  Spatial separation of Majorana zero modes distinguishes trivial from
topological midgap states and is key to topological protection in quantum
computing applications. Although signatures of Majorana zero modes in tunneling
spectroscopy have been reported in numerous studies, a quantitative measure of
the degree of separation, or nonlocality, of the emergent zero modes has not
been reported. Here, we present results of an experimental study of nonlocality
of emergent zero modes in superconductor-semiconductor hybrid nanowire devices.
The approach takes advantage of recent theory showing that nonlocality can be
measured from splitting due to hybridization of the zero mode in resonance with
a quantum dot state at one end of the nanowire. From these splittings as well
as anticrossing of the dot states, measured for even and odd occupied quantum
dot states, we extract both the degree of nonlocality of the emergent zero
mode, as well as the spin canting angles of the nonlocal zero mode. Depending
on the device measured, we obtain either a moderate degree of nonlocality,
suggesting a partially separated Andreev subgap state, or a highly nonlocal
state consistent with a well-developed Majorana mode.
