Several Application Studies In The Field Of Quantum Information Based On A Rydberg Atomic System

In recent years,Rydberg atom has been widely used in the quantum information and quantum computing due to its unique properties,which provides a variety of possibilities for its research.Due to the highly controllable long range interaction between Rydberg atoms,many interesting physical phenomena are generated by this interaction,including Rydberg blockade and antiblockade.Blockade means that only one atom is allowed to excite into Rydberg state within the blockade radius so as to suppress the excitations of other atoms.This effect has been widely used in quantum simulation,the construction of quantum logic gates and the preparation of quantum entanglement.The antiblockade refers to that atoms can be simultaneously excited to Rydberg states by adjusting the relationship between the laser detuning and the interaction intensity.Also,the preparation of entanglement or the operation of quantum logic gates can be realized based on the antiblockade mechanism,which greatly promotes the development of quantum science.Using these two effects peculiar to Rydberg atom,people have realized the preparation of entanglement and the operation of quantum logic gate in Rydberg atomic system based on different methods.Firstly,we proposed a scheme to accelerate the preparation of dissipative entanglement by using a periodic modulated pulse.Different from traditional schemes based on Rydberg blockade,we counterintuitively regard dissipation as a resource.The system characteristic frequency is consistent with the external driving frequency,producing obvious modulation in the unitary evolution behavior of optical pumping dynamics,the population on the excited state can decay to the target state rapidly.Our scheme is robust to the requirement of initial states and the imperfect satisfaction of antiblockade,overcomes the complex level structure and the long convergence time under the traditional antiblockade mechanism.It provides another new idea for the preparation of the two atom maximum entanglement in the experiment.Secondly,quantum logic gates can also be used for the preparation of quantum entanglement states.Based on the optimization algorithm,we minimized the Rydberg C-NOT gate model.By using genetic algorithm to optimize the optical pulse parameters,the number of pulses required by the scheme is simplified to a single pulse,which avoids switching laser between different spatial positions quickly,shortens the gate operation time and greatly re-duces decay error.Depending on the adaptive ability of genetic algorithm,the scheme is not limited to the Rydberg strong blockade,and can match a set of feasible parameters in the case of weak interaction,which is beneficial to realize the gate operation in the multi-qubit array.In the preparation of dissipative entanglement,the antiblockade condition caused by atomic motion cannot be satisfied in real time,and the adaptive ability of genetic algorithm can also be used to compensate the defects.