Quantum: The Next Generation in Computing

While computers are getting progressively smaller and more powerful, the underlying principles – encoding information in long strings of ones and zeroes – have not changed markedly in 50 years.But that could soon change.

Scientists at Duke University and elsewhere are making advances in a new type of computing that may have seemed purely theoretical, but could now be possible within our lifetimes. Literally, this new generation of computers will be a quantum leap forward in technology.

The workings of conventional computers are driven by the laws of classical physics, where the millions of ones and zeroes are maintained on an actual physical entity, whether it be a chip or a hard drive, and respond to “yes” or “no” questions. However, chips can only get so small before they become the size of an atom, at which time another type of physics, known as quantum physics, comes into play.

In this sub-atomic quantum world, governed by its own often counter-intuitive laws, great potential lurks. But this potential can only be realized when scientists figure out how to create and capture the fleeting events at the atomic scale that are at the core of the computer’s power. When brought under control, these properties offer the possibility of unimaginable computing power.

Jungsang Kim

For example, explains Jungsang Kim, Nortel Networks assistant professor of electrical and computer engineering at Duke’s Pratt School of Engineering, future quantum computers could easily crack cryptosystems widely used for secure communication today – whether to bank accounts or military installations – in the blink of an eye. Current security measures rely on the impossibility of conventional computers to calculate all the computational possibilities in a reasonable amount of time.

“In many ways, we stand at the same place we did in the 1950s,” said Kim. “The physicists knew how to make transistors, but integration was still lacking until the integrated circuits technology was invented. Just like then, the physicists have shown that quantum computing is possible, it is now up to the engineering community to create and integrate technologies to make it happen.”

Not surprisingly, the federal government is keen to find out if quantum computing is a pipe dream or the real deal. Recently, a team of engineers from Duke, Georgia Tech and Massachusetts Institute of Technology received a multi-year grant from the Intelligence Advanced Research Projects Activity (ARPA) and the Army Research Office to work on specific challenges facing the development of quantum computers.

At the heart of a quantum computer are quantum bits of information trapped in a single atomic ion known as a qubit.

“We manipulate these qubits in physical systems using light in the form of lasers,” Kim explained. “Lasers control the internal atomic states, as well as measure scattered light to read out the quantum registers (the quantum analogue of the processor register).”

The main focus of the team’s effort (Georgia Tech, Duke and MIT) is to create technologies that integrate all of the components necessary to create a complex quantum information processor. This includes ion traps fabricated on a chip, controllers to move ions around on the chip, and optical components needed to control and measure the ion qubits.

Specifically, Duke will be developing optical components that can be integrated into the rest of the system to provide advanced optical capabilities.

“We are working on microfabricated optical components like small mirrors and micro-scale optical cavities to enhance the detection and communication of the qubits,” Kim said. “We will be integrating these small optical components into microfabricated ion traps currently under development at Georgia Tech. We also have a separate program to utilize micromachined mirrors to control the laser beams that control the quantum registers.”