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Centro de Astrofísica da Universidade do Porto

Astrophysical tests of fundamental physics

Carlos J. A. P. Martins

The dramatic confrontation between new observations and theories of the early and recent universe makes cosmology one of the most rapidly advancing fields in the physical sciences. The universe is a unique laboratory in which to probe fundamental physics, the rationale being to start from fundamental physics inspired models and explore their consequences in sufficient quantitative detail to be able to identify key astrophysical and cosmological tests of the underlying theory (or developing new tests when appropriate). An unprecedented number of such tests will be possible in the coming years, by exploiting the ever improving observational data.

This course will present some recent developments in this field, highlight the current hot topics and open issues, and suggest future research directions - in particular, those that the group may fruitfully exploit. An outline schedule is as follows

  • Introduction: the standard model
  • Unification and extra dimensions
  • The Equivalence Principle
  • Scalar fields, dynamical dark energy and varying constants
  • Laboratory and local tests
  • Astrophysical probes
  • Cosmological probes
  • Future ESO and ESA plans

A reading list will be provided in October. Most of the course should be accessible to masters students and to high-level undergraduates.

Sessão 1: Introduction - The Standard Model
4 novembro 2009

In the first lecture I will highlight the key fundamental physics paradigms that will be probed in the coming years.

I'll start by briefly discussing the 'cosmic concordance' model and the current hints for new physics. I will then review the motivation for unification, extra dimensions and the Higgs mechanism, and I will also comment on how these can be probed at the LHC. Finally I will present the physical concepts and some tests of the various Equivalence Principles.

The following may be useful as supplementary reading:

Sessão 2: Phenomenology
11 novembro 2009

The second lecture will focus on phenomenological models, which aim to capture the broad fundamental aspects of fundamental theories while being specific enough to be tested observationally.

I will start with a brief description of the possible roles of scalar fields in cosmology. I will comment on the challenges of obtaining inflationary models from string and then discuss the role of fundamental constants in physical theories, emphasizing the links with dark energy.

Finally I will present a brief tutorial on models for time and spatial variations of the fundamental constants.

The following may be useful as supplementary reading:

Sessão 3: The Astrophysical Controversy
18 novembro 2009

In this lecture I will review the current status of experimental and observational searches for varying fundamental constants.

After a brief discussion of local experiments with atomic clocks I will focus on the current controversy surrounding astrophysical measurements involving quasar absorption systems, where unconfirmed claims of variations exist both for the fine-structure constant and the proton-to-electron mass ratio. I will also highlight recent work wich aims to resolve the controversy by providing a 'gold standard' for this type of analysis. Finally I will also discuss searches in the radio band and measurements using the cosmic microwave background and nucleosynthesis.

The following may be useful as supplementary reading:

Sessão 4: Cosmological Implications
25 novembro 2009

In the final lecture I will highlight some cosmological implication of varying fundamental constants measurements, focusing on their relation to dynamical dark energy. I will also discuss tests of the global dynamics of the universe, particularly the Sandage-Loeb test. Finally, I will describe prospects for future improvements in this context, focusing on ESPRESSO and CODEX.

The following may be useful as supplementary reading: