1. Quantum Gravity: Infinities, Loops, and Strings Vsevolod Ivanov2014 What is THE question (and why do we care)? A quantum history The trouble with gravity SUGRA, almost sugar but not as sweet A tale of two revolutions Loopy nets Experimentalists flex their muscles The future?

2. Quantum Gravity: Infinities, Loops, and Strings What is THE question (and why do we care)? A quantum history The trouble with gravity SUGRA, almost sugar but not as sweet A tale of two revolutions Loopy nets Experimentalists flex their muscles The future?

3. Introduction Gravitation and three other fundamental forces have non-compatible formalism Each breaks down outside its domain Quantized theory of gravity is desired Secondary goal: “theory of everything”

4. Quantum Gravity: Infinities, Loops, and Strings What is THE question (and why do we care)? A quantum history The trouble with gravity SUGRA, almost sugar but not as sweet A tale of two revolutions Loopy nets Experimentalists flex their muscles The future?

5. Quantum Gravity: Infinities, Loops, and Strings What is THE question (and why do we care)? A quantum history The trouble with gravity SUGRA, almost sugar but not as sweet A tale of two revolutions Loopy nets Experimentalists flex their muscles The future?

6. Quick Review of Feynman Diagrams

7. QED in d Dimensions

8. Field Theory for Gravity

9. Mass Dimension of the Coupling Constant

10. Quantum Gravity: Infinities, Loops, and Strings What is THE question (and why do we care)? A quantum history The trouble with gravity SUGRA, almost sugar but not as sweet A tale of two revolutions Loopy nets Experimentalists flex their muscles The future?

11. SUper GRAvity

12. Quantum Gravity: Infinities, Loops, and Strings What is THE question (and why do we care)? A quantum history The trouble with gravity SUGRA, almost sugar but not as sweet A tale of two revolutions Loopy nets Experimentalists flex their muscles The future?

13. SUper GRAvity

14. Quantum Gravity: Infinities, Loops, and Strings What is THE question (and why do we care)? A quantum history The trouble with gravity SUGRA, almost sugar but not as sweet A tale of two revolutions Loopy nets Experimentalists flex their muscles The future?

15. Loop Quantum Gravity

16. Quantum Gravity: Infinities, Loops, and Strings What is THE question (and why do we care)? A quantum history The trouble with gravity SUGRA, almost sugar but not as sweet A tale of two revolutions Loopy nets Experimentalists flex their muscles The future?

17. Experimental Tests of Quantum Gravity Quantum gravitational effects are too weak to test! Recent proposals: QG effects in gamma ray bursts Violation of Lorentz invariance Polarization of the CMB

18. CMB Polarization Temperature creates quadrupole anisotropy Other effects: Density fluctuations (scalar) Vorticity from defects (vector), damped out by inflation Gravitational waves (tensor) Two Polarization Types: Curl-free E-mode and Grad-free B-mode

19. BICEP 2 Measures B-mode Polarization!

20. Quantum Gravity: Infinities, Loops, and Strings What is THE question (and why do we care)? A quantum history The trouble with gravity SUGRA, almost sugar but not as sweet A tale of two revolutions Loopy nets Experimentalists flex their muscles The future?

21. Future Experimental Tests Lorentz invariance violation: future experiments will have better precision for higher order terms Planck probe will measure anisotropies to higher precision GW-superconductor interactions?

22. References “Quantum Gravity Notes” M. Spiropilu (2004) "Cosmic Microwave Background Polarization: The Next Key Toward the Origin of the Universe", Y. D. Takahashi "Angular momentum: an approach to combinatorial space-time", R. Penrose "Introduction to Loop Quantum Gravity", Simone Mercuri "Quantum gravity: an introduction to some recent results", Enrique Alvarez "Detection of B-Mode Polarization in the Cosmic Microwave Background with Data from the South Pole Telescope", D. Hanson et al., PRL 111, 141301 (2013) "Experimental Search for Quantum Gravity", Sabine Hossenfelder An Introduction to Modern Astrophysics, B.W. Carroll, D. A. Ostlie (1996) Images: http://astrophysics.pro/wp-content/uploads/2013/03/Quantum-Gravity.jpg http://upload.wikimedia.org/wikipedia/commons/d/d2/Spinnetwork.jpg Questions?