A new light on one of modern physics’ greatest mysteries

Institut national de la recherche scientifique - INRS

MONTREAL, QC, October 20, 2026 - Transmitting electricity without losing any energy may sound impossible, yet this is precisely the promise of superconductivity. For nearly 40 years, scientists have been working to understand materials that exhibit this remarkable property at relatively high temperatures. Unlocking their secrets could one day help make power grids more efficient, enhance medical technologies, and support the development of quantum computing.

Among the most promising of these materials are cuprates, a family of copper-based compounds discovered in 1986. The breakthrough was so significant that its discoverers, Bednorz and Müller, were awarded the Nobel Prize in Physics the following year. Despite decades of research, however, the mechanisms that allow cuprates to become superconducting remain poorly understood.

At the heart of this puzzle lies the pseudogap, a mysterious quantum state whose exact role continues to spark debate. Some scientists believe it helps superconductivity emerge, while others see it as a competing phenomenon.

That question is precisely what a team led by INRS Professor Fabio Boschini, Canada Research Chair in Quantum Materials’ Dynamics and recipient of an Alfred P. Sloan Research Fellowship, set out to investigate. In a study published in Nature Physics, the researchers provide new evidence suggesting that the pseudogap and superconductivity compete with one another rather than work together.

“The pseudogap is one of the greatest mysteries in condensed-matter physics. Understanding how it interacts with superconductivity is essential if we want to explain why these materials can carry electricity without energy loss at unusually high temperatures,” says Fabio Boschini, Professor at INRS and a specialist in ultrafast spectroscopy of quantum condensed matter.

The research was carried out at the INRS Énergie Matériaux Télécommunications Research Centre, using world-class research infrastructure, including the time- and angle-resolved photoemission spectroscopy (TR-ARPES) endstation at the Advanced Laser Light Source (ALLS). The INRS team also collaborated with several international partners, including the Center for Computational Quantum Physics at the Flatiron Institute in New York.

“The pseudogap and superconducting states in cuprates are among the most complex phenomena to reproduce theoretically. Our study reveals that they compete with one another and provides new insight into their behavior when both are excited simultaneously,” said Olivier Gingras, Associate Research Scientist at the Flatiron Institute's Center for Computational Quantum Physics.

Revealing a quantum rivalry with light

To better understand the role of the pseudogap, the researchers temporarily suppressed superconductivity using a pulse of light and then observed how the material responded in real time.

The experiment allowed the team to observe, for the first time, a light-induced transient pseudogap and to access electronic states that had previously remained hidden from conventional techniques.

“Thanks to the unique capabilities of the TR-ARPES system at the ALLS laboratory at INRS, we were able to directly observe what happens when superconductivity temporarily disappears and then re-emerges. It is a bit like uncovering missing frames from a film that scientists have been trying to piece together for decades,” says Dario Armanno, a PhD student at INRS and first author of the study.

The results show that when superconductivity is suppressed, the pseudogap emerges in its place. As superconductivity returns, the pseudogap fades away.

These findings suggest that the two phenomena compete rather than cooperate, challenging the long-standing hypothesis that the pseudogap acts as a precursor to superconductivity.

“This research is essential to advancing the quantum technologies of the future. It contributes to the training of highly qualified personnel in a field that is critical to Canada’s technological sovereignty and to the implementation of its National Quantum Strategy,” says François Légaré, Director of the INRS Énergie Matériaux Télécommunications Research Centre.

While this is fundamental research, the discovery represents an important step forward in understanding a phenomenon that could play a key role in the development of next-generation superconductors and, ultimately, more energy-efficient technologies.