Universal few-body physics and cluster formation

Abstract

A recent rejuvenation of experimental and theoretical interest in the physics of few- body systems has provided deep, fundamental insights into a broad range of problems. Few-body physics is a cross-cutting discipline not restricted to conventional subject ar- eas such as nuclear physics or atomic or molecular physics. To a large degree, the recent explosion of interest in this subject has been sparked by dramatic enhancements of experimental capabilities in ultracold atomic systems over the past decade, which now permit atoms and molecules to be explored deep in the quantum mechanical limit with controllable two-body interactions. This control, typically enabled by magnetic or electromagnetically-dressed Fano-Feshbach resonances, allows in particular access to the range of universal few-body physics, where two-body scattering lengths far exceed all other length scales in the problem. The Efimov effect, where 3 particles experienc- ing short-range interactions can counterintuitively exhibit an infinite number of bound or quasi-bound energy levels, is the most famous example of universality. Tremendous progress in the field of universal Efimov physics has taken off, driven particularly by a combination of experimental and theoretical studies in the past decade, and prior to the first observation in 2006, by an extensive set of theoretical studies dating back to 1970. Because experimental observations of Efimov physics have usually relied on resonances or interference phenomena in three-body recombination, this connects naturally with the processes of molecule formation in a low temperature gas of atoms or nucleons, and more generally with N-body recombination processes. Some other topics not closely related to the Efimov effect are also reviewed in this article, including ...Comment: review articl

Quantum chromodynamics (QCD)-like phase diagram with Efimov trimers and Cooper pairs in resonantly interacting SU(3) Fermi gases

“…In most of the previous works on color superfluidity [36][37][38][39][41][42][43][44], zero-range interactions have been used to describe the attraction between the three components. However, such zero-range interactions are known to lead to a collapse of the system [45,46] in connection with the existence of Efimov trimers [30,33,35,[47][48][49][50][51]. A finite range of interactions is therefore necessary to prevent the collapse and properly treat Efimov trimers.…”

Window for Efimov physics for few-body systems with finite-range interactions

“…Following the realization of the Efimov effect, much effort has been put into Efimov physics in general [8][9][10], expanding it beyond three identical bosons. These concepts are presented in the following two subsections.…”

Analytical treatment of the interaction quench dynamics of two bosons in a two-dimensional harmonic trap

“…It should be emphasized here that this is a closed form of the overlap coefficients and the only parameters that need to be determined are the energies, which are determined from the algebraic equation (8). As a result in order to obtain the time-evolution of |Ψ in νi (0) we need to numerically evaluate Eq.…”