A5061414527- Noncommutative and Quantum Gravity Theories
- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Quantum Mechanics and Applications
- Relativity and Gravitational Theory
- Neutrino Physics Research
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Mechanical and Optical Resonators
- Advanced Differential Geometry Research
- Astrophysics and Cosmic Phenomena
- Astro and Planetary Science
- Quantum Information and Cryptography
- Planetary Science and Exploration
- Pulsars and Gravitational Waves Research
- Dark Matter and Cosmic Phenomena
- Mathematical and Theoretical Analysis
- Spacecraft and Cryogenic Technologies
- Advanced Numerical Analysis Techniques
- Astrophysical Phenomena and Observations
- Advanced Mathematical Theories and Applications
- Sustainable Building Design and Assessment
- Quantum Electrodynamics and Casimir Effect
- Orbital Angular Momentum in Optics
- Housing Market and Economics
University of New Hampshire
2013-2024
Istituto Nazionale di Fisica Nucleare
2022
University of L'Aquila
2022
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Gran Sasso
2022
University of Nottingham
2014
University of New Hampshire at Manchester
2008-2014
Max Planck Institute for Nuclear Physics
2009
University of California, Davis
2005-2006
University of California System
2005
University of Maryland, College Park
1999-2004
We study a generally covariant model in which local Lorentz invariance is broken "spontaneously" by dynamical unit timelike vector field $u^a$---the "aether". Such makes it possible to the gravitational and cosmological consequences of preferred frame effects, such as ``variable speed light" or high frequency dispersion, while preserving metric theory gravity. In this paper we restrict attention an action for effective aether involves only antisymmetrized derivative $\nabla_{[a}u_{b]}$....
Local Lorentz invariance violation can be realized by introducing extra tensor fields in the action that couple to matter. If is rotationally invariant some frame, then it characterized an ``aether,'' i.e., a unit timelike vector field. General covariance requires aether field dynamical. In this paper we study linearized theory of such coupled gravity and find speeds polarizations all wave modes terms four constants appearing most general at second order derivatives. We addition usual two...
The exploration of the universe has recently entered a new era thanks to multi-messenger paradigm, characterized by continuous increase in quantity and quality experimental data that is obtained detection various cosmic messengers (photons, neutrinos, rays gravitational waves) from numerous origins. They give us information about their sources properties intergalactic medium. Moreover, astronomy opens up possibility search for phenomenological signatures quantum gravity. On one hand, most...
Recent work has shown that dispersion relations with Planck scale Lorentz violation can produce observable effects at energies many orders of magnitude below the energy M. This opens a window on physics may reveal quantum gravity phenomena. It already constrained possibility violation, which is suggested by some approaches to gravity. In this we carry out systematic analysis reaction thresholds, allowing unequal deformation parameters for different particle relations. The thresholds are...
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 electron parameters. The arise thresholds vacuum Cerenkov radiation, decay photo-production of electron-positron pairs. show that parameter plane cubic momentum terms in relations is constrained to an order unity region Planck units. find threshold configuration can occur with asymmetric distribution pair...
Constraints on possible Lorentz symmetry violation (LV) of order $E/{M}_{\mathrm{P}\mathrm{l}\mathrm{a}\mathrm{n}\mathrm{c}\mathrm{k}}$ for electrons and photons in the framework effective field theory (EFT) are discussed. Using (i) report polarized MeV emission from GRB021206 (ii) absence vacuum \ifmmode \check{C}\else \v{C}\fi{}erenkov radiation synchrotron Crab Nebula, we improve previous bounds by ${10}^{\ensuremath{-}10}$ ${10}^{\ensuremath{-}2}$, respectively. We also show that LV...
Modified gravity models such as Ho\ifmmode \check{r}\else \v{r}\fi{}ava-Lifshitz or Einstein-\ae{}ther theory violate local Lorentz invariance and therefore destroy the notion of a universal light cone. Despite this, in infrared limit both above possess static, spherically symmetric solutions with ``universal horizons''---hypersurfaces that are causal boundaries between an interior region asymptotic spatial infinity. In other words, there still exist black hole solutions. We construct Smarr...
