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Tweaking Einstein on the Nature of Light

It makes sense to this former Midwesterner that Alan Kostelecky can compare light to waves propagating across a field of grain. After all, Kostelecky works at Indiana University, in a state where fields of grain are not so far from view. The theoretical physicist argues in research published online today in Physical Review D that we could consider light as the result of small violations of relativity, which compare not only to waving wheat but to “…a shimmering of ever-present vectors in empty space.”

Having seen my share of winds rippling across wheat fields, I know one thing: a propagating wave in a nearby crop comes with a sense of directionality. You know which way the wind is coming from, and how it’s affecting the local environment. Thinking of light in such terms is a far cry from a view with a much longer pedigree, that light depends upon an an underlying symmetry that is built into nature itself.

Waving wheat in the windThink of symmetry this way: Spacetime in the Einstein model has no preferred or distinguishable direction; this proposition is known as Lorentz invariance. A break from the Einsteinian view would occur if, for example, an underlying energy field permeated the universe, allowing interactions with particles that created directionality, just as a magnetic field favors a particular orientation in spacetime. Another possibility: finding subtle differences in the behavior of matter and antimatter could undermine the presumed symmetry and suggest a deeper solution.

Kostelecky and co-author Robert Bluhm of Colby College say that light may indeed break such symmetry. “Nature’s beauty is more subtle than perfect symmetry,” Kostelecky said. “The underlying origin of light may be another example of this subtlety.” What relativity may provide is a highly accurate approximation of how the universe works, but perhaps not the final answer. Variations in relativity could be clues in the attempt to build a true unified theory.

If light is somehow creating tiny violations of Einsteinian relativity, how could such effects be tested? The authors answer that equipment from particle accelerators to atomic clocks may be able to tell us that there are asymmetries between some particles and antiparticles, and perhaps cyclic variations in their behavior dependent on the Earth’s rotation. Much experimental work lies ahead, and you can get details galore in a FAQ at Kostelecky’s Web site.

So is relativity wrong? Not any more than Newtonian physics is ‘wrong,’ the point being that each is valid within the parameters of the tests that have been devised to measure it. But studying odd effects around the edges can expand our view, just as oddities in the way stars shifted behind a solar eclipse in 1919 helped us to confirm an Einsteinian understanding of a previously Newtonian view of orbital mechanics. An article called “Is Special Relativity Wrong?” on the American Institute of Physics news site offers useful background.

A preprint of the paper “Spontaneous Lorentz Violation, Nambu-Goldstone Modes, and Gravity” can be found at the ArXiv site. See Kostelecky’s site for a useful page containing animations on the topic of breaking spacetime symmetries. A University of Indiana press release on Kostelecky and Bluhm’s recent work is here.

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  • ljk January 8, 2009, 10:28

    Physicist Offers Foundation For Uprooting A Hallowed Principle Of Physics

    by Staff Writers

    Bloomington IN (SPX) Jan 08, 2009

    Physicists at Indiana University have developed a promising new way to identify a possible abnormality in a fundamental building block of Einstein’s theory of relativity known as “Lorentz invariance.” If confirmed, the abnormality would disprove the basic tenet that the laws of physics remain the same for any two objects traveling at a constant speed or rotated relative to one another.

    IU distinguished physics professor Alan Kostelecky and graduate student Jay Tasson take on the long-held notion of the exact symmetry promulgated in Einstein’s 1905 theory and show in a paper to be published in the Jan. 9 issue of Physical Review Letters that there may be unexpected violations of Lorentz invariance that can be detected in specialized experiments.

    Full article here:


  • ljk August 17, 2009, 10:17

    Testing Einstein’s special relativity with Fermi’s short hard gamma-ray burst GRB090510

    Authors: Fermi GBM/LAT Collaborations

    (Submitted on 13 Aug 2009)

    Abstract: Gamma-ray bursts (GRBs) are the most powerful explosions in the universe and probe physics under extreme conditions. GRBs divide into two classes, of short and long duration, thought to originate from different types of progenitor systems. The physics of their gamma-ray emission is still poorly known, over 40 years after their discovery, but may be probed by their highest-energy photons.

    Here we report the first detection of high-energy emission from a short GRB with measured redshift, GRB 090510, using the Fermi Gamma-ray Space Telescope. We detect for the first time a GRB prompt spectrum with a significant deviation from the Band function. This can be interpreted as two distinct spectral components, which challenge the prevailing gamma-ray emission mechanism: synchrotron – synchrotron self-Compton.

    The detection of a 31 GeV photon during the first second sets the highest lower limit on a GRB outflow Lorentz factor, of >1200, suggesting that the outflows powering short GRBs are at least as highly relativistic as those powering long GRBs.

    Even more importantly, this photon sets limits on a possible linear energy dependence of the propagation speed of photons (Lorentz-invariance violation) requiring for the first time a quantum-gravity mass scale significantly above the Planck mass.

    Comments: Supplementary Material is available at this http URL — Corresponding authors: J. Granot (j.granot@herts.ac.uk), S. Guiriec (sylvain.guiriec@nasa.gov, sylvain.guiriec@lpta.in2p3.fr), M. Ohno (ohno@astro.isas.jaxa.jp) and V. Pelassa (pelassa@lpta.in2p3.fr)

    Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

    Cite as: arXiv:0908.1832v1 [astro-ph.HE]

    Submission history

    From: Sylvain Guiriec [view email]

    [v1] Thu, 13 Aug 2009 18:14:12 GMT (1469kb)