Fine Structure Constant  

In General > s.a. Landau Pole; renormalization; variation of constants.
* History and value: The constant, introduced by Sommerfeld in 1916, QED:= e2/c = 7.297 352 568(24) × 10–3 = 1/137.03599976... 1/137; 2006 experimental value –1 = 137.035 999 710 (96); 2008 experimental value 137.035 999 084 (51).
@ General articles: PT(71)aug, p18, PT(71)nov, p9, Adawi et al PT(90)dec; Gross PT(89)dec; Nasseri PLB(05), PLB(06)ht/05 [corrections from gup]; Seidel NCB(06) [statistical approach]; Gabrielse et al PRL(06), news pn(06)jun and pw(06)aug [best measurement]; Davies IJTP(08)-a0708 [and gravitational thermodynamics]; Hanneke et al PRL(08) [best measurement].
@ Running, renormalization: Levine et al PRL(97) [evidence]; Tobar hp/03/Met [and flux quanta].
@ Variation, reviews: Fiorentini & Ricci ap/02-in; Murphy et al ap/02-in; Martins ap/04-in.

Variation, Theory > s.a. [cosmological constant]; dark matter; FRW models; general relativistic cosmology.
* History: Dirac (1937) and Landau (1955) proposed that could vary in time.
* Idea: Variations can be driven by changes in the relationship between electric and magnetic field energies.
@ And quintessence: Huey et al PRD(02)ap/01 [and cmb]; Anchordoqui & Goldberg PRD(03)hp; Lee et al IJMPD(05)ap/03 [bound]; Bento et al PRD(04)ap [2-field]; Marra & Rosati JCAP(05)ap; Avelino et al JCAP(06); Lee ap/07/MPLA [and mp/me].
@ And dark matter: Olive & Pospelov PRD(02)hp/01 [+ ]; Barnett et al MNRAS(04)ap [dark matter oscillations].
@ And spectroscopy: Dzuba & al PRL(99)phy/98, PRA(99)phy/98; Bekenstein ap/03.
@ Other: Bekenstein PRD(82) [general framework]; Barrow & Magueijo PLB(98)ap; Bergström et al PRD(99)ap [nucleosynthesis]; Kühne MPLA(99) [-dot implies ]; Banks et al PRL(02) [and quantum field theory]; Damour gq/02-in, Gregori hp/02 [string theory]; Barrow & Mota CQG(03)gq/02 [perturbations]; Rañada EPL(03)ap/02 [as quantum field theory vacuum effect]; Bekenstein PRD(02)gq [and equivalence principle]; Rafelski hp/02 [non-universal gravity]; Fujii ASS(03)gq/02-in [and cosmological constant]; Tobar hp/03 [electromagnetic constants]; Steinhardt PRD(05)hp/03 [constraints]; Belinchón gq/04; Kimberly & Magueijo PLB(04)hp/03 [and standard model]; Kozlov et al PRA(04)ap [and variation of isotope abundances]; Sumner ap/05 [no variation, and no cosmological constant!]; Bandiera & Corbelli A&A(05)ap [mimicked by correlations?]; Campanelli et al MPLA(07)ap/05 [and domain walls]; Karshenboim GRG(06) [search methods]; Fujii PLB(08)-a0709 [scalar-tensor theory, and acceleration]; Anchordoqui et al PLB(08) [phase transition at z = 0.5]..
@ Spatial variation: Barrow et al PRD(02)ap; Mota & Barrow MNRAS(04)ap/03; Parkinson et al PLB(04)ap/03 [mapping the dark energy]; Sigurdson et al PRD(03)ap [and cmb]; Mota ap/04-PhD [BSDM theory].
@ And variation of c: Barrow & Magueijo ap/99/ApJL; Davies et al Nat(02)aug, refuted by Duff ht/02 (refuted by Moffat ht/02), Flambaum ap/02, Carlip & Vaidya Nat(03)ht/02; Magueijo et al PLB(02)ap; Peres IJMPD(03)qp/02, gq/02 [theory]; Alfonso-Faus gq/02/EJP [no].
> Related topics: see black hole thermodynamics; inflationary phenomenology; modified electrodynamics [non-linear]; particles [e mass].

