Multimode coherent states and the Lorentz-invariant mass of light pulses

TL;DR

This paper defines and calculates the Lorentz-invariant mass of diverging light pulses composed of noncollinear photons, using both classical and quantum approaches, with quantum derivation based on multimode coherent states.

Contribution

It introduces a quantum derivation of the light pulse mass using multimode coherent states, connecting quantum parameters to classical field properties.

Findings

Explicit expression for the mass of diverging light pulses

Quantum and classical derivations are consistent

Links between quantum state parameters and classical fields established

Abstract

The total mass of noncollinear photons forming diverging light pulses is defined and found explicitly. Both classical and quantum derivations are presented. The quantum derivation is based on the use of multimode coherent states, and links between parameters of these states and those of the classical field strength are established.