Barnum Howard, Knill Emanuel, Ortiz Gerardo, Somma Rolando, Viola Lorenza
Los Alamos National Laboratory, MS B256, Los Alamos, New Mexico 87545, USA.
Phys Rev Lett. 2004 Mar 12;92(10):107902. doi: 10.1103/PhysRevLett.92.107902.
We present a generalization of entanglement based on the idea that entanglement is relative to a distinguished subspace of observables rather than a distinguished subsystem decomposition. A pure quantum state is entangled relative to such a subspace if its expectations are a proper mixture of those of other states. Many information-theoretic aspects of entanglement can be extended to this observable-based setting, suggesting new ways of measuring and classifying multipartite entanglement. By going beyond the distinguishable-subsystem framework, generalized entanglement also provides novel tools for probing quantum correlations in interacting many-body systems.
我们基于纠缠相对于可观测量的一个特殊子空间而非一个特殊子系统分解这一观点，提出了纠缠的一种推广。如果一个纯量子态的期望值是其他态的期望值的恰当混合，那么它相对于这样一个子空间就是纠缠的。纠缠的许多信息理论方面都可以扩展到这种基于可观测量的情形，这暗示了测量和分类多体纠缠的新方法。通过超越可区分子系统框架，广义纠缠还为探测相互作用多体系统中的量子关联提供了新颖的工具。
