University of Minnesota
School of Physics & Astronomy


Out of Equilibrium

Jorge Vinals
Jorge Vinals
Richard Anderson

While most everyday observations of nature reflect its ever changing state, the subset of processes that physicists understand best are those in which the system studied is in equilibrium. Jorge Vinals is a theoretical physicist whose research focuses on systems that are out of equilibrium.

Two common features of non equilibrium systems are the formation of patterns and the appearance of peculiar states of "chaos." In the former case, when a system is away from equilibrium, it often evolves by developing complex spatial patterns or shapes.

A snowflake is a familiar example in Minnesota, a pattern which appears spontaneously when water crystallizes from the vapor. Other examples include rotating vortices in the atmosphere, i.e. tornadoes; air movement along the wings of an airplane that keep it in flight, or water draining from a sink. In all cases, the scale and properties of these characteristic patterns control the behavior of the system (weather, aircraft lift, and whether you need a plunger), and hence their formation and evolution needs to be understood.

Other examples of continuously evolving systems outside of equilibrium include the distribution of galaxies in the Universe, and the neuronal network in your brain. In many cases, the ultimate destination in the evolution is a state of equilibrium. In others, however, the system refuses to reach a state in which its observable properties become independent of time: persistent dynamics and chaos may ensue. Despite how common this latter situation is in nature, little is understood of larger systems (many degrees of freedom in the Physics parlance).

One particular application of these concepts that Vinals is studying concerns the formation of modulated phases in block polymers. The patterns that spontaneously form in these materials are finding many novel applications in nanotechnology. Frequency tunable waveguides and mirrors, as templates to produce smaller features in semiconductors for ever smaller computer chips, or as templates to produce ultra high density disk drives are examples of new applications. Controlling their evolution while out of equilibrium, and nudge them while en route to a useful final structure, is key in realizing their potential in nanotechnology.