Invisible touch? Yeah, by combining computer vision and quantum sensing

Quantum Campus shares the latest in quantum science and technology from university campuses. We publish on Fridays and are always looking for news from researchers across the country. Want to see your work featured? Submit your ideas to the editor.

Dual-rail qubits

Quantum Circuits — a startup out of Rob Schoelkopf’s team at Yale — announced the first dual-rail qubits available via the cloud, opening the possibility of using fewer qubits with lower error rates in calculations. Processing units, based on transmons, use pairs of superconducting cavities to encode quantum bits with microwave frequency photons. The cavities have a dominant error channel leading to erasures on known qubits and thus have high-fidelity error detection, according to the company. 

Photon erasure is “90 percent or more" of the errors, Quantum Circuits’ Andrei Petrenko told Ars Technica. “So it’s a huge advantage that we have with photon loss over other errors. And that's actually what makes the error correction a lot more efficient: The fact that photon losses are by far the dominant error.”

Read the full Ars Technica article.

Quantum touch

A team from the Stevens Institute of Technology developed a system that combines single photon counting and computer vision algorithms to replicate a human sense of “touch.” Capturing the changes of back-scattered photons from different points on a surface into a single mode fiber and counting them using a single photon detector, they were able to determine the difference in the roughness of surfaces within four microns, which is comparable to the best industrial devices currently used. The results were published in Applied Optics.

The new method could have a variety of medical applications, like discerning among harmless skin conditions and potentially fatal melanomas, according to the Stevens Institute’s Yuping Huang.

“Tiny differences in mole roughness, too small to see with the human eye but measurable with our proposed quantum system, could differentiate between those conditions,” Huang said. “Quantum interactions provide a wealth of information, using AI to quickly understand and process it is the next logical step.”

Read the announcement from the Stevens Institute.

Mechanical qubit

Researchers at ETH Zurich built a qubit from a tiny physical machine. Made of a resonator of sapphire crystal with a dome of aluminum nitride that expands and contracts in response to an oscillating voltage, the mechanical qubit includes a superconducting qubit as a controller. Science magazine’s article on the qubit pointed out that “The new mechanical qubit is unlikely to run more mature competition off the field any time soon. Its fidelity — a measure of how well experimenters can set the state they desire — is just 60 percent, compared with greater than 99 percent for the best qubits.” But it also considered that the “mechanical qubit might serve as a supersensitive probe of forces, such as gravity, that don’t affect other qubits.”

Read the ETH Zurich team’s paper.

DOE Request for Information

The Department of Energy’s Quantum Computing User Program, which provides scientific researchers access to quantum computing resources, is gathering input on the current and upcoming availability of quantum computing resources; conventions for measuring, tracking, and forecasting quantum computing performance; and methods for engaging stakeholders in the quantum computing community.

DOE’s Request for Information will be open until January 10, 2025, through this survey.

Quickbits

• University of Maryland receives $2 million from the Air Force to develop approaches to quantum computing and sensing inspired by the brain

• Caltech team shows ultrafast all-optical coherence of molecular electron spins at room temperature

• IBM releases a new version of its Heron quantum chip; company claims calculation time for many tasks reduced by 50 times

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