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0705.2098
Bikas K. Chakrabarti
Bikas K. Chakrabarti
Kolkata Restaurant Problem as a generalised El Farol Bar Problem
2 column RevTeX4, 4 pages, 3 eps figs; to be published in 'Econophysics of Markets and Business Networks', [Proc. Econophys-Kolkata III], Eds. A. Chatterjee, B. K. Chakrabarti, New Economic Windows Series, Springer, Milan, 2007, pp. 220-227
null
10.1007/978-88-470-0665-2_18
null
physics.soc-ph q-fin.ST
null
Generalisation of the El Farol bar problem to that of many bars here leads to the Kolkata restaurant problem, where the decision to go to any restaurant or not is much simpler (depending on the previous experience of course, as in the El Farol bar problem). This generalised problem can be exactly analysed in some limiting cases discussed here. The fluctuation in the restaurant service can be shown to have precisely an inverse cubic behavior, as widely seen in the stock market fluctuations.
[ { "version": "v1", "created": "Tue, 15 May 2007 11:41:54 GMT" } ]
2015-05-13T00:00:00
[ [ "Chakrabarti", "Bikas K.", "" ] ]
0705.2099
Yang Xing
Yang Xing
The General Definition of the Complex Monge-Amp\`ere Operator on Compact K\"ahler Manifolds
null
null
null
null
math.CV math.DG
null
We introduce a wide subclass ${\cal F}(X,\omega)$ of quasi-plurisubharmonic functions in a compact K\"ahler manifold, on which the complex Monge-Amp\`ere operator is well-defined and the convergence theorem is valid. We also prove that ${\cal F}(X,\omega)$ is a convex cone and includes all quasi-plurisubharmonic functions which are in the Cegrell class.
[ { "version": "v1", "created": "Tue, 15 May 2007 08:51:17 GMT" } ]
2007-05-23T00:00:00
[ [ "Xing", "Yang", "" ] ]
0705.2100
Tibor Toeroek
T. Toeroek, B. Kliem
Numerical simulations of fast and slow coronal mass ejections
4 pages, 3 figures, published in Astron. Nachr. 328, 743 (2007). Minor update to conform to published paper, with minor language improvements and citation updates included
null
10.1002/asna.200710795
null
astro-ph
null
Solar coronal mass ejections (CMEs) show a large variety in their kinematic properties. CMEs originating in active regions and accompanied by strong flares are usually faster and accelerated more impulsively than CMEs associated with filament eruptions outside active regions and weak flares. It has been proposed more than two decades ago that there are two separate types of CMEs, fast (impulsive) CMEs and slow (gradual) CMEs. However, this concept may not be valid, since the large data sets acquired in recent years do not show two distinct peaks in the CME velocity distribution and reveal that both fast and slow CMEs can be accompanied by both weak and strong flares. We present numerical simulations which confirm our earlier analytical result that a flux-rope CME model permits describing fast and slow CMEs in a unified manner. We consider a force-free coronal magnetic flux rope embedded in the potential field of model bipolar and quadrupolar active regions. The eruption is driven by the torus instability which occurs if the field overlying the flux rope decreases sufficiently rapidly with height. The acceleration profile depends on the steepness of this field decrease, corresponding to fast CMEs for rapid decrease, as is typical of active regions, and to slow CMEs for gentle decrease, as is typical of the quiet Sun. Complex (quadrupolar) active regions lead to the fastest CMEs.
[ { "version": "v1", "created": "Tue, 15 May 2007 09:22:03 GMT" }, { "version": "v2", "created": "Thu, 11 Oct 2007 09:41:07 GMT" } ]
2007-10-11T00:00:00
[ [ "Toeroek", "T.", "" ], [ "Kliem", "B.", "" ] ]
0705.2101
Henning Samtleben
Bernard de Wit, Henning Samtleben, Mario Trigiante
The maximal D=4 supergravities
41 pages, v2: minor corrections, published version
JHEP 0706:049,2007
10.1088/1126-6708/2007/06/049
ITP-UU-07/26, SPIN-07/17, ENSL-00146707
hep-th
null
All maximal supergravities in four space-time dimensions are presented. The ungauged Lagrangians can be encoded in an E_7(7)\Sp(56,R)/GL(28) matrix associated with the freedom of performing electric/magnetic duality transformations. The gauging is defined in terms of an embedding tensor which encodes the subgroup of E_7(7) that is realized as a local invariance. This embedding tensor may imply the presence of magnetic charges which require corresponding dual gauge fields. The latter can be incorporated by using a recently proposed formulation that involves tensor gauge fields in the adjoint representation of E_7(7). In this formulation the results take a universal form irrespective of the electric/magnetic duality basis. We present the general class of supersymmetric and gauge invariant Lagrangians and discuss a number of applications.
[ { "version": "v1", "created": "Tue, 15 May 2007 12:28:25 GMT" }, { "version": "v2", "created": "Fri, 22 Jun 2007 14:29:12 GMT" } ]
2009-11-13T00:00:00
[ [ "de Wit", "Bernard", "" ], [ "Samtleben", "Henning", "" ], [ "Trigiante", "Mario", "" ] ]
0705.2102
Nicolas Moeller
Nicolas Moeller
Closed Bosonic String Field Theory at Quintic Order II: Marginal Deformations and Effective Potential
28 pages
JHEP 0709:118,2007
10.1088/1126-6708/2007/09/118
SISSA 22/2007/EP
hep-th
null
We verify that the dilaton together with one exactly marginal field, form a moduli space of marginal deformations of closed bosonic string field theory to polynomial order five. We use the results of this successful check in order to find the best functional form of a fit of quintic amplitudes. We then use this fit in order to accurately compute the tachyon and dilaton effective potential in the limit of infinite level. We observe that to order four, the effective potential gives unexpectedly accurate results for the vacuum. We are thus led to conjecture that the effective potential, to a given order, is a good approximation to the whole potential including all interactions from the vertices up to this order from the untruncated string field. We then go on and compute the effective potential to order five. We analyze its vacuum structure and find that it has several saddle points, including the Yang-Zwiebach vacuum, but also a local minimum. We discuss the possible physical meanings of these vacua.
[ { "version": "v1", "created": "Tue, 15 May 2007 09:30:35 GMT" } ]
2009-04-17T00:00:00
[ [ "Moeller", "Nicolas", "" ] ]
0705.2103
Hiroshi Koibuchi
Hiroshi Koibuchi
Phase transition of compartmentalized surface models
10 pages with 16 figures
Euro. Phys. J. B57, 321-330 (2007)
10.1140/epjb/e2007-00170-y
ICT-Koi-2007-3
cond-mat.stat-mech cond-mat.soft
null
Two types of surface models have been investigated by Monte Carlo simulations on triangulated spheres with compartmentalized domains. Both models are found to undergo a first-order collapsing transition and a first-order surface fluctuation transition. The first model is a fluid surface one. The vertices can freely diffuse only inside the compartments, and they are prohibited from the free diffusion over the surface due to the domain boundaries. The second is a skeleton model. The surface shape of the skeleton model is maintained only by the domain boundaries, which are linear chains with rigid junctions. Therefore, we can conclude that the first-order transitions occur independent of whether the shape of surface is mechanically maintained by the skeleton (= the domain boundary) or by the surface itself.
[ { "version": "v1", "created": "Tue, 15 May 2007 09:23:55 GMT" } ]
2007-07-24T00:00:00
[ [ "Koibuchi", "Hiroshi", "" ] ]
0705.2104
Jun Ohkubo
Jun Ohkubo
Free energy of disordered urn models in the canonical ensemble
5 pages, 1 figure, to appear in J. Phys. Soc. Jpn
J. Phys. Soc. Jpn. 76, 095002 (2007).
10.1143/JPSJ.76.095002
null
cond-mat.dis-nn cond-mat.stat-mech
null
We calculate the free energy of the disordered urn model using the law of large numbers. It is revealed that the saddle point equation obtained by the usage of the law of large numbers is the same as that obtained by the replica method. Hence, we conclude that the replica symmetric solution is adequate for the disordered urn model. Furthermore, we point out the mathematical similarity of free energies between the urn models and the Random Field Ising Model; this similarity gives an evidence that the replica symmetric solution of the urn models is exact.
[ { "version": "v1", "created": "Tue, 15 May 2007 09:24:57 GMT" }, { "version": "v2", "created": "Thu, 2 Aug 2007 05:30:04 GMT" } ]
2009-11-13T00:00:00
[ [ "Ohkubo", "Jun", "" ] ]
0705.2105
Erik Volz
Erik Volz and Lauren Ancel Meyers
SIR epidemics in dynamic contact networks
20 pages, 4 figures. Submitted to Proc. Roy. Soc. B
null
null
null
q-bio.PE q-bio.QM
null
Contact patterns in populations fundamentally influence the spread of infectious diseases. Current mathematical methods for epidemiological forecasting on networks largely assume that contacts between individuals are fixed, at least for the duration of an outbreak. In reality, contact patterns may be quite fluid, with individuals frequently making and breaking social or sexual relationships. Here we develop a mathematical approach to predicting disease transmission on dynamic networks in which each individual has a characteristic behavior (typical contact number), but the identities of their contacts change in time. We show that dynamic contact patterns shape epidemiological dynamics in ways that cannot be adequately captured in static network models or mass-action models. Our new model interpolates smoothly between static network models and mass-action models using a mixing parameter, thereby providing a bridge between disparate classes of epidemiological models. Using epidemiological and sexual contact data from an Atlanta high school, we then demonstrate the utility of this method for forecasting and controlling sexually transmitted disease outbreaks.
[ { "version": "v1", "created": "Tue, 15 May 2007 09:40:40 GMT" } ]
2007-05-23T00:00:00
[ [ "Volz", "Erik", "" ], [ "Meyers", "Lauren Ancel", "" ] ]
0705.2106
Finn {\AA}rup Nielsen
Finn Aarup Nielsen
Scientific citations in Wikipedia
5 pages, 2 figures
First Monday, 12(8), 2007 August
null
null
cs.DL cs.IR
null
The Internet-based encyclopaedia Wikipedia has grown to become one of the most visited web-sites on the Internet. However, critics have questioned the quality of entries, and an empirical study has shown Wikipedia to contain errors in a 2005 sample of science entries. Biased coverage and lack of sources are among the "Wikipedia risks". The present work describes a simple assessment of these aspects by examining the outbound links from Wikipedia articles to articles in scientific journals with a comparison against journal statistics from Journal Citation Reports such as impact factors. The results show an increasing use of structured citation markup and good agreement with the citation pattern seen in the scientific literature though with a slight tendency to cite articles in high-impact journals such as Nature and Science. These results increase confidence in Wikipedia as an good information organizer for science in general.
[ { "version": "v1", "created": "Tue, 15 May 2007 09:42:30 GMT" } ]
2011-01-04T00:00:00
[ [ "Nielsen", "Finn Aarup", "" ] ]
0705.2107
Alain Pham Ngoc Dinh
Dang Duc Trong (UNS-HCMC), Alain Pham Ngoc Dinh (MAPMO), Phan Thanh Nam (UNS-HCMC), Truong Trung Tuyen (IU)
Determination of the body force of a two-dimensional isotropic elastic body
23 pages
Journal of Computational and Applied Mathematics 229 (2009) 192-207
null
null
math.AP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Let $\Omega$ represent a two$-$dimensional isotropic elastic body. We consider the problem of determining the body force $F$ whose form $\phi(t)(f_1(x),f_2(x))$ with $\phi$ be given inexactly. The problem is nonlinear and ill-posed. Using the Fourier transform, the methods of Tikhonov's regularization and truncated integration, we construct a regularized solution from the data given inexactly and derive the explicitly error estimate. Numerical part is given
[ { "version": "v1", "created": "Tue, 15 May 2007 10:07:40 GMT" }, { "version": "v2", "created": "Tue, 15 Jul 2008 10:00:33 GMT" } ]
2009-11-11T00:00:00
[ [ "Trong", "Dang Duc", "", "UNS-HCMC" ], [ "Dinh", "Alain Pham Ngoc", "", "MAPMO" ], [ "Nam", "Phan Thanh", "", "UNS-HCMC" ], [ "Tuyen", "Truong Trung", "", "IU" ] ]
0705.2108
Sergey Masalovich
S. Masalovich
Method to measure neutron beam polarization with 2x1 Neutron Spin Filter
13 pages, 3 figures, submitted to Nucl. Instrum. Methods A on 02 January 2007
Nucl.Instrum.Meth.A581:791-798,2007
10.1016/j.nima.2007.08.150
null
nucl-ex
null
A method to measure a beam polarization with the use of polarized 3He gas is discussed. It is shown that special design of the Neutron Spin Filter cell allows for a fast and accurate measurement. The accuracy of this method is analyzed.
[ { "version": "v1", "created": "Tue, 15 May 2007 10:10:30 GMT" } ]
2013-11-20T00:00:00
[ [ "Masalovich", "S.", "" ] ]
0705.2109
Szymon Plewik
Sung Soo Kim, Szymon Plewik
Discontinuity and Involutions on Countable Sets
The paper was published
Annales Mathematics Silesianae 17 (2003), 7 - 8
null
null
math.GM math.CO
null
For any infinite subset $X$ of the rationals and a subset $F \subseteq X$ which has no isolated points in $X$ we construct a function $f: X \to X$ such that $f(f(x))=x$ for each $x\in X$ and $F $ is the set of discontinuity points of $f$.
[ { "version": "v1", "created": "Tue, 15 May 2007 10:12:03 GMT" } ]
2007-05-23T00:00:00
[ [ "Kim", "Sung Soo", "" ], [ "Plewik", "Szymon", "" ] ]
0705.2110
Gilles Pages
Olivier Aj Bardou (GDF-RDD), Sandrine Bouthemy (GDF-RDD), Gilles Pag\`es (PMA)
Optimal quantization for the pricing of swing options
27p
Applied Mathematical Finance 16, 1-2 (2009) 183-217
10.1080/13504860802453218
null
q-fin.PR math.PR
null
In this paper, we investigate a numerical algorithm for the pricing of swing options, relying on the so-called optimal quantization method. The numerical procedure is described in details and numerous simulations are provided to assert its efficiency. In particular, we carry out a comparison with the Longstaff-Schwartz algorithm.
[ { "version": "v1", "created": "Tue, 15 May 2007 10:13:34 GMT" } ]
2013-04-03T00:00:00
[ [ "Bardou", "Olivier Aj", "", "GDF-RDD" ], [ "Bouthemy", "Sandrine", "", "GDF-RDD" ], [ "Pagès", "Gilles", "", "PMA" ] ]
0705.2111
V. Ryzhii
E.Vostrikova, A.Ivanov, I.Semenikhin, and V.Ryzhii
Electrical excitation of shock and soliton-like waves in two-dimensional electron channels
9 pages, 11 figures
null
10.1103/PhysRevB.76.035401
null
cond-mat.mes-hall
null
We study electrical excitation of nonlinear plasma waves in heterostructures with two-dimensional electron channels and with split gates, and the propagation of these waves using hydrodynamic equations for electron transport coupled with two-dimensional Poisson equation for self-consistent electric potential. The term related to electron collisions with impurities and phonons as well as the term associated with viscosity are included into the hydrodynamic equations. We demonstrate the formation of shock and soliton-like waves as a result of the evolution of strongly nonuniform initial electron density distribution. It is shown that the shock wave front and the shape of soliton-like pulses pronouncedly depend on the coefficient of viscosity, the thickness of the gate layer and the nonuniformity of the donor distribution along the channel. The electron collisions result in damping of the shock and soliton-like waves, while they do not markedly affect the thickness of the shock wave front.
