Papers by David Mattingly
International Journal of Modern Physics D, 2009
We investigate the consequences of higher dimension Lorentz violating, CPT even kinetic operators... more We investigate the consequences of higher dimension Lorentz violating, CPT even kinetic operators that couple standard model fields to a non-zero vector field in an Effective Field Theory framework. Comparing the ultra-high energy cosmic ray spectrum reconstructed in the presence of such terms with data from the Pierre Auger Observatory allows us to establish stringent bounds on O(E/MPl)2 suppressed violations
Springer Proceedings in Physics, 2005
In most fields of physics it goes without saying that observation and prediction play a central r... more In most fields of physics it goes without saying that observation and prediction play a central role, but unfortunately quantum gravity (QG) has so far not fit that mold. Many intriguing and ingenious ideas have been explored, but it seems safe to say that without both observing phenomena that depend on QG, and extracting reliable predictions from candidate theories that can be compared with observations, the goal of a theory capable of incorporating quantum mechanics and general relativity will remain unattainable.
Physical Review D, 2006
In the causal set approach to quantum gravity, Poincaré symmetry is modified by swerving in space... more In the causal set approach to quantum gravity, Poincaré symmetry is modified by swerving in spacetime, induced by the random lattice discretization of the space-time structure. The broken translational symmetry at short distances is argued to lead to a residual diffusion in momentum space, whereby a particle can acquire energy and momentum by drift along its mass shell and a system in equilibrium can spontaneously heat up. We consider bounds on the rate of momentum space diffusion coming from astrophysical molecular clouds, nuclear stability and cosmological neutrino background. We find that the strongest limits come from relic neutrinos, which we estimate to constrain the momentum space diffusion constant by k < 10 −61 GeV 3 for neutrinos with masses mν > 0.01 eV, improving the previously quoted bounds by roughly 17 orders of magnitude.
Deserfest - A Celebration of the Life and Works of Stanley Deser, 2006
International Journal of Modern Physics D, 2014
Physical Review Letters, 2013
Holography grew out of black hole thermodynamics, which relies on the causal structure and genera... more Holography grew out of black hole thermodynamics, which relies on the causal structure and general covariance of general relativity. In Einstein-aether theory, a generally covariant theory with a dynamical timelike unit vector, every solution breaks local Lorentz invariance, thereby grossly modifying the causal structure of gravity. However, there are still absolute causal boundaries, called "universal horizons", which are not Killing horizons yet obey a first law of black hole mechanics and must have an entropy if they do not violate a generalized second law. We couple a scalar field to the timelike vector and show via the tunneling approach that the universal horizon radiates as a blackbody at a fixed temperature, even if the scalar field equations also violate local Lorentz invariance. This suggests that the class of holographic theories may be much broader than currently assumed.
Physical Review D, 2010
Assuming the hoop conjecture in classical general relativity and quantum mechanics, any observer ... more Assuming the hoop conjecture in classical general relativity and quantum mechanics, any observer who attempts to perform an experiment in an arbitrarily small region will be stymied by the formation of a black hole within the spatial domain of the experiment. This behavior is often invoked in arguments for a fundamental minimum length. Extending a proof of the hoop conjecture for spherical symmetry to include higher curvature terms we investigate this minimum length argument when the gravitational couplings run with energy in the manner predicted by asymptotically safe gravity. We show that argument for the mandatory formation of a black hole within the domain of an experiment fails. Neither is there a proof that a black hole doesn't form. Instead, whether or not an observer can perform measurements in arbitrarily small regions depends on the specific numerical values of the couplings near the UV fixed point. We further argue that when an experiment is localized on a scale much smaller than the Planck length, at least one enshrouding horizon must form outside the domain of the experiment. This implies that while an observer may still be able to perform local experiments, communicating any information out to infinity is prevented by a large horizon surrounding it, and thus compatibility with general relativity can still be restored in the infrared limit.
