Beam splitter as quantum coherence-maker

TL;DR

This paper investigates how a beam splitter can generate quantum coherence, identifying optimal conditions and states, notably two-mode squeezed vacuum, that maximize coherence gain.

Contribution

It provides a quantitative analysis of coherence generation by beam splitters, highlighting optimal input states and parameters for maximum coherence gain.

Findings

Two-mode squeezed vacuum yields the highest coherence gain.

Optimal input states and beam splitter parameters maximize coherence production.

Results are consistent across different coherence measures.

Abstract

The aim of this work is to answer the question of how much quantum coherence a beam splitter is able to produce. To this end we consider as the variables under study both the amount of coherence of the input states as well as the beam splitter characteristics. We conclude that there is an optimal combination of these factors making the gain of coherence maximum. In addition, the two mode squeezed vacuum arises as the studied state most capable of gaining coherence when passing through a beam splitter. These results are qualitatively equivalent for the the l1-norm of coherence and for the relative entropy of coherence.