Interpreting Quantum Interference Using a Berry’s Phase-like Quantity

Anthony Laing

M. J. Rave

We show that quantum interference can be classically interpreted in terms of a phase invariant quantity, not unlike the Berry's phase. Under this interpretation, closed loops in time become fundamental quantum entities, and all quantum states become periodic. Decoherence is then seen to occur naturally as a consequence. This formalism, although counterintuitive, provides a useful way of assigning ``classical'' meaning to quantum probabilities.

Chris Philippidis, Christopher Dewdney, Basil J. Hiley

K M Cheng, P. C. W. Fung

The authors discuss certain properties of Berry's phases in two quantum systems with supersymmetrically related Hamiltonians and derive an explicit expression for the difference in their Berry's phases. Moreover, they obtain an expression for a topological quantity which can be interpreted in term of holonomy, and which contains the Berry's phase and is invariant in the two supersymmetrically related quantum systems. They take two examples to illustrate their findings. The first one is the example of the Aharonov-Bohm effect in which the Berry's phases of the two supersymmetrically related quantum systems are equal. The second example is a system with a spin-1/2 particle in a time varying magnetic field. They obtain the stated topological quantity and, in their analysis, they discover that this quantity is corresponding to the essential gauge transformation in such systems.

Sunkyu Yu, Xianji Piao, Namkyoo Park

The conservation of quantities or dynamics under coordinate transformations, known as gauge invariance, has been the foundation of theoretical frameworks in physics. The finding of gauge-invariant quantities has provided a new way of understanding physical problems, as shown in geometric and topological interpretations of quantum phenomena with the Berry phase, or in the separation of quark and gluon contributions in quantum chromodynamics. Here, focusing on the Berry phase, we extract a new gauge-invariant quantity. By employing different pre- and post-selections in the Berry phase in the context of weak values, we derive the gauge-invariant vector potential from the Berry connection that is originally gauge-dependent, and show that the obtained vector potential corresponds to the weak value of the projected momentum operator in the parameter space. The local nature of this quantity is demonstrated with the Aharonov-Bohm effect, proving that this gauge-invariant vector potential can be interpreted as the only source of the Berry curvature in the magnetic field. This weak value decomposition approach could lead to the identification of new measurable quantities from traditionally unobservable quantities.

A. Shalom, J. Žák