This is Sony, so their electrical engineers clearly know what they are doing.
But at the same time I can't understand how such a thing works using pure white noise. Feynman famously described (and disproved) a similar energy-harvesting device [0] except one that uses mechanical noise and a mechanical rectifier instead of the electrical noise and electrical rectifier of Sony. He showed that such a device will eventually stop working due to the second law of thermodynamics. Why doesn't that happen in the Sony chip?