The Potential Application Of The Product Of Coherent State And Schrodinger's Cat State In Quantum Phase Estimation

In this graduate thesis,we focus on the product of coherent state and Schrodinger's cat state.With the purpose of quantum phase estimation to find appropriate quantum states,to optimize mechanical parameters and to perform data processing,which make the fluctuation of the estimator can be lower than the standard quantum limit.We systematically study the basic steps of the quantum phase measurement,the basic method of the binary outcomes measurement,the quantum Fisher information and the classical Fisher information.First,we consider the product states of coherent light and Schrodinger cat states as the input state of MZI.We study the quantum Fisher information(QFI)under the ideal condition without any noise:1.We give the phase sensitivity and the optimal quantum Fisher information under the phase matching condition cos[2(?a-?b)]= +1,here,?a/b is the phase of coherent/cat state;2.In the experiment n?1,we find the optimal relationship between nb and na;3.We also show that the even cat state has better quantum information Fisher than the odd cat state.4.We also prove that quantum state is the main factor for transformation.In addition,we take the coherent light as an example.We study the phase estimation and its fluctuation in binary-outcome measurement[1],and compare with the recently experimental results:1.Homodyne detection can obtain super resolution signal,and the phase sensitivity in the experiment is close to the shot noise limit by coherent state and a simply efficient homodyne detector;2.Parity detection and zero-nonzero photon counting measurement can also reach super resolution,the phase sensitivity is also close to the shot noise limit.Next,we consider the loss in the experiment,and make the numerical simulation of the output signal and the sensitivity in parity measurement and Z detection.By comparing the inversion estimation and maximum likelihood estimation,we find that the inversion estimation and maximum likelihood estimation should be the same for enough times of experiments and detections,in contrast,inversion estimation is more simple.In the fourth chapter,we study coherent state(?)Schrodinger cat state,we prove that the classical Fisher information under the phase matching condition can stature the quantum Fisher information.This result is in qualitative agreement with recent results[2].Finally,the author gives the conclusion and prospection of the whole paper.Some results of this paper have been published.