Physicists at the University of Oxford have recreated a quantum effect in which a particle is influenced by a magnetic field without ever entering it. The experiment, reported in Nature Physics, used a hybrid quantum computer combining trapped-ion qubits with quantum oscillators. The team showed that a simulated magnetic flux could bring a particle's movement to a complete stop through quantum interference.
First predicted by Yakir Aharonov and David Bohm in 1959, the effect describes how a charged particle traveling around a region of magnetic flux can undergo a measurable change in quantum phase, even if its path stays outside the field. The Oxford group encoded the magnetic flux directly into entangled qubits, allowing it to become part of the evolving quantum system rather than a fixed external condition. Two qubits represented gauge fields, while two quantum oscillators represented matter at different locations in a small loop.
The work began in 2022 with lead author Sebastian Saner, Oana Bazavan, and colleagues, in collaboration with Alejandro Bermudez at the Instituto de Física Teórica in Madrid. Their goal was to simulate lattice gauge theories, mathematical models used in particle physics that describe how matter interacts with fundamental force fields. Such systems quickly become too complex for conventional computers, and the team's approach offers a way to observe their behavior directly.