May 6 2010
Before a quantum effect such as resonance fluorescence-resulting from the interaction of light with atoms-can be applied to quantum computing schemes, scientists need to replicate it in the laboratory. Thus far, however, efforts using artificial atoms made from superconducting circuits have been unsuccessful. Now, resonance fluorescence of a single artificial atom has been demonstrated by researchers from the NEC Nano Electronics Laboratory in Tsukuba and the RIKEN Advanced Science Institute in Wako.
Resonance fluorescence occurs when a light beam with an energy that matches an atom’s resonance energy gets absorbed by the atom and then re-emitted in random directions. As resonance fluorescence can be used to couple two photons, or light particles, scientists are keen to exploit this effect in quantum computing operations. However, this effect in atoms is too small to be useful for practical applications since photons and atoms interact very weakly due to their small size, according to Jaw-Shen Tsai, who led the research team.
To circumvent this problem, researchers created artificial atoms on computer chips, where the interaction between light and the artificial atom can be optimized. “With a solid-state device such as ours, made from superconducting circuits, the coupling can be very strong,” says Tsai.