Research Of Generation Of Spin Squeezed States In Optical Cavity

Recently,non-classical effects produced by interaction between quantum light field and atomic enesmbles are a focus of research in quantum optics.Studing these non-classical effects not only help us better understand what is the nature of light,but also has some great research value in practical applications.Quantum entanglement and spin squeezing are ywo typical non-classical effects,and they have very important application in quantum computing,quantum information processing,and precision measurement.This paper mainly studies how to generate spin squeezing and quantum entanglement in the optical cavity,it mainly includes the following two parts:1.Research on the generation of spin-squeezed states in optical cavities.We have found through research that if a three-level atomic system is placed in an optical cavity and then a strong laser is injected into the interior,the atomic ensemble will produce spin characteristics under the action of the strong light field and the cavity mode.By analyzing these spin characteristics,we find that it is a one-axis twisting Hamiltonian.If a suitable magnetic field is added,the one-axis twisting Hamiltonian can be transformed into a two-axis twisting Hamiltonian,which can improve the squeezing degreec of the system.We also studied the effect of noise on the spin process and found that even in the presence of noise,the system can produce very high squeezing degree.2.The study of the generation of entangled states in the atomic system in an optical cavity.Two atomic ensembles are placed in the same optical cavity.Studies have shown that the two ensembles are entangled with each other under the action of a strong driving field,which is rooted in nondemolition interactions between atoms.Using Simon's Peres-Horodecki criterion,it is proved that there is a non-classical relationship between the two atomic ensembles under this Hamiltonian.Nondemolition interaction is a very important quantum gate in the quantum calculation of continuous variables,so we believe that this scheme also plays a certain role in the development of quantum computing.