Schema della sezione

  • Introduzione

    Minimizza tutto Espandi tutto

    Resources

    introduction to cosmology:
    - lecture notes by Baumann http://cosmology.amsterdam/education/cosmology/
    - book by Baumann (Baumann, D. (2022) Cosmology. Cambridge: Cambridge University Press.)
    - book by Kolb & Turner (    The Early Universe, Front. Phys. 69 (1990), 1-547 doi:10.1201/9780429492860)

    cosmological constant:
    - introductory review by Carroll https://arxiv.org/abs/astro-ph/0004075
    - Casimir effect is treated in the QFT notes by Tong https://www.damtp.cam.ac.uk/user/tong/qft.html
    - anthropic argument: see Carroll

    dark matter
    - the most comprehensive review is this book: https://www.cambridge.org/core/books/particle-dark-matter/B03C934EAB188884EFC6B02432632496. Many (most?) chapters can be found on arXiv as preprints
    - historical perspective https://arxiv.org/abs/1605.04909
    - some nice set of lectures: https://arxiv.org/abs/1603.03797 by Mariangela Lisanti, https://arxiv.org/abs/1301.0952 by Stefano Profumo
    - relic abundance: Gondolo&Gelmini (https://inspirehep.net/literature/304505)

    axions and axion DM
    - lectures by Anson Hook (https://arxiv.org/abs/1812.02669)
    - long/complete review by Marsh (https://arxiv.org/abs/1510.07633)
    - Kolb & Turner

    classical fields in cosmology
    - quantum to classical transition: Anthony Duncan, The Conceptual Framework of Quantum Field Theory, Oxford University Press
    - Robert Brandenberger, Quantum Field Theory Methods and Inflationary Universe Models, https://inspirehep.net/literature/14969

    gravitational waves
    - a good introduction is

  • Lecture notes

  • Esame

    Articoli proposti per il seminario di esame (aggiungerò altri riferimenti man mano)

    • Freeze-out della materia oscura studiato in dettaglio
      Gondolo & Gelmini, Nucl.Phys.B 360 (1991) 145-179

    • eccezioni al calcolo del freeze-out visto a lezione
      Griest & Seckel, Phys.Rev.D 43 (1991) 3191-3203

    • Freeze-in DM prodotta tramite scattering
      Teresi & Heeck, https://arxiv.org/abs/1706.09909

    • Accoppiamento dell'assione QCD ai mesoni con la Lagrangiana chirale
      Grilli di Cortona et al., https://arxiv.org/abs/1511.02867
      Hook, https://arxiv.org/abs/1812.02669

    • Discutere in dettaglio un tipo di ricerca di assioni

    • Axion superradiance

    • Bound su particelle leggere dato dal numero effettivo di neutrini \Delta N_{eff}

    • Cosmic strings (Hindmarsh and Kibble https://inspirehep.net/literature/380099)

    • Buchi neri primordiali (PBH): meccanismo di formazione, cenni ai limiti sulla frazione f_PBH (https://arxiv.org/pdf/1801.05235)

    • Tunnelling in QFT

  • Lezione 1 - 04/03

    Introduction. What is cosmology. Why are cosmology and high energy physics related. FRLW metric. Hubble constant. Redshift.

  • Lezione 2 - 05/03

    Energy density and pressure, energy-momentum tensor. Continuity equation. Equation of state. Friedmann equations and their solution. EOS for non-relativistic matter, radiation, cosmological constant and kinetic energy. Cosmic history. Critical density.

  • Lezione 3 - 11/03

    Present energy budget of the Universe. Brief summary of the cosmological history. Flatness of the Universe. Age of the Universe. Stellar age problem. Cosmological constant in the Einstein equation and as a new type of fluid. Cosmological constant "problem". Potential energy of a scalar field. Fine-tuning and phase transitions.

  • Lezione 4 - 12/03

    Vacuum energy and Casimir effect. Measuring the accelerated expansion with SN Ia. Anthropic principle.

  • Lezione 5 - 25/03

    An aside on the Planck mass. The Universe at thermal equibrium. Energy density. Effective number of relativistic degrees of freedom. Entropy density. Conservation of entropy.

  • Lezione 6 - 26/03

    Evidences of the existence of DM

  • Lezione 7 - 08/04

    General properties of DM. Distribution at the galactic scale. Lower mass bounds: ultra-light bosons, Tremaine-Gunn bound. Electric charge. Self-interactions. DM lifetime. DM is cold: free-streaming length and matter power-spectrum.

  • Lezione 8 - 09/04

    Thermal production of DM and freeze-out. Annihilation rate. Departure from thermal equilibrium. Hot freeze-out. Coswik-McClelland bound on hot DM mass. Neutrino decoupling. Cold freeze-out. WIMP miracle.

  • Lezione 9 - 12/04

    Chemical vs. kinetic decoupling. Boltzmann equation. Liouville and collision operators. Boltzmann eq for WIMP pair annihilation. Role of \Gamma/H.

  • Lezione 10 - 15/04

    Thermal average of \sigma v. Moller velocity. Choice of reference frame. Low velocity expansion. Mass window of cold relics produced via freeze-out. Exceptions: resonances, thresholds, coannihilations, Sommerfeld enhancement, bound states.

  • Lezione 11 - 16/04

    DM freeze-in

  • Lezione 12 - 22/04

    Entropy injection from the decay of a heavy, decoupled species. Effect on DM abundance. Direct DM searches.

  • Lezione 13 - 23/04

    Indirect Detection (with focus on photons). DM from neutrinos in the Sun. DM at colliders.

  • Lezione 14 - 29/04

    DM annihilation cross section: bounds from CMB and BBN. Introduction to axions. Strong CP problem.

  • Lezione 15 - 30/04

    Electric dipole moment and CP violation. QCD axion. Theory overview, potential, mass, temperature dependence, couplings, stability. Mention the axion quality problem. Axion-like particles.

  • Lezione 16 - 06/05

    Axions as DM: thermal production, decay of cosmic strings, misalignment.

  • Lezione 17 - 07/05

    Axion misalignment. Solution of the equation of motion. Relic abundance. Initial angle: PQ breaking during or after inflation.

  • Lezione 18 - 16/05

    Axion searches and axion DM searches.

  • Lezione 19 - 20/05

    What is a classical field? Commutation relations, uncertainty relations. Coherent states.

  • Lezione 20 - 21/05

    Campi classici con valore di aspettazione arbitrario. Rottura spontanea di simmetria. Cenni al potenziale efficace

  • Lezione 21 - 27/05

    General introduction to Gravitational Waves. GWs propagate freely from the very early universe. Linearized gravity around Minkowski. Lorentz gauge condition, transverse-traceless gauge. GWs have 2 polarizations.

  • Lezione 22 - 28/05

    Linear expansion around Minkowski, with matter.  Definition of GWs as radiative and gauge-invariant tensor perturbations. GWs in a curved background. Scale separation for distinguishing GWs from the background. Energy-momentum tensor and GW energy. GWs in FLRW. Solution of the homogeneous equation in the sub-horizon and super-horizon limits.

  • Lezione 23 - 03/06

    GWs of cosmological origins form a stochastic background. Power spectrum. Energy density. Propagation of GWs through cosmic history. Sensitivity range of GW experiments. Solution of the inhomogeneous equation and GW spectrum today.

  • Lezione 24 - 04/06

    Gravitational waves from phase transitions. Constraint on N_eff. GW searches at interferometers. PTA signal.