Measurement of noncommuting spin components using spin-orbit interaction

We propose a possible experiment aimed at a joint measurement of two noncommuting spin-1/2 components and analyze its physical meaning. We demonstrate that switching of a strong spin-orbit interaction, e.g., in a solid-state or a cold-atom system, for a short time interval simulates a simultaneous von Neumann measurement of the operators sigma(x) and sigma(y). With the spin dynamics mapped onto the quantum coordinate-space motion, such an experiment determines averages of sigma(x) and sigma(y) over the duration of the measurement, however short the latter may be. These time averages, unlike the instantaneous values of sigma(x) and sigma(y), may be evaluated simultaneously to an arbitrary accuracy.