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Douglas M. Gingrich

Publications and source records attributed to Douglas M. Gingrich.

At least 19 recordsLinked to original sources
arXiv2026

Canonical form of a deformed Poisson bracket spacetime

The general uncertainty principle applied to gravity can be implemented as a set of modified Poisson brackets in the canonical formalism. As such, the theory is not canonical and the resulting equations of motion do not lead to a covariant metric. We construct a Hamiltonian that when applying the usual canonical formalism gives a closed algebra and equations of motion that result in the original metric obtained by using distorted Poisson brackets. The resulting theory is thus rendered canonical and covariant. We then covariantly couple scalar matter and dust to the modified gravity to allow the study of dynamics.

gr-qc↗
arXiv2026

Dust collapse and bounce in spherically symmetric quantum-inspired gravity models

We develop an algebraic equation to describe the collapse and possible bounce of dust in quantum-inspired gravity models with spherical symmetry from knowledge of the vacuum solution. Starting from a wide class of spherically symmetric spacetimes, we write down the covariant Hamiltonian constraints that under dynamical flow give rise to metrics of many spherically symmetric gravity models. The constraint equations are solved for the Hamiltonian evolution and simple equations for the location of the outer boundary of the dust versus time and the apparent horizons in terms of metric shape functions are obtained. The dust density is not assumed to be homogeneous inside the collapsing ball. Using the developed algebraic equations, we examine several quantum-inspired gravity metrics to obtain bounce results either previously obtained by different methods or new results.

gr-qc↗
arXiv2025

Geometry of a generalized uncertainty-inspired spacetime

We examine the geometry of a generalized uncertainty-inspired quantum black hole. The diagonal line element is not $t$-$r$ symmetric, i.e. $g_{00} \ne -1/g_{11}$, which leads to an interesting approach to resolving the classical curvature singularity. In this paper, we show, in Schwarzschild coordinates, the $r = 0$ coordinate location is a null surface which is not a transition surface or leads to a black bounce. We find the expansion of null geodesic congruences in the interior turn around then vanishes at $r = 0$, and the energy conditions are predominately violated indicating a repulsive gravitational core. In addition, we show that the line element admits a wormhole solution which is not traversable, and the black hole at its vanishing horizon radius could be interpreted as a remnant.

gr-qc↗
arXiv2024

A generalized uncertainty-inspired quantum black hole

We derive the full spacetime metric of a generalized uncertainty-inspired quantum black hole. We examine a previous model of the interior in this approach and show that extending its metric to the full spacetime leads to serious issues in the asymptotic region. To remedy this, we introduce an ``improved scheme'' mimicking a similar prescription used in loop quantum gravity, where the quantum parameters are made momentum-dependent. Under this scheme, we rework the interior of the black hole and extend it to the full spacetime. We find that the resulting metric is asymptotically flat and its associated Kretschmann scalar is regular everywhere. We also show that the null expansion and Raychaudhuri equation are regular everywhere in this spacetime, implying that the classical singularity is resolved.

gr-qc↗
arXiv2024

Quasinormal modes of a nonsingular spherically symmetric black hole effective model with holonomy corrections

We calculate the quasinormal modes of a nonsingular spherically symmetric black hole effective model with holonomy corrections. The model is based on quantum corrections inspired by loop quantum gravity. It is covariant and results in a spacetime that is regular everywhere with a parameter-dependent black bounce. Perturbations of these black holes due to massless scalar and electromagnetic fields have been previously calculated and some intriguing results were observed. For some modes, the frequency versus minimum-radius parameter trajectories were found to spiral and self-intersect in the complex plane. In addition, the spectrum of overtones has real frequencies that oscillate with increasing overtone number, and may even vanish for some overtones. We have calculated the quasinormal modes for all massless spin perturbations, including spin-1/2, and axial- and polar-gravitational. We find that the trajectory-spirals are restricted to scalar perturbations and observe some interesting overtone behaviour for gravitational perturbations. The amount of isospectrality violation in the gravitational quasinormal mode spectra is also examined.

gr-qc↗
arXiv2023

Quasinormal modes of loop quantum black holes near the Planck scale

We compare four loop quantum gravity inspired black hole metrics near the Planck scale. Spin 0, 1/2, 1, and 2 field perturbations on these backgrounds are studied. The axial gravitational quasinormal modes are calculated and compared. The time evolution of the ringdown is examined. We also calculate the quasinormal modes in the eikonal limit and compare with the predictions from circular null geodesics.

gr-qc↗
arXiv2023

Greybody factors for higher-dimensional non-commutative geometry inspired black holes

Greybody factors are computed for massless fields of spin 0, 1/2, 1, and 2 emitted from higher-dimensional non-commutative geometry inspired black holes. Short-range potentials are used with path-ordered matrix exponentials to numerically calculate transmission coefficients. The resulting absorption cross sections and emission spectra are computed on the brane and compared with the higher-dimensional Schwarzschild-Tangherlini black hole. A non-commutative black hole at its maximum temperature in seven extra dimensions will radiate a particle flux and power of 0.72-0.81 and 0.75-0.81, respectively, times lower than a Schwarzschild-Tangherlini black hole of the same temperature. A non-commutative black hole at its maximum temperature in seven extra dimensions will radiate a particle flux and power of 0.64-0.72 and 0.60-0.64, respectively, times lower than a Schwarzschild-Tangherlini black hole of the same mass.

gr-qc↗
arXiv2023

Quantum atmosphere effective radii for different spin fields from quantum gravity inspired black holes

