Cost of quantum entanglement simplified
Cost of quantum entanglement simplified
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DOI：
10.1103/physrevlett.125.040502
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发表时间：
2020-07
影响因子：
8.6
通讯作者：
Xin Wang;M. Wilde
中科院分区：
文献类型：
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作者：
Xin Wang;M. Wilde
量子纠缠是量子信息处理中的关键物理资源，允许执行基本的量子任务，如隐形传态和量子密钥分配，这在经典世界中是不可能的。自量子信息论兴起以来，如何对量子纠缠进行信息论意义上的量化一直是一个悬而未决的问题。特别是，每个先前定义的纠缠度量承载精确的信息论意义是不知道是有效的可计算的，或者如果它是有效的可计算的，那么它是不知道有一个精确的信息论意义。在这封信中，我们通过引入一种纠缠度量来应对这一挑战，这种纠缠度量具有精确的信息论意义，即当两个遥远的方被允许执行完全保持部分转置的正性的量子操作时，准备纠缠态所需的确切成本。此外，这种纠缠度量可以通过半定规划有效地计算，并且具有一些有用的性质，如可加性和忠实性。我们的结果为任意量子态的基本纠缠结构带来了关键的见解，它们可以直接用于评估和量化量子物理实验中产生的纠缠。
Quantum entanglement is a key physical resource in quantum information processing that allows for performing basic quantum tasks such as teleportation and quantum key distribution, which are impossible in the classical world. Ever since the rise of quantum information theory, it has been an open problem to quantify entanglement in an information-theoretically meaningful way. In particular, every previously defined entanglement measure bearing a precise information-theoretic meaning is not known to be efficiently computable, or if it is efficiently computable, then it is not known to have a precise information-theoretic meaning. In this Letter, we meet this challenge by introducing an entanglement measure that has a precise information-theoretic meaning as the exact cost required to prepare an entangled state when two distant parties are allowed to perform quantum operations that completely preserve the positivity of the partial transpose. Additionally, this entanglement measure is efficiently computable by means of a semidefinite program, and it bears a number of useful properties such as additivity and faithfulness. Our results bring key insights into the fundamental entanglement structure of arbitrary quantum states, and they can be used directly to assess and quantify the entanglement produced in quantum-physical experiments.