SOLITONS AND BUBBLES IN MODELS WITH CHERN-SIMONS TERM

1992 ◽  
Vol 07 (34) ◽  
pp. 3245-3254
Author(s):  
L. MASPERI
Keyword(s):  
Complex Scalar ◽  
Relativistic Limit ◽  
First Order ◽  
String Type ◽  
First Order Phase Transition ◽  
Symmetry Phase ◽  
Complex Scalar Field ◽  
First Order Phase ◽  
Chern Simons

It is shown that a gauge theory for complex scalar field with up to sextic self-interactions and a Chern-Simons term in 2+1 dimensions has solitons which may become bubbles of the stable broken-symmetry phase in a medium of the symmetric one producing the first order phase transition. In the non-relativistic limit scale invariance prevents the determination of an optimal bubble size. Possible extensions to 3 + 1 dimensions of bubbles of string type are indicated.

Magnetic Anisotropy Constants of Epitaxial (110) Fe/GaAs Films from 77k To 293k Studied by Magneto-Resistance

1989 ◽  
Vol 151 ◽  
Author(s):  
Daniel K. Lottis ◽  
G. A. Prinz ◽  
E. Dan Dahlberg
Keyword(s):  
Phase Transition ◽  
Uniaxial Anisotropy ◽  
Epitaxial Films ◽  
Effective Anisotropy ◽  
First Order ◽  
First Order Phase Transition ◽  
Gaas Films ◽  
First Order Phase ◽  
Magneto Resistance

ABSTRACTA first-order phase transition in the magnetization of Fe films, driven by an applied magnetic field, was first reported by Hathaway and Prinz [1]. Further studies were performed on this phase transition using anisotropic magnetoresistance measurements by Riggs and Dahlberg [2]. Here we report the extension of these studies to include temperatures between 77K and 293K. Emphasis is on a determination of the fourth-order and uniaxial anisotropy constants (K1 and Ku). It is shown that the temperature dependence of the anisotropy energies in these films varies with thickness, which may be useful in sorting out the origin and magnitude of different contributions to the total effective anisotropy. The present study suggests that similar studies of (110) iron on other substrates might contribute to achieving a better understanding of in-plane anisotropies in epitaxial films.

Statistical Mechanical Determination of nanocluster size distributions in the phase coexistence region of a first order phase transition from the isotherms of DMPC monolayers at the air-water interface

2021 ◽  
Author(s):  
Eiji Hatta ◽  
Ko Nihei
Keyword(s):  
Surface Pressure ◽  
Size Distributions ◽  
Coexistence Region ◽  
First Order ◽  
First Order Phase Transition ◽  
Air Water Interface ◽  
Pressure Area ◽  
Statistical Mechanical ◽  
First Order Phase

A statistical mechanical deconvolution procedure for the experimentally measured surface pressure –area isotherms has been presented to obtain the surface pressure dependence of the liquid expanded (LE) and liquid condensed...

WEIGHT RATIO FIXING AT FIRST ORDER PHASE TRANSITIONS

1992 ◽  
Vol 03 (05) ◽  
pp. 1109-1117
Author(s):  
THOMAS LIPPERT ◽  
KLAUS SCHILLING ◽  
PEER UEBERHOLZ ◽  
GYAN BHANOT
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Weight Ratio ◽  
Phenomenological Method ◽  
Reliable Determination ◽  
First Order ◽  
First Order Phase Transition ◽  
Two Phases ◽  
First Order Phase

The presence of strong metastabilities in computer simulations of models showing a first order phase transition hinders a reliable determination of the weight ratio between the two phases. We discuss a new phenomenological method which allows an accurate fixing of the weight ratio using the standard multihistogram procedure.

