  The induced fractional zero-point canonical angular momentum on charged
particles by the Aharonov - Bohm (AB) vector potential is realized via modified
combined traps. It explores new features for this type of quantum effects: In a
limit of vanishing mechanical kinetic energy the AB vector potential alone
cannot induce a fractional zero-point canonical angular momentum on charged
particles at the quantum mechanical level in the AB magnetic field-free region;
But for the case of the AB vector potential with another one of a "spectator"
magnetic field the AB vector potential induces a fractional zero-point
canonical angular momentum in the same limit. The "spectator" one does not
contribute to such a fractional zero-point quantity, but plays essential role
in guaranteeing non-trivial dynamics survived in this limit at the quantum
mechanical level. These results are significance in investigations of the AB
effects and related fields for both theories and experiments.
