118511063
Exact black hole formation in three dimensions
Abstract We consider three dimensional Einstein gravity non-minimally coupled to a real scalar field with a self-interacting scalar potential and present the exact black hole formation in three dimensions. Firstly we obtain an exact time-dependent spherically symmetric solution describing the gravitational collapse to a scalar black hole at the infinite time, i.e. in the static limit. The solution can only be asymptotically AdS because of the No–Go theorem in three dimensions which is resulting from the existence of a smooth black hole horizon. Then we analyze their geometric properties and properties of the time evolution. We also get the exact time-dependent solution in the minimal coupling model after taking a conformal transformation.
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.
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.
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
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.
119245563
FIVE-DIMENSIONAL VACUUM EINSTEIN SPACETIMES IN C-METRIC LIKE COORDINATES
A five-dimensional Einstein spacetime with (non)vanishing cosmological constant is analyzed in detail. The metric is in close analogy with the four-dimensional massless uncharged C-metric in many aspects. The coordinate system, horizons and causal structures, relations to standard form of de Sitter, anti de Sitter and Minkowski vacua are investigated. After a boost and Kaluza–Klein reduction, we get an exact solution of four-dimensional Einstein–Maxwell–Liouville theory which reduces to a solution to Einstein–Liouville theory in the limit of zero boost velocity and to that of Einstein–Maxwell–dilaton theory in the case of zero cosmological constant.
122609851
Study of split higher order mode resonances in superconducting cavities
Abstract Split resonances are a common appearance in superconducting cavities and are studied here on a specific example. A five cell superconducting cavity suitable for the envisioned electron-hadron collider eRHIC was designed and will be used in the upcoming “Coherent electron Cooling” Proof-of-Principle experiment. The superconducting cavity is intended for high-current applications, and beam stability depends on minimizing the Higher Order Modes (HOM). This was attempted in the design phase and will be done with appropriate mode dampers in operation. The design was implemented as a copper cavity and two Niobium cavities were fabricated. The availability of the copper model provided a convenient opportunity to confirm the design and to study potentially nefarious HOMs. Selected high- Q resonances were investigated via bead pull measurements. The appearance of split resonances impeded their study and suitable methods of HOM identification are presented in this report.
123588064
Design, simulations, and conditioning of 500 kW fundamental power couplers for a superconducting rf gun
6908824
NGN, QCD 2 and chiral phase transition from string theory
We construct a D2-D8-8 configuration in string theory, it can be described at low energy by two dimensional field theory. In the weak coupling region, the low energy theory is a nonlocal generalization of Gross-Neveu(GN) model which dynamically breaks the chiral flavor symmetry U(Nf)L × U(Nf)R at large Nc and finite Nf. However, in the strong coupling region, we can use the SUGRA/Born-Infeld approximation to describe the low energy dynamics of the system. Also, we analyze the low energy dynamics about the configuration of wrapping the one direction of D2 brane on a circle with anti-periodic boundary condition of fermions. The fermions and scalars on D2 branes get mass and decouple from the low energy theory. The IR dynamics is described by the QCD2 at weak coupling. In the opposite region, the dynamics has a holographic dual description. And we have discussed the phase transition of chiral symmetry breaking at finite temperature. Finally, after performing T-duality, this configuration is related to some other brane configurations.
17939294
Yang-Type Monopoles In 5 Dimensional Curved Space-Time
Motivated by Gibbons and Townsend's recent work, we construct Yang-Type monopoles in maximally symmetric space-time. We then analyze the dependence of horizon structure of the space-times around the 5-dimensional monopoles on the relative strength of gravitations to Yang-Mills interactions. We also analyze the stability of the monopoles against tensor type perturbations on metrics.
16407162
Asymptotic limits and sum rules for the quark propagator
Abstract For the structure functions of the quark propagator, the asymptotic behavior is obtained for general, linear, covariant gauges, and in all directions of the complex k 2 -plane. Asymptotic freedom is assumed. Corresponding previous results for the gauge field propagator are important in the derivation. Except for coefficients, the leading asymptotic terms are determined by one-loop or by two-loop information, and are gauge independent. Various sum rules are derived.