla, Noomene Ben Henda, Richard Mayr
Decisive Markov Chains
32 pages, 0 figures
Logical Methods in Computer Science, Volume 3, Issue 4 (November 8, 2007) lmcs:867
10.2168/LMCS-3(4:7)2007
null
cs.LO cs.DM
null
We consider qualitative and quantitative verification problems for infinite-state Markov chains. We call a Markov chain decisive w.r.t. a given set of target states F if it almost certainly eventually reaches either F or a state from which F can no longer be reached. While all finite Markov chains are trivially decisive (for every set F), this also holds for many classes of infinite Markov chains. Infinite Markov chains which contain a finite attractor are decisive w.r.t. every set F. In particular, this holds for probabilistic lossy channel systems (PLCS). Furthermore, all globally coarse Markov chains are decisive. This class includes probabilistic vector addition systems (PVASS) and probabilistic noisy Turing machines (PNTM). We consider both safety and liveness problems for decisive Markov chains, i.e., the probabilities that a given set of states F is eventually reached or reached infinitely often, respectively. 1. We express the qualitative problems in abstract terms for decisive Markov chains, and show an almost complete picture of its decidability for PLCS, PVASS and PNTM. 2. We also show that the path enumeration algorithm of Iyer and Narasimha terminates for decisive Markov chains and can thus be used to solve the approximate quantitative safety problem. A modified variant of this algorithm solves the approximate quantitative liveness problem. 3. Finally, we show that the exact probability of (repeatedly) reaching F cannot be effectively expressed (in a uniform way) in Tarski-algebra for either PLCS, PVASS or (P)NTM.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:50:16 GMT" }, { "version": "v2", "created": "Thu, 8 Nov 2007 20:21:56 GMT" } ]
2015-07-01T00:00:00
[ [ "Abdulla", "Parosh Aziz", "" ], [ "Henda", "Noomene Ben", "" ], [ "Mayr", "Richard", "" ] ]
0706.2586
Laurent Derome
A. Putze, L. Derome, D. Maurin, M. Bu\'enerd
Nuclear Cosmic Rays propagation in the Atmosphere
Proc. of 30th International Cosmic Ray Conference, Merida, Mexico; 4 pages
null
null
null
astro-ph
null
The transport of the nuclear cosmic ray flux in the atmosphere is studied and the atmospheric corrections to be applied to the measurements are calculated. The contribution of the calculated corrections to the accuracy of the experimental results are discussed and evaluated over the kinetic energy range 10-10$^{3}$ GeV/n. The Boron (B) and Carbon (C) elements system is used as a test case. It is shown that the required corrections become largely dominant at the highest energies investigated. The results are discussed.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:51:44 GMT" } ]
2007-06-19T00:00:00
[ [ "Putze", "A.", "" ], [ "Derome", "L.", "" ], [ "Maurin", "D.", "" ], [ "Buénerd", "M.", "" ] ]
0706.2587
Peter Kroll
P. Kroll (Wuppertal Universitaet)
Electroproduction of longitudinally polarized vector mesons
4 pages, 4 figures, using dis07.cls
null
null
null
hep-ph
null
It is reported on an analysis of electroproduction of light vector mesons at small Bjorken-x within the handbag approach. The partonic subprocesses, meson electroproduction off quarks or gluons, are calculated within the modified perturbative approach in which quark transverse momenta are retained. The soft hadronic matrix elements, generalized parton distributions, are constructed from the CTEQ6 parton distribution functions by means of double distributions. The cross sections for longitudinal polarized virtual photons evaluated from this approach, are in very good agreement with experiment in a wide range of kinematics. Talk presented at the DIS2007 conference, Munich (2007)
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:52:14 GMT" } ]
2007-06-19T00:00:00
[ [ "Kroll", "P.", "", "Wuppertal Universitaet" ] ]
0706.2588
Brian Harbourne
Alessandro Gimigliano, Brian Harbourne, Monica Id\`a
Betti numbers for fat point ideals in the plane: a geometric approach
15 pages + 9 page appendix
null
null
null
math.AG math.AC
null
We consider the open problem of determining the graded Betti numbers for fat point subschemes supported at general points of the projective plane. We relate this problem to the open geometric problem of determining the splitting type of the pullback of the cotangent bundle on the plane to the normalization of certain rational plane curves. We give a conjecture for the graded Betti numbers which would determine them in all degrees but one for every fat point subscheme supported at general points of the plane. We also prove our Betti number conjecture in a broad range of cases. An appendix discusses many more cases in which our conjecture has been verified computationally and provides a new and more efficient computational approach for computing graded Betti numbers in certain degrees. It also demonstrates how to derive explicit conjectural values for the Betti numbers and how to compute splitting types.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:54:22 GMT" } ]
