dc.contributor.author	Park, Hyunhang	en
dc.contributor.committeechair	Pleimling, Michel J.	en
dc.contributor.committeemember	Heremans, Jean J.	en
dc.contributor.committeemember	Tauber, Uwe C.	en
dc.contributor.committeemember	Mather, William	en
dc.contributor.department	Physics	en
dc.date.accessioned	2013-04-13T08:00:21Z	en
dc.date.available	2013-04-13T08:00:21Z	en
dc.date.issued	2013-03-22	en
dc.description.abstract	Among the many non-equilibrium processes encountered in nature we deal with two different but related aspects. One is the non-equilibrium relaxation process that is at the origin of \'aging phenomena••, and the other one is a non-equilibrium phase transition, called ••dynamic phase transition••. One of the main purposes of our research is to explore more realistic situations than studied previously. Indeed, in the study of aging phenomena certain kinds of disorder effects are considered, and we introduce the ••surface•• as a spatial boundary to the system undergoing the dynamic phase transition. In order to observe these processes as clearly as possible, we study in both cases simple spin systems. Using Monte Carlo simulations we first investigate aging in three-dimensional Ising spin glasses as well as in two-dimensional Ising models with disorder quenched to low temperatures. The time-dependent dynamical correlation length L(t) is determined numerically and the scaling behavior of various two-time quantities as a function of L(t)/L(s) is discussed where t and s are two different times. For disordered Ising models deviations of L(t) from algebraic growth law show up. The generalized scaling forms as a function of L(t)/L(s) reveal a generic simple aging scenario for Ising spin glasses as well as for disordered Ising ferromagnets. We also study the local critical phenomena at a dynamic phase transition by means of numerical simulations of kinetic Ising models with surfaces subjected to a periodic oscillating field. We examine layer-dependent quantities, such as the period-averaged magnetization per layer Q(z) and the layer susceptibility ¥ö(z), and determine local critical exponents through finite size scaling. Both for two and three dimensions, we find that the values of the surface exponents differ from those of the equilibrium critical surface. It is revealed that the surface phase diagram of the non-equilibrium system is not identical to that of the equilibrium system in three dimensions.	en
dc.description.degree	Ph. D.	en
dc.format.medium	ETD	en
dc.identifier.other	vt_gsexam:425	en
dc.identifier.uri	http://hdl.handle.net/10919/19323	en
dc.publisher	Virginia Tech	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	Aging Phenomena	en
dc.subject	Disordered Ferromagnets	en
dc.subject	Dynamical Scaling	en
dc.subject	Dynamic Phase Transition	en
dc.subject	Surface Critical Phenomena	en
dc.subject	Surface Phase Diagram	en
dc.title	Spin Systems far from Equilibrium: Aging and Dynamic Phase Transition	en
dc.type	Dissertation	en
thesis.degree.discipline	Physics	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	doctoral	en
thesis.degree.name	Ph. D.	en

Spin Systems far from Equilibrium: Aging and Dynamic Phase Transition

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