Scalar, spinor, and photon fields under relativistic cavity motion

TL;DR

This paper investigates the behavior of scalar, spinor, and photon quantum fields in a relativistically accelerated cavity, revealing how boundary conditions and acceleration profiles affect unitarity and mode mixing, with implications for relativistic quantum information.

Contribution

It introduces a perturbative formalism for analyzing quantum fields in relativistically accelerated cavities, extending previous scalar field studies to photons and spinors with various boundary conditions.

Findings

Unitarity holds for smooth accelerations but fails for discontinuous ones in higher dimensions.

Photon fields decompose into Dirichlet-like and Neumann-like polarizations.

The mode-mixing scenario applies to photon fields, extending previous scalar field results.

Abstract

We analyse quantised scalar, spinor and photon fields in a mechanically rigid cavity that is accelerated in Minkowski spacetime, in a recently-introduced perturbative small acceleration formalism that allows the velocities to become relativistic, with a view to applications in relativistic quantum information. A scalar field is analysed with both Dirichlet and Neumann boundary conditions, and a photon field under perfect conductor boundary conditions is shown to decompose into Dirichlet-like and Neumann-like polarisation modes. The Dirac spinor is analysed with a nonvanishing mass and with dimensions transverse to the acceleration, and the MIT bag boundary condition is shown to exclude zero modes. Unitarity of time evolution holds for smooth accelerations but fails for discontinuous accelerations in spacetime dimensions (3+1) and higher. As an application, the experimental desktop mode-mixing scenario proposed for a scalar field by Bruschi et al. [New J. Phys. 15, 073052 (2013)] is shown to apply also to the photon field.