Cooling distant atoms into steady entanglement via coupled cavities

2013 ◽  
Vol 13 (3&4) ◽  
pp. 281-289
Author(s):  
Li Tuo Shen ◽  
Xin Yu Chen ◽  
Zhen-Biao Yang ◽  
Huai-Zhi Wu ◽  
Shi-Biao Zheng
Keyword(s):  
Steady State ◽  
Laser Cooling ◽  
Ground State ◽  
Entangled State ◽  
High Fidelity ◽  
Maximally Entangled State ◽  
Coupled Cavities ◽  
Laser Frequencies ◽  
Cavity System ◽  
Coupled Cavity

We propose a scheme for generating steady-state entanglement between two distant atomic qubits in the coupled-cavity system via laser cooling. With suitable choice of the laser frequencies, the target entangled state is the only ground state that is not excited by the lasers due to large detunings. The laser excitations of other ground states, together with dissipative processes, drive the system to the target state which is the unique steady state of the system. Numerical simulation shows that the maximally entangled state with high fidelity can be produced with presently available cooperativity.

GENERATION OF AN EPR PAIR OF ATOMS IN COUPLED CAVITIES SYSTEM VIA AN OPTICAL FIBER

2008 ◽  
Vol 06 (05) ◽  
pp. 1021-1031 ◽  
Author(s):  
B. F. C. YABU-UTI ◽  
F. K. NOHAMA ◽  
J. A. ROVERSI
Keyword(s):  
Optical Fiber ◽  
Normal Modes ◽  
Single Mode ◽  
Entangled State ◽  
Strong Coupling Regime ◽  
Cavity Field ◽  
Maximally Entangled State ◽  
Coupled Cavities ◽  
Epr Pair ◽  
Single Mode Cavity

The interaction between identical two-level atoms with a system that consists of two coupled cavities connected by an optical fiber was investigated. With new bosonic operators, the interaction Hamiltonian between the fiber and the cavities can be diagonalized (Pellizzari's model1). In the strong coupling regime (cavity field-fiber), the interaction between atoms and the non-resonant normal modes can be eliminated, simplifying our system to that of one atom interacting with a single-mode cavity. For this interaction, we have analyzed the entanglement between distant atoms. We present two simple procedures to generate two atoms in a maximally entangled state, interacting (i) successively and (ii) simultaneously with the coupled cavities system.

scholarly journals Optimal teleportation via noisy quantum channels without additional qubit resources

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Dong-Gil Im ◽  
Chung-Hyun Lee ◽  
Yosep Kim ◽  
Hyunchul Nha ◽  
M. S. Kim ◽  
...  
Keyword(s):  
Quantum Computing ◽  
Quantum Teleportation ◽  
Quantum Communication ◽  
Quantum Noise ◽  
Single Copy ◽  
Entangled State ◽  
Quantum Network ◽  
Quantum Channels ◽  
Maximally Entangled State ◽  
Near Term

AbstractQuantum teleportation exemplifies how the transmission of quantum information starkly differs from that of classical information and serves as a key protocol for quantum communication and quantum computing. While an ideal teleportation protocol requires noiseless quantum channels to share a pure maximally entangled state, the reality is that shared entanglement is often severely degraded due to various decoherence mechanisms. Although the quantum noise induced by the decoherence is indeed a major obstacle to realizing a near-term quantum network or processor with a limited number of qubits, the methodologies considered thus far to address this issue are resource-intensive. Here, we demonstrate a protocol that allows optimal quantum teleportation via noisy quantum channels without additional qubit resources. By analyzing teleportation in the framework of generalized quantum measurement, we optimize the teleportation protocol for noisy quantum channels. In particular, we experimentally demonstrate that our protocol enables to teleport an unknown qubit even via a single copy of an entangled state under strong decoherence that would otherwise preclude any quantum operation. Our work provides a useful methodology for practically coping with decoherence with a limited number of qubits and paves the way for realizing noisy intermediate-scale quantum computing and quantum communication.

Bell inequality for quNits with binary measurements

2003 ◽  
Vol 3 (2) ◽  
pp. 157-164
Author(s):  
H. Bechmann-Pasquinucci ◽  
N. Gisin
Keyword(s):  
Quantum Cryptography ◽  
Bell Inequality ◽  
The Other ◽  
Entangled State ◽  
Maximally Entangled State ◽  
Von Neumann ◽  
Chsh Inequality ◽  
Intermediate States ◽  
Von Neumann Measurements

We present a generalized Bell inequality for two entangled quNits. On one quNit the choice is between two standard von Neumann measurements, whereas for the other quNit there are N^2 different binary measurements. These binary measurements are related to the intermediate states known from eavesdropping in quantum cryptography. The maximum violation by \sqrt{N} is reached for the maximally entangled state. Moreover, for N=2 it coincides with the familiar CHSH-inequality.

scholarly journals Calculating the Energy Spectrum of Complex Low-Dimensional Heterostructures in the Electric Field

