Quantum Campus shares the latest in quantum science and technology. Read by more than 1,400 researchers, we publish on Fridays and are always looking for news from across the country. Want to see your work featured? Submit your ideas to the editor.

Photonic accelerators

A pair of startups published details of photonic computing devices in Nature this week.

Singapore’s Lightelligence announced a photonic accelerator that can be integrated with traditional electronics and run linear matrix multiply–accumulate functions. They demonstrated ultralow computation latency while solving computationally hard Ising problems. Lightspeed, based in the U.S., announced a photonic AI processor capable of running the ResNet3 deep learning model and the BERT neural network technique. The team claimed “near-electronic precision for many workloads.”

“This is an area which is kind of coming to the boil,” the University of Glasgow’s Robert Hadfield said, reflecting on the articles in coverage from New Scientist. “It’s close to a point where the industry may consider photonic processors as a viable alternative…And these are photonic chips which are fabricated in one of the world’s leading foundries, so it can be scaled up for mass production.”

Tuneable twisted moire crystals

A team from Harvard, Stanford, and Berkeley developed an optical sensor capable of measuring polarization and wavelength at the same time. Placing twisted moire photonic crystals on tiny vertical and rotary actuators, the researchers can change the twist angle and the spacing between layers. This on-chip setup allows them to precisely tune the device and use a reconstruction algorithm to “simultaneously resolve the spectrum and polarization state of a wide-band signal in the telecommunications range.”

These findings were published in Nature Photonics.

Magnons influence excitons

Physicists at City College of New York demonstrated quasiparticle-mediated interactions in correlated quantum materials. In their work, excitons in chromic sulfide bromide interacted via magnons — rather than by exchange interactions or phase-space filling — with the magnons influencing the excitons’ spin canting angle.

“One particularly exciting application enabled by this discovery is in the development of quantum transducers — devices that convert quantum signals from one frequency to another, such as from microwave to optical. These are key components for building quantum computers and enabling the quantum internet,” postdoc Pratap Chandra Adak said in an announcement from CCNY.

This study appeared in Nature Materials.

QBI Stage A

DARPA announced 15 companies that will be part of “Stage A” of the agency’s Quantum Benchmarking Initiative.

“[N]ow the real work begins. Stage A is a six-month sprint in which they’ll provide comprehensive technical details of their concepts to show that they hold water and could plausibly lead to a transformative, fault-tolerant quantum computer in under 10 years," said Joe Altepeter, DARPA QBI program manager.

Three additional, unnamed are still negotiating agreements with DARPA. The companies chosen were:

• Alice & Bob (superconducting cat qubits)

• Atlantic Quantum (fluxonium qubits with co-located cryogenic controls)

• Atom Computing (scalable arrays of neutral atoms)

• Diraq (silicon CMOS spin qubits)

• Hewlett Packard Enterprise (superconducting qubits with advanced fabrication)

• IBM (quantum computing with modular superconducting processors)

• IonQ (trapped-ion quantum computing)

• Nord Quantique (superconducting qubits with bosonic error correction)

• Oxford Ionics (trapped-ions)

• Photonic Inc. (optically-linked silicon spin qubits)

• Quantinuum (trapped-ion quantum charged coupled device (QCCD) architecture)

• Quantum Motion (MOS-based silicon spin qubits)

• Rigetti Computing (superconducting tunable transmon qubits)

• Silicon Quantum Computing Pty. Ltd. (precision atom qubits in silicon)

• Xanadu (photonic quantum computing)

Quickbits

• JQI and APS seek applications for “The Schrödinger Sessions”

• University of Maryland announces Applied Research Laboratory for Intelligence and Security

• Tunable Polariton Rabi Oscillation in Phase-Changing Perovskite Microcavities (Advanced Science)

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