[ { "version": "v1", "created": "Tue, 15 May 2007 10:26:23 GMT" } ]
2009-11-13T00:00:00
[ [ "Vostrikova", "E.", "" ], [ "Ivanov", "A.", "" ], [ "Semenikhin", "I.", "" ], [ "Ryzhii", "V.", "" ] ]
0705.2112
Simonetta Abenda
Simonetta Abenda
Algebraically closed real geodesics on n-dimensional ellipsoids are dense in the parameter space and related to hyperelliptic tangential coverings
v2: 37 pages, 6 figures v1: 25 pages, 6 figures
null
null
null
nlin.SI
null
The closedness condition for real geodesics on n-dimensional ellipsoids is in general transcendental in the parameters (semiaxes of the ellipsoid and constants of motion). We show that it is algebraic in the parameters if and only if both the real and the imaginary geodesics are closed and we characterize such double--periodicity condition via real hyperelliptic tangential coverings. We prove the density of algebraically closed geodesics on n-dimensional ellipsoids with respect to the natural topology in the (2n)-dimensional real parameter space. In particular, the approximating sequence of algebraic closed geodesics on the approximated ellipsoids may be chosen so to share the same values of the length and of the real period vector as the limiting closed geodesic on the limiting ellipsoid. Finally, for real doubly-periodic geodesics on triaxial ellipsoids, we show how to evaluate algebraically the period mapping and we present some explicit examples of families of algebraically closed geodesics.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:13:23 GMT" }, { "version": "v2", "created": "Tue, 3 Jun 2008 10:33:30 GMT" } ]
2008-06-03T00:00:00
[ [ "Abenda", "Simonetta", "" ] ]
0705.2113
Valentin V. Khoze
Steven Abel, Stefan Forste, Valentin V. Khoze
Scattering amplitudes in strongly coupled N=4 SYM from semiclassical strings in AdS
V3 extended version to appear in JHEP, new figures, clarifications and references added. 8 pages and 5 figs
JHEP0802:042,2008
10.1088/1126-6708/2008/02/042
IPPP/07/22, DCPT/07/44
hep-th hep-ph
null
Very recently in arXiv:0705.0303 Alday and Maldacena gave a string theory prescription for computing (all) planar amplitudes in N=4 supersymmetric gauge theory at strong coupling using the AdS/CFT correspondence. These amplitudes are determined by a classical string solution and contain a universal exponential factor involving the action of the classical string. On the gauge theory side, expressions for perturbative amplitudes at strong coupling were previously proposed only for specific helicities of external particles -- the maximally helicity violating or MHV amplitudes. These follow from the exponential ansatz of Bern, Dixon and Smirnov for MHV amplitudes in N=4 SYM. In this paper we examine the amplitudes dependence on helicities and particle-types of external states. We consider the prefactor of string amplitudes and give arguments suggesting that the prefactor at strong coupling should be the same as the Yang-Mills tree-level amplitude for the same process. This implies that scattering amplitudes in N=4 SYM simplify dramatically in the strong coupling limit. It follows from our proposal that in this limit all (MHV and non-MHV) n-point amplitudes are given by the (known) tree-level Yang-Mills result times the helicity-independent (and particle-type-independent) universal exponential.
[ { "version": "v1", "created": "Tue, 15 May 2007 12:06:39 GMT" }, { "version": "v2", "created": "Mon, 4 Jun 2007 15:14:17 GMT" }, { "version": "v3", "created": "Mon, 4 Feb 2008 19:47:13 GMT" } ]
2008-11-26T00:00:00
[ [ "Abel", "Steven", "" ], [ "Forste", "Stefan", "" ], [ "Khoze", "Valentin V.", "" ] ]
0705.2114
Harri Niemi
K.J. Eskola, H. Niemi and P.V. Ruuskanen
Elliptic flow from pQCD + saturation + hydro model
2 pages, 2 figures, to be presented at the workshop "Heavy Ion Collisions at the LHC: Last Call for Predictions" at CERN 29 May - 2 June
null
null
null
hep-ph
null
We have previously predicted multiplicities and transverse momentum spectra of hadrons for the most central LHC Pb+Pb collisions at $\sqrt{s_{NN}}=5.5$ TeV using initial state for hydrodynamic evolution from pQCD + final state saturation model. By considering binary collision and wounded nucleon profiles we extend these studies to non-central collisions, and predict the $p_{T}$ dependence of minimum bias $v_{2}$ for pions at the LHC. For protons we also show how the $p_{T}$ dependence of $v_2$ changes from RHIC to the LHC.
[ { "version": "v1", "created": "Tue, 15 May 2007 11:46:03 GMT" } ]
2007-05-23T00:00:00
[ [ "Eskola", "K. J.", "" ], [ "Niemi", "H.", "" ], [ "Ruuskanen", "P. V.", "" ] ]
0705.2115
Jan-Erik Solheim
J.-E. Solheim, G. Vauclair, A. S. Mukadam, R. Janulis, V. Dobrovolskas
Abell 43: Longest period Planetary Nebula Nucleus variable
5 pages, 5 figures, to be published in Astronomy and Astrophysics
null
10.1051/0004-6361:20077364
null
astro-ph
null
Based on 24h high speed photometry of the hybrid PG 1159 star Abell 43, we have detected 6 sighificant pulsations with periods between 2380 s and 6075 s. A short (4h) run on the almost spectroscopic twin NGC 7094 central star resulted in detection of 3 low amplitude pulsations with periods between 2000 s and 5000 s. The results are close to predictions for g-mode pulsations driven by the kappa-mechanism induced by the partial ionization of carbon and oxygen.
[ { "version": "v1", "created": "Tue, 15 May 2007 10:56:53 GMT" } ]
2009-11-13T00:00:00
[ [ "Solheim", "J. -E.", "" ], [ "Vauclair", "G.", "" ], [ "Mukadam", "A. S.", "" ], [ "Janulis", "R.", "" ], [ "Dobrovolskas", "V.", "" ] ]
0705.2116
Hassan Chamati
H Chamati and S Romano
First order phase transitions in classical lattice gas spin models
9 pages, 12 figures
Phys. Rev. B 75, 184413 (2007) (9 pages)
10.1103/PhysRevB.75.184413
null
cond-mat.stat-mech cond-mat.dis-nn
null
The present paper considers some classical ferromagnetic lattice--gas models, consisting of particles that carry $n$--component spins ($n=2,3$) and associated with a $D$--dimensional lattice ($D=2,3$); each site can host one particle at most, thus implicitly allowing for hard--core repulsion; the pair interaction, restricted to nearest neighbors, is ferromagnetic, and site occupation is also controlled by the chemical potential $\mu$. The models had previously been investigated by Mean Field and Two--Site Cluster treatments (when D=3), as well as Grand--Canonical Monte Carlo simulation in the case $\mu=0$, for both D=2 and D=3; the obtained results showed the same kind of critical behaviour as the one known for their saturated lattice counterparts, corresponding to one particle per site. Here we addressed by Grand--Canonical Monte Carlo simulation the case where the chemical potential is negative and sufficiently large in magnitude; the value $\mu=-D/2$ was chosen for each of the four previously investigated counterparts, together with $\mu=-3D/4$ in an additional instance. We mostly found evidence of first order transitions, both for D=2 and D=3, and quantitatively characterized their behaviour. Comparisons are also made with recent experimental results.
[ { "version": "v1", "created": "Tue, 15 May 2007 10:59:48 GMT" } ]
2007-05-23T00:00:00
[ [ "Chamati", "H", "" ], [ "Romano", "S", "" ] ]
0705.2117
Hassan Chagani
R. Bisset, M. J. Carson, H. Chagani, D. B. Cline, E. J. Daw, T. Ferbel, J. Gao, Y. S. Gao, V. A. Kudryavtsev, P. K. Lightfoot, P. Majewski, J. Maxin, J. Miller, W. C. Ooi, M. Robinson, G. Salinas, U. Schroeder, J. Seifert, F. Sergiampietri, W. Skulski, P. F. Smith, N. J. C. Spooner, J. Toke, H. Wang, J. T. White, F. Wolfs, X. Yang
R & D for Future Zeplin
to appear in Proc. 7th UCLA Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe, 22-24 February, Marina del Rey, USA; Nucl. Phys. B Proc. Suppl., in press; 4 pages, 3 figues
Nucl.Phys.Proc.Suppl.173:164-167,2007
10.1016/j.nuclphysbps.2007.08.154
null
astro-ph
null
We propose a new concept for a very low background multi-ton liquid xenon Dark Matter experiment. The detector consists of two concentric spheres and a charge readout device in the centre. Xenon between the two spheres forms a self-shield and veto device. The inner surface of the central sphere is coated with CsI to form an internal photocathode with minimum of 2\pi coverage for any event in the active volume. Photoelectrons from the CsI photocathode drift toward the charge readout micro-structure in the centre of the detector. Both scintillation and ionisation are measured simultaneously for background rejection and 3-D event mapping. In addition to external shielding, the low background is achieved by eliminating PMTs and by using low radioactivity pure materials throughout the detector. We present detailed calculations of the charge readout system and design details. The detector is expected to probe the full SUSY parameter space.
[ { "version": "v1", "created": "Tue, 15 May 2007 11:02:19 GMT" } ]
2009-06-23T00:00:00
[ [ "Bisset", "R.", "" ], [ "Carson", "M. J.", "" ], [ "Chagani", "H.", "" ], [ "Cline", "D. B.", "" ], [ "Daw", "E. J.", "" ], [ "Ferbel", "T.", "" ], [ "Gao", "J.", "" ], [ "Gao", "Y. S.", "" ], [ "Kudryavtsev", "V. A.", "" ], [ "Lightfoot", "P. K.", "" ], [ "Majewski", "P.", "" ], [ "Maxin", "J.", "" ], [ "Miller", "J.", "" ], [ "Ooi", "W. C.", "" ], [ "Robinson", "M.", "" ], [ "Salinas", "G.", "" ], [ "Schroeder", "U.", "" ], [ "Seifert", "J.", "" ], [ "Sergiampietri", "F.", "" ], [ "Skulski", "W.", "" ], [ "Smith", "P. F.", "" ], [ "Spooner", "N. J. C.", "" ], [ "Toke", "J.", "" ], [ "Wang", "H.", "" ], [ "White", "J. T.", "" ], [ "Wolfs", "F.", "" ], [ "Yang", "X.", "" ] ]
0705.2118
Todor Gramchev
Todor Gramchev and Andrea Loi
TYZ expansion for the Kepler manifold
27 pages
null
null
null
math.DG math.CV
null
The main goal of the paper is to address the issue of the existence of Kempf's distortion function and the Tian-Yau-Zelditch (TYZ) asymptotic expansion for the Kepler manifold - an important example of non compact manfold. Motivated by the recent results for compact manifolds we construct Kempf's distortion function and derive a precise TYZ asymptotic expansion for the Kepler manifold. We get an exact formula: finite asymptotic expansion of $n-1$ terms and exponentially small error terms uniformly with respect to the discrete quantization parameter $m\to \infty $ and $\rho \to \infty$, $\rho$ being the polar radius in $\C^n$. Moreover, the coefficents are calculated explicitly and they turned out to be homogeneous functions with respect to the polar radius in the Kepler manifold. We also prove and derive an asymptotic expansion of the obtstruction term with the coefficients being defined by geometrical quantities. We show that our estimates are sharp by analyzing the nonharmonic behaviour of $T_m$ and the error term of the approximation of the Fubini--Study metric by $m\omega$ for $m\to +\infty$. The arguments of the proofs combine geometrical methods, quantization tools and functional analytic techniques for investigating asymptotic expansions in the framework of analytic-Gevrey spaces.
[ { "version": "v1", "created": "Tue, 15 May 2007 11:07:17 GMT" } ]
2007-05-23T00:00:00
[ [ "Gramchev", "Todor", "" ], [ "Loi", "Andrea", "" ] ]
0705.2119
Michel Calame
L. Bernard, M. Calame, S. J. van der Molen, J. Liao and C. Schoenenberger
Controlled formation of metallic nanowires via Au nanoparticle ac trapping
Nanotechnology 18, 235202 (2007)
null
10.1088/0957-4484/18/23/235202
null
cond-mat.mes-hall
null
Applying ac voltages, we trapped gold nanoparticles between microfabricated electrodes under well-defined conditions. We demonstrate that the nanoparticles can be controllably fused together to form homogeneous gold nanowires with pre-defined diameters and conductance values. Whereas electromigration is known to form a gap when a dc voltage is applied, this ac technique achieves the opposite, thereby completing the toolkit for the fabrication of nanoscale junctions.
[ { "version": "v1", "created": "Tue, 15 May 2007 14:01:11 GMT" } ]
2007-05-23T00:00:00
[ [ "Bernard", "L.", "" ], [ "Calame", "M.", "" ], [ "van der Molen", "S. J.", "" ], [ "Liao", "J.", "" ], [ "Schoenenberger", "C.", "" ] ]
0705.2120
Christopher Allan Watson
C.A. Watson, D. Steeghs, V.S. Dhillon, T. Shahbaz
Imaging the cool stars in the interacting binaries AE Aqr, BV Cen and V426 Oph
4 pages, 3 figures. Conference proceedings for the N+N+N Workshop, "From our star to far stars: Variation and Variability". Accepted for publication in Astronomische Nachrichten
null
10.1002/asna.200710800
null
astro-ph
null
It is well known that magnetic activity in late-type stars increases with increasing rotation rate. Using inversion techniques akin to medical imaging, the rotationally broadened profiles from such stars can be used to reconstruct `Doppler images' of the distribution of cool, dark starspots on their stellar surfaces. Interacting binaries, however, contain some of the most rapidly rotating late-type stars known and thus provide important tests of stellar dynamo models. Furthermore, magnetic activity is thought to play a key role in their evolution, behaviour and accretion dynamics. Despite this, we know comparatively little about the magnetic activity and its influence on such binaries. In this review we summarise the concepts behind indirect imaging of these systems, and present movies of the starspot distributions on the cool stars in some interacting binaries. We conclude with a look at the future opportunities that such studies may provide.
[ { "version": "v1", "created": "Tue, 15 May 2007 11:10:15 GMT" } ]
2009-11-13T00:00:00
[ [ "Watson", "C. A.", "" ], [ "Steeghs", "D.", "" ], [ "Dhillon", "V. S.", "" ], [ "Shahbaz", "T.", "" ] ]
0705.2121
Iwo Bialynicki-Birula
Iwo Bialynicki-Birula and Tomasz Sowinski
Quantum Electrodynamics of qubits
23 pages, 6 figures
Physical Review A 76, 06106 (2007)
10.1103/PhysRevA.76.062106
null
quant-ph
null
Systematic description of a spin one-half system endowed with magnetic moment or any other two-level system (qubit) interacting with the quantized electromagnetic field is developed. This description exploits a close analogy between a two-level system and the Dirac electron that comes to light when the two-level system is described within the formalism of second quantization in terms of fermionic creation and annihilation operators. The analogy enables one to introduce all the powerful tools of relativistic QED (albeit in a greatly simplified form). The Feynman diagrams and the propagators turn out to be very useful. In particular, the QED concept of the vacuum polarization finds its close counterpart in the photon scattering off a two level-system leading via the linear response theory to the general formulas for the atomic polarizability and the dynamic single spin susceptibility. To illustrate the usefulness of these methods, we calculate the polarizability and susceptibility up to the fourth order of perturbation theory. These {\em ab initio} calculations resolve some ambiguities concerning the sign prescription and the optical damping that arise in the phenomenological treatment. We also show that the methods used to study two-level systems (qubits) can be extended to many-level systems (qudits). As an example, we describe the interaction with the quantized electromagnetic field of an atom with four relevant states: one S state and three degenerate P states.
