scholarly journals Motion of particles and gravitational lensing around the (2+1)-dimensional BTZ black hole in Gauss–Bonnet gravity

2021 ◽  
Vol 81 (9) ◽  
Author(s):  
Bakhtiyor Narzilloev ◽  
Sanjar Shaymatov ◽  
Ibrar Hussain ◽  
Ahmadjon Abdujabbarov ◽  
Bobomurat Ahmedov ◽  
...  
Keyword(s):  
Black Hole ◽  
Gravitational Lensing ◽  
Coupling Constant ◽  
Btz Black Hole ◽  
Bending Angle ◽  
Four Dimensions ◽  
Approach Distance ◽  
Test Particles ◽  
The One ◽  
Peak Value

AbstractWe study the motion of test particles and photons in the vicinity of the (2+1)-dimensional Gauss–Bonnet (GB) BTZ black hole. We find that the presence of the coupling constant serves as an attractive gravitational charge, shifting the innermost stable circular orbits outward with respect to the one for this theory in four dimensions. Further, we consider the gravitational lensing, to test the GB gravity in (2+1) dimensions and show that the presence of the GB parameter causes the bending angle to first increase with the increase in the inverse of the closest approach distance, $$u_0$$ u 0 , reaching a peak value for a specific $$u_0^*$$ u 0 ∗ , and then decreasing to zero. We also show that the increase in the value of the GB parameter decreases the bending angle, and the increase in the absolute value of the negative cosmological constant produces an opposite effect on this angle.

scholarly journals Deflection of light around a rotating BTZ black hole

2020 ◽  
Vol 35 (39) ◽  
pp. 2050323
Author(s):  
Shubham Kala ◽  
Hemwati Nandan ◽  
Prateek Sharma
Keyword(s):  
Black Hole ◽  
Cosmological Constant ◽  
Test Particle ◽  
Gravitational Lensing ◽  
Critical Parameters ◽  
Btz Black Hole ◽  
Bending Angle ◽  
Retrograde Motion ◽  
Test Particles ◽  
Dimensional Gravity

We present a detailed study of gravitational lensing around a rotating Bañados–Teitelboim–Zanelli (BTZ) black hole in (2 + 1)-dimensional gravity. The study of orbits for massless test particle around this BH spacetime is performed to describe the nature of cosmological constant in lower dimensions. We study the effect of cosmological constant on the photon orbit in view of other critical parameters. The bending angle of light is studied in view of different values of cosmological constant for direct and retrograde motion of test particles. It is being observed that the bending angle slightly decreases as the value of cosmological constant increases in the negative region.

RENORMALIZATION OF STOCHASTICALLY QUANTIZED FIELD THEORIES

1988 ◽  
Vol 03 (01) ◽  
pp. 163-185 ◽  
Author(s):  
S. CHATURVEDI ◽  
A.K. KAPOOR ◽  
V. SRINIVASAN
Keyword(s):  
Langevin Equation ◽  
Field Theories ◽  
Quantization Scheme ◽  
Stochastic Quantization ◽  
Coupling Constant ◽  
Operator Formalism ◽  
Four Dimensions ◽  
Quantized Field ◽  
The One ◽  
Renormalization Constants

We discuss the renormalizability of stochastically quantized ϕ4 theory in four dimensions using the operator formalism of the Langevin equation developed by Namiki and Yamanaka. The operator formalism casts the Parisi Wu stochastic quantization scheme into a five-dimensional field theory. The usefulness of this approach over the one based directly on the Langevin equation is brought out for discussion of renormalization. We propose a new regularization scheme for the stochastic diagrams and use it to compute the renormalization constants and counter terms for the ϕ4 theory to second order in the coupling constant.

scholarly journals QUANTUM DILATONIC GRAVITY IN d=2,4 AND 5 DIMENSIONS

2001 ◽  
Vol 16 (06) ◽  
pp. 1015-1108 ◽  
Author(s):  
SHIN'ICHI NOJIRI ◽  
SERGEI D. ODINTSOV
Keyword(s):  
Black Hole ◽  
Effective Action ◽  
Gauge Coupling ◽  
Conformal Anomaly ◽  
De Sitter ◽  
Nonzero Temperature ◽  
Four Dimensions ◽  
Yang Mills ◽  
Renormalization Group Equations ◽  
The One

