Phase correlation of ensemble of quantum emitters and timed Dicke state

2016 ◽  
Vol 30 (21) ◽  
pp. 1650146
Author(s):  
Jae Seok Yoon ◽  
Suc-Kyoung Hong ◽  
Seog Woo Nam ◽  
Hyung Jin Yang
Keyword(s):  
Time Evolution ◽  
Spontaneous Emission ◽  
Weak Coupling ◽  
Phase Correlation ◽  
Weak Coupling Regime ◽  
Effective Coupling ◽  
Dicke States ◽  
Quantum Emitters

We study the phase-correlated state which is introduced by the instantaneous excitation of an ensemble of identical two-level quantum emitters and its relation with the Dicke states. Under weak coupling regime, the time evolution of the phase-correlated system of the emitters is also derived to see the characteristics of the collective spontaneous emission of the emitters. It is found that the effective coupling of the ensemble in the phase-correlated state with the emitted field is directly determined by the collective phase of the system. Hence, the collective phase is considered for several specified distributions in brief.

Anomalies in Strongly Coupled Harmonic Quantum Brownian Motion

2013 ◽  
Vol 20 (01) ◽  
pp. 1350002 ◽  
Author(s):  
F. Giraldi ◽  
F. Petruccione
Keyword(s):  
Time Evolution ◽  
Power Law ◽  
Weak Coupling ◽  
Inverse Power ◽  
Strong Coupling Regime ◽  
Weak Coupling Regime ◽  
Spectral Densities ◽  
Inverse Power Law ◽  
Critical Configurations ◽  
Long Time

The exact dynamics of a quantum damped harmonic oscillator coupled to a reservoir of boson modes has been formally described in terms of the coupling function, both in weak and strong coupling regime. In this scenario, we provide a further description of the exact dynamics through integral transforms. We focus on a special class of spectral densities, sub-ohmic at low frequencies, and including integrable divergencies referred to as photonic band gaps. The Drude form of the spectral densities is recovered as upper limit. Starting from special distributions of coherent states as external reservoir, the exact time evolution, described through Fox H-functions, shows long time inverse power law decays, departing from the exponential-like relaxations obtained for the Drude model. Different from the weak coupling regime, in the sub-ohmic condition, undamped oscillations plus inverse power law relaxations appear in the long time evolution of the observables position and momentum. Under the same condition, the number of excitations shows trapping of the population of the excited levels and oscillations enveloped in inverse power law relaxations. Similarly to the weak coupling regime, critical configurations give arbitrarily slow relaxations useful for the control of the dynamics. If compared to the value obtained in weak coupling condition, for strong couplings the critical frequency is enhanced by a factor 4.

Shared-mode assisted resonant energy transfer in the weak coupling regime

2009 ◽  
Vol 130 (21) ◽  
pp. 214505 ◽  
Author(s):  
E. Hennebicq ◽  
D. Beljonne ◽  
C. Curutchet ◽  
G. D. Scholes ◽  
R. J. Silbey
Keyword(s):  
Energy Transfer ◽  
Weak Coupling ◽  
Weak Coupling Regime ◽  
Resonant Energy ◽  
Resonant Energy Transfer

ENERGY BAND OVERLAPPING IN HIGH-Tc SUPERCONDUCTORS

1996 ◽  
Vol 10 (30) ◽  
pp. 1483-1490 ◽  
Author(s):  
M. MORENO ◽  
R. M. MÉNDEZ-MORENO ◽  
M. A. ORTIZ ◽  
S. OROZCO
Keyword(s):  
Weak Coupling ◽  
Cuprate Superconductors ◽  
Weak Coupling Limit ◽  
Band Model ◽  
Coupling Constant ◽  
High Tc Superconductors ◽  
Energy Bands ◽  
Effective Coupling ◽  
High Tc ◽  
Two Band Model

Multi-band superconductors are analyzed and the relevance of overlapping energy bands to the high-T c of these materials is studied. Within the BCS framework, a two band model with generalized Fermi surface topologies is developed. Values of the overlapped occupancy parameters for typical cuprate superconductors are obtained as a function of the ratio R and the effective coupling constant, λ, in the weak-coupling limit. The overlap scale is of the order or lower than the cutoff (Debye) energy. The typical behavior of the isotope effect is obtained. As these superconductors have transition temperatures above the phonon barrier, the results of this approach are important to the generic understanding of the high-T c superconducting mechanism.

Transition from strong to weak coupling regime with lowering Tc in Tl2Ba2CuO6+x

1994 ◽  
Vol 235-240 ◽  
pp. 1613-1614
Author(s):  
O.M. Vyaselev ◽  
N.N. Kolesnikov ◽  
I.F. Schegolev
Keyword(s):  
Weak Coupling ◽  
Weak Coupling Regime

Finite-dimensional approximation of the scattering matrix

1986 ◽  
Vol 64 (5) ◽  
pp. 611-616 ◽  
Author(s):  
Helmut Kröger ◽  
Anais Smailagic ◽  
Ralph Girard
Keyword(s):  
Weak Coupling ◽  
Weak Coupling Regime ◽  
S Wave ◽  
Proton Proton ◽  
Time Evolution Operator ◽  
Finite Dimensional Approximation ◽  
Finite Dimensional ◽  
Dimensional Approximation ◽  
S Matrix ◽  
Computer Calculations

A finite-dimensional nonperturbative approximation scheme of the time-evolution operator and the S matrix for relativistic field theories is discussed. It is amenable to computer calculations. Parallels with lattice-field theory are drawn. The method is outlined for the ϕ4 theory. Equivalence to standard perturbation theory in the weak-coupling regime is obtained in the limit of the approximation parameters. The method is tested numerically for nonrelativistic proton–proton s-wave scattering and the the ϕ4 model in the weak-coupling regime in 1 + 1 dimensions. In both examples, convergence to the reference solution is found.

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