Recent News
Education
Ph.D., University of Illinois at Urbana-Champaign (1998)
- Research
- Courses Taught
- Professional Associations
- Invited Talks
- Publications
- Graduate Students
- Personal Profile
Research
Supercooled liquids, glasses and granular materials:
Many condensed matter systems exhibit transitions in which they freeze into a disordered solid state. Glasses, plastics, and granular materials (such as sand or powders) are some examples of this kind of disordered solid. Despite their practical importance, many aspects of these transitions are still poorly understood. One such aspect is the presence of spatially extended fluctuations, called "dynamical heterogeneities," which have been qualitatively interpreted in terms of the presence of a local relaxation time that varies over space and time, thus defining fast and slow regions in the material.
Our group performs theoretical calculations and numerical simulations to study fluctuations in glasses and granular materials. We are interested both in equilibrium behavior, where the macroscopic state of the system stays constant over time, and on nonequilibrium (aging) behavior, where the system is evolving towards equilibrium. The analytical approaches that we use include the path-integral formulation of the Martin-Siggia-Rose formalism, sometimes combined with Renormalization Group techniques, to study the dynamics in systems under the presence of disorder and thermal fluctuations. The numerical techniques include classical Molecular Dynamics and dynamical Monte Carlo simulations. We are also interested in re-analyzing in novel ways the existing experimental data from our collaborators.
Courses Taught
- Undergraduate:Quantum Mechanics, Classical Mechanics, Honors Tutorials Physics (calculus based), General Physics (calculus based), Introduction to Physics (algebra based)
- Graduate:Statistical Mechanics, Condensed Matter Physics, Mathematical Methods in Physics
Professional Associations
Invited Talks
- "Fluctuations in the relaxation of a 2D granular fluid", colloquium at OU Department of Chemical Engineering, November 2015 (printable version)
- "Fluctuations in the relaxation of glasses", invited talk, Konstanz, May 2012 (printable version)
- " Does Dynamical Heterogeneity Originate in Fluctuations of the Time Variable? ", seminar at the workshop "The Physics of Glasses", KITP, Santa Barbara, July 2010 (video)
Publications
Preprints in arXiv (always up to date)
Graduate Students
Current
- Sai Teja Pusuluri
- Rajib Pandit
Former
- Karina Avila-Coronado (PhD 2013)
- Gcina Mavimbela (PhD 2012)
- Steven Rogers (Undergraduate Honors Tutorial College thesis 2010)
- Azita Parsaeian (PhD 2009)
- Allen Dahili (MSc 2005)
Personal Profile
Horacio Castillo is a condensed matter theorist. His research focuses on disordered systems.
Castillo's contributions further our understanding of the elastic properties of rubber, the behavior of electrons in certain disordered solids, and the motion of defects in certain crystals.
Lately, he has been interested in understanding ``Physical Aging.'' This phenomenon is characteristic of glasses and other materials that slowly change their properties with time, even when the temperature, pressure, and other external conditions are kept constant. Most of his recent work on aging has involved numerical simulations using Monte Carlo and Molecular Dynamics methods.
When he is not doing research or teaching, Castillo enjoys hiking, playing with his dog Bear, and swimming.