Computing in Thermal Equilibrium With Dipole-Coupled Nanomagnets

In the 1970s, work at IBM by Charles Bennett suggested the possibility of a computer operating near thermal equilibrium and dissipating energy near the thermodynamic limits. Here, we demonstrate experimentally that a computing architecture based on dipole-coupled nanomagnets can operate near thermal equilibrium without the assistance of externally applied magnetic fields. The dynamics of digital signal propagation is demonstrated with micromagnetic simulation and then verified experimentally using time-lapse photoemission electron microscopy. A logic gate that computes using energy from the thermal bath without external fields is also demonstrated. Nanomagnetic logic circuits operating under these conditions are expected to dissipate energy near the fundamental thermodynamic limits of computation.