scholarly journals Quantum-gravity-induced dual lensing and IceCube neutrinos

2017 ◽  
Vol 26 (08) ◽  
pp. 1750076 ◽  
Author(s):  
Giovanni Amelino-Camelia ◽  
Leonardo Barcaroli ◽  
Giacomo D’Amico ◽  
Niccoló Loret ◽  
Giacomo Rosati
Keyword(s):  
Quantum Gravity ◽  
Energy Dependence ◽  
Momentum Space ◽  
Travel Times ◽  
Space Curvature

Momentum-space curvature, which is expected in some approaches to the quantum-gravity problem, can produce dual redshift, a feature which introduces energy dependence of the travel times of ultrarelativistic particles, and dual lensing, a feature which mainly affects the direction of observation of particles. In our recent paper [Phys. Lett. B 761 (2016) 318, arXiv:1605.00496 .], we explored the possibility that dual redshift might be relevant in the analysis of IceCube neutrinos, obtaining results which are preliminarily encouraging. Here, we explore the possibility that also dual lensing might play a role in the analysis of IceCube neutrinos. In doing so, we also investigate issues which are of broader interest, such as the possibility of estimating the contribution by background neutrinos and some noteworthy differences between candidate “early neutrinos” and candidate “late neutrinos”.

scholarly journals Planck-Scale Dual-Curvature Lensing and Spacetime Noncommutativity

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Giovanni Amelino-Camelia ◽  
Leonardo Barcaroli ◽  
Stefano Bianco ◽  
Laura Pensato
Keyword(s):  
Quantum Gravity ◽  
Momentum Space ◽  
Planck Scale ◽  
Neutrino Telescope ◽  
Space Curvature ◽  
Noncommutative Spacetime ◽  
Gray Areas

It was recently realized that Planck-scale momentum-space curvature, which is expected in some approaches to the quantum-gravity problem, can produce dual-curvature lensing, a feature which mainly affects the direction of observation of particles emitted by very distant sources. Several gray areas remain in our understanding of dual-curvature lensing, including the possibility that it might be just a coordinate artifact and the possibility that it might be in some sense a by-product of the better studied dual-curvature redshift. We stress that data reported by the IceCube neutrino telescope should motivate a more vigorous effort of investigation of dual-curvature lensing, and we observe that studies of the recently proposed “ρ-Minkowski noncommutative spacetime” could be valuable from this perspective. Through a dedicated ρ-Minkowski analysis, we show that dual-curvature lensing is not merely a coordinate artifact and that it can be present even in theories without dual-curvature redshift.

scholarly journals Quantum gravity, dynamical phase-space and string theory

2014 ◽  
Vol 23 (12) ◽  
pp. 1442006 ◽  
Author(s):  
Laurent Freidel ◽  
Robert G. Leigh ◽  
Djordje Minic
Keyword(s):  
Quantum Theory ◽  
Phase Space ◽  
String Theory ◽  
Quantum Gravity ◽  
Momentum Space ◽  
Symplectic Geometry ◽  
Complex Geometry ◽  
Hamiltonian Dynamics ◽  
Natural Extension ◽  
Dynamical Phase

In a natural extension of the relativity principle, we speculate that a quantum theory of gravity involves two fundamental scales associated with both dynamical spacetime as well as dynamical momentum space. This view of quantum gravity is explicitly realized in a new formulation of string theory which involves dynamical phase-space and in which spacetime is a derived concept. This formulation naturally unifies symplectic geometry of Hamiltonian dynamics, complex geometry of quantum theory and real geometry of general relativity. The spacetime and momentum space dynamics, and thus dynamical phase-space, is governed by a new version of the renormalization group (RG).

A NEW FORMULATION OF QUANTUM FIELD THEORY ON S4

1994 ◽  
Vol 09 (18) ◽  
pp. 3245-3282 ◽  
Author(s):  
B.A. HARRIS ◽  
G.C. JOSHI
Keyword(s):  
Field Theory ◽  
Angular Momentum ◽  
Quantum Gravity ◽  
Momentum Space ◽  
Space Representation ◽  
Fundamental Constants ◽  
Spherical Space ◽  
Recent Developments ◽  
New Formulation ◽  
Constants Of Nature

Recent developments in quantum gravity suggest that wormholes may influence the observed values of the constants of nature. The Euclidean formulation of quantum gravity predicts that wormholes induce a probability distribution in the space of possible fundamental constants. In particular, the effective action on a large spherical space may lead to the vanishing of the cosmological constant and possibly determine the values of other constants of nature. The ability to perform calculations involving interacting quantum fields, particularly non-Abelian models, on a four-sphere is vital if one is to investigate this possibility. In this paper we present a new formulation of field theory on a four-sphere using the angular momentum space representation of SO(5). We give a review of field theory on a sphere and then show how a matrix element prescription in angular momentum space and a new summation technique based on the complex l plane, overcome previous limitations in calculational techniques. The standard one-loop graphs of QED are given as examples.

scholarly journals RELATIVE LOCALITY IN CURVED SPACETIME

2013 ◽  
Vol 28 (22) ◽  
pp. 1350101 ◽  
Author(s):  
JERZY KOWALSKI-GLIKMAN ◽  
GIACOMO ROSATI
Keyword(s):  
Momentum Space ◽  
Planck Scale ◽  
De Sitter ◽  
Curved Spacetime ◽  
Soccer Ball ◽  
The Core ◽  
Core Feature ◽  
Space Curvature ◽  
Curvature Deformation ◽  
Ball Problem

