20231117 A superconducting quantum simulator based on a photonic-bandgap metamaterial

A superconducting quantum simulator based on a photonic-bandgap metamaterial

Eunjong Kim
Assistant Professor, Department of Physics & Astronomy, Seoul National University

Experimental realizations of engineerable quantum systems provide insights into exotic
quantum many-body concepts that are intractable with available classical methods. A key
challenge in the development of modern quantum simulators is to maintain the level of
connectivity and control during scale-up. While majority of scalable quantum simulation and
computation architectures to date feature nearest-neighbor interactions limited by their local
nature of coupling, long-range interacting quantum systems—exhibiting fast build-up of
quantum correlation and entanglement—provide new approaches for studying quantum manybody
phenomena and investigating quantum error-correction schemes in the near term.
Utilization of extensible quantum bus such as a photonic waveguide provides a natural
direction to investigate such many-body quantum systems where qubits interact non-locally by
exchange of photons along the bus. Following this idea, here we demonstrate a 10-qubit
superconducting quantum simulator [1] with tunable long-range connectivity and individual
addressing, constructed from a scalable metamaterial-based waveguide with photonic
bandgaps. We study many-body quench dynamics showing a crossover between integrability
and ergodicity, enabled by the various hopping range realized in our system. The widely tunable
range of parameters demonstrated in our work enables study of different regimes of quantum
chaos and thermalization, and more broadly, provides a novel class of accessible Hamiltonians
for analog quantum simulation in superconducting circuits.

[1] X. Zhang*, E. Kim* et al., Science 379, 278-283 (2023)