Reconsidering Photonic Quantum Heat Engine Efficiency

Abstract

A device -referred to as a photonic quantum heat engine -was reported in Nature Photonics [1] with an efficiency of 98 ± 4%. Moreover, in a related News & Views contribution in the same issue [2], this device was reported to exceed the Carnot limit, an extraordinary claim. As Carl Sagan once remarked, "Extraordinary claims require extraordinary evidence." Here, we outline the fundamental lack of empirical evidence that would be required to support such a claim, show that the actual efficiency of the device is ~ 0%, and bring attention to critical aspects of the operating physics of the device.