子系统状态的兼容性
Compatibility of subsystem states
摘要：
我们研究了比特或量子比特系统的子系统的可能状态。在经典的情况下（位），这意味着可能的边际分布的概率分布在有限数量的二进制变量;我们给出了必要和充分条件的一组概率分布的所有适当子集的变量是边际的一个单一的分布在整个集。在量子情况下（量子比特），我们考虑一组量子比特的子集的混合态;在三个量子比特的情况下，我们发现量子贝尔不等式-一组两个量子比特的状态是三个量子比特的单个混合态的简化状态的必要条件。我们猜想这些条件也是充分的。
英文摘要：
We examine the possible states of subsystems of a system of bits or qubits. In the classical case (bits), this means the possible marginal distributions of a probability distribution on a finite number of binary variables; we give necessary and sufficient conditions for a set of probability distributions on all proper subsets of the variables to be the marginals of a single distribution on the full set. In the quantum case (qubits), we consider mixed states of subsets of a set of qubits; in the case of three qubits, we find quantum Bell inequalities -- necessary conditions for a set of two-qubit states to be the reduced states of a single mixed state of three qubits. We conjecture that these conditions are also sufficient.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
