Quantum fluctuation induced heat transfer between nano-mechanical membranes

Quantum vacuum fluctuations is the underlying cause of a wide range of interesting physical phenomena, experimental verifications of which have formed a firm basis for quantum field theory and QED. Recently there is theoretical prediction that quantum fluctuations of electromagnetic fields can assist phonon coupling between objects and thus facilitate heat transfer across vacuum. Here we report the first experimental observation of such a phenomenon [1]. We realized Casimir strong phonon coupling between nano-mechanical membranes and observed heat exchange between individual phonon modes. Control experiments were performed to eliminate other effects such as thermal radiation and electrostatic interaction. Our result reveals quantum fluctuations as a new heat transfer mechanism in addition to the convectional conduction, convection, and radiation. It also opens up new possibilities of exploiting quantum vacuum in thermal engineering and quantum thermodynamics.

[1] Nature 576, 243 (2019).