scholarly journals Two-loop self-energy and multiple scattering at finite temperature

2001 ◽  
Vol 64 (4) ◽  
Author(s):  
J. I. Kapusta ◽  
S. M. H. Wong
Keyword(s):  
Multiple Scattering ◽  
Finite Temperature ◽  
Self Energy

scholarly journals Identification of non-Fermi liquid fermionic self-energy from quantum Monte Carlo data

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Xiao Yan Xu ◽  
Avraham Klein ◽  
Kai Sun ◽  
Andrey V. Chubukov ◽  
Zi Yang Meng
Keyword(s):  
Monte Carlo ◽  
Finite Temperature ◽  
Quantum Monte Carlo ◽  
Fermi Liquid ◽  
Quantum Critical Point ◽  
Critical Metals ◽  
Monte Carlo Data ◽  
Low Frequencies ◽  
Self Energy ◽  
Quantum Critical

Abstract Quantum Monte Carlo (QMC) simulations of correlated electron systems provide unbiased information about system behavior at a quantum critical point (QCP) and can verify or disprove the existing theories of non-Fermi liquid (NFL) behavior at a QCP. However, simulations are carried out at a finite temperature, where quantum critical features are masked by finite-temperature effects. Here, we present a theoretical framework within which it is possible to separate thermal and quantum effects and extract the information about NFL physics at T = 0. We demonstrate our method for a specific example of 2D fermions near an Ising ferromagnetic QCP. We show that one can extract from QMC data the zero-temperature form of fermionic self-energy Σ(ω) even though the leading contribution to the self-energy comes from thermal effects. We find that the frequency dependence of Σ(ω) agrees well with the analytic form obtained within the Eliashberg theory of dynamical quantum criticality, and obeys ω2/3 scaling at low frequencies. Our results open up an avenue for QMC studies of quantum critical metals.

Two-loop vacuum polarization in QED at finite temperature

2015 ◽  
Vol 30 (34) ◽  
pp. 1550198
Author(s):  
Mahnaz Q. Haseeb ◽  
Samina S. Masood
Keyword(s):  
Finite Temperature ◽  
Vacuum Polarization ◽  
Renormalization Scheme ◽  
Point Of View ◽  
Electromagnetic Properties ◽  
Electron Mass ◽  
Debye Screening Length ◽  
Coupling Constant ◽  
Self Energy ◽  
Time Formalism

The self-energy of photons at finite temperature is presented, up to the two-loop corrections, using the real-time formalism. The renormalized coupling constant has been derived in a form that is relevant for all the temperature ranges of interest in QED, specifically for the temperatures around [Formula: see text], where [Formula: see text] is the electron mass. Finite temperature modification mainly comes through the hot fermions when [Formula: see text]. We use the calculations for the vacuum polarization to determine the dynamically generated mass of the photon, Debye screening length, and plasma frequency up to order [Formula: see text] as well as the electromagnetic properties of the background medium in the temperature range [Formula: see text]. At higher temperatures, the existing renormalization scheme does not work well because of the increase in the coupling constant. To exactly determine the validity of the renormalization scheme, the higher order calculations are required. The temperature, [Formula: see text], is of specific interest from the point of view of the early universe. Such calculations have also recently acquired significance due to the possibility of producing electron–positron plasma in the laboratory.

scholarly journals Finite temperature gluon self-energy in a class of temporal gauges

2000 ◽  
Vol 61 (12) ◽  
Author(s):  
F. T. Brandt ◽  
J. Frenkel ◽  
F. R. Machado
Keyword(s):  
Finite Temperature ◽  
Self Energy

scholarly journals All Orders Transport Theory from the Multiple Scattering Expansion of the Self-Energy: The Central Cuts

2006 ◽  
Vol 27 (2-3) ◽  
pp. 339-342
Author(s):  
Jean-Sébastien Gagnon ◽  
François Fillion-Gourdeau ◽  
Sangyong Jeon
Keyword(s):  
Multiple Scattering ◽  
Transport Theory ◽  
The Self ◽  
Self Energy

Single-Particle Self-Energy in Many-Body Systems at Finite Temperature

2000 ◽  
Vol 283 (2) ◽  
pp. 308-333 ◽  
Author(s):  
N. Giovanardi ◽  
P. Donati ◽  
P.F. Bortignon ◽  
R.A. Broglia
Keyword(s):  
Single Particle ◽  
Finite Temperature ◽  
Many Body ◽  
Self Energy ◽  
Many Body Systems
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