### Courses within PhD programme in Physics

#### Computational Methods for Tomographic Image Reconstruction in Medical Imaging

- Area: Applied Physics
- Teacher: N. Belcari, D. Panetta
- Programmed Period: mid February – mid May
- Structure: 40 hours total
- Language: English

The course provides an introduction to the problem of image reconstruction from projections, with particular emphasis on Computed Tomography (CT) and Positron Emission Tomography (PET). Even though this topic is often seen as a branch of pure mathematics, referred to as Tomographic Reconstruction, it is indeed a strongly multidisciplinary domain involving, physics, engineering, computer science and, of course, any discipline relevant for the final application (not just medical) for which the above-mentioned imaging modalities are used.

After an introduction to CT and PET imaging principles and related technologies the student will be guided through the mathematical formalization of the image reconstruction process and several computational techniques are introduced and discussed. About 50% of the hours will be dedicated to practical exercises on image reconstruction. A background of scientific programming in Python/Numpy is necessary to get a fruitful understanding of the sample code, listings and Jupyter notebooks provided during the course, even though this is not required for the comprehension of the theory itself.

Lectures will be held in class twice a week.

At the end of the course, students are expected to individually complete a project in which they provide a practical solution to an image reconstruction problem, starting from simulated and/or experimental projection data.

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#### The Hubble Constant and the Age of the Universe

- Area: Astronomy and Astrophysics
- Teachers: M. Cignoni, S. Degl’Innocenti, P. Prada Moroni
- Programmed Period: mid February – end of May
- Structure: 40 hours total
- Language: English

The cosmic distance ladder provides the most direct measurement of the Hubble constant H0, whose first rung is set by the absolute calibration of the Cepheids pulsating stars. In turn, Cepheids calibrate the next rung of the ladder, where supernovae type Ia trace the Hubble flow. H0 can also be determined by interpreting the Cosmic Microwave Background, which is the cooled remnant of the first light that could ever travel freely throughout the Universe. In this context, the “Hubble tension” refers to the discrepancy of about 6 km/s/Mpc between the result obtained with the distance ladder (late Universe) method and the CMB (early Universe) method. If the measurements performed in both methods are correct, this tension might imply some underlying new physics.

General program:

*1) Hubble’s law and the expanding Universe**2) The cosmic distance ladder.**3) Parallaxes in the Gaia era**4) Eclipsing binaries**5) Pulsating stars: Cepheids and RR-Lyrae**6) Tip of the red giant branch**7) Independent approaches: surface brightness fluctuation, water masers, time-delay gravitational lensing, Tully-Fisher relation**8) The last rung: Supernovae type Ia**9) Distances in cosmology**10) The Hubble relation**11) The Cosmic Microwave Background**12) How we estimate the age of the Universe**13) Stellar clocks*

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#### Non-perturbative Aspects of Quantum Field Theories

- Area: Theoretical Physics
- Teachers: V. Alba, S. Bolognesi, M. D’Elia, E. Vicari, A. Vichi
- Programmed period: November – January
- Structure: 4 modules of 20 hours each
- Language: English

The purpose of the course is to provide a thorough knowledge about the main approaches used in theoretical physics to study strongly coupled system, which cannot be investigated by standard perturbative tools. Within the standard model of particle physics, this happens for Quantum Chromodynamics (QCD) at the low energy hadronic scale. Analogous non-perturbative approaches are required in condensed matter and in the theory of critical phenomena, where one usually deals with strongly coupled systems. The course is divided in four parts, each of them corresponding to 3 CFU, which are related to each other by a common language and tools and by various common aspects, but are anyway self-consistent by themselves. The first part (S. Bolognesi) is dedicated to the investigation of the role of Topological Solitons in QFT; the second part (M. D’Elia) deals with the Lattice formulation of Quantum Gauge Theories; the third part (E. Vicari) is dedicated to Renormalization Group Theory and the Large N Expansion; the fourth part (A. Vichi) focusses on anomalies in QFT and Conformal Field Theories. The student can make a selection among these parts. The expected competences to be acquired by the student, to be verified in the final oral exam, consist both in specific knowledges about the various topics and in the ability to connect and interrelate different concepts.