2007-06-19T00:00:00
[ [ "Gimigliano", "Alessandro", "" ], [ "Harbourne", "Brian", "" ], [ "Idà", "Monica", "" ] ]
0706.2589
Anatoly Beda
A. G. Beda, A. S. Gerasimov
The aligned nuclear targets for investigation of time reversal invariance violation: thermal heating and optimization of target dimension
12 pages, 3 figures
null
null
ITEP-9-06
nucl-ex
null
The thermal heating of aligned nuclear targets of HIO_3, LiIO_3 ans Sb target materials under neutron irradiation at JSNS is considered. It is shown that presently the targets of large volumes (several tens of cm^3) can be used in experiment. The optimal target dimensions are recommended for investigation with resonance neutrons. The use of proposed aligned targets at the new neutron spallation source JSNS (Japan) will make p[ossible to discover TRIV or decrease the present limit on the intensity of parity conserving time violating interaction by two-three order of magnitude.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:56:07 GMT" } ]
2007-06-19T00:00:00
[ [ "Beda", "A. G.", "" ], [ "Gerasimov", "A. S.", "" ] ]
0706.2590
Andres Asensio Ramos
A. Asensio Ramos
Extreme Value Theory and the Solar Cycle
6 pages, 4 figures, accepted for publication in A&A
null
10.1051/0004-6361:20077574
null
astro-ph
null
We investigate the statistical properties of the extreme events of the solar cycle as measured by the sunspot number. The recent advances in the methodology of the theory of extreme values is applied to the maximal extremes of the time series of sunspots. We focus on the extreme events that exceed a carefully chosen threshold and a generalized Pareto distribution is fitted to the tail of the empirical cumulative distribution. A maximum likelihood method is used to estimate the parameters of the generalized Pareto distribution and confidence levels are also given to the parameters. Due to the lack of an automatic procedure for selecting the threshold, we analyze the sensitivity of the fitted generalized Pareto distribution to the exact value of the threshold. According to the available data, that only spans the previous ~250 years, the cumulative distribution of the time series is bounded, yielding an upper limit of 324 for the sunspot number. We also estimate that the return value for each solar cycle is ~188, while the return value for a century increases to ~228. Finally, the results also indicate that the most probable return time for a large event like the maximum at solar cycle 19 happens once every ~700 years and that the probability of finding such a large event with a frequency smaller than ~50 years is very small. In spite of the essentially extrapolative character of these results, their statistical significance is very large.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 11:59:01 GMT" } ]
2009-11-13T00:00:00
[ [ "Ramos", "A. Asensio", "" ] ]
0706.2591
Cosima Schuster
Udo Schwingenschloegl and Cosima Schuster
Self-assembled Pt nanowires on Ge(001): Relaxation effects
4 pages, 2 figures, final version accepted by Europhys. Lett., minor modifications of the text
Europhysics Letters 81, 26001 (2008)
10.1209/0295-5075/81/26001
null
cond-mat.mes-hall
null
Absorption of Pt on the Ge(001) surface results in stable self-organized Pt nanowires, extending over some hundred nanometers. Based on band structure calculations within density functional theory and the generalized gradient approximation, the structural relaxation of the Ge--Pt surface is investigated. The surface reconstruction pattern obtained agrees well with findings from scanning tunneling microscopy. In particular, strong Pt--Pt dimerization is characteristical for the nanowires. The surface electronic structure is significantly perturbed due to Ge--Pt interaction, which induces remarkable shifts of Ge states towards the Fermi energy. As a consequence, the topmost Ge layers are subject to a metal-insulator transition.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 12:04:55 GMT" }, { "version": "v2", "created": "Fri, 16 Nov 2007 11:16:35 GMT" } ]
2009-11-13T00:00:00
[ [ "Schwingenschloegl", "Udo", "" ], [ "Schuster", "Cosima", "" ] ]
0706.2592
Dietrich Stauffer
