arXiv subjects

Xin Ji

Publications and source records attributed to Xin Ji.

24 records · Page 2Linked to original sources

arXiv2014

Shortcuts to adiabatic passage for multiqubit controlled phase gate

We propose an alternative scheme of shortcuts to quantum phase gate in a much shorter time based on the approach of Lewis-Riesenfeld invariants in cavity quantum electronic dynamics (QED) systems. This scheme can be used to perform one-qubit phase gate, two-qubit controlled phase gate and also multiqubit controlled phase gate. The strict numerical simulation for some quantum gates are given, and demonstrate that the total operation time of our scheme is shorter than previous schemes and very robustness against decoherence.

quant-ph↗

arXiv2014

Adiabatic passage for three-dimensional entanglement generation through quantum Zeno dynamics

We propose an adiabatic passage approach to generate two atoms three- dimensional entanglement with the help of quantum Zeno dynamics in a time- dependent interacting field. The atoms are trapped in two spatially separated cavi- ties connected by a fiber, so that the individual addressing is needless. Because the scheme is based on the resonant interaction, the time required to generate entangle- ment is greatly shortened. Since the fields remain in vacuum state and all the atoms are in the ground states, the losses due to the excitation of photons and the spon- taneous transition of atoms are suppressed efficiently compared with the dispersive protocols. Numerical simulation results show that the scheme is robust against the decoherences caused by the cavity decay and atomic spontaneous emission. Addi- tionally, the scheme can be generalized to generate N-atom three-dimensional en- tanglement and high-dimensional entanglement for two spatially separated atoms.

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arXiv2014

Generation of atomic NOON states via adiabatic passage

We propose a scheme for generating atomic NOON states via adiabatic passage. In the scheme, a double $Λ$-type three-level atom is trapped in a bimodal cavity and two sets of $Λ$-type three-level atoms are translated into and outside of two single mode cavities respectively. The three cavities connected by optical fibres are always in vacuum states. After a series of operations and suitable interaction time, we can obtain arbitrary large-$n$ NOON states of two sets of $Λ$-type three-level atoms in distant cavities by performing a single projective measurement on the double $Λ$-type three-level atom. Due to adiabatic elimination of atomic excited states and the application of adiabatic passage, our scheme is robust against the spontaneous emissions of atoms, the decays of fibres and cavities photon leakage. So the scheme has a high fidelity and feasibility under the current available techniques.

quant-ph↗

arXiv2014

Preparation of Knill-Lafamme-Milburn states based on superconducting qutrits

We propose two schemes for generating the Knill-Lafamme-Milburn (KLM) states of two distant polar molecules (PMs) ensembles respectively in two transmission-line resonators (TLRs) connected by a superconducting charge qutrit (SCQ), and of two SCQs in a TLR, respectively. Both of the schemes are robust against photon decay due to the virtual excitations of the microwave photons of the TLRs, and the spontaneous emission can be suppressed owing to the virtual transitions of the SCQs in the second scheme. In addition, the schemes have high controllability and feasibility under the current available techniques.

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arXiv2006

Improving the security of multiparty quantum secret splitting and quantum state sharing

A protocol for multiparty quantum secret splitting (MQSS) with an ordered $N$ Einstein-Podolsky-Rosen (EPR) pairs and Bell state measurements is recently proposed by Deng {\rm et al.} [Phys. Lett. A 354(2006)190]. We analyzed the security of the protocol and found that this protocol is secure for any other eavesdropper except for the agent Bob who adopts intercept-and-resend attack. Bob can obtain all the information of Alice's alone without being found. We also propose an improved version of the MQSS protocol.

quant-ph↗

arXiv2006

Three-party quantum secure direct communication based on Greenberger-Horne-Zeilinger states

We present a three-party simultaneous quantum secure direct communication (QSDC) scheme by using Greenberger-Horne-Zeilinger (GHZ) states. This scheme can be directly generalized to $N$-party QSDC by using $n$-particle GHZ states. We show that the many-party simultaneous QSDC scheme is secure not only against the intercept-and-resend attack but also against the disturbance attack.

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