Programmable Heisenberg interactions between Floquet qubits

Journal Article · 15 January 2024 · Nature Physics

DOI: https://doi.org/10.1038/s41567-023-02326-7 · OSTI ID:2281416

Nguyen, Long B. ; Kim, Yosep ; Hashim, Akel ; Goss, Noah ; Marinelli, Brian ; Bhandari, Bibek ; Das, Debmalya ; Naik, Ravi K. ; Kreikebaum, John Mark ; Jordan, Andrew N.; Santiago, David I. ; Siddiqi, Irfan

Abstract The trade-off between robustness and tunability is a central challenge in the pursuit of quantum simulation and fault-tolerant quantum computation. In particular, quantum architectures are often designed to achieve high coherence at the expense of tunability. Many current qubit designs have fixed energy levels and consequently limited types of controllable interactions. Here by adiabatically transforming fixed-frequency superconducting circuits into modifiable Floquet qubits, we demonstrate an XXZ Heisenberg interaction with fully adjustable anisotropy. This interaction model can act as the primitive for an expressive set of quantum operations, but is also the basis for quantum simulations of spin systems. To illustrate the robustness and versatility of our Floquet protocol, we tailor the Heisenberg Hamiltonian and implement two-qubit iSWAP, CZ and SWAP gates with good estimated fidelities. In addition, we implement a Heisenberg interaction between higher energy levels and employ it to construct a three-qubit CCZ gate, also with a competitive fidelity. Our protocol applies to multiple fixed-frequency high-coherence platforms, providing a collection of interactions for high-performance quantum information processing. It also establishes the potential of the Floquet framework as a tool for exploring quantum electrodynamics and optimal control.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: Korea Institute of Science and Technology (KIST); US Army Research Office (ARO); USDOE; USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 2281416
• Journal Information: Nature Physics, Journal Name: Nature Physics Journal Issue: 2 Vol. 20; ISSN 1745-2473
• Publisher: Nature Publishing GroupCopyright Statement
• Country of Publication: France
• Language: English