Braiding with Borromean Rings in (3+1)-Dimensional Spacetime

Abstract: While winding a particle-like excitation around a loop-like excitation yields the celebrated Aharonov-Bohm phase, we find a distinctive braiding phase in the absence of such mutual winding. In this work, we propose an exotic particle-loop-loop braiding process, dubbed the \emph{Borromean-Rings braiding}. In the process, a particle moves around two unlinked loops, such that its trajectory and the two loops form the Borromean-Rings or more general Brunnian links. As the particle trajectory does not wind with any of the loops, the resulting braiding phase is fundamentally different from the Aharonov-Bohm phase. We derive an explicit expression for the braiding phase in terms of the underlying Milnor's triple linking number. We also propose Topological Quantum Field Theories consisting of an $AAB$-type topological term which realize the braiding statistics.