Katharina Muller, Christian Schulze and Dietrich Stauffer
Inhomogeneous and self-organised temperature in Schelling-Ising model
8 pages including all figures, for Max Born Symp. Wroclaw (Poland), Sept. 2007
null
null
null
physics.soc-ph
null
The Schelling model of 1971 is a complicated version of a square-lattice Ising model at zero temperature, to explain urban segregation, based on the neighbour preferences of the residents, without external reasons. Various versions between Ising and Schelling models give about the same results. Inhomogeneous "temperatures" T do not change the results much, while a feedback between segregation and T leads to a self-organisation of an average T.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 12:32:52 GMT" } ]
2007-06-19T00:00:00
[ [ "Muller", "Katharina", "" ], [ "Schulze", "Christian", "" ], [ "Stauffer", "Dietrich", "" ] ]
0706.2593
Patrick Valageas
Patrick Valageas
Using the Zeldovich dynamics to test expansion schemes
29 pages, published in A&A
Astron. Astrophys. (2007), 476, 31
10.1051/0004-6361:20078065
null
astro-ph
null
We apply various expansion schemes that may be used to study gravitational clustering to the simple case of the Zeldovich dynamics. Using the well-known exact solution of the Zeldovich dynamics we can compare the predictions of these various perturbative methods with the exact nonlinear result and study their convergence properties. We find that most systematic expansions fail to recover the decay of the response function in the highly nonlinear regime. ``Linear methods'' lead to increasingly fast growth in the nonlinear regime for higher orders, except for Pade approximants that give a bounded response at any order. ``Nonlinear methods'' manage to obtain some damping at one-loop order but they fail at higher orders. Although it recovers the exact Gaussian damping, a resummation in the high-k limit is not justified very well as the generation of nonlinear power does not originate from a finite range of wavenumbers (hence there is no simple separation of scales). No method is able to recover the relaxation of the matter power spectrum on highly nonlinear scales. It is possible to impose a Gaussian cutoff in a somewhat ad-hoc fashion to reproduce the behavior of the exact two-point functions for two different times. However, this cutoff is not directly related to the clustering of matter and disappears in exact equal-time statistics such as the matter power spectrum. On a quantitative level, the usual perturbation theory, and the nonlinear scheme to which one adds an ansatz for the response function with such a Gaussian cutoff, are the two most efficient methods. These results should hold for the gravitational dynamics as well (this has been checked at one-loop order), since the structure of the equations of motion is identical for both dynamics.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 12:56:55 GMT" }, { "version": "v2", "created": "Thu, 29 Nov 2007 13:45:30 GMT" } ]
2009-11-13T00:00:00
[ [ "Valageas", "Patrick", "" ] ]
0706.2594
Bjorn Garbrecht
Bjorn Garbrecht, Tomislav Prokopec
Baryogenesis from the amplification of vacuum fluctuations during inflation
18 pages
Phys.Rev.D78:123501,2008
10.1103/PhysRevD.78.123501
MAN/HEP/2007/11, SPIN-07/20, ITP-UU-07/30
astro-ph
null
We propose that the baryon asymmetry of the Universe may originate from the amplification of quantum fluctuations of a light complex scalar field during inflation. CP-violation is sourced by complex mass terms, which are smaller than the Hubble rate, as well as non-standard kinetic terms. We find that, when assuming 60 e-folds of inflation, an asymmetry in accordance with observation can result for models where the energy scale of inflation is of the order of 10^16 GeV. Lower scales may be achieved when assuming substantially larger amounts of e-folds.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 12:47:40 GMT" } ]
2008-12-18T00:00:00
[ [ "Garbrecht", "Bjorn", "" ], [ "Prokopec", "Tomislav", "" ] ]
0706.2595
Charles Torossian
Charles Torossian (IMJ)
The Kashiwara-Vergne conjecture
4 figures, 24 pages
null
null
null
math.QA math.RT
null
This is a Bourbaki's seminar text. We introduce the combinatorial Kashiwara-Vergne conjecture on the Baker-Campbell-Hausdorff serie. After recalling previous results and consequences, we explain the Alekseev-Meinrenken's proof [math.QA/0506499]
[ { "version": "v1", "created": "Mon, 18 Jun 2007 13:22:39 GMT" } ]
2007-06-19T00:00:00
[ [ "Torossian", "Charles", "", "IMJ" ] ]
0706.2596
Pierre Roussel
P. Roussel (IPNO), I. Stefan (IPNO)
Is the Interpretation of Delayed-Choice Experiments Misleading?
