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The Universe

September 4, 2009. The Universe. Piet Mulders. http://www.nat.vu.nl/~mulders. mulders@few.vu.nl. The universe. Introduction Basic concepts Structure of Matter The fundamental forces Symmetry The history of the universe Open questions … and where to find the answers. home.

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The Universe

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  1. September 4, 2009 The Universe Piet Mulders http://www.nat.vu.nl/~mulders mulders@few.vu.nl

  2. The universe • Introduction • Basic concepts • Structure of Matter • The fundamental forces • Symmetry • The history of the universe • Open questions … and where to find the answers

  3. home Introduction http://www.nat.vu.nl/~mulders P.J. Mulders

  4. Big Bang – History of Universe • Our vision of ultimate evolution based on (known!) concepts • (Amazingly) good agreement! • Cosmic Microwave Background (CMB) as proof

  5. Physics2006 • John C. Mather (1946) NASA Goddard Space Flight Center, Greenbelt, MD, USA (PhD from Berkeley) • George F. Smoot (1945) University of California, Berkeley, CA, USA (PhD from MIT)

  6. for … For their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation From www.nobel.se: The Nobel Prize in Physics 2006 has been awarded to U.S. physicists John Mather (NASA) and George Smoot (LBL) for their discovery of the basic form of the cosmic microwave background radiation as well as its small variations in different directions. The very detailed observations that the laureates have carried out from the COBE satellite have played a major role in the development of modern cosmology into a precise science.

  7. Measuring temperatures in the universe Looking at the color (maximum of light emission) or more general to the form of the emission spectrum These emission shapes can also be created in a lab and were first described by Max Planck (Nobel prize 1918)

  8. History of the CMB • Expanding universe (Friedmann 1922, Lemaitre 1927, Willem de Sitter) and redshift (Edwin Hubble 1929) • Richard Tolman (working with Hubble) showed in 1934 that cooling blackbody radiation in an expanding universe retains its form • Prediction of Cosmic Background Radiation (George Gamov 1948; Ralph Alpher and Robert Herman 1950) • Accidental observation of Cosmic Microwave Background (CMB) at Bell Labs by Arno Penzias & Robert Wilson 1965 (Nobel prize 1978) • Robert Dicke, Peebles, Roll and Dave Wilkinson 1965 realized immediately that CMB had been found! Origin of the CMB

  9. 13.7 billion years ago BIG BANG

  10. Big Bang – History of Universe • Our vision of ultimate evolution based on (known!) concepts • (Amazingly) good agreement! • Cosmic Microwave Background (CMB) as proof • Theory/understanding of space-time • Underlying symmetries • Consistent set of forces

  11. home Basic concepts http://www.nat.vu.nl/~mulders P.J. Mulders

  12. Space-time • We live in a 3+1 dimensional space (possibly embedded in a higher-dimensional space in which a number of dimensions are ‘compactified’ and/or are only relevant at extreme scales) • Basic symmetry: invariance under Poincaré transformations • Concepts Energy, momentum, angular momentum • Notion of degrees of freedom position, time, particles/waves, observables, …

  13. Poincaré symmetry • Physical laws are invariant under • Translations in space ant time • Rotations • Boosts (change to a reference frame moving with a constant velocity) • Forces break the ‘constant velocity’ and equations of motion describe what is happening with particular degrees of freedom (F = m a) • Symmetries imply certain quantities to be conserved: • Time translations: conservation of energy • Space translations: conservation of momentum • Rotations: conservation of angular momentum

  14. INLEIDING light big small heavy The (theoretical) framework Relativistic quantum mechanics Special relativity velocity: v = p c2/E Classical mechanics Quantum mechanics 0 ђ Action: E t ~ p r ~ ℓ

  15. home The structure of matter http://www.nat.vu.nl/~mulders P.J. Mulders

  16. Materie MATTER

  17. Materie MATTER ELECTRON ATOM 10-10 m

  18. The periodic table

  19. MATTER MATTER MATTER ELECTRON ELECTRON ELECTRON ATOM 10-10 m ATOM 10-10 m ATOM 10-10 m NEUTRINO NEUTRINO NUCLEUS 10-14 m NUCLEUS 10-14 m NUCLEON proton/neutron 10-15 m Materie