SOME THOUGHTS ON THE COSMOLOGICAL QCD PHASE TRANSITION

2008 ◽  
Vol 23 (30) ◽  
pp. 4757-4777
Author(s):  
W-Y. P. HWANG
Keyword(s):  
Phase Transition ◽  
Scalar Field ◽  
Order Phase Transition ◽  
Domain Walls ◽  
Wall Structure ◽  
Complex Scalar ◽  
Qcd Phase Transition ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase

The cosmological QCD phase transitions may have taken place between 10-5 s and 10-4 s in the early universe offers us one of the most intriguing and fascinating questions in cosmology. In bag models, the phase transition is described by the first-order phase transition and the role played by the latent "heat" or energy released in the transition is highly nontrivial and is being classified as the first-order phase transition. In this presentation, we assume, first of all, that the cosmological QCD phase transition, which happened at a time between 10-5 s and 10-4 s or at the temperature of about 150 MeV and accounts for confinement of quarks and gluons to within hadrons, would be of first-order. Of course, we may assume that the cosmological QCD phase transition may not be of the first-order. To get the essence out of the first-order scenario, it is sufficient to approximate the true QCD vacuum as one of possibly degenerate vacua and when necessary we try to model it effectively via a complex scalar field with spontaneous symmetry breaking. On the other hand, we may use a real scalar field in describing the non-first-order QCD phase transition. In the first-order QCD phase transition, we could examine how and when "pasted" or "patched" domain walls are formed, how long such walls evolve in the long run, and we believe that the significant portion of dark matter could be accounted for in terms of such domain-wall structure and its remnants. Of course, the cosmological QCD phase transition happened in the way such that the false vacua associated with baryons and many other color-singlet objects did not disappear (that is, using the bag-model language, there are bags of radius 1.0 fermi for the baryons) — but the amount of the energy remained in the false vacua is negligible by comparison. The latent energy released due to the conversion of the false vacua to the true vacua, in the form of "pasted" or "patched" domain walls in the short run and their numerous evolved objects, should make the concept of the "radiation-dominated" epoch, or of the "matter-dominated" epoch to be reexamined.

Determination of the low-temperature structure of hexamethylbenzene

2005 ◽  
Vol 61 (2) ◽  
pp. 200-206 ◽  
Author(s):  
John A. Stride
Keyword(s):  
Low Temperature ◽  
Temperature Phase ◽  
Temperature Structure ◽  
Thermally Induced ◽  
First Order ◽  
Neutron Powder Diffraction Data ◽  
First Order Phase Transition ◽  
First Order Phase

The low-temperature structure of hexamethylbenzene has been determined from neutron powder diffraction data and found to differ from the room-temperature phase predominantly by a translation of molecular planes to a form a cubic close-packed type structure. By performing measurements as a function of temperature, the role of thermally induced agitation of the molecular units in the first-order phase transition is clearly demonstrated.

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.

Direct Access to the Order Parameter: Parameterized Symmetry Modes and Rigid Body Movements as a Function of Temperature

2010 ◽  
Vol 651 ◽  
pp. 79-95 ◽  
Author(s):  
Melanie Müller ◽  
Robert E. Dinnebier ◽  
Naveed Z. Ali ◽  
Branton J. Campbell ◽  
Martin Jansen
Keyword(s):  
Lattice Strain ◽  
Landau Theory ◽  
Direct Access ◽  
High Symmetry ◽  
First Order ◽  
Synchrotron Powder Diffraction ◽  
First Order Phase Transition ◽  
Alternative Approaches ◽  
First Order Phase

The first order phase transition of CsFeO2 was investigated using synchrotron powder diffraction data as a function of temperature. Two alternative approaches were used to describe the deviation of the framework crystal structure relative to the high-symmetry parent structure: symmetry (a.k.a. distortion) modes and polyhedral-tilt parameters. In both cases, the relevant parameters were refined as a function of temperature using the method of parametric Rietveld refinement. We demonstrate a semi-automated and generally applicable method for the determination of spontaneous lattice strain variations, order parameters and power-law exponents as derived from Landau theory.

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