Physicists Transfer Information Between Matter And Light

KingFishKingFish
edited November 2004 in Science & Tech
A team of physicists at the Georgia Institute of Technology has taken a significant step toward the development of quantum communications systems by successfully transferring quantum information from two different groups of atoms onto a single photon.
An infrared write pulse (780 nm wavelength) is split into two beams by a polarizing beam splitter (PBS1) focused into two regions of the atomic cloud about 1 mm apart and passed through it. The light induces spontaneous Raman scattering of a signal photon with slightly shorter wavelength. The classical light is dumped away by the PBS2, while the quantum signal photon is transmitted by the dichroic mirror DM, passed through an arbitrary polarization state transformer R and a polarizer PBS5, and is directed onto a single-photon detector D1. Detection of the signal photon by D1 prepares the atomic ensemble in any desired state and thereby concludes the preparation of the quantum memory qubit. Following memory state preparation, the read-out stage is performed. After a user-programmable delay a classical coherent read pulse of 795 nm wavelength illuminates the two atomic ensembles. This results in a single (i.e., quantum) idler photon being emitted in the forward direction. This accomplishes a transfer of the memory state onto the idler. The idler is reflected off the dichroic mirror DM. After passing through the state transformer R and PBS6, the two polarization components are directed onto single-photon detectors (D2, D3) thus accomplishing measurement of the idler photon, and hence the memory qubit, in a controllable arbitrary basis.
Source: Science Daily

Comments

  • croc_croc_ New
    edited October 2004
    eh?
  • CyrixInsteadCyrixInstead Stoke-on-Trent, England Icrontian
    edited October 2004
    Sounds interesting. Although I hardly understand it, it seems to be along the lines of something I learned about at University.

    At the uni I went to they had a long history of research in computing. Years ago the uni had a giant bath of mercury under the library (rumoured to be still there as there's no way to dispose of the mercury).

    Because the mercury slows down the time it takes a pulse of air to reach the other end, some manner of memory can be achieved. Can't remember any more than that.

    What a useless post :confused:

    ~Cyrix
  • EnverexEnverex Worcester, UK Icrontian
    edited October 2004
    croc_ wrote:
    eh?
  • ShivianShivian Australia
    edited October 2004
    So basically they can read/write a single quantum memory bit? Sounds good to me :thumbsup:
  • TimTim Southwest PA Icrontian
    edited November 2004
    Now why didn't I think of that? :scratch:
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