Hume Feldman
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Hume A. Feldman is a physicist specializing in
cosmology Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe, the cosmos. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', with the meaning of "a speaking of the wo ...
and
astrophysics Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline, James Keeler, said, astrophysics "seeks to ascertain the ...
. He is a Fellow of the
American Physical Society The American Physical Society (APS) is a not-for-profit membership organization of professionals in physics and related disciplines, comprising nearly fifty divisions, sections, and other units. Its mission is the advancement and diffusion of ...
and a professor and chair (2013-2023) of the Department of Physics and Astronomy at the
University of Kansas The University of Kansas (KU) is a public research university with its main campus in Lawrence, Kansas, United States. Two branch campuses are in the Kansas City metropolitan area on the Kansas side: the university's medical school and hospital ...
.


Education

Feldman graduated from the
University of California at Santa Cruz The University of California, Santa Cruz (UC Santa Cruz or UCSC) is a public land-grant research university in Santa Cruz, California, United States. It is one of the ten campuses in the University of California system. Located in Monterey Bay, ...
in 1983. He got his PhD at
Stony Brook University Stony Brook University (SBU), officially the State University of New York at Stony Brook, is a public university, public research university in Stony Brook, New York, United States, on Long Island. Along with the University at Buffalo, it is on ...
in NY, 1989 working with
Robert Brandenberger Robert H. Brandenberger (born 1956) is a Swiss-Canadian theoretical cosmologist and a professor of physics at McGill University in Montreal, Quebec, Canada. Biography Brandenberger completed his undergraduate degree at ETH Zurich, in Switzerla ...
. He was then a postdoc at the
Canadian Institute for Theoretical Astrophysics The Canadian Institute for Theoretical Astrophysics (CITA) is a national research institute funded by the Natural Sciences and Engineering Research Council, located at the University of Toronto in Toronto, Ontario, Canada. CITA's mission is "to f ...
, Toronto, 1989–91, a research fellow at the
University of Michigan The University of Michigan (U-M, U of M, or Michigan) is a public university, public research university in Ann Arbor, Michigan, United States. Founded in 1817, it is the oldest institution of higher education in the state. The University of Mi ...
1991-94 and a Prof. Research in the Physics Department at
Princeton University Princeton University is a private university, private Ivy League research university in Princeton, New Jersey, United States. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial ...
1994–96.


Research career

Hume has been a researcher in the study of the large-scale
peculiar velocity Peculiar motion or peculiar velocity refers to the velocity of an object relative to a ''rest frame''—usually a frame in which the average velocity of some objects is zero. Galactic astronomy In galactic astronomy, peculiar motion refers to t ...
field for the past two decades. His explanation of the systematic errors,
aliasing In signal processing and related disciplines, aliasing is a phenomenon that a reconstructed signal from samples of the original signal contains low frequency components that are not present in the original one. This is caused when, in the ori ...
and incomplete cancellations of small-scale
noise Noise is sound, chiefly unwanted, unintentional, or harmful sound considered unpleasant, loud, or disruptive to mental or hearing faculties. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrat ...
masquerading as large-scale signal lead to the reemergence of peculiar velocities as a premier tool in our arsenal to probe the dynamics and statistics of the
large-scale structure of the Universe The observable universe is a spherical region of the universe consisting of all matter that can be observed from Earth; the electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of th ...
. He developed a formalism to optimize the determination of cosmic flows from
proper distance Proper length or rest length is the length of an object in the object's rest frame. The measurement of lengths is more complicated in the theory of relativity than in classical mechanics. In classical mechanics, lengths are measured based on t ...
surveys and enabled for the first time direct comparison of independent surveys and cosmological models as a function of scale, thus establishing the cosmological significance of flow probes. His work has led to many widely cited results (such as a nearly 3-sigma flows on 100 Mpc/h scales), renewed discussion of imposing flow constraints on cosmological models and the redesign of proper distance surveys. He is the coauthor of two recent papers that brought back this field from a decade with no new data (with over 300 and 200 citations, respectively). Hume was a coauthor of the best-cited article on cosmological perturbations (>4000 citations) developing a gauge invariant formalism that is widely considered to be the gold standard in this sub- discipline. His seminal work on the approximation of the matter power spectrum from redshift surveys (>1000 citations) has opened the door to a whole industry of cosmological probes and N-point functions determination in Fourier space. He was a coauthor on the "Loitering Universe" series of papers that predicted an accelerating universe as a solution to the age problem in 1992 and which included a scalar field that acted like an effective
cosmological constant In cosmology, the cosmological constant (usually denoted by the Greek capital letter lambda: ), alternatively called Einstein's cosmological constant, is a coefficient that Albert Einstein initially added to his field equations of general rel ...
or a
quintessence Quintessence, or quintessential, or fifth essence, may refer to: Cosmology * Aether (classical element), in medieval cosmology and science, the fifth element that fills the universe beyond the terrestrial sphere * Quintessence (physics), a hypo ...
field years before the supernovae type IA results. He worked extensively on the constraints on galaxy bias, matter density, and primordial non-Gaussianity in
redshift survey In astronomy, a redshift survey is a astronomical surveys, survey of a section of the sky to measure the redshift of astronomical objects: usually galaxies, but sometimes other objects such as galaxy clusters or quasars. Using Hubble's law, the ...
s and his detection of the bispectrum signal was the first observational confirmation of the
Gravitational Instability The key idea in explaining the way in which structures evolve in the universe is gravitational instability. If material is to be brought together to form structures, then a long-range force is required, and gravity is the only known possibility. ...
Model. He helped develop an
artificial neural network In machine learning, a neural network (also artificial neural network or neural net, abbreviated ANN or NN) is a computational model inspired by the structure and functions of biological neural networks. A neural network consists of connected ...
formalism to interpolate the fully non-linear power spectrum of matter fluctuation and provided the community with a fast and accurate (<1% errors) software to determine the non-linear power spectrum given an input cosmology. His APS Fellow Citation reads:


Public activities

He travels widely for presentations to a diverse array of groups, from elementary to high school students to churches, interest groups, legislators and professional societies. He became involved in the Creationism/Intelligent Design in Kansas in 1999 when the nearly successful attempts of various fundamentalist groups to force the teaching of religion in public schools began in earnest. Hume was one of the leaders of a group of academics and educators that addressed, publicized and confronted the issue head on by organizing conferences, public forums and workshops, and through political advocacy including testimonials to the Kansas legislatures, providing high school science teachers with the tools and knowledge to discuss these issues locally to parents, students and the interested public.


References

{{DEFAULTSORT:Feldman, Hume Living people Year of birth missing (living people) Physical cosmology University of Kansas faculty American physicists University of California, Santa Cruz alumni Stony Brook University alumni University of Michigan fellows Fellows of the American Physical Society