Northeastern physicist receives an NSF CAREER award to explore the potential of fractons in computing, materials science and inspiring education initiatives.
Most people leave high school with the basic knowledge that everything in the physical world consists of atoms — made up of protons, neutrons and electrons.
Professor of physics Yizhi You says the limited mobility of fractons makes them a promising option for advancing quantum hardware and building more efficient quantum computers.
We also know about the three common states of matter we encounter daily — solid, liquid and gas.
A theoretical physicist like Yizhi You, a professor at Northeastern University, studies the tiny world of subatomic particles. She examines how these particles interact with each other in materials.
These interactions can lead to unusual states of matter and phenomena, like quasiparticles — when groups of particles work together and behave as if they were a single particle.
You recently received a prestigious CAREER award from the National Sciences Foundation to explore and advance understanding of an unusual phase of matter called the “fracton phase.”
“It challenges our basic understanding of what elementary particles are,” You says.
Fractons are groups of tiny particles that appear in certain materials and behave in a unique way. Unlike electrons or protons, they can’t move on their own and usually need to join with other fractons to move.
“This intriguing property is transforming our understanding of matter and sparking interest across diverse fields such as quantum materials, quantum field theory and quantum information science,” You says.
The limited mobility of fractons offers exciting potential for breakthroughs in emerging technologies, she says, especially in developing quantum hardware and efficient quantum computers.
Modern computers don’t yet take full advantage of the potential of quantum mechanics for solving complex problems. Theoretical physicists, including You, believe that quantum computing could create a new way of processing information, making it much faster.
Quantum computing, however, faces significant challenges.
One of the most fascinating ideas in quantum mechanics, You says, is entanglement. This happens when two particles become connected so that if you measure one, you instantly know the state of the other, no matter how far apart they are.
“For example, if one particle is polarized in a spin-up direction [meaning that it is spinning upwards] and we make measurements and know this information, we will immediately know that the other particle should have the same patterns,” You says.
Quantum computing uses entanglement to solve certain problems faster than traditional computers. Entanglement is also used in secure communication systems like quantum key distribution, which provides strong protection against hacking.
Quantum systems are prone to decoherence, a process where particles rapidly lose their quantum properties due to interactions with the environment.
For example, single electrons can move on their own. However, when they interact with their surroundings — like heat — they start to fluctuate randomly. As they collide and exchange energy and momentum, their motion becomes affected by these changes. These interactions can break down any coordinated behavior among the electrons, leading to disorder and chaotic motion in the system.
“In most cases entanglement would diminish immediately if we have decoherence, or if your quantum material interacts with the environment,” You says.
This poses a lot of challenges for quantum computing, including information storing and computing errors. That’s why researchers are searching for a quantum material that stays stable longer, she says, so that it could be used for quantum computing or as storage in a quantum computer.
Since fractons must move in a group, more energy is required to move them, You says. At low temperatures, the thermal fluctuations of fractons are minimal, leading to slower decoherence. This makes them a promising option for building stable quantum memory.
Since the mobility and other properties of fractons depend on the collective behavior of particles, even in the presence of decoherence, You says, there can still be residual quantum correlations between fractons.
Fractons could also be used to create scalable quantum simulators for scientific research.
Current materials have significant limitations, You says, when it comes to studying how electrons and ions interact and their effects on material properties. For example, it’s difficult to adjust the strength of these interactions.
If fractons can be controlled, You hopes to use them to study or simulate non-equilibrium properties, which are hard to explore in traditional solid-state physics. These properties appear in materials when they are out of balance with their surroundings, such as when temperature, pressure or chemical composition varies across the system.
The CAREER award also supports educational and outreach programs to train, mentor and inspire students to pursue careers in STEM. As part of these efforts, You plans to support female students and postdocs in STEM through the “Women in Quantum Era” seminar series.
Additionally, she wants to inspire future STEM students with a “Science Inspired by Art” workshop, which uses activities like modular origami and decorative knots to help participants explore geometry and related scientific concepts in an interactive way.