1. George E. A. Matsas Instituto de Física Teórica/ Unesp Search for low-energy semi-classical gravity effects

2. Challenges of new physics in space for quantum gravity  Is the big bang a true singularity?  What is the physics of super-hot universe: T> 10 19 GeV?  Is dark energy a (low-energy) quantum gravity effect?  Do black holes really evaporate? (transplanckian modes issue)  What is the final stage of black hole evaporation?  Is there any black hole information paradox?  Are there naked singularities and are they really “singular”?  Can quantum gravity fool the cosmic censor? ...

3. What is Quantum Gravity? C. Rovelli, “Notes for a brief history of Quantum Gravity”, gr-qc/0006061 NOBODY NOWS

4. Necessary condition: Quantum Gravity includes observables which depend simultaneously on c, h and G (in CGS units). Quantum gravity effect space Complexity (# of parameters) Energy Semiclassical gravity regime Full quantum gravity regime

5. Semiclassical gravity regime Full quantum gravity regime Semiclassical gravity (quantum field theory in curved spacetimes + backreaction effects) Globally hiperbolic spacetimes

6. Stanford Linear Accelerator Center cortesy Hawking effect (Nature 248(1974)30) Semiclassical gravity regime Full quantum gravity regime

7. Stanford Linear Accelerator Center cortesy Unruh effect (Phys. Rev. D 14(1976)870) D. Vanzella, GEAM, Phys.Rev.Lett. 87 (2001) 151301 Semiclassical gravity regime Full quantum gravity regime Elementary particle concept Crispino, GEAM, Higuchi, Rev.Mod.Phys. 80(2008)787

8. Semiclassical gravity regime Full quantum gravity regime Unruh effect Hawking effect “Go slow to arrive the soonest” Old physics on Earth helps new physics in space

9. Sonic holes (Unruh, Phys. Rev. D 46(1981)1351) Problem: Transplanckian modes Solution(?): Is the spacetime like a fluid? Question: Do we loose Lorentz invariance at Planck scale? Semiclassical gravity regime Full quantum gravity regime hydrodynamics

10. Cosmic Censorship Conjecture Weak Cosmic Censorship Conjecture If one starts out with an initially non-singular asymptotically flat situation, any singularities which subsequently develop due to gravitational collapse will be hidden from the view of an observer at infinity by the event horizon of a black hole (Penrose, Nuovo Cimento 1969) unpredictable Naked singularities are so imoral that there may exist cosmic censors to dress them all (but the big bang) with event horizons. Semiclassical gravity regime Full quantum gravity regime Particle physics

11. ANTI-Cosmic Censorship Conjecture Because quantum gravity should unveil the physics of naked singularities and recover the predictability of the Universe, there must exist anti-cosmic censors guarantying the existence of naked-singularity quantum generation mechanisms Made predictable by quantum mechanics

12. time (Choptuik, PRL 1993) Naked singularity SPECIAL initial conditions Naked singularity from matter collapse?

13. time GENERIC initial conditions Naked singularity from matter collapse?

14. Black Holes and Naked Singularities Question: Is it possible to overspin or overcharge a black hole stripping bare a black hole to reveal its singularity?

15. Throwing a classical particle into an extreme black hole ( Wald, Ann. Phys. 74) Gravitational Potential particle For related work with further developments see “Overcharging a black hole and cosmic censorship”. (Hubeny, PRD 99)

16. (G.E.A.M. & A.R.R. da Silva, Phys. Rev. Lett 2007) [comments also in Nature, 450, 147 (2007)] particle Gravitational Potential Overspinning a charged black hole via quantum tunneling?

17. The backreaction issue (Hod, PRL 2008) (GEAM, Richartz, Saa, da Silva, Vanzella, submitted to publication) (Richartz & Saa, PRD 2008)

18. Quantum Gravity final veredictum

19. Generalized second law Generalized second law

20. Naked singularity/elementary particle conjecture Naked singularity/elementary particle conjecture

21. This is time to reflect on how risky our bets towards Quantum Gravity should be