An experimental approach for investigating many-body phenomena in Rydberg-interacting quantum systems

Abstract

Recent developments in the study of ultracold Rydberg gases demand an advanced level of experimental sophistication, in which high atomic and optical densities must be combined with excellent control of external fields and sensitive Rydberg atom detection. We describe a tailored experimental system used to produce and study Rydberg-interacting atoms excited from dense ultracold atomic gases. The experiment has been optimized for fast duty cycles using a high flux cold atom source and a three beam optical dipole trap. The latter enables tuning of the atomic density and temperature over several orders of magnitude, all the way to the Bose-Einstein condensation transition. An electrode structure surrounding the atoms allows for precise control over electric fields and single-particle sensitive field ionization detection of Rydberg atoms. We review two experiments which highlight the influence of strong Rydberg-Rydberg interactions on different many-body systems. First, the Rydberg blockade effect is used to pre-structure an atomic gas prior to its spontaneous evolution into an ultracold plasma. Second, hybrid states of photons and atoms called dark-state polaritons are studied. By looking at the statistical distribution of Rydberg excited atoms we reveal correlations between dark-state polaritons. These experiments will ultimately provide a deeper understanding of many-body phenomena in strongly-interacting regimes, including the study of strongly-coupled plasmas and interfaces between atoms and light at the quantum level.

Measurement of many-body chaos using a quantum clock

“…Finally we also note that such a checkerboard-lattice setup can also be implemented with Rydberg atoms, where an additional ancilla atom is dispersively coupled only to the sublattice serving as passive couplers through the Rydberg blockade mechanism [30,[36][37][38]. Such a partial addressing scheme has been discussed in a recent work about measuring entanglement spectrum with Rydberg atoms [42].…”

“…The ancilla qubit can be either the cavity photon mode or the internal state of an atom. The mechanism of the coupling is usually through dispersive interaction, which can originate, for example from Jaynes-Cummings interaction [34] perturbatively [16,20,35], or from Rydberg blockade mechanism [30,[36][37][38]. Such an ancilla has been widely used as control-phase gate [30,[35][36][37][38] for quantum information processing.…”

“…The mechanism of the coupling is usually through dispersive interaction, which can originate, for example from Jaynes-Cummings interaction [34] perturbatively [16,20,35], or from Rydberg blockade mechanism [30,[36][37][38]. Such an ancilla has been widely used as control-phase gate [30,[35][36][37][38] for quantum information processing. Meanwhile, theoretical proposals suggest that such an ancilla can be used as a quantum switch that performs a many-body Ramsey interferometer [39,40] to extract useful information of the quantum system, such as en-tanglement entropy [41] and spectrum [42].…”

A high repetition rate experimental setup for quantum non-linear optics with cold Rydberg atoms

“…This allows to maintain typical pressures below 10 −10 mbar in the main science chamber. The 2D MOT setup realised and presented below is based on a design by Hofmann et al [42].…”

“…Vacuum inside the cell is maintained through a 149 mm long differential pumping tube with an inner diameter of 6 mm and a 0.8 mm diameter aperture at the 2D MOT end to velocity select the slow atoms in the atomic beam. The aperture size was chosen based on other designs [42] to allow for a high atomic flux on the order of 10 9 s −1 to pass while at the same time preventing undesired leakage of atoms into the main science chamber and maintaining sufficiently good vacuum on the 2D MOT side without a large ion pump. To permit independent vacuum breaks, a gate valve is placed between the 2D MOT section and the main science chamber.…”