A team of researchers at the University of Ottawa and its Nexus for Quantum Technologies Institute, in collaboration with researchers from Federico II University in Italy, has developed a programmable quantum simulator that shapes a beam of light to replicate how particles move through complex materials, avoiding the need for ever-larger electronic hardware.
Rather than wiring together intricate circuits, the researchers carefully sculpt the spatial pattern and polarization, two internal degrees of freedom of photons so that they evolve the same way electrons would inside a crystal. Three programmable optical screens called spatial light modulators do the heavy lifting, and a simple software update is all it takes to reconfigure the entire experiment for a new simulation.
"We program the structure of light the way a musician tunes an instrument," says Ebrahim Karimi, Full Professor in uOttawa's Department of Physics. "Each configuration lets photons walk through a different virtual material, and we can switch between hundreds of them without touching the optics."
Light does the heavy lifting
The team validated the platform with both classical laser light and individual photons, running more than 300 distinct quantum processes and spreading a single input beam across thousands of output channels. In one set of experiments, the simulator reproduced the telltale signatures of topological materials, exotic phases of matter whose internal geometry protects electrons from disturbances, a phenomenon at the heart of next-generation electronics.
"Topology is a hot topic in condensed-matter physics, but measuring its effects directly is notoriously hard," says Dr Alessio D’Errico, senior research associate at Prof. Karimi’s team. "Our optical platform lets us watch those effects unfold in real time, right on a camera."
The system's reach extends well beyond flat grids. By reprogramming the optical patterns, the same setup simulates particle motion on closed loops, cylinders, and doughnut-shaped surfaces, geometries that capture features of advanced quantum materials which have rarely, if ever, been reproduced in a purely photonic experiment.
"A torus or a cylinder might sound abstract, but these shapes encode real physics," explains Dr D’Errico. "Being able to explore them all on a single, reconfigurable table-top setup is a genuine step forward for quantum simulation."
“We program the structure of light the way a musician tunes an instrument”
Ebrahim Karimi
— Full Professor in uOttawa's Department of Physics
A new kind of quantum laboratory
Because the information lives in light, every stage of the quantum evolution can be photographed directly, giving researchers an unusually clear view of dynamics that are typically buried deep inside solid-state devices. The work opens a path toward using compact photonic platforms to study quantum transport, probe topological phenomena, and prototype building blocks for future quantum technologies.
"We've essentially turned light into a controllable laboratory for quantum matter studies," concludes Professor Karimi. "Complex dynamics can be designed, watched, and understood with a clarity that simply wasn't available before."
The findings appear in two 2026 publications: “Compact and programmable large-scale optical processor in free space” published in Nature’s Light: Science & Applications. Authorship: Maria Gorizia Ammendola, Nazanin Dehghan, Lukas Scarfe, Alessio D’Errico, Francesco Di Colandrea, Ebrahim Karimi & Filippo Cardano.
And “Programmable photonic quantum walks on lattices with cyclic, toroidal, and cylindrical topology” published in Advanced Photonics. Authorship: Alessio D'Errico, Nazanin Dehghan, Maria Gorizia Ammendola, Lukas Scarfe, Roohollah Ghobadi, Francesco Di Colandrea, Filippo Cardano, Ebrahim Karimi.
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