20-Year-Old High-Temperature Superconductivity Theory Verified

A French-German team of experimental scientists, led by Philippe Bourges of the Commissariat а l'Energie Atomique, France, reports that it has verified the central prediction of a theory on high-temperature superconductivity developed by Chandra Varma, distinguished professor of physics at UC Riverside. The verification ultimately could assist in the fabrication of materials that are superconducting at room temperature and help settle a contentious, international debate on the fundamental physics of superconductivity and emergent states of matter.

Varma's initial theory, which he proposed in 1989 when he was at Bell Laboratories, stated the radical idea that high temperature superconductivity and related phenomena occur in certain materials because quantum-mechanical fluctuations in these materials increase as temperature decreases. Usually such fluctuations, which determine the properties of all matter in the universe, decrease as temperature decreases.

Varma's theory did not explain the nature of the fluctuations; he accomplished this in a theory he proposed in 1996, while still at Bell Labs, in which he noted that in copper oxide materials, also known as cuprates, superconductivity is associated with the formation of a new state of matter in which electric current loops form spontaneously, going from copper to oxygen atoms and back to copper. His theory concluded that the quantum-mechanical fluctuations are the fluctuations of these current loops. Physicists consider these fluctuations in the current loops to be fluctuations of time.