Researchers with the Department of Energy at the Oak Ridge National Laboratory have demonstrated a new level of control over photons encoded with quantum information. Their research was published in Optica.
Joseph Lukens, Brian Williams, Nicholas Peters, and Pavel Lougovski, Research Scientists with ORNL's Quantum Information Science Group, performed distinct, independent operations, and on two qubits encoded on photons of different frequencies, a key capability in linear optical quantum computing. Qubits are the smallest unit of quantum information.
Quantum scientists working with frequency-encoded qubits in parallel, but that falls short for quantum computing.
"To achieve universal quantum computing, you need to be able to do different things on different qubits at the same time, and that's what we've done," Lougovski said.
According to Lougovski, the team's experimental system – one of the smallest quantum computers you can imagine This paper marks the first demonstration of our frequency-based approach to the universal quantum computing. "
"Lukens said," A lot of researchers are talking about quantum information processing with photons. "But no one had thought about sending multiple photons through the same fiber-optic strand, in the same space, and operating on them differently."
The team's quantum frequency processor allowed to manipulate the frequency of photons to bring about superposition.
Unlike datasets than today's supercomputers.
97 percent interference visibility – a measure of how alike two photons are compared with the 70 percent visibility rate returned in similar research. Their result indicated that the photons' quantum states were virtually identical.
The researchers also applied to the statistical method associated with machine learning to prove that the operations were done with very high fidelity and in a completely controlled fashion.
"We were able to extract more information about the experimental system using Bayesian inference than if we had used common statistical methods," Williams said.
"This work is the first time our team has process has returned to an actual quantum outcome."
Williams pointed out that their experimental setup provides stability and control. "When the photons are taking different paths in the equipment, they experience different phase changes, and that leads to instability," he said. "When you're traveling through the same device, in this case, the fiber-optic strand, you have better control."
Stability and control enable quantum operations that preserve information, reduce information processing time, and improve energy efficiency. The researchers compared their ongoing projects, begun in 2016, to building blocks that will link together to make large-scale quantum computing possible.
"Peters said." There are steps you can take before you go, "Peters said. "Our previous projects focused on developing fundamental capabilities and enable us to work in the full quantum domain with fully quantum input states."
Lukens said the team's results show that "we can control qubits" quantum states, change their correlations, and modify them using standard telecommunications technology in ways that are applicable to advancing quantum computing. "
"He can start connecting quantum devices to build the internet quantum, which is the next, exciting step."
Much the way that information is processed differently from supercomputer to supercomputer, reflecting different developers and workflow This is how they can work together on the internet.
This work is an extension of the team's previous demonstrations of quantum information processing capabilities on standard telecommunications technology. Moreover, they said, leveraging the existing fiber-optic network infrastructure for the quantum computing is practical: billions of dollars have been invested, and quantum information processing has become a novel use.
The researchers said this "full circle" aspect of their work is highly satisfying. "Lukens said." We started our research together with the use of standard telecommunications technology for quantum information processing, and we have found it.
Lukens, Williams, Peters, and Lougovski collaborated with Purdue University graduate student Hsuan-Hao Lu and his advisor Andrew Weiner. Research is supported by ORNL's Laboratory Directed Research and Development program.