arXiv subjects

Abhinove Nagarajan Seenivasan

Publications and source records attributed to Abhinove Nagarajan Seenivasan.

4 recordsLinked to original sources

arXiv2024

Hydrodynamics of $(1+1)$ dimensional fluid in the presence of gravitational anomaly from first order thermodynamics

Considering ($1+1$)-dimensional fluid in presence of gravitational trace anomaly, as an effective description of higher-dimensional fluid, the hydrodynamics is discussed through a first order thermodynamic description. Contrary to the existing approaches which are second order in nature, the fluid velocity is identified through the auxiliary field required to describe the Polyakov action for the effective description of relevant energy-momentum tensor. The thermodynamic and fluid quantities, on a static black hole spacetime, are calculated both near the horizon as well as at the asymptotic infinity. The Unruh vacuum appears to be suitable one for the present analysis, in contrast to Israel-Hartle-Hawking vacuum which is consistent with second order description. As in anomaly cancellation approach to find the Hawking flux the Unruh vacuum is consistent with the required conditions, in reverse way we interpret this fluid description as an alternative approach to find these required conditions to calculate the same in anomaly cancellation approach.

gr-qc↗

arXiv2023

Probing the curvature of the cosmos from quantum entanglement due to gravity

If gravity is fundamentally quantum, any two quantum particles must get entangled with each other due to their mutual interaction through gravity. This phenomenon, dubbed gravity-mediated entanglement, has led to recent efforts of detecting perturbative quantum gravity in table-top experimental setups. In this paper, we generalize this to imagine two idealized massive oscillators, in their ground state, which get entangled due to gravity in an expanding universe, and find that the curvature of the background spacetime leaves its imprints on the resulting entanglement profile. Thus, detecting gravity-mediated entanglement from cosmological observations will open up an exciting new avenue of measuring the local expansion rate of the cosmos.

gr-qc↗

arXiv2023

Gravity-induced entanglement as a probe of spacetime curvature

It is now widely believed that if the gravitational field is (perturbatively) quantum, it would entangle two massive objects (in spatial superpositions) which were otherwise unentangled to begin with. Recently, actual table-top experiments have been proposed to test this idea in what would be the first detection of perturbative quantum gravity. In this essay, we devise a thought experiment to prove that such gravity-induced entanglement depends on the spacetime curvature and can, in principle, act as an alternate signature of the expanding background. This will open up new and complementary directions to search for such entanglement in curved spacetime and reveal fresh perspectives on it.

gr-qc↗

arXiv2023

Scalar fluid in scalar-tensor gravity from an equivalent picture of thermodynamic and fluid descriptions of gravitational dynamics

We revisit the thermodynamic description of fluid, represented by scalar field in scalar-tensor gravity theory through a general approach to study the thermodynamics of relativistic fluids. In order to identify the fluid energy-momentum tensor, contrary to the existing way, we use equivalent description of gravitational dynamics both in Jordan and Einstein frames as thermodynamical identity and fluid equation on a generic null surface. Such an approach provides the energy-momentum tensors for scalar fluid as that of an ideal fluid in both the frames. We then mention few issues in the existing way of using Eckart's formalism for an ideal fluid. Our investigation suggests that the Eckart's frame may not be suitable to consider ideal fluid. Consequently a possible alternative description, valid in other than Eckart's frame, is being suggested for a general ideal fluid. Based on this we obtain a unified thermodynamic description in both Jordan and Einstein frames from our identified energy-momentum tensors. Finally, the relations between thermodynamic entities on different frames are being put forwarded. Thus, the description in either of the frames is enough to provide the complete picture.

gr-qc↗