Direct observation of ultrafast many-body electron dynamics in an ultracold Rydberg gas

Abstract

Many-body correlations govern a variety of important quantum phenomena such as the emergence of superconductivity and magnetism. Understanding quantum many-body systems is thus one of the central goals of modern sciences. Here we demonstrate an experimental approach towards this goal by utilizing an ultracold Rydberg gas generated with a broadband picosecond laser pulse. We follow the ultrafast evolution of its electronic coherence by time-domain Ramsey interferometry with attosecond precision. The observed electronic coherence shows an ultrafast oscillation with a period of 1 femtosecond, whose phase shift on the attosecond timescale is consistent with many-body correlations among Rydberg atoms beyond mean-field approximations. This coherent and ultrafast many-body dynamics is actively controlled by tuning the orbital size and population of the Rydberg state, as well as the mean atomic distance. Our approach will offer a versatile platform to observe and manipulate non-equilibrium dynamics of quantum many-body systems on the ultrafast timescale.

Absolute strong-field ionization probabilities of ultracold rubidium atoms

“…This is beneficial for electron or ion spectroscopy after ionization [35] which can reveal further insight into strong-field physics in alkali atoms. Our experimental techniques can also be used for absolute calibration of detector efficiencies in the rapidly growing number of experiments using cold atoms with charged particle detection [11][12][13][36][37][38].…”

A generalized phase space approach for solving quantum spin dynamics

“…In particular, models of coupled spin-particles with long-range interactions have become a topic of intensive research because of important experimental progress. While models with spin S=1/2 have been implemented with many different setups, e.g.using polar molecules [15,17], Rydberg atoms [16,[18][19][20][21][22][23], trapped ions [24][25][26] and cavity QED systems [27,28], recently also models with larger spins S>1/2 have become a research focus in particular for experiments with magnetic atoms [29][30][31][32][33][34]. The large spin degrees of freedom in S>1/2 systems poses a much more stringent requirement for numerical treatment compared to S=1/2 systems.…”

Effects of long-range hopping and interactions on quantum walks in ordered and disordered lattices

“…However, the excitations of polar molecules in optical lattices, are characterized by the tunnelling amplitudes that decay as t ij ∝ |r ij | −3 , where r ij is the distance between the sites i and j, thus allowing for direct transitions between distant lattice sites. Quasi-particles with such tunnelling properties also arise in experiments probing excitonic energy transfer in molecular crystals [49], molecular aggregates [50], photo-sythetic complexes [51][52][53][54][55][56][57], artificial light-harvesting materials [58], and ensembles of Rydberg atoms [32,59]. The long-range tunnelling amplitudes are known to have a significant effect on the dynamical properties of quantum particles in lattice po-tentials [60][61][62][63][64][65][66].…”