Rydberg excitation of a Bose-Einstein condensate

10.1088/1742-6596/594/1/012041Journal of Physics: Conference Series59411204

Quantum State Transmission in a Superconducting Charge Qubit-Atom Hybrid

10.1038/srep38356Scientific Reports63835

Excitation dynamics and full counting statistics for resonant and off-resonant excitation of a strongly correlated cold Rydberg gas

Atoms in high-lying Rydberg states strongly interact with each other via the dipole-dipole or van der-Waals potential thus permitting the exploration of a wide range of many-body phenomena in strongly interacting systems. The strong interactions between Rydberg atoms under resonant laser driving become manifest either as spatial correlations compatible with a radius of blockade around an excited atom or through a reduction of fluctuations leading to sub-Poissonian statistics [1]. On the other hand, away from resonance, the detuning can compensate for the energy shift induced by the Rydberg-Rydberg interaction, giving rise to resonant interaction processes [2, 3]. In such an off-resonant excitation scheme, two atoms can undergo a pair excitation if the atomic interaction matches the laser energy defect/excess. As a consequence an already excited Rydberg atom pair (or a Rydberg atom, off-resonantly excited) can shift other atoms into resonance [4], in a domino effect, leading to an increasing overall number of Rydberg excitations. This resonant condition is the opposite of the blockade effect, where the interactions suppresses excitations, allowing at most one single excitation within a blockade radius. I will present experimental observations for both the resonant and the off-resonant excitation scheme, with the excitation laser having a finite detuning from the 87Rb 70S state. I will illustrate the off-resonant excitation dynamics and full counting statistics in experiments in which the growth of excitations is controlled by using an initial Rydberg excitation as a seed. The information extracted from the full counting distribution makes possible a direct comparison with theoretical predictions that is far more sensitive than, i.e., the mean and standard deviation alone

Strongly correlated excitation dynamics in cold Rydberg gases

Strongly correlated excitation dynamics in cold Rydberg gase

Corrigendum: Quantum State Transmission in a Superconducting Charge Qubit-Atom Hybrid

10.1038/srep46910Scientific reports74691

Strongly correlated excitation dynamics in an ultracold Rydberg gas

The van-der-Waals interaction between ultracold atoms excited to highlying Rydberg states can lead to strongly correlated excitation dynamics [1, 2]. We study these correlations for resonant and off-resonant driving of cold atoms in a magneto-optical trap. In the resonant case we observe dynamical constraints similar to those found in glassy systems [3]. By contrast, for off-resonant driving facilitated excitations mediated by Rydberg-Rydberg interactions lead to avalanche-like events in which a chain reaction of successive excitations occurs. We show that this effect can be induced by a seed excitation and that the resulting full counting statistics of excitation events can be reproduced by a simple analytical model

Correlated excitation dynamics in an ultracold Rydberg gas

No abstract available

An atomtronic flux qubit: A ring lattice of Bose-Einstein condensates interrupted by three weak links

10.1088/1367-2630/18/7/075013New Journal of Physics1877501

An atomtronic flux qubit: A ring lattice of Bose-Einstein condensates interrupted by three weak links

International audienceWe study a physical system consisting of a Bose-Einstein condensate confined to a ring shaped lattice potential interrupted by three weak links. The system is assumed to be driven by an effective flux piercing the ring lattice. By employing path integral techniques, we explore the effective quantum dynamics of the system in a pure quantum phase dynamics regime. Moreover, the effects of the density's quantum fluctuations are studied through exact diagonalization analysis of the spectroscopy of the Bose-Hubbard model. We demonstrate that a clear two-level system emerges by tuning the magnetic flux at degeneracy. The lattice confinement, platform for the condensate, is realized experimentally employing a spatial light modulator. © 2016 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft