  The Aharonov-Bohm effect is a fundamental topological phenomenon with a wide
range of applications. It consists of a charge encircling a region with a
magnetic flux in a superposition of wave packets having their relative phase
affected by the flux. In this work, we analyze this effect using an entropic
measure known as realism, originally introduced as a quantifier of a system's
degree of reality and mathematically related to notions of global and local
quantum coherence. More precisely, we look for observables that lead to
gauge-invariant realism associated with the charge before it completes its
loop. We find that the realism of these operators has a sudden change when the
line connecting the center of both wave packets crosses the solenoid. Moreover,
we consider the case of a quantized magnetic-field source, pointing out
similarities and differences between the two cases. Finally, we discuss some
consequences of these results.
