scholarly journals Solving puzzles in deformed JT gravity: phase transitions and non-perturbative effects

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Clifford V. Johnson ◽  
Felipe Rosso
Keyword(s):  
Phase Structure ◽  
Scalar Potential ◽  
String Equation ◽  
Two Dimensional ◽  
Leading Order ◽  
Classical Analysis ◽  
First Order ◽  
First Order Phase Transition ◽  
Definition Of ◽  
First Order Phase

Abstract Recent work has shown that certain deformations of the scalar potential in Jackiw-Teitelboim gravity can be written as double-scaled matrix models. However, some of the deformations exhibit an apparent breakdown of unitarity in the form of a negative spectral density at disc order. We show here that the source of the problem is the presence of a multi-valued solution of the leading order matrix model string equation. While for a class of deformations we fix the problem by identifying a first order phase transition, for others we show that the theory is both perturbatively and non-perturbatively inconsistent. Aspects of the phase structure of the deformations are mapped out, using methods known to supply a non-perturbative definition of undeformed JT gravity. Some features are in qualitative agreement with a semi-classical analysis of the phase structure of two-dimensional black holes in these deformed theories.

scholarly journals PHASE STRUCTURE OF A FOUR- AND EIGHT-FERMION INTERACTION MODEL AT FINITE TEMPERATURE AND CHEMICAL POTENTIAL IN ARBITRARY DIMENSIONS

2010 ◽  
Vol 25 (25) ◽  
pp. 4757-4774 ◽  
Author(s):  
MASAKO HAYASHI ◽  
TOMOHIRO INAGAKI ◽  
WATARU SAKAMOTO
Keyword(s):  
Finite Temperature ◽  
Phase Structure ◽  
Chemical Potential ◽  
Interaction Model ◽  
Leading Order ◽  
First Order ◽  
First Order Phase Transition ◽  
Arbitrary Space ◽  
Arbitrary Dimensions ◽  
First Order Phase

The phase structure of a four- and eight-fermion interaction model is investigated at finite temperature and chemical potential in arbitrary space–time dimensions, 2 ≤ D < 4. The effective potential and the gap equation are calculated in the leading order of the 1/N expansion. If the first order phase transition takes place, the phase boundary dividing the symmetric and the broken phase is modified by the eight-fermion interaction.

scholarly journals NAMBU-JONA-LASINIO MODEL IN CURVED SPACE-TIME

1993 ◽  
Vol 08 (22) ◽  
pp. 2117-2123 ◽  
Author(s):  
T. INAGAKI ◽  
T. MUTA ◽  
S.D. ODINTSOV
Keyword(s):  
Proper Time ◽  
Space Time ◽  
Leading Order ◽  
Coupling Constant ◽  
Normal Coordinate ◽  
Dynamical Mass ◽  
Curved Space ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase

The phase structure of Nambu-Jona-Lasinio model with N-component fermions in curved space-time is studied in the leading order of the 1/N expansion. The effective potential for composite operator [Formula: see text] is calculated by using the normal coordinate expansion in the Schwinger proper-time method. The existence of the first order phase transition caused by the change of the space-time curvature is confirmed and the dynamical mass of the fermion is calculated as a simultaneous function of the curvature and the four-fermion coupling constant. The phase diagram in the curvature and the coupling constant is obtained.

scholarly journals Topological metals and finite-momentum superconductors

2021 ◽  
Vol 118 (3) ◽  
pp. e2019063118
Author(s):  
Noah F. Q. Yuan ◽  
Liang Fu
Keyword(s):  
Cooper Pair ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Two Dimensional ◽  
Discontinuous Change ◽  
Zeeman Field ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase ◽  
2D Superconductors

We show that the Zeeman field can induce a topological transition in two-dimensional spin–orbit-coupled metals and, concomitantly, a first-order phase transition in the superconducting state involving a discontinuous change of Cooper pair momentum. Depending on the spin–orbit coupling strength, we find different phase diagrams of two-dimensional (2D) superconductors under in-plane magnetic field.

scholarly journals A first order dark SU(2) D phase transition with vector dark matter in the light of NANOGrav 12.5 yr data

2021 ◽  
Vol 2021 (12) ◽  
pp. 039
Author(s):  
Debasish Borah ◽  
Arnab Dasgupta ◽  
Sin Kyu Kang
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Scalar Potential ◽  
Dark Sector ◽  
Complex Scalar ◽  
First Order ◽  
First Order Phase Transition ◽  
Vector Bosons ◽  
Relic Abundance ◽  
First Order Phase

Abstract We study a dark SU(2) D gauge extension of the standard model (SM) with the possibility of a strong first order phase transition (FOPT) taking place below the electroweak scale in the light of NANOGrav 12.5 yr data. As pointed out recently by the NANOGrav collaboration, gravitational waves (GW) from such a FOPT with appropriate strength and nucleation temperature can explain their 12.5 yr data. We impose a classical conformal invariance on the scalar potential of SU(2) D sector involving only a complex scalar doublet with negligible couplings with the SM Higgs. While a FOPT at sub-GeV temperatures can give rise to stochastic GW around nano-Hz frequencies being in agreement with NANOGrav findings, the SU(2) D vector bosons which acquire masses as a result of the FOPT in dark sector, can also serve as dark matter (DM) in the universe. The relic abundance of such vector DM can be generated in a non-thermal manner from the SM bath via scalar portal mixing. We also discuss future sensitivity of gravitational wave experiments to the model parameter space.

Notizen: Monte-Carlo Simulation of a Two-dimensional Dipolar Lattice

1977 ◽  
Vol 32 (11) ◽  
pp. 1320-1322 ◽  
Author(s):  
S. Romano
Keyword(s):  
Monte Carlo ◽  
Mean Field Theory ◽  
Mean Field ◽  
Square Lattice ◽  
Electrostatic Energy ◽  
Two Dimensional ◽  
First Order ◽  
First Order Phase Transition ◽  
The Mean ◽  
First Order Phase

Abstract Monte-Carlo calculations were carried out on a system consisting of 256 point-dipoles, whose centres are fixed in a two-dimensional square lattice with the usual boundary con­dition; the Epstein-Ewald-Kornfeld algorithm was used in evaluating the electrostatic energy. No evidence of a first-order phase transition was found, and the results suggest there might be a second-order one. Additional calculations were carrierd out using the mean-field theory, which was found to overestimate the transition temperature by about a factor two.

scholarly journals CHIRAL SYMMETRY BREAKING IN THE d = 3 NAMBU-JONA-LASINIO MODEL IN CURVED SPACE-TIME

1994 ◽  
Vol 09 (10) ◽  
pp. 913-918 ◽  
Author(s):  
E. ELIZALDE ◽  
S. D. ODINTSOV ◽  
YU. I. SHIL'NOV
Keyword(s):  
Phase Transition ◽  
Order Phase Transition ◽  
Chiral Symmetry Breaking ◽  
Space Time ◽  
Leading Order ◽  
Curved Space ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase ◽  
Curvature Approximation

The phase structure of the d = 3 Nambu-Jona-Lasinio model in curved space-time is considered to leading order in the 1/N-expansion and in the linear curvature approximation. The possibility of a curvature-induced first order phase transition is investigated numerically. The dynamically generated fermionic mass is calculated for some values of the curvature.

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