Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, Ontario N2L 2Y5, Canada.
Phys Rev Lett. 2012 Sep 14;109(11):110501. doi: 10.1103/PhysRevLett.109.110501. Epub 2012 Sep 12.
The communication complexity of a quantum channel is the minimal amount of classical communication required for classically simulating a process of state preparation, transmission through the channel and subsequent measurement. It establishes a limit on the power of quantum communication in terms of classical resources. We show that classical simulations employing a finite amount of communication can be derived from a special class of hidden variable theories where quantum states represent statistical knowledge about the classical state and not an element of reality. This special class has attracted strong interest very recently. The communication cost of each derived simulation is given by the mutual information between the quantum state and the classical state of the parent hidden variable theory. Finally, we find that the communication complexity for single qubits is smaller than 1.28 bits. The previous known upper bound was 1.85 bits.
量子通道的通信复杂度是经典模拟状态准备、通过通道传输和随后测量过程所需的最少经典通信量。它以经典资源为单位限制了量子通信的能力。我们表明，可以从一类特殊的隐变量理论中推导出使用有限数量通信的经典模拟，其中量子态表示关于经典态的统计知识，而不是现实的一个要素。最近，这个特殊的类吸引了强烈的兴趣。每个衍生模拟的通信成本由量子态和父隐变量理论的经典状态之间的互信息给出。最后，我们发现单量子位的通信复杂度小于 1.28 位。之前已知的上界是 1.85 位。
