There and Back Again: Quantum Radiation from Round-trip Flying Mirrors

TL;DR

This paper investigates quantum radiation emitted by a round-trip flying mirror, revealing complex spectra and symmetries, and challenging the assumption that thermal distributions fully describe the quantum field's spin statistics.

Contribution

It provides the first exact solution for particle creation from a round-trip flying mirror with asymptotic start and stop points, uncovering new spectral features and symmetries.

Findings

Spectra exhibit unique symmetries and time dependence.

Thermal Bogolubov distribution does not match the spin statistics.

Fourier analysis links particle creation to Bogolubov coefficients.

Abstract

Erasing a black hole leaves spacetime flat, so light passing through the region before any star forms and after black hole's evaporation shows no time delay, just like a flying mirror that returns to its initial starting point. Quantum radiation from a round-trip flying mirror has not been solved despite the model's mathematical simplicity and physical clarity. Here, we solve the particle creation from worldlines that asymptotically start and stop at the same spot, resulting in interesting spectra and symmetries, including the time dependence of thermal radiance associated with Bose-Einstein and Fermi-Dirac Bogolubov coefficients. Fourier analysis, intrinsically linked to the Bogolubov mechanism, shows that a thermal Bogolubov distribution does not describe the spin statistics of the quantum field.