arXiv subjects

Johannes Noll

Publications and source records attributed to Johannes Noll.

3 recordsLinked to original sources

arXiv2024

Optimizing detection of continuous variable entanglement for limited data

We explore the advantages of a class of entanglement criteria for continuous variable systems based on the Husimi $Q$-distribution in scenarios with sparse experimental data. The generality of these criteria allows optimizing them for a given entangled state and experimental setting. We consider the scenario of coarse grained measurements, or finite detector resolution, where the values of the Husimi $Q$-distribution are only known on a grid of points in phase space, and show how the entanglement criteria can be adapted to this case. Further, we examine the scenario where experimental measurements amount to drawing independent samples from the Husimi distribution. Here, we customize our entanglement criteria to maximize the statistical significance of the detection for a given finite number of samples. In both scenarios optimization leads to clear improvements enlarging the class of detected states and the signal-to-noise ratio of the detection, respectively.

quant-ph↗

arXiv2024

Detecting continuous variable entanglement in phase space with the $Q$-distribution

We prove a general class of continuous variable entanglement criteria based on the Husimi $Q$-distribution, which represents a quantum state in canonical phase space, by employing a theorem by Lieb and Solovej. We discuss their generality, which roots in the possibility to optimize over the set of concave functions, from the perspective of continuous majorization theory and show that with this approach families of entropic as well as second moment criteria follow as special cases. All derived criteria are compared to corresponding marginal based criteria and the strength of the phase space approach is demonstrated for a family of prototypical example states where only our criteria flag entanglement. Further, we explore their optimization prospects in two experimentally relevant scenarios characterized by sparse data: finite detector resolution and finite statistics. In both scenarios optimization leads to clear improvements enlarging the class of detected states and the signal-to-noise ratio of the detection, respectively.

quant-ph↗

arXiv2024

General class of continuous variable entanglement criteria

We present a general class of entanglement criteria for continuous variable systems. Our criteria are based on the Husimi $Q$-distribution and allow for optimization over the set of all concave functions rendering them extremely general and versatile. We show that several entropic criteria and second moment criteria are obtained as special cases. Our criteria reveal entanglement of families of states undetected by any commonly used criteria and provide clear advantages under typical experimental constraints such as finite detector resolution and measurement statistics.

quant-ph↗