Unknown Atomic State Research Articles

State-independent teleportation of an atomic state between two cavities

A scheme is presented for the teleportation of an unknown atomic state between two separated cavities. The scheme involves two interaction-detection cycles and uses resonantly coupled atoms with an additional ground state not coupled to the cavity field. Remarkably, the damping of one basis state is balanced by that of the other basis state and the state with photon loss in the first interaction-detection cycle is eliminated by the second cycle. Therefore, the fidelity of teleportation is independent of the teleported state and insensitive to the atomic spontaneous emission, cavity decay, and detection inefficiency, which is obviously in contrast to the original scheme by Bose et al. Phys. Rev. Lett. 83 5158 (1999).

Teleportation of Unknown Atomic Entangled States Using GHZ Class States

We propose two physical schemes, which can teleport unknown atomic entangled states from user A (Alice) to user B (Bob) via GHZ class states as quantum channel. The two schemes are both based on cavity QED techniques. In the two schemes, teleportation and distillation procedures can be realized simultaneously. The second teleportation scheme is more advantageous than the first one.

Teleportation of atomic states via position measurements

We present a scheme for conditionally teleporting an unknown atomic state in cavity QED, which requires two atoms and one cavity mode. The translational degrees of freedom of the atoms are taken into account using the optical Stern-Gerlach model. We show that successful teleportation with probability 1/2 can be achieved through local measurements of the cavity photon number and atomic positions. Neither direct projection onto highly entangled states nor holonomous interaction-time constraints are required.

Approximate and Conditional Teleportation of an Unknown Atomic State with Dissipative Jaynes–Cummings Model

A scheme for approximately and conditionally teleporting an unknown atomic state in dissipative cavity QED is proposed. It is the extension of the scheme of [Phys. Rev. A 69 (2004) 064302], where the cavity mode decay has not been considered and only a time point of system evolution and the corresponding fidelity implementing the teleportation are given. In fact, the cavity mode decay exists really and must be delt with. In this paper, we investigate the influence from the cavity mode decay on the implementation of the approximate and conditional teleportation by means of the dissipative Jaynes–Cummings model and then show the analytical expression of the fidelity of realization of the teleportation. Alternatively, our scheme does not involve an additional atom, only requiring two atoms and one single-mode cavity.

Scheme for realizing assisted cloning of an unknown two-atom entangled state via cavity QED

This paper proposes a scheme where one can realize quantum cloning of an unknown two-atom entangled state with assistance of a state preparer in cavity QED. The first stage of the scheme requires usual teleportation. In the second stage of the scheme, with the assistance of the preparer, the perfect copies of an unknown atomic entangled state can be produced.

Scheme for teleportation of an unknown atomic state via a cluster state in cavity QED

This paper proposes an experimentally feasible scheme for teleportation of an unknown two-atom entangled state, where a cluster state is used as the quantum channel. This scheme does not need any joint measurement. In addition, the successful probability and fidelity of teleportation can both reach 1.0. The current scheme can be realized within the current experimental technology.

Scheme for Deterministic BSM-Free ControlledTeleportation of Unknown Atomic States

We propose a controlled scheme for teleportation of an arbitrary oneor two atomic state via a driven QED cavity. The scheme does notinvolve the joint Bell-state-measurement BSM and the probabilityof successful teleportation is 1. We show that the original atomicstate cannot be perfectly restored by the receiver without all theagents collaborate and classical communication.

Teleportation of an Unknown Atomic State via Adiabatic Passage

We propose a scheme for teleporting an unknown atomic state viaadiabatic passage. Taking advantage of adiabatic passage, the atom has noprobability of being excited and thus the atomic spontaneous emission issuppressed. We also show that the fidelity can reach 1 under certain condition.

Faithfully probabilistic teleportation of an unknown atomic state and cavity field state with a single measurement

This paper shows that, based on the single-photon JC model depicting the resonant interaction of a two-level atom with a single cavity mode, an unknown atomic state and cavity photon superposition state can be faithfully teleported with only a single measurement. The scheme is probabilistic, its success lies on the event that the sender atom (or the medi-atom, for teleportation of cavity field state) is detected in the higher state. The scheme is in contrast to the previous ones of using a maximally two-particle entangled state as quantum channel.

Generation and concentration of atomic entangled state via adiabatic evolution

Based on the idea of adiabatic evolution, we propose two probabilistic but simple schemes for generating maximally entangled states for two distant atoms and concentrating unknown atomic entangled states. Taking advantage of adiabatic passage, the atoms have no probability of being excited and thus the atomic spontaneous emission is suppressed. Furthermore, in the two schemes accurate adjustment of the interaction time is not required.

