17 research outputs found
Scanning electron microscopy of Rydberg-excited Bose-Einstein condensates
We report on the realization of high resolution electron microscopy of
Rydberg-excited ultracold atomic samples. The implementation of an ultraviolet
laser system allows us to excite the atom, with a single-photon transition, to
Rydberg states. By using the electron microscopy technique during the Rydberg
excitation of the atoms, we observe a giant enhancement in the production of
ions. This is due to -changing collisions, which broaden the Rydberg level
and therefore increase the excitation rate of Rydberg atoms. Our results pave
the way for the high resolution spatial detection of Rydberg atoms in an atomic
sample
Continuous Coupling of Ultracold Atoms to an Ionic Plasma via Rydberg Excitation
We characterize the two-photon excitation of an ultracold gas of Rubidium
atoms to Rydberg states analysing the induced atomic losses from an optical
dipole trap. Extending the duration of the Rydberg excitation to several ms,
the ground state atoms are continuously coupled to the formed positively
charged plasma. In this regime we measure the -dependence of the blockade
effect and we characterise the interaction of the excited states and the ground
state with the plasma. We also investigate the influence of the
quasi-electrostatic trapping potential on the system, confirming the validity
of the ponderomotive model for states with
Bistability Versus Metastability in Driven Dissipative Rydberg Gases
We investigate the possibility of a bistable phase in an open many-body system. To this end, we discuss the microscopic dynamics of a continuously off-resonantly driven Rydberg lattice gas in the regime of strong decoherence. Our experimental results reveal a prolongation of the temporal correlations exceeding the lifetime of a single Rydberg excitation and show strong evidence for the formation of finite-sized Rydberg excitation clusters in the steady state. We simulate the dynamics of the system using a simplified and a full many-body rate-equation model. The results are compatible with the formation of metastable states associated with a bimodal counting distribution as well as dynamic hysteresis. However, a scaling analysis reveals that the correlation times remain finite for all relevant system parameters, which suggests the formation of many small Rydberg clusters and finite correlation lengths of Rydberg excitations. These results constitute strong evidence against the presence of a global bistable phase previously suggested to exist in this system