Piani Marco, Horodecki Paweł, Horodecki Ryszard
Institut für Theoretische Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
Phys Rev Lett. 2008 Mar 7;100(9):090502. doi: 10.1103/PhysRevLett.100.090502. Epub 2008 Mar 6.
We prove that the correlations present in a multipartite quantum state have an operational quantum character even if the state is unentangled, as long as it does not simply encode a multipartite classical probability distribution. Said quantumness is revealed by the new task of local broadcasting, i.e., of locally sharing preestablished correlations, which is feasible if and only if correlations are stricly classical. Our operational approach leads to natural definitions of measures for quantumness of correlations. It also reproduces the standard no-broadcasting theorem as a special case.
我们证明，即使多体量子态是可分离的，只要它不是简单地编码一个多体经典概率分布，那么该量子态中存在的关联就具有可操作的量子特性。这种量子特性可通过局部广播这一新任务来揭示，即局部共享预先建立的关联，当且仅当关联严格为经典时，该任务才可行。我们的操作方法得出了关联量子特性度量的自然定义。它还在特殊情况下重现了标准的不可广播定理。
