Creation of the quantum cat state by using the collisional interaction of Bose-Einstein condensate and estimation of the quantum state

本研究的目的是利用中性原子气体的玻色-爱因斯坦凝聚体创造量子猫态。我们构建了超高真空系统来运行双磁光阱，并制作了三叶草型磁阱。虽然成功地创造了^<87 b> Rb原子的玻色-爱因斯坦凝聚体，但由于磁阱引起的屏蔽盒磁化，很难抑制小于10μG的残余磁场。因此，我们开始构建一个新的装置，该装置仅使用光捕获技术来产生玻色-爱因斯坦凝聚。我们成功地构建了波长为1.06μm、功率为10W的YVO_4激光器。将YVO_4激光器的输出功率引入到包含真空玻璃电池的Bow-tie腔中，我们成功地制造出了势深足以捕获激光冷却Rb原子的光阱。注意到系统已经被磁屏蔽所包围，在双磁光阱的作用下可以保持超低的剩余磁场。残余磁场小于10μG，磁梯度被抑制到2uG/cm。我们计划很快通过使用这些实验装置来实现我们最初的目的

The purpose of the research is to create the quantum cat state with Bose-Einstein condensate of neutral atomic gas. We constructed the ultra high vacuum system to operate the double magneto-optical trapping and also made the clover-leaf type of the magnetic trap. While the Bose-Einstein condensate of ^<87>Rb atoms was successfully created, it was hard to suppress the residual magnetic field less than 10μG because of the magnetization of the shield box caused by the magnetic trap. We thus started constructing a new setup which creates Bose-Einstein condensate by using only optical trapping technique. We succeeded in constructing a YVO_4 laser with its wavelength of 1.06μm and its power of 10W. Introducing the output power of the YVO_4 laser into the Bow-tie cavity which includes the vacuum glass cell, we succeeded in creating the optical trap whose potential depth is enough deep to catch the laser cooled Rb atoms. It is noted that the system is already surrounded by the magnetic shield and we can keep ultra low residual magnetic field under the operation of the double magneto-optical trapping. The residual magnetic field is less than 10μG and the magnetic gradient is suppressed to 2uG/cm. We are planning to implement our initial purpose by using these experimental setups soon