Negative Energy in Superposition and Entangled States

TL;DR

This paper investigates the maximum negative energy density achievable in quantum states of a massless scalar field, analyzing superposition and entangled states relevant to quantum optics experiments.

Contribution

It provides a systematic calculation of negative energy density limits in specific quantum states, highlighting potential experimental realizations.

Findings

Maximum negative energy density quantified for superposition and entangled states.

Parameters for states with negative energy density derived and analyzed.

Potential for experimental generation of states with negative energy explored.

Abstract

We examine the maximum negative energy density which can be attained in various quantum states of a massless scalar field. We consider states in which either one or two modes are excited, and show that the energy density can be given in terms of a small number of parameters. We calculate these parameters for several examples of superposition states for one mode, and entangled states for two modes, and find the maximum magnitude of the negative energy density in these states. We consider several states which have been, or potentially will be, generated in quantum optics experiments.