  We predict that a charge under the influence of a quantum electrodynamic
potential exhibits a force-free Aharonov-Bohm effect. The specific system
considered in this study is a superconducting charge qubit nonlocally
interacting with a cavity electromagnetic field. We find that this nonlocal
interaction gives rise to remarkable quantum electrodynamic phenomena such as
vacuum Rabi splitting and oscillation, and Lamb shift, under the condition that
the qubit is located in an electromagnetic-field-free region. Our result can be
verified in a realistic experimental setup, and provides a new approach of
investigating the Aharonov-Bohm effect combined with quantum electrodynamics.
