Group members:

Servaas Kokkelmans, s.kokkelmans [at] tue.nl, Principal Investigator. Here is a Short CV, and here a List of presentations.

Maikel Goosen, m.r.goosen [at] tue.nl, Ph.D student

Rick van Bijnen, R.M.W.v.Bijnen [at] tue.nl, Ph.D student, personal website

Sjoerd Smit, s.smit [at] student.tue.nl, Master thesis student

Marije Haverhals, m.m.haverhals [at] student.tue.nl, Master thesis student

Jaron Sanders, j.sanders [at] student.tue.nl, Master thesis student


Former group members:


Elmer Doggen, e.v.h.doggen [at] student.tue.nl, Master thesis student

Jim Portegies, Master thesis student, now Ph.D student at Courant Institute, New York

Bout Marcelis, Ph.D student, now researcher at Philips labs, Eindhoven

Eric van Kempen, Ph.D student, now researcher at Philips labs, Eindhoven

Leon van Dijk, l.p.v.dijk [at] tue.nl, Master thesis student, now Ph.D student in group P. Bobbert, Eindhoven

Johan Mentink, Master thesis student, now Ph.D student in group Theo Rasing, Nijmegen



The former atomic physics theory group was headed by Prof. Verhaar (now retired).

Latest News:

Creation of Rydberg Crystals

Ultracold atomic gases have been used extensively in recent years to realize textbook examples of condensed matter phenomena. Recently, phase transitions to ordered structures have been predicted for gases of highly excited, 'frozen' Rydberg atoms. Such Rydberg crystals are a model for dilute metallic solids with tunable lattice parameters, and provide access to a wide variety of fundamental phenomena. We investigate theoretically how such structures can be created in four distinct cold atomic systems, by using tailored laser-excitation in the presence of strong Rydberg-Rydberg interactions. We study in detail the experimental requirements and limitations for these systems, and characterize the basic properties of small crystalline Rydberg structures in one, two and three dimensions: arXiv:1103.2096

Collapsing Bose-Einstein Condensates

We describe a model of dynamic Bose-Einstein condensates near a Feshbach resonance that is computationally feasible under assumptions of spherical or cylindrical symmetry. Simulations in spherical symmetry approximate the experimentally measured time to collapse of an unstably attractive condensate, suggesting that the quantum fluctuations and atom-molecule pairing included in the model are the dominant mechanisms during collapse. Simulations of condensates with repulsive interactions find some quantitative disagreement, suggesting that pairing and quantum fluctuations are not the only significant factors for condensate loss or burst formation. Inclusion of three-body recombination was found to be inconsequential in all of our simulations:  arXiv:1102.2104

Efimov Trimers in a Harmonic Potential

We study the Efimov effect in a harmonic oscillator in the hyperspherical formulation, and show how a reduced model allows for a description that is a generalization of the Efimov effect in free space and leads to results that are easily interpreted. Efimov physics may be observed by varying the value of the scattering length, since in the regime where the trimers have a mixed harmonic oscillator and Efimov character, the inelastic properties of these states are still manageable. The model also allows for the study of non-universal Efimov trimers by including the effective range scattering parameter. While we find that in a certain regime the effective range parameter can take over the role of the three-body parameter, interestingly, we obtain a numerical relationship between these two parameters different from what was found in other models:  arXiv:1101.0696

Synthetic hydrodynamics in Bose-Einstein condensates

Engineering of synthetic magnetic flux in Bose-Einstein condensates [Lin et al., Nature 462, 628 (2009)] has prospects for attaining the high vortex densities necessary to emulate the fractional quantum Hall effect. We analytically establish the hydrodynamical behaviour of a condensate in a uniform synthetic magnetic field, including its density and velocity profile. Importantly, we find that the onset of vortex nucleation observed experimentally corresponds to a dynamical instability in the hydrodynamical solutions and reveal other routes to instability and anticipated vortex nucleation. arXiv:1011.4315