[ { "version": "v1", "created": "Tue, 15 May 2007 11:24:13 GMT" }, { "version": "v2", "created": "Wed, 12 Dec 2007 11:30:17 GMT" } ]
2009-11-13T00:00:00
[ [ "Bialynicki-Birula", "Iwo", "" ], [ "Sowinski", "Tomasz", "" ] ]
0705.2122
Robert Tautz
R. C. Tautz, I. Lerche
Isolated unstable Weibel modes in unmagnetized plasmas with tunable asymmetry
Comments: references added
J.Phys.A40:F677-F684,2007
10.1088/1751-8113/40/29/F04
null
astro-ph
null
In this letter, an initially unmagnetized pair plasma with asymmetric velocity distributions is investigated where any unstable Weibel mode must be isolated, with discrete values for the growth rates and the unstable wavenumbers. For both a non-relativistic distribution with thermal spread and a high-relativistic two-stream distribution it is shown that isolated modes are excited and that, as the asymmetry tends to zero, the growth rate remains finite, as long as the distribution function is not precisely symmetric.
[ { "version": "v1", "created": "Tue, 15 May 2007 11:30:22 GMT" }, { "version": "v2", "created": "Tue, 22 May 2007 13:12:16 GMT" }, { "version": "v3", "created": "Tue, 3 Jul 2007 14:12:47 GMT" } ]
2013-06-25T00:00:00
[ [ "Tautz", "R. C.", "" ], [ "Lerche", "I.", "" ] ]
0705.2123
Hagai B. Perets
Hagai B. Perets, Tal Alexander
Massive perturbers and the efficient merger of binary massive black holes
14 pages, 4 figures, 3 tables. More detailed explanations and changes in structure. Section on hypervelocity stars moved to another paper (in preparation). Results and conclusions unchanged. Accepted to ApJ
null
10.1086/527525
null
astro-ph
null
We show that dynamical relaxation in the aftermath of a galactic merger and the ensuing formation and decay of a binary massive black hole (MBH), are dominated by massive perturbers (MPs) such as giant molecular clouds or clusters. MPs accelerate relaxation by orders of magnitude relative to 2-body stellar relaxation alone, and efficiently scatter stars into the binary MBH's orbit. The 3-body star-binary MBH interactions shrink the binary MBH to the point where energy losses from the emission of gravitational waves (GW) lead to rapid coalescence. We model this process based on observed and simulated MP distributions and take into account the decreased efficiency of the star-binary MBH interaction due to acceleration in the galactic potential. We show that mergers of gas-rich galactic nuclei lead to binary MBH coalescence well within the Hubble time. Moreover, lower-mass binary MBHs (<10^8 Msun) require only a few percent of the typical gas mass in a post-merger nucleus to coalesce in a Hubble time. The fate of a binary MBH in a gas poor galactic merger is less certain, although massive stellar structures (e.g. clusters, stellar rings) could likewise lead to efficient coalescence. These coalescence events are observable by their strong GW emission. MPs thus increase the cosmic rate of such GW events, lead to a higher mass deficit in the merged galactic core and suppress the formation of triple MBH systems and the resulting ejection of MBHs into intergalactic space.
[ { "version": "v1", "created": "Tue, 15 May 2007 12:39:31 GMT" }, { "version": "v2", "created": "Tue, 4 Dec 2007 06:07:16 GMT" } ]
2009-11-13T00:00:00
[ [ "Perets", "Hagai B.", "" ], [ "Alexander", "Tal", "" ] ]
0705.2124
Fabio Zuddas
Andrea Loi and Fabio Zuddas
Extremal metrics on Hartogs domains
14 pages
null
null
null
math.DG math.CV
null
An $n$-dimensional Hartogs domain $D_F$ with strongly pseudoconvex boundary can be equipped with a natural \K metric $g_F$. In this paper we prove that if $g_F$ is an extremal \K metric then $(D_F, g_F)$ is biholomorphically isometric to the $n$-dimensional complex hyperbolic space.
[ { "version": "v1", "created": "Tue, 15 May 2007 11:36:40 GMT" } ]
2007-05-23T00:00:00
[ [ "Loi", "Andrea", "" ], [ "Zuddas", "Fabio", "" ] ]
0705.2125
Ching-Lueh Chang
Ching-Lueh Chang, Yuh-Dauh Lyuu
Parallelized approximation algorithms for minimum routing cost spanning trees
null
null
null
null
cs.DS cs.CC
null
We parallelize several previously proposed algorithms for the minimum routing cost spanning tree problem and some related problems.
[ { "version": "v1", "created": "Tue, 15 May 2007 17:48:42 GMT" }, { "version": "v2", "created": "Wed, 4 Jul 2007 20:10:22 GMT" } ]
2007-07-04T00:00:00
[ [ "Chang", "Ching-Lueh", "" ], [ "Lyuu", "Yuh-Dauh", "" ] ]
0705.2126
Francois De Ferriere
Francois De Ferriere
Improvements to the Psi-SSA representation
null
Published in proceedings for the workshop "Software and Compilers for Embedded Systems (SCOPES) 2007" (20/04/2007)
null
null
cs.PL
null
Modern compiler implementations use the Static Single Assignment representation as a way to efficiently implement optimizing algorithms. However this representation is not well adapted to architectures with a predicated instruction set. The Psi-SSA representation extends the SSA representation such that standard SSA algorithms can be easily adapted to an architecture with a fully predicated instruction set. A new pseudo operation, the Psi operation, is introduced to merge several conditional definitions into a unique definition.
[ { "version": "v1", "created": "Tue, 15 May 2007 12:06:32 GMT" } ]
2007-05-23T00:00:00
[ [ "De Ferriere", "Francois", "" ] ]
0705.2127
Ali Ayad
Ali Ayad (IRMAR)
On the complexity of solving ordinary differential equations in terms of Puiseux series
null
null
null
2007-30
math.GM
null
We prove that the binary complexity of solving ordinary polynomial differential equations in terms of Puiseux series is single exponential in the number of terms in the series. Such a bound was given by Grigoriev [10] for Riccatti differential polynomials associated to ordinary linear differential operators. In this paper, we get the same bound for arbitrary differential polynomials. The algorithm is based on a differential version of the Newton-Puiseux procedure for algebraic equations.
[ { "version": "v1", "created": "Tue, 15 May 2007 12:06:58 GMT" } ]
2007-05-23T00:00:00
[ [ "Ayad", "Ali", "", "IRMAR" ] ]
0705.2128
Jean Picard
Jean Picard
A tree approach to $p$-variation and to integration
null
Annals of Probability 36, 6 (2008) 2235-2279
10.1214/07-AOP388
null
math.PR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider a real-valued path; it is possible to associate a tree to this path, and we explore the relations between the tree, the properties of $p$-variation of the path, and integration with respect to the path. In particular, the fractal dimension of the tree is estimated from the variations of the path, and Young integrals with respect to the path, as well as integrals from the rough paths theory, are written as integrals on the tree. Examples include some stochastic paths such as martingales, L\'evy processes and fractional Brownian motions (for which an estimator of the Hurst parameter is given).
[ { "version": "v1", "created": "Tue, 15 May 2007 12:08:23 GMT" }, { "version": "v2", "created": "Thu, 22 Jan 2009 10:59:12 GMT" } ]
2009-01-22T00:00:00
[ [ "Picard", "Jean", "" ] ]
0705.2129
Evgeny Kurbatov
E.P. Kurbatov
An efficient method for calculation of cooling in Lagrange computational gas dynamics
submitted to JCompPhys, 5 pages, 1 figure
null
null
null
astro-ph
null
A new method for computation of gas cooling for Lagrange approach is suggested. The method is based on precalculation of cooling law for known cooling function. Unlike implicit methods, this method is very efficient, it is an one-step method which is even more accurate than implicit methods of the same order.
[ { "version": "v1", "created": "Tue, 15 May 2007 12:10:39 GMT" } ]
2007-05-23T00:00:00
[ [ "Kurbatov", "E. P.", "" ] ]
0705.2130
Alain Corfdir
Alain Corfdir (ENPC-Cermes), Guy Bonnet (LaM)
Validity conditions of the direct boundary integral equation for exterior problems of plane elasticity
null
Comptes Rendus Mecanique 335 (2007) 219-224
10.1016/j.crme.2007.03.010
null
physics.class-ph
null
Writing the boundary integral equation for an exterior problem of elasticity is subordinate so far to hypotheses on the asymptotical behaviour at infinity of solutions. The sufficient conditions met in the literature are too restrictive and do not notably cover the case when the loading has a non zero resultant force. This difficulty can be removed by considering the problem in displacements relatively to one point located at a finite distance from the loading. Finally, this auxiliary problem allows widening the conditions of validity of the usual formulation of the direct integral method.
[ { "version": "v1", "created": "Tue, 15 May 2007 12:13:35 GMT" } ]
2009-11-13T00:00:00
[ [ "Corfdir", "Alain", "", "ENPC-Cermes" ], [ "Bonnet", "Guy", "", "LaM" ] ]
0705.2131
Winfried Zimdahl
Winfried Zimdahl
Dark Energy: A Unifying View
9 pages, selected for "Honorable Mention" by the Gravity Research Foundation
Int.J.Mod.Phys.D17:651-658,2008
10.1142/S0218271808012395
null
gr-qc astro-ph hep-th
null
Different models of the cosmic substratum which pretend to describe the present stage of accelerated expansion of the Universe like the $\Lambda$CDM model or a Chaplygin gas, can be seen as special realizations of a holographic dark energy cosmology if the option of an interaction between pressurless dark matter and dark energy is taken seriously. The corresponding interaction strength parameter plays the role of a cosmological constant. Differences occur at the perturbative level. In particular, the pressure perturbations are intrinsically non-adiabatic.
[ { "version": "v1", "created": "Tue, 15 May 2007 12:18:10 GMT" } ]
2008-11-26T00:00:00
[ [ "Zimdahl", "Winfried", "" ] ]
0705.2132
Yair Goldfarb
Yair Goldfarb, Ilan Degani and David, J. Tannor
Semiclassical approximation with zero velocity trajectories
16 pages, 7 figures
null
10.1016/j.chemphys.2007.05.014
null
quant-ph
null
We present a new semiclassical method that yields an approximation to the quantum mechanical wavefunction at a fixed, predetermined position. In the approach, a hierarchy of ODEs are solved along a trajectory with zero velocity. The new approximation is local, both literally and from a quantum mechanical point of view, in the sense that neighboring trajectories do not communicate with each other. The approach is readily extended to imaginary time propagation and is particularly useful for the calculation of quantities where only local information is required. We present two applications: the calculation of tunneling probabilities and the calculation of low energy eigenvalues. In both applications we obtain excellent agrement with the exact quantum mechanics, with a single trajectory propagation.
[ { "version": "v1", "created": "Tue, 15 May 2007 12:19:11 GMT" } ]
2009-11-13T00:00:00
[ [ "Goldfarb", "Yair", "" ], [ "Degani", "Ilan", "" ], [ "David", "", "" ], [ "Tannor", "J.", "" ] ]
0705.2133
Ying-Qiu Gu
Ying-Qiu Gu
The Exact Solutions to the Gravitational Contraction in Comoving Coordinate System
9 pages, 1 figure
null
null
null
gr-qc astro-ph.SR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The gravitational collapse of a star is a warmly discussed but still puzzling problem, which not only involves the dynamics of the gases, but also the subtle coordinate transformation. In this letter, we give some more detailed investigation on this problem, and reach the results: (I). The comoving coordinate system for the stellar system is only compatible with the zero-pressure free falling particles. (II). For the free falling dust, there are three kind of solutions respectively corresponding to the oscillating, the critical and the open trajectories. The solution of Oppenheimer and Snyder is the critical case. (III). All solutions are exactly derived. There is a new kind singularity in the solution, but its origin is unclear.
[ { "version": "v1", "created": "Tue, 15 May 2007 12:35:47 GMT" }, { "version": "v2", "created": "Sat, 25 Apr 2009 03:08:13 GMT" } ]
2009-04-30T00:00:00
[ [ "Gu", "Ying-Qiu", "" ] ]
0705.2134
Yong-Yeon Keum
Kiyotomo Ichiki and Yong-Yeon Keum
Primordial Neutrinos, Cosmological Perturbations in Interacting Dark-Energy Model: CMB and LSS
26 pages Revtex, 11 figures, Add new contents and references
JCAP 0806:005,2008
10.1088/1475-7516/2008/06/005
NTU-Astro-2007-01
astro-ph gr-qc hep-ph
null
We present cosmological perturbation theory in neutrinos probe interacting dark-energy models, and calculate cosmic microwave background anisotropies and matter power spectrum. In these models, the evolution of the mass of neutrinos is determined by the quintessence scalar field, which is responsible for the cosmic acceleration today. We consider several types of scalar field potentials and put constraints on the coupling parameter between neutrinos and dark energy. Assuming the flatness of the universe, the constraint we can derive from the current observation is $\sum m_{\nu} < 0.87 eV$ at the 95 % confidence level for the sum over three species of neutrinos. We also discuss on the stability issue of the our model and on the impact of the scattering term in Boltzmann equation from the mass-varying neutrinos.
[ { "version": "v1", "created": "Tue, 15 May 2007 12:40:50 GMT" }, { "version": "v2", "created": "Thu, 13 Mar 2008 19:05:18 GMT" } ]
2009-06-23T00:00:00
[ [ "Ichiki", "Kiyotomo", "" ], [ "Keum", "Yong-Yeon", "" ] ]
0705.2135
Martin Dressel
Martin Dressel
Ordering phenomena in quasi one-dimensional organic conductors
Review article Naturwissenschaften 2007
Naturwissenschaften 94, 527- 541 (2007)
10.1007/s00114-007-0227-1
null
cond-mat.str-el
null
Low-dimensional organic conductors could establish themselves as model systems for the investigation of the physics in reduced dimensions. In the metallic state of a one-dimensional solid, Fermi-liquid theory breaks down and spin and charge degrees of freedom become separated. But the metallic phase is not stable in one dimension: as the temperature is reduced, the electronic charge and spin tend to arrange themselves in an ordered fashion due to strong correlations. The competition of the different interactions is responsible for which broken-symmetry ground state is eventually realized in a specific compound and which drives the system towards an insulating state. Here we review the various ordering phenomena and how they can be identified by optic and magnetic measurements. While the final results might look very similar in the case of a charge density wave and a charge-ordered metal, for instance, the physical cause is completely different. When density waves form, a gap opens in the density of states at the Fermi energy due to nesting of the one-dimension Fermi surface sheets. When a one-dimensional metal becomes a charge-ordered Mott insulator, on the other hand, the short-range Coulomb repulsion localizes the charge on the lattice sites and even causes certain charge patterns. We try to point out the similarities and conceptional differences of these phenomena and give an example for each of them. Particular emphasis will be put on collective phenomena which are inherently present as soon as ordering breaks the symmetry of the system.