  20. Atomic nuclei Island of stability

  21. Atomic nuclei • Isotopes • Radioactivity alpha beta gamma after 15 min.

  22. more on neutrinos Neutrino’s

  23. Building blocks of the subatomic world

  24. MATTER MATTER ELECTRON ELECTRON ATOM 10-10 m ATOM 10-10 m NEUTRINO NEUTRINO NUCLEUS 10-14 m NUCLEUS 10-14 m NUCLEON proton/neutron 10-15 m NUCLEON proton/neutron 10-15 m QUARK up/down Materie

  25. home Basic building blocks of matter Really down to bits! 1079 electrons in the Universe

  26. home How do we know this? http://www.nat.vu.nl/~mulders P.J. Mulders

  27. By using the largest microscopes on Earth

  28. Antiparticles

  29. Standard model content • 3 particle families

  30. home The fundamental forces http://www.nat.vu.nl/~mulders P.J. Mulders

  31. Forces in daily life • Two of four basic forces • Both based on fundamental principles • Electromagnetism • Gravity

  32. more on gravity Standard model • 3 particle families • 4 fundamental forces • strong force • quark  nucleon  atomic nucleus • electromagnetic force • atom  molecule  complexity • weak force • decay • gravity UNIFICATION

  33. Standard model • 3 particle families • 4 fundamental forces • Corresponding force particles And a consistent theoretical framework: a renormalizable non-abelian gauge theory Steven Weinberg Sheldon Glashow Abdus Salam Gerard ‘t Hooft Martinus Veltman

  34. Example: neutron decay Neutron beta-decay n  p + e- + ne At the quark level d  u + e- + ne

  35. How do quarks and gluons give the proton its properties? A one-line theory: QCD Massless quarks and gluons Protons and neutrons: Basic constituents of atomic nuclei forming 99.5 % of the visible mass in the universe

  36. u d u u d d Mass of nucleon • Almost massless quarks: mu ~ 5 MeV and md ~ 10 MeV • constant force T0 = 1 GeV/fm leads to confinement of color over distances of ~ 0.8 fm Pressure in bubble: B ~ 100 MeV/fm3  EV = 4pBR3/3 ~ 200 MeV • Momentum p ~ 1/R ~ 250 MeV • Energy per quark: EQ ~ 250 MeV • Total energy: E ~ 940 MeV = mass of nucleon proton neutron

  37. home Central theme of standard model:SYMMETRY http://www.nat.vu.nl/~mulders P.J. Mulders

  38. Mirror symmetry • Mirror world? • Example: top • Mirror world exist • Conclusion: mirror symmetry is a symmetry of our daily world

  39. mirror images righthanded Broken mirror symmetry For neutrinos there exist nL but not nR • A pion decays into spinning particles • For a neutrino only one spin direction exist! • But how can we measure this? • spin + charge  magnet • Only m+ observed at N-pole of the magnet! lefthanded

  40. _ _ _ K0 = ds, K0 = sdhave slightly different masses and decay in a different way CP symmetry • Mirror symmetry (P) is broken in the subatomic world • Particle-antiparticle symmetry (C) is also broken • But … the combination is indeed a symmetry almost

  41. CPT symmetry

  42. more on mass in universe Time reversal • CPT is (to our present knowledge!) indeed a good symmetry of the world • CP is almost a good symmetry • Thus also time reversal is almost a good symmetry, but not exact! • This symmetry breaking allows for the surplus of matter over antimatter in the universe (even if this is only 1 : 109) Number of baryons  0,25 x 1079 (~ 0,25 per m3) But the number of photons and neutrinos  1088 (~ 400 per cm3)

  43. CP-violation in standard model CP-violation can be implemented in the standard model through complex phase(s) in CKM-matrix. This requires at least three families! Cabibbo Kobayashi Maskawa

  44. home The history of the universe http://www.nat.vu.nl/~mulders P.J. Mulders

  45. 13.7 billion years ago BIG BANG

  46. inflation

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