报告时间：12月25日下午3点
报告地点：近代物理系210会议室
报告人：李朝红教授 中山大学报告题目：Quantum metrology via many-body quantum interferometry across quantum phase transitions、
报告摘要：Many-body quantum effects such as entanglement and spin squeezing have been widely used to improve measurement precisions in quantum metrology. On ther other hand, most quantum phase transitions relate to the change of entanglement entropy. In this talk, I will discuss how quantum phase transitions can be used in quantum metrology. The beam splitting, in which an initial nondegenerate ground state evolves into a highly entangled state, is achieved by adiabatically driving the system from a nondegenerate regime to a degenerate one. Inversely, the beam recombination, in which the output state after interrogation becomes gradually disentangled, is accomplished by adiabatically driving the system from the degenerate regime to the nondegenerate one. The phase shift, which is accumulated in the interrogation process, can then be easily inferred via population measurement. We apply our scheme to Bose condensed atoms and trapped ions and find that Heisenberg-limited precision scalings can be approached. Our proposed scheme does not require single-particle resolved detection and is within the reach of current experiment techniques.
