Connection Representation of Quantum Gravity  

In General > s.a. canonical quantum gravity [including covariant version]; loop quantum cosmology.
* Quantum configuration space: A distributional version of the classical one of connections modulo gauge transformations,

= generalized connections modulo generalized gauge transformations.

* Elementary operators: Heuristically, the Ashtekar new variables (Eai, Aai); In a rigorous approach, the Lie derivatives wrt the left-invariant vector fields on the copy of SU(2) associated with each edge,

or the holonomies along edges and electric fluxes through surfaces.
* Kinematical Hilbert space: The completion of the space Cyl of cylindrical functions, with the measure induced by the Haar measure on SU(2); A nice basis to work with has spin networks as elements; > s.a. projective limit.
@ General references: Ashtekar PRL(86), PRD(87), in(89); Fukuyama & Kamimura PRD(90); Zegwaard CQG(91); Kodama IJMPD(92)gq; Mena IJMPD(94)gq/93 [reality conditions]; Thiemann ACosm(95)gq [transforms], CQG(96)gq/95 [reality conditions]; Rainer gq/99-in [quantum field theory]; Ita a0806 [covariance]; Engle a0812 [piecewise-linear version]; Bianchi et al a0905 [propagator, from new spin-foam models]; > s.a. approaches to quantum gravity; connection formulation of general relativity.
@ Bibliography: Brügmann gq/93; Schilling gq/94; Beetle & Corichi gq/97; Corichi & Hauser gq/05.
@ Representation of basic algebra: Ashtekar et al CQG(98)gq [no triad representation]; Sahlmann & Thiemann CQG(06)gq/03; Fleischhack PRL(06), CMP(09)mp/04; Varadarajan CQG(08) [alternatives].
@ Kinematical : Fairbairn & Rovelli JMP(04)gq [separability]; Okolów CQG(05)gq/04 [non-compact G]; Velhinho CQG(05)gq.
@ Discretized: Renteln & Smolin CQG(89); Loll NPB(95)gq, PRD(96)gq [real variables], gq/97-in, PLB(97)gq [det E > 0], CQG(98)gq/97 [diffeo constraints]; Zapata CQG(04)gq [and lattice gauge theory]; Gambini & Pullin PRL(05)gq/04 [consistent]; > s.a. diffeomorphisms.
@ Other variants: Giesel & Thiemann a0711 [reduced phase space quantization]; Bianchi a0907 [topological field theory with network of defects]; Bahr & Thiemann CQG(09) [towards a combinatorial formulation]; > s.a. loop representation [including deformations].

References > s.a. anomaly; connection; geometrical operators; path-integral quantum gravity; philosophy; Wilson Loops.
@ I: Sen & Butler ThSc(89)nov; Bartusiak disc(93)apr; Vaas bdw(03)phy/04 [and strings]; Rovelli pw(03)nov; Smolin SA(04)jan.
@ Intros, reviews: Ashtekar 88, 91, ht/92, gq/94, in(95)gq/93, IJMPD(96)ht, gq/01-in; Rovelli CQG(91), LRR(98)gq/97; Smolin in(92), gq/92; Ashtekar & Rovelli CQG(92); Ashtekar & Lewandowski ht/93-in; Pullin in(97)gq/96; Gaul & Rovelli LNP(00)gq/99; Thiemann LNP(03)gq/02; Ashtekar & Lewandowski CQG(04)gq [intro]; Smolin ht/04/RMP; Pérez gq/04-ln; Nicolai et al CQG(05)ht [outside view]; Liko & Kauffman CQG(06)ht/05 [and knot theory]; Corichi JPCS(05)gq [geometry]; Han et al IJMPD(07)gq/05; Ashtekar NJP(05); Nicolai & Peeters ht/06-in [intro]; Ashtekar gq/06-in; Thiemann ht/06 [inside view]; Ashtekar NCB(07)gq [introduction through quantum cosmology], a0705-in [faq's]; Han a0706-MS; Thiemann 07, IJMPA(08)-in; Rovelli LRR(08).
@ Immirzi parameter: Immirzi NPPS(97)gq, CQG(97)gq/96; Rovelli & Thiemann PRD(98)gq/97; Gambini et al PRD(99)gq/98 [Yang-Mills version]; Krasnov CQG(99)gq [rotating black holes]; Rainer G&C(00)gq/99 [and black-hole entropy]; Samuel PRD(01); Garay & Mena PRD(02); Mena CQG(02); Dreyer PRL(03)gq/02, Domagala & Lewandowski CQG(04)gq [from black-hole entropy]; Mercuri PRD(08)-a0708 [and large gauge transformations]; Sengupta a0904 [topological interpretation, wave function rescaling]; > s.a. connection formulation of general relativity.
@ Quantum configuration space: Ashtekar & Isham CQG(92); Ashtekar & Lewandowski JMP(95)gq/94, JGP(95)ht/94; Marolf & Mourão CMP(95)ht/94; Doering & de Groote gq/01.
@ States: Jacobson & Smolin NPB(88); Smolin in(88); Husain NPB(89); Brügmann & Pullin NPB(91); Ezawa PRP(97)gq/96; Lewandowski & Marolf IJMPD(98)gq/97 ["vertex-smooth"]; Hari Dass & Mathur CQG(07)gq/06; Ita a0710; > s.a. spin networks.
@ Inner product: Rendall CQG(93)gq; Thiemann CQG(98)gq/97; Bahr & Thiemann CQG(07)gq/06 [approximating].
@ Measure: Baez in(94)ht/93; Baez & Sawin JFA(97)qa/95; Mourão et al JMP(99)ht/97; > s.a. connection.

