August 13, 2015

Quantum computing advance locates neutral atoms

"We are studying neutral atom qubits because it is clear that you can have thousands in an
apparatus," said Weiss. "They don't take up much space and they don't interact with each other
unless we want them to." Image: © iStock Photo monsitj

(August 12, 2015)  For any computer, being able to manipulate information is essential, but for quantum computing, singling out one data location without influencing any of the surrounding locations is difficult. Now, a team of Penn State physicists has a method for addressing individual neutral atoms without changing surrounding atoms.

"There are a set of things that we have to have to do quantum computing," said David S. Weiss, professor of physics. "We are trying to step down that list and meet the various criteria. Addressability is one step."

Quantum computers are constructed and operate in completely different ways from the conventional digital computers used today. While conventional computers store information in bits, 1's and 0's, quantum computers store information in qubits. Because of a strange aspect of quantum mechanics called superposition, a qubit can be in both its 0 and 1 state at the same time. The methods of encoding information onto neutral atoms, ions or Josephson junctions -- electronic devices used in precise measurement, to create quantum computers -- are currently the subject of much research. Along with superposition, quantum computers will also take advantage of the quantum mechanical phenomena of entanglement, which can create a mutually dependent group of qubits that must be considered as a whole rather than individually.

"Quantum computers can solve some problems that classical computers can't," said Weiss. "But they are unlikely to replace your laptop."

According to the researchers, one area where quantum computers will be valuable is in factoring very large numbers created by multiplying prime numbers, an approach used in creating difficult-to-break security codes.

Weiss and his graduate students Yang Wang and Aishwarya Kumar, looked at using neutral atoms for quantum computing and investigated ways to individually locate and address an atom to store and retrieve information. They reported their results in a recent issue of Physical Review Letters.

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