NEW FORMS OF QUANTUM MATTER NEAR ABSOLUTE ZERO TEMPERATURE

Wolfgang Ketterle

I. M. Lifshit︠s︡, Yu. Kagan

Wolfgang Ketterle

In my talk at the workshop on fundamental physics in space I described the nanokelvin revolution which has taken place in atomic physics. Nanokelvin temperatures have given us access to new physical phenomena including Bose–Einstein condensation, quantum reflection, and fermionic superfluidity in a gas. They also enabled new techniques of preparing and manipulating cold atoms. At low temperatures, only very weak forces are needed to control the motion of atoms. This gave rise to the development of miniaturized setups including atom chips. In Earth-based experiments, gravitational forces are dominant unless they are compensated by optical and magnetic forces. The following text describes the work which I used to illustrate the nanokelvin revolution in atomic physics. Strongest emphasis is given to superfluidity in fermionic atoms. This is a prime example of how ultracold atoms are used to create well-controlled strongly interacting systems and obtain new insight into many-body physics.

Gordon Baym

Nikolay M. Nikolov, Ivan T. Todorov

Abstract Global conformal invariance (GCI) of quantum field theory (QFT) in two and higher space–time dimensions implies the Huygens’ principle, and hence, rationality of correlation functions of observable fields [16]. The conformal hamiltonian H ( has discrete spectrum and we assume that the partition function tr D qH) , q = e2πi τ, Im τ> 0 (|q | < 1) as well as the finite temperature expectation values of the field products are well defined in the finite energy space D (an assumption that is verified for free fields). We then demonstrate that the finite temperature expectation values are expressed by (doubly periodic) elliptic functions in appropriate coordinates. We compute examples of 2-point functions of free fields and study the modular transformation properties of the mean value of the energy in an equilibrium state with respect to