Search results for "cavity quantum electrodynamic"
showing 10 items of 70 documents
Dynamical quantum repeater using cavity-QED and optical coherent states
2013
In the framework of cavity QED, we propose a quantum repeater scheme that uses coherent light and atoms coupled to optical cavities. In contrast to conventional schemes, we exploit solely the cavity QED evolution for the entire quantum repeater scheme and, thus, avoid any explicit execution of quantum logical gates. The entanglement distribution between the repeater nodes is realized with the help of pulses of coherent light interacting with the atom-cavity system in each repeater node. In our previous paper [D. Gonta and P. van Loock, Phys. Rev. A 86, 052312 (2012)], we already proposed a dynamical protocol to purify a bipartite entangled state using the evolution of atomic chains coupled …
Entangling N high-Q cavities
2004
A new conditional scheme for generating maximally entangled states of N spatially separated high-Q cavities is reported. The method is based on the passage of one atom only through all the N cavities. The unavoidable presence of fluctuations in the atom-cavity interaction times is carefully taken into account. The possibility of successfully implementing our proposal against cavity losses and atomic spontaneous decay is moreover discussed.
Teleportation of atomic states via position measurements
2007
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.
Unitary decoupling treatment of a quadratic bimodal cavity quantum electrodynamics model
2013
We consider a two-photon quantum model of radiation–matter interaction between a single two-level atom and a degenerate bimodal high-Q cavity field. Within this tripartite system, the explicit construction of two collective radiation modes, one of which is freely evolving and the other one quadratically coupled to the matter subsystem, is reported. The meaning and advantages of such a decoupling treatment are carefully discussed.
Génération et interfaçage de lumière à photon unique et contrôle de la dynamique atomique ultra-rapide pour l’information quantique
2010
We develop a robust and realistic mechanism for the generation of indistinguishable single-photon (SP) pulses with identical frequency and polarization. They are produced on demand from a coupled double-Raman atom-cavity system driven by a sequence of laser pump pulses. This scheme features a high efficiency, the ability to produce a sequence of narrow-band SP pulses with a delay determined only by the pump repetition rate, and simplicity of the system free from complications such as repumping process and environmental dephasing. We propose and analyze a simple scheme of parametric frequency conversion for optical quantum information in cold atomic ensembles. Its remarkable properties are m…
Effects of an environment on a cavity-quantum-electrodynamics system controlled by bichromatic adiabatic passage
2012
International audience; We present a theoretical investigation of a cavity-QED system controlled by bichromatic adiabatic passage in a dissipative environment. We analyze the production of a controlled Fock state in the cavity by a traveling atom simultaneously coupled by a laser field, and the leakage of the corresponding photons from the cavity.
Quantum Computing with Trapped Charged Particles
2009
The concept of quantum computing has no clear cut origin. It emerged from combinations of information theory and quantum mechanical concepts. A decisive step was taken by Feynman [414, 415] who considered the possibility of universal simulation, a quantum system which could simulate the physical behavior of any other. Feynman gave arguments which suggested that quantum evolution could be used to compute certain problems more efficiently than any classical computer. His device may be considered as not sufficiently specified to be called a computer. The next important step was taken in 1985 by Deutsch [310]. His proposal is generally considered to represent the first blueprint for a quantum c…
Quantum-state manipulation via quantum nondemolition measurements in a two-dimensional trapped ion
2001
The quantum nondemolition measurement is applied to a two-dimensional (2D) trapped-ion model in which two laser beams drive the corresponding vibrational motions and are carrier resonant with the two-level system of the ion. The information about the ionic vibrational energy can be detected by the occupation probability of the internal electronic level. The substantial difference of the 2D model from the one-dimensional one is that two orthogonal beams have a fixed phase shift instead of statistical independence. As a result, the atomic Rabi oscillation is involved in the coherent superposition of two sub-Rabi oscillations induced by the corresponding driving beams. This means that, in the …
Quantum Nondemolition Measurement and Quantum State Manipulation in Two Dimensional Trapped Ion
2001
An extension of QNDmeasuremen t of the vibrational energy of the trapped ion from one dimensional case to the bidimensional one is presented. Our approach exploits the fixed phase difference existing between the two orthogonal and appropriately configured classical laser beams determining the vibronic coupling. We in fact show that this phase difference may play the role of an adjustable external parameter which allows to optimize the measurement scheme itself in terms of both precision and sensitivity. Our proposal provides a cooling method for the trapped ion from the vibrational thermal state. Due to the coherent superposition of two sub Rabi oscillations, the Rabi frequency degeneration…
Quantum noise properties of cavity solitons
2006
General method for studying quantum fluctuations of dissipative structures formed in nonlinear optical cavities is presented. Application to cavity soliton supported by degenerate optical parametric oscillator is presented. Squeezing and intensity fluctuations spectra are discussed.