Charges  

In General > s.a. G-parity; Isospin; noether charge; topology in physics.
* Idea: Loosely speaking, a charge is a conserved quantity other than energy-momentum.
* And conserved currents: When a charge is conserved because it is associated with a conserved current, it can be calculated as a surface integral (see examples below); > s.a. conservation laws.

In a Gauge Theory > s.a. electromagnetism; gauge theory.
* Abelian electric charge: The electric charge of an isolated system is

Q =  S Fab dsab = S F 0b dsb = S Ea dsa ,

where S is any closed (N–1)-surface in N+1 spacetime dimensions enclosing the system, possibly a surface at infinity, Sinfty.
* Non-abelian theory: The electric and magnetic charges Q and F have internal indices; For a Yang-Mills theory they are, respectively,

Q ij = (4)–1 S Eaij dsa   and   P =  S *Fab dsab = S Ba dsa ;

Several electric and magnetic charges can actually be defined; 'Brane source charge' is gauge invariant and localized but not conserved or quantized, 'Maxwell charge' is gauge invariant and conserved but not localized or quantized, while 'Page charge' conserved, localized, and quantized but not gauge invariant [@ Marolf ht/00-in].
@ Abelian, electric charge: Segers et al AJP(09)jan [Einstein's "little machine" to measure small charges].
@ General references: Sniatycky & Schwartz RPMP(94) [no local non-abelian charge density]; Marolf ht/00-in; Lyre IJMPD(00)gq [equivalence principle for charge]; Barnich CQG(03)ht [boundary charges]; McMullan Sigma(07)ht; > s.a. topology in physics.

Other Systems > s.a. particle types.
@ In gravity: Hollands et al PRD(05)ht/05 [counter-term subtraction definition]; > s.a. Anti-de Sitter; gravitational energy.

References > s.a. renormalization.
@ General: Klauder & Wheeler RMP(57) [re neutrinos]; Toussaint GRG(00)gq/99 [general relativity / gauge theory]; Hofer qp/00 [origin?].
@ Quantization: Staruszkiewicz AP(89); Rañada & Trueba PLB(98)ht [topological]; Rañada ht/99; Olive ht/01-in; Allen et al ht/02; Pérez-Lorenzana & Pires MPLA(03) [higher dimensions]; Barone & Helayel-Neto qp/04-in, comment MacKenzie et al qp/05 [and Aharonov-Bohm effect]; Minguzzi et al JPA(06) [from weak gauge principle]; > s.a. experiments, kaluza-klein.
@ Fractional charges: Wilczek cm/02-in; Gies et al PRL(06) [unquantized 'millicharged fermions', search]; > s.a. Hall Effect [fractional]; Quarks.


main pageabbreviationsjournalscommentsother sitesacknowledgements
send feedback and suggestions to bombelli at olemiss.edu – modified 15 jun 2009