Researchers at the University at Buffalo have expanded the truncated Wigner approximation to simulate complex quantum systems on ordinary laptops, bypassing the need for supercomputers. This advancement, detailed in a September study in PRX Quantum, simplifies quantum dynamics for real-world applications. The method targets dissipative spin dynamics, making advanced physics accessible to more scientists.
Physicists have long relied on supercomputers or artificial intelligence to model the trillion possible configurations in quantum systems. However, a team at the University at Buffalo has upgraded the truncated Wigner approximation (TWA), a semiclassical technique from the 1970s, to handle these challenges on consumer-grade computers.
The expanded TWA now applies to dissipative spin dynamics, where particles interact with external forces and lose energy, unlike the isolated systems it previously limited to. "Our approach offers a significantly lower computational cost and a much simpler formulation of the dynamical equations," says corresponding author Jamir Marino, PhD, assistant professor of physics in the UB College of Arts and Sciences. The study, published in September in PRX Quantum by the American Physical Society, transforms dense quantum equations into a user-friendly conversion table.
Marino, who joined UB this fall after starting the work at Johannes Gutenberg University Mainz in Germany, collaborated with former students Hossein Hosseinabadi and Oksana Chelpanova, now a postdoctoral researcher in his UB lab. The research received funding from the National Science Foundation, the German Research Foundation, and the European Union.
Previously, applying TWA required re-deriving complex math for each problem, deterring widespread use. Now, "Physicists can essentially learn this method in one day, and by about the third day, they are running some of the most complex problems we present in the study," Chelpanova says. Marino notes, "Plenty of groups have tried to do this before us. It's known that certain complicated quantum systems could be solved efficiently with a semiclassical approach. However, the real challenge has been to make it accessible and easy to do."
This tool aims to reserve supercomputers for systems with states exceeding the number of atoms in the universe, allowing laptops to tackle many quantum phenomena efficiently. The journal reference is: Hossein Hosseinabadi, Oksana Chelpanova, Jamir Marino. User-Friendly Truncated Wigner Approximation for Dissipative Spin Dynamics. PRX Quantum, 2025; 6 (3) DOI: 10.1103/1wwv-k7hg.