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We use the approach of "transitionless quantum driving" proposed by Berry to construct shortcuts to the population transfer and the creation of maximal entanglement between two Λ-type atoms based on the cavity quantum electronic dynamics (CQED) system. An effective Hamiltonian is designed by resorting to an auxiliary excited level, a classical driving field and an extra cavity field mode to supplement or substitute the original reference Hamiltonian, and steer the system evolution along its instantaneous eigenstates in an arbitrarily short time, speeding up the rate of population transfer and creation of maximal entanglement between the two atoms inside a cavity. Numerical simulation demonstrates that our shortcuts' performance is robust against the decoherences caused by atomic spontaneous emission and cavity photon leakage.

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We propose a set of novel protocols to remotely prepare a general two-qubit state by joint actions of two separate people who independently share the classical knowledge of the state, without and with quantum control of a supervisor. Various quantum resources are used as the quantum channel. Although the execution complexity differs for different protocols, the total success probability is protocol independent.

We present a three-party quantum secure direct communication protocol by using Greenberg–Horne–Zeilinger (GHZ) states and entanglement swapping. The proposed scheme realizes authorized parties' secure exchange of their respective secret messages simultaneously and directly in a set of devices. We show that the scheme is secure against eavesdropper's commonly used attacks. We also generalize the protocol to the N-party case by using N-partite GHZ states.