[ { "version": "v1", "created": "Mon, 14 May 2007 22:08:29 GMT" } ]
2007-11-08T00:00:00
[ [ "Dressel", "Martin", "" ] ]
0705.2136
C\'edric Foellmi
C. Foellmi, T.H. Dall, J. Pritchard, G. Lo Curto, C. Allende Prieto, H. Bruntt, P.J. Amado, T. Arentoft, M. Baes, E. Depagne, M. Fernandez, V.D. Ivanov, L. Koesterke, L. Monaco, K O'Brien, L.M. Sarro, I. Saviane, J. Scharwaechter, L. Schmidtobreick, O. Schuetz, A. Seifahrt, F. Selman, M. Stefanon, M. Sterzik
The Variable Star One-shot Project, and its little child: Wikimbad
4 pages, 3 figures, to appear in the proceedings of the workshop help at ESA, in March 2007, entitled "Astronomical Spectroscopy and Virtual Observatory"
null
null
null
astro-ph
null
The Variable Star One-shot Project (VSOP) aimed at providing to the world-wide stellar community the necessary one-shot spectrum of unstudied variable stars, too often classified as such by an analysis of photometric data only. The VSOP has established an new kind of observational model, where all steps from observations to spectral analysis, are automatized (or are underway to be fully automatized). The project is centralized on a collaborative wiki website. The VSOP operational model is very successful, data is continously flowing and being analyszed, and VSOP is now a worldwide open collaboration of people with very different and complementary skills and expertise. The idea of a central wiki website has been extended by one of us to propose a new service to the whole astronomical community, called Wikimbad. Wikimbad is an open wiki website aimed at collecting, organizing and making publicly available all kind of reduced and published astronomical data. Its strengths and a comparison with the Virtual Observatory are discussed. See: http://vsop.sc.eso.org and http://wikimbad.org
[ { "version": "v1", "created": "Tue, 15 May 2007 13:16:49 GMT" } ]
2007-05-25T00:00:00
[ [ "Foellmi", "C.", "" ], [ "Dall", "T. H.", "" ], [ "Pritchard", "J.", "" ], [ "Curto", "G. Lo", "" ], [ "Prieto", "C. Allende", "" ], [ "Bruntt", "H.", "" ], [ "Amado", "P. J.", "" ], [ "Arentoft", "T.", "" ], [ "Baes", "M.", "" ], [ "Depagne", "E.", "" ], [ "Fernandez", "M.", "" ], [ "Ivanov", "V. D.", "" ], [ "Koesterke", "L.", "" ], [ "Monaco", "L.", "" ], [ "O'Brien", "K", "" ], [ "Sarro", "L. M.", "" ], [ "Saviane", "I.", "" ], [ "Scharwaechter", "J.", "" ], [ "Schmidtobreick", "L.", "" ], [ "Schuetz", "O.", "" ], [ "Seifahrt", "A.", "" ], [ "Selman", "F.", "" ], [ "Stefanon", "M.", "" ], [ "Sterzik", "M.", "" ] ]
0705.2137
Igor Pesek
Igor Pesek, Janez \v{Z}erovnik
Best insertion algorithm for resource-constrained project scheduling problem
8 pages, submitted to conference KOI 2006
null
null
null
cs.DM
null
This paper considers heuristics for well known resource-constrained project scheduling problem (RCPSP). First a feasible schedule is constructed using randomized best insertion algorithm. The construction is followed by a local search where a new solution is generated as follows: first we randomly delete m activities from the list, which are then reinserted in the list in consecutive order. At the end of run, the schedule with the minimum makespan is selected. Experimental work shows very good results on standard test instances found in PSPLIB
[ { "version": "v1", "created": "Tue, 15 May 2007 13:18:47 GMT" } ]
2007-05-23T00:00:00
[ [ "Pesek", "Igor", "" ], [ "Žerovnik", "Janez", "" ] ]
0705.2138
P\'eter Klagyivik
P. Klagyivik, L. Szabados
Study of the effect of metallicity on the amplitudes of Cepheids
Accepted for publication in Astronomische Nachrichten (Astronomical Notes). 4 pages, 5 figures
null
10.1002/asna.200710802
null
astro-ph
null
Results concerning the dependence of photometric and radial velocity amplitudes on metallicity are presented based on about 200 Galactic classical Cepheids pulsating in the fundamental mode. The Galactic distribution of the [Fe/H] value of Cepheids is also studied. We show that the photometric amplitude ratio $A_\mathrm{I}/A_\mathrm{V}$ is independent of metallicity. The observed dependence of this ratio on the pulsation period does not correspond to the theoretical predictions.
[ { "version": "v1", "created": "Tue, 15 May 2007 13:05:16 GMT" } ]
2009-11-13T00:00:00
[ [ "Klagyivik", "P.", "" ], [ "Szabados", "L.", "" ] ]
0705.2139
S. G. Rajeev
S. G. Rajeev
Fuzzy Fluid Mechanics in Three Dimensions
Additional references
Int.J.Mod.Phys.A23:1019-1028,2008
10.1142/S0217751X08038615
null
math-ph cond-mat.stat-mech gr-qc hep-th math.AP math.MP math.QA nlin.CD physics.flu-dyn
null
We introduce a rotation invariant short distance cut-off in the theory of an ideal fluid in three space dimensions, by requiring momenta to take values in a sphere. This leads to an algebra of functions in position space is non-commutative. Nevertheless it is possible to find appropriate analogues of the Euler equations of an ideal fluid. The system still has a hamiltonian structure. It is hoped that this will be useful in the study of possible singularities in the evolution of Euler (or Navier-Stokes) equations in three dimensions.
[ { "version": "v1", "created": "Tue, 15 May 2007 19:12:50 GMT" }, { "version": "v2", "created": "Wed, 30 May 2007 03:42:11 GMT" } ]
2016-09-08T00:00:00
[ [ "Rajeev", "S. G.", "" ] ]
0705.2140
Vasilis Niarchos
Dan Israel and Vasilis Niarchos
Tree-Level Stability Without Spacetime Fermions: Novel Examples in String Theory
harvmac, 29 pages; v2 minor changes, version to appear in JHEP
JHEP 0707:065,2007
10.1088/1126-6708/2007/07/065
null
hep-th
null
Is perturbative stability intimately tied with the existence of spacetime fermions in string theory in more than two dimensions? Type 0'B string theory in ten-dimensional flat space is a rare example of a non-tachyonic, non-supersymmetric string theory with a purely bosonic closed string spectrum. However, all known type 0' constructions exhibit massless NSNS tadpoles signaling the fact that we are not expanding around a true vacuum of the theory. In this note, we are searching for perturbatively stable examples of type 0' string theory without massless tadpoles in backgrounds with a spatially varying dilaton. We present two examples with this property in non-critical string theories that exhibit four- and six-dimensional Poincare invariance. We discuss the D-branes that can be embedded in this context and the type of gauge theories that can be constructed in this manner. We also comment on the embedding of these non-critical models in critical string theories and their holographic (Little String Theory) interpretation and propose a general conjecture for the role of asymptotic supersymmetry in perturbative string theory.
[ { "version": "v1", "created": "Tue, 15 May 2007 16:03:59 GMT" }, { "version": "v2", "created": "Sat, 28 Jul 2007 15:36:42 GMT" } ]
2009-04-17T00:00:00
[ [ "Israel", "Dan", "" ], [ "Niarchos", "Vasilis", "" ] ]
0705.2141
John Collins
John Collins, Jian-Wei Qiu
k_T factorization is violated in production of high-transverse-momentum particles in hadron-hadron collisions
10 pages. V. 2: Title change, misprints and minor corrections, as in journal version
Phys.Rev.D75:114014,2007
10.1103/PhysRevD.75.114014
ANL-HEP-PR-07-25
hep-ph
null
We show that hard-scattering factorization is violated in the production of high-p_T hadrons in hadron-hadron collisions, in the case that the hadrons are back-to-back, so that k_T factorization is to be used. The explicit counterexample that we construct is for the single-spin asymmetry with one beam transversely polarized. The Sivers function needed here has particular sensitivity to the Wilson lines in the parton densities. We use a greatly simplified model theory to make the breakdown of factorization easy to check explicitly. But the counterexample implies that standard arguments for factorization fail not just for the single-spin asymmetry but for the unpolarized cross section for back-to-back hadron production in QCD in hadron-hadron collisions. This is unlike corresponding cases in e^+e^- annihilation, Drell-Yan, and deeply inelastic scattering. Moreover, the result endangers factorization for more general hadroproduction processes.
[ { "version": "v1", "created": "Tue, 15 May 2007 13:18:18 GMT" }, { "version": "v2", "created": "Thu, 28 Jun 2007 17:54:21 GMT" } ]
2008-11-26T00:00:00
[ [ "Collins", "John", "" ], [ "Qiu", "Jian-Wei", "" ] ]
0705.2142
Michel Pleimling
Michel Pleimling and Ferenc Igloi
Nonequilibrium critical relaxation at a first-order phase transition point
6 pages, 3 figures, version to appear in Europhysics Letters
Europhys. Lett. 79, 56002 (2007)
10.1209/0295-5075/79/56002
null
cond-mat.stat-mech
null
We study numerically the nonequilibrium dynamical behavior of an Ising model with mixed two-spin and four-spin interactions after a sudden quench from the high-temperature phase to the first-order phase transition point. The autocorrelation function is shown to approach its limiting value, given by the magnetization in the ordered phase at the transition point, m_c, through a stretched exponential decay. On the other hand relaxation of the magnetization starting with an uncorrelated initial state with magnetization, m_i, approaches either m_c, for m_i>0.5, or zero, for m_i<0.5. For small m_i and for m_i slightly larger than 0.5 the relaxation of the magnetization shows an asymptotic power-law time dependence, thus from a nonequilibrium point of view the transition is continuous.
[ { "version": "v1", "created": "Tue, 15 May 2007 13:26:07 GMT" }, { "version": "v2", "created": "Thu, 26 Jul 2007 21:19:10 GMT" } ]
2009-11-13T00:00:00
[ [ "Pleimling", "Michel", "" ], [ "Igloi", "Ferenc", "" ] ]
0705.2143
Fabrizio Lillo
Fabrizio Lillo and Marco Span\'o
Inverted and mirror repeats in model nucleotide sequences
12 pages, 6 figures
null
10.1103/PhysRevE.76.041914
null
q-bio.GN q-bio.QM
null
We analytically and numerically study the probabilistic properties of inverted and mirror repeats in model sequences of nucleic acids. We consider both perfect and non-perfect repeats, i.e. repeats with mismatches and gaps. The considered sequence models are independent identically distributed (i.i.d.) sequences, Markov processes and long range sequences. We show that the number of repeats in correlated sequences is significantly larger than in i.i.d. sequences and that this discrepancy increases exponentially with the repeat length for long range sequences.
[ { "version": "v1", "created": "Tue, 15 May 2007 13:37:17 GMT" } ]
2009-11-13T00:00:00
[ [ "Lillo", "Fabrizio", "" ], [ "Spanó", "Marco", "" ] ]
0705.2144
Willem M. de Muynck
Willem M. de Muynck
The Copenhagen interpretation, and pragmatism
Contribution to the Conference on ``Pragmatism & quantum mechanics'', CREA, Ecole Polytechnique & CNRS, Paris, February 22-23, 2007
null
null
null
quant-ph
null
In the past both instrumentalism and empiricism have inspired certain pragmatic elements into the Copenhagen interpretation of quantum mechanics. The relation of such pragmatisms with the correspondence principle is discussed. It is argued that neither Bohr nor Heisenberg did take `correspondence' in one of these forms, and that it, in particular, was Bohr's classical attitude which caused him to apply in an inconsistent way his correspondence principle to the Einstein-Podolsky-Rosen experiment, thus causing much confusion. It is demonstrated that an empiricist pragmatism is conducive to an explanation of violation of the Bell inequalities as a consequence of `complementarity' in the sense of `mutual disturbance in a joint nonideal measurement of incompatible observables' rather than as being caused by `nonlocal influences'.
[ { "version": "v1", "created": "Tue, 15 May 2007 14:27:33 GMT" } ]
2007-05-23T00:00:00
[ [ "de Muynck", "Willem M.", "" ] ]
0705.2145
Paul Feautrier
Paul Feautrier (LIP, INRIA Rh\^one-Alpes)
Elementary transformation analysis for Array-OL
null
null
null
null
cs.PL
null
Array-OL is a high-level specification language dedicated to the definition of intensive signal processing applications. Several tools exist for implementing an Array-OL specification as a data parallel program. While Array-OL can be used directly, it is often convenient to be able to deduce part of the specification from a sequential version of the application. This paper proposes such an analysis and examines its feasibility and its limits.
[ { "version": "v1", "created": "Tue, 15 May 2007 13:44:35 GMT" }, { "version": "v2", "created": "Tue, 22 May 2007 09:52:57 GMT" } ]
2007-05-23T00:00:00
[ [ "Feautrier", "Paul", "", "LIP, INRIA Rhône-Alpes" ] ]
0705.2146
Dori Reichmann
Micha Berkooz and Dori Reichmann
A Short Review of Time Dependent Solutions and Space-like Singularities in String Theory
19 pages; based on Carg\`ese lectures of 2006; to appear in proceedings
Nucl.Phys.Proc.Suppl.171:69-87,2007
10.1016/j.nuclphysbps.2007.06.008
null
hep-th
null
These lecture notes provide a short review of the status of time dependent backgrounds in String theory, and in particular those that contain space-like singularities. Despite considerable efforts, we do not have yet a full and compelling picture of such backgrounds. We review some of the various attempts to understand these singularities via generalizations of the BKL dynamics, using worldsheet methods and using non-perturbative tools such as the AdS/CFT correspondence and M(atrix) theory. These lecture notes are based on talks given at Cargese 06 and the dead-sea conference 06.
[ { "version": "v1", "created": "Tue, 15 May 2007 13:50:29 GMT" } ]
2008-11-26T00:00:00
[ [ "Berkooz", "Micha", "" ], [ "Reichmann", "Dori", "" ] ]
0705.2147
Guilhem Semerjian
Guilhem Semerjian
On the freezing of variables in random constraint satisfaction problems
32 pages, 7 figures
J. Stat. Phys. 130, 251 (2008)
10.1007/s10955-007-9417-7
null
cond-mat.stat-mech cond-mat.dis-nn cs.CC math.PR
null
The set of solutions of random constraint satisfaction problems (zero energy groundstates of mean-field diluted spin glasses) undergoes several structural phase transitions as the amount of constraints is increased. This set first breaks down into a large number of well separated clusters. At the freezing transition, which is in general distinct from the clustering one, some variables (spins) take the same value in all solutions of a given cluster. In this paper we study the critical behavior around the freezing transition, which appears in the unfrozen phase as the divergence of the sizes of the rearrangements induced in response to the modification of a variable. The formalism is developed on generic constraint satisfaction problems and applied in particular to the random satisfiability of boolean formulas and to the coloring of random graphs. The computation is first performed in random tree ensembles, for which we underline a connection with percolation models and with the reconstruction problem of information theory. The validity of these results for the original random ensembles is then discussed in the framework of the cavity method.
[ { "version": "v1", "created": "Tue, 15 May 2007 13:53:10 GMT" } ]
2007-12-19T00:00:00
[ [ "Semerjian", "Guilhem", "" ] ]
0705.2148
Jon Aaronson
Jon Aaronson and Kyewon Koh Park
Predictability, entropy and information of infinite transformations
typos corrected, clarifications added, unproved result removed
Fund. Math. 206 (2009), 1--21
null
null
math.DS math.PR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that a certain type of quasi finite, conservative, ergodic, measure preserving transformation always has a maximal zero entropy factor, generated by predictable sets. We also construct a conservative, ergodic, measure preserving transformation which is not quasi finite; and consider distribution asymptotics of information showing that e.g. for Boole's transformation, information is asymptotically mod-normal with square root normalization. Lastly we see that certain ergodic, probability preserving transformations with zero entropy have analogous properties and consequently entropy dimension of at most 1/2.
