Dynamics of the Order Parameter Field

2021 ◽  
pp. 231-239
2003 ◽  
Vol 18 (36) ◽  
pp. 2587-2597 ◽  
Author(s):  
PENG-MING ZHANG ◽  
YI-SHI DUAN ◽  
LI-MING CAO

We present a whole frame for the cosmic strings, inflation and dark energy with the complex scalar field which can be regarded as the order parameter of our universe. One can find that the comic strings emerge in the zeros of the complex scalar field in the early universe. And with the evolution of complex scalar field, inflation and dark energy can be understood in this frame.


2010 ◽  
Vol 667 ◽  
pp. 158-187 ◽  
Author(s):  
MICHAEL WILKINSON ◽  
VLAD BEZUGLYY ◽  
BERNHARD MEHLIG

We consider the ordering of particles in a rheoscopic fluid (a suspension of microscopic rod-like particles) in a steady two-dimensional flow, and discuss its consequences for the reflection of light. The ordering is described by an order parameter which is a non-oriented vector, obtained by averaging solutions of a nonlinear equation containing the strain rate of the fluid flow. Exact solutions of this equation are obtained from solutions of a linear equation which are analogous to Bloch bands for a one-dimensional Schrödinger equation with a periodic potential. On some contours of the stream function, the order parameter approaches a limit, and on others it depends increasingly sensitively upon position. However, in the long-time limit a local average of the order parameter is a smooth function of position in both cases. We analyse the topology of the order parameter and the structure of the generic zeros of the order parameter field.


2007 ◽  
Vol 22 (07) ◽  
pp. 1335-1351 ◽  
Author(s):  
Y. S. DUAN ◽  
L. ZHAO

By making use of the gauge potential decomposition theory and ϕ-mapping theory, the topological structure and the topological quantization of dislocations and disclinations are studied in the framework of Riemann–Cartan space–time manifold. The evolution of dislocation strings and disclination points is also studied from the topological properties of the order parameter field. The dislocations and disclinations are found generating or annihilating at the limit points and encountering, splitting, or merging at the bifurcation points of the order parameter field.


1996 ◽  
Vol 345 (1-2) ◽  
pp. 138-154 ◽  
Author(s):  
Yu.N. Devyatko ◽  
S.V. Rogozhkin ◽  
B.A. Fedotov

2004 ◽  
Vol 19 (10) ◽  
pp. 1511-1524
Author(s):  
RAJARSHI RAY ◽  
SOMA SANYAL ◽  
AJIT M. SRIVASTAVA

We investigate the dynamics of a first order transition when the order parameter field undergoes resonant oscillations, driven by a periodically varying parameter of the free energy. This parameter could be a background oscillating field as in models of pre-heating after inflation. In the context of condensed matter systems, it could be temperature T, or pressure, external electric/magnetic field etc. We show that with suitable driving frequency and amplitude, the system remains in a type of mixed phase, without ever completing transition to the stable phase, even when the oscillating parameter of the free energy remains below the corresponding critical value (for example, with oscillating temperature, T always remains below the critical temperature Tc). This phenomenon may have important implications. In cosmology, it will imply prolonged mixed phase in a first order transition due to coupling with background oscillating fields. In condensed matter systems, it will imply that using oscillating temperature (or, more appropriately, pressure waves) one may be able to sustain liquids in a mixed phase indefinitely at low temperatures, without making transition to the frozen phase.


2010 ◽  
Vol 20 (04) ◽  
pp. 519-541 ◽  
Author(s):  
PIERLUIGI COLLI ◽  
GIANNI GILARDI ◽  
PAOLO PODIO-GUIDUGLI ◽  
JÜRGEN SPREKELS

We study a model of phase segregation of the Allen–Cahn type, consisting in a system of two differential equations, one partial and the other ordinary, respectively interpreted as balances of microforces and microenergy; the two unknowns are the order parameter entering the standard A–C equation and the chemical potential. We introduce a notion of maximal solution to the o.d.e., parametrized on the order-parameter field; and, by substitution in the p.d.e. of the so-obtained chemical potential field, we give the latter equation the form of an Allen–Cahn equation for the order parameter, with a memory term. Finally, we prove the existence and uniqueness of global-in-time smooth solutions to this modified A–C equation, and we give a description of the relative ω-limit set.


Sign in / Sign up

Export Citation Format

Share Document