We study ^（87）Rb Bose-Einstein condensation（BEC） loading into the pulse of the one-dimensional（1D） optical lattice experimentally.The lattice is turned on abruptly,held constant for a variable time,and then turned off abruptly.The measurement of the depth of the optical lattice is obtained by Kapitza-Dirac scattering.The temporal matter-wave-dispersion Talbot effect with ^（87）Rb BEC is observed by applying a pair of pulsed standing waves（as pulsed phase gratings） with the separation of a variable delay.
We report the experimental achievement of ^（87）Rb Bose-Einstein condensation in a magnetic trap with microwave and radio frequency（RF） induced evaporation.Evaporative cooling is realized by using 6.8 GHz microwave radiation driving the ^（87）Rb atoms to transit from the ground-state hyperfine state ｜F=2,m_F= 2〉to ｜F=l,m_F=1〉.Compared with RF-induced evaporation,^（87）Rb atoms are hardly to achieve pure condensate by microwave evaporation cooling due to the effect of atoms in the ｜F=1,m_F=1〉state being pumped back into the trapping ｜F=2,m_F=1〉state.
We report the experimental preparations of the absolute ground states of 87Rb and 40K atoms （｜F = 1, mF = 1 ） ＋ ｜F = 9/2, rnF ： -9/2）） by means of the radio-frequency and microwave adiabatic rapid passages, and the observation of magnetic Feshbach resonances in an ultracold mixture of bosonic STRb and fermionic 40K atoms between 0 T and 6.0 × 10^-2 T, including 7 homonuclear and 4 heteronuclear Feshbach resonances. The resonances are identified by the abrupt trap loss of atoms induced by the strong inelastic three-body collisions. These Feshbach resonances should enable the experimental control of interspecies interactions.
We report an experimental generation of polarization-entangled photon pairs in a cold atomic ensemble. A single Stokes photon and one spin-wave excitation are simultaneously created via spontaneous Raman scattering. The spin-wave excitation is then converted into an anti-Stokes photon via an electromagnetic-induced-transparency reading process. The measured cross-correlation functions between the Stokes and anti-Stokes photons for two orthogonal polarizations are -75 and 74, respectively, at a generation rate of the photon pair of -60/s. Based on such correlations, we obtain polarization-entangled photon pairs, whose Bell parameter is S = 2.77 4- 0.01, violating Bell-CHSH inequality by -77 standard deviations. The presented polarization-entangled photon source has high entanglement degree and fast generation rate, which will promise us to apply it in future quantum repeater.
Yuelong WuShujing LiWei GeZhongxiao XuLong TianHai Wang
