Extensions of the generalized hedgehog ansatz for the Einstein-nonlinear σ-model system: black holes with NUT, black strings and time-dependent solutions

The temperature-dependence of proton electric conductivity in hydrogen-bonded molecular systems with damping effect was studied. The time-dependent velocity of proton and its mobility are determined from the Hamiltonian of a model system. The calculated mobility of (3.57–3.76) × 10-6 m 2/ Vs for uniform ice is in agreement with the experimental value of (1 - 10) × 10-2 m 2/ Vs . When the temperature and damping effects of the medium are considered, the mobility is found to depend on the temperature for various electric field values in the system, i.e. the mobility increases initially and reaches a maximum at about 191 K, but decreases subsequently to a minimum at approximately 241 K, and increases again in the range of 150–270 K. This behavior agrees with experimental data of ice.

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Rotating charged black strings and three-dimensional black holes

Physical Review D ◽

10.1103/physrevd.54.3840 ◽

1996 ◽

Vol 54 (6) ◽

pp. 3840-3853 ◽

Cited By ~ 204

Author(s):

José P. S. Lemos ◽

Vilson T. Zanchin

Keyword(s):

Black Holes ◽

Three Dimensional ◽

Black Strings

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Amplifying the Hawking Signal in BECs

Advances in High Energy Physics ◽

10.1155/2014/713574 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 7

Author(s):

Roberto Balbinot ◽

Alessandro Fabbri

Keyword(s):

Black Holes ◽

Casimir Effect ◽

Pair Creation ◽

Time Dependent ◽

Dynamical Casimir Effect ◽

Hawking Effect ◽

Acoustic Black Holes ◽

Bose Einstein ◽

Simple Models

We consider simple models of Bose-Einstein condensates to study analog pair-creation effects, namely, the Hawking effect from acoustic black holes and the dynamical Casimir effect in rapidly time-dependent backgrounds. We also focus on a proposal by Cornell to amplify the Hawking signal in density-density correlators by reducing the atoms’ interactions shortly before measurements are made.

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Monte Carlo Simulations of the 2+1 Dimensional Fokker-Planck Equation: Spherical Star Clusters Containing Massive, Central Black Holes

Symposium - International Astronomical Union ◽

10.1017/s0074180900147618 ◽

1985 ◽

Vol 113 ◽

pp. 373-413 ◽

Cited By ~ 2

Author(s):

Stuart L. Shapiro

Keyword(s):

Black Holes ◽

Monte Carlo ◽

Black Hole ◽

Phase Space ◽

Star Clusters ◽

Galactic Nuclei ◽

Planck Equation ◽

Time Dependent ◽

Central Black Hole ◽

Fokker Planck Equation

The dynamical behavior of a relaxed star cluster containing a massive, central black hole poses a challenging problem for the theorist and intriguing possibilities for the observer. The historical development of the subject is sketched and the salient features of the physical solution and its observational consequences are summarized.The full dynamical problem of a relaxed, self-gravitating, large N-body system containing a massive central black hole has all the necessary ingredients to excite the most dispassionate many-body, computational physicist: it is a time-dependent, multidimensional, nonlinear problem which must be solved over widely disparate length and time scales simultaneously. The problem has been tackled at various levels of approximation over the years. A new 2+1 dimensional Monte Carlo simulation code has been developed in appreciable generality to solve the time-dependent Fokker-Planck equation in E-J space for this problem. The code incorporates such features as (1) a particle “cloning and renormalization” scheme to provide a statistically reliable population of test particles in low density regions of phase space and (2) a time-step “adjustment” algorithm to ensure integration on local relaxation timescales without having to follow typical particles on orbital trajectories. However, critical regions in phase space (e.g. disruption “loss-cone” trajectories) can still be followed on orbital timescales. Numerical results obtained with this Monte Carlo scheme for the dynamical structure and evolution of globular star clusters and dense galactic nuclei containing massive black holes are reviewed.Recent dynamical integrations of the Einstein field equations for spherical, collisionless (Vlasov) systems in General Relativity suggest a possible origin for the supermassive black holes believed to power quasars and active galactic nuclei. This scenario is discussed briefly.

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