Indefinite causal order enables perfect quantum communication with zero capacity channels
Indefinite causal order enables perfect quantum communication with zero capacity channels
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DOI：
10.1088/1367-2630/abe7a0
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发表时间：
2021-03-01
影响因子：
3.3
通讯作者：
Kar, Guruprasad
中科院分区：
文献类型：
--
作者：
Chiribella, Giulio;Banik, Manik;Kar, Guruprasad
量子力学与两个事件之间的相对顺序可以是不确定的情况是兼容的。在这里，我们表明，噪声过程的两个独立的实例可以表现为一个完美的量子通信信道时，在两个替代订单的相干叠加使用。即使原始过程传输量子信息的能力为零，这种现象也会发生。与此相反，当信息直接从发送者通过不同路径的叠加发送到接收者，每条路径上都有独立的噪声过程时，就不会发生完美的量子通信。通过独立的噪声信道进行完美量子通信的可能性突出了时间上的顺序叠加和空间上的路径叠加之间的根本区别。
Quantum mechanics is compatible with scenarios where the relative order between two events can be indefinite. Here we show that two independent instances of a noisy process can behave as a perfect quantum communication channel when used in a coherent superposition of two alternative orders. This phenomenon occurs even if the original process has zero capacity to transmit quantum information. In contrast, perfect quantum communication does not occur when the message is sent directly from the sender to the receiver through a superposition of alternative paths, with an independent noise process acting on each path. The possibility of perfect quantum communication through independent noisy channels highlights a fundamental difference between the superposition of orders in time and the superposition of paths in space.