5 pages TeX
null
null
IPNO-DR-07-04
physics.pop-ph physics.hist-ph quant-ph
null
The interpretation of an experimental realization of Wheeler's delayed-choice gedanken experiment is discussed and called into question.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 13:23:03 GMT" } ]
2007-06-19T00:00:00
[ [ "Roussel", "P.", "", "IPNO" ], [ "Stefan", "I.", "", "IPNO" ] ]
0706.2597
Hyesung Kang
Hyesung Kang, Santabrata Das, Dongsu Ryu, Jungyeon Cho
Propagation of UHE protons through a magnetized large scale structure
4 page, 3 figures, To appear in the Proceedings of the 30th ICRC, Merida, Mexico, with minor changes
J.Phys.Conf.Ser.120:062025,2008
10.1088/1742-6596/120/6/062025
null
astro-ph
null
The propagation of UHECRs is affected by the intergalactic magnetic fields that were produced during the course of the large scale structure formation of the universe. We adopt a novel model where the large scale extragalactic magnetic fields (EGMF) are estimated from local dynamic properties of the gas flows in hydrodynamic simulations of a concordance LambdaCDM universe. With the model magnetic fields, we calculate the deflection angle, time delay and energy spectrum of protons with E > 10^{19} eV that are injected at cosmological sources and then travel through the large scale structure of the universe, losing the energy due to interactions with the cosmic background radiation. Implications of this study on the origin of UHECRs are discussed.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 13:26:01 GMT" }, { "version": "v2", "created": "Wed, 22 Aug 2007 13:01:11 GMT" } ]
2008-11-26T00:00:00
[ [ "Kang", "Hyesung", "" ], [ "Das", "Santabrata", "" ], [ "Ryu", "Dongsu", "" ], [ "Cho", "Jungyeon", "" ] ]
0706.2598
Gilles Fay
Fr\'ed\'eric Guilloux (PMA, APC, LTCI), Gilles Fay (LPP, APC), Jean-Fran\c{c}ois Cardoso (PMA, LTCI)
Practical wavelet design on the sphere
null
null
null
null
math.NA astro-ph math.CA math.ST stat.TH
null
We address the question of designing isotropic analysis functions on the sphere which are perfectly limited in the spectral domain and optimally localized in the spatial domain. This work is motivated by the need of localized analysis tools in domains where the data is lying on the sphere, e.g.{} the science of the Cosmic Microwave Background. Our construction is derived from the localized frames introduced by Narcowich, Petrushev, Ward, 2006. The analysis frames are optimized for given applications and compared numerically using various criteria.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 13:30:34 GMT" } ]
2007-06-19T00:00:00
[ [ "Guilloux", "Frédéric", "", "PMA, APC, LTCI" ], [ "Fay", "Gilles", "", "LPP, APC" ], [ "Cardoso", "Jean-François", "", "PMA, LTCI" ] ]
0706.2599
Dennis Downes
D. Downes and A. Eckart
Black hole in the West Nucleus of Arp 220
Reference list updated for 2007 publications; estimated position errors increased
Astron.Astrophys.468:L57,2007
10.1051/0004-6361:20077301
null
astro-ph
null
We present new observations with the IRAM Interferometer, in its longest-baseline configuration, of the CO(2-1) line and the 1.3mm dust radiation from the Arp 220 nuclear region. The dust source in the West nucleus has a size of 0.19 x 0.13 arcsec and a 1.3mm brightness temperature of 90K. This implies that the dust ring in the West nucleus has a high opacity, with tau = 1 at 1.1mm. Not only is the dust ring itself optically thick in the submm and far-IR, but it is surrounded by the previously-known, rapidly rotating molecular disk of size 0.5 arcsec that is also optically thick in the mid-IR. The molecular ring is cooler than the hot dust disk because the CO(2-1) line is seen in absorption against the dust disk. The dust ring is massive (1E9 solar masses), compact (radius 35pc), and hot (true dust temperature 170K). It resembles rather strikingly the dust ring detected around the quasar APM 08279+52, and is most unlike the warm, extended dust sources in starburst galaxies. Because there is a strong temperature gradient from the hot dust ring to the cooler molecular disk, the heating must come from a concentrated source, an AGN accretion disk that is completely invisible at optical wavelengths, and heavily obscured in hard X-rays.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 14:13:54 GMT" } ]
2009-11-13T00:00:00
[ [ "Downes", "D.", "" ], [ "Eckart", "A.", "" ] ]
0706.2600
Jos\'e M. Figueroa-O'Farrill
Jos\'e Figueroa-O'Farrill
Deformations of M-theory Killing superalgebras
20 pages (v3: a number of signs and a couple of factors have changed without affecting the result. v4: yet more sign changes, but results remain unchanged. v5: this is becoming absurd... but the signs ought to be correct now! v6: no more sign changes, but section 5.2 on the MKK monopole has been partially rewritten and some relevant references have been added.)
