Caves Receives the Prestigious Micius Quantum Prize

December 16, 2020 - Ivan Deutsch

Photo of Carl CavesDistinguished Professor Emeritus Carlton Caves, and founding Director of CQuIC, is a recipient of the prestigious Micius Quantum Prize 2020 for his groundbreaking foundational work on quantum metrology and quantum information theory, especially for elucidating the fundamental noise in interferometers and its suppression with the use of squeezed states.  As a recipient he will receive a gold medal in honor of the recognition as well as a cash award.

“To all those who have worked with me throughout my life, thank you. All of you share in this prize. Whether or not we won big with our research, we had the joy of discovery and, just as important, the joy of discovery together. Working with all of you has been one of the chief things that made my life worth living,” said Caves in his remarks during the award acceptance speech.

Caves’ discovery, made in May 1980, was the first to demonstrate that the fundamental noise in interferometry comes from the vacuum (nothing) entering the unused port of an interferometer, and second, things can be improved by substituting squeezed vacuum in place of the vacuum.

“Light can be put into any interferometer in two input ports, and one of the input ports is illuminated by a coherent source, always in modern times a laser,” said Caves. “That the fundamental quantum noise comes from the vacuum entering the second, unused port is completely obvious now, but in 1980 it was not understood at all. The conventional understanding in quantum optics was that the noise in interferometry comes from the particulate nature of light—that light is made up of photons—and although this is a perfectly good explanation, like any explanation in quantum physics, it is incomplete and, importantly, it is incomplete in a way that would never lead to the idea of improving things using squeezed light.  

“Indeed, the situation was like reading a detective novel where the author carefully directs attention away from the murder scene. All of quantum optics at this time was, at least on this score, about misdirection. Don’t look at the unused port. There’s nothing there to look at.  Literally nothing. It’s vacuum. No photons. So don’t go there. Squeezing of all sorts, in optical, atomic, and optomechanical systems, is now an industry, with applications all over quantum metrology and quantum computation. It is extremely gratifying to think that my ideas on noise in interferometry lit a fuse that is now exploding all over the landscape of quantum technologies.”

Read the full story at

A transcript of Caves’ complete remarks can be found here.