The ability to observe energy dissipation in a quantum system is demonstrated in a study published online this week in Nature. The cryogenic thermal imaging technique reported in the paper may help uncover new insights into the microscopic behaviour of quantum systems, such as those used for the storage of quantum information.
Dissipation - the irreversible transformation of energy from one form into another (essentially unusable) form - is one of the main characteristics that distinguish quantum and classical phenomena. Dissipation demolishes quantum information and therefore needs to be very weak to preserve a quantum state, making dissipation difficult to measure. Existing techniques for imaging such energy flows are not sufficiently sensitive and are unable to operate at the extremely low temperatures required for studying quantum systems.
Dori Halbertal and colleagues developed a superconducting quantum interference device mounted on the tip of a sharp pipette (SQUID-on-tip) capable of imaging the thermal signature of extremely-low-energy dissipation processes with much greater resolution and sensitivity than existing methods can. The authors use their nanoscale thermometer to image dissipation in carbon nanotubes and graphene.