EFFICIENT SCHEME FOR TELEPORTATION OF UNKNOWN ATOMIC STATES USING NON-MAXIMALLY ENTANGLED STATES

We propose a feasible scheme for teleporting an unknown atomic state by using non-maximally entangled states in cavity QED. The distinct advantage of the scheme is that, not only can the teleportation and distillation procedure be realized simultaneously, but the scheme is also insensitive to the cavity decay and thermal field with the assistance of a strong classical driving field. In addition, the joint Bell-state measurement can be distinguished via detecting the atomic state.

Reply to comment on ‘Faithful teleportation of an unknown atomic state and a cavity field entangled state without Bell-state measurement’

I give a reply to the comment by Cardoso et al on my recent paper (Yang Z-B 2006 J. Phys. B: At. Mol. Opt. Phys. 39 603).

Comment on ‘Faithful teleportation of an unknown atomic state and a cavity field entangled state without Bell-state measurement’

We consider a protocol recently proposed by Zhen-Biao Yang for teleporting entangled photon states from one bimodal cavity to another. It is shown that the proposed protocol can afford full success probability instead of the 1/4 success probability that the author ascribed to his scheme.

Approximate and Conditional Teleportation of an UnknownAtomic-Entangled State Without Bell-State Measurement

A scheme for approximately and conditionallyteleporting an unknownatomic-entangled state in cavity QED is proposed. It is the novel extensionof the scheme of [Phys. Rev. A 69 (2004) 064302], where thestate to be teleported is an unknown atomic state and where only a timepoint of system evolution and the corresponding fidelity implementing theteleportation are given. In fact, there exists multi-time points and thecorresponding fidelities, which are shown in this paper and then are used torealize the approximate and conditional teleportation of the unknownatomic-entangled state. Naturally, our scheme does not involve theBell-state measurement or an additional atom, which is required in theBell-state measurement, only requiring one single-mode cavity. The schememay be generalized to not only the teleportation of thecavity-mode-entangled-state by means of a single atom but also theteleportation of the unknown trapped-ion-entangled-state in a linear iontrap and the teleportation of the multi-atomic entangled statesincluded in generalized GHZ states.

Quantum state transfer via adiabatic passage

Based on adiabatic passage, we propose a scheme for implementing the quantum transfer of an unknown atomic state. In our scheme, we utilize photons for ideal quantum transmission between two cavities with the successful probability being about 1. Meanwhile, the scheme is robust against the effects of atomic spontaneous emission. It may be useful for transferring quantum information among spatially distant atoms.

Teleportation of atomic entangled states with a thermal cavity

We propose a most simple and experimentally feasible scheme for teleporting unknown atomic entangled states in driven cavity quantum electrodynamics (QED). In our scheme, the joint Bell-state measurement (BSM) is not required, and the successful probability can reach 1.0. Furthermore, the scheme is insensitive to the cavity decay and the thermal field.

A scheme for transferring an unknown atomic entangled state via cavity quantum electrodynamics

In this paper, we propose a scheme for transferring an unknown atomic entangled state via cavity quantum electrodynamics (QED). This scheme, which has a successful probability of 100 percent, does not require Bell-state measurement and performing any operations to reconstruct an initial state. Meanwhile, the scheme only involves atom–field interaction with a large detuning and does not require the transfer of quantum information between the atoms and cavity. Thus the scheme is insensitive to the cavity field states and cavity decay. This scheme can also be extended to transferring an entangled state of n-atom.

Scheme for Teleportation of Unknown Entangled Atomic States viaCavity Decay

We present a physical scheme to teleportan unknown atomic entangled state via cavity decay. In the teleportationprocess, four-particle Greenberger–Horne–Zeilinger (GHZ) state is used asquantum channel, and two unknown entangled atoms and two of four atoms inthe four-particle GHZ state are trapped in four leaky cavities,respectively. Based on the joint detection of the photons leak out from thefour cavities, we can teleport an unknown entangled state to two otherremote atoms with certain probability and high fidelity.

TELEPORTATION WITHOUT JOINT MEASUREMENT IN CAVITY QED

Schemes for the teleporting of the cavity mode state and the unknown atomic state are proposed in cavity quantum electrodynamics (QED) without joint Bell-state measurement (BSM). The presented schemes are implemented with separate atomic measurements instead of any type of joint measurement. The discussion of the scheme indicates that it can be realized by current technologies.

EFFICIENT TELEPORTATION OF UNKNOWN ATOMIC ENTANGLED STATES

We propose a scheme for teleporting unknown atomic entangled states in cavity QED. With the assistance of a strong classical field, the photon number dependent parts in the effective Hamiltonian are canceled. Thus, the scheme is insensitive to both the cavity decay and the thermal field. In addition, our scheme does not require the Bell-state measurement directly and the success probability can reach 1.0 in our scheme.