Browsing by Author "Latha, K. V. P."

Now showing 1 - 5 of 5

Nonequilibrium occupation number and charge susceptibility of a resonance level close to a dissipative quantum phase transition
(2010-08-30)
Chung, Chung-Hou
;
Latha, K. V. P.
;
電子物理學系
;
Department of Electrophysics
Based on the recent paper [Phys. Rev. Lett. 102, 216803 (2009)], we study the nonequilibrium occupation number n(d) and charge susceptibility chi of a resonance level close to dissipative quantum phase transition of the Kosterlitz-Thouless (KT) type between a delocalized phase for weak dissipation and a localized phase for strong dissipation. The resonance level is coupled to two spinless fermionic baths with a finite bias voltage and an Ohmic bosonic bath representing the dissipative environment. The system is equivalent to an effective anisotropic Kondo model out of equilibrium. Within the nonequilibrium renormalization-group approach, we calculate nonequilibrium magnetization M and spin susceptibility chi in the effective Kondo model, corresponding to 2n(d)-1 and chi of a resonance level, respectively. We demonstrate the smearing of the KT transition in the nonequilibrium magnetization M as a function of the effective anisotropic Kondo couplings, in contrast to a perfect jump in M at the transition in equilibrium. In the limit of large bias voltages, we find M and chi at the KT transition and in the localized phase show deviations from the equilibrium Curie-law behavior. As the system gets deeper in the localized phase, both n(d)-1/2 and chi decrease more rapidly to zero with increasing bias voltages.
Relativistic coupled-cluster calculations of (20)Ne, (40)Ar, (84)Kr, and (129)Xe: Correlation energies and dipole polarizabilities
(2009-12-01)
Mani, B. K.
;
Latha, K. V. P.
;
Angom, D.
;
電子物理學系
;
Department of Electrophysics
We have carried out a detailed and systematic study of the correlation energies of inert gas atoms Ne, Ar, Kr, and Xe using relativistic many-body perturbation theory and relativistic coupled-cluster theory. In the relativistic coupled-cluster calculations, we implement perturbative triples and include these in the correlation energy calculations. We then calculate the dipole polarizability of the ground states using perturbed coupled-cluster theory.
Relativistic coupled-cluster calculations of Ne-20, Ar-40, Kr-84, and Xe-129: Correlation energies and dipole polarizabilities
(2009-12-01)
Mani, B. K.
;
Latha, K. V. P.
;
Angom, D.
;
電子物理學系
;
Department of Electrophysics
We have carried out a detailed and systematic study of the correlation energies of inert gas atoms Ne, Ar, Kr, and Xe using relativistic many-body perturbation theory and relativistic coupled-cluster theory. In the relativistic coupled-cluster calculations, we implement perturbative triples and include these in the correlation energy calculations. We then calculate the dipole polarizability of the ground states using perturbed coupled-cluster theory.
Tunable Kondo-Luttinger systems far from equilibrium
(2010-09-27)
Chung, C. -H.
;
Latha, K. V. P.
;
Le Hur, K.
;
Vojta, M.
;
Woelfle, P.
We theoretically investigate the nonequilibrium current through a quantum dot coupled to one-dimensional electron leads, utilizing a controlled frequency-dependent renormalization group approach. We compute the nonequilibrium conductance for large bias voltages and address the interplay between decoherence, Kondo entanglement, and Luttinger physics. The combined effect of large bias voltage and strong interactions in the leads, known to stabilize two-channel Kondo physics, results in nontrivial modifications in the conductance. Interestingly, these unusual changes in the conductance persist in the presence of a finite channel asymmetry.
Tunable Kondo-Luttinger systems far from equilibrium
(2010-09-27)
Chung, C. -H.
;
Latha, K. V. P.
;
Le Hur, K.
;
Vojta, M.
;
Woelfle, P.
We theoretically investigate the nonequilibrium current through a quantum dot coupled to one-dimensional electron leads, utilizing a controlled frequency-dependent renormalization group approach. We compute the nonequilibrium conductance for large bias voltages and address the interplay between decoherence, Kondo entanglement, and Luttinger physics. The combined effect of large bias voltage and strong interactions in the leads, known to stabilize two-channel Kondo physics, results in nontrivial modifications in the conductance. Interestingly, these unusual changes in the conductance persist in the presence of a finite channel asymmetry.