scholarly journals The BCS Critical Temperature at High Density

2022 ◽  
Vol 25 (1) ◽  
Author(s):  
Joscha Henheik
Keyword(s):  
Critical Temperature ◽  
Asymptotic Formula ◽  
Fermi Surface ◽  
Interaction Potential ◽  
High Density ◽  
Bcs Theory ◽  
Density Limit

AbstractWe investigate the BCS critical temperature $$T_c$$ T c in the high-density limit and derive an asymptotic formula, which strongly depends on the behavior of the interaction potential V on the Fermi-surface. Our results include a rigorous confirmation for the behavior of $$T_c$$ T c at high densities proposed by Langmann et al. (Phys Rev Lett 122:157001, 2019) and identify precise conditions under which superconducting domes arise in BCS theory.

scholarly journals Deformation of the Fermi surface of a spinless two-dimensional electron gas in presence of an anisotropic Coulomb interaction potential

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Orion Ciftja
Keyword(s):  
Fermi Surface ◽  
Coulomb Interaction ◽  
Interaction Potential ◽  
Fermi Liquid ◽  
Energy State ◽  
Electron Gas ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Two Dimensional Electron Gas ◽  
Dimensional Electron Gas

AbstractWe consider the stability of the circular Fermi surface of a two-dimensional electron gas system against an elliptical deformation induced by an anisotropic Coulomb interaction potential. We use the jellium approximation for the neutralizing background and treat the electrons as fully spin-polarized (spinless) particles with a constant isotropic (effective) mass. The anisotropic Coulomb interaction potential considered in this work is inspired from studies of two-dimensional electron gas systems in the quantum Hall regime. We use a Hartree–Fock procedure to obtain analytical results for two special Fermi liquid quantum electronic phases. The first one corresponds to a system with circular Fermi surface while the second one corresponds to a liquid anisotropic phase with a specific elliptical deformation of the Fermi surface that gives rise to the lowest possible potential energy of the system. The results obtained suggest that, for the most general situations, neither of these two Fermi liquid phases represent the lowest energy state of the system within the framework of the family of states considered in this work. The lowest energy phase is one with an optimal elliptical deformation whose specific value is determined by a complex interplay of many factors including the density of the system.

scholarly journals Correlation energy of two electrons in the high-density limit

2009 ◽  
Vol 131 (24) ◽  
pp. 241101 ◽  
Author(s):  
Pierre-François Loos ◽  
Peter M. W. Gill
Keyword(s):  
Correlation Energy ◽  
High Density ◽  
Density Limit

scholarly journals Ising model in the high density limit

1974 ◽  
Vol 36 (4) ◽  
pp. 255-262 ◽  
Author(s):  
Colin J. Thompson
Keyword(s):  
Ising Model ◽  
High Density ◽  
Density Limit

Anomalous reflection properties in high density limit fibril shaped PIC-J aggregates in microcavity structure

2011 ◽  
Vol 8 (2) ◽  
pp. 595-597 ◽  
Author(s):  
Yuki Obara ◽  
Keita Saitoh ◽  
Masaru Oda ◽  
Toshiro Tani
Keyword(s):  
High Density ◽  
Density Limit ◽  
Anomalous Reflection ◽  
J Aggregates

High-Density Limit and Inflation of Matter

2005 ◽  
Vol 95 (19) ◽  
Author(s):  
E. B. Manoukian ◽  
S. Sirininlakul
Keyword(s):  
High Density ◽  
Density Limit

scholarly journals Moiré with flat bands is different

2019 ◽  
Vol 50 (3) ◽  
pp. 24-26
Author(s):  
Tero T. Heikkilä ◽  
Timo Hyart
Keyword(s):  
Critical Temperature ◽  
Fermi Surface ◽  
Room Temperature ◽  
Electronic States ◽  
Bilayer Graphene ◽  
Flat Bands ◽  
Twisted Bilayer Graphene

Recent experimental discoveries of superconductivity and other exotic electronic states in twisted bilayer graphene (TBG) call for a reconsideration of our traditional theories of these states, usually based on the assumption of the presence of a Fermi surface. Here we show how such developments may even help us finding mechanisms of increasing the critical temperature of superconductivity towards the room temperature.

scholarly journals Characterization of the superconducting phase in tellurium hydride at high pressure

2019 ◽  
Vol 33 (16) ◽  
pp. 1950169 ◽  
Author(s):  
Tomasz P. Zemła ◽  
Klaudia M. Szczȩśniak ◽  
Adam Z. Kaczmarek ◽  
Svitlana V. Turchuk
Keyword(s):  
High Pressure ◽  
Critical Temperature ◽  
Strong Coupling ◽  
Superconducting State ◽  
Density Functional ◽  
Superconducting Phase ◽  
Bcs Theory ◽  
Electron Mass ◽  
Eliashberg Equations ◽  
Effective Electron

At present, hydrogen-based compounds constitute one of the most promising classes of materials for applications as phonon-mediated high-temperature superconductors. Herein, the behavior of the superconducting phase in tellurium hydride (HTe) at high pressure (p = 300 GPa) is analyzed in detail, by using the isotropic Migdal–Eliashberg equations. The chosen pressure conditions are considered here as a case study which corresponds to the highest critical temperature value [Formula: see text] in the analyzed material, as determined within recent density functional theory simulations. It is found that the Migdal–Eliashberg formalism, which constitutes a strong-coupling generalization of the Bardeen–Cooper–Schrieffer (BCS) theory, predicts that the critical temperature value ([Formula: see text] K) is higher than previous estimates of the McMillan formula. Further investigations show that the characteristic dimensionless ratios for the thermodynamic critical field, the specific heat for the superconducting state, and the superconducting band gap exceed the limits of the BCS theory. In this context, also the effective electron mass is not equal to the bare electron mass as provided by the BCS theory. On the basis of these findings it is predicted that the strong-coupling and retardation effects play pivotal role in the superconducting phase of HTe at 300 GPa, in agreement with similar theoretical estimates for the sibling hydrogen and hydrogen-based compounds. Hence, it is suggested that the superconducting state in HTe cannot be properly described within the mean-field picture of the BCS theory.

EFFECTIVE THEORY OF BOSONIC SUPERFLUIDS

1994 ◽  
Vol 08 (15) ◽  
pp. 2021-2039 ◽  
Author(s):  
ADRIAAN M.J. SCHAKEL
Keyword(s):  
Critical Temperature ◽  
Weak Coupling ◽  
Particle Number ◽  
Landau Theory ◽  
Effective Theory ◽  
Bcs Theory ◽  
Goldstone Mode ◽  
Zero Temperature ◽  
Temperature Expansion ◽  
High Temperature Expansion

We discuss the effective theory of a bosonic superfluid whose microscopic behavior is described by a nonrelativistic, weak-coupling Φ4 theory in the phase with broken particle number symmetry, both at zero temperature and in the vicinity of the phase transition. In the zero-temperature regime, the theory is governed by the gapless Goldstone mode resulting from the broken .symmetry. Although this mode is gapless, the effective theory turns out to be Gallilei invariant. The regime just below the critical temperature is approached in a high-temperature expansion which is shown to be consistent with the weak-coupling assumption of the theory. We calculate the critical temperature, the co-efficients of the Landau theory, and the finite-temperature sound velocity. A comparison with BCS theory is given.

High-density limit of hot chiral matter

1990 ◽  
Vol 42 (4) ◽  
pp. 1215-1217 ◽  
Author(s):  
Enrique Alvarez ◽  
J. L. F. Barbón ◽  
Agustín Nieto
Keyword(s):  
High Density ◽  
Density Limit
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