Basis set sampling in the method of coupled coherent states: Coherent state swarms, trains, and pancakes

2008 ◽  
Vol 128 (5) ◽  
pp. 054102 ◽  
Author(s):  
Dmitrii V. Shalashilin ◽  
Mark S. Child
Keyword(s):  
Coherent State ◽  
Coherent States ◽  
Basis Set

INTERACTION OF MESOSCOPIC JOSEPHSON JUNCTION WITH A SUCCESSIVE SQUEEZED COHERENT FIELD

2000 ◽  
Vol 14 (16) ◽  
pp. 609-618
Author(s):  
V. A. POPESCU
Keyword(s):  
Coherent State ◽  
Josephson Junction ◽  
Coherent States ◽  
Quantum Noise ◽  
Shapiro Steps ◽  
Superconducting Ring ◽  
Coherent Field ◽  
Current Voltage ◽  
Quantum Current ◽  
The Difference

Signal-to-quantum noise ratio for quantum current in mesoscopic Josephson junction of a circular superconducting ring can be improved if the electromagnetic field is in a successive squeezed coherent state. The mesoscopic Josephson junctions can feel the difference between the successive squeezed coherent states and other types of squeezed coherent states because their current–voltage Shapiro steps are different. We compare our method with another procedure for superposition of two squeezed coherent states (a squeezed even coherent state) and consider the effect of different large inductances on the supercurrent.

scholarly journals Common Coherence Witnesses and Common Coherent States

Entropy ◽  
2021 ◽  
Vol 23 (9) ◽  
pp. 1136
Author(s):  
Bang-Hai Wang ◽  
Zi-Heng Ding ◽  
Zhihao Ma ◽  
Shao-Ming Fei
Keyword(s):  
Coherent State ◽  
Coherent States ◽  
State Problem ◽  
Properties And Characterization ◽  
The Common ◽  
High Level

We show the properties and characterization of coherence witnesses. We show methods for constructing coherence witnesses for an arbitrary coherent state. We investigate the problem of finding common coherence witnesses for certain class of states. We show that finitely many different witnesses W1,W2,⋯,Wn can detect some common coherent states if and only if ∑i=1ntiWi is still a witnesses for any nonnegative numbers ti(i=1,2,⋯,n). We show coherent states play the role of high-level witnesses. Thus, the common state problem is changed into the question of when different high-level witnesses (coherent states) can detect the same coherence witnesses. Moreover, we show a coherent state and its robust state have no common coherence witness and give a general way to construct optimal coherence witnesses for any comparable states.

Complete basis set via straight-line coherent-state superpositions

1994 ◽  
Vol 49 (2) ◽  
pp. 1281-1287 ◽  
Author(s):  
P. Adam ◽  
I. Földesi ◽  
J. Janszky
Keyword(s):  
Coherent State ◽  
Basis Set ◽  
Complete Basis ◽  
Straight Line ◽  
Complete Basis Set

scholarly journals Binary Communication with Gazeau–Klauder Coherent States

Entropy ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 201
Author(s):  
Jerzy Dajka ◽  
Jerzy Łuczka
Keyword(s):  
Coherent State ◽  
Optical Communication ◽  
Coherent States ◽  
Error Probability ◽  
Nonlinear Oscillator ◽  
Short Paper ◽  
Trace Distance ◽  
Advantages And Disadvantages

We investigate advantages and disadvantages of using Gazeau–Klauder coherent states for optical communication. In this short paper we show that using an alphabet consisting of coherent Gazeau–Klauder states related to a Kerr-type nonlinear oscillator instead of standard Perelomov coherent states results in lowering of the Helstrom bound for error probability in binary communication. We also discuss trace distance between Gazeau–Klauder coherent states and a standard coherent state as a quantifier of distinguishability of alphabets.

