Physical learning machines require noise to learn. They are also necessarily dissipative. See https://arxiv.org/abs/2209.11954 https://arxiv.org/abs/2209.11954

Physical learning machines require noise to learn. They are also necessarily dissipative. See https://arxiv.org/abs/2209.11954 https://arxiv.org/abs/2209.11954. The key is to engineer the noise to maximise the learning rate. In classical devices, stochastic switching is controlled by temperature through the Kramers rate. This means kT controls energy loss. If you use dissipative quantum tunnelling this is not the true thermodynamic lower bound. Any quantum nonlinear dissipative system, with a far from equilibrium steady state, is a good case to consider. Dispersive optical bistability, realised in SC quantum circuits, is the way to go. And quantum error correction is unnecessary.