[ { "version": "v1", "created": "Tue, 15 May 2007 14:54:46 GMT" }, { "version": "v2", "created": "Tue, 26 Jun 2007 08:52:00 GMT" }, { "version": "v3", "created": "Mon, 12 Nov 2007 16:56:46 GMT" }, { "version": "v4", "created": "Sun, 6 Apr 2008 12:02:06 GMT" }, { "version": "v5", "created": "Fri, 16 Jan 2009 14:17:35 GMT" } ]
2010-06-01T00:00:00
[ [ "Aaronson", "Jon", "" ], [ "Park", "Kyewon Koh", "" ] ]
0705.2149
Ahmad Ghodsi
Mohammad R. Garousi and Ahmad Ghodsi
Entropy Function for Non-extremal D1D5 and D2D6NS5-branes
17 Pages, Latex file; Minor additions, version published in JHEP
JHEP 0710:036,2007
10.1088/1126-6708/2007/10/036
null
hep-th
null
We apply the entropy function formalism to non-extremal D1D5 and D2D6NS5-branes whose throat approximation is given by the Schwarzschild black hole in AdS_3\times S^3\times T^4 and AdS_3\times S^2\times S^1\times T^4, respectively. We find the Bekenstein-Hawking entropy and the (alpha')^3R^4 corrections from the value of the entropy function at its saddle point. While the higher derivative terms have no effect on the temperature, they decrease the value of the entropy.
[ { "version": "v1", "created": "Tue, 15 May 2007 14:05:56 GMT" }, { "version": "v2", "created": "Tue, 25 Sep 2007 10:09:00 GMT" } ]
2009-04-17T00:00:00
[ [ "Garousi", "Mohammad R.", "" ], [ "Ghodsi", "Ahmad", "" ] ]
0705.2150
Ralph Blumenhagen
Nikolas Akerblom, Ralph Blumenhagen, Dieter Lust, Maximilian Schmidt-Sommerfeld
Thresholds for Intersecting D-branes Revisited
14 pages
Phys.Lett.B652:53-59,2007
10.1016/j.physletb.2007.06.060
MPP-2007-55, LMU-ASC 30/07
hep-th
null
Gauge threshold corrections for intersecting D6-brane string models on toroidal orbifold backgrounds are reconsidered. Both by dimensionally regularising the appearing open string one-loop diagrams in tree-channel as well as by zeta-function regularisation of the corresponding loop-channel one-loop diagrams, we arrive at a result which takes into account the infrared divergence from the contribution of the massless states in the running of the gauge coupling constant as well as the contribution of states, which become light in certain regions of the moduli space.
[ { "version": "v1", "created": "Tue, 15 May 2007 14:12:10 GMT" } ]
2008-11-26T00:00:00
[ [ "Akerblom", "Nikolas", "" ], [ "Blumenhagen", "Ralph", "" ], [ "Lust", "Dieter", "" ], [ "Schmidt-Sommerfeld", "Maximilian", "" ] ]
0705.2151
Heide Costantini Dr.
F. Confortola, D. Bemmerer, H. Costantini, A. Formicola, Gy. Gy\"urky, P. Bezzon, R. Bonetti, C. Broggini, P. Corvisiero, Z. Elekes, Zs. F\"ul\"op, G. Gervino, A. Guglielmetti, C. Gustavino, G. Imbriani, M. Junker, M. Laubenstein, A. Lemut, B. Limata, V. Lozza, M. Marta, R. Menegazzo, P. Prati, V. Roca, C. Rolfs, C. Rossi Alvarez, E. Somorjai, O. Straniero, F. Strieder, F. Terrasi, H.P. Trautvetter
Astrophysical S-factor of the 3He(alpha,gamma)7Be reaction measured at low energy via prompt and delayed gamma detection
to be published in Physical Review C
Phys.Rev.C75:065803,2007; Phys.Rev.C75:069903,2007
10.1103/PhysRevC.75.065803
null
nucl-ex astro-ph
null
Solar neutrino fluxes depend both on astrophysical and on nuclear physics inputs, namely on the cross sections of the reactions responsible for neutrino production inside the Solar core. While the flux of solar 8B neutrinos has been recently measured at Superkamiokande with a 3.5% uncertainty and a precise measurement of 7Be neutrino flux is foreseen in the next future, the predicted fluxes are still affected by larger errors. The largest nuclear physics uncertainty to determine the fluxes of 8B and 7Be neutrinos comes from the 3He(alpha,gamma)7Be reaction. The uncertainty on its S-factor is due to an average discrepancy in results obtained using two different experimental approaches: the detection of the delayed gamma rays from 7Be decay and the measurement of the prompt gamma emission. Here we report on a new high precision experiment performed with both techniques at the same time. Thanks to the low background conditions of the Gran Sasso LUNA accelerator facility, the cross section has been measured at Ecm = 170, 106 and 93 keV, the latter being the lowest interaction energy ever reached. The S-factors from the two methods do not show any discrepancy within the experimental errors. An extrapolated S(0)= 0.560+/-0.017 keV barn is obtained. Moreover, branching ratios between the two prompt gamma-transitions have been measured with 5-8% accuracy.
[ { "version": "v1", "created": "Tue, 15 May 2007 14:18:15 GMT" } ]
2008-11-26T00:00:00
[ [ "Confortola", "F.", "" ], [ "Bemmerer", "D.", "" ], [ "Costantini", "H.", "" ], [ "Formicola", "A.", "" ], [ "Gyürky", "Gy.", "" ], [ "Bezzon", "P.", "" ], [ "Bonetti", "R.", "" ], [ "Broggini", "C.", "" ], [ "Corvisiero", "P.", "" ], [ "Elekes", "Z.", "" ], [ "Fülöp", "Zs.", "" ], [ "Gervino", "G.", "" ], [ "Guglielmetti", "A.", "" ], [ "Gustavino", "C.", "" ], [ "Imbriani", "G.", "" ], [ "Junker", "M.", "" ], [ "Laubenstein", "M.", "" ], [ "Lemut", "A.", "" ], [ "Limata", "B.", "" ], [ "Lozza", "V.", "" ], [ "Marta", "M.", "" ], [ "Menegazzo", "R.", "" ], [ "Prati", "P.", "" ], [ "Roca", "V.", "" ], [ "Rolfs", "C.", "" ], [ "Alvarez", "C. Rossi", "" ], [ "Somorjai", "E.", "" ], [ "Straniero", "O.", "" ], [ "Strieder", "F.", "" ], [ "Terrasi", "F.", "" ], [ "Trautvetter", "H. P.", "" ] ]
0705.2152
Paraskevi Tsalmantza
P. Tsalmantza, M. Kontizas, C. A. L. Bailer-Jones, B. Rocca-Volmerange, R. Korakitis, E. Kontizas, E. Livanou, A. Dapergolas, I. Bellas-Velidis, A. Vallenari, M. Fioc
Towards a library of synthetic galaxy spectra and preliminary results of classification and parametrization of unresolved galaxies for Gaia
10 pages, 12 figures, accepted in A&A
null
10.1051/0004-6361:20077300
null
astro-ph
null
Aims:The Gaia astrometric survey mission will, as a consequence of its scanning law, obtain low resolution optical (330-1000 nm) spectrophotometry of several million unresolved galaxies brighter than V=22. We present the first steps in a project to design and implement a classification system for these data. The goal is both to determine morphological classes and to estimate intrinsic astrophysical parameters via synthetic templates. Here we describe (1) a new library of synthetic galaxy spectra, and (2) first results of classification and parametrization experiments using simulated Gaia spectrophotometry of this library. Methods:We have created a large grid of synthetic galaxy spectra using the PEGASE.2 code, which is based on galaxy evolution models that take into account metallicity evolution, extinction correction, emission lines (with stellar spectra based on the BaSeL library). Our classification and regression models are Support Vector Machines (SVMs), which are kernel-based nonlinear estimators. Results:We produce a basic library of about 4000 zero redshift galaxy spectra covering the main Hubble types over wavelength range 250 to 1050 nm at a sampling of 1 nm or less. It is computed on a regular grid of four key astrophysical parameters for each type and for intermediate random values of the same parameters. An extended library reproduces this at a series of redshifts. Initial results from the SVM classifiers and parametrizers are promising, indicating that Hubble types can be reliably predicted and several parameters estimated with low bias and variance. Comparing the colours of our synthetic library with Sloan Digital Sky Survey (SDSS) spectra we find good agreement over the full range of Hubble types and parameters.
[ { "version": "v1", "created": "Tue, 15 May 2007 14:25:06 GMT" }, { "version": "v2", "created": "Thu, 14 Jun 2007 12:39:30 GMT" } ]
2009-11-13T00:00:00
[ [ "Tsalmantza", "P.", "" ], [ "Kontizas", "M.", "" ], [ "Bailer-Jones", "C. A. L.", "" ], [ "Rocca-Volmerange", "B.", "" ], [ "Korakitis", "R.", "" ], [ "Kontizas", "E.", "" ], [ "Livanou", "E.", "" ], [ "Dapergolas", "A.", "" ], [ "Bellas-Velidis", "I.", "" ], [ "Vallenari", "A.", "" ], [ "Fioc", "M.", "" ] ]
0705.2153
Felix Br\"ummer
Felix Bruemmer
A natural renormalizable model of metastable SUSY breaking
9 pages; v2: typos corrected
JHEP0707:043,2007
10.1088/1126-6708/2007/07/043
HD-THEP-07-11
hep-ph hep-th
null
We propose a model of metastable dynamical supersymmetry breaking in which all scales are generated dynamically. Our construction is a simple variant of the Intriligator-Seiberg-Shih model, with quark masses induced by renormalizable couplings to an auxiliary supersymmetric QCD sector. Since all scales arise from dimensional transmutation, the model has no fundamental dimensionful parameters. It also does not rely on higher-dimensional operators.
[ { "version": "v1", "created": "Tue, 15 May 2007 14:46:09 GMT" }, { "version": "v2", "created": "Wed, 30 May 2007 17:43:50 GMT" } ]
2008-11-26T00:00:00
[ [ "Bruemmer", "Felix", "" ] ]
0705.2154
Chiara Zampolli
Chiara Zampolli (1) (for the ALICE Collaboration) ((1) Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Rome, and INFN, Bologna, and Dipartimento di Fisica dell'Universita' di Bologna)
Heavy ion physics with the ALICE experiment at LHC
5 pages, 3 figures, to be published in the Proceedings of the XLII Rencontres de Moriond, QCD and High Energy Hadronic Interaction session, La Thuile, Aosta, Italy, 17-24 March 2007
null
null
null
nucl-ex
null
ALICE is the experiment at the LHC collider at CERN dedicated to heavy ion physics. In this report, the ALICE detector will be presented, together with its expected performance as far as some selected physics topics are concerned.
[ { "version": "v1", "created": "Tue, 15 May 2007 14:47:02 GMT" } ]
2019-08-15T00:00:00
[ [ "Zampolli", "Chiara", "" ] ]
0705.2155
Marcin Paw{\l}owski
Marcin Pawlowski
Monogamy of entanglement as a necessary and sufficient condition for safe QKD in any physical theory
3 Pages, RevTex
null
null
null
quant-ph
null
We show that the monogamy of entanglement is a sufficient phenomenon in every physical theory, if the quantum key distribution is to be safe on the grounds of such theory. To do so we present the QKD protocol that is safe in any physical theory under the assumption of the monogamous entanglement only. The necessity of this condition is also discussed.
[ { "version": "v1", "created": "Tue, 15 May 2007 14:52:14 GMT" } ]
2007-05-23T00:00:00
[ [ "Pawlowski", "Marcin", "" ] ]
0705.2156
Bruno Blind
Bruno Blind (IECN)
Distributions vectorielles homog\`enes sur une alg\`ebre de Jordan
null
Journal of Functional Analysis 208, 2 (03/2004) 482 - 507
null
null
math.FA math.CA
null
We study distributions on a Euclidean Jordan algebra V with values in a finite dimensional representation space for the identity component G of the structure group of V and homogeneous equivariance condition. We show that such distributions exist if and only if the representation is spherical, and that then the dimension of the space of these distributions is r+1 (where r is the rank of V). We give also construction of these distributions and of those that are invariant under the semi-simple part of G.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:00:53 GMT" } ]
2007-05-23T00:00:00
[ [ "Blind", "Bruno", "", "IECN" ] ]
0705.2157
Adrian Bevan
B. Aubert et al. (Babar Collaboration)
A Study of B0 to rho+rho- Decays and Constraints on the CKM Angle alpha
25 pages, submitted to PRD
Phys.Rev.D76:052007,2007
10.1103/PhysRevD.76.052007
SLAC-PUB-12498,BABAR-PUB-07/14
hep-ex
null
We present results from an analysis of B0 to rho+rho- decays using 383.6 million BB-bar pairs collected by the BaBar detector at the PEP-II asymmetric-energy B Factory at SLAC. The measurements of the B0 to rho+rho- branching fraction, longitudinal polarization fraction f_L, and the CP-violating parameters S_{long} and C_{long} are: B(B0-> rho+rho-) = (25.5 +/- 2.1 (stat) +3.6/-3.9 (syst))*10^-6 f_L = 0.992 +/- 0.024 (stat) +0.026/-0.013 (syst) S_{long} = -0.17 +/- 0.20 (stat) +0.05/-0.06 (syst) C_{long} = 0.01 +/- 0.15 (stat) +/- 0.06 (syst) We determine the unitarity triangle angle alpha, using an isospin analysis of B to rhorho decays. One of the two solutions, alpha = [73.1, 117.0] degrees at 68% CL is compatible with standard model-based fits of existing data. Constraints on the unitarity triangle are also evaluated using an SU(3) symmetry based approach.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:01:11 GMT" }, { "version": "v2", "created": "Wed, 11 Jul 2007 11:18:56 GMT" } ]
2010-04-12T00:00:00
[ [ "al.", "B. Aubert et", "", "Babar Collaboration" ] ]
0705.2158
Renzo Cavalieri
Charles Cadman and Renzo Cavalieri
Gerby Localization, Z_3-Hodge Integrals and the GW Theory of C^3/Z_3
Added a section with system of PDE's encoding the recursions
null
null
null
math.AG
null
We exhibit a set of recursive relations that completely determine all equivariant Gromov-Witten invariants of the quotient orbifold C^3/Z_3. We interpret such invariants as G-Hodge Integrals, and produce relations among them via Atiyah-Bott localization on moduli spaces of twisted stable maps to gerbes over the projective line.
[ { "version": "v1", "created": "Tue, 15 May 2007 17:19:21 GMT" }, { "version": "v2", "created": "Wed, 16 May 2007 03:42:43 GMT" }, { "version": "v3", "created": "Wed, 4 Jul 2007 23:15:12 GMT" } ]
2007-07-05T00:00:00
[ [ "Cadman", "Charles", "" ], [ "Cavalieri", "Renzo", "" ] ]
0705.2159
Goranka Bilalbegovic
G. Bilalbegovic
Density functional theory study of (OCS)2^-
pdf (included all figures): http://www.phy.hr/~goranka/Research/ocs.pdf
Chemical Physics Letters 441 (2007) 309-313
10.1016/j.cplett.2007.05.047
null
cond-mat.mtrl-sci physics.atm-clus physics.chem-ph
null
The structural and electronic properties of the carbonyl sulfide dimer anion are calculated using density functional theory within a pseudopotential method. Three geometries are optimized and investigated: C2v and C2 symmetric, as well as one asymmetric structure. A distribution of an excess charge in three isomers are studied by the Hirshfeld method. In an asymmetric (OCS)2^- isomer the charge is not equally divided between the two moieties, but it is distributed as OCS^{-0.6} OCS^{-0.4}. Low-lying excitation levels of three isomers are compared using the time-dependent density functional theory in the Casida approach.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:04:15 GMT" } ]
2007-06-16T00:00:00
[ [ "Bilalbegovic", "G.", "" ] ]
0705.2160
Arend Bayer
Arend Bayer, Charles Cadman
Quantum cohomology of [C^N/\mu_r]
33 pages, 1 figure; v2: expository changes, references updated
Compos. Math., 2010, 146, 1291-1322
10.1112/S0010437X10004793
null
math.AG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We give a construction of the moduli space of stable maps to the classifying stack B\mu_r of a cyclic group by a sequence of r-th root constructions on M_{0, n}. We prove a closed formula for the total Chern class of \mu_r-eigenspaces of the Hodge bundle, and thus of the obstruction bundle of the genus zero Gromov-Witten theory of stacks of the form [C^N/\mu_r]. We deduce linear recursions for all genus-zero Gromov-Witten invariants.
