arXiv subjects

Prasad Basu

Publications and source records attributed to Prasad Basu.

5 recordsLinked to original sources

arXiv2023

Ideal E/IMRI vs Real E/IMRI system : Observable signature in LISA

Real extreme/intermediate mass ratio inspiral(E/IMRI) systems are likely to contain large accretion disks which could be as massive as the central supermassive black hole. Therefore, contrary to its ideal model, a real E/IMRI system contains a third important component: the accretion disk. We study the influence of these disks on the emitted GW profile and its detectability through proposed LISA observation. We use a semi-relativistic formalism in the Kerr background (Gair & Glampedakis 2006; Barausse & Rezzolla 2008) for the case of transonic accretion flow which is a potential candidate to describe the accretion flows around AGN. The hydrodynamic drag of the disks modified the motion of the companion as a result the emitted wave changes in amplitude and phase. We found that these changes are detectable through the last few years of observation by LISA (in some cases as small as six months) for EMRIs residing within 3 GPc from the detector and for the accretion rate of the primary black hole of the order of $\dot{M}=1 \dot{M}_{Edd}$. These choices of parameter values are consistent with real systems. The drag effect and hence the detectability of the emitted GW is sensitive to the hydrodynamical model of the disk. Therefore such observations will help one to identify the nature of the accretion flow and verify various paradigms of accretion physics.

astro-ph.HE↗

arXiv2011

4-Velocity distribution function using Maxwell-Boltzmann's original approach and a new form of the relativistic equation of state

Following the original approach of Maxwell-Boltzmann(MB), we derive a 4-velocity distribution function for the relativistic ideal gas. This distribution function perfectly reduces to original MB distribution in the non-relativistic limit. We express the relativistic equation of state(EOS), $ρ-ρ_0=(γ-1)^{-1}p$,\ in the two equations: $ρ=ρ_0 f(λ)$,\ and $p=ρ_0 g(λ)$, where $λ$\ is a parameter related to the kinetic energy, hence the temperature, of the gas. In the both extreme limits, they give correct EOS:\ $ρ=3p$\ in the ultra-relativistic, and\ $ρ-ρ_0=3/2p$ in the non-relativistic regime. Using these equations the adiabatic index $γ$ (=$\frac{c_p}{c_v}$) and the sound speed $a_s$ are calculated as a function of $λ$. They also satisfy the inequalities: $4/3 \le γ\le 5/3$ and $a_s \le \frac{1}{\sqrt{3}}$ perfectly.

astro-ph.SR↗

arXiv2011

A unifying perspective on the Moyal and Voros products and their physical meanings

The Moyal and Voros formulations of non-commutative quantum field theory has been a point of controversy in the recent past. Here we address this issue in the context of non-commutative non-relativistic quantum mechanics. In particular we show that the two formulations simply correspond to two different representations associated with two different choices of basis on the quantum Hilbert space. From a mathematical perspective the two formulations are therefore completely equivalent, but we also argue that only the Voros formulaton admits a consistent physical interpretation. These considerations are elucidated by considering the free particle transition amplitude in the two representations.

hep-th↗

arXiv2010

Fate of the Superconducting Ground State on the Moyal Plane

It is known that Berry curvature of the band structure of certain crystals can lead to effective noncommutativity between spatial coordinates. Using the techniques of twisted quantum field theory, we investigate the question of the formation of a paired state of twisted fermions in such a system. We find that to leading order in the noncommutativity parameter, the gap between the non-interacting ground state and the paired state is {\it smaller} compared to its commutative counterpart. This suggests that BCS type superconductivity, if present in such systems, is more fragile and easier to disrupt.

hep-th↗

arXiv2010

Thermal Correlation Functions of Twisted Quantum Fields

We derive the thermal correlators for twisted quantum fields on noncommutative spacetime. We show that the thermal expectation value of the number operator is same as in commutative spacetime, but that higher correlators are sensitive to the noncommutativity parameters $θ^{μν}$.

hep-th↗