Physical Review D, 2008
Many of the most important astrophysical tests of Lorentz symmetry also assume that energymomentu... more Many of the most important astrophysical tests of Lorentz symmetry also assume that energymomentum of the observed particles is exactly conserved. In the causal set approach to quantum gravity a particular kind of Lorentz symmetry holds but energy-momentum conservation may be violated. We show that incorrectly assuming exact conservation can give rise to a spurious signal of Lorentz symmetry violation for a causal set. However, the size of this spurious signal is much smaller than can be currently detected and hence astrophysical Lorentz symmetry tests as currently performed are safe from causal set induced violations of energy-momentum conservation.
Physical Review D, 2012
Modified gravity models such as Hořava-Lifshitz gravity or Einstein-aether theory violate local L... more Modified gravity models such as Hořava-Lifshitz gravity or Einstein-aether theory violate local Lorentz invariance and therefore destroy the notion of a universal light cone. Despite this, in the infrared limit both models above possess static, spherically symmetric solutions with "universal horizons" -hypersurfaces that are causal boundaries between an interior region and asymptotic spatial infinity. In other words, there still exist black hole solutions. We construct a Smarr formula (the relationship between the total energy of the spacetime and the area of the horizon) for such a horizon in Einstein-aether theory. We further show that a slightly modified first law of black hole mechanics still holds with the relevant area now a cross-section of the universal horizon. We construct new analytic solutions for certain Einstein-aether Lagrangians and illustrate how our results work in these exact cases. Our results suggest that holography may be extended to these theories despite the very different causal structure as long as the universal horizon remains the unique causal boundary when matter fields are added.
Physical Review D, 1999
1 The fact that redshifting plays no role in producing the stringy Hawking radiation is presumabl... more 1 The fact that redshifting plays no role in producing the stringy Hawking radiation is presumably tied to the fact that the string calculations apply in the "near-extremal" limit that the surface gravity tends to zero.
Physical Review D, 2001
Short distance structure of spacetime may show up in the form of high frequency dispersion. Altho... more Short distance structure of spacetime may show up in the form of high frequency dispersion. Although such dispersion is not locally Lorentz invariant, we show in a scalar field model how it can nevertheless be incorporated into a generally covariant metric theory of gravity provided the locally preferred frame is dynamical. We evaluate the resulting energy-momentum tensor and compute its expectation value for a quantum field in a thermal state. The equation of state differs at high temperatures from the usual one, but not by enough to impact the problems of a hot big bang cosmology. We show that a superluminal dispersion relation can solve the horizon problem via superluminal equilibration, however it cannot do so while remaining outside the Planck regime unless the dispersion relation is artificially chosen to have a rather steep dependence on wavevector.
Physical Review D, 2001
We study a generally covariant model in which local Lorentz invariance is broken by a dynamical u... more We study a generally covariant model in which local Lorentz invariance is broken by a dynamical unit timelike vector field u a -the "aether". Such a model makes it possible to study the gravitational and cosmological consequences of preferred frame effects, such as "variable speed of light" or high frequency dispersion, while preserving a generally covariant metric theory of gravity. In this paper we restrict attention to an action for an effective theory of the aether which involves only the antisymmetrized derivative ∇ [a u b] . Without matter this theory is equivalent to a sector of the Einstein-Maxwell-charged dust system. The aether has two massless transverse excitations, and the solutions of the model include all vacuum solutions of general relativity (as well as other solutions). However, the aether generally develops gradient singularities which signal a breakdown of this effective theory. Including the symmetrized derivative in the action for the aether field may cure this problem.
Living Reviews in Relativity, 2005
Motivated by ideas about quantum gravity, a tremendous amount of effort over the past decade has ... more 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.
