Duality in asymmetric Quantum optical Ramsey interferometers

TL;DR

This paper applies a recent formalism to a quantum optical Ramsey interferometer to distinguish between classical predictability and quantum which-way information, revealing that quantum information can be quantified even when total distinguishability is low.

Contribution

It demonstrates how to separate and quantify classical and quantum sources of which-way information in a quantum optical interferometer using a new formalism.

Findings

The formalism effectively separates predictability and quantum information sources.

Quantum 'Quality' Q can quantify which-way information even when total distinguishability D is low.

The approach enhances understanding of quantum measurement and information in interferometric setups.

Abstract

A formalism have been recently derived [J. Martinez-Linares and D. Harmin, quantum-ph/0306057] allowing one to separate different sources of which-way information contributing to the total distinguishability D of the ways in a two-way interferometer. Here we apply the formalism to a Quantum Optical Ramsey Interferometer where both sources, the a-priori predictability of the ways P and the quantum "Quality" Q of the which-way detector, stems from the same physical interaction. We show that the formalism is able to separate both sources of which-way information. Moreover, it is shown that Q succeeds in quantifying the amount of quantum which-way information stored in the which-way detector even in cases where D does not.