A University at Buffalo-led study published January 21, 2026, reveals that light and matter don’t always rapidly reach thermal equilibrium—a finding with significant implications for scaling up quantum computing. Researchers found that, under specific conditions, photons and atoms can maintain different temperatures even while interacting for extended periods, defying expectations about energy exchange. This discovery is crucial because thermal equilibrium typically erases the quantum properties needed for computation. “Thermal equilibrium alters quantum properties, effectively erasing the very information those properties represent in a quantum computer,” says Jamir Marino, PhD, assistant professor of physics at UB. This delayed thermalization offers a vital “temporal window” to preserve and process quantum information in emerging neutral-atom quantum computers, which utilize light and atoms to perform calculations.
Photons and Atoms Bypass Rapid Thermalization
Conventional wisdom dictates that when light and matter mingle, energy exchange swiftly leads to thermal equilibrium – a uniform temperature masking the delicate quantum properties crucial for advanced computation. However, a new theoretical study led by the University at Buffalo challenges this assumption, revealing scenarios where photons and atoms can maintain distinct temperatures even during prolonged interaction. Published in Physical Review Letters, the research offers a promising pathway for scaling up neutral-atom quantum computing. The team’s simulations focused on a neutral-atom array contained within an optical cavity, a setup designed to force repeated light-matter interactions.
Researchers discovered that following an initial energy exchange, the system doesn’t necessarily rush towards a single temperature; instead, atoms and photons can enter a “prethermal state” where energy sharing slows dramatically. “The modeling demonstrates it may indeed be feasible to use light to link larger neutral-atom arrays without washing away the quantum information,” explains co-author Hossein Hosseinabadi, PhD, a future distinguished postdoctoral scholar at the Max Planck Institute. Intriguingly, the simulations revealed instances of “opposite” temperatures emerging—atoms settling at negative temperatures while photons remain positive—a phenomenon sustained for potentially crucial milliseconds. The implications for quantum computing are significant.
Neutral-atom qubits, which utilize single atoms as information units, rely on light beams for control and connection. Aleksandr Mikheev, PhD, the study’s first author, warns that prolonged interaction could “mean the light essentially destroys the very quantum information it was meant to carry.” However, the research suggests that, with careful design, the emitted light could even facilitate connections between arrays, creating a self-sustaining system. “This is crucial because you wouldn’t have to continuously intervene. Once the system is set up, it can naturally remain out of thermal equilibrium for a long time,” Marino concludes.
Optical Cavities Preserve Non-Equilibrium States
This preservation of non-equilibrium states hinges on confining the light within an optical cavity, formed by a pair of mirrors that force repeated interaction with the atoms. In some scenarios, the atoms even reach “negative temperatures” while photons remain at positive temperatures—a counterintuitive outcome. This ‘prethermal’ state, though fleeting on a human timescale, offers a crucial window for quantum information processing. Current neutral-atom systems utilize brief laser pulses, minimizing thermalization risk, but future scalability demands linking multiple atom arrays with persistent light – a scenario previously feared to induce rapid thermal equilibrium.
Thermal equilibrium alters quantum properties, effectively erasing the very information those properties represent in a quantum computer.
Jamir Marino, PhD
Rydberg Atom Arrays Enable Extended Quantum Behavior
A new theoretical understanding of light-matter interactions promises to extend the operational window for a promising quantum computing architecture. This research addresses a key challenge in scaling up neutral-atom qubit systems, which leverage individual atoms—often alkali metals excited into Rydberg states—as information units. While these systems boast simpler hardware compared to superconducting qubits, concerns have lingered regarding the potential for light-induced thermalization, which destroys delicate quantum states. This “prethermal state”—though fleeting on everyday timescales—offers a temporal buffer to preserve quantum information. Crucially, the modeling suggests a pathway towards linking multiple Rydberg atom arrays via light without immediately succumbing to thermalization.
