Fermi level dependence of hydrogen diffusivity in GaN

We review the use of an exact renormalization group equation in quantum field theory and statistical physics. It describes the dependence of the free energy on an infrared cutoff for the quantum or thermal fluctuations. Non-perturbative solutions follow from approximations to the general form of the coarse-grained free energy or effective average action. They interpolate between the microphysical laws and the complex macroscopic phenomena. Our approach yields a simple unified description for O(N )-symmetric scalar models in two, three or four dimensions, covering in particular the critical phenomena for the second-order phase transitions, including the Kosterlitz-Thouless transition and the critical behavior of polymer chains. We compute the aspects of the critical equation of state which are universal for a large variety of physical systems and establish a direct connection between microphysical and critical quantities for a liquid-gas transition. Universal features of first-order phase transitions are studied in the context of scalar matrix models. We show that the quantitative treatment of coarse graining is essential for a detailed estimate of the nucleation rate. We discuss quantum statistics in thermal equilibrium or thermal quantum field theory with fermions and bosons and we describe the high temperature symmetry restoration in quantum field theories with spontaneous symmetry breaking. In particular we explore chiral symmetry breaking and the high temperature or high density chiral phase transition in quantum chromodynamics using models with effective four-fermion interactions.This work is dedicated to the 60th birthday of Franz Wegner. *

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“…which is characterized by asymptotic freedom [115]. The "confinement scale" where the coupling g becomes strong can be associated with k s .…”

Section: A Simple Example: the Quartic Potentialmentioning

confidence: 99%

Non-perturbative renormalization flow in quantum field theory and statistical physics

2002

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“…There is no problem with the limit for the differential equation (2.32) and for the solution Θ + (2.34). Namely, 43) where Ξ + is a solution of…”

Section: 4mentioning

confidence: 99%

Notes on parafermionic QFTs with boundary interaction

Lukyanov

2007

Nuclear Physics B

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The main result of these notes is an analytical expression for the partition function of the circular brane model [1] for arbitrary values of the topological angle. The model has important applications in condensed matter physics. It is related to the dissipative rotator (Ambegaokar-Eckern-Schön) model [2] and describes a "weakly blocked" quantum dot with an infinite number of tunneling channels under a finite gate voltage bias. A numerical check of the analytical solution by means of Monte Carlo simulations has been performed recently in Ref. [3]. To derive the main result we study the so-called boundary parafermionic sine-Gordon model. The latter is of certain interest to condensed matter applications, namely as a toy model for a point junction in the multichannel quantum wire [4].

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“…For d = 2 and N > 2 the effective coupling of the nonlinear σ-model for the Goldstone bosons is given by κ −1 [8]. The universality of the β-function for the nonlinear coupling [88] implies for κ ≫ 1 an asymptotic form (N ≥ 2, d = 2)…”

Section: Kosterlitz-thouless Transition and Essential Scalingmentioning

confidence: 99%

Effective Average Action in Statistical Physics and Quantum Field Theory

Wetterich

2001

Non-Perturbative QFT Methods and Their Applications

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An exact renormalization group equation describes the dependence of the free energy on an infrared cutoff for the quantum or thermal fluctuations. It interpolates between the microphysical laws and the complex macroscopic phenomena. We present a simple unified description of critical phenomena for O(N )-symmetric scalar models in two, three or four dimensions, including essential scaling for the Kosterlitz-Thouless transition.

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Fermi level dependence of hydrogen diffusivity in GaN

Abstract: Articles you may be interested inDiffusion of Mg dopant in metal-organic vapor-phase epitaxy grown GaN and AlxGa1−xN

Cited by 71 publications

References 18 publications

Non-perturbative renormalization flow in quantum field theory and statistical physics

Non-perturbative renormalization flow in quantum field theory and statistical physics

Notes on parafermionic QFTs with boundary interaction

Effective Average Action in Statistical Physics and Quantum Field Theory

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