Constraints and Hamiltonian > s.a. classical version [including reality conditions].
* Gauss law: Can be written vi = I J iv, I , for all vertices v (I labels the edges at v) and internal directions i.
* Solutions of constraints: Heuristically, the quantum Gauss and scalar constraints have been solved for a large set of states which are concentrated on loops in a hypersurface, as well as for some "topological" ones.
@ Hamiltonian constraint: Blencowe NPB(90); Borissov PRD(97)gq/94 [regularization, algebra]; Gambini & Pullin CQG(96)gq [and knot theory]; Thiemann PLB(96)gq, CQG(98)gq/96, CQG(98)gq/96 [operator]; Smolin gq/96 [and long-range correlations]; Borissov et al CQG(97)gq [matrix elements]; Gambini et al IJMPD(98)gq/97 [algebra]; Neville PRD(99)gq/98 [correlations and non-locality]; Di Bartolo et al CQG(00)gq/99 [algebra]; Rovelli PRD(99)gq/98 [projector]; Gaul & Rovelli CQG(01) [all irrep's of SU(2)]; Pérez PRD(06)gq/05 [regularization ambiguities]; Ita a0706, a0707 [general solution].
@ Diffeomorphism constraints: Renteln CQG(90) [lattice regularization]; Loll CQG(98) [on a lattice]; Arnsdorf & García CQG(99)gq/98 [vs vector]; Koslowski gq/06 [stratified]; Ita a0806, a0806 [and Kodama state, dimensional extension].
@ Master Constraint Programme: Thiemann CQG(06)gq/03, CQG(06)gq/05; Han & Ma PLB(06)gq/05; > s.a. dirac quantization.

Special Solutions and Related Topics > s.a. FRW models; gowdy models; inflation; minisuperspace; models; quantum cosmology.
@ Vacuum: Mielke PLA(99) [teleparallel equivalent]; Varadarajan PRD(02)gq [gravitons], CQG(05)gq/04 [graviton vacuum].
@ Symmetries: Thiemann in(94)gq/99, NPB(95) [spherical]; Alexandrov et al CQG(98) [SU(2)-invariant]; Bojowald & Kastrup CQG(00)ht/99 [reduction]; Ma PRD(02)gq/01 [static 2+1 Euclidean + Klein-Gordon].
@ Other topics: Torre CQG(88) [propagator]; Arnsdorf & García CQG(99)gq/98 [spinorial states from topology]; Speziale a0810-ASL [n-point functions]; Yang & Ma a0812 [quasilocal energy]; Botelho a0902 [and fermionic string Ising models]; > s.a. Lemaître-Tolman-Bondi.

With Matter / Cosmological Constant > s.a. matter phenomenology; non-commutative field theory; supergravity; symmetry breaking.
* With cosmological constant: Need to deform SU(2) to SU(2)q , with q = exp{2/k+2}, k:= 6/G2.
@ Scalar: Kiefer PLB(89); Matschull CQG(93)gq; Han & Ma CQG(06)gq; Ita gq/07, a0710.
@ Fermions and Higgs: Baez & Krasnov JMP(98)ht/97; Thiemann CQG(98)gq/97; Montesinos & Rovelli CQG(98)gq; Bojowald et al PRD(08)-a0710 [and early-universe cosmology]; Ita a0805 [scalar and fermion, and Kodama state]; Bojowald & Das PRD(08) [fermions].
@ Other matter: Thiemann CQG(98)gq/97 [standard model]; Lambiase & Singh PLB(03) [matter/antimatter]; Gambini et al GRG(06)gq/04-in [Yang-Mills fields].
@ Cosmological constant: Alexander & Calcagni FP(08)-a0807 [as a Fermi-liquid theory].
@ Chern-Simons-Kodama state: Brügmann et al NPB(92); Crane ht/93-in; Mena CQG(95)gq/94 [non-normalizable]; Gambini et al PLB(97)gq; Soo CQG(02)gq/01; Smolin ht/02 [overview]; Witten gq/03; Freidel & Smolin CQG(04)ht/03 [linearized]; Alexander et al gq/05 [fermionic sectors]; Randono gq/05 [arbitrary Immirzi parameter], gq/06, gq/06, a0709-PhD [real Immirzi parameter]; Ita a0705, a0705, a0706 [canonical and path integral]; Ita a0805, a0901 [Chang-Soo variables], a0806, a0904; > s.a. minisuperspace, quantum gauge theory.

Online Resources > see Wikipedia page; Answers.com page; Dan Christensen's page; Seth Major's reading guide.


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