The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a large-scale physics experiment and observatory designed to detect cosmic gravitational waves and to develop gravitational-wave observations as an astronomical tool. Two large observatories were built in the United States with the aim of detecting gravitational waves by laser interferometry. These observatories use mirrors spaced four kilometers apart to measure changes in length—over an effective span of 1120 km—of less than one ten-thousandth the charge diameter of a proton.
The Max Planck Institute for Gravitational Physics is a Max Planck Institute whose research is aimed at investigating Einstein's theory of relativity and beyond: Mathematics, quantum gravity, astrophysical relativity, and gravitational-wave astronomy. The institute was founded in 1995 and is located in the Potsdam Science Park in Golm, Potsdam and in Hannover where it closely collaborates with the Leibniz University Hannover. Both the Potsdam and the Hannover parts of the institute are organized in three research departments and host a number of independent research groups.
GEO600 is a gravitational wave detector located near Sarstedt, a town 20 kilometres (12 mi) to the south of Hanover, Germany. It is designed and operated by scientists from the Max Planck Institute for Gravitational Physics, Max Planck Institute of Quantum Optics and the Leibniz Universität Hannover, along with University of Glasgow, University of Birmingham and Cardiff University in the United Kingdom, and is funded by the Max Planck Society and the Science and Technology Facilities Council (STFC).
Quantum metrology is the study of making high-resolution and highly sensitive measurements of physical parameters using quantum theory to describe the physical systems, particularly exploiting quantum entanglement and quantum squeezing. This field promises to develop measurement techniques that give better precision than the same measurement performed in a classical framework. Together with quantum hypothesis testing, it represents an important theoretical model at the basis of quantum sensing.
The Virgo interferometer is a large Michelson interferometer designed to detect the gravitational waves predicted by general relativity. It is in Santo Stefano a Macerata, near the city of Pisa, Italy. The instrument's two arms are three kilometres long and contain its mirrors and instrumentation inside an ultra-high vacuum.
Gravitational waves are transient displacements in a gravitational field—generated by the motion or acceleration of gravitating masses—that radiate outward from their source at the speed of light. They were first proposed by Oliver Heaviside in 1893 and then later by Henri Poincaré in 1905 as the gravitational equivalent of electromagnetic waves. In 1916, Albert Einstein demonstrated that gravitational waves result from his general theory of relativity as ripples in spacetime.
A gravitational-wave detector is any device designed to measure tiny distortions of spacetime called gravitational waves. Since the 1960s, various kinds of gravitational-wave detectors have been built and constantly improved. The present-day generation of laser interferometers has reached the necessary sensitivity to detect gravitational waves from astronomical sources, thus forming the primary tool of gravitational-wave astronomy.
Gravitational-wave astronomy is a subfield of astronomy concerned with the detection and study of gravitational waves emitted by astrophysical sources.
The Australian International Gravitational Observatory (AIGO) is a research facility located near Gingin, north of Perth in Western Australia. It is part of a worldwide effort to directly detect gravitational waves. Note that these are a major prediction of the general theory of relativity and are not to be confused with gravity waves, a phenomenon studied in fluid mechanics.
David Howard Reitze is an American laser physicist who is professor of physics at the University of Florida and served as the scientific spokesman of the Laser Interferometer Gravitational-Wave Observatory (LIGO) experiment in 2007-2011. In August 2011, he took a leave of absence from the University of Florida to be the Executive Director of LIGO, stationed at the California Institute of Technology, Pasadena, California. He obtained his BA in 1983 from Northwestern University, his PhD in physics from the University of Texas at Austin in 1990, and had positions at Bell Communications Research and Lawrence Livermore National Laboratory, before taking his faculty position at the University of Florida. He is a Fellow of the American Physical Society, the Optical Society, and the American Association for the Advancement of Science.
Barry Clark Barish is an American experimental physicist and Nobel Laureate. He is a Linde Professor of Physics, emeritus at California Institute of Technology and a leading expert on gravitational waves.
Nergis Mavalvala is a Pakistani-American astrophysicist. She is the Curtis and Kathleen Marble Professor of Astrophysics at the Massachusetts Institute of Technology (MIT), where she is also the dean of the university's school of science. She was previously the Associate Head of the university's Department of Physics. Mavalvala is best known for her work on the detection of gravitational waves in the Laser Interferometer Gravitational-Wave Observatory (LIGO) project, and for the exploration and experimental demonstration of macroscopic quantum effects such as squeezing in optomechanics. She was awarded a MacArthur Fellowship in 2010.
David Ernest McClelland is an Australian physicist, with his research focused on the development of the manipulation and control of optical quantum states, and its implementation into gravitational wave observatories. He is a Fellow of the Australian Academy of Science, the American Physical Society and the Optical Society of America. Since 2001, he has been a professor at the Australian National University (ANU) in the Research School of Physics and Engineering, in Canberra (Australia). He is Director of the ANU's Centre for Gravitational Astrophysics and Deputy Director of OzGrav - the Australian Research Council Centre of Excellence in Gravitational Wave Discovery.
In quantum physics, light is in a squeezed state if its electric field strength Ԑ for some phases has a quantum uncertainty smaller than that of a coherent state. The term squeezing thus refers to a reduced quantum uncertainty. To obey Heisenberg's uncertainty relation, a squeezed state must also have phases at which the electric field uncertainty is anti-squeezed, i.e. larger than that of a coherent state. Since 2019, the gravitational-wave observatories LIGO and Virgo employ squeezed laser light, which has significantly increased the rate of observed gravitational-wave events.
Bonny Laura Schumaker is an American physicist and pilot who worked on the LISA Pathfinder. In 2010 she founded the nonprofit "On Wings of Care", a charity which protects animals and environments.
Michel Davier is a French physicist.
Jean-Paul Richard was a Canadian physicist, academic and researcher. He was a Professor of Physics at the University of Maryland.
Rana X. Adhikari is an American experimental physicist. He is a professor of physics at the California Institute of Technology (Caltech) and an associate faculty member of the International Centre for Theoretical Sciences of Tata Institute of Fundamental Research (ICTS-TIFR).
Lisa Barsotti is a research scientist at the Massachusetts Institute of Technology Kavli Institute.
Ground-based interferometric gravitational-wave search refers to the use of extremely large interferometers built on the ground to passively detect gravitational wave events from throughout the cosmos. Most recorded gravitational wave observations have been made using this technique; the first detection, revealing the merger of two black holes, was made in 2015 by the LIGO sites.
