Information Security and National Computing Grid Laboratory, School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China.
Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA.
Sci Rep. 2016 Jul 18;6:29939. doi: 10.1038/srep29939.
Most of previous quantum computations only take use of one degree of freedom (DoF) of photons. An experimental system may possess various DoFs simultaneously. In this paper, with the weak cross-Kerr nonlinearity, we investigate the parallel quantum computation dependent on photonic systems with two DoFs. We construct nearly deterministic controlled-not (CNOT) gates operating on the polarization spatial DoFs of the two-photon or one-photon system. These CNOT gates show that two photonic DoFs can be encoded as independent qubits without auxiliary DoF in theory. Only the coherent states are required. Thus one half of quantum simulation resources may be saved in quantum applications if more complicated circuits are involved. Hence, one may trade off the implementation complexity and simulation resources by using different photonic systems. These CNOT gates are also used to complete various applications including the quantum teleportation and quantum superdense coding.
大多数先前的量子计算仅利用了光子的一个自由度（DoF）。一个实验系统可能同时具有多种自由度。在本文中，我们利用弱交叉克尔非线性，研究了依赖于具有两个自由度的光子系统的并行量子计算。我们构造了近确定性受控非门（CNOT）门，这些门作用于两光子或单光子系统的偏振空间自由度上。这些 CNOT 门表明，两个光子自由度可以在理论上被编码为独立的量子比特，而无需辅助自由度。只需要相干态。因此，如果涉及更复杂的电路，在量子应用中可能会节省一半的量子模拟资源。因此，可以通过使用不同的光子系统来权衡实现复杂性和模拟资源。这些 CNOT 门还用于完成各种应用，包括量子隐形传态和量子超密集编码。
