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arXiv quant-ph/0108001quant-ph
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Franson型实验实现两量子比特量子逻辑门

Franson-type experiment realizes two-qubit quantum logic gate

Kaoru Sanaka, Karin Kawahara, Takahiro Kuga

摘要:

量子计算机在解决大整数分解、模拟量子系统和数据库搜索等问题方面有很大的改进。使用光子作为量子比特(qubit)是实现通用量子计算机的最有前途的方法之一,因为光子的相干叠加态对各种退相干源非常鲁棒。然而,实现双量子比特(光子)门太困难了,因为它需要光子之间的巨大非线性。在这里,我们展示了一个受控非(CNOT)门的实现,量子计算中最重要和最基本的两量子比特门,通过扩展我们以前的研究。我们实验的核心是在弗兰森型实验中对双光子符合的条件测量[7]。光子计数测量与双量子比特门所需的非线性起着相同的作用,我们的系统再现了CNOT门的真值表。此外,我们还通过我们的门从叠加态中产生了纠缠态,这清楚地证明了我们的门是一个量子逻辑门。我们的研究结果使得操纵包括纠缠在内的光子量子态成为可能,并代表了量子计算中各种算法操作的重大进展。

英文摘要:

Quantum computers promise great improvements in solving problems such as factoring large integers, simulating quantum systems, and database searching. Using a photon as a quantum bit (qubit) is one of the most promising ways to realize a universal quantum computer because the coherent superposition state of a photon is very robust against various sources of decoherence. However, it is too difficult to realize two-qubit (photon) gates because it requires huge nonlinearity between photons. Here we show the realization of a controlled-NOT (CNOT) gate, the most important and elemental two-qubit gate for quantum computation, by extending our previous research. The heart of our experiment is the conditional measurement of two-photon coincidences in the Franson-type experiment[7]. The photon counting measurement plays the same role as the nonlinearity required for the two-qubit gate, and our system reproduces the truth table of the CNOT gate. Furthermore, we create an entangled state from the superposition state by our gate, which is clear evidence that our gate works as a quantum logic gate. Our results make it possible to manipulate the quantum state of photons including entanglement and represent significant progress in the operation of various algorithms in quantum computation.

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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