A method for measuring the real part of the weak value of spin using non-zero rest mass particles

Abstract

A method for measuring the real part of the weak (local) value of spin is presented using a variant on the original Stern-Gerlach apparatus. The experiment utilises metastable helium in the $2^3{\mathrm{S}}_1$ state. A full simulation using the impulsive approximation has been carried out and it predicts a displacement of the beam by ${\mathrm{\Delta }}_{\mathrm{w}}=17-33\mu \mathrm{m}$. This is on the limit of our detector resolution and we will discuss ways of increasing ${\mathrm{\Delta }}_{\mathrm{w}}$. The simulation also indicates how we might observe the imaginary part of the weak value.