Two-Level System as a Quantum Sensor for Absolute Calibration of Power

Abstract

A two-level quantum system can absorb or emit not more than one photon at a time. Using this fundamental property, we demonstrate how a superconducting quantum system strongly coupled to a transmission line can be used as a sensor of the photon flux. We propose four methods and analyse them for the absolute calibration of power by measuring spectra of scattered radiation from the twolevel system. Our results suggest that the absolute power calibration is independent of dephasing as long as its non-radiative relaxation is negligible. Our approach can be used for practical applications for example in calibration of transmission lines within dilution refrigerators. arXiv:1905.05104v1 [quant-ph]

Dissipation-Based Quantum Sensing of Magnons with a Superconducting Qubit

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“…This property is leveraged in quantum sensing, where appropriate quantum systems can be monitored to detect a signal [1]. Superconducting qubits are attractive candidates for quantum sensors [1][2][3][4][5][6][7][8] as their large electric dipole moment enables strong coupling to electromagnetic fields [9,10]. Recent developments of hybrid quantum systems extend the range of applicability of qubits as quantum sensors through coupling the qubits to additional degrees of freedom [11][12][13][14][15][16].…”

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“…The Mollow triplet structure has been observed in atomic beams [3], ions [4], single molecules [5], quantum dots [6][7][8][9], superconducting qubits [10], and cold atoms [11]. Its potential applications, such as heralded single-photon sources [12], quantum sensing [13][14][15], and spin noise characterization [16], make it a versatile tool in physics.…”

“…Previous the-* gq_wang@mit.edu † pcappell@mit.edu oretical studies beyond the RWA have predicted frequency shifts, imbalanced sidebands, and high-order frequency components [20][21][22], yet experimental verification is still lacking. The aim of this paper is to experimentally explore the Mollow triplet structure in the regime beyond the RWA, thus providing further insights into its theory and applications (e.g., to coherent control [23] and quantum sensing [13][14][15]. )…”

Amplitude and frequency sensing of microwave fields with a superconducting transmon qudit

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