Teleporting the Schrödinger Cat State

1998 ◽  
Vol 12 (29n30) ◽  
pp. 1209-1216 ◽  
Author(s):  
M. H. Y. Moussa ◽  
B. Baseia
Keyword(s):  
Coherent State ◽  
Quantum Channel ◽  
Coherent States ◽  
Joint Measurement ◽  
Bell Basis ◽  
Schrödinger Cat ◽  
Schrodinger Cat State

We present a scheme for the teleportation of a coherent state or a mesoscopic superposition of coherent states — the Schrödinger-cat state. The proposal involves a mesoscopic-correlated state as the quantum channel which is generated through an adaptation of a quantum switch scheme. The required joint measurement performed in a mesoscopic Bell basis is accomplished through a technique for detection of a Schrödinger-cat state "trapped" in a cavity.

On the Squeezing and Displacement of nth-Order

1997 ◽  
Vol 11 (09n10) ◽  
pp. 399-406
Author(s):  
Norton G. de Almeida ◽  
Célia M. A. Dantas
Keyword(s):  
Coherent State ◽  
Coherent States ◽  
Photon Number ◽  
Natural Generalization ◽  
Statistical Properties ◽  
Number Distribution ◽  
Quantum Statistical ◽  
Photon Number Distribution

The norder expressions for the squeezed and coherent states are derived as a natural generalization of the usual squeezed coherent and coherent states. The photon number distribution of n order of squeezed coherent states that are eigenstates of the operators [Formula: see text] is derived. The n order coherent state is a particular case of the states that we are now deriving. Some mathematical and quantum statistical properties of these states are discussed.

COHERENT STATES WITHOUT GROUPS: QUANTIZATION ON NONHOMOGENEOUS MANIFOLDS

1993 ◽  
Vol 08 (18) ◽  
pp. 1735-1738 ◽  
Author(s):  
JOHN R. KLAUDER
Keyword(s):  
Phase Space ◽  
Coherent State ◽  
Wide Class ◽  
Coherent States ◽  
Path Integrals ◽  
Killing Vector ◽  
Single Variable ◽  
Holomorphic Representation ◽  
Representation Spaces ◽  
State Path

A wide class of single-variable holomorphic representation spaces are constructed that are associated with very general sets of coherent states defined without the use of transitively acting groups. These representations and states are used to define coherent-state path integrals involving phase-space manifolds having one Killing vector but a quite general curvature otherwise.

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].

scholarly journals COHERENT STATE OF THE EFFECTIVE MASS HARMONIC OSCILLATOR

2009 ◽  
Vol 24 (17) ◽  
pp. 1343-1353 ◽  
Author(s):  
ATREYEE BISWAS ◽  
BARNANA ROY
Keyword(s):  
Coherent State ◽  
Harmonic Oscillator ◽  
Closed Form ◽  
Effective Mass ◽  
Coherent States ◽  
Mass Function ◽  
Wigner Functions

We construct coherent state of the effective mass harmonic oscillator and examine some of its properties. In particular closed form expressions of coherent states for different choices of the mass function are obtained and it is shown that such states are not in general x - p uncertainty states. We also compute the associated Wigner functions.

WIGNER FUNCTION EVOLUTION OF EXCITED EVEN AND ODD COHERENT STATE IN THERMAL ENVIRONMENT VIA THERMO ENTANGLED APPROACH

2013 ◽  
Vol 27 (23) ◽  
pp. 1350120 ◽  
Author(s):  
HONG-CHUN YUAN ◽  
YE-JUN XU ◽  
LEI CHEN ◽  
XUE-FEN XU
Keyword(s):  
Coherent State ◽  
Wigner Function ◽  
Decay Time ◽  
Arbitrary Number ◽  
Coherent States ◽  
Density Operator ◽  
Thermal Environment ◽  
New Approach ◽  
Non Gaussian ◽  
Analytical Expressions

We adopt a new approach, thermo entangled representation, to study time evolution of density operator in thermal environment. We then investigate the analytical expressions of Wigner function (WF) evolution of arbitrary number excited coherent states (ECSs) and excited even (odd) coherent states (EECSs, EOCSs) in thermal environment, respectively. In addition, their nonclassicality is numerically discussed by exploring the negativity of WF with decay time in thermal channel, respectively. It is found that WF loses its non-Gaussian nature and becomes Gaussian after long times.

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