Observation and stabilization of photonic Fock states in a hot radio-frequency resonator*

Detecting and manipulating single-photons at MHz frequencies presents a challenge as, even at cryogenic temperatures, thermal fluctuations are significant. In our work [1], we use a GHz superconducting qubit to directly observe the quantization of a MHz radio-frequency electromagnetic field. Using the qubit, we achieve quantum control over thermal photons, cooling to the ground-state and stabilizing photonic Fock states. Releasing the resonator from our control, we directly observe its re-thermalization dynamics with the bath with nanosecond resolution. Extending circuit QED to a new regime, we enable the exploration of thermodynamics at the quantum scale and allow interfacing quantum circuits with MHz systems such as spins or mechanical oscillators. The tool used to design such a circuit, QuCAT [2], the "quantum circuit analyzer tool in Python" will also be featured in this poster.
[1] Science 363.6431 (2019): 1072-1075.
[2] arXiv:1908.10342 (2019).