Relativistic quantum fluid with boost invariance

TL;DR

This paper investigates a relativistic quantum fluid with boost invariance, providing exact quantum calculations of the stress-energy tensor and entropy current, revealing quantum corrections to classical behavior.

Contribution

It offers a solvable quantum-statistical model of a relativistic fluid with boost invariance, including exact quantum expressions for key physical quantities.

Findings

Finite stress-energy tensor requires vacuum subtraction at fixed proper time

Quantum corrections modify classical free-streaming behavior

Exact expectation values of stress-energy tensor and entropy current obtained

Abstract

We study a relativistic fluid with longitudinal boost invariance in a quantum-statistical framework as an example of a solvable non-equilibrium problem. For the free quantum field, we calculate the exact form of the expectation values of the stress-energy tensor and the entropy current. For the stress-energy tensor, we find that a finite value can be obtained only by subtracting the vacuum of the density operator at some fixed proper time \tau_0. As a consequence, the stress-energy tensor acquires non-trivial quantum corrections to the classical free-streaming form.