This Letter reports the first experimental demonstration of Greenberger-Horne-Zeilinger (GHZ) entanglement swapping. We start with three pairs of entangled photons. Upon projection of three single photons, each from an entangled pair, into a GHZ state, the other three originally independent photons are entangled in a GHZ state-creation of multiparticle entanglement without any direct interaction. This scheme may facilitate networks for quantum telephone exchange, multiparty quantum communication and distributed quantum computation.

Chao Yang Lu;Tao Yang;建伟 潘

Physical Review Letters

2009-8-6

We present a surface textured Si SPAD with improved detection efficiency and without sacrificing dark count rate or jitter distribution. Texturing reduces reflection, allows weak light trapping and is CMOS and lithography compatible.

Kai Zang;Xun Ding;Xiao Jiang;Yijie Huo;Matthew Morea;Xiaochi Chen;Ching Ying Lu;Muyu Xue;Yusi Chen;Colleen Shang;Theodore I. Kamins;Qiang Zhang;建伟 潘;James S. Harris

2017

Cold atoms with laser-induced spin-orbit (SO) interactions provide a platform to explore quantum physics beyond natural conditions of solids. Here we propose and experimentally realize two-dimensional (2D) SO coupling and topological bands for a rubidium-87 degenerate gas through an optical Raman lattice, without phase-locking or fine-tuning of optical potentials. A controllable crossover between 2D and 1D SO couplings is studied, and the SO effects and nontrivial band topology are observed by measuring the atomic cloud distribution and spin texture in momentum space. Our realization of 2D SO coupling with advantages of small heating and topological stability opens a broad avenue in cold atoms to study exotic quantum phases, including topological superfluids.

Zhan Wu;Long Zhang;Wei Sun;Xiao Tian Xu;Bao Zong Wang;Si Cong Ji;友金 邓;Shuai Chen;Xiong Jun Liu;建伟 潘

Science

2016-10-7

The distribution of entangled states between distant locations will be essential for the future large-scale realization of quantum communication schemes such as quantum cryptography and quantum teleportation. Because of unavoidable noise in the quantum communication channel, the entanglement between two particles is more and more degraded the further they propagate. Entanglement purification is thus essential to distil highly entangled states from less entangled ones. Existing general purification protocols are based on the quantum controlled-NOT (CNOT) or similar quantum logic operations, which are very difficult to implement experimentally. Present realizations of CNOT gates are much too imperfect to be useful for long-distance quantum communication. Here we present a scheme for the entanglement purification of general mixed entangled states, which achieves 50 per cent of the success probability of schemes based on the CNOT operation, but requires only simple linear optical elements. Because the perfection of such elements is very high, the local operations necessary for purification can be performed with the required precision. Our procedure is within the reach of current technology, and should significantly simplify the implementation of long-distance quantum communication.

建伟 潘;C. Simon;Č Brukner;A. Zeilinger

Nature

2001-4-26

We experimentally investigate the quantum criticality and Tomonaga-Luttinger liquid (TLL) behavior within one-dimensional (1D) ultracold atomic gases. Based on the measured density profiles at different temperatures, the universal scaling laws of thermodynamic quantities are observed. The quantum critical regime and the relevant crossover temperatures are determined through the double-peak structure of the specific heat. In the TLL regime, we obtain the Luttinger parameter by probing sound propagation. Furthermore, a characteristic power-law behavior emerges in the measured momentum distributions of the 1D ultracold gas, confirming the existence of the TLL.

Bing Yang;Yang Yang Chen;Yong Guang Zheng;Hui Sun;Han Ning Dai;Xi Wen Guan;Zhen Sheng Yuan;建伟 潘

Physical Review Letters

2017-10-18

Bell's theorem states that certain statistical correlations predicted by quantum physics for measurements on two-particle systems cannot be understood within a realistic picture based on local properties of each individual particle - even if the two particles are separated by large distances, Einstein, Podolsky and Rosen first recognized the fundamental significance of these quantum correlations (termed 'entanglement' by Schrodinger) and the two-particle quantum predictions have found ever-increasing experimental support. A more striking conflict between quantum mechanical and local realistic predictions (for perfect correlations) has been discovered; but experimental verification has been difficult, as it requires entanglement between at least three particles. Here we report experimental confirmation of this conflict, using our recently developed method to observe three-photon entanglement, or 'Greenberger-Horne-Zeilinger' (GHZ) states. The results of three specific experiments, involving measurements of polarization correlations between three photons, lead to predictions for a fourth experiment; quantum physical predictions are mutually contradictory with expectations based on local realism. We find the results of the fourth experiment to be in agreement with the quantum prediction and in striking conflict with local realism.

