JILA X317

In this talk I will discuss the workings of the NIST timescale which generates UTC(NIST). Additionally, in support of the timescale, our group is also developing a singly-trapped ⁸⁸Sr+ ion based clock. While the S1/2 -> D5/2 transition in the ⁸⁸Sr+  ion system can support high precision, our initial goals of uncertainty at below a part in 1016 are comparatively modest. Our primary objective is rather high operational uptime in pursuit of frequent comparison with atomic clocks within the ensemble that forms the timescale.

Strain is powerful for discovery and manipulation of new phases of matter; however, elastic strains accessible to epitaxial films and bulk crystals are typically limited to small, uniform, and discrete values. In this talk I will describe our progress on synthesizing single crystalline membranes of Heusler compounds, which enable large continuously tunable strains and strain gradients via bending and rippling. This synthesis strategy borrows ideas from remote epitaxy and van der Waals epitaxy on graphene, and I will describe our current understanding of the growth mechanisms.

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.

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.

Partnerships for Informal Science Education in the Community (PISEC) is the longstanding JILA-PFC community partnership-based public engagement program. PISEC connects university volunteers with K12 youth to engage in hands-on, inquiry-based science activities and projects through afterschool clubs and in-class project-based mentorship. We seek to support youth STEM identity development and to cultivate and sustain students' interest in STEM by co-creating transformative and empowering experiences with STEM.

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.

The Kapitza pendulum, an inverted pendulum that is inherently unstable yet dynamically stabilized by high-frequency modulation of its pivot, is perhaps the most iconic example of dynamical stabilization of a single-particle system. Dynamical stabilization in the quantum many-body regime, however, remains largely unexplored, especially from an experimental perspective. In the first part of this talk, I will discuss experiments on ultracold atoms confined using time-periodic attractive and repulsive Gaussian potentials, the time average of which is zero [1] or positive.