Journal of Physics: Conference Series, 2013
Journal of Physics: Conference Series, 2013
Journal of Cosmology and Astroparticle Physics, 2010
We study, within an effective field theory framework, O(E 2 /M 2 Pl ) Planckscale suppressed Lore... more We study, within an effective field theory framework, O(E 2 /M 2 Pl ) Planckscale suppressed Lorentz invariance violation (LV) effects in the neutrino sector, whose size we parameterize by a dimensionless parameter η ν . We find deviations from predictions of Lorentz invariant physics in the cosmogenic neutrino spectrum. For positive O(1) coefficients no neutrino will survive above 10 19 eV. The existence of this cutoff generates a bump in the neutrino spectrum at energies of 10 17 eV. Although at present no constraint can be cast, as current experiments do not have enough sensitivity to detect ultra-high-energy neutrinos, we show that experiments in construction or being planned have the potential to cast limits as strong as η ν 10 −4 on the neutrino LV parameter, depending on how LV is distributed among neutrino mass states. Constraints on η ν < 0 can in principle be obtained with this strategy, but they require a more detailed modeling of how LV affects the neutrino sector.
Journal of Cosmology and Astroparticle Physics, 2013
Recently there has been a renewed activity in the physics of violations of Lorentz invariance in ... more Recently there has been a renewed activity in the physics of violations of Lorentz invariance in the neutrino sector. Flavor dependent Lorentz violation, which generically changes the pattern of neutrino oscillations, is extremely tightly constrained by oscillation experiments. Flavor independent Lorentz violation, which does not introduce new oscillation phenomena, is much more weakly constrained with constraints coming from time of flight and anomalous threshold analyses. We use a simplified rotationally invariant model to investigate the effects of finite baselines and energy dependent dispersion on anomalous reaction rates in long baseline experiments and show numerically that anomalous reactions do not necessarily cut off the spectrum quite as sharply as currently assumed. We also present a revised analysis of how anomalous reactions can be used to cast constraints from the observed atmospheric high energy neutrinos and the expected cosmogenic ones.
Physical Review D, 2001
We study a generally covariant model in which local Lorentz invariance is broken "spontaneously" ... more We study a generally covariant model in which local Lorentz invariance is broken "spontaneously" by a dynamical unit timelike vector field $u^a$---the "aether". Such a model makes it possible to study the gravitational and cosmological consequences of preferred frame effects, such as ``variable speed of light" or high frequency dispersion, while preserving a generally covariant metric theory of gravity. In this paper we restrict attention to an action for an effective theory of the aether which involves only the antisymmetrized derivative $\nabla_{[a}u_{b]}$. Without matter this theory is equivalent to a sector of the Einstein-Maxwell-charged dust system. The aether has two massless transverse excitations, and the solutions of the model include all vacuum solutions of general relativity (as well as other solutions). However, the aether generally develops gradient singularities which signal a breakdown of this effective theory. Including the symmetrized derivative in the action for the aether field may cure this problem.
Classical and Quantum Gravity, 2005
In this article we analyze the radiation loss from a high energy cosmic ray proton propagating in... more In this article we analyze the radiation loss from a high energy cosmic ray proton propagating in a spacetime with non-systematic Lorentz violation. From an effective field theory perspective we illuminate flaws in previous attempts that use threshold approaches to analyze this problem. We argue that in general such approaches are of rather limited use when dealing with non-systematic Lorentz violating scenarios. The main issues we raise are a) the limited applicability of threshold energy conservation rules when translation invariance is broken and b) the large amounts of proton particle production due to the time dependence of the fluctuations. Ignoring particle production, we derive a constraint on the magnitude of velocity fluctuation |v f | < 10 −6.5 , much weaker than has been previously argued. However, we show that in fact particle production makes any such constraint completely unreliable. ‡ email: [email protected] § An effective field theory of course yields particle dispersion relations. However, often a dispersion modification alone is studied without explicitly working in a particular field theory.
Physical Review D, 2002
We analyze observational constraints from TeV astrophysics on Lorentz violating nonlinear dispers... more We analyze observational constraints from TeV astrophysics on Lorentz violating nonlinear dispersion for photons and electrons without assuming any a priori equality between the photon and electron parameters. The constraints arise from thresholds for vacuum Cerenkov radiation, photon decay and photo-production of electron-positron pairs. We show that the parameter plane for cubic momentum terms in the dispersion relations is constrained to an order unity region in Planck units. We find that the threshold configuration can occur with an asymmetric distribution of momentum for pair creation, and with a hard photon for vacuum Cerenkov radiation.
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Papers by David Mattingly