Condensed matter physics is a study of complex phenomena arising from interactions of many particles. It includes studies of solids, liquids, gases, plasmas, bio-molecules, etc., where even fundamentally very simple constituent particles (electrons, grain of sand, etc.) can lead to complex behaviors in systems consisting of ~1023 particles.

Condensed matter physics is often motivated by the search for new materials with unexpected properties. It is an extremely active, dynamic field of research and is the largest subfield of modern physics, with over a third of the members of the American Physical Society being condensed matter physicists of one kind or another. In the last 20 years, more than 25 Nobel Prizes were awarded to condensed matter physicists.

In many systems, the constituent particles are well-described by classical mechanics, and the quantum-mechanical effects in their interactions can be neglected. Such systems are said to be subject of “soft” condensed matter physics. The word “soft” in this context does not have anything to do with the softness of the resulting material, but is just a proxy for the classical nature of the particles.

Example research topics in soft condensed matter physics being pursued in our department include:

  • friction, fracture, adhesion and lubrication
  • liquid crystals
  • biological physics
  • complex fluids

The theoretical and experimental tools of soft condensed matter physics are:

  •  statistical physics
  •  numerical simulations
  •  study of transport phenomena
  •  thermodynamical measurements
  • optical / neutron / X-ray scattering

Quantum mechanics is required in order to understand the behavior of many systems, even when the systems themselves are macroscopic in size. For example, systems whose behavior relies on interactions between individual electrons, cannot be understood on the basis of classical mechanics alone. Such systems are the subject of “hard” condensed matter physics, where again the work “hard” does not imply that the resulting materials are hard in the everyday sense of the word.

Researchers in our department conduct investigations in many areas of hard condensed matter physics:

  •  high temperature superconductivity
  •  strong correlations
  •  topological phases of quantum matter
  •  quantum magnetism
  •  Bose-Einstein condensates
  •  nanostructures
  •  quantum computing
  •  synthesis of new quantum materials

The theoretical tools of hard condensed matter physics are:

  •  quantum statistical and many-body physics
  •  quantum numerical simulations
  •  quantum field theory and non-perturbative approaches

Experimental tools are similar to those employed in soft condensed matter physics.

Prof. N. Peter Armitage and Postdoctoral Fellow LiDong Pan tuning the laser in the THz spectroscopy lab.