Minisuperspace Quantum Cosmology  

In General > s.a. models in canonical quantum gravity [including midisuperspace]; geometrodynamics [superspace].
* Idea: Restrict the number of degrees of freedom of the metric to a finite number, by imposing symmetries; Consequences are that (1) The quantum constraints become easier to handle, when written in the usual variables; (2) Since we allow fewer metric variations when getting the equations of motion from the action, we may get more classical solutions, some spurious ones being unstable; (3) Semiclassically and in quantum theory, the results may not be equivalent to appropriate sectors of the full theory.
@ General references: Kiefer PRD(88); Morikawa PRD(89); Nagai PTP(89); Guven & Vergara PRD(91); Shabanov PLB(91); Torre IJTP(99); Bojowald et al CQG(04)gq/03 [and spin connection]; Cognola & Zerbini gq/04 [rev]; Capozziello et al CQG(08)-a0706 [tomographic representation]; Halliwell JPCS(11)-a1108 [decoherent-histories analysis]; Barvinsky & Kamenshchik PRD(14)-a1312 [selection rules for the Wheeler-DeWitt equation]; Bojowald & Brahma PRD(16)-a1509 [as infrared contributions]; Pal & Banerjee JMP(16)-a1601, Pandey a2101-PhD [and unitarity].
@ Limits of validity: Kuchař & Ryan PRD(89); Sinha & Hu PRD(91) [from quantum field theory in curved spacetime]; Mazzitelli PRD(92) [corrections from midisuperspace]; Rovelli & Wilson-Ewing PRD(14)-a1310 [and the accuracy of the effective equations of lqc]; > s.a. semiclassical cosmology.
@ Canonical and path integral: Marolf in(95)gq/94 [spectral analysis inner product]; Marolf PRD(96)gq; Menotti & Peirano NPB(97)ht/96 [measure]; Simeone PLA(03); Qin & Ma PRD(12)-a1110 [coherent state functional integrals, and Moyal star product]; Christodoulakis et al JGP(13)-a1208 [and constrained symmetries].
@ Noether symmetries: Capozziello & Lambiase GRG(00)gq/99, GRG(00)gq/99; Capozziello et al EPJC(12)-a1206; Capozziello & De Laurentis a1308-proc [in extended gravity theories].
@ Related topics: Calzetta CQG(89) [dissipation and memory loss]; Hu et al gq/93-proc [dissipative processes]; Embacher gq/96, NPPS(97)gq/96 [decompositions]; Krori CQG(96) [and conformal degree of freedom]; Simeone JMP(98)gq/01 [as gauge theory]; Cavaglià IJMPD(99)gq/98 [approximate quantization]; Montani IJMPD(04)gq [revised canonical quantum gravity]; Marolf PRD(09)-a0902 [observables and problem of time].

