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T he Cosmological Constant, Inflation, and Dark Energy * John D. Barrow

T he Cosmological Constant, Inflation, and Dark Energy * John D. Barrow. T = 2.7255  0.0006 K. Y(He-4)= 4  He/H = 0.2534  0.0083 D/H = 2.87  0.22  10 -5. New Physics?. N eff = 3.046 is standard 3 light neutrino standard model.

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T he Cosmological Constant, Inflation, and Dark Energy * John D. Barrow

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  1. The Cosmological Constant, Inflation, and Dark Energy * John D. Barrow

  2. T = 2.7255  0.0006 K

  3. Y(He-4)= 4He/H = 0.2534  0.0083 D/H = 2.87  0.22  10-5

  4. New Physics? Neff = 3.046 is standard 3 light neutrino standard model

  5. Habitable UniversesNeedClose to critical expansionIsotropic expansionGraininess level of about 1 part in 105

  6. Inflation Early-time inflation at t  10-35 s

  7. Acceleration requires  + 3p/c2 <0

  8. 1992 2003 2013

  9. Planck Mission Microwave Sky Map

  10. The Spectrum of Temperature Fluctuations

  11. Scalar Fields and Lambda Pressure: p = ½(d/dt)2 – V() = KE - PE Energy density:  = ½(d/dt)2 + V() = KE + PE V -c2 ≤ p ≤ +c2  • d2a/dt2 = - 4G( + 3p/c2)a/3 > 0 • + 3p/c2 < 0 Necessary for inflation But kills the singularity theorems d/dt=0 p =-

  12. Eg with non-constant V Pressure: p = ½(d/dt)2 – V() = KE - PE Energy density:  = ½(d/dt)2 + V() = KE + PE

  13. ns = -3(V’/V)2 + 2(V’’/V)  O(1/N)  O(1/50) dns /dln(k) = 2[4(V’/V)2 (V’’/V) – 3(V’/V)4 –V’V’’’/V2]  O(1/N2,1/N3) Gravitational Potential perts  1/(size)ns  kns

  14. Our Universe can have a beginningBut The Multiverse need have no beginning

  15. Was there a beginning? no yes Eternal cycles Eternal change Beginning of time Beginning in time no end In the future will end In the future Creation out of nothing Creation out of something order chaos order is transient order is permanent

  16. Infinities in PhysicsAre they always saying “must try harder”?

  17. We don’t have any trustworthy theory of what happened at t < 10-43s

  18. Late-time Acceleration

  19. A Big Mystery Why isn’t   10+66 cm-2 We observe obs  10-55 cm-2 ???? No galaxies if  > 10-54 cm-2

  20. The Return of Lambda ? H2 =8G/3 – k/a2 + /3 1 = M + k +  where M = 8G/3H2 k = – k/a2H2  = /3H2

  21. Or is dark energy a time-changing version of lambda? W p/ = wo + wa(1 – a) assumed for an evolving dark energy Simple cosmological constant model is wo = -1 and wa = 0

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