| EPSRC Reference: |
EP/D032970/1 |
| Title: |
Sensitivity to Gravity of Driven Cold-Atom Dynamics |
| Principal Investigator: |
Gardiner, Professor SA |
| Other Investigators: |
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| Project Partners: |
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| Department: |
Physics |
| Organisation: |
Durham, University of |
| Scheme: |
First Grant Scheme Pre-FEC |
| Starts: |
01 October 2005 |
Ends: |
30 September 2008 |
Value (£): |
125,909
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| No relevance to Underpinning Sectors |
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Summary on Grant Application Form |
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The atom-optical delta-kicked accelerator consists of a cloud of cooled atoms (microkelvin to nanokelvin temperatures), allowed to fall freely with gravity through a pulsed laser standing wave. In the parameter regime under consideration, the effect of the laser standing wave is to exert a force on the atoms which varies sinusoidally in space, parallel to the force of gravity. The pulses are sufficiently short that they can be considered to be instantaneous, which gives rise to the term delta (instantaneous) kicks, and the term accelerator is due to the natural acceleration caused by gravity, even in the absence of the aforementioned kicks.The interplay of forces present causes a number of very interesting quantum mechanical effects, effects for which there are no obvious parallels in classical (non-quantum) dynamics. These are caused by special resonance conditions, to do with the frequency of the kicks imparted, or pulses emitted by the laser standing wave, and the exact value of the local gravitational acceleration. The visible manifestation of these quantum-mechanical resonance effects, dubbed quantum accelerator modes and gravitationally-mediated quantum resonances , is that a large proportion of the atoms accelerate to a greatly increased absolute velocity, in a way which is strongly dependent on the kicking frequency and the local gravitational acceleration.The kicking frequency can be easily varied, and in an effective sense the ravitational acceleration can too, in that if the standing wave is formed by two counterpropagating laser beams with a controllable frequency difference, then the standing wave can be made to accelerate in space, which mimics the effect of a different value of the local gravitional acceleration.The aim of this research project is to investigate general properties of this very interesting dynamical system, and its suitability as a high-precision measurer of the local gravitational acceleration. This will necessarily involve including experimental realities, such as the effects of temperature, atom-atom interactions, and imperfections and inhomogeneities in such things as the initial trapping conditions of the cloud of atoms and the laser field carrying out the (near) instantaneous kicking. The focus will be on using the observation of gravitationally mediated quantum resonances as the acceleration of the laser standing wave is scanned through a wide variety of values. Determining at which values of the standing wave acceleration that such quantum resonances occur directly informs us of the value of the local gravitational acceleration
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Key Findings |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Potential use in non-academic contexts |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Impacts |
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| Description |
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk |
| Summary |
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| Date Materialised |
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Sectors submitted by the Researcher |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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