2024/04/22 by Olli Mansikkamäki, Alexander C. Tyner, Mansikkamäki, Olli +7 · 1 citation
Physics and Astronomy · #Atomic and Subatomic Physics Research #FOS: Physical sciences #Quantum Physics (quant-ph) #Quantum and electron transport phenomena
paper · pdf · doi:10.48550/arxiv.2404.14039
openalex publication_date 2024/04/22 · openalex created_date 2024/04/24 · openalex updated_date 2026/07/28
Two-level systems (TLS) of unclear physical origin are a major contributor to decoherence in superconducting qubits. The interactions of individual TLS with a qubit can be detected via various spectroscopic methods, most of which have relied on the tunability of the qubit frequency. We propose a novel method that requires only a microwave drive and dispersive readout, and thus also works fixed-frequency qubits. The proposed two-tone spectroscopy involves a microwave pulse of varying frequency and length to excite TLSs of unknown frequencies, followed by a second pulse at the qubit frequency. TLS parameters can be estimated from the qubit population as a function of the first pulse frequency and length.