New Atom and Photon 'Switch' May Herald Breakthrough for Quantum Computers

Quantum computing could be closer than ever. Scientists have used a laser to place individual rubidium atoms near the surface of a lattice of light, which means that there's a new method for connecting particles which, in turn, could help develop quantum computing systems.

Quantum computing is computing through the art of physics. It could enable the rapid performance of calculations by taking advantage of the distinctive quantum-level properties of particles. Some particles can actually be in a condition of superposition, which means they appear to exist in two places at the same time. These particles, called qubits, could theoretically contain more information than particles at classical scales and could allow for faster computing.

"This is a major advance of this system," said Vladan Vuletic, one of the researchers, in a news release. "We have demonstrated basically an atom can switch the phase of a photon. And the photon can switch the phase of an atom."

So what does that mean exactly? Photons can have two polarization states, and interaction with the atom can change the photon from one state to another. By that same token, interaction with the photon can change an atom's energy level from a "ground" state to an "excited" state. This means that atom-photon coupling can essentially serve as a quantum switch.

"In some sense, it was a big surprise how simple this solution was compared to the different techniques you might envision of getting atoms there," said Vuletic. They developed a "hybrid quantum system" where individual atoms were coupled to microscopic fabricated devices and where they could control the atoms and photons in productive ways.

"For me what is still amazing, after working in this for 20 years, is that we can hold onto a single atom, we can see it, we can move it around, we can prepare quantum superpositions of atoms, we can detect them one by one," said Vuletic in a news release.

The findings reveal a new breakthrough for quantum computing systems. This switch could potentially be a component in such systems in the future.

The findings are published in the journal Nature.