Author Affiliations
Abstract
Department of Physics, Mathematics and Science College of Shanghai Normal University, Shanghai 200234, China
Recently, the nested Mach–Zehnder interferometer [Phys. Rev. Lett. 111, 240402 (2013)] was modified by adding Dove prisms in a paper [Quantum Stud.: Math. Found. 2, 255 (2015)], and an interesting result is that, after the Dove prisms were inserted, a signal at the first mirror of the nested interferometer was obtained. But, according to the former original paper, the photons have never been present near that mirror. In this work, we interpret this result naturally by resorting to the three-path interference method. Moreover, we find that even though the photons have been somewhere, they can hide the trace of being there.
multi-path interference quantum foundations Chinese Optics Letters
2021, 19(1): 012701
1 中国科学院上海光学精密机械研究所强场激光物理国家重点实验室, 上海 201800
2 中国科学院大学, 北京 100039
3 上海师范大学数理学院, 上海 200234
用无退相干子空间的方法抑制集体退相干,实现不受比特反转错 误影响的通用量子计算。 该方案基于腔电动力学系统,用囚禁于腔中的2个相邻原子编码1个逻辑比特,构造出抑制集体比特 反转错误的4维无退相干子空间。通过调节外加光场与腔的耦合,在无退相干子空间中完成了2个非 对易的单比特操作和控制相位门,实现了克服集体比特反转错误的通用量子计算。
量子光学 通用量子计算 无退相干子空间 比特反转错误 quantum optics universal quantum computation decoherence-free subspace bit-flip error
Author Affiliations
Abstract
1 State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 University of Chinese Academy of Sciences, Beijing 100039, China
3 Department of Physics, Shanghai Normal University, Shanghai 200234, China
We investigate the reflected field for few-cycle ultra-short laser pulses propagating through resonant media embedded within wavelength-scale structures. Full-wave Maxwell–Bloch equations are solved numerically by using the finite-difference time-domain method. The results show that the spectral feature of the reflected spectrum is determined by the Bragg reflection condition, and that the periodic structure of a dense atomic system can be regarded as a one-dimensional photonic crystal and even as a highly reflective multilayer film. Our study explains the suppression of the frequency shifts in the reflected spectrum based on the Bragg reflection theory and provides a method to control the frequency and frequency intervals of the spectral spikes in the reflected spectrum.
320.2250 Femtosecond phenomena 320.7150 Ultrafast spectroscopy 020.1335 Atom optics Chinese Optics Letters
2015, 13(12): 123201
Author Affiliations
Abstract
We show that controlled-controlled-NOT (CCN) operation-based entanglement purification protocol can be further improved. CCN protocol requires Bell state measurements after performing the CCN operations. In the original CCN protocol, the measured states are assumed to be destroyed. However, if controlled-NOT gates are used to perform such Bell state measurements, in some unsuccessful situations of the CCN protocol, one can further purify the two mixed entangled states which are to be measured. In this way, the total efficiency of the CCN protocol is further increased.
270.0270 Quantum optics 270.5565 Quantum communications 270.5585 Quantum information and processing Chinese Optics Letters
2012, 10(4): 042701
Author Affiliations
Abstract
Shandong Vocational and Trade College, Jining 2720172 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800
We propose a new repeat-until-success (RUS) measurement-based scheme to implement quantum controlled phase gates according to the effect of dipole-induced-transparency (DIT) in a cavity and single-photon interference at a 50:50 beam-splitter. In our scheme, the DIT effect can appropriately attach a photon to the state of the dipoles according to their initial state, and in this way, a suitably encoded dipole-photon state is thus prepared. The measurement of the photon after it passing through a 50:50 beam-splitter can project the encoded matter-photon state to either a desired phase gate operation for the matter qubits or to their initial states. The recurrence of the initial state permits us to implement the desired entangling gate in a RUS way.
偶极子诱导透明现象 光子分束器单光子干涉 受控相位门 270.5585 Quantum information and processing 230.1360 Beam splitters 040.5160 Photodetectors Chinese Optics Letters
2009, 7(1): 0182
Author Affiliations
Abstract
1 State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800
2 Graduate School of the Chinese Academy of Sciences, Beijing 100039
3 Department of Physics, Blk S12, National University of Singapore, 2 Science Drive 3, Singapore 117542
Entanglement dynamics of two non-interacting atoms in a squeezed vacuum reservoir is studied. Several examples with different initial entangled states are investigated, and it is found that entangled atoms become disentangled faster in squeezed vacuum than in ordinary vacuum, and larger squeezing results in faster entanglement decay. The time evolution of the concurrence and the separability "distance" 'Lambda' can be used to explain this novel entanglement sudden death phenomenon.
纠缠 量子比特 共存(concurrence) 压缩真空 270.0270 Quantum optics 270.6570 Squeezed states Chinese Optics Letters
2007, 5(8): 484
