Indirect quantum measurement of a single quantum spin

We establish the conditions to observe a single localized quantum spin View the MathML source using a tunneling current of electrons as the probe in an indirect quantum measurement. We show that a strong tunneling current, due to the shot noise, suppresses the spin dynamics, such as the spin precession in an external magnetic field (quantum Zeno effect), while a weak tunneling current preserves the spin precession but the oscillatory component of the current is of the same order as the noise. Within our semi-classical analysis we describe the physical requisites to observe a signature of quantum oscillations in the current–current correlation function.