1,099 research outputs found
Exact results for corner contributions to the entanglement entropy and Renyi entropies of free bosons and fermions in 3d
In the presence of a sharp corner in the boundary of the entanglement region,
the entanglement entropy (EE) and Renyi entropies for 3d CFTs have a
logarithmic term whose coefficient, the corner function, is scheme-independent.
In the limit where the corner becomes smooth, the corner function vanishes
quadratically with coefficient for the EE and for the Renyi
entropies. For a free real scalar and a free Dirac fermion, we evaluate
analytically the integral expressions of Casini, Huerta, and Leitao to derive
exact results for and for all . The results
for agree with a recent universality conjecture of Bueno, Myers, and
Witczak-Krempa that in all 3d CFTs, where is the
central charge. For the Renyi entropies, the ratios do not
indicate similar universality. However, in the limit , the
asymptotic values satisfy a simple relationship and equal times
the asymptotic values of the free energy of free scalars/fermions on the
-covered 3-sphere.Comment: 10 pages, 2 figures. v2: typos corrected, references added,
asymptotics update
Bicycling Black Rings
We present detailed physics analyses of two different 4+1-dimensional
asymptotically flat vacuum black hole solutions with spin in two independent
planes: the doubly spinning black ring and the bicycling black ring system
("bi-rings"). The latter is a new solution describing two concentric orthogonal
rotating black rings which we construct using the inverse scattering technique.
We focus particularly on extremal zero-temperature limits of the solutions. We
construct the phase diagram of currently known zero-temperature vacuum black
hole solutions with a single event horizon, and discuss the non-uniqueness
introduced by more exotic black hole configurations such as bi-rings and
multi-ring saturns.Comment: 32 pages, 12 figure
Dynamics and Stability of Black Rings
We examine the dynamics of neutral black rings, and identify and analyze a
selection of possible instabilities. We find the dominating forces of very thin
black rings to be a Newtonian competition between a string-like tension and a
centrifugal force. We study in detail the radial balance of forces in black
rings, and find evidence that all fat black rings are unstable to radial
perturbations, while thin black rings are radially stable. Most thin black
rings, if not all of them, also likely suffer from Gregory-Laflamme
instabilities. We also study simple models for stability against
emission/absorption of massless particles. Our results point to the conclusion
that most neutral black rings suffer from classical dynamical instabilities,
but there may still exist a small range of parameters where thin black rings
are stable. We also discuss the absence of regular real Euclidean sections of
black rings, and thermodynamics in the grand-canonical ensemble.Comment: 39 pages, 17 figures; v2: conclusions concerning radial stability
corrected + new appendix + refs added; v3: additional comments regarding
stabilit
Multi-black rings and the phase diagram of higher-dimensional black holes
Configurations of multiple concentric black rings play an important role in
determining the pattern of branchings, connections and mergers between
different phases of higher-dimensional black holes. We examine them using both
approximate and (in five dimensions) exact methods. By identifying the role of
the different scales in the system, we argue that it is possible to have
multiple black ring configurations in which all the rings have equal
temperature and angular velocity. This allows us to correct and improve in a
simple, natural manner, an earlier proposal for the phase diagram of
singly-rotating black holes in .Comment: 14 pages, 2 figure
static black holes with event horizon topology
We present numerical evidence for the existence of new black hole solutions
in spacetime dimensions. They approach asymptotically the Minkowski
background and have an event horizon topology . These static
solutions share the basic properties of the nonrotating black rings in five
dimensions, in particular the presence of a conical singularity.Comment: 10 pages, 4 figure
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