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arXiv 1301.3452quant-phcs.ITmath.IT
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量子通信弱与强经典模拟之间的指数通信间隙

Exponential communication gap between weak and strong classical simulations of quantum communication

Alberto Montina

摘要:

经典地模拟量子态的通信的最普通的方法是传输量子态本身的经典描述。然而,如果模拟是准确的,这需要无限数量的经典通信。一个更有趣、要求可能更低的策略是将量子态的全部信息编码到通信变量的概率分布中,这样就不会在每次Single Shot中发送这些信息。这种模拟称为弱模拟,与强模拟相反,强模拟中的量子态在单个镜头中进行通信。在本文中,我们介绍了一个有界错误的弱协议,用于模拟任意数量的量子比特的通信和随后的两个结果的测量组成的任意纯态投影仪和它的补充。该协议需要与量子比特的数量无关并且与Delta^{-1}成比例的经典通信量,其中Delta是协议的误差和自由参数。相反,有界错误强协议需要大量的经典通信,随着固定错误的量子位数呈指数增长。我们的结果改进了以前的协议,基于Johnson-Lindenstrauss引理,通信成本缩放为Delta^{-2} log Delta^{-1}。

英文摘要:

The most trivial way to simulate classically the communication of a quantum state is to transmit the classical description of the quantum state itself. However, this requires an infinite amount of classical communication if the simulation is exact. A more intriguing and potentially less demanding strategy would encode the full information about the quantum state into the probability distribution of the communicated variables, so that this information is never sent in each single shot. This kind of simulation is called weak, as opposed to strong simulations, where the quantum state is communicated in individual shots. In this paper, we introduce a bounded-error weak protocol for simulating the communication of an arbitrary number of qubits and a subsequent two-outcome measurement consisting of an arbitrary pure state projector and its complement. This protocol requires an amount of classical communication independent of the number of qubits and proportional to Delta^{-1}, where Delta is the error and a free parameter of the protocol. Conversely, a bounded-error strong protocol requires an amount of classical communication growing exponentially with the number of qubits for a fixed error. Our result improves a previous protocol, based on the Johnson-Lindenstrauss lemma, with communication cost scaling as Delta^{-2} log Delta^{-1}.

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。

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