Quantum metrology using a single bosonic mode in circuit quantum electrodynamics

Quantum Lunch Seminar Series

Speaker: Tanjung Krisnanda
Abstract: Quantum metrology promises to surpass classical measurement limit, pushing precision toward the fundamental Heisenberg limit. However, achieving this enhancement typically requires large squeezed states or complex multiparticle entangled states, both of which are experimentally demanding and susceptible to decoherence. In this talk, I will present a versatile and deterministic protocol for quantum-enhanced parameter estimation based on two efficient state-transfer operations on a single bosonic mode. We demonstrate this approach through phase and amplitude estimation using superpositions of coherent states in a bosonic circuit QED (cQED) platform. We achieve Heisenberg-like scaling and a metrological gain of 7.5(6) dB for phase and 9.3(5) dB for amplitude estimation. Furthermore, we show that the gain and sensitivity range can be dynamically optimized by tailoring the superposition weights of the input state. Our results offer a practical and flexible route to quantum-enhanced sensing, not only for bosonic cQED devices but also for a broad class of continuous-variable quantum platforms.