Bianchi Models > s.a. loop quantum gravity [homogeneous and isotropic cosmologies]; semiclassical cosmology; spin-foam models.
@ Type II: Manojlović & Mena PRD(93)gq; Christodoulakis et al PLB(97); Christodoulakis & Papadopoulos PLB(01)gq/00; Christodoulakis & Papadopoulos gq/01 [and VIA, VIIA]; Ashtekar & Wilson-Ewing PRD(09)-a0910 [lqc, singularity resolution]; Corichi & Montoya PRD(12)-a1201 [lqc, with a massless scalar field]; Bergeron et al PRD(14)-a1405; Farag Ali & Majumder CQG(14)-a1402 [with gup]; Saini & Singh CQG(17)-a1707 [lqc, singularity resolution]; Pandey a2101-PhD.
@ Types III-VII: Hojman et al PRD(92) [Hamiltonian from equations of motion]; Christodoulakis et al PRD(96) [V], PLB(98) [V], PLB(01)gq [VI and VII vacuum]; Pandey a2101-PhD [VI]; > s.a. quantum cosmology [other theories].
@ Type VIII: Karagiorgos et al JCAP(19)-a1812 [and IX]; Berkowitz a2102 [with Λ, electromagnetic and scalar fields; and IX].
@ Type IX: Misner PR(69); Kodama PRD(90); Giampieri PLB(91); Jensen et al NPB(91); Louko PRD(95)gq/94 [Chern-Simons state and Hartle-Hawking boundary conditions]; Major & Smolin PRD(95)gq/94, gq/96; Marolf CQG(95)gq/94 [observables and Hilbert space]; Graham & Paternoga PRD(96)gq [from Chern-Simons state]; Paternoga & Graham PRD(96)gq [Λ < 0]; Savchenko et al IJMPA(99)gq, IJMPA(00)gq; Macías GRG(99); Craig & Hartle PRD(04)gq/03 [generalized sum over histories]; Kheyfets et al CQG(06)gq/05 [non-Dirac, expectation value of constraints]; Marcianò a1003-MG12 [inhomogeneities]; Bergeron et al PRD(15)-a1501 [singularity avoidance], PRD(16)-a1511 [inflationary aspects]; D'Odorico & Saueressig PRD(15)-a1511 [asymptotic safety motivated corrections, phase transition]; Giovannetti & Montani PRD(19)-a1907 [polymer quantization]; Bergeron et al Univ(20)-a1911 [quantum Mixmaster and the early universe]; Chiovoloni et al a2005 [corner region]; > s.a. quantum cosmology [inhomogeneities].
@ Type IX, affine coherent states: Bergeron et al PRD(15)-a1501; Małkiewicz a1512-MG14.
@ Type IX, supersymmetric: Graham PLB(92); Graham & Bene PLB(93) [+ scalar]; Moniz gq/95-conf, IJMPA(96)gq/95; Damour & Spindel PRD(14)-a1406.
@ Type IX, lqc: Bojowald & Date PRL(04)gq/03; Battisti et al PRD(10)-a0911 [triangulated]; Wilson-Ewing PRD(10)-a1005; Corichi & Montoya CQG(16)-a1502 [effective dynamics]; Corichi & Karami IJMPD(16)-a1605 [inverse triad corrections]; Saini & Singh CQG(18)-a1712 [singularity resolution]; Crinò et al EPJC(18)-a1805 [and semiclassical behavior]; Wilson-Ewing CQG(19)-a1809 [extension].
@ Chaos: Berger PRD(89) [vacuum IX, chaotic]; Graham CSF(95)gq/94 [VIII and IX]; Bojowald et al CQG(04)gq [vacuum IX, lqg, non-chaotic behavior]; in Matinyan ht/06-MGXI; Forte CQG(09)-a0812 [and billiard representation]; Koehn PRD(12)-a1107 [wave packets and quantum cosmological billiards]; Lecian et al PRD(13)-a1311 [polymer representation]; > s.a. semiclassical cosmology.
@ In lqc / lqg: Bojowald CQG(00)gq/99 [class A], CQG(03)gq; Bojowald et al CQG(06)gq/05 [anisotropies]; Ita a0812 [gravity + Klein-Gordon], CQG-a0901 [Chang-Soo/CDJ variables]; Lamon a0909 [3-torus space]; Eder a2010 [supersymmetric]; > s.a. FLRW cosmology.
@ Supersymmetric, supergravity: Capovilla & Guven CQG(94)gq [class A, Ashtekar variables]; Capovilla & Obregón PRD(94)gq [class A, with a cosmological constant]; Socorro & Medina PRD(00)gq/99 [class A].
@ General class A: Ashtekar et al gq/93; Christodoulakis et al G&C(02)gq/94 [framework]; Yamazaki gq/01 [Dirac sqrt]; Wilson-Ewing PRD(16)-a1512 [diagonal, with self-dual variables].
@ Other models: Christodoulakis & Korfiatis JMP(92) [with a scalar field]; Ashtekar et al IJMPD(93)gq [observables and quantization]; Damour & Spindel PRD(11)-a1103 [with a Dirac spinor field]; > s.a. bianchi models; bianchi I quantum cosmology [including affine quantization].

Wormholes, Baby Universes > s.a. cosmology [philosophical]; wormholes; quantum gravity and cosmology [Hartle-Hawking proposal].
@ Effective action, decoherence: Hájíček PRD(82), PRD(82); Hawking PLB(87), PRD(88); Coleman & Lee PLB(89).
@ Applications: Lee PRL(88) [scalar field and effective interaction]; Accetta et al PRD(89).
@ Baby universes: Hawking & Laflamme PLB(88) [and non-renormalizability]; Giddings & Strominger NPB(89); Myers NPB(89); Borde et al PRD(99) [in monopole collisions]; Vachaspati a0705-GRF.
@ Related topics: Lyons NPB(89) [fermions]; Volovich PLB(89) [spacetime dimension].

Other Models and Theories > s.a. Discrete Models; non-commutative cosmology; path integrals; quantum cosmology models; string cosmology.
* Microsuperspace: A model in which the sum over histories reduces to a finite number of ordinary integrals.
@ References: Halliwell & Louko PRD(89) [S4 microsuperspace]; Sawayama gq/06 [static inhomogeneous]; Kamenshchik et al PRD(19)-a1905 [induced gravity]; Baytaş et al JCAP(20)-a1905 [causal dynamical triangulations]; > s.a. anti-de sitter space; FLRW models; kantowski-sachs models; models in canonical quantum gravity; Taub Universe.

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