scholarly journals Action complexity for semi-classical black holes

2020 ◽  
Vol 2020 (7) ◽  
Author(s):  
Lukas Schneiderbauer ◽  
Watse Sybesma ◽  
Lárus Thorlacius
Keyword(s):  
Black Holes ◽  
Classical Black Holes

Tidal deformation of quantum black holes

2021 ◽  
pp. 2142011
Author(s):  
Ram Brustein ◽  
Yotam Sherf
Keyword(s):  
Black Holes ◽  
Perturbation Theory ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Excited Level ◽  
Love Number ◽  
Standard Time ◽  
Love Numbers ◽  
Classical Black Holes ◽  
Quantum Perturbation Theory

The response of a gravitating object to an external tidal field is encoded in its Love numbers, which identically vanish for classical black holes (BHs). Here we show, using standard time-independent quantum perturbation theory, that for a quantum BH, generically, the Love numbers are nonvanishing and negative. We calculate the quadrupolar electric quantum Love number of slowly rotating BHs and show that it depends most strongly on the first excited level of the quantum BH. Finally, we discuss the detectability of the quadrupolar quantum Love number in future precision gravitational-wave observations and show that, under favourable circumstances, its magnitude is large enough to imprint an observable signature on the gravitational waves emitted during the inspiral. Phase of two moderately spinning BHs.

NONCOMMUTATIVE D-BRANE WORLD, BLACK HOLES AND EXTRA DIMENSIONS

2009 ◽  
Vol 24 (18n19) ◽  
pp. 3571-3576 ◽  
Author(s):  
SUPRIYA KAR
Keyword(s):  
Black Holes ◽  
String Theory ◽  
Extra Dimensions ◽  
Space Time ◽  
Brane World ◽  
Spherically Symmetric ◽  
Axially Symmetric ◽  
Ordinary Space ◽  
Classical Black Holes ◽  
Type Iib String Theory

Inspired by the space-time noncommutativity on a D5-brane world, in a type IIB string theory, we explore the possibility of an emergent 4D ordinary space-time in the formalism. In particular, a curved D3-brane dynamics is worked out to obtain an axially symmetric and a spherically symmetric AdS and dS black holes. Extremal geometries are analyzed, using the noncommutative scaling. The emerging two dimensional semi-classical black holes are investigated to yield evidence for extra dimensions in the curved brane-world. Interestingly, a tunneling between dS to AdS vacua in the formalism is briefly discussed by incorporating the Hagedorn transitions in string theory.

scholarly journals Quantum gravity as an emergent phenomenon

2019 ◽  
Vol 28 (14) ◽  
pp. 1944003 ◽  
Author(s):  
Shounak De ◽  
Tejinder P. Singh ◽  
Abhinav Varma
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Quantum Gravity ◽  
Closed String ◽  
Emergent Phenomenon ◽  
Statistical Fluctuations ◽  
Far From Equilibrium ◽  
Classical Black Holes ◽  
Low Entropy ◽  
Emergent Theory

There ought to exist a reformulation of quantum theory which does not depend on classical time. To achieve such a reformulation, we introduce the concept of an atom of space-time-matter (STM). An STM atom is a classical noncommutative geometry (NCG), based on an asymmetric metric, and sourced by a closed string. Different such atoms interact via entanglement. The statistical thermodynamics of a large number of such atoms gives rise, at equilibrium, to a theory of quantum gravity. Far from equilibrium, where statistical fluctuations are large, the emergent theory reduces to classical general relativity. In this theory, classical black holes are far from equilibrium low entropy states, and their Hawking evaporation represents an attempt to return to the [maximum entropy] equilibrium quantum gravitational state.

scholarly journals HORIZON MASS THEOREM

2005 ◽  
Vol 14 (12) ◽  
pp. 2219-2225 ◽  
Author(s):  
YUAN K. HA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Uniqueness Theorem ◽  
Hawking Radiation ◽  
General Theorem ◽  
Positive Energy ◽  
Singularity Theorem ◽  
Area Theorem ◽  
Classical Black Holes ◽  
The Uniqueness Theorem

A new theorem for black holes is found. It is called the horizon mass theorem. The horizon mass is the mass which cannot escape from the horizon of a black hole. For all black holes, neutral, charged or rotating, the horizon mass is always twice the irreducible mass observed at infinity. Previous theorems on black holes are: (i) the singularity theorem, (ii) the area theorem, (iii) the uniqueness theorem, (iv) the positive energy theorem. The horizon mass theorem is possibly the last general theorem for classical black holes. It is crucial for understanding Hawking radiation and for investigating processes occurring near the horizon.

scholarly journals Photon Spheres, ISCOs, and OSCOs: Astrophysical Observables for Regular Black Holes with Asymptotically Minkowski Cores

Universe ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 2
Author(s):  
Thomas Berry ◽  
Alex Simpson ◽  
Matt Visser
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Circular Orbit ◽  
Schwarzschild Black Hole ◽  
Circular Orbits ◽  
Regular Black Hole ◽  
Astrophysical Interest ◽  
Regular Black Holes ◽  
Recent Advances ◽  
Classical Black Holes

Classical black holes contain a singularity at their core. This has prompted various researchers to propose a multitude of modified spacetimes that mimic the physically observable characteristics of classical black holes as best as possible, but that crucially do not contain singularities at their cores. Due to recent advances in near-horizon astronomy, the ability to observationally distinguish between a classical black hole and a potential black hole mimicker is becoming increasingly feasible. Herein, we calculate some physically observable quantities for a recently proposed regular black hole with an asymptotically Minkowski core—the radius of the photon sphere and the extremal stable timelike circular orbit (ESCO). The manner in which the photon sphere and ESCO relate to the presence (or absence) of horizons is much more complex than for the Schwarzschild black hole. We find situations in which photon spheres can approach arbitrarily close to (near extremal) horizons, situations in which some photon spheres become stable, and situations in which the locations of both photon spheres and ESCOs become multi-valued, with both ISCOs (innermost stable circular orbits) and OSCOs (outermost stable circular orbits). This provides an extremely rich phenomenology of potential astrophysical interest.

scholarly journals Black-hole boundaries

2005 ◽  
Vol 83 (11) ◽  
pp. 1073-1099 ◽  
Author(s):  
Ivan Booth
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Recent Work ◽  
Numerical Relativity ◽  
Null Infinity ◽  
Event Horizons ◽  
Traditional Definition ◽  
Classical Black Holes ◽  
Definition Of ◽  
Future Null Infinity

Classical black holes and event horizons are highly nonlocal objects, defined in relation to the causal past of future null infinity. Alternative, quasilocal characterizations of black holes are often used in mathematical, quantum, and numerical relativity. These include apparent, Killing, trapping, isolated, dynamical, and slowly evolving horizons. All of these are closely associated with two-surfaces of zero outward null expansion. This paper reviews the traditional definition of black holes and provides an overview of some of the more recent work on alternative horizons.PACS Nos.: 04.20.Cv, 04.70.–s, 04.70.Bw

Sign in / Sign up

Export Citation Format

Share Document