Study On Quantum Properties Of Biatomic Bit System In Vacuum Cavity Environment

A two-level atom as a two-state quantum system is an important candidate for quantum bits,called atomic bits.In the case of not destroying its coherence,it is the information storage unit of quantum computing.The diatomic bit system is a quantum information system with typical meaning under the vacuum cavity field environment.The system has important quantum properties such as quantum coherence,quantum entanglement and information entropy compression,and has important applications in low noise quantum information processing.In this paper,we use the whole quantum theory to focus on two kinds of research:one is to consider the two atomic bits that are initially in the entangled state,and one of them is injected into the vacuum state cavity to generate multiphoton resonance interaction,and the atomic bit outside the operating cavity controls the atomic bit in the cavity.The theoretical study on the entropy squeezing property and the maximum coherence recovery of the atom in the photon process;the second kind is to study the dual-atom bit quantum echo control and entanglement information exchange in the dual-mode vacuum field environment;many meaningful results are obtained:1.Using the theory of quantum information entropy,the information entropy compression properties of the atomic bits in the cavity before and after the logic gate operation and the ground state measurement are performed in the above model.The results show that the atomic bits in the cavity do not produce entropy compression before the atomic bits outside the cavity;after the Hadamard?H?and H-gate operations are applied to the extra-atomic atomic bits,the intracavity atomic bit generation period in the k=3 photon process For the?/?3!?^1/2 entropy compression phenomenon,the optimal entropy squeezed state can be prepared.In the multi-photon process of k>3,as the number of photons increases,the entropy compression factor E?S_x?produces high-frequency oscillations.Generally,entropy compression occurs frequently,and the optimal entropy compression is generated frequently.The increase is beneficial to the experimental implementation of quantum communication and quantum computing in a noisy environment.2.The two-two-level atoms that are initially in the maximum entangled state are studied.The maximum coherence recovery in the atomic multiphoton process in the atomic control cavity outside the logic gate is controlled.Studies have shown that before the operation of the extra-atomic atoms,the atoms in the cavity are always in the dephasing state,which is not conducive to the realization of quantum calculation;after the operation of the extra-atomic atoms,for the multi-photon process of 2?k?10,the intra-atomic atomic reduction density matrix is not diagonal,It exhibits periodic evolution;at n?/2?k!?^1/2,its maximum coherence is restored,and the largest coherent superposition state is prepared.For the multiphoton process of 10?k?20,the non-diagonal elements of the atomic density matrix in the cavity exhibit high-frequency oscillation,and the amplitude changes nonlinearly;the maximum coherence recovery period becomes smaller,and the number of recovery times increases in one cycle.An experimental circuit diagram is given.3.The quantum state fidelity,quantum echo theory and the two-element quantum bit quantum echo control and the Bell state exchange under the action of the dual-mode vacuum cavity field are studied.Discuss the effect of initial entanglement factor and relative coupling strength R=g₁/g₂ on quantum fidelity.The results show that in the same coupling case R=1,a quantum echo with a period of?is always generated,and the value of fidelity can be controlled by selecting the appropriate?and controlling the interaction time.In different coupling cases,the quantum echoes with periods of?,2?and 4?are formed by adjusting R,which results from the non-Markov properties of the dual-mode vacuum cavity field.Based on this property,a cyclic exchange scheme from the two-atom bit to the two-mode cavity field is proposed.