The power of computers can be limited by their own hardware.
These limits could be the inability to keep track of large amounts of data or perform complicated calculations.
On the smallest scale, it takes the work of physicists studying atoms to push those limits.
Phil Richerme, assistant professor of physics at IU, studies the interactions between atoms that can be used to build powerful computers known as quantum computers.
Specifically, Richerme studies atomic interactions in superconductors.
Superconductors are materials that easily conduct electricity and can be used in building quantum computers.
In contrast to a classical computer, in which data is stored in either zeros or ones, quantum computers use data that have many values simultaneously, Richerme said.
“Quantum supremacy is the idea of a quantum algorithm or quantum device that allows you to solve a problem more quickly than a classical computer would,” Richerme said.
There are a lot of companies, like Google and IBM, investing money into building hardware that uses quantum computing because they can use it to search large amounts of data, Richerme said.
Quantum cryptography uses these properties to create secure forms of information, such as passwords, Richerme said.
“Each of the individual atoms in a superconductor works like a quantum particle,” Richerme said.
These quantum particles allow quantum computers to solve problems a classical computer couldn’t, Richerme said.
“There are many hundreds or thousands of these particles that can interact,” Richerme said. “What I want to build is a programmable quantum device that can solve these kinds of problems.”
To get to the heart of the physics behind quantum computers, Richerme is conducting an experiment to study physical quantum systems in his lab.
The experiment uses lasers to study atomic interactions, Richerme said.
“They act like individual quantum particles, and, using lasers, we make those individual quantum particles interact with each other,” Richerme said.
Anton Frommelt, a research assistant in Richerme’s lab, said he has worked with three different laser systems to study atomic interactions.
“Everything is about planning and engineering to get the experiment running,” Frommelt said.
Along with studying the lasers using lenses, Frommelt also uses radio signals to determine properties of the atoms.
“What got quantum computing started was Shor’s algorithm, which demonstrated that using a quantum computer you can factor large numbers in a polynomial amount of time rather than an exponential amount of time,” Richerme said.
This means quantum computers can perform difficult mathematical tasks much more quickly than classical computers can.
“There’s no known impediment to making quantum devices. It’s a question of engineering to make it happen,” Richerme said.
While all proposed quantum algorithms have been demonstrated in experiments, Richerme said their potential hasn’t been fully realized.
“It’s about making the system large enough to realize quantum supremacy,” Richerme said.