Shape from sound: New methods to probe the universe

Apr. 3, 2013 ? As the uni?verse expands, it is con?tin?u?ally sub?jected to energy shifts, or "quan?tum fluc?tu?a?tions," that send out lit?tle pulses of "sound" into the fab?ric of space?time. In fact, the uni?verse is thought to have sprung from just such an energy shift.

A recent paper in the jour?nal Phys?i?cal Review Let?ters reports a new math?e?mat?i?cal tool that should allow one to use these sounds to help reveal the shape of the uni?verse. The authors recon?sider an old ques?tion in spec?tral geom?e?try that asks, roughly, to what extent can the shape of a thing be known from the sound of its acoustic vibra?tions? The researchers approached this prob?lem by break?ing it down into small work?able pieces, accord?ing to author Tejal Bhamre, a Prince?ton Uni?ver?sity grad?u?ate stu?dent in the Depart?ment of Physics.

To under?stand the authors' method, con?sider a vase. If one taps a vase with a spoon, it will make a sound that is char?ac?ter?is?tic of its shape. Sim?i?larly, the tech?nique Bhamre and her coau?thors devel?oped could, in prin?ci?ple, deter?mine the shape of space?time from the per?pet?ual ring?ing caused by quan?tum fluctuations.

The researchers' tech?nique also pro?vides a unique con?nec?tion between the two pil?lars of mod?ern physics -- quan?tum the?ory and gen?eral rel?a?tiv?ity -- by using vibra?tional wave?lengths to define the geo?met?ric prop?erty that is spacetime.

Bhamre worked with coau?thors David Aasen, a physics grad?u?ate stu?dent at Cal?tech, and Achim Kempf, a Water?loo Uni?ver?sity pro?fes?sor of physics of information.

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Story Source:

The above story is reprinted from materials provided by Princeton University. The original article was written by Mor?gan Kelly.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. David Aasen, Tejal Bhamre, Achim Kempf. Shape from Sound: Toward New Tools for Quantum Gravity. Physical Review Letters, 2013; 110 (12) DOI: 10.1103/PhysRevLett.110.121301

Note: If no author is given, the source is cited instead.

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Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/top_science/~3/vTU4S4Dh68g/130403131359.htm

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