  The charge character of Andreev bound states (ABSs) in a three-terminal
semiconductor-superconductor hybrid nanowire was measured using local and
nonlocal tunneling spectroscopy. The device is fabricated using an epitaxial
InAs/Al two-dimensional heterostructure with several gate-defined side probes.
ABSs are found to oscillate around zero as a function of gate voltage, with
modifications of their charge consistent with theoretical expectations for the
total Bardeen-Cooper- Schrieffer (BCS) charge of ABSs.