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Svetlana N. Khonina ◽  
Sergey G. Volotovsky ◽  
Sergey I. Kharitonov ◽  
Nikolay L. Kazanskiy
Keyword(s):  
Steady State ◽  
Electric Field ◽  
Ground State ◽  
State Energy ◽  
Airy Functions ◽  
Piecewise Constant ◽  
Matrix Rank ◽  
The Matrix ◽  
Constant Potential ◽  
Low Dimensional

An algorithm for solving the steady-state Schrödinger equation for a complex piecewise-constant potential in the presence of theE-field is developed and implemented. The algorithm is based on the consecutive matching of solutions given by the Airy functions at the band boundaries with the matrix rank increasing by no more than two orders, which enables the characteristic solution to be obtained in the convenient form for search of the roots. The algorithm developed allows valid solutions to be obtained for the electric field magnitudes larger than the ground-state energy level, that is, when the perturbation method is not suitable.

Quantum coherence in a coupled-cavity array

2016 ◽  
Vol 30 (18) ◽  
pp. 1650114
Author(s):  
De-Wei Cao ◽  
Yixin Zhang ◽  
Jicheng Wang ◽  
Zheng-Da Hu
Keyword(s):  
Quantum Coherence ◽  
Qualitative Difference ◽  
Superfluid Transition ◽  
Entropy Measure ◽  
Coupled Cavities ◽  
Initial Correlation ◽  
Dynamical Behaviors ◽  
Level Atom ◽  
Cavity Coupling ◽  
Coupled Cavity

The dynamical properties of quantum coherence in the system of two-coupled-cavities, each of which resonantly interacts with a two-level atom, is investigated via the relative entropy measure. We focus on the coherences for the atom–atom, atom–cavity and cavity–cavity subsystems and find that the dynamical behaviors of these coherences depend largely on the cavity–cavity coupling, which may indicate the Mott insulator-superfluid transition in the thermodynamic limit. We also study the influences of the initial cavity–cavity correlation on the coherences and show that the initial correlation of the cavity–cavity subsystem can enhance the revival ability for the atom–atom and cavity–cavity coherences while reduce that for the atom–cavity coherence. Besides, we demonstrate the qualitative difference of dynamics between coherence and entanglement. Finally, the influences of dissipations including cavity losses and atomic decays on the coherence are explored.

scholarly journals Fluorescent chemosensors for metal ions based on 3-(2-benzoxazol-5-yl)alanine skeleton

2010 ◽  
Vol 8 (3) ◽  
pp. 674-686 ◽  
Author(s):  
Magda Milewska ◽  
Katarzyna Guzow ◽  
Wiesław Wiczk
Keyword(s):  
Steady State ◽  
Fluorescence Spectroscopy ◽  
Metal Ions ◽  
Ground State ◽  
Transition Metal Ions ◽  
Fluorescent Chemosensors ◽  
Time Resolved Fluorescence ◽  
Absorption Bands ◽  
Time Resolved ◽  
Ratiometric Sensors

AbstractThe ability of new chelate ligands, benzoxazol-5-yl-alanine derivatives substituted in position 2 by heteroaromatic substituent, to form complexes with selected metal ions in acetonitrile are studied by means of absorption and steady-state and time-resolved fluorescence spectroscopy. Among the ligands studied, only azaaromatic derivatives form stable complexes with transition metal ions in the ground state. Their absorption bands are bathochromically shifted enabling to use those ligands as ratiometric sensors. The fluorescence of each ligand is quenched by metal ions, however, in the presence of Cd(II) and Zn(II) ions a new red shifted emission band is observed.

EVOLUTION OF ATOM-FIELD PROBABILITY IN A COUPLED CAVITY SYSTEM

2013 ◽  
Vol 22 (03) ◽  
pp. 1350029
Author(s):  
K. V. PRIYESH ◽  
RAMESH BABU THAYYULLATHIL
Keyword(s):  
Coupling Strength ◽  
Probability Amplitude ◽  
Field Coupling ◽  
Level Atom ◽  
Cavity System ◽  
Coupling Strengths ◽  
Field Excitation ◽  
Excitation Probability ◽  
Hopping Strength ◽  
Coupled Cavity

In this paper we have investigated the dynamics of two cavities each with a two-level atom, coupled together with photon hopping. The coupled cavity system is studied in single excitation subspace and the evolution of the atom (field) states probabilities are obtained analytically. The probability amplitude of states executes oscillations with different modes and amplitudes, determined by the coupling strengths. The evolution is examined in detail for different atom field coupling strength, g and field–field hopping strength, A. It is noticed that the exact atomic probability amplitude transfer occurs when g ≪ A with minimal field excitation probability and the period of probability transfer is calculated. In the limit g ≫ A there exists periodic exchange of probability between atom and field inside each cavity and also between cavity 1 and cavity 2. Periodicity of each exchange in this limit also obtained.

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