Mode-Invisibility as a non-Destructive Probe of Entangled QUBIT-CAT States

TL;DR

This paper introduces a non-destructive method using mode invisibility to measure properties of a qubit entangled with a generalized CAT state, including amplitude, position, and entanglement entropy, via a quantum probe.

Contribution

It presents a novel application of mode invisibility for non-destructive measurement of entangled qubit-cat states, linking entropy to phase shifts for experimental access.

Findings

Successfully measures coherent state amplitude and qubit position non-destructively

Establishes a connection between von Neumann entropy and phase shift

Demonstrates potential for experimental entanglement measurement

Abstract

We investigate the dynamics for a two level atomic system entangled to coherent states using the recently developed mode invisibility technique. Using a quantum 2-level probe, we demonstrate a way to non-destructively measure a number of properties between a qubit entangled with a generalized CAT state, including the amplitude of the coherent state, the location and relative excitation of the qubit, and the von Neumann entropy. Our results indicate a connection between this last quantity and the interferometric phase shift of the probe, thereby suggesting a possible way to experimentally measure entanglement non-destructively.