Let quantum mechanics improve your images

Science: Images are superb conveyors of information. Recent research has shown how subtle quantum mechanical aspects of light can profoundly influence the nature of image formation.In the July 25 issue of Science, two important advances in this emerging area of quantum imaging are presented. Wagner et al. report on the behavior of two beams of light that are quantum mechanically entangled in position and direction of propagation--that is, the outcome of measurements on one beam depends on what sort of measurements have been performed on the other beam. Boyer et al. show that two image-bearing light beams can be entangled such that strong quantum correlations exist both between the two beams and between individual image features within each beam. They find two sorts of quantum correlations: The intensities of the two beams fluctuate in unison, at a level not permitted by classical statistics, and the noise in one part of the light field can be reduced, or "squeezed," at the expense of another part.