Università degli Studi di Perugia

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Unit EXPERIMENTAL GRAVITATION

Course
Physics
Study-unit Code
55A00007
Curriculum
Astrofisica e astroparticelle
Teacher
Helios Vocca
Teachers
  • Helios Vocca - Didattica Ufficiale
Hours
  • 42 ore - Didattica Ufficiale - Helios Vocca
CFU
6
Course Regulation
Coorte 2017
Offered
2018/19
Learning activities
Affine/integrativa
Area
Attività formative affini o integrative
Sector
FIS/03
Type of study-unit
Opzionale (Optional)
Type of learning activities
Attività formativa monodisciplinare
Language of instruction
Italian
Contents
From general relativity to gravitational waves. The nature of gravitational waves. Sources of gravitational waves.
Gravitational waves and their interaction with matter. Elements of noise measurement theory. Gravitational wave detectors and measurement techniques.
Reference texts
P. Saulson, Fundamentals of Interferometric Detection of Gravitational waves, World Scientific 1994

C.M. Will, Theory and experiment in gravitational physics, Cambridge University Press

M. Maggiore, Gravitational Waves, Volume 1: Theory and experiments
Educational objectives
Provide students with the basics of the principles of the theory of gravitation and its experimental consequences.
Prerequisites
Knowledge of the fundamentals of the theory of General Relativity
Teaching methods
Lectures will be made by using slides and movies. Some lessons could be dedicated to revision and depth of issues also proposed by the students and that could involve students themselves.
Learning verification modality
The exam consists in an oral examination. The examinations are designed at evaluating the student's knowledge and understanding of the topics presented during the course.
Extended program
From general relativity to gravitational waves:
the Newtonian theory of gravitation. Gravity compared to the other forces of nature. Inertial mass and gravitational mass. The principle of equivalence and the Einstein equation. The transverse-traceless gauge and the gravitational wave equation.

The nature of gravitational waves:
The polarization of gravitational waves. The Michelson-Morley experiment and a schematic detector of gravitational waves. Description of gravitational waves in terms of force.

Gravitational waves and their effect on matter:
Intensity and brightness of the source. Generation of gravitational waves and notes on the astrophysical sources of gravitational waves: coalescence of binary systems, rotating neutron stars, stellar collapse. Astrophysical background and cosmological background of gravitational waves. Reduction of the orbital period due to GW emission.

Review of noise theory in measuring instruments:
Stochastic processes. Mean, variance, correlation, autocorrelation. Harmonic process. Poisson process. Transformations of stochastic processes. Systems without memory. Linear transformations. Power spectrum. Fluctuation-Dissipation Theorem. Thermal noise in electrical circuits. Thermal noise in a pendulum. Reduction of seismic noise and thermal noise; suspension systems. The signal-to-noise ratio and the problem of linear data filtering.

Gravitational wave detectors and measurement techniques:
Modulation and revelation in phase. Wide band optical detectors. Michelson interferometer and Fabry-Perot cavity. Recicling of light. Opto-mechanical systems with feedback: Pound-Drever-Hall technique. Shot noise and radiation pressure reduction. Mechanical narrow band detectors. Low noise transduction and amplification systems. The quantum limit of gravitational detectors and the strategies to overcome this limit. Gravitational wave detectors in space.

Gravitational signal detection:
The problem of signal detection. Probability distribution of the time series. Coincidence detection. Optimum orientation. Local coincidences. Search for periodic sources and astrophysical background.

Gravitational astronomy:
Position of a gravitational wave source. Network figure of merit and temporal coincidence with non-gravitational signals. Interpretation of gravitational waveforms: core collapse, binary coalescenses, gravitational candles, black holes.
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