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Anisotropic geometrodynamics: observations and cosmological consequences. Sergey Siparov State University of C ivil A viation, St-Petersburg Russia n Federation “Gamov-2009”, Odessa. Motivation (observational ).
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Anisotropic geometrodynamics: observations and cosmological consequences Sergey Siparov State University of Civil Aviation, St-Petersburg Russian Federation “Gamov-2009”, Odessa
Motivation (observational) • Flat rotation curves of spiral galaxies – modern challenge: simple, not small, statistically verified – contradicts the theory!
Attempts to modify the gravitation theory in order to explain flat RC Einstein-Hilbert action • 1. f(R)-theories (De Witt) – where to stop? • 2. Additional scalar fields (Brans-Dicke) – still not found • 3. Weyl tensor (Mannheim) – no GW • 4. Scalar-vector-tensor theory (Moffat) – 5-th force (repulsive) • 5. Phenomenological MOND theory (Milgrem) – arbitrary choice of functions to fit observations • Dark matter notion – inconsistent Unsatisfactory
Astrophysical (observational) restrictions for any gravitation theory modifications • 1. Flat rotation curves • 2. Tully-Fisher law for luminosity: • 3. Globular clusters behavior (I): no need for any correction to the gravitation law outside the spiral galaxy plane (anisotropy ?) • 4. Globular clusters behavior (II): contrary to the Keplerian expectations, they are found rather in the vicinity of the galaxy center than at the periphery • 5. Lensing effect appears to be 4-6 times larger than predicted None is explained by the classical GRT
Suggestion: try anisotropic metricReasons: • Geometry:theaccount for anisotropy is the natural generalization leading to the natural change in the “simplest scalar” in EH action Physics:1)velocity dependent gravitation is consistent with the equivalence principle: it is impossible to distinguish the inertial forces (e.g. Corolis!) from gravitational forces; 2)gravitational force must enter the metric • Introduce where γ_ij - Minkowski metric ε_ij(x,y) - small anisotropic perturbation - directional variable (tangent to trajectory of a probe) u(x) – vector field generating the anisotropy – characterizes the velocities of the distributed gravitation sources
Generalized geodesics and assumptions • Generalized geodesics • Assumptions Use two Einstein’s assumptions: 1. The components y2 , y3, y4 can be neglected in comparison with y1 which is equal to unity within the accuracy of the second order; • 2. The motion is slow, therefore, the time x1-derivative in the equations for geodesics can be neglected in comparison to the space x2-, x3-, and x4-derivatives; Add similar one: • 3. On the y-subspace of the phase space (x,y) the y1-derivative can be neglected in comparison to the y2-, y3-, and y4-derivatives.
Generalized geodesics • Generalized geodesics • Use assumptions k=l=1 yk=yl=1 • Introduce new tensor: to obtain
Geometrical “Maxwell equations” • Anti-symmetric rank-2 tensor suffices: • Use designation: to get • Use designation: to get • Interpretation: charge q - electromagnetism charge m_g - gravitation
Force of gravitation • Equation of motion: • Newton force • Velocity dependent force (analogue: Coriolis (or Lorentz) force) • Third force
Predecessors – GRT corrections for a rotating body in an isotropic space-time • Gravitomagnetism: correction to the spherically symmetric mass gravity due to its rotation. Lense-Thirring: orbit precession. Later: clock effect; Sagnac effect; gravitomagnetic Stern-Gerlach effect; Gravity Probe B – confirmed theory within less than 10% accuracy • Frame-dragging Einstein – geodesics with 3 terms (includes rotational and linear frame-dragging, and inertial mass increase when other masses are nearby) • AGD difference:it is the1-st order theory in an anisotropic space-time
AGD applications – simplified model Attraction center plus circular contourwith current Pay attention to the known one-to-one correlation with Maxwell equations Effective parameters (R_eff, J, V_eff) can be taken from observations
AGD applications - I • Rotation curves (initial goal) Model gives: z = 0; b = r/R_eff = O(1) B_z(r) J/r def: J = C_2 q = m_g = m - Newton law - flat curve -
AGD applications - II • Tully-Fisher law Model: Luminosity:
AGD applications - III • Applicability region and regimes • Illustrative qualitative limit case (giant Black Hole in the center of a galaxy) For M = 10^11M_Sol a_C/a_N = 1 at r ~ 10^18 m v ~ 10^5 m/s Consistent with observations no reason to expect Newton law
AGD applications - IV • Numerical modeling • 1) Quasi-precession, non-Keplerian behavior of globular clusters, and lensing problem • 2) Spiral arms
AGD qualitative results and general cosmological consequences • GRT results remained valid in its applicability region • Flat RC explained • Astrophysical restrictions sufficed • AGD applicability regions determined, limit case checked • Qualitative pictures obtained • Specific prediction: change in the OMPR effect conditions • No dark matter for galaxies needed is it the same for galaxy clusters? • Gravitation ceased to be only attraction can there be no dark energy of repulsion? • Hubble red shift is it Universe expansion or gravitational red shift as it could be according to the observed amazingly fast tangent motion of quasars at the periphery of the visible Universe?
Thank you! S.Siparov, arXiv [gr-qc]: 0809.1817 (2008)