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Topic: Lorentz invariance

	Lorentz invariance and you \| Cosmic Variance
		That means that Lorentz invariance — the physical symmetry corresponding to rotations and changes of velocity — would be broken.
		Lorentz invariance is a cornerstone of relativity (and thus of all of modern physics), so breaking it is often thought to be bad.
		Amusingly enough, it’s the new experimental constraints on violating Lorentz invariance that get in our way — for a model of the type we consider to really work, the violation has to be strong in the early universe, and fade away by the time we are doing are experiments today.
	cosmicvariance.com /2005/10/25/lorentz-invariance-and-you (1720 words)

	Lorentz covariance - Wikipedia, the free encyclopedia
		In physics, Lorentz covariance is a key property of spacetime that follows from the special theory of relativity, where it applies globally.
		Lorentz violation refers to theories which are approximately relativistic when it comes to experiments that have actually been performed (and there are quite a number of such experimental tests) but yet contain tiny or hidden Lorentz violating corrections.
		Irrelevant Lorentz violating operators may be suppressed by a high cutoff scale, but they typically induce marginal and relevant Lorentz violating operators via radiative corrections.
	en.wikipedia.org /wiki/Lorentz_invariance (531 words)

	Breaking Lorentz symmetry (March 2004) - Physics World - PhysicsWeb
		Lorentz symmetry has so far withstood the tests of time, but in recent years theorists have begun to question whether it is indeed an exact symmetry of nature.
		Possible violations of Lorentz invariance are an ideal signal of new physics because nothing in the Standard Model of particle physics permits the violation of special relativity.
		Lorentz transformations between different co-ordinate frames ensure that the space-time interval and the value of the speed of light are the same for all inertial observers.
	physicsweb.org /articles/world/17/3/7 (4463 words)

	Physics news Update 775
		Lorentz invariance says that the laws of physics are the same for an observer at rest on the Earth or one who is rotated through some angle or traveling at a constant speed relative to the observer at rest.
		Looking for a crack in the universe in the form of a very faint field pervading the Cosmos, one that exerts a force on electron spin, would mean the end of Lorentz invariance.
		In fact, he said that something strange was happening at a measurement scale of about 70 microns; the most likely explanation of this, he conceded, was an experimental artifact.
	www.aip.org /pnu/2006/split/775-1.html (389 words)

	A Test of Local Lorentz Invariance
		We have compared the relative precession frequencies of Hg and Cs magnetometers as a function of the direction of an applied magnetic with respect to the fixed stars.
		The principle of local Lorentz invariance (LLI) requires that the result of any nongravitational experiment is independent of the velocity or orientation of the freely falling apparatus.
		Colladay and Kostelecky have developed a gauge invariant extension of the standard model that conveniently classifies the terms that violate LLI and CPT.{co} Several of these terms produce dipolar frequency shifts of the electron and neutron that depend on the orientation of their spin with respect to the fixed stars.
	www.amherst.edu /~physics/pages/hunter/LLI.html (2379 words)

	A New Interpretation of Special Relativity
		The Lorentz transformations relate wave measurements made in different frames of reference and the energy-momentum relation is a general property of soliton waves.
		Since the use of wave propagation to measure distance and time yields the same Lorentz invariance as the postulate that the speed of light is the same in all inertial reference frames, the question arises as to what difference there is between the two interpretations of special relativity.
		Lorentz invariance is a property of the wave equation and Lorentz transformations relate measurements in different reference frames whenever wave propagation is used to measure length and time.
	home.att.net /~soliduniverse/Relativity/Relativity.html (3056 words)

	Backreaction: Deformed Special Relativity (Site not responding. Last check: 2007-10-10)
		IIRC the way Lorentz violation is supposed to show up in loopy physics is that the dispersion relation is violated and the speed of light depends on energy (showing up in early or late arrival of ultra high energy gamma ray burst photons compared to ones of lower energy).
		The one invariant is the speed of light, the other one is the regulator in the ultra violet, alias a maximal energy scale.
		DSR is supposed to be constructed as a nonlinear representation of the Lorentz algebra.
	backreaction.blogspot.com /2006/12/deformed-special-relativity.html (7072 words)

