Bipartite Mixed States of Infinite-Dimensional Systems are Generically Nonseparable

Non-local Correlations are Generic in Infinite-Dimensional Bipartite Systems

It was recently shown that the nonseparable density operators for a bipartite system are trace norm dense if either factor space has infinite dimension. We show here that non-local states -- i.e., states whose correlations cannot be reproduced by any local hidden variable model -- are also dense. Our constructions distinguish between the cases where both factor spaces are infinite-dimensional, where we show that states violating the CHSH inequality are dense, and the case where only one factor space is infinite-dimensional, where we identify open neighborhoods of nonseparable states that do no…

偏 Von Neumann 熵的归约诱导变分

Entanglement as Difference: Reduction-induced Minimal Partial Entropy Difference

针对二部混合态量子纠缠度量计算复杂或适用受限的问题，提出偏Von Neumann熵的归约诱导变分方法，实现任意二部态纠缠的直观量化与简便计算，并通过对比验证其优越性。

大部件在所有切割中普遍具有纠缠性

Large Parts are Generically Entangled Across All Cuts

研究证明了大部件在所有切割中普遍具有纠缠性，并展示了纠缠转置性在多体封闭系统中的普遍特征。

Bound entanglement for continuous variables is a rare phenomenon

We discuss the notion of bound entanglement (BE) for continuous variables (CV). We show that the set of non--distillable states (NDS) for CV is nowhere dense in the set of all states, i.e., the states of infinite--dimensional bipartite systems are generically distillable. This automatically implies that the sets of separable states, entangled states with positive partial transpose, and bound entangled states are also nowhere dense in the set of all states. All these properties significantly distinguish quantum CV systems from the spin like ones. The aspects of the definition of BE for CV is al…

Out-of-equilibrium Correlated Systems : Bipartite Entanglement as a Probe of Thermalization

Thermalization play a central role in out-of-equilibrium physics of ultracold atoms or electronic transport phenomena. On the other hand, entanglement concepts have proven to be extremely useful to investigate quantum phases of matter. Here, it is argued that **bipartite** entanglement measures provide key information on out-of-equilibrium states and might therefore offer stringent thermalization criteria. This is illustrated by considering a global quench in an (extended) XXZ spin-1/2 chain across its (zero-temperature) quantum critical point. A non-local **bipartition** of the chain **preser…