Effective Field Theory and Finite Density Systems

This review gives an overview of effective field theory (EFT) as applied at finite density, with a focus on nuclear many-body systems. Uniform systems with short-range interactions illustrate the ingredients and virtues of many-body EFT and then the varied frontiers of EFT for finite nuclei and nuclear matter are surveyed.Comment: 27 pages, 5 figure

Nonlinear Sigma Model for Disordered Media: Replica Trick for Non-Perturbative Results and Interactions

In these lectures, given at the NATO ASI at Windsor (2001), applications of the replicas nonlinear sigma model to disordered systems are reviewed. A particular attention is given to two sets of issues. First, obtaining non-perturbative results in the replica limit is discussed, using as examples (i) an oscillatory behaviour of the two-level correlation function and (ii) long-tail asymptotes of different mesoscopic distributions. Second, a new variant of the sigma model for interacting electrons in disordered normal and superconducting systems is presented, with demonstrating how to reduce it, under certain controlled approximations, to known ``phase-only'' actions, including that of the ``dirty bosons'' model.Comment: 25 pages, Proceedings of the NATO ASI "Field Theory of Strongly Correlated Fermions and Bosons in Low - Dimensional Disordered Systems", Windsor, August, 2001; to be published by Kluwe

From Luttinger to Fermi liquids in organic conductors

This chapter reviews the effects of interactions in quasi-one dimensional systems, such as the Bechgaard and Fabre salts, and in particular the Luttinger liquid physics. It discusses in details how transport measurements both d.c. and a.c. allow to probe such a physics. It also examine the dimensional crossover and deconfinement transition occurring between the one dimensional case and the higher dimensional one resulting from the hopping of electrons between chains in the quasi-one dimensional structure.Comment: To be published In the book "The Physics of Organic Conductors and Superconductors", Springer, 2007, ed. A. Lebe

Ultracold atomic gases in optical lattices: mimicking condensed matter physics and beyond

We review recent developments in the physics of ultracold atomic and molecular gases in optical lattices. Such systems are nearly perfect realisations of various kinds of Hubbard models, and as such may very well serve to mimic condensed matter phenomena. We show how these systems may be employed as quantum simulators to answer some challenging open questions of condensed matter, and even high energy physics. After a short presentation of the models and the methods of treatment of such systems, we discuss in detail, which challenges of condensed matter physics can be addressed with (i) disordered ultracold lattice gases, (ii) frustrated ultracold gases, (iii) spinor lattice gases, (iv) lattice gases in "artificial" magnetic fields, and, last but not least, (v) quantum information processing in lattice gases. For completeness, also some recent progress related to the above topics with trapped cold gases will be discussed.Comment: Review article. v2: published version, 135 pages, 34 figure

A Natural Supersymmetric Model with MeV Dark Matter

It has previously been proposed that annihilating dark matter particles with MeV-scale masses could be responsible for the flux of 511 keV photons observed from the region of the Galactic Bulge. The conventional wisdom, however, is that it is very challenging to construct a viable particle physics model containing MeV dark matter. In this letter, we challenge this conclusion by describing a simple and natural supersymmetric model in which the lightest supersymmetric particle naturally has a MeV-scale mass and the other phenomenological properties required to generate the 511 keV emission. In particular, the small ($\sim$ $10^{-5}$) effective couplings between dark matter and the Standard Model fermions required in this scenario naturally lead to radiative corrections that generate MeV-scale masses for both the dark matter candidate and the mediator particle.Comment: 4 pages, 1 figure. v2: Small modification to discussion of spectru

The Initial-Final Mass Relation among White Dwarfs in Wide Binaries

We present the initial-final mass relation derived from 10 white dwarfs in wide binaries that consist of a main sequence star and a white dwarf. The temperature and gravity of each white dwarf was measured by fitting theoretical model atmospheres to the observed spectrum using a $\chi^{2}$ fitting algorithm. The cooling time and mass was obtained using theoretical cooling tracks. The total age of each binary was estimated from the chromospheric activity of its main sequence component to an uncertainty of about 0.17 dex in log \textit{t} The difference between the total age and white dwarf cooling time is taken as the main sequence lifetime of each white dwarf. The initial mass of each white dwarf was then determined using stellar evolution tracks with a corresponding metallicity derived from spectra of their main sequence companions, thus yielding the initial-final mass relation. Most of the initial masses of the white dwarf components are between 1 - 2 M$_{\odot}$. Our results suggest a correlation between the metallicity of a white dwarf's progenitor and the amount of post-main-sequence mass loss it experiences - at least among progenitors with masses in the range of 1 - 2 M$_{\odot}$. A comparison of our observations to theoretical models suggests that low mass stars preferentially lose mass on the red giant branch.Comment: 28 pages, 8 figures, accepted for publication in Ap

Physics of Neutron Star Crusts

The physics of neutron star crusts is vast, involving many different research fields, from nuclear and condensed matter physics to general relativity. This review summarizes the progress, which has been achieved over the last few years, in modeling neutron star crusts, both at the microscopic and macroscopic levels. The confrontation of these theoretical models with observations is also briefly discussed.Comment: 182 pages, published version available at <http://www.livingreviews.org/lrr-2008-10