  The Zeeman interaction is a quantum mechanical effect that underpins
spin-based quantum devices such as spin qubits. Typically, identification of
the Zeeman interaction needs a large out-of-plane magnetic field coupled with
ultralow temperatures, which limits the practicality of spin-based devices.
However, in two-dimensional (2D) semiconductor holes, the strong spin-orbit
interaction causes the Zeeman interaction to couple the spin, the magnetic
field, and the momentum, and has terms with different winding numbers. In this
work, we demonstrate a physical mechanism by which the Zeeman terms can be
detected in classical transport. The effect we predict is very strong, and
tunable by means of both the density and the in-plane magnetic field. It is a
direct signature of the topological properties of the 2D hole system, and a
manifestation in classical transport of an effect stemming from relativistic
quantum mechanics. We discuss experimental observation and implications for
quantum technologies.
