Autonomous Dissipative Maxwell's Demon in a Diamond Spin Qutrit

Engineered dynamical maps combining coherent and dissipative transformations of quantum states with quantum measurements have demonstrated a number of technological applications, and promise to be a crucial tool in quantum thermodynamic processes. Here we exploit the control on the effective open spin qutrit dynamics of a nitrogen-vacancy center to experimentally realize an autonomous feedback process (Maxwell's demon) with tunable dissipative strength. The feedback is enabled by random measurement events that condition the subsequent dissipative evolution of the qutrit. The efficacy of the autonomous Maxwell's demon is quantified by means of a generalized Sagawa-Ueda-Tasaki relation for dissipative dynamics. To achieve this, we experimentally characterize the fluctuations of the energy exchanged between the system and its the environment. This opens the way to the implementation of a new class of Maxwell's demons, which could be useful for quantum sensing and quantum thermodynamic devices.

Automated summary

Engineered dynamical maps have shown technological applications and potential in quantum thermodynamic processes. In this study, we experimentally realized an autonomous feedback process with tunable dissipative strength by controlling the nitrogen-vacancy center. The efficacy of the feedback process was quantified using a generalized Sagawa-Ueda-Tasaki relation for dissipative dynamics.