[ { "version": "v1", "created": "Tue, 15 May 2007 16:04:17 GMT" }, { "version": "v2", "created": "Thu, 29 Jan 2009 02:32:48 GMT" } ]
2012-04-06T00:00:00
[ [ "Bayer", "Arend", "" ], [ "Cadman", "Charles", "" ] ]
0705.2161
Leonid Pourovskii
L.V. Pourovskii, B. Amadon, S. Biermann, and A. Georges
Self-consistency over the charge-density in dynamical mean-field theory: a linear muffin-tin implementation and some physical implications
20 pages, 6 figures (submitted in The Physical Review B)
Phys. Rev. B 76, 235101 (2007)
10.1103/PhysRevB.76.235101
null
cond-mat.str-el
null
We present a simple implementation of the dynamical mean-field theory approach to the electronic structure of strongly correlated materials. This implementation achieves full self-consistency over the charge density, taking into account correlation-induced changes to the total charge density and effective Kohn-Sham Hamiltonian. A linear muffin-tin orbital basis-set is used, and the charge density is computed from moments of the many body momentum-distribution matrix. The calculation of the total energy is also considered, with a proper treatment of high-frequency tails of the Green's function and self-energy. The method is illustrated on two materials with well-localized 4f electrons, insulating cerium sesquioxide Ce2O3 and the gamma-phase of metallic cerium, using the Hubbard-I approximation to the dynamical mean-field self-energy. The momentum-integrated spectral function and momentum-resolved dispersion of the Hubbard bands are calculated, as well as the volume-dependence of the total energy. We show that full self-consistency over the charge density, taking into account its modification by strong correlations, can be important for the computation of both thermodynamical and spectral properties, particularly in the case of the oxide material.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:08:37 GMT" } ]
2009-11-13T00:00:00
[ [ "Pourovskii", "L. V.", "" ], [ "Amadon", "B.", "" ], [ "Biermann", "S.", "" ], [ "Georges", "A.", "" ] ]
0705.2162
Agata Ch{\ke}ci\'nska
Agata Ch\c{e}ci\'nska, Krzysztof W\'odkiewicz
Separability of entangled qutrits in noisy channels
19 pages, 5 figures
null
10.1103/PhysRevA.76.052306
null
quant-ph
null
We present an analysis of noisy atomic channels involving qutrits. We choose a three-level atom with V-configuration to be the qutrit state. Gell-Mann matrices and a generalized Bloch vector (8-dimensional) are used to describe the qutrit density operator. We introduce quantum quasi-distributions for qutrits that provide a simple description of entanglement. Studying the time-evolution for the atomic variables we find the Kraus representation of spontaneous emission quantum channel (SE channel). Furthermore, we consider a generalized Werner state of two qutrits and investigate the separability condition in the presence of spontaneous emission noise. The influence of spontaneous emission on the separability of Werner states for qutrit and qubit states is compared.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:09:49 GMT" }, { "version": "v2", "created": "Wed, 16 May 2007 07:29:36 GMT" } ]
2009-11-13T00:00:00
[ [ "Chȩcińska", "Agata", "" ], [ "Wódkiewicz", "Krzysztof", "" ] ]
0705.2163
Fabio Trani
F. Trani, D. Ninno and G. Iadonisi
Tight binding formulation of the dielectric response in semiconductor nanocrystals
9 pages, 5 figures; corrected typos, added references
Physical Review B 76, 085326 (2007)
10.1103/PhysRevB.76.085326
null
cond-mat.mtrl-sci
null
We report on a theoretical derivation of the electronic dielectric response of semiconductor nanocrystals using a tight-binding framework. Extending to the nanoscale the Hanke and Sham approach [Phys. Rev. B 12, 4501 (1975)] developed for bulk semiconductors, we show how local field effects can be included in the study of confined systems. A great advantage of this scheme is that of being formulated in terms of localized orbitals and thus it requires very few computational resources and times. Applications to the optical and screening properties of semiconductor nanocrystals are presented here and discussed. Results concerning the absorption cross section, the static polarizability and the screening function of InAs (direct gap) and Si (indirect gap) nanocrystals compare well to both first principles results and experimental data. We also show that the present scheme allows us to easily go beyond the continuum dielectric model, based on the Clausius-Mossotti equation, which is frequently used to include the nanocrystal surface polarization. Our calculations indicate that the continuum dielectric model, used in conjunction with a size dependent dielectric constant, underestimates the nanocrystal polarizability, leading to exceedingly strong surface polarization fields.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:10:42 GMT" }, { "version": "v2", "created": "Fri, 17 Aug 2007 09:55:37 GMT" } ]
2011-11-09T00:00:00
[ [ "Trani", "F.", "" ], [ "Ninno", "D.", "" ], [ "Iadonisi", "G.", "" ] ]
0705.2164
Ji-Lin Zhou
Ji-Lin Zhou (NJU), Douglas N.C. Lin (UCO/Lick), Yi-Sui Sun (NJU)
Post-Oligarchic Evolution of Protoplanetary Embryos and the Stability of Planetary Systems
15 pages, 13 figures (2 color ones), accepted for publication in ApJ
Astrophys.J.666:423-435,2007
10.1086/519918
null
astro-ph
null
We investigate the orbit-crossing time (T_c) of protoplanet systems both with and without a gas-disk background. The protoplanets are initially with equal masses and separation (EMS systems) scaled by their mutual Hill's radii. In a gas-free environment, we find log (T_c/yr) = A+B \log (k_0/2.3). Through a simple analytical approach, we demonstrate that the evolution of the velocity dispersion in an EMS system follows a random walk. The stochastic nature of random-walk diffusion leads to (i) an increasing average eccentricity <e> ~ t^1/2, where t is the time; (ii) Rayleigh-distributed eccentricities (P(e,t)=e/\sigma^2 \exp(-e^2/(2\sigma^2)) of the protoplanets; (iii) a power-law dependence of T_c on planetary separation. As evidence for the chaotic diffusion, the observed eccentricities of known extra solar planets can be approximated by a Rayleigh distribution. We evaluate the isolation masses of the embryos, which determine the probability of gas giant formation, as a function of the dust and gas surface densities.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:16:25 GMT" } ]
2009-06-23T00:00:00
[ [ "Zhou", "Ji-Lin", "", "NJU" ], [ "Lin", "Douglas N. C.", "", "UCO/Lick" ], [ "Sun", "Yi-Sui", "", "NJU" ] ]
0705.2165
Mario Ponce
M. Ponce
Local dynamics for fibered holomorphic transformations
null
null
10.1088/0951-7715/20/12/011
null
math.DS
null
Fibered holomorphic dynamics are skew-product transformations over an irrational rotation, whose fibers are holomorphic functions. In this paper we study such a dynamics on a neighborhood of an invariant curve. We obtain some results analogous to the results in the non fibered case.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:20:24 GMT" } ]
2011-11-07T00:00:00
[ [ "Ponce", "M.", "" ] ]
0705.2166
Antonio Alfonso-Faus
Antonio Alfonso-Faus
Ultimate Fate of our Universe from Quantum Mechanics
null
null
null
null
physics.gen-ph
null
It is conjectured that time intervals of any kind are proportional to the age of the Universe taken at the time we are considering the interval. If this is the case then the speed of light, in fact any speed, must decrease inversely proportional to this age. The immediate consequence is that energy is not conserved: the hypothesis that time is a homogeneous property implies conservation of energy (the theorem of Noether). Nonconservation of energy follows from the condition that any time interval is proportional to the cosmological time, and therefore time can not be homogeneous. From the uncertainty principle, taking the constant of Planck as a real constant, time independent, it follows that any energy in the Universe decreases linearly with time. We then prove that Schroedinger equation does not change, except for the potential energy term. The future of the Universe gives for the wave functions a long sinusoidal spatial solution, so that everything becomes unlocalized. The relativistic absolute interval remains the same, even with a changing speed of light, and the Universe turns out to be nonexpanding. A Mass-Boom effect is confirmed.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:35:09 GMT" } ]
2007-05-23T00:00:00
[ [ "Alfonso-Faus", "Antonio", "" ] ]
0705.2167
Vladimir Korenev
V.L. Korenev
The Nuclear Spin Nanomagnet
19 pages, including 3 figures. Short version has been accepted for publication in Physical Review Letters
Physical Review Letters 99 256405 (2007)
10.1103/PhysRevLett.99.256405
null
cond-mat.mes-hall
null
Linearly polarized light tuned slightly below the optical transition of the negatively charged exciton (trion) in a single quantum dot causes the spontaneous nuclear spin polarization (self-polarization) at a level close to 100%. The effective magnetic field of spin-polarized nuclei brings the optical transition energy into resonance with photon energy. The resonantly enhanced Overhauser effect sustains the stability of the nuclear self-polarization even in the absence of spin polarization of the quantum dot electron. As a result the optically selected single quantum dot represents a tiny magnet with the ferromagnetic ordering of nuclear spins - the nuclear spin nanomagnet.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:23:13 GMT" }, { "version": "v2", "created": "Thu, 11 Oct 2007 11:01:16 GMT" } ]
2008-04-02T00:00:00
[ [ "Korenev", "V. L.", "" ] ]
0705.2168
Gerard Schiffmann Prof
Steve Rallis and G\'erard Schiffmann
Multiplicity one Conjectures
111 pages, no figures
null
null
null
math.RT
null
In the first part, in the local non archimedean case, we consider distributions on GL(n+1) which are invariant under the adjoint action of GL(n). We conjecture that such distributions are invariant by transposition. This would imply multiplicity at most one for restrictions from GL(n+1) to GL(n). We reduce ourselves to distributions with "singular" support and then finish the proof for n< 9. In the second part we show that similar Theorems for orthogonal or unitary groups follow from the case of GL(n)
[ { "version": "v1", "created": "Tue, 15 May 2007 15:39:20 GMT" } ]
2007-05-23T00:00:00
[ [ "Rallis", "Steve", "" ], [ "Schiffmann", "Gérard", "" ] ]
0705.2169
Huben Ganev G
H. G. Ganev
Collective states of the odd-mass nuclei within the framework of the Interacting Vector Boson Model
18 pages, 8 figures
J.Phys.G35:125101,2008
10.1088/0954-3899/35/12/125101
null
nucl-th
null
A supersymmetric extension of the dynamical symmetry group $Sp^{B}(12,R)$ of the Interacting Vector Boson Model (IVBM), to the orthosymplectic group $OSp(2\Omega/12,R)$ is developed in order to incorporate fermion degrees of freedom into the nuclear dynamics and to encompass the treatment of odd mass nuclei. The bosonic sector of the supergroup is used to describe the complex collective spectra of the neighboring even-even nuclei and is considered as a core structure of the odd nucleus. The fermionic sector is represented by the fermion spin group $SO^{F}(2\Omega)\supset SU^{F}(2)$. The so obtained, new exactly solvable limiting case is applied for the description of the nuclear collective spectra of odd mass nuclei. The theoretical predictions for different collective bands in three odd mass nuclei, namely $^{157}Gd$, $^{173}Yb$ and $^{163}Dy$ from rare earth region are compared with the experiment. The $B(E2)$ transition probabilities for the $^{157}Gd$ and $^{163}Dy$ between the states of the ground band are also studied. The important role of the symplectic structure of the model for the proper reproduction of the $B(E2)$ behavior is revealed. The obtained results reveal the applicability of the models extension.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:24:08 GMT" }, { "version": "v2", "created": "Fri, 11 Apr 2008 22:55:15 GMT" } ]
2008-11-26T00:00:00
[ [ "Ganev", "H. G.", "" ] ]
0705.2170
Krzysztof R. Apt
Krzysztof R. Apt and Arantza Est\'evez-Fern\'andez
Sequential mechanism design
28 pages
null
null
null
cs.GT
null
In the customary VCG (Vickrey-Clarke-Groves) mechanism truth-telling is a dominant strategy. In this paper we study the sequential VCG mechanism and show that other dominant strategies may then exist. We illustrate how this fact can be used to minimize taxes using examples concerned with Clarke tax and public projects.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:24:16 GMT" } ]
2016-08-14T00:00:00
[ [ "Apt", "Krzysztof R.", "" ], [ "Estévez-Fernández", "Arantza", "" ] ]
0705.2171
Myungkook Jee
M.J. Jee, H.C. Ford, G.D. Illingworth, R.L. White, T.J. Broadhurst, D.A. Coe, G.R. Meurer, A. Van Der Wel, N. Benitez, J.P. Blakeslee, R.J. Bouwens, L.D. Bradley, R. Demarco, N.L. Homeier, A.R. Martel, and S. Mei
Discovery of a Ringlike Dark Matter Structure in the Core of the Galaxy Cluster Cl 0024+17
To appear in the June 1 issue of The Astrophysical Journal
Astrophys.J.661:728-749,2007
10.1086/517498
null
astro-ph
null
We present a comprehensive mass reconstruction of the rich galaxy cluster Cl 0024+17 at z~0.4 from ACS data, unifying both strong- and weak-lensing constraints. The weak-lensing signal from a dense distribution of background galaxies (~120 per square arcmin) across the cluster enables the derivation of a high-resolution parameter-free mass map. The strongly-lensed objects tightly constrain the mass structure of the cluster inner region on an absolute scale, breaking the mass-sheet degeneracy. The mass reconstruction of Cl 0024+17 obtained in such a way is remarkable. It reveals a ringlike dark matter substructure at r~75" surrounding a soft, dense core at r~50". We interpret this peculiar sub-structure as the result of a high-speed line-of-sight collision of two massive clusters 1-2 Gyr ago. Such an event is also indicated by the cluster velocity distribution. Our numerical simulation with purely collisionless particles demonstrates that such density ripples can arise by radially expanding, decelerating particles that originally comprised the pre-collision cores. Cl 0024+17 can be likened to the bullet cluster 1E0657-56, but viewed $along$ the collision axis at a much later epoch. In addition, we show that the long-standing mass discrepancy for Cl 0024+17 between X-ray and lensing can be resolved by treating the cluster X-ray emission as coming from a superposition of two X-ray systems. The cluster's unusual X-ray surface brightness profile that requires a two isothermal sphere description supports this hypothesis.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:52:56 GMT" } ]
2009-09-29T00:00:00
[ [ "Jee", "M. J.", "" ], [ "Ford", "H. C.", "" ], [ "Illingworth", "G. D.", "" ], [ "White", "R. L.", "" ], [ "Broadhurst", "T. J.", "" ], [ "Coe", "D. A.", "" ], [ "Meurer", "G. R.", "" ], [ "Van Der Wel", "A.", "" ], [ "Benitez", "N.", "" ], [ "Blakeslee", "J. P.", "" ], [ "Bouwens", "R. J.", "" ], [ "Bradley", "L. D.", "" ], [ "Demarco", "R.", "" ], [ "Homeier", "N. L.", "" ], [ "Martel", "A. R.", "" ], [ "Mei", "S.", "" ] ]
0705.2172
Karine Sartelet
Karine Sartelet (CEREA), Hiroshi Hayami (CRIEPI), Bruno Sportisse (CEREA)
Dominant aerosol processes during high-pollution episodes over Greater Tokyo
Journal of Geophysical Research D: Atmospheres (15/05/2007) in press
null
10.1029/2006JD007885
null
physics.ao-ph
null
