I agree, but you don't need thermal noise to simulate the effects quantum randomness. You can use actual quantum randomness! The number of photons absorbed in a photodetector is determined by quantum randomness, because some of them are absorbed and some of them pass trough. IIRC a camera with a CCD is enough to measure individual photons.

(Nevertheless, in my opinion neither of this is necessary to simulate consciousness, a good PRNG would be enough, but we should wait a few years until this is confirmed.)