Codello Minicourse on Effective Field Theory of Gravity

Dates: March 13-24, 2017

Lecturer: Alessandro Codello (CP3 – Origins, Odense, Denmark)

Place: Room 3 – IFT-UNESP

Times:

March 13 – Monday - 2 pm

March 14 – Tuesday – 10:30

March 16 – Thursday – 10:30

March 20 – Monday - 2 pm

March 21 – Tuesday – 10:30

March 23 – Thursday – 10:30

**Description:**

The effective field theory (EFT) of gravity is a perfectly well-defined and predictive quantum field theory, valid below the Planck scale. Its status is comparable to that of the Standard Model, which in the absence of “new physics” is also expected to break down at some UV scale.

The smallness of the quantum gravitational effects is the result of the wide separation between the scale of current experiments and the “scale of new physics”, which is represented by the Planck scale. No other EFT is characterized by a that large separation of scales which implies a very small expansion parameter. In this sense one could paradoxically say that the EFT of gravity is the best perturbative quantum field theory (QFT). It has certainly a very broad range of applicability and leads to unique and well defined predictions which can be computed from first principles even in the absence of a complete theory of quantum gravity. In these lectures, after briefly reviewing the path integral quantization of the QFT of gravity and the failure of perturbative renormalizability, we will introduce the EFT approach. We will use covariant heat kernel techniques to compute both the divergent and finite parts of the gravitational effective action on arbitrary spacetimes. As a first application we will show how to compute the leading corrections to the Newtonian potential. In a second application we will see some cosmological implications, such as the possibility of unifying inflation and dark energy within the EFT approach.

A “Certificate of Attendance” will be offered to those participants with 100% of attendance to the lectures.

*There will be no application form for this activity and everyone is welcome to participate. For more information, send email to secretary@ictp-saifr.org .*

**Program:**

**Lecture 1: QFT of gravity**

- Path integral quantization and background field method

- Heat kernel expansion and UV divergencies

- Failure of perturbative renormalizability

**Lecture 2: The EFT of gravity**

- Predictivity in quantum gravity

- The effective action within the EFT of gravity

**Lecture 3: Corrections to the Newtonian potential**

- The finite part of the effective action via non-local heat kernel expansion

- The leading corrections to the Newtonian potential

**Lecture 4: Unified evolution of the Universe**

- Cosmological effective action from the EFT

- Non-local gravity and effective Friedmann equations

**Lecture 5: Unified evolution of the Universe**

- A gravitational model unifying inflation and dark energy