Renormalization Group for the Heisenberg Magnet in a Random Magnetic Field: The Zero-Temperature Fixed Point

1994 ◽  
Vol 26 (5) ◽  
pp. 377-382
Author(s):  
Y. S Parmar
Keyword(s):  
Magnetic Field ◽  
Fixed Point ◽  
Renormalization Group ◽  
Heisenberg Magnet ◽  
Zero Temperature ◽  
Random Magnetic Field

scholarly journals Loop expansion around the Bethe solution for the random magnetic field Ising ferromagnets at zero temperature

2020 ◽  
Vol 117 (5) ◽  
pp. 2268-2274
Author(s):  
Maria Chiara Angelini ◽  
Carlo Lucibello ◽  
Giorgio Parisi ◽  
Federico Ricci-Tersenghi ◽  
Tommaso Rizzo
Keyword(s):  
Magnetic Field ◽  
Fixed Point ◽  
Disordered Systems ◽  
Effective Theory ◽  
Zero Temperature ◽  
Random Field Ising Model ◽  
Loop Expansion ◽  
Random Magnetic Field ◽  
Ising Ferromagnets ◽  
The One

We apply to the random-field Ising model at zero temperature (T=0) the perturbative loop expansion around the Bethe solution. A comparison with the standard ϵ expansion is made, highlighting the key differences that make the expansion around the Bethe solution much more appropriate to correctly describe strongly disordered systems, especially those controlled by a T=0 renormalization group (RG) fixed point. The latter loop expansion produces an effective theory with cubic vertices. We compute the one-loop corrections due to cubic vertices, finding additional terms that are absent in the ϵ expansion. However, these additional terms are subdominant with respect to the standard, supersymmetric ones; therefore, dimensional reduction is still valid at this order of the loop expansion.

scholarly journals THE RENORMAUZATION GROUP FOR FLAG MANIFOLDS

1993 ◽  
Vol 08 (20) ◽  
pp. 3509-3528 ◽  
Author(s):  
S. RANDJBAR-DAEMI ◽  
J. STRATHDEE
Keyword(s):  
Fixed Point ◽  
Renormalization Group ◽  
Continuum Limit ◽  
Flag Manifolds ◽  
Zero Temperature ◽  
Nonrelativistic Quantum ◽  
Target Manifold ◽  
Renormalization Group Equations ◽  
Heisenberg Antiferromagnets

The renormalization group equations for a class of nonrelativistic quantum σ-models targeted on flag manifolds are given. These models emerge in a continuum limit of generalized Heisenberg antiferromagnets. The case of the [Formula: see text] manifold is studied in greater detail. We show that at zero temperature there is a fixed point of the RG transformations in (2 + ε) dimensions where the theory becomes relativistic. We study the linearized RG transformations in the vicinity of this fixed point and show that half of the couplings are irrelevant. We also show that at this fixed point there is an enlargement of the global isometries of the target manifold. We construct a discrete non-Abelian enlargement of this kind.

scholarly journals THE CASE OF ASYMPTOTIC SUPERSYMMETRY

2013 ◽  
Vol 28 (14) ◽  
pp. 1350053 ◽  
Author(s):  
BRUCE L. SÁNCHEZ-VEGA ◽  
ILYA L. SHAPIRO
Keyword(s):  
Fixed Point ◽  
Renormalization Group ◽  
Gauge Coupling ◽  
High Energy ◽  
Systematic Investigation ◽  
Coupling Constants ◽  
Scalar Coupling ◽  
Asymptotic State ◽  
Stable Fixed Point ◽  
Scalar Couplings

We start systematic investigation for the possibility to have supersymmetry (SUSY) as an asymptotic state of the gauge theory in the high energy (UV) limit, due to the renormalization group running of coupling constants of the theory. The answer on whether this situation takes place or not, can be resolved by dealing with the running of the ratios between Yukawa and scalar couplings to the gauge coupling. The behavior of these ratios does not depend too much on whether gauge coupling is asymptotically free (AF) or not. It can be shown that the UV stable fixed point for the Yukawa coupling is not supersymmetric. Taking this into account, one can break down SUSY only in the scalar coupling sector. We consider two simplest examples of such breaking, namely N = 1 supersymmetric QED and QCD. In one of the cases one can construct an example of SUSY being restored in the UV regime.

Superconductors with spin–orbit interactions

2016 ◽  
Vol 30 (25) ◽  
pp. 1650183 ◽  
Author(s):  
Yu. N. Ovchinnikov
Keyword(s):  
Magnetic Field ◽  
Superconducting Films ◽  
Critical Magnetic Field ◽  
Spin Orbit ◽  
Zero Temperature ◽  
Interband Pairing ◽  
Two Parameters ◽  
Spin Orbit Interactions ◽  
Parameter Values ◽  
Thin Superconducting Films

The effect of spin-orbit (SO) interaction on the formation of the critical states in thin superconducting films in magnetic field oriented along the film is investigated. Hereby, the case of interband pairing is considered. It was found that eight branches exist in the plane of two parameters [Formula: see text] determined by the value of magnetic field and SO interaction. Six modes leads to inhomogeneous states with different values of the impulse [Formula: see text]. Each state is doubly degenerate over direction of impulse [Formula: see text]. The parameter values at critical point are found for all eight branches in explicit form for zero temperature. The optimal two branches are estimated, corresponding to largest critical magnetic field value for given SO interaction.

Two-dimensional electron in a random magnetic field

1994 ◽  
Vol 49 (5) ◽  
pp. 3340-3346 ◽  
Author(s):  
Armelle Barelli ◽  
Robert Fleckinger ◽  
Timothy Ziman
Keyword(s):  
Magnetic Field ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Random Magnetic Field
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