	QUANTUM LIGHT CONES (Site not responding. Last check: 2007-10-10)
		To give form to these two ideas, the concept of space-time is born together with the use of the Lorentz transformations of four dimensional vectors ensuring the second postulate.
		In the structure of the Lorentz transformations there is a built in limit for the relative speed given between two inertial frames, the well known fact that no material object can go faster than light not even at the speed of light.
		Lorentz invariance of General relativity for n > 1 vacuum structure,allows superluminal processes ocurring in space-time therefore the fl holes are not fl in this context, and singularities may not occur due to the possibility of emission of large amounts of matter.
	www.meta-religion.com /Physics/Relativity/quantum_light_cones.htm (616 words)

	The Reference Frame: Lorentz violation and deformed special relativity
		One of the topics raised by the recent Joe Polchinski's review that led to some continued discussions is the topic of the hypothetical violations of the Lorentz symmetry and various proposed modifications of special relativity such as the so-called doubly special relativity or deformed special relativity.
		This principle requires that the laws of physics are invariant under a ten-dimensional group, generated by 1 temporal and 3 spatial translations, 3 rotations, and 3 Galilean boosts.
		Various ingredients are modified and you might guess that such a theory will violate many of the previous principles such as the Lorentz invariance of the physical laws or the postulates of quantum mechanics.
	motls.blogspot.com /2006/12/lorentz-violation-and-deformed-special.html (2798 words)

	Quantum Light Cones (Site not responding. Last check: 2007-10-10)
		The speed of the light is constant for any observer regardless of their relative speed in a given quantum state labeled by a quantum number in the transformation law.
		Note that for n=1 the usual Lorentz transformations are recovered with the usual speed light limit defining therefore the light cone as it has been known.
		Therefore the quantum number n reflects the structure of the global vacuum as a superposition of multiple vacua described by the series, setting the equations covariance level according to Lorentz covariance transformations.
	www.angelfire.com /nj/FTLphysics/QCones.html (587 words)

	Research
		One of the most promising avenues of exploration has been the possibility that quantum gravity might violate Lorentz invariance, which is one of the fundamental symmetries of special relativity.
		If Lorentz invariance is violated then astrophysical objects that accelerate particles to extremely high energies (such as the Crab nebula, pictured in the x-ray spectrum) are sensitive to Lorentz violation.
		For list of other astrophysical phenomena that can be used to set limits on Lorentz violation, including the GZK cutoff and active galaxies, see what my collaborators and I affectionately call 'the long paper'.
	lifshitz.ucdavis.edu /~mattingly/research.htm (895 words)

	Lorentz Invariance
		is a scalar, the Klein-Gordon equation is Lorentz invariant.
		Since the Klein-Gordon operator does not change under continuous Lorentz transformations, we can reason that the wave function is multiplied by a factor with absolute value of unity in these transformations.
		invariant under spatial rotations and proper Lorentz transformations, and are invariant (scalar) or change sign (pseudoscalar) under space inversion.
	www.phys.ualberta.ca /~gingrich/phys512/latex2html2/node23.html (177 words)

	Lorentz invariance in loop quantum gravity - Wikipedia, the free encyclopedia
		Global Lorentz invariance is broken in LQG just like it is broken in general relativity (unless one is dealing with Minkowski spacetime, which is one particular solution of the Einstein field equations).
		Mathematically LQG is local gauge theory of the self-dual subgroup of the complexified Lorentz group, which is related to the action of the Lorentz group on Weyl spinors commonly used in elementary particle physics.
		The effect of replacing a Lie algebra by a q-deformed version is that the series of its representations is truncated (in the case of the rotation group, instead of having representations labelled by all half-integral spins, one is left with all representations with total spin j less than some constant).
	en.wikipedia.org /wiki/Lorentz_invariance_in_loop_quantum_gravity (796 words)

