scholarly journals Exact real-time dynamics of single-impurity Anderson model from a single-spin hybridization-expansion

2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Patryk Kubiczek ◽  
Alexey Rubtsov ◽  
Alexander Lichtenstein
Keyword(s):  
Real Time ◽  
Continuous Time ◽  
Quantum Monte Carlo ◽  
Time Dynamics ◽  
Single Spin ◽  
Impurity Model ◽  
Sign Problem ◽  
Spin Polarized ◽  
Anderson Impurity Model ◽  
Long Time

In this work we introduce a modified real-time continuous-time hybridization-expansion quantum Monte Carlo solver for a time-dependent single-orbital Anderson impurity model: CT-1/2-HYB-QMC. In the proposed method the diagrammatic expansion is performed only for one out of the two spin channels, while the resulting effective single-particle problem for the other spin is solved semi-analytically for each expansion diagram. CT-1/2-HYB-QMC alleviates the dynamical sign problem by reducing the order of sampled diagrams and makes it possible to reach twice as long time scales in comparison to the standard CT-HYB method. We illustrate the new solver by calculating an electric current through impurity in paramagnetic and spin-polarized cases.

Biorobots, Nonlinear Dynamics and Perception

2008 ◽  
Vol 58 ◽  
pp. 143-152
Author(s):  
Paolo Arena ◽  
Davide Lombardo ◽  
Luca Patanè
Keyword(s):  
Nonlinear Dynamics ◽  
Real Time ◽  
Continuous Time ◽  
Biologically Inspired ◽  
Time Dynamics ◽  
Nonlinear Network ◽  
Biologically Inspired Robots ◽  
Novel Approach ◽  
Perceptual Control ◽  
Efficient Control

In this contribution a survey on a novel approach to locomotion and perception in biologically inspired robots is presented. The basic electronic architecture for modeling and implementing nonlinear dynamics involved in motion and perceptual control of the robot is the Cellular nonlinear network paradigm. It is shown how this continuous time lattice of neural-like circuits can generate suitable and real-time dynamics for efficient control of multi-actuators moving machines, and also to create the basis for a perceptual control of their behaviors.

ANALYSIS OF GIANT RESONANT PHOTOEMISSION, MAGNETIC X RAY DICHROISM, AND CIRCULAR DICHROISM IN SPIN POLARIZED PHOTOEMISSION FROM CORE STATES OF FERROMAGNETIC NICKEL

1994 ◽  
Vol 08 (06) ◽  
pp. 641-678 ◽  
Author(s):  
G. VAN DER LAAN
Keyword(s):  
Circular Dichroism ◽  
X Ray ◽  
Resonant Photoemission ◽  
Orbital Magnetic Moment ◽  
At Resonance ◽  
Impurity Model ◽  
Spin Polarized ◽  
Anderson Impurity Model ◽  
X Ray Absorption ◽  
Circular Dichroïsm

The strong variations observed in the satellite and multiplet structure of photoemission at resonance with a deep core level and in the circular dichroism and spin resolved photoemission provide an interesting method to determine the electronic structure of correlated materials as well as the possibility to assign the peak structures. Analysis of these effects in the x ray absorption and photoemission of ferromagnetic nickel using an Anderson impurity model suggest that nickel has a ground state with d weights of around 15% d8, 50% d9 and 35% d10, and that its bulk orbital magnetic moment of 0.053 μ B is strongly enhanced at the surface.

scholarly journals Analysis of Real-Time Control Systems using First-Order Continuization

10.29007/8nq6 ◽  
2020 ◽  
Author(s):  
Maximilian Gaukler
Keyword(s):  
Control Systems ◽  
Real Time ◽  
Continuous Time ◽  
Real Time Control ◽  
Control Loops ◽  
Time Dynamics ◽  
First Order ◽  
Time Control ◽  
Formal Framework ◽  
Continuous Time System

Experience Report: Real-Time control systems can be difficult to analyze due to the mixture of discrete-time and continuous-time dynamics. This difficulty is particularly pronounced if the timing is non-periodic, e.g., due to network or execution effects. Still, most control loops behave similar to a purely continuous-time system disturbed by a small discretization error, which is exploited by Bak and Johnson (2015) in the method of Continuization. This paper uncovers limitations of that work and presents an extension, First-Order Continuization, based on a new formal framework that recovers previous results and eases future development.

scholarly journals Numerically exact long-time magnetization dynamics at the nonequilibrium Kondo crossover of the Anderson impurity model

2013 ◽  
Vol 87 (19) ◽  
Author(s):  
Guy Cohen ◽  
Emanuel Gull ◽  
David R. Reichman ◽  
Andrew J. Millis ◽  
Eran Rabani
Keyword(s):  
Magnetization Dynamics ◽  
Impurity Model ◽  
Anderson Impurity Model ◽  
Long Time
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