Dynamics Of Quantum Entanglement And Non-locality In Cavity QED System

Entanglement and non-locality, two of the most striking features of quantummechanics, not only useful for testing the foundations of quantum mechanics itself,but also play a key role in quantum information processing (QIP) such as quantumcomputation, quantum communication, and quantum cryptography. It has been morethan one hundred years since quantum hypothesis was proposed by Planck in the year1900. In these years, quantum mechanics have got great advance. However, peoplestill know little about the essence of quantum entanglement and non-locality. On theone hand, how to realize quantum entanglement simply with existing technology isone of the key points. On the other hand, the fragility of nonlocal quantum coherenceis recognized as a main obstacle to realizing QIP. What’s worse, Yu and Eberlyrecently show that even under the influence of pure vacuum noise two entangledqubits may become completely disentangled in a finite time, an interestingphenomenon termed entanglement sudden death (ESD). It’s difficult to prove thisphenomenon in multi-qubits system. However, we can easily discuss its non-localityby using Bell inequality. The expectation of bell operator may also reduce to zerocompletely in a finite time which is similar to that occur in quantum entanglement.Jaeger and Ann first studied this phenomenon and termed it bell non-locality suddendeath (BNSD). Therefore, special investigations are needed to study the dynamicsproperties of quantum entanglement and non-locality systematically and find out thesolution to see “anti-ESD” or “anti-BNSD”.The thesis investigates how quantum entanglement and non-locality evolve incavity QED systems, which includes the following four sections.(1)We investigate quantum non-locality dynamics of a three-level atom and aclass of two-mode non-classical states (including the entangled coherent state, thepair coherent state and the two-mode squeezed state) interacting in the non-degeneratetwo-photon Jaynes-Cummings (J-C)model.(2) The entanglement characteristics including the so-called sudden death effect between two identical two-level atoms trapped in two separate cavities connected byan optical fiber are studied.(3) We discuss the one-excitation dynamics of a quantum system consisting oftwo fiber-coupled cavities, each containing a two-level atom. Our investigation focuson the influences of atom-cavity detuningδ on the dynamics under the certaincoupling limits.(4) We consider the one-excitation dynamics of two atomic qubits, trapped inseparate cavities coupled through a short optical fiber. The studies emphasize thepositive effect of cavity-fiber detuning δ on the dynamics under the certain couplinglimits.