Class.Quant.Grav.24:5257-5276,2007
10.1088/0264-9381/24/20/020
EMPG-07-11
hep-th math.RT
null
We classify the Lie superalgebra deformations of the Killing superalgebras of some M-theory backgrounds. We show that the Killing superalgebras of the Minkowski, Freund--Rubin and M5-brane backgrounds are rigid, whereas the ones for the M-wave, the Kaluza--Klein monopole and the M2-brane admit deformations, which we give explicitly.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 13:37:56 GMT" }, { "version": "v2", "created": "Tue, 19 Jun 2007 15:33:28 GMT" }, { "version": "v3", "created": "Fri, 13 Jul 2007 18:36:26 GMT" }, { "version": "v4", "created": "Tue, 17 Jul 2007 15:26:00 GMT" }, { "version": "v5", "created": "Wed, 18 Jul 2007 13:02:58 GMT" }, { "version": "v6", "created": "Mon, 20 Aug 2007 14:26:23 GMT" } ]
2008-11-26T00:00:00
[ [ "Figueroa-O'Farrill", "José", "" ] ]
0706.2601
Rostyslav Vlokh O
R. Vlokh
Change of Optical Properties of Space under Gravitation Field
5 pages
Ukr. J. Phys. Opt. 2004 5 27-31
10.3116/16091833/5/1/27/2004
null
physics.optics
null
It is shown that, in the model of a flat 3D space, the time (i.e., the Hubble or the gravitation constant) plays a role of a spatial property. Gravitation field of spherical central mass does not lead to a lowering of symmetry of the space and appearance of anisotropy. In particular, the relations that describe the changes in the refractive indices of the space treated as an optical medium near the massive spherical body under the influence of its gravitation field have been derived.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 13:39:38 GMT" } ]
2007-06-19T00:00:00
[ [ "Vlokh", "R.", "" ] ]
0706.2602
Hugues Berry
Benoit Siri (INRIA Futurs), Mathias Quoy (ETIS), Bruno Delord (ANIM), Bruno Cessac (INLN, INRIA Sophia Antipolis), Hugues Berry (INRIA Futurs)
Effects of Hebbian learning on the dynamics and structure of random networks with inhibitory and excitatory neurons
null
null
null
null
q-bio.NC
null
The aim of the present paper is to study the effects of Hebbian learning in random recurrent neural networks with biological connectivity, i.e. sparse connections and separate populations of excitatory and inhibitory neurons. We furthermore consider that the neuron dynamics may occur at a (shorter) time scale than synaptic plasticity and consider the possibility of learning rules with passive forgetting. We show that the application of such Hebbian learning leads to drastic changes in the network dynamics and structure. In particular, the learning rule contracts the norm of the weight matrix and yields a rapid decay of the dynamics complexity and entropy. In other words, the network is rewired by Hebbian learning into a new synaptic structure that emerges with learning on the basis of the correlations that progressively build up between neurons. We also observe that, within this emerging structure, the strongest synapses organize as a small-world network. The second effect of the decay of the weight matrix spectral radius consists in a rapid contraction of the spectral radius of the Jacobian matrix. This drives the system through the ``edge of chaos'' where sensitivity to the input pattern is maximal. Taken together, this scenario is remarkably predicted by theoretical arguments derived from dynamical systems and graph theory.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 13:42:16 GMT" } ]
2007-06-19T00:00:00
[ [ "Siri", "Benoit", "", "INRIA Futurs" ], [ "Quoy", "Mathias", "", "ETIS" ], [ "Delord", "Bruno", "", "ANIM" ], [ "Cessac", "Bruno", "", "INLN, INRIA Sophia Antipolis" ], [ "Berry", "Hugues", "", "INRIA Futurs" ] ]
0706.2603
Antonio Cassa
Antonio Cassa
All quantum expectation values as classical statistical mean values
null
null
null
null
quant-ph
null
Given a physical quantum system described by a Hilbert H, for any bounded quantum observable (a bounded self-adjoint operator) T it is possible to define several ''hidden observable'' functions f:H->R associated to T and for any quantum mixed state (a density matrix) D it is possible to define several ''hidden mixed states'' (probability measures) m on H associated to D in such a way that the following equality is verified: Trace[ b(T). D] =integral[b(f(psi)).dm(psi) whatever is the continuous function b:R->R. This formula gives a general way to express any expectation value computable in a quantum theory as a classical statistical mean value.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 13:52:28 GMT" }, { "version": "v2", "created": "Sun, 18 Nov 2007 18:57:57 GMT" } ]
