Marrying matter and light
Peter Weiss
Despite centuries of scientific scrutiny, the ways in which light and matter affect each other remain only partly understood. To get a look at the most fundamental of light-matter interactions, physicists have been trapping one atom and one photon together between tiny mirrors (SN: 3/18/00, p. 191: Available to subscribers at http://www.sciencenews.org/articles/20000318/note19.asp). In such experiments in quantum physics, the photon and atom repeatedly merge and disengage, forming a blended entity of matter and light.
Now a U.S.-based research team and a Netherlands-Japan team are turning to an alternative experimental approach based on so-called artificial atoms: micrometer-scale structures made of metals that conduct electricity with no resistance. In a pair of independent reports in the Sept. 9 Nature, the teams present evidence that a microwave photon can merge with one of these artificial atoms and form a hybrid of light and matter.
Normally, photons have little or nothing to do with one another, but in these entities the scientists expect to see exotic events, such as the merging of two photons to form a more-energetic photon.
Robert J. Schoelkopf of Yale University, a leader of the U.S.-based team, says he and his colleagues plan on extending the work into potentially practical arenas, among them quantum-information processing. For example, he notes, it might be possible to make microchips bearing multiple artificial atoms that together can perform calculations by influencing one another's quantum states through a shared photon.
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References:
Chiorescu, I., et al. 2004. Coherent dynamics of a flux qubit coupled to a harmonic oscillator. Nature 431(Sept. 9):159–162. Abstract available at http://dx.doi.org/10.1038/nature02831.
Makhlin, Y., G. Schön, and A. Shnirman. 2004. The qubit and the cavity. Nature 431(Sept. 9):138.
Wallraff, A. … and R.J. Schoelkopf. 2004. Strong coupling of a single photon to a superconducting qubit using circuit quantum electrodynamics. Nature 431(Sept. 9):162–167. Abstract available at http://dx.doi.org/10.1038/nature02851.
Further Readings:
Weiss, P. 2003. One-atom laser: Trapped atom shoots steady light beam. Science News 164(Sept. 20):181. Available at http://www.sciencenews.org/articles/20030920/fob6.asp.
______. 2000. Photon-in-a-box slings atom into orbit. Science News 157(March 18):191. Available to subscribers at http://www.sciencenews.org/articles/20000318/note19.asp.
For additional information about Yale research on circuit quantum electrodynamics, go to http://www.eng.yale.edu/rslab/cQED/.
Sources:
Robert J. Schoelkopf
Departments of Applied Physics and Physics
Yale University
New Haven, CT 06520
From Science News, Volume 166, No. 14, October 2, 2004, p. 222.