	Einstein Makes Extra Dimensions Toe the Line
		A gamma-ray burst, for example, is at such a great distance that the differences in the speeds of photons in the burst, depending on their energy, might be measurable -- as the quantum foam of space may act to slow light which has been traveling to us for billions of years.
		Stecker and Glashow have pointed out that evidence of the annihilation of the highest-energy gamma rays from Mkn 421 and Mkn 501, obtained from direct observations of these objects, demonstrates clearly that Lorentz invariance is alive and well and not being violated.
		If Lorentz invariance were violated, the gamma rays would pass right through the extragalactic infrared fog without being annihilated.
	universe.nasa.gov /press/2003/031216a.html (1208 words)

	NASA - Einstein Makes Extra Dimensions Toe The Line
		Scientists have hoped to find Lorentz invariance violations by studying gamma-rays coming from the farthest reaches of the visible universe, where the quantum foam of space may act to slow light traveling to us for billions of years.
		Stecker and Glashow have pointed out that evidence of the annihilation of the highest-energy gamma-rays, obtained from direct observations of Mkn 421 and Mkn 501, demonstrates clearly that Lorentz invariance is alive and well and not being violated.
		If Lorentz invariance were violated, the gamma-rays would pass right through the extragalactic infrared fog with insufficient energy to cause annihilation.
	www.nasa.gov /home/hqnews/2003/dec/HQ_03413_einstein.html (784 words)

	CiteULike: Lorentz Invariance Violation and its Role in Quantum Gravity Phenomenology (Site not responding. Last check: 2007-10-10)
		Lorentz Invariance Violation and its Role in Quantum Gravity Phenomenology
		Initially it was expected that observable macroscopic effects caused by microscopic violations of Lorentz invariance would necessarily be suppressed by at least one power of the small ratio between the Planck length and macroscopic lengths.
		In normal field theories, radiative corrections in the presence of microscopic Lorentz violation give macroscopic Lorentz violation that is suppressed only by the size of Standard Model couplings, in clear conflict with observation.
	www.citeulike.org /user/NitinCR/article/848999 (349 words)

	Conclusion (Site not responding. Last check: 2007-10-10)
		Although we long ago decided that the physically measurable intervals between the events of spacetime cannot be accurately represented as the distances between the points of a Euclidean metric space, we continue to assume that the topology of the set of spacetime events is (locally) Euclidean.
		This incongruous state of affairs may be due in part to the historical circumstance that Einstein's special relativity was originally viewed as simply an elegant interpretation of the existing Lorentz Ether Theory.
		This is particularly true if a topology more in accord with Lorentz invariance would also help to clarify some of the puzzling phenomena of quantum mechanics.
	www.mathpages.com /rr/conclusion/conclusion.htm (425 words)

	Alan Kostelecky: Background information on Lorentz/CPT violation (Site not responding. Last check: 2007-10-10)
		We have shown in our publications that arbitrary Lorentz and CPT violations are quantitatively described by a theory called the Standard-Model Extension, which is a modification of the usual Standard Model of particle physics and Einstein's theory of gravity, General Relativity.
		Most published suggestions for a theory of Lorentz or CPT violation either have physical features that seem unlikely to be realized in nature or involve radical revisions of conventional quantum field theory, or both.
		The theory suggests that apparent breaking of CPT and Lorentz symmetry might be observable in existing or feasible experiments, and it leads to a general phenomenology for CPT and Lorentz violation at the level of the Standard Model of particle physics and Einstein's theory of gravity, General Relativity.
	www.physics.indiana.edu /~kostelec/faq.html (2448 words)

