Overview
The Department of Physics of Complex Systems pursues two main directions, Atomic, Molecular and Optical (AMO) physics and the physics of Soft and Biological Matter. Contemporary topics in AMO physics range from atto-second pulses and intense lasers, through precision spectroscopy of ultracold atoms, molecules or ions, to quantum information and quantum optics. Soft and biological physics are characterized by wide ranging complexity that can often be simplified by considering fundamental physical concepts and principles. The Department consists of slightly under 20 groups, of which about two thirds are experimentalists and one third are theoreticians.
Atomic, Molecular and Optical Physics
The AMO groups in the Department of Physics of Complex Systems study a wide variety of topics in nonlinear and quantum optics, atomic and molecular physics. Of interest are the properties of atoms and ions at ultra-cold temperatures where full control of individual atoms and photons is possible and quantum phenomena are manifested. These unique properties can be applied for quantum sensing, simulations and computing and study of new physics. Both theoretical and experimental aspects of Quantum Computation comprise an important and very significant goal of the research.
A particularly rich field of study is that of the interaction of ultrashort optical pulses with atoms, molecules, electrons and solids, which enables the measurement of ultrafast dynamics, allows the acceleration of electrons and protons, and generates new radiation sources for bio-medical applications. In addition, investigations of the geometrical quantum nature of light are conducted, along with its use for simulating general relativity in the lab.
Soft Matter and Biological Physics
The theoretical issues in soft matter cover non-equilibrium processes and aspects of emergent properties, of frustration and of material structure, all of which can be approached using the tools of statistical mechanics coupled with a deep mathematical description of organization in matter. Structures in liquid and organic crystals, as well as in viscoelastic material yield insight on the underlying physical processes and mechanisms. In biological systems, mechanisms that determine the size of cells can be obtained using physics modeling and theoretical concepts. In considering the statistical physics of turbulence, special emphasis is made on broken and emerging symmetries, with important implications for conformal invariance in inverse turbulent cascades and recently for the kinetic and hydrodynamic theory of emerging viscous electronics.
The experimental labs treat such diverse systems as ants, single molecules, neuronal cultures, one dimensional organisms, and even human groups. A unifying theme lies in relating the properties of the constituent parts to those of the emerging whole. Biological computation is treated in social contexts such as ant colonies and in devices comprised of living neurons. Emergent properties such as synchronization of activity, decision making and resource sharing are among the novel phenomena that have been discovered in these systems. Turbulence in viscoelastic media is studied in microfluidic environments.