We review (mainly) quantum effects in the theories where the gravity sector is described by metric and dilaton. The one-loop effective action for dilatonic gravity in two and four dimensions is evaluated. Renormalization group equations are constructed. The conformal anomaly and induced effective action for 2d and 4d dilaton coupled theories are found. It is applied to the study of quantum aspects of black hole thermodynamics, like calculation of Hawking radiation and quantum corrections to black hole parameters and investigation of quantum instability for such objects with multiple horizons. The use of the above effective action in the construction of nonsingular cosmological models in Einstein or Brans–Dicke (super)gravity and investigation of induced wormholes in supersymmetric Yang–Mills theory are given.5d dilatonic gravity (bosonic sector of compactified IIB supergravity) is discussed in connection with bulk/boundary (or AdS/CFT) correspondence. Running gauge coupling and quark–antiquark potential for boundary gauge theory at zero or nonzero temperature are calculated from d=5 dilatonic anti-de Sitter-like background solution which represents anti-de Sitter black hole for periodic time.

THOUGHTS ON THE AREA THEOREM

2009 ◽  
Vol 24 (16n17) ◽  
pp. 3111-3135 ◽  
Author(s):  
MU-IN PARK
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Three Dimensional ◽  
Kerr Black Hole ◽  
Second Law Of Thermodynamics ◽  
Positive Energy ◽  
Btz Black Hole ◽  
Area Theorem ◽  
Four Dimensions ◽  
Higher Derivative

Hawking's area theorem can be understood from a quasistationary process in which a black hole accretes positive energy matter, independent of the details of the gravity action. I use this process to study the dynamics of the inner as well as the outer horizons for various black holes which include the recently discovered exotic black holes and three-dimensional black holes in higher derivative gravities as well as the usual Banados–Teitelboim–Zanelli (BTZ) black hole and the Kerr black hole in four dimensions. I find that the area for the inner horizon "can decrease," rather than increase, with the quasistationary process. However, I find that the area for the outer horizon "never decrease" such as the usual area theorem still works in our examples, though this is quite nontrivial in general. I also find that the recently proposed new entropy formulae for the above mentioned, recently discovered black holes satisfy the second law of thermodynamics.

scholarly journals Strong lensing and observables around 5D Myers–Perry black hole spacetime

2018 ◽  
Vol 33 (23) ◽  
pp. 1850126
Author(s):  
Ravi Shankar Kuniyal ◽  
Hemwati Nandan ◽  
Uma Papnoi ◽  
Rashmi Uniyal ◽  
K. D. Purohit
Keyword(s):  
Black Hole ◽  
Deflection Angle ◽  
Strong Field ◽  
Kerr Black Hole ◽  
Four Dimensions ◽  
Test Particles ◽  
Spin Parameter ◽  
Black Hole Spacetime ◽  
Field Coefficient ◽  
Deflection Limit

We study the motion of massless test particles in a five-dimensional (5D) Myers–Perry black hole spacetime with two-spin parameters. The behavior of the effective potential in view of different values of black hole parameters is discussed in the equatorial plane. The frequency shift of photons is calculated which is found to depend on the spin parameter of black hole and the observed redshift is discussed accordingly. The deflection angle and the strong deflection limit coefficients are also calculated and their behavior with the spin parameters is analyzed in detail. It is observed that the behaviors of both deflection angle and strong field coefficient differs from Kerr black hole spacetime in four dimensions in General Relativity (GR), which is mainly due to the presence of two-spin parameters in higher dimension.

scholarly journals STRINGS IN AdS3 AND THE SL(2, R) WZW MODEL

2001 ◽  
Vol 16 (05) ◽  
pp. 677-682
Author(s):  
HIROSI OOGURI
Keyword(s):  
Hilbert Space ◽  
Black Hole ◽  
Partition Function ◽  
Long Strings ◽  
Three Dimensional ◽  
De Sitter Space ◽  
De Sitter ◽  
Btz Black Hole ◽  
Discrete States ◽  
The One