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#### Quantum Liquids

- Area: Condensed Matter Physics
- Teacher: M.L. Chiofalo, J.Y. Malo
- Programmed Period: mid November – March
- Structure: 60 hours total (with the possibility to select 40 h)
- Language: English

At the end of the course, the student will have developed conceptual, procedural and factual knowledge in the physics of quantum liquids at equilibrium (40 hours) and of open driven-dissipative quantum systems (20 hours) and their engineering as quantum simulators in current quantum technology platforms. In particular:

- Advanced theoretical methods to predict and characterize the physics of quantum liquids at equilibrium, their relationship to quantum simulation methods, and their classification by functionality and problem types. Among the methods: linear response, quantum hydrodynamics, functional density and current, Green functions and non-perturbative methods, bosonization.
- Theoretical and simulational methods for out-of-equilibrium and driven-dissipative quantum systems: Markovian and non-Markovian systems, dissipative engineering, simulation through stochastic methods and tensor networks, measurement and feedback, and applications to quantum technologies, quantum chemistry and biology.
- Principles of operation of the main platforms of quantum technologies: atoms, dipolar and Rydberg atoms, ultracold ions, atoms in QED cavities; superconducting circuits; light fluids in optical cavities; low dimensional systems. Their use as quantum simulators for condensed matter, fundamental physics, quantum metrology, analogous gravity, and cosmology.

Students will select 40 out of the 60 hours according to their needs and interests.

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#### Scientific Writing for Physicists

- Area: cross-sectoral
- Teachers: Steve N. Shore
- Programmed period: Spring 2023
- Structure: 4-6 hours divided in two afternoons
- Language: English

**Requirements:** there will be required readings (distributed in advance and also during the session), assigned project; requirement of interactive participation.**Overview:** During the first part, the general issues of scientific writing will be covered. In all cases detailed examples will be provided and prepared for the second part when you will bring your work for analysis. There will be assigned work after the each day that will be due for the next session. Please allow time for the exercises, the material will be of little use without the individual work.

- Scientific journals: an overview editorial-referee structure of journals – the submission and review process at different journals and how it’s developed, overview
- Structure of a paper, details of construction: abstracts, introductions, discussions
- Citations and the literature
- Ethical issues: this is a particularly important part of the course
- Statistics, experimental details, how complete does the paper need to be?
- Graphs, figures: preparation issues (this is NOT as simple as it seems)
- The submission process – preparing the paper
- Responding to a referee report(s)
- Facilities, acknowledgments
- How to prepare a referee report
- Grant proposals, various examples
- Conference presentations: preparing your talk (additional material: conference proceedings: preparing the paper
- Internal refereeing (collaborations) (this will take some time, be prepared with examples of your own for the discussions)
- Posting papers online: when, how, why?

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#### Gravitational Waves Physics and Astrophysics

- Area: Astronomy and Astrophysics
- Teacher: W. Del Pozzo, A. Ricciardone, S. Shore
- Programmed Period: mid February – mid May
- Structure: 40 hours
- Language: English

The field of gravitational wave physics has grown rapidly after the LIGO/Virgo collaboration detected for the first time in 2015 gravitational waves emitted by the merger of a black hole binary system. Gravitational Waves are emitted both by the merging of astrophysical compact objects (Black Holes, Neutron Stars, Core Collapse SN, etc) and from early universe mechanisms, like inflation, phase transitions.

In this course, we will present the latest advances in the field and provide advanced tools to extract physical and astrophysical information from the detection of resolved and stochastic GW signals. We will review the state of the art data analysis techniques required for source identification for current ground-based, such as LIGO, Virgo and Einstein Telescope, and space-based interferometers, such as LISA.

The evaluation will be based on a seminar on one or more topics dealt with during the course, to be chosen in consultation with the instructors. The course will be taught in English and will be held also online (on the Teams platform).

Requirements: general relativity. A background in astrophysics is not assumed.

GENERAL PROGRAM:

1) Basics of GW physics;

2) Characterization of Stochastic Gravitational Wave Backgrounds;

3) Detector Response to a GW signal;

4) Early Universe Cosmology with Gravitational Waves;

5) Late Universe Cosmology with Gravitational Waves;

6) Test of GR with Gravitational Waves;

7) GW anisotropies and correlation with other cosmological observables;

##### More details

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