String Theory Phenomenology

Particle Physics in General > s.a. axions; CPT symmetry; GUTs; higher-spin fields; neutrino; yang-mills theory.
* Idea: The lowest excited modes of open strings correspond to massless spin-1 particles (the photon, \(W^\pm\), \(Z\) and gluons); Those of closed strings are massless spin-2 particles (the graviton).
* Enhançon: A hypersurface (spherical in the initial proposal), apparently made of D-branes, which arises in string theory studies of large-N SU(N) pure gauge theories with eight supercharges.
@ General references: Faraggi ht/97-proc, ht/99-proc; Quevedo NPPS(98)hp/97; Ibáñez CQG(00)hp/99-proc; Sudarsky et al PRD(03) [bounds from low-energy data]; Dine PT(07)dec [rev]; Antoniadis IJMPA(10) [rev]; Ibáñez a1204-ln [rev]; Ibáñez & Uranga 12; Faraggi a1404-conf; Kane IJMPA(15) [how to make contact with the 4D world]; Kane a1601 [string theory is testable]; Quevedo a1612-conf.
@ And QCD: Aharony ht/02-ln; Evans pw(03)may; Mateos CQG(07)-a0709-ln; Lüst IJMPA(10).
@ And gauge theory: Polyakov NPPS(98)ht/97 [confinement], IJMPA(99); Ghilencea & Groot Nibbelink CQG(03) [corrections to couplings]; Imeroni PhD(03)ht; Sugimoto & Takahashi JHEP(04)ht [and QED]; Caselle et al JHEP(05)hl [Nambu-Goto string and interquark potential]; Heckman CP(10) [F-theory GUTs and experiment].
@ Accelerator physics: Dudas & Mourad NPB(00)ht/99; Antoniadis & Benakli IJMPA(00), Antoniadis IJMPA(06)in [also branes]; Distler et al PRL(07)hp/06 + sr(07)jan [prediction and falsifiability in W-boson scattering]; Anchordoqui et al NPB(09); Anchordoqui et al PRD(14)-a1407 [hadron colliders].
@ Enhançon: Jarv & Johnson PRD(00)ht; Johnson PRD(01)ht/00; Astefanesei & Myers JHEP(02)ht/01, Dyson et al JHEP(02)ht/01 [non-spherical]; Merlatti NPB(02)ht/01 [fractional branes].

And Gravity > s.a. brane world; covariant quantum gravity and other approaches; quantum-gravity phenomenology.
* Idea: While the matter content of the theory is dependent on the compactification, in string theory the presence of gravity in the spectrum is universal; General relativity is recovered in the sense of an effective interaction between strings in scattering processes; Early suggestions were from Scherk & Schwarz &(74) and Yoneya &(74); The first correction to the action for general relativity is a Gauss-Bonnet term; String theory yields ultraviolet finite scattering amplitudes in theories of gravity coupled to matter.
* Questions: Get black holes (and black-hole evaporation); Planck-scale behavior (Are there singular solutions? Are they generic? Singularity theorems?).
* Problem: Conformal ambiguity in the physical metric.
* Black-hole information paradox: It is resolved by the picture of quantum black-hole microstates as horizon-sized objects called 'fuzzballs' instead of vacuum regions with a central singularity; Causality requires that the wavefunctional has an important component not present in the semiclassical picture, virtual fuzzballs; The large mass of the fuzzballs suppresses their virtual fluctuations, but this suppression is compensated by the large number exp\([S_{\rm B}(M)]\) of possible fuzzballs, which are extended compression-resistant objects; The presence of these objects in the vacuum wavefunctional alters the physics of collapse when a horizon is about to form, avoiding the information paradox; > s.a. Fuzzballs.
@ Books, reviews: Giddings hp/05-ln; Yoneya a0901-ch [hist, 1969-1974]; Blau & Theisen GRG(09) [open questions]; Elvang & Horowitz a1311-ch; Ortín 15.
@ General references: Boulware & Deser PRL(85); Sannan PRD(86); Banks & Lykken NPB(90); Smolin gq/96; Branson et al PLB(97)ht/96; Porrati LMP(99) [and general relativity]; Green CQG(99)A; Aharony et al PRP(00) [and large-N field theories]; Wessling & Wise PLB(01)ht; Polyakov IJMPA(02)ht/01 [thoughts]; Siegel ht/03 [weakening at short scales]; Horowitz NJP(05)gq/04 [spacetime]; Arkani-Hamed et al JHEP(07)ht/06 [string landscape and quantum gravity]; Roberts ht/06 [unified field theory]; Damour & Lilley a0802-ln; Wadia a0809-in [rev, semi-technical]; Deo et al G&C(09) [quantum gravity]; Basu CQG(16) + CQG+ [one-loop gravitational interactions].
@ Gravitational waves: Brustein ht/96 [background]; Allen & Brustein PRD(97)gq/96 [and LIGO]; Ungarelli & Vecchio AIP(00)gq/99; Cartier et al NPB(01) [string cosmology].
@ Black holes: Gimon & Hořava PLB(09)-a0706 [superspinning, violating the Kerr bound]; Mathur a1812-proc [virtual fuzzballs]; Pietri a1911-PhD; > s.a. quantum black holes.
@ Solutions: Coley PRL(02) [vanishing curvature invariants]; Petri gq/04 [holographic]; Hernández et al G&C(09) [stationary axisymmetric]; > s.a. black holes.
@ Supergravity: Witten NPB(95)ht; Aspinwall NPPS(96)ht/95; Stelle ht/05-proc [divergence structure]; Deo IJMPA(06)ht/05 [derivation]; Gaillard a1602-in; Reid-Edwards & Riccombeni JHEP(17)-a1701 [superstring field theory].
> Related topics: see corrections to newtonian gravity; graviton; quantum spacetime; spacetime; schwarzschild spacetime; uncertainty.

Astrophysics and Other Areas > s.a. anthropic principle; string cosmology.
* Landscape: The name refers to a plot shaped like a mountainous landscape, where altitude represents the cosmological constant, with its value settling on a low point somewhere between the peaks of the landscape; But there could be on the order of 10⁵⁰⁰ possible such low points, and no obvious reason for the universe to pick the one we observe; Seen either as a virtue (e.g., in parallel worlds scenarios) or as a sign of inability to make predictions.
@ General references: Kane PT(97)feb; Musser SA(02)oct; Gates PT(06)jun; editorial pw(07)sep; Kane PT(10)nov.
@ Astronomy / astrophysics: Mavromatos JPCS(09)-a0903 [high-energy gamma rays]; Ellis et al PRD(19)-a1810 [D-particles and the hydrogen 21-cm line].
@ Applications to other areas: Borsten et al PRL(10) + wired(10)sep [and four-qubit entanglement classification]; McGreevy Phy(10) + nat(10)oct [strange metals]; > s.a. condensed matter physics.
@ Landscape: Quevedo pw(03)nov; Bousso & Polchinski SA(04)sep; Douglas ht/06-conf; Schellekens phy/06 [general audience]; Conlon CP(06); Acharya & Douglas ht/06 [finite?]; Rej a0909-FQXi [decidability, computability and complexity]; Smolin FP(13)-a1202 [historical roots and speculative scenarios]; Banks a1208.

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