Quantum Gravity Phenomenology  

In General > s.a. approaches; effective theories; quantum gravity [including philosophy] and canonical quantum gravity; quantum spacetime.
* Idea: The identification of quantum properties of spacetime which might give rise to observably large effects.
* Types and examples: Theoretically, some predictions are geometric (like black hole area quantization, with Amin 4 ln2 lP2), others concern behavior of matter (like photon propagation); Phenomenologically, some predict systematic shifts in observed quantities, others new fundamental uncertanties.
* Scale: 1996, Bound is 10–19 m, from p-pbar collisions at Fermilab (no internal structure in quarks at that level), and p decay experiments have in effect probed smaller scales [@ news pn(96)dec].
@ I/II: Amelino-Camelia pw(03)nov; Smolin PT(06)nov.
@ Reviews: Amelino-Camelia MPLA(02)gq-in, a0806.
@ General references: Wheeler IJMPA(93); Salopek IJMPD(94); Smolin gq/95; Ashtekar PRL(96)gq [large effects]; Ahluwalia ChJP(97)gq [non-locality, free-fall, etc]; Amelino-Camelia MPLA(98)gq, LNP(00)gq/99-in, Nat(01)gq, ap/02-in [gamma- and cosmic rays], et al APP(03)gq/02 [particle production]; Ashtekar mp/02-in; Ahluwalia MPLA(02)gq-in; Ng MPLA(03)gq, gq/04-in, NCB(05); Giulini et al ed-03; Amelino-Camelia GRG(04)ap/03 [in space], gq/04-in, et al gq/05-in [strategy]; Aloisio et al gq/04-in, NCB(05)ap-in; Kimberly & Magueijo gq/05-ln; Corichi & Sudarsky IJMPD(05)gq [new scheme]; Ahluwalia-Khalilova CQG(05)ht; Sudarsky IJMPD(05)gq; Smolin gq/06-in; Hossenfelder ht/06-in; Ivanov a0706-in [low-energy]; Amelino-Camelia & Kowalski-Glikman ed-05 [astrophysics and cosmology].
@ Scale: Ne'eman PLA(94) [mass and localizability]; Scardigli NPPS(00)ht/99 [GUT scales]; Dvali et al PRD(02) [as low as 10–3 eV]; Anchordoqui et al PRD(03)hp; Kazakov IJMPD(03)ht; Hong & Hsu PLB(04)hp/03 [brane world]; Han & Willenbrock PLB(05) [radiative corrections and new physics at 1018 GeV]; Meschini FS(07)gq/06 [Planck scale significance]; Calmet & Hsu a0711, Calmet & Feliciangeli a0806 [energy scale in 4D].
@ Against the idea: Mohrhoff MPLA(02)qp [quantum gravity phenomenology = "contradiction in terms", only hep cutoff].

Spacetime Measurements > s.a. causality violations; constants; DSR; modified lorentz symmetry; uncertainty.
* Idea: Quantum uncertainties in the metric limit space and time measurements, modify uncertainty relations; For example, the time of an event cannot be determined with accuracy better than t /t = a0 (tP/t)a, for some a0, a 1.
* Minimal length: Can be expressed in a continuum-based theory through a generalized uncertainty principle, modified dispersion relations, or modified action of the Lorentz group (as in DSR).
@ Limitations: Salecker & Wigner PR(58); in Misner et al 73, 1190ff; Padmanabhan CQG(87); Mashhoon PLA(90); Wheeler PRD(90); Schön gq/93; Amelino-Camelia MPLA(94)gq/96, MPLA(96)gq, PLB(97)gq/96, PLB(00)gq/99; Ng & Van Dam MPLA(94); Jaekel & Reynaud PLA(94)qp/98, QSO(95)qp; Baez & Olson CQG(02)gq, comment Ng & van Dam CQG(03)gq/02; Calmet et al PRL(04)ht, IJMPD(05)ht-GRF; Lloyd qp/05 [covariant, from computation]; Galán & Mena PRD(05)gq [from DSR]; Calmet ht/07-in, MPLA(07)-a0704-in; Amelino-Camelia & Stachel a0710.
@ Minimal length: Heisenberg ZP(43); Aspinwall NPB(94)ht [strings]; Garay IJMPA(95)gq/94; Hinrichsen & Kempf JMP(96)ht/95; Padmanabhan PRL(97)ht/96 [duality]; Amelino-Camelia gq/01-in; Chang ht/04-in; Hossenfelder MPLA(04)hp [and large extra dimensions]; Ahluwalia-Khalilova IJMPD(05)ht [from stabilized Poincaré-Heisenberg algebra]; Hossenfelder CQG(06)ht/05 [consistency of approaches]; Schiller IJTP(06); Maziashvili hp/06; Klinkhamer JETPL(07)gq [different from Planck length]; > s.a. effects on matter.
@ Minimal length and quantum field theory: Brustein et al PRD(02)ht/00; Lieu ApJL(02)ap [hep]; Hossenfelder PRD(06)ht [interpretation].
@ Lorentz invariance: Rovelli & Speziale PRD(03)gq, Livine & Oriti JHEP(04)gq [discrete]; Alfaro et al PRD(04) [lqg, variables].
@ Minimum time: Itzhaki PLB(94)ht; Barbero et al PRD(04)gq/03 [non-perturbative model].
@ Simultaneity: Kok et al qp/02 [distributed entanglement].

