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The Solution of the Fine-Tuning Problem in Extended Quintessence Cosmologies. L. f. Carlo Baccigalupi, Sabino Matarrese, Francesca Perrotta, astro-ph/0403480, submitted to Phys. Rev. Lett. L. Cosmological Constant Problem. Geometry. G mn + g mn = 8 p T mn + V g mn. f. Quantum Vacuum. L.
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The Solution of the Fine-Tuning Problem in Extended Quintessence Cosmologies L f Carlo Baccigalupi, Sabino Matarrese, Francesca Perrotta, astro-ph/0403480, submitted to Phys. Rev. Lett.
L Cosmological Constant Problem Geometry Gmn+gmn=8pTmn+Vgmn f Quantum Vacuum
L Cosmological Constant Problem : ? percent accuracy |-V|/M2Planck=10-123 f 2 V: ? M Planck
?? L for Physics Two ? Why so small with respect to any particle physics scale ? Why comparable to the cosmological critical density today f
w today L f WMAP+ACBAR+CBI+2dF+Ly w < -0.8 (2s ) Spergel et al. 2003
Dark Energy Lagrangian L Extended Quintessence L=f(f ,R)/2-[w(f)/2]f;mf ;m-U(f )- -åk[y;m;m +V(yk)+W(f,yk)] d2f/dt2+3Hdf/dt=(¶f/¶ R)R/2-dU/df If observations require a shallow potential other couplings may play a role in tracking regime G ,f ,y , ...
A flat potential does not mean no dynamics, that may come from other couplings… L f Fig. 1. Quintessence energy density (solid) with quadratic coupling with the Ricci scalar, with respect to matter (dashed )and radiation (dotted dashed)
A non-minimal coupling may restore a large basin of attraction for the Quintessence trajectories L f Fig.2. Same as Fig.1, but with minimal coupling