Generation Of Tree-Type Three-Dimensinal Entangled State And NOON State Via Adiabatic Techniques

With the development of quantum information science,quantum entanglement has been gradually recognized,and a large number of investigation has been made.Due to the non-local property,quantum entanglement was widely developed and used in quantum information.At the same time,the preparation of quantum entan-gled states have got a lot of attention,and this not only have promoted the devel-opment of relevant theoretical and experimental technology,but also have achieved the preparation of entangled state in a variety of physical systems.In this disser-tation,we introduce how to prepare a novel tree-type three-dimensional entangled states and NOON states using adiabatic technique based on cavity QED system.The main research contents are as follows:Based on adiabatic passage,we propose a scheme for generating a type of novel tree-type three-dimensional entangled state.In the scheme,an atom and two Bose-Einstein condensates are individually trapped in three spatially separated optical cavities which are connected by two optical fibers.We investigate the influence of various decoherence processes such as the spontaneous emission of atoms and the leakage of photons in the cavities and fibers on the fidelity of the entangled states.The numerical simulation results show that our scheme is robust to decoherence induced by the spontaneous emission of atoms and the leakage of photons in the cavities and fibers.The novel tree-type three-dimensional entangled states can be generated with high fidelity.Based on Lewis-Riesenfeld invariants and quantum Zeno dynamics,we propose an effective scheme for generating atomic NOON states via shortcuts to adiabatic passage.In the scheme,we used two fibers to connect three distant optical cavities.The two sets of A-type three-level atoms are stored in two transverse optical lattices,respectively,and translated inside and outside of the cavities A and C simultaneously and,respectively,while a double A-type atom is trapped in cavity B.The effects of photon leakage on fidelity are studied through the strict numerical simulation.The numerical simulation shows that our scheme is not only fast,but also robust against coherent.All of these schemes are feasible with present experimental techniques.They will provide reliable theory foundation for the experiment implementation of optical quantum information and quantum computation.