2007-11-18T00:00:00
[ [ "Cassa", "Antonio", "" ] ]
0706.2604
Rostyslav Vlokh O
D. Adamenko, I. Klymiv, V.M. Duda, R. Vlokh, O.Vlokh
Electrically and magnetically induced optical rotation in Pb5Ge3O11:Cr crystals at the phase transition. 2. Faraday effect in pure and Cr-doped lead germanate in the presence of electric field and spontaneous polarization
9 pages, 4 figures
Ukr. J. Phys. Opt. 2007 8 98-105
10.3116/16091833/8/2/98/2007
null
cond-mat.mtrl-sci
null
This work presents the results for the Faraday rotation in pure and Cr-doped lead germanate crystals studied in the course of proper ferroelectric phase transition. We show that the increment of the Faraday rotation appearing at the phase transition is caused by a combined magneto-electrooptic effect induced by spontaneous polarization. It is proportional to the square of spontaneous polarization. The phenomenon revealed by us corresponds to combined effects of crystal optics, which appear due to common action of different fields.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 13:56:59 GMT" } ]
2007-06-19T00:00:00
[ [ "Adamenko", "D.", "" ], [ "Klymiv", "I.", "" ], [ "Duda", "V. M.", "" ], [ "Vlokh", "R.", "" ], [ "Vlokh", "O.", "" ] ]
0706.2605
Juan Carlos Pardo Millan
Loic Chaumont (LAREMA), Juan Carlos Pardo Millan (PMA)
On the genealogy on conditioned stable L\'evy forest
null
null
null
null
math.PR
null
We give a realization of the stable L\'evy forest of a given size conditioned by its mass from the path of the unconditioned forest. Then, we prove an invariance principle for this conditioned forest by considering $k$ independent Galton-Watson trees whose offspring distribution is in the domain of attraction of any stable law conditioned on their total progeny to be equal to $n$. We prove that when $n$ and $k$ tend towards $+\infty$, under suitable rescaling, the associated coding random walk, the contour and height processes converge in law on the Skorokhod space respectively towards the "first passage bridge" of a stable L\'evy process with no negative jumps and its height process.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 14:13:51 GMT" } ]
2007-06-19T00:00:00
[ [ "Chaumont", "Loic", "", "LAREMA" ], [ "Millan", "Juan Carlos Pardo", "", "PMA" ] ]
0706.2606
Christian Schaffner
Serge Fehr, Christian Schaffner
Randomness Extraction via Delta-Biased Masking in the Presence of a Quantum Attacker
17 pages, v2: mainly editorial changes taking into account referee comments
null
null
null
quant-ph cs.CR
null
Randomness extraction is of fundamental importance for information-theoretic cryptography. It allows to transform a raw key about which an attacker has some limited knowledge into a fully secure random key, on which the attacker has essentially no information. Up to date, only very few randomness-extraction techniques are known to work against an attacker holding quantum information on the raw key. This is very much in contrast to the classical (non-quantum) setting, which is much better understood and for which a vast amount of different techniques are known and proven to work. We prove a new randomness-extraction technique, which is known to work in the classical setting, to be secure against a quantum attacker as well. Randomness extraction is done by XOR'ing a so-called delta-biased mask to the raw key. Our result allows to extend the classical applications of this extractor to the quantum setting. We discuss the following two applications. We show how to encrypt a long message with a short key, information-theoretically secure against a quantum attacker, provided that the attacker has enough quantum uncertainty on the message. This generalizes the concept of entropically-secure encryption to the case of a quantum attacker. As second application, we show how to do error-correction without leaking partial information to a quantum attacker. Such a technique is useful in settings where the raw key may contain errors, since standard error-correction techniques may provide the attacker with information on, say, a secret key that was used to obtain the raw key.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 14:16:02 GMT" }, { "version": "v2", "created": "Thu, 13 Dec 2007 09:19:49 GMT" } ]
2007-12-13T00:00:00
[ [ "Fehr", "Serge", "" ], [ "Schaffner", "Christian", "" ] ]
0706.2607
Mauro Sereno
M. Sereno (University of Zurich)
Kinematic effect in gravitational lensing by clusters of galaxies
