1. Outstanding Problems in Cosmology
Conclusions
Outstanding Problems in Cosmology
for the Next 20 Years
ICGC 2015,
IISER Mohali
December 14-18, 2015

2. We do not know the physical nature of ~ 95% of the stuff that makes
Dark Matter & Dark Energy
We do not know the physical nature of ~ 95% of the stuff that makes
our Universe

3. We do not know the physical nature of ~ 95% of the stuff that makes
Dark Matter & Dark Energy
We do not know the physical nature of ~ 95% of the stuff that makes
our Universe
Is there new type of energy (WIMP, Quintessence) or is it modified
gravity (MOND, DGP)?

4. We do not know the physical nature of ~ 95% of the stuff that makes
Dark Matter & Dark Energy
We do not know the physical nature of ~ 95% of the stuff that makes
our Universe
Is there new type of energy (WIMP, Quintessence) or is it modified
gravity (MOND, DGP)?
A fundamental problem in Physics: the CC problem or what are the
gravitational properties of the vacuum??

5. 1) Are we sure it is inflation?
Inflation & Early Universe
1) Are we sure it is inflation?

6. 1) Are we sure it is inflation?
Inflation & Early Universe
1) Are we sure it is inflation?
No, but it looks very likely. A smoking gun would be to verify the
consistency checks

7. Are we sure it is inflation?
Inflation & Early Universe
Are we sure it is inflation?
Which is the inflaton field?

8. Are we sure it is inflation?
Inflation & Early Universe
Are we sure it is inflation?
Which is the inflaton field?
Can we consistently embed inflation in high energy physics?
HEP seems complicated so why vanilla inflation seems to emerge from the data (so far …)?
UV sensitivity of inflation: problem or window of opportunity?

9. Are we sure it is inflation?
Inflation & Early Universe
Are we sure it is inflation?
Which is the inflaton field?
How did inflation come to an end and can it be probed observationally?

10. Are we sure it is inflation?
Inflation & Early Universe
Are we sure it is inflation?
Which is the inflaton field?
How did inflation come to an end and can it be probed observationally?
How did inflation start? Is it eternal?

11. Are we sure it is inflation?
Inflation & Early Universe
Are we sure it is inflation?
Which is the inflaton field?
How did inflation come to an end and can it be probed observationally?
How did inflation start? Is it eternal?
If we see non-minimal features, can we prove that they come to more
complicated models of inflation?

12. Are we sure it is inflation?
Inflation & Early Universe
Are we sure it is inflation?
Which is the inflaton field?
How did inflation come to an end and can it be probed observationally?
How did inflation start? Is it eternal?
If we see non-minimal features, can we proove that they come to more
complicated models of inflation?
K-inflation
Multiple field inflation

13. Are we sure it is inflation?
Inflation & Early Universe
Are we sure it is inflation?
Who is the inflaton field?
How did inflation come to an end and can it be probed observationally?
How did inflation start? Is it eternal?
If we see non-minimal features, can we proove that they come to more
complicated models of inflation?
6) Can we learn something about Quantum Mechanics?

14. Are we sure it is inflation?
Inflation & Early Universe
Are we sure it is inflation?
Which is the inflaton field?
How did inflation come to an end and can it be probed observationally?
How did inflation start? Is it eternal?
If we see non-minimal features, can we proove that they come to more
complicated models of inflation?
6) Can we learn something about Quantum Mechanics?
Inflation is the only situation in Physics where you need GR, QM and you have high accuracy measurements (the closest situation would be the Colella-Overhauser-Werner –COW- experiment).

15. How to proceed?
1) B-modes

16. If r>0.01, we should know it in the coming 5 years
How to proceed?
1) B-modes
- We do not know where the signal is (~ SUSY in HEP) but feasible if r>0.001
If r>0.01, we should know it in the coming 5 years
- Knowing r is very efficient for model selection
Given that r<0.07, verifying the consistency check seems already hopeless …
Maybe r<0.001 …

17. How to proceed?
B-modes
Non-Gaussianities

18. or feasible? If we do not find NG at this level, it is a revolution!
How to proceed?
B-modes
Non-Gaussianities
A priori, we know where the signal is (~ Higgs boson) but is it realistic
or feasible? If we do not find NG at this level, it is a revolution!
Maybe the NG is of order one … it would then point to more complicated
models of inflation (multi field, features etc …)

19. Direct detection of inflationary gravitational waves
How to proceed?
B-modes
Non-Gaussianities
Direct detection of inflationary gravitational waves

20. Direct detection of inflationary gravitational waves
How to proceed?
B-modes
Non-Gaussianities
Direct detection of inflationary gravitational waves
- Is it realistic …??
- Also important for reheating!

21. Direct detection of inflationary graviatational waves
How to proceed?
B-modes
Non-Gaussianities
Direct detection of inflationary graviatational waves
Somehting else …??? To be discussed …