We present an introductory review of the latest advancements cold Rydberg atom research. First, we briefly summarize the exaggerated properties of Rydberg atoms, and we discuss the new perspectives of Rydberg atom research that has been enabled by laser cooling and trapping technique. We then highlight the latest developments and achievements in the newly emerged research fields for Rydberg mol...

Coupling photons to Rydberg excitations in a cold atomic gas yields unprecedentedly large optical nonlinearities at the level of individual light quanta. Here, the basic mechanism exploits the strong interactions between Rydberg atoms to block the formation of nearby dark-state polaritons. However, the dissipation associated with this mechanism ultimately limits the performance of many practica...

Photodissociation dynamics of HBr at a series of photolysis wavelengths in the range of 123.90-125.90 nm and at around 137.0 nm have been studied using the H atom Rydberg "tagging" time-of-flight technique. The branching fractions between the channels forming ground Br((2)P3/2) and spin-orbit excited Br((2)P1/2) atoms together with the angular distributions of the products corresponding to thes...

We theoretically demonstrate a viable approach to spin squeezing in optical lattice clocks via optical dressing of one clock state to a highly excited Rydberg state, generating switchable atomic interactions. For realistic experimental parameters, these interactions are shown to generate over 10 dB of squeezing in large ensembles within a few microseconds and without degrading the subsequent cl...

The existence of a mediating state for the ultrafast electronic relaxation in ethylenic-like molecules has been shown by femtosecond electron imaging techniques. This state is of Rydberg character, and its high efficiency is due to its ability to link the electron distributions of the initial and final electronic states.

When an excited atomic electron interacts with a neutral perturbing atom or molecule that possesses a shape resonance, it generates a characteristic class of Born–Oppenheimer potential curves that rise with internuclear distance. We document this effect, and predict the existence of a diverse class of stable, strongly bound atom–atom and atom–molecule states that result from this phenomenon. Fo...

Rotationally resolved photoelectron spectra from vibrational autoionization of individual rotational levels of the nlR v 1, 11 n 15, 0 lR 3 Rydberg states of NO are measured by combining two-color double-resonance excitation via the NO A 2 v i 1, Ni 19 state with time-of-flight photoelectron spectroscopy. The photoelectron spectra show that both even-l and odd-l continuum partial waves are gene...

We theoretically investigate light propagation and electromagnetically induced transparency in a quasi-one-dimensional gas in which atoms interact strongly via exchange interactions. We focus on the case in which the gas is initially prepared in a many-body state that contains a single excitation and conduct a detailed study of the absorptive and dispersive properties of such a medium. This sce...

A longstanding goal in chemical physics has been the control of atoms and molecules using coherent light fields. This paper provides a brief overview of the field and discusses experiments that use a programmable pulse shaper to control the quantum state of electronic wavepackets in Rydberg atoms and electronic and nuclear dynamics in molecular liquids. The shape of Rydberg wavepackets was cont...

Strong interaction between two single photons is a long standing and important goal in quantum photonics. This would enable a new regime of nonlinear optics and unlock several applications in quantum information science, including photonic quantum gates and deterministic Bell-state measurements. In the context of quantum networks, it would be important to achieve interactions between single pho...