Never say never - or for that matter, "insoluble." That's the philosophy of Professor of Physics Leon Cooper, whose theory of superconductivity - once thought to be an insoluble, or impossible to solve, phenomenon - revolutionized the world of physics and earned him the Nobel Prize in Physics in 1972.
Cooper, the "C" in the renowned BCS theory of superconductivity, was the keynote speaker in a scientific symposium held Thursday and today to honor the 50th anniversary of his theory's publication. As part of the symposium, six eminent physicists with five Nobel prizes - including three of the last six given in the field - assembled Thursday for a discussion panel and two lectures in Salomon 101.
Though the other Nobel prizewinners do not research superconductivity specifically, the entire two-day symposium is dedicated to BCS theory, which Vesna Mitrovic, assistant professor of physics and a co-organizer of the event, called "the most beautiful and influential theory of the 20th century" - even more so than Einstein's famous theory of relativity.
Superconductivity is a physical phenomenon where current flows through a supercooled metal - or superconductor - without any loss in energy. Normal metals partially impede the flow of electric current and cause some energy to be released as heat. But superconductors, which must be cooled hundreds of degrees below freezing in order to exhibit their special characteristics, allow current to flow unimpeded.
Dutch physicist Heike Kamerlingh Onnes first observed superconductivity in mercury in 1911, but explaining the phenomenon stumped scientists. Even Albert Einstein couldn't establish a theory of superconductivity when he tried in 1922.
"What we had that Einstein didn't was a quantum theory of metals," Cooper said.
Using quantum theory, Cooper came to the conclusion that electrons, which usually repel each other, pair up in a superconducting metal and exhibit a weak attractive force. Now called Cooper pairs, these pairs formed the basis for the BCS theory Cooper developed with colleagues John Bardeen and John Schrieffer.
BCS has had significant implications. Superconductors have been used to build fMRI technology - now a mainstay of medical treatment - and maglev trains, which use superconductors to levitate over magnetic tracks while traveling at over 350 mph.
"It is as though we set out to build a car and on the way invented the wheel," Cooper said of the theory.
In his keynote speech yesterday, Cooper emphasized the need for a shift in attitude toward problems considered insoluble.
"Could the medieval astronomer have imagined that all of the complexities of planetary motion would follow as a consequence of two postulates?" he said, referring to Isaac Newton's laws. "What seems impossible one day becomes ordinary the next."
Cooper, who also has expertise in neuroscience, said the greatest problem facing science is explaining how mental states arise.
" 'All of our sorrow is real, but the atoms of which we are made are indifferent,' " Cooper said, quoting philosopher George Santayana. "How do we construct real sorrow from hypothetically indifferent atoms?"
Cooper's lecture followed a speech on the applications of superconductors by Alexis Malozemoff, a physicist and both chief technical officer and executive vice president of superconductor supplier American Superconductor. Malozemoff spoke about integrating superconductors into the electric power grid, which he said is in dire need of reform.
Investment in energy transmission has declined despite continuous increases in energy consumption, he said, and superconductors - with their higher electric load and lossless transmission of energy - may be the best solution. Malozemoff pointed to high temperature superconductors, which can function at a balmy 135 K or -217 degrees (low temperature superconductors must be cooled to 4 K or -452 degrees) as the future of superconductivity's applications.
Malozemoff held a thin material in his hand, which he called a "generation-two" HTS wire. The "generation two" superconducting cables can support over 150 times the current of a standard copper cable at a fraction of the size. This technology could lead to a decreased load on urban energy transmission infrastructure, which Malozemoff said is currently "so dense that there is no room for more." Because superconductors can carry current without costs in energy, they are ideal - and have already been used - for energy storage, Malozemoff said.
In between the two lectures, Malozemoff, Cooper and four other Nobel prize-winning physicists fielded questions on a discussion panel.
Frank Wilczek, who won a Nobel in 2004 for his work with tiny particles called quarks, praised BCS theory and its applications in fields considered far removed from superconductivity.
"In our theories of elementary particles, we've postulated that empty space as we see it is actually one big cosmic superconductor," he said.
Anthony Leggett, winner of the 2003 Nobel for work in superfluidity, was asked if a room-temperature superconductor might ever be found.
"I personally am not very optimistic about that," he said. "Nature doesn't make many materials. She's not very creative that way."
The discussion concluded after one student asked the prominent physicists about their advice to aspiring scientists.
"Find a question that really intrigues you, and follow it," Leggett said. "The areas of physics that can be most exciting in the near future will be those that, in some way or another, combine physics with other disciplines."
"Physics is very hard work," Cooper said. "The trick is to make very hard work fun and love what you are doing."
The symposium will continue today within the Department of Physics, but the remaining programs are not intended for public attendance.