This paper studies two high-pollution episodes over Greater Tokyo: 9 and 10 December 1999, and 31 July and 1 August 2001. Results obtained with the chemistry-transport model (CTM) Polair3D are compared to measurements of inorganic PM2.5. To understand to which extent the aerosol processes modeled in Polair3D impact simulated inorganic PM2.5, Polair3D is run with different options in the aerosol module, e.g. with/without heterogeneous reactions. To quantify the impact of processes outside the aerosol module, simulations are also done with another CTM (CMAQ). In the winter episode, sulfate is mostly impacted by condensation, coagulation, long-range transport, and deposition to a lesser extent. In the summer episode, the effect of long-range transport largely dominates. The impact of condensation/evaporation is dominant for ammonium, nitrate and chloride in both episodes. However, the impact of the thermodynamic equilibrium assumption is limited. The impact of heterogeneous reactions is large for nitrate and ammonium, and taking heterogeneous reactions into account appears to be crucial in predicting the peaks of nitrate and ammonium. The impact of deposition is the same for all inorganic PM2.5. It is small compared to the impact of other processes although it is not negligible. The impact of nucleation is negligible in the summer episode, and small in the winter episode. The impact of coagulation is larger in the winter episode than in the summer episode, because the number of small particles is higher in the winter episode as a consequence of nucleation.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:34:54 GMT" } ]
2015-05-13T00:00:00
[ [ "Sartelet", "Karine", "", "CEREA" ], [ "Hayami", "Hiroshi", "", "CRIEPI" ], [ "Sportisse", "Bruno", "", "CEREA" ] ]
0705.2173
Dorje C. Brody
Dorje C. Brody
Note on exponential families of distributions
5 pages
J. Phys. A: Math. Theor. 40 (2007) F691--F695
10.1088/1751-8113/40/30/F01
null
cond-mat.stat-mech
null
We show that an arbitrary probability distribution can be represented in exponential form. In physical contexts, this implies that the equilibrium distribution of any classical or quantum dynamical system is expressible in grand canonical form.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:39:48 GMT" } ]
2007-10-25T00:00:00
[ [ "Brody", "Dorje C.", "" ] ]
0705.2174
F. S. Bergeret
F. S. Bergeret, A. F. Volkov and K. B. Efetov
Nonhomogeneous magnetization and superconductivity in superconductor-ferromagnet structures
null
Physica C, Vol. 367, 107 (2002)
10.1016/S0921-4534(01)00975-3
null
cond-mat.supr-con cond-mat.mes-hall
null
We study two different superconductor-ferromagnet (S/F) structures. We consider first a Josephson junction which consists of two S/F bilayers separated by an insulating layer. We show that for an antiparallel alignment of the magnetization in the two F layers the Josephson critical current $I_c$ increases with increasing exchange field $h$. The second system we consider is a S/F structure with a local inhomogeneity of the magnetization in the ferromagnet near the S/F interface. Due to the proximity effect not only a singlet but also a triplet component of the superconducting condensate is induced in the ferromagnet. The latter penetrates over the length $\sqrt{D/\epsilon}$ ($D$ is the diffusion coefficient and $\epsilon$ the energy). In the case of temperatures of the order of the Thouless energy this length is comparable to the length of the ferromagnet. This long-range penetration leads to a significant increase of the ferromagnet conductance below the superconducting critical temperature $T_c$. Contrary to the case of the singlet component, the contribution to the conductance due to the odd triplet component is not zero at $T = 0$ and $V = 0$ ($V$ is the voltage) and decays with increasing temperature T in a monotonic way
[ { "version": "v1", "created": "Tue, 15 May 2007 15:39:59 GMT" } ]
2009-11-13T00:00:00
[ [ "Bergeret", "F. S.", "" ], [ "Volkov", "A. F.", "" ], [ "Efetov", "K. B.", "" ] ]
0705.2175
Peter Petreczky
P. Petreczky
Progress in Lattice QCD at finite temperature
Talk presented at 23rd Winter Workshop on Nuclear Dynamics, Latex, 8 pages, 5 figures, uses bigsky2007.sty. Typos corrected, further discussion of Tc is added
null
null
BNL-NT-07/20
nucl-th
null
I review recent developements in lattice QCD at finite temperature, including the determination of the transition temperature T_c, equation of state and diffenet static screening lengths. The lattice data suggest that at temperatures above 1.5T_c the quark gluon plasma can be considered as gas consisting of quarks and gluons.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:54:30 GMT" }, { "version": "v2", "created": "Fri, 18 May 2007 15:22:02 GMT" }, { "version": "v3", "created": "Sat, 19 May 2007 14:56:50 GMT" } ]
2007-05-23T00:00:00
[ [ "Petreczky", "P.", "" ] ]
0705.2176
Federico Urban
C. Bambi, F.R. Urban
Gravitational particle production in braneworld cosmology
4 pages, 1 figure, v3 with new definition of $\Lambda$ and minor text modifications
Phys.Rev.Lett.99:191302,2007
10.1103/PhysRevLett.99.191302
null
hep-ph astro-ph.CO gr-qc
null
Gravitational particle production in time variable metric of an expanding universe is efficient only when the Hubble parameter $H$ is not too small in comparison with the particle mass. In standard cosmology, the huge value of the Planck mass $M_{Pl}$ makes the mechanism phenomenologically irrelevant. On the other hand, in braneworld cosmology the expansion rate of the early universe can be much faster and many weakly interacting particles can be abundantly created. Cosmological implications are discussed.
[ { "version": "v1", "created": "Tue, 15 May 2007 15:47:05 GMT" }, { "version": "v2", "created": "Mon, 21 May 2007 08:34:51 GMT" }, { "version": "v3", "created": "Mon, 19 Nov 2007 08:13:49 GMT" } ]
2009-06-12T00:00:00
[ [ "Bambi", "C.", "" ], [ "Urban", "F. R.", "" ] ]
0705.2177
Mark Rudner
M. S. Rudner and L. S. Levitov
Resonant Cooling of Nuclear Spins in Quantum Dots
4 pages, 4 figures
null
null
null
cond-mat.mes-hall
null
We propose to use the spin-blockade regime in double quantum dots to reduce nuclear spin polarization fluctuations in analogy with optical Doppler cooling. The Overhauser shift brings electron levels in and out of resonance, creating feedback to suppress fluctuations. Coupling to the disordered nuclear spin background is a major source of noise and dephasing in electron spin measurements in such systems. Estimates indicate that a better than 10-fold reduction of fluctuations is possible.
[ { "version": "v1", "created": "Tue, 15 May 2007 17:54:00 GMT" } ]
2007-05-23T00:00:00
[ [ "Rudner", "M. S.", "" ], [ "Levitov", "L. S.", "" ] ]
0705.2178
Narciso Roman-Roy
M. Barbero-Li\~nan, A. Echeverria-Enriquez, D. Martin de Diego, M.C. Mu\~noz-Lecanda, N. Roman-Roy
Skinner-Rusk Unified Formalism for Optimal Control Systems and Applications
26 pp. Replaced with the published version. Section 2 has been shortened. Minor mistakes are corrected
J. Phys. A: Math. Theor. 40 (2007) 12071--12093
10.1088/1751-8113/40/40/005
null
math-ph math.MP
null
A geometric approach to time-dependent optimal control problems is proposed. This formulation is based on the Skinner and Rusk formalism for Lagrangian and Hamiltonian systems. The corresponding unified formalism developed for optimal control systems allows us to formulate geometrically the necessary conditions given by Pontryagin's Maximum Principle, provided that the differentiability with respect to controls is assumed and the space of controls is open. Furthermore, our method is also valid for implicit optimal control systems and, in particular, for the so-called descriptor systems (optimal control problems including both differential and algebraic equations).
[ { "version": "v1", "created": "Tue, 15 May 2007 16:02:50 GMT" }, { "version": "v2", "created": "Thu, 18 Oct 2007 14:57:20 GMT" } ]
2015-12-15T00:00:00
[ [ "Barbero-Liñan", "M.", "" ], [ "Echeverria-Enriquez", "A.", "" ], [ "de Diego", "D. Martin", "" ], [ "Muñoz-Lecanda", "M. C.", "" ], [ "Roman-Roy", "N.", "" ] ]
0705.2179
Gabor Elek
Gabor Elek and Balazs Szegedy
Limits of Hypergraphs, Removal and Regularity Lemmas. A Non-standard Approach
25 pages
null
null
null
math.CO
null
We study the integral and measure theory of the ultraproduct of finite sets. As a main application we construct limit objects for hypergraph sequences. We give a new proof for the Hypergraph Removal Lemma and the Hypergraph Regularity Lemma.
[ { "version": "v1", "created": "Tue, 15 May 2007 16:03:11 GMT" } ]
2007-05-23T00:00:00
[ [ "Elek", "Gabor", "" ], [ "Szegedy", "Balazs", "" ] ]
0705.2180
Amir Yacoby
J. Martin, N. Akerman, G. Ulbricht, T. Lohmann, J. H. Smet, K. von Klitzing, and A. Yacoby
Observation of Electron-Hole Puddles in Graphene Using a Scanning Single Electron Transistor
13 pages, 5 figures
null
10.1038/nphys781
null
cond-mat.mes-hall cond-mat.str-el
null
The electronic density of states of graphene is equivalent to that of relativistic electrons. In the absence of disorder or external doping the Fermi energy lies at the Dirac point where the density of states vanishes. Although transport measurements at high carrier densities indicate rather high mobilities, many questions pertaining to disorder remain unanswered. In particular, it has been argued theoretically, that when the average carrier density is zero, the inescapable presence of disorder will lead to electron and hole puddles with equal probability. In this work, we use a scanning single electron transistor to image the carrier density landscape of graphene in the vicinity of the neutrality point. Our results clearly show the electron-hole puddles expected theoretically. In addition, our measurement technique enables to determine locally the density of states in graphene. In contrast to previously studied massive two dimensional electron systems, the kinetic contribution to the density of states accounts quantitatively for the measured signal. Our results suggests that exchange and correlation effects are either weak or have canceling contributions.
[ { "version": "v1", "created": "Tue, 15 May 2007 16:03:46 GMT" } ]
2015-05-13T00:00:00
[ [ "Martin", "J.", "" ], [ "Akerman", "N.", "" ], [ "Ulbricht", "G.", "" ], [ "Lohmann", "T.", "" ], [ "Smet", "J. H.", "" ], [ "von Klitzing", "K.", "" ], [ "Yacoby", "A.", "" ] ]
0705.2181
Fengyuan Yang
X. W. Zhao, T. R. Lemberger, and F. Y. Yang
Growth control of GaAs nanowires using pulsed laser deposition with arsenic over pressure
null
null
10.1088/0957-4484/18/48/485608
null
cond-mat.mtrl-sci
null
Using pulsed laser ablation with arsenic over pressure, the growth conditions for GaAs nanowires have been systematically investigated and optimized. Arsenic over pressure with As$_2$ molecules was introduced to the system by thermal decomposition of polycrystalline GaAs to control the stoichiometry and shape of the nanowires during growth. GaAs nanowires exhibit a variety of geometries under varying arsenic over pressure, which can be understood by different growth processes via vapor-liquid-solid mechanism. Single-crystal GaAs nanowires with uniform diameter, lengths over 20 $\mu$m, and thin surface oxide layer were obtained and can potentially be used for further electronic characterization.
[ { "version": "v1", "created": "Tue, 15 May 2007 19:59:52 GMT" } ]
2009-11-13T00:00:00
[ [ "Zhao", "X. W.", "" ], [ "Lemberger", "T. R.", "" ], [ "Yang", "F. Y.", "" ] ]
0705.2182
Michael Zieve
Ariane M. Masuda and Michael E. Zieve
Rational functions with linear relations
8 pages
Proc. Amer. Math. Soc. 136 (2008), 1403--1408
null
null
math.NT math.DS
null
We find all polynomials f,g,h over a field K such that g and h are linear and f(g(x))=h(f(x)). We also solve the same problem for rational functions f,g,h, in case the field K is algebraically closed.
[ { "version": "v1", "created": "Tue, 15 May 2007 16:08:33 GMT" } ]
2008-06-09T00:00:00
[ [ "Masuda", "Ariane M.", "" ], [ "Zieve", "Michael E.", "" ] ]
0705.2183
Andrea De Simone
Andrea De Simone, Antonio Riotto
On Resonant Leptogenesis
16 pages, 7 figures. IOP LaTeX class used. Minor corrections and references added. Matches the version published in JCAP
JCAP0708:013,2007
10.1088/1475-7516/2007/08/013
MIT-CTP-3832
hep-ph
null
It has been recently shown that the quantum Boltzmann equations may be relevant for the leptogenesis scenario. In particular, they lead to a time-dependent CP asymmetry which depends upon the previous dynamics of the system. This memory effect in the CP asymmetry is particularly important in resonant leptogenesis where the asymmetry is generated by the decays of nearly mass-degenerate right-handed neutrinos. We study the impact of the nontrivial time evolution of the CP asymmetry in resonant leptogenesis, both in the one-flavour case and with flavour effects included. We show that significant qualitative and quantitative differences arise with respect to the case in which the time dependence of the CP asymmetry is neglected.
[ { "version": "v1", "created": "Tue, 15 May 2007 16:19:52 GMT" }, { "version": "v2", "created": "Tue, 2 Oct 2007 23:40:58 GMT" } ]
2008-11-26T00:00:00
[ [ "De Simone", "Andrea", "" ], [ "Riotto", "Antonio", "" ] ]
0705.2184
Fabio Tonoli
Fabrizio Catanese (Universitaet Bayreuth), Fabio Tonoli (Universita' di Trento)
A remarkable moduli space of rank 6 vector bundles related to cubic surfaces
39 pages, to appear in "Vector bundles and low codimensional subvarieties: state of the art and recent developments" in the Series "Quaderni di Matematica" della Seconda Universita' di Napoli
null
null
null
math.AG
null
We study the moduli space $\fM^s(6;3,6,4)$ of simple rank 6 vector bundles $\E$ on $\PP^3$ with Chern polynomial $1+3t+6t^2+4t^3$ and properties of these bundles, especially we prove some partial results concerning their stability. We first recall how these bundles are related to the construction of sextic nodal surfaces in $\PP^3$ having an even set of 56 nodes (cf. \cite{CaTo}). We prove that there is an open set, corresponding to the simple bundles with minimal cohomology, which is irreducible of dimension 19 and bimeromorphic to an open set $\fA^0$ of the G.I.T. quotient space of the projective space $\fB:=\{B\in \PP(U^\vee\otimes W\otimes V^\vee)\}$ of triple tensors of type $(3,3,4)$ by the natural action of $SL(W)\times SL(U)$. We give several constructions for these bundles, which relate them to cubic surfaces in 3-space $\PP^3$ and to cubic surfaces in the dual space $(\PP^3)^{\vee}$. One of these constructions, suggested by Igor Dolgachev, generalizes to other types of tensors. Moreover, we relate the socalled {\em cross-product involution} for $(3,3,4)$-tensors, introduced in \cite{CaTo}, with the Schur quadric associated to a cubic surface in $\PP^3$ and study further properties of this involution.
[ { "version": "v1", "created": "Tue, 15 May 2007 16:15:17 GMT" } ]
2007-05-23T00:00:00
[ [ "Catanese", "Fabrizio", "", "Universitaet Bayreuth" ], [ "Tonoli", "Fabio", "", "Universita'\n di Trento" ] ]
0705.2185
Finelli Fabio
F. Di Marco, F. Finelli, A. Gruppuso
Evolution of Large Scale Curvature Fluctuations During the Perturbative Decay of the Inflaton
9 pages, 2 figures; v2: version published in PRD
Phys.Rev.D76:043530,2007
10.1103/PhysRevD.76.043530
null
astro-ph
null
We study the evolution of cosmological fluctuations during and after inflation driven by a scalar field coupled to a perfect fluid through afriction term. During the slow-roll regime for the scalar field, the perfect fluid is also frozen and isocurvature perturbations are generated. After the end of inflation, during the decay of the inflaton, we find that a change in the observationally relevant large scale curvature fluctuations is possible.
