Add to Calendar 2025-01-23T10:00:00 2025-01-23T11:00:00 Just-in-time compiling Shor's algorithm with PennyLane and Catalyst Event Information: As quantum computing hardware continues to improve, so must the tools we use to write quantum algorithms. There is a growing need for more expressive quantum programming languages that enable developers to write code at higher levels of abstraction than quantum circuits. This, in turn, necessitates robust and automated compilers that can generate optimized sequences of quantum operations in a scalable way. Such compilers are especially important for algorithms with many interdependent classical and quantum subroutines, such as Shor's factoring algorithm. In this talk I will provide a pedagogical introduction to Shor's algorithm by presenting its implementation at varying levels of abstraction. While its high-level subroutines are straightforward to express, compilation and optimization incurs a large overhead due to the algorithm's randomized nature. To that end, I will highlight ongoing work on a fully just-in-time-compiled implementation using PennyLane and Catalyst. I'll discuss its scaling, practical resource requirements, implementation tricks (and unique quirks), and the feasibility of executing it on near-term hardware. Event Location: BRIM 311

Add to Calendar 2025-01-30T10:00:00 2025-01-30T11:00:00 Connected Network Model for the Mechanical Loss of Amorphous Materials Event Information: For over 50 years, the two-level system (TLS) model has stood as the prevailing description of thermal and acoustic properties of amorphous solids. Atomistic modeling shows that TLS are not independent as typically assumed, but form a sparse, interconnected network. I will discuss the mechanical loss in amorphous solids based on the nonequilibrium thermodynamics of connected networks, providing a major advance beyond the quintessential two-level system model, and revealing new avenues for the study amorphous materials. Amorphous mirror coatings with exceptionally low mechanical loss are critical components in the next generation of gravitational wave detectors. I will also briefly discuss how these results could impact the TLS model for dielectric loss in superconducting qubits. Event Location: BRIM 311

Add to Calendar 2025-02-06T10:00:00 2025-02-06T11:00:00 TBA Event Information: TBA Event Location: BRIM 311

Add to Calendar 2025-02-20T10:00:00 2025-02-20T11:00:00 The computational power of random quantum circuits in arbitrary geometries Event Information: Empirical evidence for a gap between the computational powers of classical and quantum computers has been provided by experiments that sample the output distributions of two-dimensional quantum circuits. Many attempts to close this gap have utilized classical simulations based on tensor network techniques, and their limitations shed light on the improvements to quantum hardware required to frustrate classical simulability. In particular, quantum computers having in excess of ∼50 qubits are primarily vulnerable to classical simulation due to restrictions on their gate fidelity and their connectivity, the latter determining how many gates are required (and therefore how much infidelity is suffered) in generating highly-entangled states. Here, we describe recent hardware upgrades to Quantinuum's H2 quantum computer enabling it to operate on up to 56 qubits with arbitrary connectivity and 99.843(5)% two-qubit gate fidelity. Utilizing the flexible connectivity of H2, we present data from random circuit sampling in highly connected geometries, doing so at unprecedented fidelities and a scale that appears to be beyond the capabilities of state-of-the-art classical algorithms. The considerable difficulty of classically simulating H2 is likely limited only by qubit number, demonstrating the promise and scalability of the QCCD architecture as continued progress is made towards building larger machines. Event Location: BRIM 311