Fast Preparation Of Multi-atom Entangled States In Coupled Cavity Array System

Quantum information is one of the hot topics of current international frontier,and entanglement is a precious resource in quantum information processing.Thus,the manipulation of the entangled states is the basic task for quantum information.Compared to other physical systems,the cavity QED system is considered as a natural platform for manipulating kinds of entanglement,since the photons are well suited to distribute information throughout the system while the atoms are suitable for storing information.Coupled cavity QED system has the advantage of scalability,which can provide technical support for quantum information.Moreover,the shortcuts to adiabatic passage,owing to it both has the advantages of adiabatic process and can quickly achieve target quantum state,has attracted much attention in recent years.This thesiss mainly focus on how to rapidly prepare and manipulate entangled states in coupled cavity array system.The main contents are as follows:In Chapter 1,we introduce the quantum entangled states,cavity QED system and coupled cavity QED system,quantum Zeno dynamics and quantum Zeno effect,and shortcut to adiabaticity.The major research content and structure are given at the end of this chapter.In Chapter 2,we study the one-excitation dynamics of a two-dimensional coupled cavity array system composed of four cavities,which each contains a two-level atom.By adjusting cavity-cavity hopping rate u,the atom-cavity detuning ? and the initial excitation belongs to the atom,a wide variety of time-evolution behaviors can be realized.Under a certain condition,the four-atom entangled states can be obtained.In Chapter 3,we construct shortcuts to adiabatic passage to fast preparation of multi-atom entangled states in coupled cavities system by combining transitionless quantum driving and quantum Zeno subspaces.Numerical simulation demonstrates that the interaction time required for the creation of the entangled states is much shorter than the adiabatic passage.Moreover,the scheme is robust against the decoherence and parameter variation.In Chapter 4,according to the quantum Zeno dynamics,shortcuts to adiabatic passage are constructed to fast preparation of W state among atomic ensembles based on the invariant-based inverse engineering in coupled cavities system.Numerical simulation demonstrates that the shortcut scheme is not only fast,but robust against decoherence and the defects of operating.In Chapter 5,we construct shortcuts to adiabatic passage to fast preparation of three-qubit GHZ state based on the invariant-based inverse engineering in coupled cavities system.Similarly,numerical simulation demonstrates that the shortcut scheme is fast,and robust against decoherence and parameter variation.Finally,the results are summarized at the end of the paper.