Regensburg 2019 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 58: Superconductivity: Qubits 2

TT 58.1: Talk

Thursday, April 4, 2019, 15:00–15:15, Theater

Observation and stabilization of photonic Fock states in a hot radio-frequency resonator — Mario F. Gely¹, •Christian Dickel¹, Marios Kounalakis¹, Jacob Dalle¹, Remy Vatre¹, Brian Baker², Mark D. Jenkins¹, and Gary A. Steele¹ — ¹Kavli Institut of Nanoscience, Delft University of Technology, The Netherlands — ²Department of Physics and Astronomy, Northwestern University, United States of America

Detecting weak radio-frequency electromagnetic fields plays a crucial role in a wide range of fields, from radio astronomy to nuclear magnetic resonance imaging. In quantum mechanics, the ultimate limit of a weak field is a single-photon. Detecting and manipulating single-photons at megahertz frequencies present a challenge as, even at millikelvin temperatures, thermal fluctuations are significant. Here, we use a superconducting transmon qubit to directly observe photon-number splitting of the transition frequency due to a megahertz electrical resonator. Using the qubit, we achieve quantum control over thermal photons, sideband cooling the system and stabilizing photonic Fock states. Releasing the resonator from our control, we directly observe its re-thermalization with nanosecond resolution. Extending circuit quantum electrodynamics to a new regime, we enable the exploration of thermodynamics with photon-number resolution and allow interfacing quantum circuits with megahertz systems, for example, electro-mechanical oscillators.