Particle Creation and Entanglement in Dispersive Model with Step Velocity Profile

TL;DR

This paper analyzes particle creation and entanglement in a dispersive scalar field model with a step velocity profile, revealing how dispersion affects thermal properties and horizon-related phenomena.

Contribution

It provides exact mode solutions and power spectra calculations for both subsonic and transsonic flows, highlighting the impact of non-linear dispersion on thermal behavior.

Findings

Thermal spectrum appears in transsonic flow near the sonic horizon.

Effective group velocity horizon induces approximate thermal spectrum in subsonic flow.

High-frequency cutoff modifies the thermal distribution of created particles.

Abstract

We investigate particle creation and entanglement structure in a dispersive model with subliminal dispersion relation. Assuming the step function spatial velocity profile of the background flow, mode functions for a massless scalar field is exactly obtained by the matching method. Power spectrums of created particles are calculated for the subsonic and the transsonic flow cases. For the transsonic case, the sonic horizon exists and created particles show the Planckian distribution for low frequency region but the thermal property disappears for high frequency region near the cutoff frequency introduced by the non-linear dispersion. For the subsonic case, although the sonic horizon does not exist, the effective group velocity horizon appears due to the non-linear dispersion for high frequency region and approximate thermal property of the power spectrum arises. Relation between particle creation and entanglement between each mode is also discussed.