The Electron |

**In General** > s.a. constants and variation;
Fermions; history of physics; matter.

* __History__: 1892, H A Lorentz, proposal
of the electron and use to explain properties of matter; 1897, J J Thomson,
discovery of the electron as cathode rays; 1924, W Pauli, proposal of an
inner degree of freedom, later associated by Kronig and by Goudsmit and
Uhlenbeck with an inner rotational motion; 1927, C J Davisson & L
H Germer, observation of electron diffraction by a crystal.

* __Charge__: Its absolute
value is *e* = 1.60217733(49) × 10^{–19} C.

* __Mass__: *m*_{e} =
9.109 3826(16)
× 10^{–31} kg ≈ 10^{–27} g
or 511 keV/*c*^{2}, with variation |*μ*^{·}/*μ*_{0}| < 3
× 10^{–14} yr^{–1},
*μ*_{0} = *m*_{p} /
*m*_{e}.

* __Electric dipole moment__:
Since 1950, experimenters have been trying to measure the electron's electric dipole moment *p*_{e} and getting increasingly stringent upper limits, but no clear signal; Initially, the quest seemed dubious because a non-zero *p*_{e} would break symmetries that were then thought to be inviolate; By the mid 1960s it was clear that those symmetries are in fact broken, but the standard model, which incorporates the known symmetry violations, predicts a value *p*_{e} =
10^{–39} *e* · m, far too small to measure; However, beyond-the-standard-model theories predict much higher values, that should be measurable with molecular-beam techniques; 1996, Experimental
bound *p*_{e} ≤ 10^{–27} *e* · m; 2011, Experimental bound *p*_{e} ≤ 1.05 × 10^{–28} *e* · m with 90% c.l.; 2012, Bounds from studies of electrons in solids are not yet as sensitive, but have been improving; 2013, *p*_{e} ≤ 8.7 × 10^{–29} *e* · m with 90% c.l.

* __Magnetic dipole moment__: As of 2006, *g*/2
= 1.001 159 652 180 85 (76); As of 2008, 1.001 159 652 180 73 (28); For an electron bound to an atom *g* deviates from a value close to 2 by terms that depend on the ion's nuclear charge and the fine structure constant.

@ __General references__: Majorana NC(37) [and
positron]; Feynman PR(49)
[positron]; issue PT(97)oct;
Mac Gregor 92; Wilczek SA(12)jun [120th birthday]; Knuth a1511-in [current understanding]; Lincoln TPT(16)apr.

@ __Internal structure__: Robinson PLA(95);
Hofer qp/96,
PhyA(98)qp [and
photons]; Pavšič et al HJ(95)qp/98.

@ __Mass__:
Levshakov et al MNRAS(02)ap/01 [variation
of *m*_{p}/*m*_{e}];
Beier et al PRL(02);
Cardone et al ht/05-ch; Jantzen & Ruffini GRG(12) [Fermi's analysis of the contribution of the electromagnetic field]; > s.a. energy [self-energy].

@ __Magnetic dipole moment__: Welton PR(48)
[and electromagnetic field fluctuations]; Aspden IJTP(77)
[heuristic model]; Vázquez IJTP(79)
[corrections to *g* due to a Coulomb
field]; Jáuregui & de
la Peña PLB(81),
Rivas phy/01 [and
spin]; Awobode NCB(02); Steinmann CMP(03)
[careful definition]; Brodsky et al NPB(04)
[non-perturbative]; McCartor ht/04;
Rosencwaig ht/06 [and
self-energy, Casimir approach]; Awobode NCB(06);
Aoyama et al PRL(07)
[theory, 8th-order contribution]; Hanneke et al PRL(08); Giulini SHPMP(08)
[spin]; Lush a0905 ["hidden
momentum"]; Masood & Haseeb IJMPA(12)-a1204 [corrections at finite temperature]; de Rafael NPPS(12)-a1210 [update, standard model]; Mandache a1307 [physical origin]; Jung JHEP(13) [theoretical bound]; > s.a. Gyromagnetic
Ratio; modified QED.

@ __Electric dipole moment__:
Bernreuther & Suzuki RMP(91); Hudson et al Nat(11)may + news nat(11)may, bbc(11)may,
pw(11)may,
pt(11)jun;
Eckel et al PRL(12) [in solids];
ACME Collaboration Sci(14)jan-a1310 + news SA(13)nov, pw(13)nov [new experimental upper bound].

**Models and Related Topics** > s.a. particle
models [including description as black holes]; particle nature and description; spinning particles.

* __Positron__: 2002, evidence
that in a gas it can form bound states with molecules
[@ Gilbert et al PRL(02)].

