scholarly journals Zero-temperature localization in a sub-Ohmic spin-boson model investigated by an extended hierarchy equation of motion

2017 ◽  
Vol 95 (21) ◽  
Author(s):  
Chenru Duan ◽  
Zhoufei Tang ◽  
Jianshu Cao ◽  
Jianlan Wu
Keyword(s):  
Equation Of Motion ◽  
Zero Temperature ◽  
Boson Model

Nonequilibrium Density of State of a Kondo Dot Coupled to Luttinger Liquid

2012 ◽  
Vol 622-623 ◽  
pp. 1826-1829
Author(s):  
Kai Hua Yang ◽  
Yang Chen ◽  
Bei Yun Liu ◽  
Xian He
Keyword(s):  
Density Of States ◽  
Bias Voltage ◽  
Strong Interaction ◽  
Luttinger Liquid ◽  
Equation Of Motion ◽  
Green Functions ◽  
Zero Temperature ◽  
Density Of State ◽  
Weakly Coupled ◽  
Kondo Physics

We theoretically investigate the nonequilibrium density of states (DOS) of a Kondo dot weakly coupled to Luttinger liquid leads by using the equation-of-motion technique of non-equilibrium Green functions. The joint effects of large bias voltage and moderately strong intralead interactions results in nontrivial modifications of the Kondo peak in the DOS. The DOS exhibits a two-channel Kondo physics for moderately strong interaction in the leads at zero temperature.

Zero-temperature equation-of-motion of electron pair in the BCS theory of superconductivity

1996 ◽  
Vol 74 (6) ◽  
pp. 1106-1115
Author(s):  
Akitomo Tachibana
Keyword(s):  
Hilbert Space ◽  
Density Functional ◽  
Electron Pair ◽  
Equation Of Motion ◽  
Real Space ◽  
Bcs Theory ◽  
Zero Temperature ◽  
Functional Theory ◽  
Theory Of Superconductivity ◽  
Pair Function

By projecting the BCS ground state of superconducting electron condensate on the N-electron Hilbert space, a real-space equation-of-motion is obtained for the electron pair function [Formula: see text] at absolute zero temperature (T = 0):[Formula: see text]where ρN−2 denotes electron density of the (N – 2)-electron condensate given as[Formula: see text]Since the exchange-correlation potential is given as an explicit functional of electron density, this equation represents the fundamental working equation for the new density functional theory of superconductivity. The 2nd-order density matrix ΓN(1, 2|1′, 2′) projected on the N-electron Hilbert space satisfies[Formula: see text]so that asymptotically[Formula: see text]where [Formula: see text] denotes the center-of-mass coordinate of electrons e1and e2; this is considered the ODLRO (off-diagonal long-range order) at T = 0 projected on the N-electron Hilbert space. A new attractive potential analysis for the two-electron scattering problem (A. Tachibana, Bull. Chem. Soc. Jpn. 66, 3319 (1993); Int. J. Quantum Chem. 49, 625 (1994)) is straightforwardly applicable to the present equation-of-motion, and we can also plug in the vibronic interaction for the enhancement of the attractive force. Our approach is purely mathematical and basic, restricted merely at T = 0, but proves to serve as a real-space analysis of the pair function itself. Key words: equation-of-motion of electron pair, BCS theory, superconductivity, electron pair function, density functional theory.

scholarly journals Non-Markovian effects in the spin-boson model at zero temperature

2021 ◽  
Vol 104 (1) ◽  
Author(s):  
S. Wenderoth ◽  
H.-P. Breuer ◽  
M. Thoss
Keyword(s):  
Zero Temperature ◽  
Boson Model

SUPERCONDUCTOR-INSULATOR TRANSITIONS IN TWO DIMENSIONS

1994 ◽  
Vol 08 (05) ◽  
pp. 277-300 ◽  
Author(s):  
Y. LIU ◽  
A.M. GOLDMAN
Keyword(s):  
Quantum Phase Transitions ◽  
Two Dimensions ◽  
Current Status ◽  
Zero Field ◽  
Zero Temperature ◽  
Limiting Behavior ◽  
Temperature Resistance ◽  
New Class ◽  
Boson Model ◽  
Field Transition

The current status of the experimental study of the superconductor-to-insulator transition is reviewed for systems which are two-dimensional and nominally homogeneous. Interest in this problem has been heightened by the prospect that the transition may be representative of a new class of quantum phase transitions at zero temperature. An ubiquitous feature of the experiments is that films, depending on their properties, or the value of an applied magnetic field, exhibit either insulating or superconducting behavior in the limit of zero temperature. In particular, there appears to exist a limiting behavior which is associated with a finite zero-temperature resistance. In the case of the zero-field transition the value of the limiting resistance may be universal and very close to h/4e2, the quantum resistance for pairs. The experimental results on both the zero- and finite-field transitions will be reviewed and their implications for a particular theoretical picture, the dirty boson model, will be discussed. It has been argued that this model is relevant to the superconductor-insulator transitions.

Extended hierarchy equation of motion for the spin-boson model

2015 ◽  
Vol 143 (22) ◽  
pp. 224112 ◽  
Author(s):  
Zhoufei Tang ◽  
Xiaolong Ouyang ◽  
Zhihao Gong ◽  
Haobin Wang ◽  
Jianlan Wu
Keyword(s):  
Equation Of Motion ◽  
Boson Model
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