JILA Science Seminar

Digital quantum simulations and quantum error-correction protocols require the application of local gates. We demonstrate such local control in a Sr-88 tweezer array platform by locally shifting the qubit frequency using off-resonant light. This enables precise, highly parallel local Z rotations with low crosstalk. In combination with fast, recoil-free global X rotations, optimized via optimal-control techniques to minimize motional entanglement, this approach allows the local implementation of universal single-qubit gates at rates exceeding 20 kHz.

In this talk, I will discuss two recent developments centered on the physics and manipulation of hyperfine interactions in atomic and molecular systems. First, I will introduce an all-optical method for performing qudit gate operations in alkaline-earth and alkaline-earth-like atoms. Our scheme utilizes single-beam Raman transitions within the 1S0 to 3P1 manifold to achieve coherent manipulation of high-dimensional hyperfine levels, compatible with non-destructive readout and two-qudit gates via Rydberg blockade.

Quantum transducers provide a pathway to link superconducting circuits to quantum networks that extend over large distances at ambient temperatures. Here, we present our progress toward entangling a superconducting qubit in a dilution refrigerator with a time-bin encoded optical qubit propagating through a room temperature telecom fiber. Starting from a transmon qubit coupled to a microwave resonator, we generate an itinerant time-bin encoded microwave qubit entangled with the transmon.

Competition among multiple orders is a defining feature of strongly correlated matter, from frustrated magnets to high-T_c superconductors. Here, I will present two examples where quantum dynamics is governed by such multiparty competition.

Emergent quantum phases often arise when interactions extend beyond nearest neighbors, giving rise to frustration, topology, and competing orders. Dipolar quantum gases offer a uniquely tunable and microscopically controlled platform for engineering and probing such long-range quantum matter. In this talk, I present two complementary experimental platforms that advance this frontier.

Building new tools capable of studying phenomena beyond the reach of current technologies opens exciting opportunities. Quantum sensors harness the small and fragile nature of the qubits to achieve extremely precise measurements, enabling breakthroughs in fundamental physics and real-world applications by pushing resolution and sensitivity to new limits.

Topological pumps provide a powerful method for transporting particles with remarkable precision by slowly and cyclically modulating a lattice potential. This transport is topologically protected - a feature it shares with the quantum Hall effect - making it inherently robust against noise and experimental imperfections.

Neutral-atom arrays have emerged as a leading platform for scalable quantum computing, combining excellent coherence, optical control of large qubit ensembles, and flexible all-to-all connectivity. Achieving fault tolerance, however, requires efficient error detection and correction. Ytterbium offers unique advantages through its metastable-state qubits: leakage to the ground state can be independently detected, converting physical errors into erasures with known locations, while single-photon excitation to Rydberg states enables scalable, high-fidelity two qubit gates.

Many anticipated discoveries in fundamental science demand better measurement sensitivity. For acoustic sensors, mechanical dissipation sets this limit via the fluctuation-dissipation theorem. Yet, even in high-purity crystals, its microscopic origin remains poorly understood, and external enhancement, such as tension-induced dissipation dilution, is difficult to realize. Here, we realize a strain-engineered diamond nanomechanical platform using van der Waals self-assembly that harnesses surface forces to apply tensile stress exceeding 1 GPa.

A paradigmatic model in quantum metrology is the one-axis twisting Hamiltonian, comprising all-to-all Ising interactions that dynamically generate resources for entanglement-enhanced spectroscopy, notably squeezed and Schrödinger cat states.  Generalizing this approach to systems with local interactions significantly expands the range of platforms amenable to quantum-enhanced sensing.  I will report on past and ongoing experiments leveraging Rydberg interactions to realize locally interacting variants of one-axis twisting.