119196245
A note on entropy relations of black hole horizons
Black holes with multi-horizons may provide new ways to understand the intrinsic thermodynamics. In this work, we focus on the entropy relations of black holes in three, four and higher dimensions. These entropy relations include entropy product, "part" entropy product and entropy sum. We also discuss their differences and similarities, in order to make a further study on understanding the origin of black hole entropy at the microscopic level.
119069530
Landau meets Newton: time translation symmetry breaking in classical mechanics
AbstractEvery classical Newtonian mechanical system can be equipped with anonstandard Hamiltonian structure, in which the Hamiltonian is the squareof the canonical Hamiltonian up to a constant shift, and the Poisson bracketis nonlinear. In such a formalism, time translation symmetry can be spon-taneously broken, provided the potential function becomes negative. A niceanalogy between time translation symmetry breaking and the Landau the-ory of second order phase transitions is established, together with severalexample cases illustrating time translation breaking ground states. In par-ticular, the CDM model of FRW cosmology is reformulated as the timetranslation symmetry breaking ground states.Keywords: time translation symmetry breaking, Hamiltonian formalism,Landau theory of phase transition, CDM modelPACS: 1 Introduction Spontaneous symmetry breaking plays an essential role in many areas in moderntheoretical physics such as the gauge theory of particle physics and the Landau-Ginzberg theory of phase transitions in condensed matter physics. Spontaneouslybroken symmetries can either be internal symmetry (such as gauge and chiralsymmetries) or spacial symmetry (such as space translation and rotation symme-tries). Shapere and Wilczek recently discovered [1] that even the time translationsymmetry can be spontaneously broken in some singular Lagrangian systems. Ina previous work [2], we showed that the spontaneous breaking of time transla-tion symmetry can also be described in Hamiltonian formalism using some non-1
55487930
Thermodynamics of rotating black holes with scalar hair in three dimensions
Introducing a new form of scalar potential $V(\ensuremath{\phi})$, we derive a proper form of the rotating black hole solution in three-dimensional Einstein gravity with nonminimally coupled scalar field and find that the first law of thermodynamics of this new rotating hairy black hole can be protected, where the scalar field parameter $B$ is constrained to relate to the black hole size. We also disclose the Hawking\char21{}Page phase transition between this rotating hairy black holes and the pure thermal radiation. Moreover, we study phase transitions between this rotating hairy black hole and rotating Banados-Teitelboim-Zanelli (BTZ) black hole. Considering the matchings for the temperature and angular momentum, we find that the rotating BTZ black hole always has smaller free energy, which is a thermodynamically more preferred phase. Additionally, we evaluate the thermodynamics of the rotating black hole with minimally coupled scalar hair in three dimensions, which exhibits that the thermodynamical behaviors of this rotating hairy black hole are very similar to those of the rotating black hole with nonminimally coupled scalar hair.
122503839
Properties of an Accelerating Gauss-Bonnet Vacuum in Five Dimensions
The causal structure of a five-dimensional C-metric like vacuum solution of Gauss-Bonnet gravity is analyzed in detail, the Gauss-Bonnet parameter make it more complex than that of a C-metric like solution of Einstein gravity. The acceleration of the observer fixed at a spatial position is calculated, the effect of the Gauss-Bonnet parameter comes in, but the acceleration of the origin is not affected by the parameter. The geodesics of the test particles in the spacetime are investigated, it is found that objects accelerate to go to the horizon in the accelerating spacetime.
118418619
Novel rotating hairy black hole in (2+1)-dimensions
We present some novel rotating hairy black hole metric in (2 + 1) dimensions, which is an exact solution to the field equations of the Einstein-scalar-AdS theory with a non-minimal coupling. The scalar potential is determined by the metric ansatz and consistency of the field equations and cannot be prescribed arbitrarily. In the simplified, critical case, the scalar potential contains two independent constant parameters, which are respectively related to the mass and angular momentum of the black hole in a particular way. As long as the angular momentum does not vanish, the metric can have zero, one or two horizons. The case with no horizon is physically uninteresting because of the curvature singularity lying at the origin. We identify the necessary conditions for at least one horizon to be present in the solution, which imposes some bound on the mass-angular momentum ratio. For some particular choice of parameters our solution degenerates into some previously known black hole solutions.
119257757
Accelerating BTZ spacetime
An exact solution of (2 + 1)-dimensional Einstein gravity with a cosmological constant is studied. The corresponding spacetime is interpreted as an accelerating BTZ spacetime. The proper acceleration, horizon structure, temperature and entropy are presented in detail. The metric being studied is very similar to the one studied by Astorino (2011 J. High Energy Phys. JHEP01(2011)114) but the range of parameters is different which results in significant changes in the causal structures.
118838150
Recent Heavy Flavor Results at RHIC
We summarize the recent experimental results of heavy favor physics from the Relativistic Heavy Ion Collider (RHIC) in Brookhaven National Lab (BNL) at Long Island, New York, USA.We will discuss the directly reconstructed open charm mesons as well as electrons from heavy favor hadron decays. The charm and bottom quark production cross-sections have also been measured. We will also discuss JPsi and Upsilon states in p+p and heavy ion collisions. The studies described here were carried out and reported by the STAR and PHENIX collaborations at RHIC.
208866876
The high transverse momentum non-photonic electron measurements in Au + Au collisions at sNN = 200 GeV at RHIC
We present preliminary results of Non-Photonic Electron (NPE) production, NPE-hadron azimuthal correlation as well as NPE elliptic flow studies at midrapidity using a data set with high statistics and low photon conversion background from Au + Au collisions at sNN = 200 GeV collected at RHIC in Run 2010.
209945196
A method for the separation and reconstructions of charged hadron and neutral hadron from their overlapped showers in an electromagnetic calorimeter
The separation and reconstructions of charged hadron and neutral hadron from their overlapped showers in an electromagnetic calorimeter is very important for the reconstructions of some particles with hadronic decays, for example the tau reconstruction in the searches for the Standard Model and supersymmetric Higgs bosons at the LHC. In this paper, a method combining the shower cluster in an electromagnetic calorimeter and the parametric formula for hadron showers, was developed to separate the overlapped showers between charged hadron and neutral hadron. Taking the hadronic decay containing one charged pion and one neutral pion in the final status of tau for example, satisfied results of the separation of the overlapped showers, the reconstructions of the energy and positions of the hadrons were obtained. An improved result for the tau reconstruction with this decay model can be also achieved after the application of the proposed method.
118592667
Holographic model with a NS-NS field
We consider a holographic model constructed through using the D4/D8-$\overline{\rm D8}$ brane configuration with a background field. We study some properties of the effective field theory in this intersecting brane construction, and calculate the effects of this NS-NS background field on some underlying dynamics. We also discuss some other general brane configurations.
118561275
Test of the prototype of electron detector for LHAASO project using cosmic rays
LHAASO project is to be built in south-west China, which use an array of 5137 election detectors for the measurement of the incident electrons arriving at the detector plane. For the quality control of the big quantity of electron detectors, a cosmic ray hodoscope with two-dimensional spacial sensitivity and good time resolution has been developed. The ?rst prototype of electron detector is tested with the hodoscope and the performance of the detector is validated to be consistent with the design.