6 pages; accepted for publication in MNRAS
null
10.1111/j.1365-2966.2007.12126.x
null
astro-ph
null
Gravitational lensing provides an efficient tool for the investigation of matter structures, independent of the dynamical or hydrostatic equilibrium properties of the deflecting system. However, it depends on the kinematic status. In fact, either a translational motion or a coherent rotation of the mass distribution can affect the lensing properties. Here, light deflection by galaxy clusters in motion is considered. Even if gravitational lensing mass measurements of galaxy clusters are regarded as very reliable estimates, the kinematic effect should be considered. A typical peculiar motion with respect to the Hubble flow brings about a systematic error < 0.3%, independent of the mass of the cluster. On the other hand, the effect of the spin increases with the total mass. For cluster masses ~ 10^{15}M_{sun}, the effect of the gravitomagnetic term is < 0.04% on strong lensing estimates and < 0.5% in the weak lensing analyses. The total kinematic effect on the mass estimate is then < 1%, which is negligible in current statistical studies. In the weak lensing regime, the rotation imprints a typical angular modulation in the tangential shear distortion. This would allow in principle a detection of the gravitomagnetic field and a direct measurement of the angular velocity of the cluster but the required background source densities are well beyond current tecnological capabilities.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 14:26:59 GMT" } ]
2009-11-13T00:00:00
[ [ "Sereno", "M.", "", "University of Zurich" ] ]
0706.2608
Kevin Knudson
Kevin P. Knudson
A refinement of multi-dimensional persistence
21 pages, 4 figures
null
null
null
math.AT
null
We study the multi-dimensional persistence of Carlsson and Zomorodian and obtain a finer classification based upon the higher tor-modules of a persistence module. We propose a variety structure on the set of isomorphism classes of these modules, and present several examples. We also provide a geometric interpretation for the higher tor-modules of homology modules of multi-filtered simplicial complexes.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 19:42:00 GMT" } ]
2007-06-19T00:00:00
[ [ "Knudson", "Kevin P.", "" ] ]
0706.2609
Chris White
C. D. White, R. S. Thorne
A Global Fit to Scattering Data with NLL BFKL Resummations
4 pages, 2 figures; Talk presented at the International Workshop on Deep-Inelastic Scattering and Related Subjects, Munich, Germany, April 16-20, 2007
null
null
NIKHEF/2007-014
hep-ph
null
We perform a global parton fit to DIS and related data, including next-to-leading logarithmic (NLL) BFKL resummations in both the massless and massive sectors. The resummed fit improves over a standard next-to-leading order (NLO) DGLAP fit, with a positive definite gluon at the input scale as opposed to the negative gluon seen at NLO. Furthermore, the predicted longitudinal structure function is free of perturbative instability at small x, and the reduced cross-section shows a turnover at high y (absent in the NLO fit) consistent with the HERA data.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 14:33:30 GMT" } ]
2007-06-19T00:00:00
[ [ "White", "C. D.", "" ], [ "Thorne", "R. S.", "" ] ]
0706.2610
Guang-Yu Guo
I. J. Wu and G. Y. Guo
Optical properties of SiC nanotubes: A systematic $\textit{ab initio}$ study
null
Phys. Rev. B 76, 035343 (2007)
10.1103/PhysRevB.76.035343
null
cond-mat.mtrl-sci
null
The band structure and optical dielectric function $\epsilon$ of single-walled zigzag [(3,0),(4,0),(5,0),(6,0),(8,0),(9,0),(12,0),(16,0),(20,0),(24,0)], armchair [(3,3),(4,4),(5,5),(8,8),(12,12),(15,15)], and chiral [(4,2),(6,2),(8,4),(10,4)] SiC-NTs as well as the single honeycomb SiC sheet have been calculated within DFT with the LDA. It is found that all the SiC nanotubes are semiconductors, except the ultrasmall (3,0) and (4,0) zigzag tubes which are metallic. Furthermore, the band gap of the zigzag SiC-NTs which is direct, may be reduced from that of the SiC sheet to zero by reducing the diameter ($D$), though the band gap for all the SiC nanotubes with a diameter larger than ~20 \AA$ $ is almost independent of diameter. For the electric field parallel to the tube axis ($E\parallel \hat{z}$), the $\epsilon''$ for all the SiC-NTs with a moderate diameter (say, $D$ $>$ 8 \AA$ $) in the low-energy region (0~6 eV) consists of a single distinct