Mustapha Ishak-Boushaki is a

theoretical physicist Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. This is in contrast to experimental physics, which uses experimen ...

cosmologist Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', and in 1731 taken up in Latin by German philosopher ...

and professor at the

University of Texas at Dallas The University of Texas at Dallas (UTD or UT Dallas) is a public research university in Richardson, Texas. It is one of the largest public universities in the Dallas area and the northernmost institution of the University of Texas system. It wa ...

. He is known for his contributions to the studies of

cosmic acceleration Observations show that the expansion of the universe is accelerating, such that the velocity at which a distant galaxy recedes from the observer is continuously increasing with time. The accelerated expansion of the universe was discovered during ...

and

dark energy In physical cosmology and astronomy, dark energy is an unknown form of energy that affects the universe on the largest scales. The first observational evidence for its existence came from measurements of supernovas, which showed that the univer ...

gravitational lensing A gravitational lens is a distribution of matter (such as a galaxy cluster, cluster of galaxies) between a distant light source and an observer that is capable of bending the light from the source as the light travels toward the observer. This ...

, and testing

alternatives to general relativity Founded in 1994, Alternatives, Action and Communication Network for International Development, is a non-governmental, international solidarity organization based in Montreal, Quebec, Canada. Alternatives works to promote justice and equality a ...

; as well as his authorship of ''Testing General Relativity in Cosmology'', a review article published in ''

Living Reviews in Relativity ''Living Reviews in Relativity'' is a peer-reviewed open-access scientific journal publishing reviews on relativity in the areas of physics and astrophysics. It was founded by Bernard Schutz and published at the Max Planck Institute for Gravit ...

''. He was elected in 2021 as Fellow of

American Association for the Advancement of Science (AAAS) The American Association for the Advancement of Science (AAAS) is an American international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific respons ...

with the quote: "For distinguished contributions to the field of theoretical cosmology, particularly for testing modifications to general relativity at cosmological scales, and for sustained excellence in teaching and mentoring of students."

Education and academic background

Mustapha Ishak-Boushaki was born in

Algeria ) , image_map = Algeria (centered orthographic projection).svg , map_caption = , image_map2 = , capital = Algiers , coordinates = , largest_city = capital , relig ...

, where he grew up and completed his pre-university studies in the city of Bouira. He moved to

Montreal Montreal ( ; officially Montréal, ) is the List of the largest municipalities in Canada by population, second-most populous city in Canada and List of towns in Quebec, most populous city in the Provinces and territories of Canada, Canadian ...

in 1987. In 1994, he received his undergraduate degree in

computer science Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical discipli ...

at the

University of Quebec at Montreal A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, the ...

, followed by an additional undergraduate degree in

physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...

from the

University of Montreal A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, the ...

in 1998. He then attended

Queen's University at Kingston Queen's University at Kingston, commonly known as Queen's University or simply Queen's, is a public research university in Kingston, Ontario, Canada. Queen's holds more than of land throughout Ontario and owns Herstmonceux Castle in East Suss ...

where in 2003 he completed his PhD in

general relativity General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics ...

and theoretical cosmology. His graduate work included studied on inhomogeneous cosmologies,

wormhole A wormhole (Einstein-Rosen bridge) is a hypothetical structure connecting disparate points in spacetime, and is based on a special Solutions of the Einstein field equations, solution of the Einstein field equations. A wormhole can be visualize ...

exact solutions in general relativity In general relativity, an exact solution is a solution of the Einstein field equations whose derivation does not invoke simplifying assumptions, though the starting point for that derivation may be an idealized case like a perfectly spherical sh ...

of compact objects (such as

neutron star A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich. Except for black holes and some hypothetical objects (e.g. white ...

s), and an inverse approach to the

Einstein field equations In the general theory of relativity, the Einstein field equations (EFE; also known as Einstein's equations) relate the geometry of spacetime to the distribution of matter within it. The equations were published by Einstein in 1915 in the form ...

