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Gravitational Relativistic Physics (GRP)

Laser Cooling and Atomic Physics

    PAST:   None
    PRESENT: Ongoing Research

Launch Date: proposed
Mission Duration: 6 months
Principle Investigator: Prof. Dan Heinzen, Univerisity of Texas at Austin


EDM X image

When you have positive and negative electric charges close to each other they create a dipole field. Scientists want to know if an electron has an electric dipole moment, which would occur if the electric charge of an electron is not spherically symmetric.

The EDM-X experiment tests the conditions of atoms placed in an electric field, by examining supercooled atoms to detect the effects of an electric dipole moment on an electron. To supercool atoms, the atoms are brought to a stop with "optical glue," by hitting them from six sides by lasers tuned to the correct frequency to slow the motions of the atoms.

Usually atoms of the "noble" gases such as rubidium or cesium are used. These are "the right kind of atoms" because it is easy to tune to the frequency for exciting the electrons to higher energy states. The laser causes the atoms to absorb the photon from the laser light, and then to emit it in a random direction. This absorption-reemission process, when repeated many times, brings the atoms to a very low velocity, which cools them down, very nearly to absolute zero. By cooling the atoms scientists get a better-defined energy level and can conduct a variety of experiments on them.

After the atoms are cooled, an electric field is placed on the atoms, and they are measured to see if they have a dipole moment.

The most accurate results from this experiment are only possible in the microgravity of space because this environment allows the atoms to remain in their cooled state for a longer time and they can then be studied without gravity interfering. EDM-X and similar experiments will be conducted in orbit to be free for gravity's effects. The facility has the capability to create vacuums, to house lasers for slowing the atoms, to contain additional lasers for studying energy levels of atoms, and to contain other devices to allow physics experiments to operate

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