College of William and Mary

12/18/2025 | Press release | Distributed by Public on 12/18/2025 10:51

A quantum world

A quantum world

Over 100 years since the genesis of quantum physics, William & Mary scientists continue to push the boundaries of what is known.

On Dec. 14, 1900 German physicist Max Planck proposed the first quantum theory - that energy is transferred in discrete packets or quanta. This opened the floodgates for a scientific revolution that would transform the world - in ways good and bad. (Photo from iStock)

Between 1900 and 1925, the world of physics was shaken to its core.

Scientists like Max Planck, Albert Einstein and Niels Bohr proposed bold new theories and mathematical formulas, showing that atomic and subatomic particles do not adhere to the principles of classical physics. The field of quantum physics was born, describing how the smallest units of matter and energy behave.

Quantum physics has been a central focus of the William & Mary Physics Department since the late 1950s. Faculty work on the cutting edge: from studying the fundamental nature of the universe to designing hyper-sensitive sensors, next-generation computers and novel quantum materials.

The department also closely collaborates with two of the nation's premier U.S. Department of Energy research facilities: the Thomas Jefferson National Accelerator Facility in Newport News, Virginia, which is a world leader in nuclear physics, and the Fermi National Accelerator Laboratory in Batavia, Illinois, which is America's premier laboratory for particle physics.

To celebrate 2025 as the International Year of Quantum Science and Technology, several William & Mary physicists described their research and how they innovate in a field that continues to reshape the world.

Cracking quantum computing

William & Mary Physics Professor Enrico Rossi is tackling one of the fundamental challenges of quantum computing. (Photo by Stephen Salpukas)

Imagine someone trying to solve a maze: They test one path after another until they finally find their way through. This is similar to how classical supercomputers tackle certain problems. But quantum computers, by using a special property called superposition, can explore many possible paths in a coordinated way at once - potentially leading to much faster solutions for specific types of problems. While quantum computers hold incredible potential, they are still too error-prone to be broadly useful.

One challenge is that qubits, the basic units of quantum information, are fragile and easily perturbed by vibrations, temperature fluctuations and electromagnetic noise, leading to computing errors. Traditionally these errors have been combatted by complex error-correcting systems, but some scientists, including William & Mary Physics Professor Enrico Rossi, are approaching the decoherence problem from another dimension.

Rossi is a theoretical physicist who, for over two decades, has been studying the theory of topological superconductors. These materials can be created by layering a conventional superconductor and a semiconductor and could hold the key to nearly error-free qubits. Instead of encoding the quantum information in one specific area, topological superconductors split the information, in this case an electron's quantum state, across space. This prevents a perturbation in one location from collapsing the quantum system and causing errors.

As theoreticians, Rossi and his W&M students and postdocs have been developing the guidelines to develop, test and finetune topological superconductors. Their work contributed to Microsoft's groundbreaking February 2025 announcement that they had realized the first quantum chip based on this technology. If this claim is validated, it would represent a promising step forward in a long trek toward success. A working quantum computer based on topological superconductors will likely require over a million qubits.

"The Holy Grail of quantum computing is a machine capable of factoring large numbers. A goal that might be within closer reach is to use quantum computers to train artificial intelligence systems to solve previously unsolvable problems in chemistry, biology, physics and beyond."

Enrico Rossi, Physics Professor, William & Mary

To investigate other approaches to designing topological superconductors, Rossi and collaborators received a $1.7 million grant from the U.S. Department of Energy's newly established Basic Energy Sciences program in quantum information science. As principal investigator on this grant, Rossi is working with New York University and Sandia National Laboratories.

Pushing beyond the quantum limits of light

William & Mary Physics Professor Irina Novikova (left) is bending the rules of quantum physics to create hyper-sensitive sensors. Here she is pictured in the lab with students Kalea Wen '26 and Nicolas DeStefano M.S. '21 (Photo by Eugeniy Mikhailov)

William & Mary Physics Professor Irina Novikova is helping advance what scientists call the "Second Quantum Revolution" - actively manipulating quantum states of light and matter to build devices that outperform anything classical physics would allow.

In Novikova's Quantum Optics Laboratory, she and her students explore how to control the quantum properties of light. One major application is improving the sensitivity of magnetometers, devices that detect extremely small magnetic fields for uses ranging from medical diagnostics to national security.

"How can you create new quantum states of light to break the accuracy limit of classical devices?"

Irina Novikova, Physics Professor, William & Mary

In an atomic magnetometer, a laser "tunes" a gas of atoms into a precise quantum state, which makes the gas transparent to the laser light. When a magnetic field appears, it interferes with this tuning, causing the atoms to absorb the light again. This change in magnetic field is measured by a detector.

But even the best magnetometers run into a barrier known as the standard quantum limit. Because light is made of discrete photons that arrive randomly, the measurement contains a kind of built-in quantum noise, called shot noise, similar to static in a radio signal. This randomness limits the device's sensitivity to minute changes in magnetic fields.

Novikova's group strives to overcome this quantum noise limitation by creating so-called "twin beam squeezed light." By passing a probe laser light through rubidium vapor in the presence of another strong laser field, they generate a second beam with quantum fluctuations nearly identical to those of the probe. This allows the researchers to know what the noise is and remove it, increasing the magnetometer's sensitivity - similar to how noise-canceling headphones work by detecting ambient noise and canceling it out.

A $1 million grant from the National Science Foundation supports Novikova, along with several other W&M professors and external collaborators, as they advance research on quantum magnetic field detection.

Just this year, the Physics Department joined W&M's new School of Computing, Data Science & Physics. To learn more, visit cdsp.wm.edu.

Catherine Tyson, Communications Specialist

College of William and Mary published this content on December 18, 2025, and is solely responsible for the information contained herein. Distributed via Public Technologies (PUBT), unedited and unaltered, on December 18, 2025 at 16:51 UTC. If you believe the information included in the content is inaccurate or outdated and requires editing or removal, please contact us at [email protected]