Studyof Ultrastrong Squeezing Based On Circuit QED

The squeezing of quantum states enables the reduction of quantum noise and the creation of quantum correlations,so it has great potential in a variety of fields,from high-precision quantum measurements to continuous variable quantum information process.However,implementing strong squeezing required for eminent applications is difficult,twenty years of intensive research after the first successful demonstration of squeezed state in 1985 could only realize a squeezing not more than 6 d B.Only in recent years a factor of 10(10d B)quantum-noise squeezing has been achieved with light and microwave circuits.So,how to produce strong squeezing and ultrastrong squeezing of quantum states have become interested subject to people.Here we propose a technique for producing ultrastrong squeezing of microwave photonic modes by means of superconducting electric LC resonator circuits.We show that ultrastrong single-mode squeezing and ultrastrong two-mode squeezing as well as the Einstein-Podolsky-Rosen type of entangling can be generated by tuning the driving frequency of the micromechanical resonator.After calculated,a factor of 100(20 d B)quantum-noise squeezing should be readily achievable in the weak coupling regime.In the strong and ultrastrong coupling regime even higher squeezing will be feasible in our setup.