Spin-Motion Coupling and Collective Phenomena in Rydberg Atom Systems: From Thermal Vapors to Engineered Tweezer Arrays

Abstract

Synthetic quantum systems based on neutral Rydberg atoms are versatile platforms for studying quantum many-body physics. This cumulative dissertation investigates them across scenarios of progressively increasing microscopic control. The first studies refine the control over the atoms and their interactions: from disordered thermal vapors accessible only through collective averages, through structured lattice gases with single-atom resolution, to one-dimensional tweezer arrays of individually positioned atoms. The later studies then extend this control to the optical traps, the laser drive, and ultimately the quantized motion of the atoms themselves. Along this progression, each gain in control unlocks qualitatively new many-body phenomena and applications.

At the lowest level of control, a thermal Rydberg vapor already exhibits exploitable collective behavior. Driven through a regime of optical bistability, it serves as a physical reservoir for time-series prediction. The learning performance peaks near the nonequilibrium phase transition where the collective response is amplified. Gaining single-atom resolution opens access to constrained many-body physics. In two-dimensional Rydberg lattice gases, resonant facilitation conditions based on the strong Rydberg interactions impose kinetic constraints that fragment the Hilbert space. The resulting Hilbert-space sectors support distinct elementary excitations whose spectroscopic signatures exhibit collective many-body enhancement. Narrowing the geometry to one-dimensional tweezer arrays enables precise engineering of coherent transport, and raises the question of what the resulting long-range correlations are good for. A chain of Rydberg atoms is shown to extend quantum correlations to massive objects: it mediates entanglement between two spatially separated mechanical oscillators, through both coherent dynamics and a dissipative scheme exploiting tunable Rydberg decay.

Having considered several scenarios based primarily on controlling atomic positions and interactions, the remaining studies turn to additional degrees of freedom beginning with the fields that trap the atoms. Rydberg-mediated operations require long-lived coherence, which is limited by differential AC Stark shifts from the trapping fields. A study of magic trapping reveals that the optimal detuning differs between running-wave and standing-wave configurations because the extended Rydberg electron wave function resolves the spatial structure of the trapping field. With trapping under control, the remaining frontier is the coupling between electronic excitation and atomic motion, typically a source of decoherence but exploited here as a programmable resource. Stroboscopic Rydberg dressing protocols convert spin-motion coupling into effective multi-body interactions, whose character is tuned by the pulse timing relative to the atomic motion. Harnessed actively, the same coupling drives the collective motion of an atom chain into squeezed states, reducing interatomic distance fluctuations to a fraction of the ground-state value and producing non-classical states with substantial Wigner negativity.

Together, these studies demonstrate how progressively refining control over the interactions, positions, traps, and motion of Rydberg atoms makes the platform an increasingly powerful setting for studying quantum many-body physics.