Prof brings physics to life in talk

In the fifth century B.C., Democritus developed the theory that objects were made up of atoms. In the 21st century, Yale applied physics professor Michel Devoret hopes do something as novel — take quantum mechanics and build computers with it.

In a lecture Tuesday that included not one mathematical formula, Devoret described the world of applied quantum physics in the first talk of a multi-lecture series celebrating the 150th anniversary of engineering at Yale. In his talk, titled “The Quantum Computer: Miracle or Mirage,” Devoret explained how quantum mechanics can be used to perform previously unworkable calculations through a new quantum-based computer.

“You always wonder [about the turnout] with a talk as technical as this,” Dean of the Faculty of Engineering Paul Fleury said. “I was afraid that the subject might scare people off.”

But to Fleury’s delight, practically not one of the seats in Davies Auditorium was left empty.

Donald Nguyen ’04 happened to be walking by the auditorium when he noticed signs for the seminar and decided to listen in. The computer science major ended up staying for the entire lecture.

“I thought he made quantum computing very accessible,” Nguyen said.

Devoret and his contemporaries are leading a new breed of physicists in the field of quantum physics. No longer is quantum theory just a tool for explaining observed phenomenon. It is being applied to open up a completely new area of discovery.

“I don’t give out Nobel Prizes, but I think this could be [Nobel quality work],” Fleury said.

Fleury added that Devoret has won several prestigious international awards such as the Ampere Prize of the French Academy of Science and the Descartes-Huygens Prize of the Royal Academy of Science of the Netherlands.

In the hourlong seminar, Devoret compared a classical “flip-flop” switch of a standard computer to its quantum equivalent, a qubit. The qubit — the elementary quantum information unit — is the formative basis on which quantum computer models are now being developed.

The qubit’s main advantage is that it deals with an almost infinite number of energy states. This allows quantum computers to process more information at once.

“This is not simply making things faster,” Devoret said. “It is changing the class of the problem, taking things that were impossible and making them tractable.”

But one drawback to the quantum qubit is that once a readout is taken from a quantum device, the structure of the qubits producing the readout is destroyed. As a result, when and how to take readings from such systems are critical questions.

Discussing the potential application of his research has been a tough point for Devoret — he said it remains to be seen how the power of this technology may be harnessed in the future.

But there are already potential applications of Devoret’s work. Detection of life on other planets is aided by quantum devices, since they are much more sensitive to weak signals from outer space than current technology.

Devoret also mentioned quantum cryptography as another application for his research, as the massive computing ability of a quantum computer could potentially make encryption useless.

Devoret arrived at Yale within the past month after working at a government laboratory in Saclay, a suburb of Paris. Fleury said Devoret’s arrival “optimizes the rejuvenation” of Yale’s Faculty of Engineering in the last 10 years.

“There is already a nucleus of world-class faculty members in both physics and applied physics, and his joining us puts us at the top of the map,” Fleury said.