Tuesday, June 03, 2008
Scientists take great pains not to disturb the coherence of quantum states through constant measurements. Israeli and German scientists recently collaborated to turn this technique on its head, using the measurement of quantum states to control thermodynamics (temperature) and entropy (settling). The scientists claim that in two-level quantum systems--like those used to represent quantum bits (q-bits)--the frequency with which they are measured controls both temperature and entropy. The approach could enable novel cooling schemes as well as instant-settling for atomic, molecular and solid-state devices. Both cooling and state purification, they claim, can be made to occur much more quickly than the normal time typically needed to achieve thermal equilibrium for cooling or feedback around a control loop for purification.
Posted by R. Colin Johnson at 7:03 AM