A quantum mechanics lab on a chip

Chip technology has evolved from the desire to further shrink the size of semiconductor devices. The high sensitivity of the electronic properties of nanostructured semiconductors can be used to detect humidity, temperature, magnetic fields and other fundamental quantities. This in turn can be used to use electronic devices for fluidic or biophysical measurements and drastically reduce the volume of such measurements. Small semiconductor devices on the other hand, if measured at low enough temperatures and other appropriate boundary conditions, clearly display quantum effects. The quantum mechanical properties of such small charged islands, also called artificial atoms, can be measured by transport experiments and an energy spectrum similar to the one of real atoms can be detected. A variety of other quantum systems, such as tunnel barriers or phase-coherent rings can also be realized with such techniques. By coupling different quantum circuits on a chip the charge flow can be monitored in a time-resolved fashion on the level of individual electrons. The perfection of such systems has advanced to a degree where basic quantum mechanical properties can be probed on a semiconductor chip.