arXiv subjects

Mandas Biswas

Publications and source records attributed to Mandas Biswas.

3 recordsLinked to original sources

arXiv2026

(De)Coherence of a quantum system in an anti-de Sitter spacetime

In this paper, we study the coherence/decoherence of a quantum harmonic oscillator in anti-de Sitter (AdS) spacetime by quantising the graviton in a curved background with a nontrivial boundary condition. In the quantum-field-theory framework, we obtain a master equation by tracing away the gravitational field at the leading order in G and 1/omega^2, where omega is related to the trapped frequency of the harmonic oscillator. We will proceed with a semi-Markovian analysis to compute the Lindbladian equation and estimate the decoherence rate and selection rules at the leading order, which come in two kinds: one responsible for the local interaction between matter and graviton, and the other related to the AdS global curvature. The latter determines the recoherence of the quantum system for a certain choice of the trapped harmonic oscillator's frequency and the global curvature. We also demonstrate that we recover the flat spacetime limit by taking appropriate approximations.

hep-th↗

arXiv2026

The No-Short Hair Theorem for Black Holes and Wormholes in Extra-Dimension

The no-short hair theorem for static spherically symmetric black holes in general theory of relativity asserts that if a black hole has hair, that hair must extend beyond the lowest photon sphere radius of the black hole. This report generalizes the theorem to various extra-dimensional cases of black holes and wormholes in post-Einstein gravity and shows how the observational satisfaction of the no-short hair theorem may lead to a probe for the existence of extra-dimensions. We also show how we may lead to argue that this no-short hair theorem is satisfied for black holes in theories of quantum gravity that naturally precludes extra-dimensional cases, like string theory.

gr-qc↗

arXiv2024

Quantum-Classical Correspondence in a Quartic Oscillator -- Corrections to Frequency and Bounds for Periodic Motion

We take a qualitative comparative look at quantum and classical quartic anharmonic oscillators. It has been shown that the behavior of the quantum anharmonic oscillator mimics that of the classical anharmonic oscillators with the structurally same Hamiltonian in the coherent state basis of the harmonic oscillators. The associated equation of motion allows us to use Lindstet-Poincare perturbation method to compute the classical frequency of the oscillation order by order, by taking care of its dependence on amplitude and the quantum corrections. We also derive a bound for periodicity of such oscillations in both the classical and quantum cases.

quant-ph↗