peak at ~3 eV. However, for the small diameter SiC nanotubes such as the (4,2),(4,4) SiC-NTs, the $\epsilon''$ spectrum does deviate markedly from this general behavior. In the high-energy region (from 6 eV upwards), the $\epsilon''$ for all the SiC-NTs exhibit a broad peak centered at ~7 eV. For the electric field perpendicular to the tube axis ($E\perp \hat{z}$), the $\epsilon''$ spectrum of all the SiC-NTs except the (4,4), (3,0) and (4,0) nanotubes, in the low energy region also consists of a pronounced peak at around 3 eV whilst in the high-energy region is roughly made up of a broad hump starting from 6 eV. The magnitude of the peaks is in general about half of the magnitude of the corresponding ones for $E\parallel \hat{z}$.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 14:30:13 GMT" } ]
2009-11-13T00:00:00
[ [ "Wu", "I. J.", "" ], [ "Guo", "G. Y.", "" ] ]
0706.2611
Carl E. Carlson
Zainul Abidin and Carl E. Carlson (William and Mary)
Rosenbluth Nonlinearity from Two-Photon Exchange
4 pages, 4 figures
Phys.Rev.D77:037301,2008
10.1103/PhysRevD.77.037301
WM-07-105
hep-ph
null
We calculate, using a generalized parton distribution based formalism, the nonlinearity of the Rosenbluth plots that arise from hard two-photon exchange corrections that are not included in the classic calculations of the radiative corrections to electron-proton elastic scattering.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 14:42:59 GMT" } ]
2008-11-26T00:00:00
[ [ "Abidin", "Zainul", "", "William and Mary" ], [ "Carlson", "Carl E.", "", "William and Mary" ] ]
0706.2612
Harold U. Baranger
M. Hentschel, D. Ullmo, and H. U. Baranger
Fermi Edge Singularities in the Mesoscopic Regime: II. Photo-absorption Spectra
16 pages
Phys. Rev. B 76, 245419 (2007)
10.1103/PhysRevB.76.245419
null
cond-mat.mes-hall
null
We study Fermi edge singularities in photo-absorption spectra of generic mesoscopic systems such as quantum dots or nanoparticles. We predict deviations from macroscopic-metallic behavior and propose experimental setups for the observation of these effects. The theory is based on the model of a localized, or rank one, perturbation caused by the (core) hole left behind after the photo-excitation of an electron into the conduction band. The photo-absorption spectra result from the competition between two many-body responses, Anderson's orthogonality catastrophe and the Mahan-Nozieres-DeDominicis contribution. Both mechanisms depend on the system size through the number of particles and, more importantly, fluctuations produced by the coherence characteristic of mesoscopic samples. The latter lead to a modification of the dipole matrix element and trigger one of our key results: a rounded K-edge typically found in metals will turn into a (slightly) peaked edge on average in the mesoscopic regime. We consider in detail the effect of the "bound state" produced by the core hole.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 17:46:52 GMT" } ]
2009-08-12T00:00:00
[ [ "Hentschel", "M.", "" ], [ "Ullmo", "D.", "" ], [ "Baranger", "H. U.", "" ] ]
0706.2613
Andreas Seifahrt
Andreas Seifahrt (1,2), Tristan Roell (2) and Ralph Neuhaeuser (2), ((1) European Southern Observatory, Garching, Germany, (2) Astrophysical Institute and University-Observatory Jena, Germany)
Probing micro-arcsec astrometry with NACO
To be published in the proceedings of the 2007 ESO Instrument Calibration Workshop
null
10.1007/978-3-540-76963-7_37
null
astro-ph
null
Relative astrometric measurements with a precision far better than 1 mas (milli-arcsec) are commonly regarded as the domain of interferometry. Pioneering work by Pravdo & Shaklan (1996), made in the optical, reached a precision of 150 micro-arcsec in direct imaging but is ultimately limited by atmospheric turbulence and differential chromatic refraction (DCR) effects. Neuhaeuser et al. (2006, 2007) demonstrated that AO assisted observations with NACO in a near-infrared narrow band filter allow measurements with a precision of ~50 muas (micro-arsec) on a 0.6 arcsec binary within one hour and are unaffected by DCR effects. This opens new possibilities for astrometric detections of extrasolar planets and the determination of their true masses. We discuss here how to improve the measurements and address the necessary calibrations.
[ { "version": "v1", "created": "Mon, 18 Jun 2007 14:46:38 GMT" } ]
2015-05-13T00:00:00
[ [ "Seifahrt", "Andreas", "" ], [ "Roell", "Tristan", "" ], [ "Neuhaeuser", "Ralph", "" ] ]