Phonon self-energy with layered anisotropy: Strong coupling finite temperature and impurities

1996 ◽  
Vol 74 (3-4) ◽  
pp. 159-171
Author(s):  
C. Jiang ◽  
J. P. Carbotte
Keyword(s):  
Superconducting State ◽  
Free Electron ◽  
Finite Temperature ◽  
Cylindrical Symmetry ◽  
Zero Temperature ◽  
Impurity Effects ◽  
Self Energy ◽  
Real Frequency ◽  
Coupling Strengths ◽  
Frequency Axis

We present a generalized, real frequency axis, Eliashberg formulation for the change in phonon self energy on entering the superconducting state which is valid for a solid with layered anisotropy. For simplicity, we assume free electron isotropic propagation in the planes with a hopping probability from plane to plane and cylindrical symmetry. Numerical results are given, at zero temperature, for different amounts of anisotropy and coupling strengths. Finite temperature and impurity effects are also considered.

Cutkosky rules and decay rates at finite temperature

1986 ◽  
Vol 64 (5) ◽  
pp. 602-605
Author(s):  
R. L. Kobes
Keyword(s):  
Finite Temperature ◽  
Temperature Effects ◽  
Decay Rates ◽  
Zero Temperature ◽  
Self Energy

In this paper we outline some recent results concerning the generalization of the Cutkosky or cutting rules to include temperature effects. Differences between these rules and those at zero temperature are illustrated by the correspondence between decay rates and imaginary parts of self-energy graphs.

Damping of spin waves in high-Tc superconductors in the spin polaron formulation

2018 ◽  
Vol 32 (15) ◽  
pp. 1850190 ◽  
Author(s):  
Perkins Jon Ong ◽  
Danilo M. Yanga
Keyword(s):  
Green’S Function ◽  
Spin Wave ◽  
Green's Function ◽  
Finite Temperature ◽  
Spin Waves ◽  
Low Frequency ◽  
Hard Core ◽  
Spin Polaron ◽  
Zero Temperature ◽  
Self Energy

The damping of spin waves in high-T[Formula: see text] superconductors is investigated in this paper. We use the spin polaron formulation in the finite temperature (Matsubara) Green’s function method in a representation, where holes are described as spinless fermions (holons) and spins as normal bosons characterized by the hard-core bosonic operators in accordance with the Holstein–Primakoff transformation. The interaction of holes with spin waves is then described by a Hamiltonian, which resembles the conventional polaron problem and came to be known as the spin polaron Hamiltonian. The rate of the damping of spin waves is then obtained from the self-energy term of the spin wave Green’s function at finite temperature. In the limit of zero temperature and low frequency, the spin wave damping was subsequently determined. We evaluated the same quantity by analytic continuation to get the zero temperature result.

Review of the holographic Lifshitz theory

2014 ◽  
Vol 29 (24) ◽  
pp. 1430049 ◽  
Author(s):  
Chanyong Park
Keyword(s):  
Field Theory ◽  
Finite Temperature ◽  
Quasinormal Mode ◽  
Thermodynamic Quantities ◽  
Black Brane ◽  
Zero Temperature ◽  
Hydrodynamic Properties ◽  
Relativistic Field ◽  
Thermal Entropy ◽  
Lifshitz Theory

We review interesting results achieved in recent studies on the holographic Lifshitz field theory. The holographic Lifshitz field theory at finite temperature is described by a Lifshitz black brane geometry. The holographic renormalization together with the regularity of the background metric allows to reproduce thermodynamic quantities of the dual Lifshitz field theory where the Bekenstein–Hawking entropy appears as the renormalized thermal entropy. All results satisfy the desired black brane thermodynamics. In addition, hydrodynamic properties are further reviewed in which the holographic retarded Green functions of the current and momentum operators are studied. In a nonrelativistic Lifshitz field theory, intriguingly, there exists a massive quasinormal mode at finite temperature whose effective mass is linearly proportional to temperature. Even at zero temperature and in the nonzero momentum limit, a quasinormal mode still remains unlike the dual relativistic field theory. Finally, we account for how adding impurity modifies the electric property of the nonrelativistic Lifshitz theory.