And Singularities > s.a. cosmological effects; matter phenomenology [collapse]; models in quantum gravity; singularities; strings; wormholes.
* Singularity avoidance: Early work on Gowdy models using ADM variables was inconclusive; Work on FRW models and black holes by Bojowald et al using connection variables, and by Husain & Winkler using metric variables, indicates that the singularity is avoided there.
@ Avoidance, collapse: Hájícek NPB(01)ht/00, & Kiefer IJMPD(01)gq [spherical shell]; Modesto PRD(04)gq, CQG(06) [black holes]; Husain & Winkler CQG(05)gq/04 [spherical black holes + scalar].
@ Avoidance: Wheeler GRG(77); Padmanabhan CQG(84); Smith & Bergmann PRD(86); Joshi NCB(90); Bramson PRS(93) [particle model]; Russo PLB(94) [need non-trivial topologies]; Callender & Weingard PLA(95) [Bohm theory]; Hosoya CQG(95); Brandenberger gq/95 [cosmological]; Hod gq/99; Hod & Piran GRG(00)gq [censorship]; Gal'tsov gq/01-MG9 [behavior]; Konkowski & Helliwell gq/04-in, et al gq/04-in, gq/04-in [vs classical]; Mallios & Raptis gq/04 [abstract differentil geometry]; Xiang & Shen MPLA(05) [and gup]; Wilson gq/05-in; Esposito et al JPA(06)in [1-loop, euclidean]; Raptis IJTP(06); Bojowald gq/07-ln [rev]; Pitelli & Letelier PRD-a0805 [BTZ black hole]..
@ Avoidance, lqg: Bojowald PRL(05), et al PRL(05)gq [black holes]; Goswami et al PRL(06)gq/05 [scalar collapse, pw(06)jan]; Ashtekar & Bojowald CQG(06)gq/05 [Schwarzschild]; Bojowald CQG(06)gq/05 [degenerate metrics]; Modesto gq/06 [Schwarzschild], ht/07-in [black holes]; Böhmer & Vandersloot PRD(07)-a0709 [Schwarzschild]; > s.a. frw models, quantum black holes.
@ Near singularities: Joshi & Joshi CQG(88); Qadir & Siddiqui CQG(90)-a0801; Krori et al PLA(90); Mazumder IJTP(90) [cosmological]; Smailagic et al ht/03 [0-point length from T-duality]; Damour & Nicolai IJMPD(08)-a0705 [and maximally extended hyperbolic Kac-Moody algebra E10].

Geometry > s.a. discrete models; higher-dimensions; non-commutative geometry; quantum cosmology; quantum gravity; regge calculus.
* Idea: Blurring of st events and metric is expected to lead to fuzziness in causal relations and smearing of singularities.
@ General references: Motoyoshi NCB(93); Sonego PLA(95) [interpretation]; Amelino-Camelia Nat(99)gq/98, PLB(00)gq/99; Amelino-Camelia et al CQG(04)ht/03 [-Poincaré algebra]; Smolin NPB(06)ht/05 [energy-dependent metric, and DSR]; Lehnert gq/07-in [spacetime symmetries].
@ Metric fluctuations: Acebal et al PLB(98), Miller GRG(00) [stochastic model]; Ahluwalia Nat(99)gq; Ellis et al GRG(99)gq-GRF [general]; Frenkel FP(02)qp/00 [Károlyházy]; Hu et al IJTP(04) [semiclassical stability]; Kazakov G&C(04) [and correspondence principle]; Ford IJTP(05)gq-in [test particle Brownian motion]; Requardt MPLA(07)gq/05 [and holographic hypothesis]; Hu & Roura in(07)gq/06 [around a black hole]; Hogan PRD(08)-a0712 [holographic noise and interferometers].
> Related topics: see black hole thermodynamics; differential geometry [generalizations]; differentiable manifolds; manifolds; spacetime foam.

Other Effects and Applications
> The transplanckian issue: see black hole radiation; early universe; inflation; higher-order gravity.
> Specific issues and topics: see Correspondence Principle; entropy bound; observables; Parity [violation]; quantum computing.
> Effects and applications in various areas: see cosmology and gravitation, photons and matter; lorentzian geometry [analogs].


Main pageAbbreviationsJournalsCommentsOther sitesAcknowledgements
Send feedback and suggestions to bombelli at olemiss.edu – Modified 19 jul 2008