. Following the completion of his graduate studies, Ishak-Boushaki began work as a

research associate Research associates are researchers (scholars and professionals) that usually have an advanced degree beyond a Master's degree. In some universities/research institutes, such as Harvard/Harvard Medical School/Harvard School of Public Health, the ...

Princeton University Princeton University is a private university, private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial Colleges, fourth-oldest ins ...

until later entering a professorship at the

in 2005. While at the University of Texas at Dallas, he formed an active group of cosmologists and astrophysicists, and was received the Outstanding Teacher of the Year Award in the years 2007 and 2018, as well as the University President's Excellence in Teaching Award He is an active member of the Dark Energy Science Collaboration: a collaboration of the Legacy Survey of Space and Time, as well as the

Dark Energy Spectroscopic Instrument The Dark Energy Spectroscopic Instrument (DESI) is a scientific research instrument for conducting spectrographic astronomical surveys of distant galaxies. Its main components are a focal plane containing 5,000 fiber-positioning robots, and a bank ...

, both dedicated to constraining the properties of

and

, as well as testing the nature of gravity at cosmic scales.

Research and career

Mustapha Ishak-Boushaki's work involves research in the subjects of the origin and cause of

and the

associated with it, testing

at cosmological scales, the application of

gravitational lens A gravitational lens is a distribution of matter (such as a cluster of galaxies) between a distant light source and an observer that is capable of bending the light from the source as the light travels toward the observer. This effect is known ...

ing to cosmology, intrinsic alignment of galaxies, and inhomogeneous cosmological models. In 2005, Ishak-Boushaki and collaborators proposed a procedure to distinguish between dark energy and modification to general relativity at cosmological scales as a cause of cosmic acceleration. The idea was based on the fact that cosmic acceleration affects both the expansion rate and the growth rate of large-scale structures in the universe. These two effects must be consistent one with another since they are based on the same underlying theory of gravity. The publication was one of the first to: (1) contrast dark energy versus modified gravity as cause of cosmic acceleration, (2) use inconsistencies between cosmological parameters to test gravitational theory at cosmological scales. He and collaborators wrote then a series of publications on testing general relativity at cosmological scales and his work on the subject was recognized by an invitation to write in 2018 a review article on the current state of research in the field of testing

in the journal ''

''. Ishak-Boushaki and collaborators made a first detection of the large-scale intrinsic alignment of galaxies of type "intrinsic shear – gravitational shear" using a spectroscopic galaxy sample from the

Sloan Digital Sky Survey The Sloan Digital Sky Survey or SDSS is a major multi-spectral imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project began in 2000 a ...

. He and collaborators also made a first detection of these intrinsic alignments using a self-calibration method in the photometric galaxy sample in Kilo-Degree Survey. Ishak-Boushaki and collaborator wrote a review article on the intrinsic alignment of galaxies and its impact on weak gravitational lensing. Ishak-Boushaki and a collaborator proposed a new mathematical measure of inconsistency between cosmological datasets called the index of inconsistency (IOI) as well as a novel Baysian interpretation of the level of significance of such measures.

Awards and honors

References

External links

Mustapha Ishak-Boushaki's personal websiteMustapha Ishak-Boushaki's papers recorded in INSPIRE-HEP
* {{DEFAULTSORT:Ishak-Boushaki, Mustapha Kabyle people American astrophysicists American cosmologists Algerian astrophysicists 21st-century American physicists 1967 births Living people Theoretical physicists Algerian emigrants to Canada Algerian expatriates in the United States Université du Québec à Montréal alumni Université de Montréal alumni Queen's University at Kingston alumni Princeton University alumni Princeton University faculty University of Texas at Dallas faculty 20th-century Algerian physicists 21st-century Algerian physicists Algerian science writers Mustapha Naturalized citizens of the United States 21st-century Algerian inventors Fellows of the American Physical Society