建伟 潘;Dik Bouwmeester;Matthew Daniell;Harald Weinfurter;Anton Zellinger

Nature

2000-2-3

Bcl-2 is one of the most important antiapoptotic members in mammals and prevents many forms of apoptosis in a variety of cell types. Our previous study revealed that overexpression of Bcl-2 significantly suppressed H₂O₂/NaCl-induced programmed cell death via inhibiting the transcriptional activation of OsVPE2 and OsVPE3 in transgenic rice. However, Ca²⁺ and K⁺ homeostasis of this process remains largely unknown. In the present study, we investigate whether nonselective cation channels (NSCC) blockers affect Bcl-2 function in rice under salt stress and how Bcl-2 affects ion homeostasis in salt stress-induced PCD. The results showed that overexpression of Bcl-2 significantly decreased transient elevations in the cytosolic Ca²⁺ levels, inhibited NaCl-induced K⁺ efflux but not H⁺ efflux across the plasma membrane, and further suppressed the expression levels of OsVPE2 and OsVPE3, leading to the inhibition of salt-induced PCD and increase of tolerance to salt stress in transgenic rice. During the NaCl-induced PCD, the effects of a NSCC blocker La³⁺ on ion homeostasis and VPEs expression in wild-type were similar to the effects of Bcl-2 overexpression in transgenic line. However, a synergistic effect of Bcl-2 and La³⁺ was not obviously detectable. Our results suggested that Bcl-2 played an important role in suppression of NaCl-induced PCD by disruption of ion homeostasis, providing an insight into the mechanistic study of plant VPEs, cytosolic Ca²⁺ level and K⁺ efflux.

Yongho Kim;Mingqiang Wang;Yu Bai;Zhanghui Zeng;Fu Guo;Ning Han;Hongwu Bian;Junhui Wang;建伟 潘;睦元 朱

Plant Physiology and Biochemistry

2014

The decoy-state method has been developed rapidly in quantum key distribution (QKD) since it is immune to photon-number splitting attacks. We examine two-basis-detector-efficiency asymmetry, which exists in realistic scenarios. By using the recent 4-intensity decoy-state optimization protocol, we report an implementation of high-rate QKD with asymmetric basis-detector efficiency, demonstrating a 1.9 to 33.2 times higher key rate than previous protocols in the situation of large basis-detector-efficiency asymmetry. The results ruled out an implicit assumption in QKD that the efficiency of Z basis and X basis are restricted to be the same. This work paves the way towards a morepractical QKD setting.

Hui Liu;Zong Wen Yu;Mi Zou;Yan Lin Tang;Yong Zhao;Jun Zhang;Xiang Bin Wang;Teng Yun Chen;建伟 潘

Physical Review A

2019-10-14

We have demonstrated upconversion detection at the single photon level in the 2 μm spectral window using a pump wavelength near 1550 nm, a periodically poled lithium niobate (PPLN) waveguide, and a volume Bragg grating (VBG) to reduce noise. We achieve a system photon detection efficiency of 10%, with a noise count rate of 24,500 counts per second, competitive with other 2 μm single photon detection technologies. This detector has potential applications in environmental gas monitoring, life science, and classical and quantum communication.

Guo Liang Shentu;Xiu Xiu Xia;Qi Chao Sun;Jason S. Pelc;M. M. Fejer;Qiang Zhang;建伟 潘

Optics Letters

2013-12-1

Based on the linear quantum transformation theory, we present a new approach to obtain the explicit expressions of energy spectrum and simplify the derivations of partition functions for general multi-mode boson and fermion quadratic systems.

建伟 潘;Yong De Zhang;G. G. Siu

Chinese Physics Letters

1997