Quantum jitter lets heat travel across a vacuum
For the first time, scientists have measured the heat transferred by the quantum effervescence of empty space. Two tiny, vibrating membranes reached the same temperature despite being separated by a vacuum, physicists report in the Dec. 12 Nature. The result is the first experimental demonstration of a predicted but elusive type of heat transfer. Normally, a vacuum prevents most types of heat transfer — that helps a vacuum-sealed thermos keep coffee piping hot. But “quantum mechanics gives you a new way for heat to go through” a vacuum, says coauthor King Yan Fong, a physicist who worked on the study while at the University of California, Berkeley. For distances on the scale of nanometers, heat can be transferred through a vacuum via quantum fluctuations, a kind of churning of transient particles and fields that occurs even in empty space (SN: 11/13/16). Made of gold-coated silicon nitride, the two membranes each measured about 300 micrometers across. The researchers cooled one membrane and heated...