High entanglement generation and high fidelity quantum state transfer in a non-Markovian environment

This paper analyses a system of two independent qubits off-resonantly coupled to a common non-Maxkovian reservoir at zero temperature. Compared with the results in Markovian reservoirs, we find that much higher values of entanglement can be obtained for an initially factorized state of the two-qubit system. The maximal value of the entanglement increases as the detuning grows. Moreover, the entanglement induced by non-Maxkovian environments is more robust against the asymmetrical couplings between the two qubits and the reservoir. Based on this system, we also show that quantum state transfer can be implemented for arbitrary input states with high fidelity in the non-Markovian regime rather than the Markovian case in which only some particular input states can be successfully transferred.

Generation of entanglement in the atom-cavity-fibre system via adiabatic passage

A scheme, based on the system composed of three atoms separately trapped in three cavities coupled by optical fibres, for entangling two distant atoms via the adiabatic passage is proposed. It is found that the multi-particle W entangled state can also be generated. Moreover, the quantum information sharing can be implemented using this system. These results may be helpful for the implementation of quantum network and useful in quantum cryptography. This scheme is also convenient for operating since only the laser fields applied to the atoms need to be adjusted to accomplish the processes.

Multipartite entanglement generation with dipole induced transparency effect in indirectly coupled dipole-microcavity systems

We propose a feasible scheme of generating multipartite entanglement with the dipole induced transparency （D/T） effect in indirectly coupled dipole-microcavity systems. It is shown that the transmission spectrum is closely related with the interference of dipole-microcavity systems, and we can generate different classes of multi- partite entanglement, e.g., the Greenberger-Horne-Zeilinger state, the W state, and the Dicke state, of the di- pole emitters just by choosing an appropriate frequency of the incident photon. Benefiting from the DIT effect, the schemes may work in the bad or low-Q cavity regime only if the large Purcell factor of the dipole-microcavity system is fulfilled, and they are also insensitive to experimental noise, which may be feasible with present acces- sible technology.

Enhancing entanglement generation of two atoms in a cavity with white noise using classical driving fields

We investigate the entanglement dynamics of a quantum system consisting of two two-level atoms in a cavity with classical driving fields in the presence of white noise. The cavity is initially prepared in the vacuum state. Generally, the entanglement of two atoms decreases with the intensity of the thermal fields and the coupling strength of the two-level atoms to the thermal fields. However, we find that the entanglement of the quantum system can be enhanced by adjusting the frequency and the strength of the classical driving fields in the presence of white noise.

Fast quantum state transfer and entanglement for cavity-coupled many qubits via dark pathways

Quantum state transfer(QST)and entangled state generation(ESG)are important building blocks for modern quantum information processing.To achieve these tasks,convention wisdom is to consult the quantum adiabatic evolution,which is time-consuming,and thus is of low fidelity.Here,using the shortcut to adiabaticity technique,we propose a general method to realize high-fidelity fast QST and ESG in a cavity-coupled many qubits system via its dark pathways,which can be further designed for high-fidelity quantum tasks with different optimization purpose.Specifically,with a proper dark pathway,QST and ESG between any two qubits can be achieved without decoupling the others,which simplifies experimental demonstrations.Meanwhile,ESG among all qubits can also be realized in a single step.In addition,our scheme can be implemented in many quantum systems,and we illustrate its implementation on superconducting quantum circuits.Therefore,we propose a powerful strategy for selective quantum manipulation,which is promising in cavity coupled quantum systems and could find many convenient applications in quantum information processing.