|  Fine-Structure Constant | 
In General > s.a. variation of constants;
  bounds on fine-structure constant variation.
  * History and value: The
    constant, introduced by Sommerfeld in 1916 in his study of the hydrogen
    atom, αQED:=
    e2/\(\hbar\)c
    = 7.297 352 568(24) × 10−3
    = 1/137.03599976... ≈ 1/137; 2006 experimental value
    α−1
    = 137.035 999 710 (96); 2008 experimental value 137.035 999 084 (51).
  * Running, renormalization:
    At about 100 GeV (LEP energies), the value is 1/128.9; It should keep growing
    at higher energies, and diverge at a very high but finite energy
    (> Landau-Pole Problem; renormalization).
  @ General articles: Lubkin PT(71)aug,
    letter PT(71)nov,
    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];
    Davies IJTP(08)-a0708 [and gravitational thermodynamics];
    Gogberashvili & Kanatchikov a1009 [in a Machian universe];
    Mainland & Mulligan a1705 [theoretical calculation].
  @ Measurement: Gabrielse et al PRL(06),
    news pn(06)jun
    and pw(06)aug [best];
    Hanneke et al PRL(08) [best];
    Maciejko et al PRL(10) [using a topological insulator];
    Bouchendira et al AdP(13)-a1309 [state of the art].
  @ Running, renormalization:
    Levine et al PRL(97) [evidence];
    Tobar Met-hp/03 [and flux quanta];
    Toms PRL(08)-a0809 [quantum gravity corrections];
    Eichhorn et al PLB(18)-a1711 [quantum-gravity predictions, asymptotic safety].
  @ Anthropic arguments: Eaves PhyA(16)-a1412 [anthropic fine-tuning];
    Sandora JCAP(16)-a1604 [anthropic requirements for habitable planets].
  @ Related topics: Jentschura PRA(14)-a1404
      [gravitational fine-structure constant αG
      = Gm1m2/\(\hbar\)c].
  @ Variation, reviews: Fiorentini & Ricci ESO(03)ap/02;
    Murphy et al eConf-ap/02;
    Martins ap/04-proc;
    Scóccola PhD(09)-a0906 [and electron mass].
Variation, Theory > s.a. cosmological
  constant / cosmology in modified gravity;
  dark matter; FLRW
  models; higher-order gravity.
  * History: Dirac (1937) and Landau (1955)
    proposed that α could vary in time.
  * Idea: Variations can be driven
    by changes in the relationship between electric and magnetic field energies.
  @ General references:
    Bekenstein PRD(82) [framework];
    Karshenboim GRG(06) [search methods];
    Barrow AdP(10)-a0912-proc [rev].
  @ 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 MPLA(07)ap
      [and mp/me];
    Bento & González PLB(09).
  @ And dark matter: Olive & Pospelov PRD(02)hp/01 [+ Λ];
    Barnett et al MNRAS(04)ap [dark matter oscillations];
    Stadnik & Flambaum PRL(15)-a1503.
  @ And spectroscopy: Dzuba & al PRL(99)phy/98,
    PRA(99)phy/98;
    Bekenstein  ap/03.
  @ And the cosmological constant: Kühne MPLA(99) [α-dot implies Λ];
    Fujii ASS(03)gq/02-conf.
  @ Other: Barrow & Magueijo PLB(98)ap;
    Bergström et al PRD(99)ap [nucleosynthesis];
    Banks et al PRL(02) [and quantum field theory];
    Damour ASS(03)gq/02-conf,
    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];
    Tobar Met-hp/03 [electromagnetic constants];
    Steinhardt PRD(05)hp/03 [constraints];
    Belinchón gq/04;
    Kimberly & Magueijo PLB(04)hp/03 [and the standard model];
    Kozlov et al PRA(04)ap [and variation of isotope abundances];
    Campanelli et al MPLA(07)ap/05 [and domain walls];
    Fujii PLB(08)-a0709 [scalar-tensor theory, and acceleration];
    Anchordoqui et al PLB(08) [phase transition at z = 0.5];
    Bekenstein & Schiffer PRD(09)-a0906 [and black holes];
    MacGibbon a1003-MG12 [and generalized second law];
    Barrow & Lip PRD(12)-a1110 [generalized theory];
    Sloan CQG(14)-a1307 [in lqc].
  @ 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 PhD(03)ap/04 [BSDM theory];
    Olive et al PRD(11)-a1011 [and domain walls];
    Barrow & Magueijo MPLA(15)-a1412.
  @ And variation of c:
    Barrow & Magueijo ApJL(00)ap/99;
    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].
  @ No variation, alternative interpretations: Sumner ap/05 [and no cosmological constant!];
    Bandiera & Corbelli A&A(05)ap [mimicked by correlations?];
    Chang et al EPJC(12)-a1106 [spacetime anisotropy].
  > Related topics: see black-hole thermodynamics;
    inflationary phenomenology; modified electrodynamics
    [non-linear]; particles [electron mass].
Variation, Consequences
  > s.a. modified lorentz symmetry.
  * Idea: It 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; It would
    affect stellar nucleosynthesis, a 4% increase in α 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 ΛQCD];
    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),
    Flambaum & Kozlov PRL(07),
    Beloy et al PRA(10) [diatomic molecules].
  @ And black-hole thermodynamics: Das & Kunstatter CQG(03)ht/02;
    Fairbairn & Tytgat JHEP(03)ht/02 [Reissner-Nordström black-hole entropy].
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