Optimal atomic entanglement concentration using coherent-state input–output process in low-Q cavity quantum electrodynamics system

2013 ◽  
Vol 30 (8) ◽  
pp. 2136 ◽  
Author(s):  
Cong Cao ◽  
Chuan Wang ◽  
Ling-yan He ◽  
Xin Tong ◽  
Ming Lei ◽  
...  
Keyword(s):  
Coherent State ◽  
Quantum Electrodynamics ◽  
Cavity Quantum Electrodynamics ◽  
Entanglement Concentration ◽  
Output Process ◽  
Input Output ◽  
Atomic Entanglement

scholarly journals Universal remote quantum computation assisted by the cavity input–output process

2015 ◽  
Vol 471 (2184) ◽  
pp. 20150274 ◽  
Author(s):  
Ming-Xing Luo ◽  
Xiaojun Wang
Keyword(s):  
Quantum Computation ◽  
Quantum Electrodynamics ◽  
Cavity Quantum Electrodynamics ◽  
Output Process ◽  
Input Output ◽  
Toffoli Gate ◽  
Classical Communication ◽  
Optical Cavities ◽  
Proposed Model ◽  
Einstein Podolsky Rosen

Quantum computing may provide potential superiority to solve some difficult problems. We propose a scheme for scalable remote quantum computation based on an interface between the photon and the spin of an electron confined in a quantum dot embedded in a microcavity. By successively interacting auxiliary photon pulses with spins charged in optical cavities, a prototypical quantum controlled–controlled flip gate (Toffoli gate) is achieved on a remote three-spin system using only one Einstein–Podolsky–Rosen entanglement, and local operations and classical communication. Our proposed model is shown to be robust to practical noise and experimental imperfections in current cavity–quantum electrodynamics techniques.

The influence of excitation number of photon-added coherent state field on the entanglement swapping process

2017 ◽  
Vol 31 (27) ◽  
pp. 1750198 ◽  
Author(s):  
M. Soltani ◽  
M. K. Tavassoly ◽  
R. Pakniat
Keyword(s):  
Coherent State ◽  
Quantum Electrodynamics ◽  
Coherent States ◽  
Success Probability ◽  
Entanglement Swapping ◽  
Cavity Quantum Electrodynamics ◽  
Linear Entropy ◽  
Entangled State ◽  
Maximally Entangled State ◽  
Coherent Field

In this paper, we outline a scheme for the entanglement swapping procedure based on cavity quantum electrodynamics using the Jaynes–Cummings model consisting of the coherent and photon-added coherent states. In particular, utilizing the photon-added coherent states ([Formula: see text][Formula: see text][Formula: see text][Formula: see text], where [Formula: see text] is the Glauber coherent state) in the scheme, enables us to investigate the effect of [Formula: see text], i.e., the number of excitations corresponding to the photon-added coherent field on the entanglement swapping process. In the scheme, two two-level atoms [Formula: see text] and [Formula: see text] are initially entangled together, and distinctly two exploited cavity fields [Formula: see text] and [Formula: see text] are prepared in an entangled state (a combination of coherent and photon-added coherent states). Interacting the atom [Formula: see text] with field [Formula: see text] (via the Jaynes–Cummings model) and then making detection on them, transfers the entanglement from the two atoms [Formula: see text], [Formula: see text] and the two fields [Formula: see text], [Formula: see text] to the atom-field “[Formula: see text]-[Formula: see text]”, i.e., entanglement swapping occurs. In the continuation, we pay our attention to the evaluation of the fidelity of the swapped entangled state relative to a suitable maximally entangled state, success probability of the performed detections and linear entropy as the degree of entanglement of the swapped entangled state. It is demonstrated that, an increase in the number of excitations, [Formula: see text], leads to the increment of fidelity as well as the amount of entanglement. According to our numerical results, the maximum values of fidelity (linear entropy) 0.98 (0.46) is obtained for [Formula: see text], however, the maximum value of success probability does not significantly change by increasing [Formula: see text].

Nonlocal entanglement concentration of separate nitrogen-vacancy centers coupling to microtoroidal resonators

2014 ◽  
Vol 14 (1&2) ◽  
pp. 107-121
Author(s):  
Chuan Wang ◽  
Yong Zhang ◽  
Ming Lei ◽  
Guang-sheng Jin ◽  
Hai-qiang Ma ◽  
...  
Keyword(s):  
Nitrogen Vacancy ◽  
Entanglement Concentration ◽  
Entangled State ◽  
Output Process ◽  
Parity Check ◽  
Input Output ◽  
Check Gate ◽  
Nitrogen Vacancy Centers ◽  
Microtoroidal Resonator ◽  
Nonlocal Entanglement

Here we propose two practical protocols to concentrate entanglement between separate nitrogen-vacancy (N-V) centers in less entangled state via coupling to microtoroidal resonators. We construct the parity check gate of the N-V center and microtoroidal resonator systems via the interaction with the ancillary photon input-output process near the microtoroidal resonators. Thus the parity of the N-V center state can be readout by the measurement on the ancillary photon. Then we introduce the parity check operations to entanglement concentration protocols. Considering current techniques, we also discuss the feasibility of our proposal and its experimental challenges.

Manipulation of Quantum Communication Channel via Two-Level Atom Interacting with Caving Fields

2014 ◽  
Vol 571-572 ◽  
pp. 469-472
Author(s):  
Xin Hua Cai ◽  
Jian Jun Nie
Keyword(s):  
Quantum Electrodynamics ◽  
Coherent States ◽  
Communication Channel ◽  
Quantum Communication ◽  
Cavity Quantum Electrodynamics ◽  
Entanglement Concentration ◽  
Field Interaction ◽  
Entangled Coherent State ◽  
Level Atom ◽  
Quantum Communication Channel

Base on the dispersive atom-cavity field interaction, the scheme for preparing the entangled coherent state is discussed. An experimentally feasible protocol for realizing entanglement concentration of the entangled coherent states by using a two-level atom interacting with caving fields is proposed. In this protocol, the entanglement between two coherent states, and , with the same amplitude but a phase difference is utilized as the quantum communication channel. The process of the entanglement concentration is implemented by using a two-level atom interacting with caving fields and two-modes orthogonal states measurement. With the present development of cavity quantum electrodynamics (QED) techniques, the scheme can be achieved.

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