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Coherence and Interference of Light
Published in Lazo M. Manojlović, Fiber-Optic-Based Sensing Systems, 2022
Being highly sensitive, interferometers can be used to measure different physical quantities with an ultimate precision. Typically, interferometers perform vibration amplitude measurement, flow velocity as well as flow velocity distribution measurement, rotation angles as well rotation velocity measurement. Moreover, today’s state-of-the-art measurement such as gravitational wave detectors are interferometer based.
Waves
Published in Daniel H. Nichols, Physics for Technology, 2019
Gravitational waves are ripples in space-time that travel at the speed of light caused by some violent and energetic event such as the merger of two black holes. Albert Einstein predicted such waves in 1916, in his theory of gravity, General Relativity. In 2015, approximately 100 years after Einstein’s prediction, these waves were first detected. The source of this detection turned out to be two black holes spiraling into one another. General Relativity predicts that when a mass is accelerated it will produce waves on the space surrounding it, think of ripples on a pond when a rock is tossed in. These waves are extremely weak and require extremely large accelerated masses, and a very sensitive instrument to measure them. This first detection of gravitational waves took place on twin Laser Interferometer Gravitational-wave Observatory (LIGO) detectors, located in Livingston, Louisiana and Hanford, Washington, USA (Figure 15.43). The signals measured in these detectors agree with the prediction of the merger of two black holes about 29 and 36 times the mass of the sun 1.3 billion years ago; it took 1.3 billion years traveling at the speed of light to reach us.
Physics, science and technology in the future
Published in Kléber Ghimire, Future Courses of Human Societies, 2018
The effort to unify gravity with the other three fundamental forces is called quantum gravity. It postulates the existence of a virtual particle called the graviton, which would be the mediating element in gravity interactions. The recent discovery of the gravitational waves predicted by Einstein’s general theory of relativity opened up a new front to further understanding the universe. The discovery also represents the first experimental evidence for quantum gravity, a hypothetical union of quantum mechanics and general relativity. It is possible that an understanding of quantum gravity will not merely consolidate the theories, but will rather introduce a fundamentally new understanding of space and time. Will there be some breakthrough in these areas allowing the emergence of whole new fields that were completely untapped previously, as some scientists have suggested (Wilczek, 2016, pp. 33–39)?
Optimal Data Placement for Scientific Workflows in Cloud
Published in Journal of Computer Information Systems, 2023
In order to compare the effects of the proposed algorithm on the workflow scheduling problem to those of existing techniques, extensive tests are run on real-world workflow applications using the simulation parameters in Table 2. Some work has been done to characterize the performance behaviors of scientific operations. The following workflow structures are used in this paper: Ligo, Montage, and Epigenomics. The Ligo (Laser Interferometer Gravitational-Wave Observatory) application detects gravitational waves. Montage is a popular astronomy application benchmark for Grid and parallel computing. Epigenomics is a data processing pipeline that includes several genome sequencing processes. Montage, for example, is an I/O-intensive activity, while Ligo is memory-intensive and Epigenomics is CPU-intensive. Consequently, the efficacy of our suggested method on diverse workloads involving the three processes is examined.
Linearity performance analysis of the differential wavefront sensing for the Taiji programme
Published in Journal of Modern Optics, 2020
Ruihong Gao, Heshan Liu, Ziren Luo, Gang Jin
In 2016, the American ground-based laser interferometer gravitational wave observatory (LIGO) announced the first direct detection of gravitational waves. The exciting news promoted China to propose its space-based gravitational wave detection programme, the Taiji programme, for reaching a wider range of gravitational radiation sources [1–4]. Compared with the ground-based programmes, the Taiji programme has to construct the inter-satellite laser link constellation with the help of a laser acquisition system. The system uses star trackers and CCD detectors to suppress the laser pointing error from to [5–8]. However, the satellite jitter caused by the solar wind, solar radiation, cosmic rays and other space environment hinders the acquirement of the scientific data. The drag free system suppresses such noise extensively, but the residual jitter is still coupled to the propagating laser and dominates the ranging noise. In order to reduce the detection error caused by the pointing jitter while taking into account redundancy, the Taiji programme plans to adopt the precision pointing system to achieve the pointing stability of in the frequency band within . The precision pointing system is based on the Differential Wavefront Sensing (DWS) technique [9].
Light, the universe and everything – 12 Herculean tasks for quantum cowboys and black diamond skiers
Published in Journal of Modern Optics, 2018
Girish Agarwal, Roland E. Allen, Iva Bezděková, Robert W. Boyd, Goong Chen, Ronald Hanson, Dean L. Hawthorne, Philip Hemmer, Moochan B. Kim, Olga Kocharovskaya, David M. Lee, Sebastian K. Lidström, Suzy Lidström, Harald Losert, Helmut Maier, John W. Neuberger, Miles J. Padgett, Mark Raizen, Surjeet Rajendran, Ernst Rasel, Wolfgang P. Schleich, Marlan O. Scully, Gavriil Shchedrin, Gennady Shvets, Alexei V. Sokolov, Anatoly Svidzinsky, Ronald L. Walsworth, Rainer Weiss, Frank Wilczek, Alan E. Willner, Eli Yablonovitch, Nikolay Zheludev
The strain caused by gravitational waves can be observed by measuring oscillations in the distance between two spatially separated objects. This requires inertial proof masses whose positions are decoupled from the environment and a clock that is accurate enough to monitor these oscillations. In laser interferometers such as LIGO, the proof masses are suspended from well-engineered vibration isolation systems, while the laser provides the clock necessary for the measurement. However, current lasers do not have the accuracy to measure the tiny strain caused by gravitational waves – in order to mitigate this problem, laser interferometers operate using two non-parallel baselines. In this scheme, the noise from the laser is common to both baselines while the gravitational wave strain is different. A differential measurement results in significant cancellation of noise from the laser while preserving the gravitational wave strain.