Fig. 1: A spintronic quantum information engine.
From: Atom-level electronic physicists are needed to develop practical engines with a quantum advantage
Spin↑/↓ is in blue/red. The spin degeneracy of the paramagnetic atom’s unpaired electron is dynamically lifted by transport fluctuations (blue on left) with spin-selecting electrodes. Interactions of different strength on either side (thinner red arrow on right), along with spin selection (gray crosses) break the detailed balance of transport. Thermal fluctuations (circular purple arrows) provide the energy to promote the electron to an excited quantum state. The quantum passivation of this excited state, and the spin measurement by the electrodes, effectively generate ergotropy, leading to a dc voltage Voutput. Additional quantum assets, such as entanglement between spin states (green arrow), are described in ref. 7.
