Quantum Non-Demolition Detection of Strongly Correlated Systems

TL;DR

This paper introduces a quantum non-demolition method for detecting strongly correlated states in ultracold atoms, enabling minimally invasive measurements of complex quantum orders via light-matter interactions.

Contribution

It presents a novel technique that maps atomic quantum correlations onto light polarization, allowing efficient, spatially resolved detection of various quantum phases in many-body systems.

Findings

Successfully detects antiferromagnetic order in lattice systems.

Demonstrates potential for observing superfluid order in Fermi liquids.

Provides a minimally destructive measurement approach for quantum many-body states.

Abstract

Preparation, manipulation, and detection of strongly correlated states of quantum many body systems are among the most important goals and challenges of modern physics. Ultracold atoms offer an unprecedented playground for realization of these goals. Here we show how strongly correlated states of ultracold atoms can be detected in a quantum non-demolition scheme, that is, in the fundamentally least destructive way permitted by quantum mechanics. In our method, spatially resolved components of atomic spins couple to quantum polarization degrees of freedom of light. In this way quantum correlations of matter are faithfully mapped on those of light; the latter can then be efficiently measured using homodyne detection. We illustrate the power of such spatially resolved quantum noise limited polarization measurement by applying it to detect various standard and "exotic" types of antiferromagnetic order in lattice systems and by indicating the feasibility of detection of superfluid order in Fermi liquids.