Variation, Consequences > s.a. modified lorentz symmetry.
* Idea: Would imply a non-expansion contribution to redshift, the splitting between atomic energy levels in quasar spectra, and the existence of an ultralight scalar particle; But probably not to a violation of the weak equivalence principle; Would affect stellar nucleosynthesis, a 4% increase in would effectively shut down C production in stars.
@ General references: Berman & Trevisan gq/02; Dvali & Zaldarriaga PRL(02) [5th force and 5essence]; Langacker et al PLB(02) [variations in QCD]; Carlip PRD(03)gq/02 [black holes and quantum gravity]; Tobar & Hartnett PRD(03)gq [proposed experiment]; Bertolami & Monteiro PRD(05) [and primordial B fields]; Flambaum PRA(06) [diatomic molecules].
@ And black hole thermodynamics: Das & Kunstatter CQG(03)ht/02; Fairbairn & Tytgat JHEP(03)ht/02 [RN black hole entropy].

Variation, Observation
* 1997: (gp2)/(gp2) < 5 × 10–6 at z = 0.25, 0.68; / 2 × 10–4 for atoms at z > 1.
* 2000: ·/ 3.5 × 10–15/yr out to t0–t 4.8 Gyr.
* 2001: / 10–5 over 12 × 109 yr (4.1- effect), from metal absorption line spacings in gas clouds, propto 2.
* 2003: / < (–2 1.2) × 10–4 for quasars with 0.16 < z < 0.80, from O III emission lines.
* 2004: / = (–0.06 0.06) × 10–5 for Mg II at 0.4 < z < 2.3, and results for Si IV at 1.59 < z < 2.92, consistent with 0; ·/ 2.0 × 10–15/yr (1-, present).
* 2005: There are still discrepancies, with the deepest data showing an increase by 6 × 10–9 over 12 × 1012 yr, and other data consistent with no change; One possibility is that varied earlier and no longer varies; / = (–0.07 0.84) × 10–6 for Fe II at z = 1.15.
* 2006: Still no agreement on effect; / = (0.05 0.24) × 10–6 at z = 1.1508.
* 2007: Change between recombination (1012 < z < 1115) and now is –0.039 < < 0.010 at 95% c.l., from WMAP3 data.
* 2008: Researchers at NIST have concluded that is not changing to within 1.6 × 10–17 per year.
@ Spectral lines: Webb & al PRL(99)ap/98, PRL(01)ap/00; Varshalovich et al phy/00-in; Murphy et al MNRAS(01)ap/00, ASS(03)ap/02-in [details], MNRAS(03)ap; Darling PRL(03) [OH microwave transitions]; Webb pw(03)apr [rev]; Bahcall et al ApJ(04)ap/03 [O III]; Srianand et al PRL(04)ap, criticism Murphy et al a0708-PRL; Angstmann et al PRA(04)ap [bounds]; Chand et al A&A(04)ap [Mg II], A&A(05)ap/04 [Si IV]; Peik et al PRL(04); Dzuba & Flambaum PRA(05)ap; Grupe et al AJ(05)ap; Levshakov et al ap/05-in [Fe II, z = 1.15, SIDAM]; Chand et al A&A(06)ap; Murphy et al ap/06/MNRAS; Khatri & Wandelt PRL(07)ap + pw(07)mar [effect on 21-cm radiation].
@ Spectral lines, no evidence: Drinkwater et al ap/97-in, ap/97-in, Carilli et al PRL(00)ap + pn(00)dec [21-cm H line]; Levshakov ap/03-in; Quast et al A&A(04)ap/03 [Fe II]; Molaro et al ap/05, a0712-in [Fe II].
@ From cmb: Hannestad PRD(99)ap/98; Kaplinghat et al PRD(99); Avelino et al PRD(01)ap [bounds]; Martins ap/02-in [bounds]; Rocha et al NAR(03)ap-in, MNRAS(04)ap/03 [WMAP, bounds]; Ichikawa et al PRD(06)ap; Stefanescu NA(07)-a0707 [WMAP 3-year data]; Mosquera et al A&A(08)-a0707 [and Bekenstein model].
@ Lab experiments: Livio & Stiavelli ap/98/ApJL; Marion et al PRL(03)phy/02 [atomic fountain clock]; Nguyen et al PRA(04) [dysprosium lines]; Barrow & Shaw a0806 [stronger constraints].
@ Related topics: Fujii & Iwamoto PRL(03) [Re/Os decay rate], MPLA(05) [dating meteorites]; Lamoreaux & Torgerson PRD(04) [Oklo reactor].

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