Physics Colloquium

Atom-by-atom assembly with optical tweezers enables the generation of defect-free atomic arrays with flexible geometric arrangements. Combined with controlled excitation to Rydberg states, this has become a highly versatile platform for quantum computing, simulation, and metrology. I will review these developments with a focus on two valence electron atoms: The rich level structure of such atoms enables novel cooling, control, and read-out schemes, which we have used in demonstrations of record imaging and two-qubit entanglement fidelities for neutral atoms. At the same time, this direction merges high-precision spectroscopy with single-atom control resulting in a novel type of optical clock platform. Further, by applying this high-fidelity approach to many-body systems, we recently uncovered the emergence of random pure state ensembles in chaotic dynamics. Such random ensembles play an important role in quantum information science associated with device verification, supremacy tests, and quantification of complexity growth. Their generation was thought to require highly specialized evolution, e.g., using random unitary circuits. In contrast, we find that they appear in subregions of generic quantum systems, where randomization comes from quantum correlations with an intrinsic bath, a phenomenon beyond conventional quantum thermalization. As an application of this emergent randomness, we devised a fidelity estimation protocol, which generalizes cross-entropy benchmarking to much shorter evolution times and a wider range of platforms. We used this new scheme for benchmarking our quantum simulator, finding highly competitive results, and for a novel type of maximum likelihood estimation of Hamiltonian parameters.

Join Zoom Meeting

https://caltech.zoom.us/j/83117672375

Meeting ID: 831 1767 2375

One tap mobile

+16699006833,,83117672375# US (San Jose)

+12133388477,,83117672375# US (Los Angeles)