Holography grew out of black hole thermodynamics, which relies on the causal structure and general covariance relativity. In Einstein-æther theory, a generally covariant theory with dynamical timelike unit vector, every solution breaks local Lorentz invariance, thereby grossly modifying gravity. However, there are still absolute boundaries, called "universal horizons," not Killing horizons yet obey first law mechanics must have an entropy if they do violate generalized second law. We couple...
High energy cosmic neutrino observations provide a sensitive test of Lorentz invariance violation, which may be consequence quantum gravity theories. We consider class non-renormalizable, violating operators that arise in an effective field theory description violation the sector inspired by Planck-scale physics and models. assume conservative generic scenario for redshift distribution extragalactic sources employ Monte Carlo techniques to describe superluminal propagation, treating...
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 ultra-high energy cosmic ray spectrum reconstructed presence such terms with data from Pierre Auger observatory allows us establish two sided bounds on coefficients mass five and six for proton pion. Our imply both protons pions, scale symmetry breaking must be well above Planck scale....
Local information objectivity, that local observers can infer the same about a model upon exchange of experimental data, is fundamental to science. It mathematically encoded via Cencov's theorem: Fisher metric unique invariant under sufficient statistics. However, quantum gravity typically violates some Cencov assumptions, allowing and Born rule vary between observers. We explain these violations, possible tests, new approach based on generally covariant geometry.
Short distance structure of spacetime may show up in the form high frequency dispersion. Although such dispersion is not locally Lorentz invariant, we a scalar field model how it can nevertheless be incorporated into generally covariant metric theory gravity provided preferred frame dynamical. We evaluate resulting energy-momentum tensor and compute its expectation value for quantum thermal state. The equation state differs at temperatures from usual one, but by enough to impact problems hot...
Recently we have discussed a new approach to the problem of quantum gravity in which mechanical structures that are traditionally fixed, such as Fubini-Study metric Hilbert space states, become dynamical and so implement idea gravitizing quantum. In this paper elaborate on specific test using triple interference varying gravitational field. Our discussion is driven by profound analogy with recent triple-path experiments performed context non-linear optics. We emphasize experiment field would...
We review the status of "Einstein-Aether theory", a generally covariant theory gravity coupled to dynamical, unit timelike vector field that breaks local Lorentz symmetry. Aspects waves, stars, black holes, and cosmology are discussed, together with theoretical observational constraints. Open questions stressed.
Universal horizons in Ho\v{r}ava-Lifshitz gravity and Einstein-{\ae}ther theory are the equivalent of causal general relativity appear to have many same properties, including a first law horizon thermodynamics thermal radiation. Since universal infrared solutions putative power counting renormalizable quantum gravitational theory, fully understanding their will shed light on interplay between black hole gravity. In this paper, we provide complete classification, asymptotic charges, all four...
We discuss a new approach to the problem of quantum gravity in which mechanical structures that are traditionally fixed, such as Fubini-Study metric Hilbert space states, become dynamical and so implement idea gravitizing quantum. In particular, this formulation geometry is still consistent with principles unitarity also captures fundamental aspects (quantum) gravity, topology change. Furthermore, we address specific ways testing by utilizing multi-path interference optical lattice atomic clocks.
A general characterization of lower and upper threshold configurations for two particle reactions is determined under the assumptions that single dispersion relations E(p) are rotationally invariant monotonic in p, energy momentum conserved additive multiple particles. It found at a final momenta always parallel initial anti-parallel. The occurrence new phenomena not occurring Lorentz setting, such as thresholds asymmetric pair production thresholds, explained, an illustrative example given.
Scalar field theory on a lattice falling freely into 1+1 dimensional black hole is studied using both WKB and numerical approaches. The outgoing modes are shown to arise from incoming by process analogous Bloch oscillation, with an admixture of negative frequency corresponding the Hawking radiation. Numerical calculations show that effect reproduced within 0.5% whose proper spacing where wavepacket turns around at horizon $\sim0.08$ in units surface gravity 1.
We study, within an effective field theory framework, $O(E^{2}/\Mpl^{2})$ Planck-scale suppressed Lorentz invariance violation (LV) effects in the neutrino sector, whose size we parameterize by a dimensionless parameter $\eta_{\nu}$. find deviations from predictions of invariant physics cosmogenic spectrum. For positive O(1) coefficients no will survive above $10^{19} \eV$. The existence this cutoff generates bump spectrum at energies $10^{17} Although present constraint can be cast, as...