slideshow 3

Cohomology in algebra, geometry, physicsand statistics

Lorentzian Symmetry Predicts Universality Beyond Power Laws

Speaker’s name: 
Stephen Watson
Speaker’s affiliation: 
University of Glasgow

 

Place: 
ZOOM meeting
Date: 
Wednesday, 24. June 2020 - 11:30 to 12:30
Abstract: 
The statistical physics governing phase-ordering dynamics following a symmetry breaking first-order phase transition is an area of active research. The Coarsening/Ageing of the ensemble of phase domains, wherein  irreversible annihilation or joining of domains yields a growing characteristic domain length, is a omniprescent feature whose universal characteristics one would wish to understand. Driven kinetic Ising models and growing nano-faceted crystals are theoretically important examples of such Coarsening (Ageing) Dynamical Systems (CDS), since they additionally break thermodynamic fluctuation-dissipation relations.
Power-laws for the growth in time of the characteristic size of domains (e.g., lengths) of  CDS, and a concomitant {\em scale-invariance} of the associated length distributions,  has so frequently been empirically observed that their presence has acquired the status of a principle; the so-called Dynamic-Scaling Hypothesis. 
But the dynamical symmetries of a given CDS- its Coarsening Group $G$ - may include more than the global spatio-temporal scalings underlying the {\em Dynamic Scaling Hypothesis}. 
In this talk, I will present a recently developed theoretical framework (Ref.[1]) that shows how the symmetry group G of a Coarsening (ageing) Dynamical System (CDS) necessarily yields G-equivariance (covariance) of the CDS's  universal statistical observables. We exhibit this theory for a variety of model systems, of both thermodynamic and driven type, with symmetries that may also be {/em emergent} (Ref. [2,3]) and/or {\em hidden}. We will close with a magical theoretical coarsening law which reflects Lorentzian and parabolic symmetries!
 
References
 
Lorentzian symmetry predicts universality beyond scaling laws,
SJ Watson, EPL 118 (5), 56001, (Aug.2, 2017), Editor's Choice
 Emergent parabolic scaling of nano-faceting crystal growth,
Stephen J. Watson,  Proc. R. Soc. A 471: 20140560 (2015)
[3]  http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.96.176103
Scaling Theory and Morphometrics for a Coarsening Multiscale Surface, via a Principle of Maximal Dissipation,
Stephen J. Watson and Scott A. Norris, Phys. Rev. Lett. 96, 176103 (2006)

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