* __Decay__: The electron is the lightest known charged particle,
so its decay (for example into a neutrino and a photon) would imply that charge is not always conserved; There are
tight bounds on this process, and the electron lifetime is at least 6.6 × 10^{28} years.

* __Fractionalization__: The phenomenon by which the electron splits into
separate quasiparticles which carry its spin and its charge, and into real
Majorana fermions which carry its Fermi statistics.

* __Speculative__: 2000,
H Maris proposed that electrons can break up into smaller "electrinos" [@
news pn(00)sep].

@ __Extended electron models__: Dirac PRS(62)
[charged conducting surface]; Yaghjian 06 [Lorentz-Abraham charged sphere model]; Likhtman ht/06 [string
model]; Rahaman et al ASS(11)-a0904 [charged
perfect fluid]; Hofer FP(11)-a1002 [geometric-algebra model]; Burinskii AIP(12)-a1104-GRF; Hofer JPCS(12) [and experiment]; Damour CRP-a1710 [Poincaré's 1905 model].

@ __Geometrical models__: Visser PLA(89)
[electromagnetism + Newtonian gravity]; Pavšič et al PLB(93)qp/02 [Dirac
equation from Clifford algebras]; Hofer qp/99-in;
Ray & Bhadra IJMPD(04)gq/02 [Einstein-Cartan
theory]; Giulini HSPMP(08)-a0710 [spin
and special relativity]; Gsponer JMP(08)
[pointlike, in Colombeau's theory]; Atiyah et al JHEP(15)-a1412 [5D Ricci-flat, evolving Taub-NUT geometry];
> s.a. gauge transformations [Maxwell theory].

@ __Other models__: Rosen IJTP(78)
[theoretical approach to mass]; Fryberger PRD(81);
Caldirola LNC(83);
Burinskii JPCS(12)-a1109 [closed heterotic string]; Burinskii a1112-proc;
Kazakov & Nikitin AP(12) [electron freely evolving
in a photon bath, and effective infrared non-divergence].

@ __Positron__: Farmelo CP(10)
[and Dirac]; Leone & Robotti EJP(10), AJP(12)jun
[early history].

@ __Fractionalization__: Xu & Sachdev PRL(10)
+ news physorg(10)aug; news nat(12)apr.

@ __Decay__: Pradhan ht/03;
Klapdor-Kleingrothaus et al PLB(06), Agostini et al PRL(15)
[lower bounds on lifetime].

@ __Angular
momentum__: Stewart CJP(09)qp/07; O'Connell JPA(16)-a1603 [interaction with the angular momentum of the electromagnetic field]; Białynicki-Birula & Białynicka-Birula PRL(17)-a1611 [relativistic wave packets carrying angular momentum]; Bliokh et al PRA(17)-a1706 [position, spin and orbital angular momentum operators].

@ __Related topics__: Matteucci AJP(90)dec
[wave behavior]; Rivas JPA(03)phy/01 [dynamical
equations]; Matteucci et al EJP(09)
[wave behavior]; Cetto et al QS:MF(17)-a1707 [origin of electron spin and related wave function antisymmetry]; > s.a. locality; lorentz-symmetry
violation; Stochastic Electrodynamics.

**Applications and Experiments** > s.a. bose-einstein condensates; condensed-matter physics; Density Functional Method; Luttinger
Liquid.

@ __Gas of free electrons__: Verzegnassi et al a1706 [effect of a magnetic field, qft treatment].

@ __Electrons in materials / lattices__: Alloul 11 [in solids]; news pw(12)oct [nanocloaking devices for electrons inside materials]; Bach & Delle Site ch(14)-a1406 [open problems in many-electron theory]; Klopp & Veniaminov a1408 [interacting, in a random background]; news brown(14)oct [electron bubbles in ultracold liquid helium]; news upi(16)feb [electrons in graphene behaving as fluid]; Martin et al 16; Quinn a1706 [strongly correlated regime]; > s.a. Hofstadter's Butterfly.

@ __Experiments and techniques__: Richter Phy(12)feb [controlling electron spin and geometric phase]; Sancho a1601 [charge distribution, via Kapitza-Dirac diffraction].

@ __Magnetic moment, measurements__: Odom et al PRL(06)
+ pn(06)jul [best measurement];
Gabrielse pw(07)feb [implications];
Vogel CP(09) [and test of QED];
Sturm et al PRL(11) [in a bound state, stringent test to date of QED].

@ __Magnetic moment, effects__: Mera et al PRB(13)-a1206 [in a ferromagnet, interaction with conduction band electrons and with phonons].

> __ Related topics__: see aharonov-bohm effect; diffraction; scattering; Wigner Crystal.

You know, it would be sufficient to really understand the electron – Albert Einstein

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2018