Researchers develop method to control the quantum states of single electron spins using spin-polarized currents
Researchers from ETH Zurich recently developed a method to control the quantum states of single electron spins using spin-polarized currents, which could enhance quantum computing technologies. The new technique offers more precise, localized control compared to traditional methods using electromagnetic fields, potentially improving the manipulation of quantum states in devices like qubits.
Control over quantum systems is typically achieved by time-dependent electric or magnetic fields. Alternatively, electronic spins can be controlled by spin-polarized currents. In their recent work, the team demonstrated coherent driving of a single spin by a radiofrequency spin-polarized current injected from the tip of a scanning tunneling microscope into an organic molecule. With the excitation of electron paramagnetic resonance, the scientists established dynamic control of single spins by spin torque using a local electric current. In addition, their work highlights the dissipative action of the spin-transfer torque, in contrast to the nondissipative action of the magnetic field, which allows for the manipulation of individual spins based on controlled decoherence.