On the Origin of Structure in the Universe
- 1. Daniel Baumann University of Amsterdam On the Origin of Structure in the Universe Inaugural Lecture
- 5. Sloan Digital Sky Survey
- 6. Where did it all come from?
- 7. The answer involves a fascinating connection between the physics of the very small and the very large:
- 8. Plan of the Talk Quantum Origin Structure Formation Future Prospects Thank You’s
- 9. Disclaimer: This talk was written for my parents …
- 11. The First Light 380,000 years after the Big Bang, the first atoms formed and light was released from the cosmic fireball: The variations in the intensity of the light correspond to variations in the density of the primordial matter.
- 12. 380,000 years 13.8 billion years The Rich Are Getting Richer These small density fluctuations grew over time and became the structures we see around us: galaxies, stars, planets, …
- 13. Where Did It All Come From? We have reasons to believe that the initial fluctuations were created just fractions of a second after the Big Bang. ? 380,000 years 13.8 billion years 10-32 sec
- 14. ? A Detective Story To learn about this time in the history of the universe, we must decode the pattern of fluctuations in the afterglow of the Big Bang.
- 15. Correlated, Not Random We have discovered that these fluctuations aren’t just random noise, but are correlated over large distances. two-point correlation angular separation 90 1 0.1
- 16. A Clue In fact, the fluctuations are found to be correlated over distances that are larger than the distance light travelled since the Big Bang: distance light travelled since the Big Bang This seems to be in conflict with causality. observable universe
- 17. Inflation 10-32 sec = 0.00000000000000000000000000000001 seconds This can be explained if the early universe expanded faster than light, doubling in size at least 80 times within a fraction of a second:
- 18. Inflation 10-32 sec = 0.00000000000000000000000000000001 seconds This can be explained if the early universe expanded faster than light, doubling in size at least 80 times within a fraction of a second:
- 19. The entire observable universe originates from a microscopic, causally connected region of space: Subatomic scales get stretched to cosmological scales. From Micro To Macro
- 20. Quantum Origin
- 21. Empty Space Isn’t Empty
- 22. Empty Space Isn’t Empty
- 23. These vacuum fluctuations are real, but usually have very small effects: Empty Space Isn’t Empty Lamb shift
- 24. The correlations observed in the afterglow of the Big Bang are inherited from the correlations of the quantum fluctuations. From Micro To Macro During inflation, these quantum fluctuations get amplified and stretched:
- 25. It Works! The predicted correlations are in remarkable agreement with the data: There is growing evidence that something like inflation must have occurred, but the physics of inflation remains a mystery.
- 26. The inflationary expansion requires a substance with nearly constant energy density: Vacuum Energy
- 27. Like for a radioactive substance, the inflationary energy in each region of space has a small probability to decay: Vacuum Decay
- 28. One of these bubbles is our universe Vacuum Decay
- 29. Due to quantum uncertainty, the decay inside each bubble will not be exactly simultaneous, creating the density fluctuations after inflation: Quantum Fluctuations
- 30. Models of Inflation Inflationary models are distinguished by • the source of vacuum energy • the rate of vacuum decay • the types of correlations
- 31. A Landscape of Models A lot of work has gone into mapping out the space of inflationary models: landscape slow-roll inflation large-field inflation DBI inflation brane inflation multi-field inflation axion inflation
- 32. Landscape vs Swampland Some models seem incompatible with basic principles of quantum gravity. These models are said to live in the swampland. landscape swampland global symmetries superluminal propagation gravity is not the weakest force
- 33. Landscape vs Swampland Some models seem incompatible with basic principles of quantum gravity. These models are said to live in the swampland. landscape swampland Which theories are consistent with observations? global symmetries superluminal propagation gravity is not the weakest force
- 34. Future Prospects
- 35. How can inflation become part of the standard history of the universe with the same level of confidence as BBN ?
- 36. Primordial Gravitational Waves The strength of the signal depends on the energy scale of inflation, which may be as high as 1016 GeV. Inflation predicts ripples in spacetime = gravitational waves (GWs):
- 37. Primordial Gravitational Waves Inflationary models with observable GWs live at the boundary of the swampland. On which side is a subject of very active debate. swampland landscape GWs A detection would be a spectacular discovery.
- 38. LIGO detected GWs with wavelengths of order thousands of kilometers The GWs produced by inflation have wavelengths of order billions of light-years. How do we detect them?
- 39. B-modes The presence of gravitational waves during the formation of the first atoms leads to a swirl pattern in the polarization of the first light:
- 40. The Hunt for B-modes Detecting gravitational waves from inflation is the holy grail of modern observational cosmology: Atacama Desert South Pole
- 41. Primordial Interactions The strength of these higher-point correlations depends on the type of substance that created inflation and its interactions. Inflation also predicts correlations between more than just two points:
- 42. Quantum fluctuations during inflation can produce very massive particles whose decays lead to higher-order correlations: Primordial Interactions
- 43. Some interactions cannot arise from a consistent quantum theory of gravity and therefore live in the swampland: Primordial Interactions swampland landscape < 0 A detection would teach us a lot about the origin of the inflationary expansion.
- 44. LSS 21cm CMB Future observations will map out density fluctuations over the entire observable universe: This allow us to search for the subtle imprints of primordial interactions. The Hunt for Non-Gaussianity
- 45. Where Did It All Come From? 380,000 years 13.8 billion years 10-32 sec
- 46. Cosmology in Amsterdam String theory GRAPPA Cosmology http://cosmology.amsterdam
- 47. A Few Thank You’s
- 48. Mentors Paul Steinhardt Liam McAllister Matias Zaldarriaga
- 49. Collaborators Daniel Green Amin, Arkani-Hamed, Assassi, Beutler, Bird, Chia, Cooray, Dymarsky, Ferraro, Flauger, Friedman, Goon, Hartman, Huterer, Ichiki, Kachru, Kamionkowski, Klebanov, Lee, Maldacena, McAllister, Meyers, Murugan, Nicolis, Pajer, Peiris, Pimentel, Porto, Sarkar, Schmidt, Senatore, Serra, Sigurdson, Slosar, Smith, Steinhardt, Stout, Takahashi, Turok, Vargas- Magana, Wallisch, Welling, van der Woude, Yeche, Zaldarriaga
- 50. Students Valentin Assassi Hayden Lee Benjamin Wallisch Carlos Duaso Pueyo Horng Sheng Chia Lotte ter Haar
- 51. Research Group
- 52. Colleagues
- 53. Colleagues
- 54. Family
- 57. Family
- 58. Bedankt voor uw aandacht