Robert M. Schofield | |
---|---|
Born | 1960 |
Other names | Robert M. S. Schofield |
Alma mater | B.A. Psychology, 1982 and B.A. Physics, 1983 Brigham Young University Ph.D., Biophysics, 1990 University of Oregon |
Awards | 2014 Fellow, American Physical Society 2017 Outstanding Accomplishment Non-Tenure-Track Faculty Research |
Scientific career | |
Fields | Physics Biophysics |
Thesis | X-ray microanalytic concentration measurements in unsectioned specimens: A technique and its application to zinc, manganese, and iron enriched mechanical structures of organisms from three phyla (1990) |
Doctoral advisor | Harlan w. Lefevre |
Robert M. Schofield (born 1960) is an American physicist and a research associate professor at the University of Oregon (UO). He was elected a Fellow of the American Physical Society in 2014.
Born in 1960, [1] Schofield holds bachelor's degrees in experimental psychology (1982) and in physics (1983) from Brigham Young University. He earned a Ph.D. in 1990 at the University of Oregon, with the dissertation, X-ray microanalytic concentration measurements in unsectioned specimens: A technique and its application to zinc, manganese, and iron enriched mechanical structures of organisms from three phyla, advised by Harlan W. Lefevre. [2]
Schofield held postdoctoral positions in the university's Institute of Molecular Biology and at Lund University. He then joined the UO as a research faculty member, [3] and was promoted in 2020 to research associate professor. [4]
Schofield's research interests include gravitational waves and structural biophysics. [5] He has been described as "an inter-disciplinarian, merging principles from physics, biology and materials science in pursuit of his passions". [6]
Schofield also found an unusual noise source that was recurring on hot summer afternoons: ravens were pecking the ice on pipes from a nitrogen cryopump maintaining the vacuum inside LIGO's concrete arms. Schofield said, "They peck for a while and make themselves a snow cone." [7] The remedy was to insulate the pipes to avoid attracting the ravens, and also to fix an instrument that jiggled when the ravens pecked. [7]
Schofield's work to enhance the sensitivity of the Laser Interferometer Gravitational-wave Observatory (LIGO) has allowed physicists to detect gravitational waves produced by colliding black holes. [3] LIGO's biggest challenge is detector noise, from seismic waves, thermal motion, and photon shot noise, disturbances that could mask signals from gravitational waves. [8] LIGO can detect "a truck rumbling past, the humming of a refrigerator in a nearby building, or the distant flutter of a plane’s propellers". [7]
Laura Hamers wrote, "Gravitational waves are so faint by the time they reach Earth that they can be drowned out by closer-to-home disturbances most of us wouldn't even notice. For example, the early LIGO detectors were so sensitive that water going over a dam 30 kilometers away could throw off the data, said Schofield, who co-leads the environmental monitoring at the Hanford detector. He and his colleagues have placed a bevy of sensors around the detectors, which keep track of external disruptions like rumbling traffic or crackling lightning." [9]
Elected a Fellow of the American Physical Society, Schofield was cited for "leadership in identifying and mitigating environmental factors which impact the sensitivity of terrestrial gravitational wave detectors and elimination [of] spurious noise sources in LIGO." [10]
BBC News said of Schofield's findings, "Central American leaf-cutter ants 'retire' from their cutting role when they grow old, switching to carrying when their jaws blunt with age... Dr Schofield and his team used electron microscopy to compare the pristine teeth of laboratory-reared pupae with the worn teeth of the wild forager ants." [11]
Schofield has found similarities between his research methods in biology and physics. For example, micromanipulators used in physics to guide a laser beam can be reconfigured to move an ant mandible through a leaf, allowing measurement of force. In addition, calculations Schofield uses in biology are similar to calculations in his work at LIGO. [12]
In January 2016, Schofield and five undergraduate researchers published a paper in Royal Society Open Science, making video clips of ants' leaf processing behaviors. [13] They "documented never-before-seen looks at the ants' prehensile skills — they're good at grabbing — and the layers of behaviors associated with gathering leaves, delivering them to the nests and processing them to grow the fungus that colony members eat". [14]
Schofield and 15 students from University of Oregon and Lane Community College conducted studies in 2021 that led to the discovery of the heavy element materials zinc and manganese in "ant mandibles, spider fangs and scorpion sting tips" that harden and sharpen their cutting tools. [15]
Schofield served as a mentor for McNair Scholars at UO between 2015 and 2017, supervising student participation in biology and biochemistry projects. [16]
In theories of quantum gravity, the graviton is the hypothetical quantum of gravity, an elementary particle that mediates the force of gravitational interaction. There is no complete quantum field theory of gravitons due to an outstanding mathematical problem with renormalization in general relativity. In string theory, believed by some to be a consistent theory of quantum gravity, the graviton is a massless state of a fundamental string.
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.
Einstein@Home is a volunteer computing project that searches for signals from spinning neutron stars in data from gravitational-wave detectors, from large radio telescopes, and from a gamma-ray telescope. Neutron stars are detected by their pulsed radio and gamma-ray emission as radio and/or gamma-ray pulsars. They also might be observable as continuous gravitational wave sources if they are rapidly spinning and non-axisymmetrically deformed. The project was officially launched on 19 February 2005 as part of the American Physical Society's contribution to the World Year of Physics 2005 event.
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).
The gravitational wave background is a random background of gravitational waves permeating the Universe, which is detectable by gravitational-wave experiments, like pulsar timing arrays. The signal may be intrinsically random, like from stochastic processes in the early Universe, or may be produced by an incoherent superposition of a large number of weak independent unresolved gravitational-wave sources, like supermassive black-hole binaries. Detecting the gravitational wave background can provide information that is inaccessible by any other means about astrophysical source population, like hypothetical ancient supermassive black-hole binaries, and early Universe processes, like hypothetical primordial inflation and cosmic strings.
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Gravitational waves are transient displacements in a gravitational field – generated by the relative motion 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.
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The first direct observation of gravitational waves was made on 14 September 2015 and was announced by the LIGO and Virgo collaborations on 11 February 2016. Previously, gravitational waves had been inferred only indirectly, via their effect on the timing of pulsars in binary star systems. The waveform, detected by both LIGO observatories, matched the predictions of general relativity for a gravitational wave emanating from the inward spiral and merger of two black holes and the subsequent ringdown of a single, 62 M☉ black hole remnant. The signal was named GW150914. It was also the first observation of a binary black hole merger, demonstrating both the existence of binary stellar-mass black hole systems and the fact that such mergers could occur within the current age of the universe.
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David M. Strom is an experimental high energy particle physicist on the faculty of the University of Oregon.
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Lisa Barsotti is a research scientist at the Massachusetts Institute of Technology Kavli Institute.
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