Weak value picture on quantum observables: gauge-invariant vector
potentials
- URL: http://arxiv.org/abs/2003.06992v2
- Date: Fri, 30 Apr 2021 12:04:31 GMT
- Title: Weak value picture on quantum observables: gauge-invariant vector
potentials
- Authors: Sunkyu Yu, Xianji Piao, Namkyoo Park
- Abstract summary: We find a new gauge-invariant quantity by applying a "weak value picture"
The obtained vector potential corresponds to the weak value of the projected momentum operator.
This weak value decomposition approach will lead to the extraction of new measurable quantities.
- Score: 0.0
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: The conservation of physical quantities under coordinate transformations,
known as gauge invariance, has been the foundation of theoretical frameworks in
both quantum and classical theory. The finding of gauge-invariant quantities
has enabled the geometric and topological interpretations of quantum phenomena
with the Berry phase, or the separation of quark and gluon contributions in
quantum chromodynamics. Here, with an example of quantum geometric
quantities-Berry connection, phase, and curvature-we extract a new
gauge-invariant quantity by applying a "weak value picture". By employing
different pre- and post-selections in the derivation of 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. The local nature of this quantity is demonstrated with an example of
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 will lead to the extraction of
new measurable quantities from traditionally unobservable quantities.
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