|  Spherically Symmetric Geometries | 
In General > s.a. trigonometry.
  $ Idea: A spacetime is spherically symmetric
    if it admits SO(3) as an isometry group, with 2D surfaces of transitivity.
Spacetime Metric
  * Most general form:
    It can be parametrized in different ways, e.g.,
ds2 = −f(r, t) dt2 + h(r, t) dr2 + k(r, t) dΩ2 or − eν(r, t) dt2 + eλ(r, t) dr2 + r2 dΩ2 .
  * Most general static form: Without loss
    of generality, can be written as ds2
    = −f(r) dt2
    + h(r) dr2
    + r2 dΩ2.
  * Painlevé-Gullstrand form: A form in which
    the spatial metric is flat, with line element ds2
    = −[c2(r, t)
    − f 2(r, t)]
    dt2 − 2 f(r, t)
    dr dt + dr2
    + r2 dΩ2.
  @ References: Husain et al PRD(02)gq/01 [flat foliations];
    Gundlach & Martín-García PRD(03)gq [discretely self-similar];
    Ferrando & Sáez CQG(10)-a1005,
    CQG(17)-a1701 [intrinsic characterization, ideal labeling];
    Parry AMP(14)-a1409 [survey];
    Akbar PLB(17)-a1702 [spacelike geometries].
  @ Painlevé-Gullstrand form: Martel & Poisson AJP(01)qg/00;
    in Visser IJMPD(03)ht/01;
    Fischer & Visser AP(03)cm/02 [effective geometry];
    Natário GRG(09)-a0805 [for Kerr spacetime];
    Lin & Soo PLB(09)-a0810 [generalized];
    Finch a1401 [for the 5D Myers-Perry black hole];
    MacLaurin a1911 [for Schwarzschild spacetime];
    > s.a. Painlevé-Gullstrand Coordinates [other spacetimes];
      schwarzschild spacetime;
    Wikipedia page.
  > Special types:
    see bianchi metrics; kantowski-sachs solutions;
    FLRW spacetime; schwarzschild spacetime.
  > Related topics:
    see Extremal Surface; Hypersurface;
    killing fields; metric matching;
    Pseudosphere; rotations;
    Trapped Surface.
Connection and Curvature > s.a. sphere.
  * Connection coefficients:
    The non-equivalent, non-vanishing ones are
| Γ000
    = \(1\over2\)ν·
    = \(1\over2\)f ·/f Γ010 = \(1\over2\)ν' = \(1\over2\)f '/f Γ011 = \(1\over2\)λ· exp{λ−ν} = \(1\over2\)h·/f Γ100 = \(1\over2\)ν' exp{ν−λ} = \(1\over2\)f '/h | Γ101
    = \(1\over2\)λ·
    = \(1\over2\)h·/h Γ111 = \(1\over2\)λ' = \(1\over2\)h'/h Γ122 = −exp{−λ}r = −r/h Γ133 = −exp{−λ}r sin2θ | Γ212
    = r−1 Γ233 = −sinθ cosθ Γ313 = r−1 Γ323 = (tanθ)−1 . | 
* Riemann tensor: The non-equivalent, non-vanishing components are
| R0101 = \(1\over2\)λ·· exp{λ−ν} −\(1\over2\)ν'' + \(1\over4\)(λ· )2 exp{λ−ν} −\(1\over4\)ν'2 −\(1\over4\)λ·ν· exp{λ−ν} + \(1\over4\)λ'ν' | |
| R0202
    = −\(1\over2\)ν' exp{−λ}r R0303 = −\(1\over2\)ν' exp{−λ}r2 sin2θ R0212 = −\(1\over2\)λ· exp{−ν}r R0313 = −\(1\over2\)λ· exp{−ν}r sin2θ | R1212
    = \(1\over2\)λ' exp{λ}r R1313 = \(1\over2\)λ' exp{λ}r sin2θ R2323 = (1−exp{−λ}) sin2θ . | 
Generalizations
  > s.a. spherical symmetry in general relativity [locally spherically symmetric spacetime].
  $ Pseudospherically symmetric
    spacetime: A spacetime, invariant under the action of the 3D Lorentz
    group, whose surfaces of transitivity are timelike and 2D, with line element
    ds2 = −s2
    [(1−x2)−1
    dx2 − (1−x2)
    dt2].
Spherical Symmetry in Classical Field Theory
  > s.a. distributions.
  @ Spherically symmetric perturbations:
    Seifert & Wald PRD(07)gq/06 [diffeomorphism-covariant theories, variational principle].
  > In gravity theories: see
    bimetric gravity; conformal gravity;
    einstein-cartan theory; hořava gravity;
    massive gravity;  scalar-tensor theories;
    spherical solutions in gravity theories [including higher-order theories and
    theories with torsion].
  > In other theories: see
    klein-gordon theory; solutions in gauge theory.
Spherical Symmetry in Quantum Field Theory > see loop quantum gravity; singularities in quantum gravity.
 main page
  – abbreviations
  – journals – comments
  – other sites – acknowledgements
  send feedback and suggestions to bombelli at olemiss.edu – modified 26 apr 2021