Entanglement across separate silicon dies in a modular superconducting qubit device
We demonstrate a modular solid state architecture with deterministic inter-module coupling between four physically separate, interchangeable superconducting qubit integrated circuits.
Direct pulse-level compilation of arbitrary quantum logic gates on superconducting qutrits
In this work, we demonstrate that any arbitrary qutrit gate can be realized with high fidelity. We generated and tested pulses for a large set of randomly selected arbitrary unitaries on two separate qutrit compatible processors, LLNL Quantum Device and Integration Testbed (QuDIT) standard QPU and Rigetti Aspen-11, achieving an average fidelity around 99 %.
Simulating the interplay of particle conservation and long-range coherence
We introduce two complementary probes of global and relative phase coherence, study how they are affected by measurements of the particle number, and implement them on a superconducting quantum computer by Rigetti.
Preparing quantum many-body scar states on quantum computers
Our recent work has proposed both unitary and non-unitary state preparation protocols for quantum many-body scar states and their superposition states. Their successful implementation on Aspen M-2 shows a PoC and will serve as a solid starting point for the future study of quantum many-body dynamics.
Calibrating the classical hardness of the quantum approximate optimization algorithm
Trading fidelity for scale enables approximate classical simulators such as matrix product states (MPS) to run quantum circuits beyond exact methods. A control parameter, the so-called bond dimension χ for MPS, governs the allocated computational resources and the output fidelity.
Hardware optimized parity check gates for superconducting surface codes
Our central consideration, Hardware Optimized Parity (HOP) gates, achieves stabilizer-type measurements through simultaneous multi-qubit conditional phase accumulation. Despite the multi-body effects that underpin this approach, our estimates of logical faults suggest that this design can be at least as robust to realistic noise as conventional designs.
Entanglement perspective on the quantum approximate optimization algorithm
Here, we consider the QAOA algorithm for solving the paradigmatic Max-Cut problem on different types of graphs. We study the entanglement growth and spread resulting from randomized and optimized QAOA circuits and find that there is a volume-law entanglement barrier between the initial and final states.
Synthetic weather radar using hybrid quantum-classical machine learning
We demonstrate methods to augment conventional convolutional neural networks with quantum-assisted models for generative tasks in global synthetic weather radar.
Entanglement across separate silicon dies in a modular superconducting qubit device
We demonstrate a modular solid state architecture with deterministic inter-module coupling between four physically separate, interchangeable superconducting qubit integrated circuits.
TOF-SIMS analysis of decoherence sources in Nb superconducting resonators
We utilize time-of-flight secondary ion mass spectrometry (TOF-SIMS) to understand the role specific fabrication procedures play in introducing such dissipation mechanisms in these complex systems.
Benchmarking variational quantum eigensolvers for the square-octagon-lattice Kitaev model
We consider the Kitaev spin model on a hardware-native square-octagon qubit connectivity map, and examine the possibility of efficiently probing its rich phase diagram with VQE approaches.