DescriptionOn October 3 2017, the Nobel Prize for Physics was awarded to Weiss, Thorne and Barish for the direct detection of gravitational waves, which are ripples in the fabric of spacetime created by mass in movement. The first direct gravitational wave detection happened in 2015 at LIGO in the United States and since then, other interferometers, notably VIRGO located in Italy, participate to the worldwide effort of detecting more events. These occur from the merger of two supermassive objects, either two black holes, two neutron stars or a black hole and a neutron star.The history of gravitational waves is fascinating and is a prime example of physics endeavour at its best. From Einstein's prediction of their existence within General Relativity, the experimental discovery of the pulsar PSR B1913+16 in 1974 by Hulse and Taylor (Nobel Laureates 1993), the creative calculations - both by hand and later on using sophisticated numerical methods - to provide a wave profile precise enough to be detected, to state of the art technology to detect them. Just like electromagnetic waves in the invisible band have revealed a host of cosmic phenomena during the last century, the direct detection of gravitational waves opens up a new window on the Universe which was previously hidden to us because they are `opaque' to light and electromagnetic waves in general. The project will start with a basic introduction to Einstein's equations of General Relativity, building up on the Special Relativity and Electromagnetism course at level 2, and basic concepts relating to gravitational waves, comparing and contrasting them with electromagnetic waves and sound waves. For instance, while electromagnetic radiation needs oscillating electric dipoles, gravitational radiation needs oscillating quadrupole moments. We will analyse Einstein's quadrupole formula and explore whether the linear approximation in which he calculated it is sufficient to prove the existence of physical gravitational waves. The emphasis of the project will be tailored to each student. For instance, one could analyse the main sources of gravitational waves in more detail, or concentrate on calculations of mergers of supermassive objects, or indeed any piece of mathematics related to gravitational waves.
PrerequisitesSpecial Relativity and Electromagnetism II (MATH2657) is recommended.Resources- You can find the theory of gravitational waves in several classical textbooks, but the following Lecture Notes on General Relativity by Sean Carroll are a must.- The Les Houches lecture notes by Alessandra Buonanno may also be helpful. - The web is packed with information relevant to the project. Type `Gravitational Waves' in Google to get a feel for the subject. More specific resources will be shared with the students who choose the project. - For those interested in history of science, the Physics Today article Einstein Versus the Physical Review is worth a look. |
email: Anne Taormina