Quantum atmosphere effective radii for the emission of spin-0, -1/2, -1, and -2 massless fields from Schwarzschild, Tangherlini, non-commutative geometry inspired, and polymeric black holes are calculated. The power observed from the black hole at spatial infinity taking greybody factors into account is compared to an equal-power black-body radiator of the same temperature but different effective radius. A large range of different radii are obtained for different spin fields and black holes. The equal-power black-body effective radius is not, in general, a good proxy for the location of the quantum atmosphere.

gr-qc↗
arXiv2020

Quantum black holes in the horizon quantum mechanics model at the Large Hadron Collider

Quantum black hole production at the Large Hadron Collider is investigated using the horizon quantum mechanics model. This model has novel implications for how black holes might be observed in collider experiments. Black hole production is predicted to be possible below the Planck scale, thus leading to the intriguing possibility that black holes could be produced even if the Planck scale is slightly above the collider centre of mass energy. In addition, the usual anticipated resonance in the black hole mass distribution is significantly widened in this model. For values of the Planck scale above the current lower limits, the shape of the black hole mass distribution is almost independent of the Planck scale and depends more on the number of extra dimensions. These model features suggest the need for alternative search strategies in collider experiments.

hep-ph↗
arXiv2018

Monte Carlo event generator for the production and decay of string resonances in proton-proton collisions

We describe a Monte Carlo event generator for the production and decay of first and second string resonances through 2 $\rightarrow$ 2 partonic and also 2-parton $\rightarrow$ $γ$-parton scatterings in proton-proton collisions - STRINGS version 1.00. This generator is also capable of producing QCD diparton processes. STRINGS is written in Python 2 and can be interfaced to common hadronization programs using the Les Houches Accord.

hep-ph↗
arXiv2015

Collider searches for non-perturbative low-scale gravity states

The possibility of producing non-perturbative low-scale gravity states in collider experiments was first discussed in about 1998. The ATLAS and CMS experiments have searched for non-perturbative low-scale gravity states using the Large Hadron Collider (LHC) with a proton--proton centre of mass energy of 8 TeV. These experiments have now seriously confronted the possibility of producing non-perturbative low-scale gravity states which were proposed over 17 years ago. I will summarise the results of the searches, give a personal view of what they mean, and make some predictions for 13 TeV centre of mass energy. I will also discuss early ATLAS 13 TeV centre of mass energy results.

hep-ph↗
arXiv2012

Model uncertainties on limits for quantum black hole production in dijet events from ATLAS

We study the model uncertainties on limits for quantum black hole production in dijet events from ATLAS. For models that assume a hard-disk cross section, the model uncertainty on the threshold mass limits is about 5%. If the trapped surface calculation is used for the cross section, the ATLAS mass threshold limits are below 2 TeV for all number of dimensions. Using the ATLAS data in the context of the Randall-Sundrum type-1 model gives a threshold mass lower limit of 2.84 TeV.

hep-ph↗
arXiv2011

Exotic Searches at ATLAS

We present the first results of searches for new physics with the ATLAS detector using the 2010 Large Hadron Collider proton-proton collision data at a centre of mass energy of 7 TeV. After a few months of operation, these searches already go beyond the reach of previous experiments, and start to explore new territories.

hep-ex↗
arXiv2010

Quantum black holes with charge, colour, and spin at the LHC

In low-scale gravity scenarios, quantum black holes could be produced at the Large Hadron Collider (LHC) provided the Planck scale is not higher than a few TeV. Based on fundamental principles and a few basic assumptions, we have constructed a model for quantum black hole production and decay in proton-proton collisions. By performing a detailed particle-level simulation at LHC energies, we have estimated cross sections and branching fractions for final-state particle topologies that would uniquely identify quantum black holes in LHC detectors. If the Planck scale is about a TeV, even with the most pessimistic assumptions, the rates for quantum black hole production are estimated to be above backgrounds, and some of the final-particle states are not found in Standard Model processes. Our results could form the starting point for a detailed investigation of quantum black holes by the LHC experiments.

hep-ph↗
arXiv2010

Noncommutative geometry inspired black holes in higher dimensions at the LHC

When embedding models of noncommutative geometry inspired black holes into the peridium of large extra dimensions, it is natural to relate the noncommutativity scale to the higher-dimensional Planck scale. If the Planck scale is of the order of a TeV, noncommutative geometry inspired black holes could become accessible to experiments. In this paper, we present a detailed phenomenological study of the production and decay of these black holes at the Large Hadron Collider (LHC). Noncommutative inspired black holes are relatively cold and can be well described by the microcanonical ensemble during their entire decay. One of the main consequences of the model is the existence of a black hole remnant. The mass of the black hole remnant increases with decreasing mass scale associated with noncommutative and decreasing number of dimensions. The experimental signatures could be quite different from previous studies of black holes and remnants at the LHC since the mass of the remnant could be well above the Planck scale. Although the black hole remnant can be very heavy, and perhaps even charged, it could result in very little activity in the central detectors of the LHC experiments, when compared to the usual anticipated black hole signatures. If this type of noncommutative inspired black hole can be produced and detected, it would result in an additional mass threshold above the Planck scale at which new physics occurs.

hep-ph↗
arXiv2010

Production of tidal-charged black holes at the Large Hadron Collider

Tidal-charged black hole solutions localized on a three-brane in the five-dimensional gravity scenario of Randall and Sundrum have been known for some time. The solutions have been used to study the decay, and growth, of black holes with initial mass of about 10 TeV. These studies are interesting in that certain black holes, if produced at the Large Hadron Collider, could live long enough to leave the detectors. I examine the production of tidal-charged black holes at the Large Hadron Collider and show that it is very unlikely that they will be produced during the lifetime of the accelerator.

hep-ph↗