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We prepare and analyze Rydberg states with orbital quantum numbers $\ell \le 6$using three-optical-photon electromagnetically induced transparency (EIT) and radio frequency (rf) dressing, and employ the high- $\ell$states in electric-field sensing. Rubidium-85 atoms in a room-temperature vapor cell are first promoted into the $25F_{5/2}$state via Rydberg-EIT with three infrared laser beams. Two rf dressing fields then (near-)resonantly couple the $25F, 25H(\ell =5)$, and $25I(\ell =6)$Rydberg states. The dependence of the rf-dressed Rydberg-state level structure on rf powers, rf and laser frequencies is characterized using EIT. Furthermore, we discuss the principles of dc-electric-field sensing using high- $\ell$Rydberg states and experimentally demonstrate the method using test electric fields of $\lesssim 50$V/m induced via photo-illumination of the vapor-cell wall. We measure the highly nonlinear dependence of the dc-electric-field strength on the power of the photo-illumination laser. Numerical calculations, which reproduce our experimental observations well, elucidate the underlying physics. Our paper is relevant to high-precision spectroscopy of high- $\ell$Rydberg states, Rydberg-atom-based electric-field sensing, and plasma electric-field diagnostics. Published by the American Physical Society2024 

We investigate the possible realization of an ultracold-atom rotation sensor that is based on recently proposed tractor atom interferometry (TAI). An experimental design that includes the generation of a Laguerre–Gaussian-beam-based “pinwheel” optical lattice and multi-loop interferometric cycles is discussed. Numerical simulations of the proposed system demonstrate TAI rotation sensitivity comparable to that of contemporary matter-wave interferometers. We analyze a regime of TAI rotation sensors in which nonadiabatic effects may hinder the system's performance. We apply quantum optimal control to devise a methodology suitable to address this nonadiabaticity. Our studies are of interest for current efforts to realize compact and robust matter-wave rotation sensors, as well as for fundamental physics applications of TAI. 

We report a measurement of the dynamic (ac) scalar polarizability of the 5D3/2 state in 85Rb atoms at a laser wavelength of 1064 nm. Contrary to a recent measurement in Phys. Rev. A 104, 063304 (2021), the experiments are performed in a low-intensity regime in which the ac shift is less than the 5D3/2 state’s hyperfine structure, as utilized in numerous experiments with cold, trapped atoms. The extracted ac polarizability is α5D3/2=−499±59 a.u., within the uncertainty of the aforementioned previous result. The calibration of the 1064 nm light intensity, performed by analyzing light shifts of the D1 line, is the main source of uncertainty. Our results are useful for applications of the Rb 5D3/2 state in metrology, quantum sensing, and fundamental-physics research on Rydberg atoms and molecules. 

Abstract Avoided crossings of level pairs with opposite slopes can form potential-energy minima for the external degree of freedom of quantum particles, giving rise to metastable states on the avoided crossings (MSACs). Nonadiabatic decay of MSACs is studied by solving the two-component Schrödinger equation in diabatic and adiabatic representations. Non-perturbative lifetime values are found by evaluating wave function flux and scattering phases of time-independent solutions, as well as wave-function decay of time-dependent solutions. The values from these methods generally agree well, validating the utilized approaches. As the adiabaticity parameter, V , of the system is increased by about a factor of ten across the mixed diabatic/adiabatic regime, the MSAC character transitions from marginally to highly stable, with the lifetimes increasing by about ten orders of magnitude. The dependence of MSAC lifetime on the vibrational quantum number, ν , is discussed for several regimes of V . Time-dependent perturbation theory yields lifetimes that deviate by ≲30% from non-perturbative results, over the range of V and ν studied, while a semi-classical model based on Landau–Zener tunneling is up to a factor of twenty off. The results are relevant to numerous atomic and molecular systems with metastable states on intersecting, coupled potential energy curves. 

Abstract We present principles and possible design concepts for a tractor atom interferometer (TAI) based on three-dimensional confinement and transport of ultracold atoms. The confinement reduces device size and wave-packet dispersion, enables arbitrary holding times, and facilitates control to create complex trajectories that allow for optimization to enable fast splitting and recombination, to suppress detrimental nonadiabatic excitation, and to cancel unwanted sensitivity. Thus, the design allows for further advancement of compact, high-sensitivity, quantum sensing technology. In particular, we focus on the implementation of quantum-enhanced accelerometers and gyroscopes. We discuss TAI protocols for both spin-dependent and scalar trapping potentials. Using optimal control theory, we demonstrate the splitting of the wave function on a time scale two orders of magnitude shorter than a previous proposal using adiabatic dynamics, thus maximizing the time spent at full separation, where the interferometric phase is accumulated. The performance estimates for TAI give a promising perspective for atom-interferometry-based sensing, significantly exceeding the sensitivities of current state-of-the-art devices. 

Abstract We present calculations of the photoionization (PI) cross sections of rubidium and cesium Rydberg atoms for light with wavelengths ranging from the infrared to the ultraviolet, using model potentials from Marinescu et al (1994 Phys. Rev. A 49 982). The origins of pronounced PI minima are identified by investigating the free-electron wavefunctions. These include broad PI minima in the nS to ϵP PI channels of both Rb and Cs, with free-electron energy ϵ , which are identified as Cooper minima. Much narrower PI minima in the nD to ϵF channels are due to shape resonances of the free-electron states. We describe possible experimental procedures for measuring the PI minima, and we discuss their implications in fundamental atomic physics as well as in practical applications. Measurements of PI cross sections of Rydberg atoms may serve as a sensitive probe for many-electron interactions of the Rydberg electron in the atomic core region.