February 7, 2011

by Benjamin White 

A packed house of Ohio University students and Athens residents listened intently in the normally-bustling Front Room coffee house at Ohio University's Baker Center as NQPI physics professor Eric Stinaff lectured on the future of quantum computing.

The future of computers, he said, will use an “entirely new paradigm... something that fundamentally depends on the laws of quantum mechanics to perform its computation.”

Humanity's current technology, including cell phones, computers and video games, could have been easily explained to traditional physicists like Isaac Newton, Dr. Stinaff explained, because all electronics function in accordance with the traditional laws of physics and understandable phenomena like magnetism. New models of quantum computing operate on such a small scale that they must fundamentally utilize quantum physics, a murky and relatively recently-discovered world of strange physical laws within every molecule.

Dr. Stinaff explained that historically, it has taken roughly a century to utilize new discoveries in science for the engineering of new products. For instance, electricity and magnetism were first studied and written about in the 1700s, but the first electrical engineering department in England did not appear until 1885. The laws of quantum mechanics, while not always fully understood, have been studied for roughly 100 years, and the first quantum engineering program has already been started in Japan.

Quantum mechanics may sound strange and abstract to the average person, but these physical laws apply to every atom of material in the universe. Dr. Stinaff focused on two quantum properties of matter, superposition and entanglement, that could be used to create a faster, smaller computer.

Superposition concerns a property of subatomic particles called spin. Spin is angular momentum, more easily described as a magnetic force that can only be found in two states, like a penny lying face-up or face-down. The tricky part, scientists have found, is that before spin is measured as up or down, the particle seems as if it exists in both states at once, like a penny balanced on its side. The state of a particle that is both spin-up and spin-down is called superposition.

Computer engineers could use particles in superposition by using the electron's spin as the bit in binary code. Current computers simply recognize whether an electron is in a slot to determine whether there is a “1” or “0” in the binary code. Since particles in superposition can be both spin-up and spin-down at once, each particle, in theory, would be able to show two states: “1” and “0” at the same time or interchangeably. This would make computers exponentially smaller and more efficient.

Another quantum property that could be used in information processing is entanglement, such a strange phenomenon that Einstein called it “spooky action at a distance.” When Dr. Stinaff asked his colleagues observing the lecture if they understood entanglement, he only drew laughs.

“Quantum mechanics is kind of like a bad trip,” Dr. Stinaff explained. “It's kind of weird.”

When scientists entangle two particles, a process too complex for Dr. Stinaff to explain, they form a unique bond. When the spin of one particle is measured as spin-up, the other will always be measured as spin-down, no matter where they are in relation to each other. If two particles are entangled in New York City and one is flown to Los Angeles, as soon as the one in Los Angeles is measured, the one in New York City will measure the opposite.

While no scientist claims to understand the phenomenon of entanglement, this discovery could be of some use for computer engineers and cryptologists. Quantum entanglement is already being used for ultra-secure communication by the military and at least one private company.

Though some supercomputers currently rely on quantum mechanics, a complete overhaul of computers remains doubtful. More likely is a shift of certain components of computers like video cards or hard drives to incorporate quantum technology, Dr. Stinaff said.

Science Cafés at the Front Room Coffee House showcase Ohio University scientists' work and offer a venue for interested students and members of the community to converse with the brightest minds at OU. All lectures start at 5 p.m. Every other Wednesday. For more information visit www.ohio.edu/sigmaxi/sciencecafe.