Can a quantum circuit detect the Unruh effect?

Title:Can a quantum circuit detect the Unruh effect?

Abstract:The Unruh effect predicts that an accelerating observer perceives the Minkowski vacuum as a thermal bath, yet direct detection remains experimentally inaccessible. Its timelike counterpart, arising from the entanglement of massless fields between the future and past light cones, offers a more feasible route but requires a detector whose transition frequency follows a specific conformal-time scaling. We propose and analyze a practical implementation of such a detector using superconducting fluxonium circuits, which naturally provide two quasi-degenerate ground states and a tunable excited state, forming an effective $\Lambda$-system. By modulating the excited-state transition frequency in Minkowski time, the detector accumulates a geometric phase associated with the timelike Unruh effect. Open-system simulations predict $\sim 10\%$ shift in the ground-state population within $530$ ns, representing a three-order-of-magnitude sensitivity enhancement over two-level Unruh-DeWitt detectors. These results establish a realistic quantum-circuit platform for experimentally probing the timelike Unruh effect and, more broadly, for testing fundamental nature of quantum fields using engineered quantum systems.

11 pages, 4 figures; Comments Welcome!

arXiv:2607.24836 [quant-ph]

(or arXiv:2607.24836v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2607.24836 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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