Detection Physics and Technology of Gravitational Waves --- GR and Principle of GW detection --- Kazuaki Kuroda ICRR, University of Tokyo 7 th August, 2013 APCTP Pohang, Korea

Introduction of the Lecturer Dr. Kazuaki Kuroda Born in Miyazaki, Kyushu in 1951 Bachelor of Engineering, UTokyo in 1974 Ph. D degree, UTokyo in 1985 Theme of Ph.D is “Test of Newtonian Inverse Square Law of gravitation” Precision metrology, Gravity experiment, Gravitational wave project

Content of Lecture Introduction to Research on Gravitation Chapter 1: Fundamental physics for GW Chapter 2: Science of GW detection Chapter 3: Current effort to detect GW

Introduction to Research on Gravitation (1) We have a question “What is the Universe? Where did we come from? …..” To solve this main question, we observed the Universe and established many theories by which we can reach the goal step by step The most powerful theory to tackle with the Universe is Einstein’s theory of general relativity However, we have to keep in mind that any theory cannot be all mighty and needs to be tested by observations or experiments

Introduction to Research on Gravitation (2) We believe BigBang & Inflation cosmology Particle physics and astronomy are pursuing the same subject Dark matter and dark energy are the most active subject for both research fields Gravitational wave is possibly powerful tool in this field

Gravity waves are produced dynamic motion of massive terrestial objects. Here consider the radiation by simple rotating equal masses Radiation formula of EM: Luminosity = (2/3c 3 ) e 2 a 2 Radiation from Mass dipole moment = 0 Radiation of mass quadrupole moment is the lowest term of gravity wave Gravity wave luminosity = (G/5c 5 )( I ) 2 I = I jk I jk, I jk = Σm A (x Aj x Ak -1/3δ jk r A 2 ) I jk : the reduced quadrupole moment Introduction to Research on Gravitation (3)

Introduction to Research on Gravitation (4) PSR B PSR B PSR J PSR J PSR J Existing neutron star binaries in our Galaxy Sources of gravitational waves are typically 1. Coalescence of neutron star binaries 2. Coalescence of black hole binaries 3. Core collapse of massive stars msec chirp signal coalescence quasi-mode oscillation -300Hz-1kHz

Introduction to Research on Gravitation (5) J. Weber started to make practical detector in late of 1960s Gravity plane wave h 11 h h 21 h h ij = Disk type: Resonant frequency could be changed by making slits Bar type: Resonant frequency was determined by the length of the bar Tidal force of gravity wave causes elastic vibration of eigenmode, which can be detected by sensitive transducer. Thermal noise of vibration is reduced by lowering the temperature. GR is being tested as in Angela’s talk

Introduction to Research on Gravitation (6) I would like to let you learn the fundamental theory of general relativity and its experimental basis at first, which is today’s subject Elemental lecture on general relativity presented here is based on the introduction of “Gravitation” by Charles Misner, Kip Thorne, Wheeler published in 1972 If you are not lazy, I recommend you to refer the book Although I tried to accord the convention of the book about presentation of characters, there may be many different appearances from the book