Quantum entanglement in phase space

TL;DR

This paper introduces new entanglement detection criteria based on Wigner function measurements, offering practical advantages for continuous variable quantum systems where quadrature measurements are challenging.

Contribution

The authors develop tight entanglement criteria from Wigner function measurements, applicable to Gaussian and non-Gaussian states, expanding detection methods in continuous variable quantum systems.

Findings

Criteria are tight for various Gaussian states

Criteria are effective for non-Gaussian states

Provides practical tools for experimental entanglement detection

Abstract

While commonly used entanglement criteria for continuous variable systems are based on quadrature measurements, here we study entanglement detection from measurements of the Wigner function. These are routinely performed in platforms such as trapped ions and circuit QED, where homodyne measurements are difficult to be implemented. We provide complementary criteria which we show to be tight for a variety of experimentally relevant Gaussian and non-Gaussian states. Our results show novel approaches to detect entanglement in continuous variable systems and shed light on interesting connections between known criteria and the Wigner function.