Faculty @ CNRS, University Paris-Sud, University Paris-Saclay, France
Tuesday June 28 – 14.00 BST
Coherence-powered work exchanges between a solid-state qubit and light fields
We explore how quantum coherence impacts energy exchanges between a solid-state quantum bit and light fields. Following pioneering theoretical frameworks, we first experimentally study the work transferred during the spontaneous emission of a solid-state qubit into a reservoir of modes of the electromagnetic field. This step energetically corresponds to the charging of a quantum battery and we show that the amount of transferred work is proportional to the initial quantum coherence of the qubit, and is reduced at higher temperatures. In a second step, we study the discharge of the battery and its energy transfer to a classical- i.e.- laser field using homodyne-type measurements. We demonstrate that the amount of energy and work transferred to the laser field is controlled by the relative classical optical phase between the two fields, the quantum purity of the charged battery field as theoretically predicted, as well as long-term fluctuations in the qubit solid-state environment.