A truncated photon

TL;DR

This paper explores the concept of truncating a photon with an optical shutter, resulting in a complex superposition state that challenges traditional notions of photon indivisibility and has implications for quantum field theory.

Contribution

It introduces the concept of a truncated photon state, demonstrating its properties and potential usefulness in understanding locality and equivalence in quantum field theory.

Findings

Truncated photon states are superpositions of photon numbers up to infinity.

Such states are locally equivalent to single photons or vacuum in disjoint regions.

The work provides insights into locality and equivalence in quantum field theory.

Abstract

An elementary particle such as a photon cannot be cut in two pieces. Still it must be possible to truncate a photon with an optical shutter. The result is not another photon or a mix of a photon and a vacuum. Instead it is a superposition and mix of photon numbers up to infinity. This state is rather complicated, but nevertheless locally equivalent to a single photon or vacuum in disjoint regions. Finally we demonstrate how the truncated photon may be illuminating and useful for the understanding of locality and equivalence in quantum field theory.