The keyword there is, “in principle,” which is even less than “on paper.” Essentially if you had elements which asymptotically approached frictionless interacti

The keyword there is, “in principle,” which is even less than “on paper.” Essentially if you had elements which asymptotically approached frictionless interactions, and you had an idealized power source... sure, less entropy than firing electrons through Si. Things ignored to make that work: Materials which are likely to ever exist. A degree of mechanical perfection on the order of one of NASA’s fused quartz spheres. An idealized means of transferring energy to the device. A perfect vacuum. Perfect shielding from external influence, especially vibration. The faster you crank this up, the more energy is in the form of Ke in the device, and like a flywheel, it may come to resemble a bomb.