THE SPECIFIC HEAT OF A FERMI GAS AT LOW TEMPERATURE: A CLOSER LOOK AT THE lnT BEHAVIOR

1999 ◽  
Vol 13 (28) ◽  
pp. 3357-3367 ◽  
Author(s):  
A. REBEI ◽  
W. N. G. HITCHON
Keyword(s):  
Low Temperature ◽  
Specific Heat ◽  
Finite Temperature ◽  
Thermodynamic Potential ◽  
Fermi Gas ◽  
Zero Temperature

At finite temperature, a Fermi gas can have states that simultaneously hold a particle and a hole with a finite probability. This gives rise to a new set of diagrams that are absent at zero temperature. The so called "anomalous" diagram is just one of the new diagrams. We have already studied the contribution of these new diagrams to the thermodynamic potential (Phys. Lett.A224, 127 (1996)). Here we continue that work and calculate their effect on the specific heat. We will also calculate the finite temperature contribution of the ring diagrams. We conclude that the ln T behavior of the specific heat due to exchange gets canceled by the new contribution of the new diagrams, and that screening is not essential to resolve this anomaly.

scholarly journals The pion quasiparticle in the low-temperature phase of QCD

2018 ◽  
Vol 175 ◽  
pp. 07045
Author(s):  
Bastian B. Brandt ◽  
Anthony Francis ◽  
Harvey B. Meyer ◽  
Daniel Robaina ◽  
Kai Zapp
Keyword(s):  
Low Temperature ◽  
Finite Temperature ◽  
Quark Mass ◽  
Pion Mass ◽  
Effective Theory ◽  
Temperature Phase ◽  
Zero Temperature ◽  
Low Temperature Phase

We extend our previous studies [PhysRevD.90.054509, PhysRevD.92.094510] of the pion quasiparticle in the low-temperature phase of two-flavor QCD with support from chiral effective theory. This includes the analysis performed on a finite temperature ensemble of size 20 × 643 at T ≈ 151MeV and a lighter zero-temperature pion mass mπ ≈ 185 MeV. Furthermore, we investigate the Gell-Mann–Oakes-Renner relation at finite temperature and the Dey-Eletsky-Ioffe mixing theorem at finite quark mass.

scholarly journals RKKY Interaction in Graphene at Finite Temperature

2019 ◽  
Author(s):  
Eugene Kogan
Keyword(s):  
Finite Temperature ◽  
Thermodynamic Potential ◽  
Real Space ◽  
Magnetic Impurities ◽  
Zero Temperature ◽  
Rkky Interaction ◽  
Imaginary Time ◽  
Direct Evaluation ◽  
Time Representation ◽  
Short Notice

In our publication from 8 years ago1 we calculated RKKY interaction between two magnetic impurities in graphene. The consideration was based on the perturbation theory for the thermodynamic potential in the imaginary time representation and direct evaluation of real space spin susceptibility. Only the case of zero temperature was considered. We show in this short notice that the approach can be easily generalized to the case of finite temperature.

QUANTUM MAGNETIC VORTICES AT FINITE TEMPERATURE IN (3 + 1)-D

2000 ◽  
Vol 15 (11n12) ◽  
pp. 731-735
Author(s):  
E. C. MARINO ◽  
D. G. G. SASAKI
Keyword(s):  
Correlation Function ◽  
Correlation Functions ◽  
Large Distance ◽  
Finite Temperature ◽  
Higgs Model ◽  
Magnetic Vortex ◽  
Zero Temperature ◽  
Magnetic Vortices ◽  
Vortex Lines ◽  
Distance Behavior

We study the effect of a finite temperature on the correlation function of quantum magnetic vortex lines in the framework of the (3 + 1)-dimensional Abelian Higgs model. The vortex energy is inferred from the large distance behavior of these correlation functions. For large straight vortices of length L, we obtain that the energy is proportional to TL2 differently from the zero temperature result which is proportional to L. The case of closed strings is also analyzed. For T = 0, we evaluate the correlation function and energy of a large ring. Finite closed vortices do not exist as genuine excitations for any temperature.

Impurity Effects on the Superconducting State with a Nodeless Gap in the t-J Model

1999 ◽  
pp. 331-334
Author(s):  
Hiroki Tsuchiura ◽  
Yukio Tanaka ◽  
Masao Ogata ◽  
Satoshi Kaskeava
Keyword(s):  
Superconducting State ◽  
Impurity Effects
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