1. Vacuum Energy & Cosmology: Theory & Observations (with a Historical Perspective)
Emilio Elizalde
National Research Council of Spain
Institut de Ciències de l’Espai (ICE/CSIC)
Institut d’Estudis Espacials de Catalunya (IEEC)
Campus Universitat Autònoma de Barcelona (UAB)
Leiden CASIMIR Workshop, March 2012

3. But... the Universe was static !! (…and very small)
What is λ ? Non-physical
At that time: UNIVERSE = MILKY WAY (+ nebulae)
Ptolemy 150 DC, Almagest: mentions 5 nebulae
Persian, Arabic, Chinese astronomers: more nebulae
Edmund Halley 6 in 1715, Charles Messier 103 in 1781
William and Caroline Herschel 3 catalogs, , a total of 2510 nebulae
And then, Edwin Hubble, in , saw Andromeda nebulae (.8 Mly) was far beyond our Milky Way: nebulae were other galaxies!
Henrietta S Leavitt (Ed Pickering’s Harvard Harem), ‘12 period-luminosity relationship of Cepheid variable stars (Eddington , He+,++) Hertzsprung-Russell Diagramm

4. Ed Pickering’s Harvard Harem
Henrietta Leavitt
Mittag-Leffler
NP proposal ‘26
Ed Pickering’s Harvard Harem
1913
… or Harvard Computers

8. Karl Schwarzschild: Black Hole solution (22 Dec 1915)
Willem de Sitter: massless univer static sol (just cc,’17)
Alexander Friedmann: expanding universe sol (1922)
Georges Lemaître: expanding universe (MIT 1925, AF solution); visited Vesto Slipher (Lowell Obs, Arizona, redshifts) and Edwin Hubble (Mount Wilson, Pasadena); Keeler-Slipher-Campbell, 1918
Led to Big Bang theory (Fred Hoyle, BBC radio 3rd Programme, 18:30 GMT, 28 March 1949)
Fred Hoyle, Thomas Gold, Hermann Bondi: SteadyState ’48, “C-field” with a negative pressure, to be consistent with energy conservation (anticipated inflation)
Friedmann-Lemaître-Robertson-Walker (FLRW )
A Riess B Schmidt ’98, S Perlmutter ’99: acceler expan!

9. Friedmann equation (matter,radiation,curvature)
Multiply by a2 to get a
When a increases, each term on rhs decreases:
the universe should be decelerating (a decreases) .
Sean Carroll, Caltech
SSI 2009
Big Bang t

10. as standardizable candles
Two groups looked for the ‘deceleration’ of the universe expansion, using type Ia supernovae
as standardizable candles
SN 1994d

11. Result: supernovae are dimmer than expected The universe is not
decelerating
It is accelerating
Cannot be explained by matter+radiation (see before)
Riess, Schmidt et al. ‘98 Perlmutter et al. ‘99

26. Some Books
2nd Ed June 2012

27. Thank You Dank je wel