Manipulating quantum spins by spin-polarized current: an approach based upon $\mathcal{PT}$ -symmetric quantum mechanics

We propose here a quantum processor based upon single-molecule magnets and spin transfer torque described by $\mathcal{PT}$-symmetric quantum mechanics. In recent years $\mathcal{PT}$-symmetric Hamiltonians have been used to obtain stability thresholds of various systems out of equilibrium. One such concern is the magnetization reversal due to the spin transfer torque generated by a spin-polarized current. So far the studies of this problem have mostly focused on a classical limit of a large spin. In this work we are discussing spin tunneling and quantum dynamics of a small spin induced by a spin polarized current within a $\mathcal{PT}$-symmetric theory. Furthermore, this description can be used for manipulating spin qubits by electric currents.