This is a preview issue of Quantum Campus, which 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.

Hybrid quantum neural networks

Researchers at Cleveland Clinic’s Center for Computational Life Sciences built a hybrid quantum neural network that was able to predict proton affinity more accurately than classical computing. In it, a parameterized quantum circuit serves as a feature encoder, embedding input features into a quantum-enhanced representation that is subsequently processed by a classical neural network. The calculations were run on an IBM Quantum System One.

More efficient ways to estimate this affinity allow for the rapid identification of the most favorable protonation site in complex organic molecules with multiple proton binding sites — someday translating into quicker drug development and other chemistry applications.

“This project was one of our first experiences with [quantum machine learning],” Cleveland Clinic’s Kenneth Merz said in an announcement. “Machine learning has already proven to be useful in chemistry because of its ability to correlate chemical structures with their physical-chemical properties and predict reaction outcomes. With the power of quantum computing, it can surpass even the most advanced supercomputer with its compute power.”

The study was published in ACS’s Journal of Chemical Theory and Computation.

Entanglement-preserving optical filter

USC engineers demonstrated the first optical filter capable of isolating and preserving quantum entanglement. Using anti-parity-time symmetry, it opens the door to compact, high-performance entanglement systems that can be integrated into quantum photonic circuits, enabling more reliable quantum computing architectures and communication networks.

“This filter doesn’t just preserve entanglement — it distills it from a noisy mixed quantum state. It leaves the quantum core intact while shedding everything else,” USC graduate student Mahmoud A. Selim said in an announcement.

The work was published in Science.

Maximally entangled superimpositions

University of Toronto engineers discovered hidden multi-dimensional side channels in existing quantum communication protocols. The team found that hidden multidimensional modulation is created by source devices, creating these side channels and security loopholes.

These finding were published in Physical Review Letters. 

Pseudorandomness

Quanta magazine published a review of the concept of pseudorandomness and its promise in quantum cryptography. Focusing on a pre-print by researchers from the Simons Institute, Berkeley, Google, Caltech, and MIT, it discusses the possibility of building pseudorandom quantum circuits and the ways those circuits would expand a variety of potential quantum applications.

Quickbits

• More skepticism of D-Wave’s claims of quantum supremacy (IEEE Spectrum)

• High-performance fault-tolerant quantum computing with many-hypercube codes (Science Advances)

• Barren plateaus in variational quantum computing (Nature Reviews Physics)

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