[ { "version": "v1", "created": "Tue, 15 May 2007 16:17:26 GMT" }, { "version": "v2", "created": "Wed, 10 Oct 2007 15:04:43 GMT" } ]
2008-12-18T00:00:00
[ [ "Di Marco", "F.", "" ], [ "Finelli", "F.", "" ], [ "Gruppuso", "A.", "" ] ]
0705.2186
Ananthnarayan H
H. Ananthnarayan
The Gorenstein Colength of an Artinian Local Ring
The title and layout have changed, has been shortened to 9 pages. Published in Journal of Algebra
Journal of Algebra 320 (2008) 3438-3446
10.1016/j.jalgebra.2008.08.017
null
math.AC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we make the notion of approximating an Artinian local ring by a Gorenstein Artin local ring precise using the concept of Gorenstein colength. We also answer the question as to when the Gorenstein colength is at most two.
[ { "version": "v1", "created": "Tue, 15 May 2007 16:28:22 GMT" }, { "version": "v2", "created": "Fri, 24 Oct 2008 20:24:25 GMT" } ]
2008-10-24T00:00:00
[ [ "Ananthnarayan", "H.", "" ] ]
0705.2187
Roni Ilan
Roni Ilan, Eytan Grosfeld and Ady Stern
Coulomb blockade as a probe for non-Abelian statistics in Read-Rezayi states
Published version
Phys. Rev. Lett. 100, 086803 (2008)
10.1103/PhysRevLett.100.086803
null
cond-mat.mes-hall
null
We consider a quantum dot in the regime of the quantum Hall effect, particularly in Laughlin states and non-Abelian Read-Rezayi states. We find the location of the Coulomb blockade peaks in the conductance as a function of the area of the dot and the magnetic field. When the magnetic field is fixed and the area of the dot is varied, the peaks are equally spaced for the Laughlin states. In contrast, non-Abelian statistics is reflected in modulations of the spacing which depend on the magnetic field.
[ { "version": "v1", "created": "Tue, 15 May 2007 16:29:29 GMT" }, { "version": "v2", "created": "Wed, 20 Jun 2007 08:32:26 GMT" }, { "version": "v3", "created": "Tue, 27 May 2008 12:49:21 GMT" } ]
2009-11-13T00:00:00
[ [ "Ilan", "Roni", "" ], [ "Grosfeld", "Eytan", "" ], [ "Stern", "Ady", "" ] ]
0705.2188
Douglas M. Slauson
Sergio Albeverio, Palle E.T. Jorgensen, Anna M. Paolucci
Multiresolution wavelet analysis of integer scale Bessel functions
Research paper, 32 pages
null
10.1063/1.2750291
null
math.RT math.OA
null
We identify multiresolution subspaces giving rise via Hankel transforms to Bessel functions. They emerge as orthogonal systems derived from geometric Hilbert-space considerations, the same way the wavelet functions from a multiresolution scaling wavelet construction arise from a scale of Hilbert spaces. We study the theory of representations of the $C^{\ast}$-algebra $% O_{\nu +1}$ arising from this multiresolution analysis. A connection with Markov chains and representations of $O_{\nu +1}$ is found. Projection valued measures arising from the multiresolution analysis give rise to a Markov trace for quantum groups $SO_q$.
[ { "version": "v1", "created": "Tue, 15 May 2007 16:36:57 GMT" }, { "version": "v2", "created": "Wed, 16 May 2007 14:17:16 GMT" } ]
2009-11-13T00:00:00
[ [ "Albeverio", "Sergio", "" ], [ "Jorgensen", "Palle E. T.", "" ], [ "Paolucci", "Anna M.", "" ] ]
0705.2189
Pavlo Pylyavskyy
Thomas Lam, Pavlo Pylyavskyy
Combinatorial Hopf algebras and K-homology of Grassmanians
35 pages, 10 figures
null
null
null
math.CO math.AG
null
Motivated by work of Buch on set-valued tableaux in relation to the K-theory of the Grassmannian, we study six combinatorial Hopf algebras. These Hopf algebras can be thought of as K-theoretic analogues of the by now classical ``square'' of Hopf algebras consisting of symmetric functions, quasisymmetric functions, noncommutative symmetric functions and the Malvenuto-Reutenauer Hopf algebra of permutations. In addition, we develop a theory of set-valued P-partitions and study three new families of symmetric functions which are weight generating functions of reverse plane partitions, weak set-valued tableaux and valued-set tableaux.
[ { "version": "v1", "created": "Tue, 15 May 2007 16:56:10 GMT" } ]
2007-05-23T00:00:00
[ [ "Lam", "Thomas", "" ], [ "Pylyavskyy", "Pavlo", "" ] ]
0705.2190
Michael Graesser
Michael L. Graesser
Experimental Constraints on Higgs Boson Decays to TeV-scale Right-Handed Neutrinos
38 pages, 5 figures
null
null
RUNHETC-04-2007
hep-ph
null
The existence of neutrino masses strongly suggests that right-handed neutrinos exist, but the data do not favor any particular scale for the Majorana mass parameters. Here I explore the possibility that these particles exist at the electroweak scale along with additional new physics at the TeV scale . Higher dimension operators involving right-handed neutrinos and the Higgs boson can introduce new decay modes of the Higgs boson, significantly modifying its phenomenology if it is light. With minimal flavor violation the Higgs boson cascade decays to 6 particles containing two highly displaced vertices. Each displaced vertex produces an odd number of leptons, leading to a dramatic signature of overall lepton violation at each vertex. I discuss the limits from the Tevatron, and find that they are close to exploring interesting regions of parameters, while limiting others. Moving beyond minimal flavor violation, cascade decays of the Higgs boson into as many as 14 particles can occur.
[ { "version": "v1", "created": "Tue, 15 May 2007 16:47:32 GMT" } ]
2007-05-23T00:00:00
[ [ "Graesser", "Michael L.", "" ] ]
0705.2191
Dmitry Krotov
Victor Alexandrov, Dmitry Krotov, Andrey Losev, Vyacheslav Lysov
On Pure Spinor Superfield Formalism
null
JHEP 0710:074,2007
10.1088/1126-6708/2007/10/074
INR/TH-24-2006, ITEP/TH -37/06
hep-th math-ph math.MP math.QA
null
We show that a certain superfield formalism can be used to find an off-shell supersymmetric description for some supersymmetric field theories where conventional superfield formalism does not work. This "new" formalism contains even auxiliary variables in addition to conventional odd super-coordinates. The idea of this construction is similar to the pure spinor formalism developed by N.Berkovits. It is demonstrated that using this formalism it is possible to prove that the certain Chern-Simons-like (Witten's OSFT-like) theory can be considered as an off-shell version for some on-shell supersymmetric field theories. We use the simplest non-trivial model found in [2] to illustrate the power of this pure spinor superfield formalism. Then we redo all the calculations for the case of 10-dimensional Super-Yang-Mills theory. The construction of off-shell description for this theory is more subtle in comparison with the model of [2] and requires additional Z_2 projection. We discover experimentally (through a direct explicit calculation) a non-trivial Z_2 duality at the level of Feynman diagrams. The nature of this duality requires a better investigation.
[ { "version": "v1", "created": "Tue, 15 May 2007 16:58:43 GMT" }, { "version": "v2", "created": "Thu, 31 May 2007 12:03:59 GMT" } ]
2009-04-22T00:00:00
[ [ "Alexandrov", "Victor", "" ], [ "Krotov", "Dmitry", "" ], [ "Losev", "Andrey", "" ], [ "Lysov", "Vyacheslav", "" ] ]
0705.2192
Joseph C. Shields
Hagai Netzer (Tel Aviv U.), Joseph C. Shields (Ohio U.)
Conference Summary: The Central Engine of Active Galactic Nuclei
12 pages, Conference proceedings to appear in "The Central Engine of Active Galactic Nuclei", ed. L. C. Ho and J.-M. Wang (San Francisco: ASP)
null
null
null
astro-ph
null
The 2006 meeting in Xi'an on the Central Engine of Active Galactic Nuclei covered the enormous and continuously expanding area of AGN research, from theory to the most sophisticated observations and from gamma-ray energies to long radio wavelengths. This short summary gives some, but definitely not all, highlights and new results presented by the participants.
[ { "version": "v1", "created": "Tue, 15 May 2007 17:14:56 GMT" } ]
2007-05-23T00:00:00
[ [ "Netzer", "Hagai", "", "Tel Aviv U." ], [ "Shields", "Joseph C.", "", "Ohio U." ] ]
0705.2193
Kirill Tuchin
Kirill Tuchin
Forward hadron production in high energy pA collisions: from RHIC to LHC
16 pages, 8 figures; discussion added and a few typos corrected
Nucl.Phys.A798:61-73,2008
10.1016/j.nuclphysa.2007.10.008
RBRC-670
hep-ph nucl-ex nucl-th
null
We present a calculation of Pi, D and B mesons production at RHIC and LHC energies based upon the KKT model of gluon saturation. We discuss dependence of the nuclear modification factor on rapidity and transverse momentum.
[ { "version": "v1", "created": "Tue, 15 May 2007 17:28:45 GMT" }, { "version": "v2", "created": "Wed, 14 Nov 2007 20:09:21 GMT" } ]
2008-11-26T00:00:00
[ [ "Tuchin", "Kirill", "" ] ]
0705.2194
Kuiroukidis
A Kuiroukidis, K Kleidis, D B Papadopoulos and L Vlahos
Excitation of MHD waves in magnetized anisotropic cosmologies
12 pages, RevTex, 5 figures ps, accepted for publication to Astronomy and Astrophysics
null
10.1051/0004-6361:20077109
null
gr-qc
null
The excitation of cosmological perturbations in an anisotropic cosmological model and in the presence of a homogeneous magnetic field was studied, using the resistive magnetohydrodynamic (MHD) equations. We have shown that fast-magnetosonic modes, propagating normal to the magnetic field grow exponentially and saturated at high values, due to the resistivity. We also demonstrate that the jeans-like instabilities are enhanced inside a resistive and the formation of condensations formed within an anisotropic fluid influence the growing magnetosonic waves.
[ { "version": "v1", "created": "Tue, 15 May 2007 17:29:47 GMT" } ]
2009-11-13T00:00:00
[ [ "Kuiroukidis", "A", "" ], [ "Kleidis", "K", "" ], [ "Papadopoulos", "D B", "" ], [ "Vlahos", "L", "" ] ]
0705.2195
Taner Akgun
Taner Akgun and Ira Wasserman (Cornell University)
Toroidal Magnetic Fields in Type II Superconducting Neutron Stars
32 pages, 6 figures; derivations shortened, comments and references added; accepted for publication in MNRAS
Mon.Not.Roy.Astron.Soc.383:1551-1580,2008
10.1111/j.1365-2966.2007.12660.x
null
astro-ph
null
We determine constraints on the form of axisymmetric toroidal magnetic fields dictated by hydrostatic balance in a type II superconducting neutron star with a barotropic equation of state. Using Lagrangian perturbation theory, we find the quadrupolar distortions due to such fields for various models of neutron stars with type II superconducting and normal regions. We find that the star becomes prolate and can be sufficiently distorted to display precession with a period of the order of years. We also study the stability of such fields using an energy principle, which allows us to extend the stability criteria established by R. J. Tayler for normal conductors to more general media with magnetic free energy that depends on density and magnetic induction, such as type II superconductors. We also derive the growth rate and instability conditions for a specific instability of type II superconductors, first discussed by P. Muzikar, C. J. Pethick and P. H. Roberts, using a local analysis based on perturbations around a uniform background.
[ { "version": "v1", "created": "Tue, 15 May 2007 19:55:21 GMT" }, { "version": "v2", "created": "Tue, 15 May 2007 20:14:16 GMT" }, { "version": "v3", "created": "Thu, 1 Nov 2007 17:15:19 GMT" } ]
2009-11-16T00:00:00
[ [ "Akgun", "Taner", "", "Cornell University" ], [ "Wasserman", "Ira", "", "Cornell University" ] ]
0705.2196
Heather Thompson
H. M. A. Thompson, F. P. Keenan, P. L. Dufton, R. S. I. Ryans, J. V. Smoker, D. L. Lambert and A. A. Zijlstra
Iron abundances of B-type post-Asymptotic Giant Branch stars in globular clusters: Barnard 29 in M 13 and ROA 5701 in omega Cen
15 pages, 3 figures. Accepted for publication in MNRAS
Mon.Not.Roy.Astron.Soc.378:1619-1632,2007
10.1111/j.1365-2966.2007.11916.x
null
astro-ph
null
High resolution optical and ultraviolet spectra of two B-type post-Asymptotic Giant Branch (post-AGB) stars in globular clusters, Barnard 29 in M 13 and ROA 5701 in omega Cen, have been analysed using model atmosphere techniques. The optical spectra have been obtained with FEROS on the ESO 2.2-m telescope and the 2d-Coud\'e spectrograph on the 2.7-m McDonald telescope, while the ultraviolet observations are from the GHRS on the HST. Abundances of light elements (C, N, O, Mg, Al and S) plus Fe have been determined from the optical spectra, while the ultraviolet data provide additional Fe abundance estimates from Fe III absorption lines in the 1875-1900 {\AA} wavelength region. A general metal underabundance relative to young B-type stars is found for both Barnard 29 and ROA 5701. These results are consistent with the metallicities of the respective clusters, as well as with previous studies of the objects. The derived abundance patterns suggest that the stars have not undergone a gas-dust separation, contrary to previous suggestions, although they may have evolved from the AGB before the onset of the third dredge-up. However, the Fe abundances derived from the HST spectra are lower than those expected from the metallicities of the respective clusters, by 0.5 dex for Barnard 29 and 0.8 dex for ROA 5701. A similar systematic underabundance is also found for other B-type stars in environments of known metallicity, such as the Magellanic Clouds. These results indicate that the Fe III ultraviolet lines may yield abundance values which are systematically too low by typically 0.6 dex and hence such estimates should be treated with caution.
[ { "version": "v1", "created": "Tue, 15 May 2007 18:57:53 GMT" } ]
2009-06-23T00:00:00
[ [ "Thompson", "H. M. A.", "" ], [ "Keenan", "F. P.", "" ], [ "Dufton", "P. L.", "" ], [ "Ryans", "R. S. I.", "" ], [ "Smoker", "J. V.", "" ], [ "Lambert", "D. L.", "" ], [ "Zijlstra", "A. A.", "" ] ]
0705.2197
Steven B. Giddings
Steven B. Giddings
Black holes, information, and locality
v2: minor updates to agree w/published version
Mod.Phys.Lett.A22:2949-2954,2007
10.1142/S0217732307025923
null
hep-th gr-qc
null
Thirty years of a deepening information paradox suggest the need to revise our basic physical framework. Multiple indicators point toward reassessment of the principle of locality: lack of a precise definition in quantum gravity, behavior of high-energy scattering, hints from strings and AdS/CFT, conundrums of quantum cosmology, and finally lack of good alternative resolutions of the paradox. A plausible conjecture states that the non-perturbative dynamics of gravity is unitary but nonlocal. String theory may directly address these issues but so far important aspects remain elusive. If this viewpoint is correct, critical questions are to understand the "correspondence" limit where nonlocal physics reduces to local quantum field theory, and beyond, to unveil principles of an underlying nonlocal theory.
[ { "version": "v1", "created": "Tue, 15 May 2007 19:18:44 GMT" }, { "version": "v2", "created": "Tue, 5 Feb 2008 04:12:27 GMT" } ]
2008-11-26T00:00:00
[ [ "Giddings", "Steven B.", "" ] ]