	Lorentz symmetry stays intact (February 2003) - News - PhysicsWeb
		Lorentz invariance is fundamental to the special theory of relativity and the Standard Model of particle physics.
		The principle of Lorentz invariance states that the result of an experiment is independent of the velocity at which it is performed.
		In 1998, Don Colladay and Alan Kostelecky of Indiana University identified over a hundred co-efficients related to possible violations of Lorentz invariance in a “general” extension to the Standard Model.
	physicsweb.org /article/news/7/2/12 (384 words)

	RAND \| Papers \| Lorentz Invariance in a Gravitational Field.
		This separation suggests an invariance in the gravitational field which is quite similar to the usual Lorentz invariance of electromagnetism.
		The infinitesimal form of the generalized Lorentz transformation is determined by the fact that the three-dimensional geometry remains Euclidian under the transformation.
		The finite form is determined so that the transformations form a group, and the group is found to be the usual Lorentz group.
	www.rand.org /pubs/papers/P4290 (336 words)

	Tim Ashenfelter webpage (Site not responding. Last check: 2007-10-10)
		Maxwell thought that the reason that electromagnetism followed Lorentz invariance and not Galilean invariance was from the properties of the medium in which light propagates (since all waves propagate in some medium).
		In order to save the concept of the aether, it was proposed that the reason for the null result was due to the contraction of length in the direction of the aether's flow and a difference in the time rate in two different locations.
		Einstein used the recently developed Lorentz transformation and the fact that electromagnetism was Lorentz invariant to develop special relativity.
	www.nd.edu /~tashenfe/index.html (938 words)

	PC1672: 1.2 Lorentz invariance
		This relation between the space and time coordinates of an event in the two frames is the Lorentz transformation for observers with relative velocity
		For a Lorentz boost to a frame moving in a general direction, the transformation has a similar form, mixing the coordinate in the boost direction with the time, and leaving the coordinates in perpendicular directions unchanged.
		In terms of this rather strange-looking notation, a Lorentz transformation have exactly the form of a rotation of the four-component vector
	theory.ph.man.ac.uk /~mikeb/lecture/pc167/relativity/lorentz.html (252 words)

	The role of symmetry in fundamental physics -- Gross 93 (25): 14256 -- Proceedings of the National Academy of Sciences
		invariant, the singlet representation of the rotation group.
		For example the lowest energy state, the ground state of the Hydrogen atom is such a rotational invariant singlet state.
		This gauge invariance is, of course, an artificial one, similar to that which we could obtain by introducing into our equations
	www.pnas.org /cgi/content/full/93/25/14256 (2997 words)

	Modern Tests of Lorentz Invariance (Site not responding. Last check: 2007-10-10)
		Motivated by ideas about quantum gravity, a tremendous amount of effort over the past decade has gone into testing Lorentz invariance in various regimes.
		This review summarizes both the theoretical frameworks for tests of Lorentz invariance and experimental advances that have made new high precision tests possible.
		The current constraints on Lorentz violating effects from both terrestrial experiments and astrophysical observations are presented.
	www.univie.ac.at /EMIS/journals/LRG/Articles/lrr-2005-5/title.html (63 words)

	Minkowski spacetime interval's Lorentz invariance
		Assuming that you are familiar with the Lorentz transformation equations themselves (object moving along x):
		Lorentz invariance requires a space-time interval between two events to have the same magnitude from any frame so:
		The rest of the story is the same but this last method was actually used to derive the Lorentz transformation equations in the first place.
	www.physicsforums.com /showthread.php?t=84319 (535 words)

	Imagine the Universe News - 17 December 2003
		Such a fundamental variation in the speed of light, different for photons of different energies, would violate Lorentz invariance, the basic principle of special relativity.
		These collisions result in the destruction of the gamma-ray and infrared photons, as their energy is converted into mass in the form of electrons and positively charged antimatter- electrons (called positrons), according to Einstein's famous formula E=mc
		This energy budget is satisfied for the highest-energy gamma rays from Mkn 501 and Mkn 421 in interacting with infrared photons if both are moving at the well-known speed of light.
	imagine.gsfc.nasa.gov /docs/features/news/17dec03.html (934 words)

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