Strings in the three-dimensional anti-de Sitter space in the NS background is described by the SL(2, R) WZW model. We present a complete description of the Hilbert space of the model. We then compute the one-loop partition function for Euclidean BTZ black hole backgrounds or equivalently thermal AdS3 backgrounds which are quotients of Euclidean AdS3. We see long strings and discrete states in agreement with the structure of the Hilbert space.

scholarly journals CAN QUANTUM-CORRECTED BTZ BLACK HOLE ANTI-EVAPORATE?

1998 ◽  
Vol 13 (33) ◽  
pp. 2695-2704 ◽  
Author(s):  
SHIN'ICHI NOJIRI ◽  
SERGEI D. ODINTSOV
Keyword(s):  
Black Hole ◽  
Effective Action ◽  
Quantum Evolution ◽  
S Wave ◽  
Btz Black Hole ◽  
Higher Modes ◽  
Wave Approximation ◽  
Large N ◽  
The One ◽  
Kaluza Klein

Kaluza–Klein reduction of 3-D gravity with minimal scalars leads to 2-D dilaton-Maxwell gravity with dilaton coupled scalars. Evaluating the one-loop effective action for dilaton coupled scalars in large-N and s-wave approximation, we apply it to study quantum evolution of BTZ black hole. It is shown that quantum-corrected BTZ BH may evaporate or else anti-evaporate which is similar to 4-D Nariai BH as is observed by Bousso and Hawking. Instable higher modes in the spectrum also indicate the possibility of proliferation of BTZ BH.

scholarly journals $$T\bar{T}$$ deformation of chiral bosons and Chern–Simons $$\hbox {AdS}_3$$ gravity

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Hao Ouyang ◽  
Hongfei Shu
Keyword(s):  
Black Hole ◽  
Scalar Fields ◽  
Flow Equation ◽  
Energy Tensor ◽  
Stress Energy Tensor ◽  
Btz Black Hole ◽  
Stress Energy ◽  
The One ◽  
Chiral Bosons ◽  
Chern Simons

AbstractWe study the $$T\bar{T}$$ T T ¯ deformation of the chiral bosons and show the equivalence between the chiral bosons of opposite chiralities and the scalar fields at the Hamiltonian level under the deformation. We also derive the deformed Lagrangian of more generic theories which contain an arbitrary number of chiral bosons to all orders. By using these results, we derive the $$T\bar{T}$$ T T ¯ deformed boundary action of the $$\hbox {AdS}_3$$ AdS 3 gravity theory in the Chern–Simons formulation. We compute the deformed one-loop torus partition function, which satisfies the $$T\bar{T}$$ T T ¯ flow equation up to the one-loop order. Finally, we calculate the deformed stress–energy tensor of a solution describing a BTZ black hole in the boundary theory, which coincides with the boundary stress–energy tensor derived from the BTZ black hole with a finite cutoff.

scholarly journals DYONIC BLACK HOLES WITH STRING-LOOP CORRECTIONS

2003 ◽  
Vol 18 (11) ◽  
pp. 1903-1933
Author(s):  
MIKHAIL Z. IOFA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Black Hole Solution ◽  
Low Energy ◽  
Tree Level ◽  
Coupling Constant ◽  
Heterotic String Theory ◽  
Four Dimensions ◽  
First Order ◽  
String Loop

In heterotic string theory compactified to four dimensions with N = 2 supersymmetry, string-loop corrections to the universal sector of the low-energy effective action are studied. Within the framework of N = 2 supersymmetric formulation of the theory, in the first order in string coupling constant, we solve the system of the loop-corrected Maxwell and Killing spinor equations. Taking as the input the tree-level dyonic black hole solution, we calculate string-loop corrections to the string tree-level metric and moduli of dyonic black hole.

Sign in / Sign up

Export Citation Format

Share Document