In this paper we construct the action describing dynamics of the particle moving in curved spacetime, with a nontrivial momentum space geometry. Curved momentum space is the core feature of theories where relative locality effects are present. So far aspects of nonlinearities in momentum space have been studied only for flat or constantly expanding (de Sitter) spacetimes, relying on their maximally symmetric nature. The extension of curved momentum space frameworks to arbitrary spacetime geometries could be relevant for the opportunities to test Planck-scale curvature/deformation of particles momentum space. As a first example of this construction we describe the particle with κ-Poincaré momentum space on a circular orbit in Schwarzschild spacetime, where the contributes of momentum space curvature turn out to be negligible. The analysis of this problem relies crucially on the solution of the soccer ball problem.

scholarly journals BORN'S PROPHECY LEAVES NO SPACE FOR QUANTUM GRAVITY

2012 ◽  
Vol 09 (06) ◽  
pp. 1261001 ◽  
Author(s):  
GIOVANNI AMELINO-CAMELIA
Keyword(s):  
Quantum Gravity ◽  
Momentum Space ◽  
Physical Content ◽  
Emergent Gravity ◽  
Max Born ◽  
Emergent Spacetime

I stress that spacetime is a redundant abstraction, since describing the physical content of all so-called "spacetime measurements" only requires timing (by a physical/material clock) of particle detections (at a physical/material detector). It is interesting then to establish which aspects of our current theories afford us the convenient abstraction of a spacetime. I emphasize the role played by the assumed triviality of the geometry of momentum space, which makes room for an observer-independent notion of locality. This is relevant for some recent studies of the quantum-gravity problem that stumbled upon hints of a nontrivial geometry of momentum space, something which had been strikingly envisaged for quantum gravity already in 1938 by Max Born. If indeed momentum space has nontrivial geometry then the abstraction of a spacetime becomes more evidently redundant and less convenient: one may still abstract a spacetime but only allowing for the possibility of a relativity of spacetime locality. I also provide some examples of how all this could affect our attitude toward the quantum-gravity problem, including some for the program of emergent gravity and emergent spacetime. And in order to give an illustrative example of possible logical path for the "disappearance of spacetime" I rely on formulas inspired by the κ-Poincaré framework.

scholarly journals Limits to Quantum Gravity Effects on Energy Dependence of the Speed of Light from Observations of TeV Flares in Active Galaxies

1999 ◽  
Vol 83 (11) ◽  
pp. 2108-2111 ◽  
Author(s):  
S. D. Biller ◽  
A. C. Breslin ◽  
J. Buckley ◽  
M. Catanese ◽  
M. Carson ◽  
...  
Keyword(s):  
Quantum Gravity ◽  
Energy Dependence ◽  
Active Galaxies ◽  
Speed Of Light ◽  
Gravity Effects

scholarly journals UV AND IR QUANTUM-SPACETIME EFFECTS FOR THE CHANDRASEKHAR MODEL

2012 ◽  
Vol 21 (06) ◽  
pp. 1250052 ◽  
Author(s):  
GIOVANNI AMELINO-CAMELIA ◽  
NICCOLÒ LORET ◽  
GIANLUCA MANDANICI ◽  
FLAVIO MERCATI
Keyword(s):  
Quantum Gravity ◽  
Momentum Space ◽  
White Dwarfs ◽  
High Energy ◽  
The Sun ◽  
Planck Length ◽  
High Energies ◽  
Quantum Spacetime

We modify the Chandrasekhar model of white dwarfs by introducing some of the momentum-space features which have been considered in the quantum-gravity literature. We find that when the new effects are confined to high energies, one only finds significant corrections to the Chandrasekhar model in regimes where the model anyway lacks any contact with observations. But these high-energy effects could play an important role in cases where ultra-high densities are present, even when the relevant star is still gigantic in Planck-length units. If the effects are not confined to high energies, as a result of "ultraviolet/infrared mixing", there could be significant implications for white dwarfs whose mass is roughly half the mass of the Sun, some of which are described in the literature as "strange white dwarfs".

scholarly journals LIVING IN CURVED MOMENTUM SPACE

2013 ◽  
Vol 28 (12) ◽  
pp. 1330014 ◽  
Author(s):  
JERZY KOWALSKI-GLIKMAN
Keyword(s):  
Quantum Gravity ◽  
Momentum Space ◽  
Degrees Of Freedom ◽  
Space Time ◽  
Topological Phase ◽  
De Sitter ◽  
Interacting Particles ◽  
Detailed Review ◽  
Theory Of Gravity ◽  
Relativistic Particles

In this paper, we review some aspects of relativistic particles' mechanics in the case of a nontrivial geometry of momentum space. We start by showing how the curved momentum space arises in the theory of gravity in 2+1 dimensions coupled to particles, when (topological) degrees of freedom of gravity are solved for. We argue that there might exist a similar topological phase of quantum gravity in 3+1 dimensions. Then, we characterize the main properties of the theory of interacting particles with curved momentum space and the symmetries of the action. We discuss the space–time picture and the emergence of the principle of relative locality, according to which locality of events is not absolute but becomes observer dependent, in the controllable, relativistic way. We conclude with the detailed review of the most studied κ-Poincaré framework, which corresponds to the de Sitter momentum space.

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