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Vacuum Energy & Cosmology: �Theory & Observations �(with a Historical Perspective)

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Emilio Elizalde

National Research Council of Spain

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Institut de Ciències de l’Espai (ICE/CSIC)

Institut d’Estudis Espacials de Catalunya (IEEC)

Campus Universitat Autònoma de Barcelona (UAB)

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Leiden CASIMIR Workshop, March 2012

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  • 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, 1786-1802, a total of 2510 nebulae

  • And then, Edwin Hubble, in 1922-1924, 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

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Henrietta Leavitt

Ed Pickering’s Harvard Harem

… or Harvard Computers

1913

Mittag-Leffler

NP proposal ‘26

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  • 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, 1912 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 1931-37)
  • A Riess B Schmidt ’98, S Perlmutter ’99: acceler expan!

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Friedmann equation (matter,radiation,curvature)

Multiply by a2 to get

When a increases, each term on rhs decreases:

the universe should be decelerating (a decreases)

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a

t

Big Bang

Sean Carroll, Caltech

SSI 2009

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Two groups looked for the ‘deceleration’ of the universe expansion, using type Ia supernovae

as standardizable candles

SN 1994d

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Result: supernovae are

dimmer than expected

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The universe is not

decelerating

It is accelerating

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Cannot be explained by matter+radiation (see before)

Riess, Schmidt et al. ‘98 Perlmutter et al. ‘99

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��Some�Books��

2nd Ed June 2012

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��Thank You ��Dank je wel��