Katherine Freese

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Katherine Freese
Katherine Freese.jpg
Nationality German
Alma mater Princeton University, Columbia University, University of Chicago
Known for Dark matter, Dark stars, Dark energy, Inflation
Awards Simons Foundation Fellowship (2012)
Lilienfeld Prize (2019)
Scientific career
Fields Astrophysics, Cosmology
Institutions University of Michigan
Nordita, Stockholm University
Doctoral advisor David Schramm
Doctoral students Janna Levin

Katherine Freese is a theoretical astrophysicist and George Eugene Uhlenbeck Collegiate Professor of Physics at the University of Michigan in Ann Arbor. Starting in September 2014, she assumed the position of Director of Nordita, the Nordic Institute for Theoretical Physics, in Stockholm, and holds a position as Visiting Professor of Physics at Stockholm University. She is known for her work in theoretical cosmology at the interface of particle physics and astrophysics.

University of Michigan Public research university in Ann Arbor, Michigan, United States

The University of Michigan, often simply referred to as Michigan, is a public research university in Ann Arbor, Michigan. The university is Michigan's oldest; it was founded in 1817 in Detroit, as the Catholepistemiad, or University of Michigania, 20 years before the territory became a state. The school was moved to Ann Arbor in 1837 onto 40 acres (16 ha) of what is now known as Central Campus. Since its establishment in Ann Arbor, the university campus has expanded to include more than 584 major buildings with a combined area of more than 34 million gross square feet spread out over a Central Campus and North Campus, two regional campuses in Flint and Dearborn, and a Center in Detroit. The university is a founding member of the Association of American Universities.

Nordic Institute for Theoretical Physics research institute

The Nordic Institute for Theoretical Physics, or Nordita, is an international organisation for research in theoretical physics. It was established in 1957 by Niels Bohr and the Swedish physicist Torsten Gustafson. Nordita was originally located at the Niels Bohr Institute in Copenhagen (Denmark), but moved to the AlbaNova University Centre in Stockholm (Sweden) on 1 January 2007. The main research areas at Nordita are astrophysics, hard and soft condensed matter physics, and high-energy physics.

Stockholm University state university of Stockholm, Sweden

Stockholm University is a public university in Stockholm, Sweden, founded as a college in 1878, with university status since 1960. Stockholm University has two scientific fields: the natural sciences and the humanities/social sciences. With over 34,000 students at four different faculties: law, humanities, social sciences, and natural sciences, it is one of the largest universities in Scandinavia. The institution is regarded as one of the top 100 universities in the world by the Academic Ranking of World Universities (ARWU).


Education and Academic Career

Freese received her BA from Princeton University, one of the first women to major in physics at Princeton. [1] She obtained her MA from Columbia University, and her PhD at the University of Chicago from advisor David Schramm. After postdoctoral fellowships at Harvard University, at the Kavli Institute for Theoretical Physics at University of California, Santa Barbara, and as a Presidential Fellow at the University of California, Berkeley, she became an Assistant Professor at MIT. She moved to the University of Michigan where she is now George E. Uhlenbeck Professor of Physics. From 2007-2014 she was Associate Director of the Michigan Center for Theoretical Physics.

Princeton University is a private Ivy League research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the nine colonial colleges chartered before the American Revolution. The institution moved to Newark in 1747, then to the current site nine years later, and renamed itself Princeton University in 1896.

Columbia University Private Ivy League research university in New York City

Columbia University is a private Ivy League research university in Upper Manhattan, New York City. Established in 1754, Columbia is the oldest institution of higher education in New York and the fifth-oldest institution of higher learning in the United States. It is one of nine colonial colleges founded prior to the Declaration of Independence, seven of which belong to the Ivy League. It has been ranked by numerous major education publications as among the top ten universities in the world.

University of Chicago Private research university in Chicago, Illinois, United States

The University of Chicago is a private research university in Chicago, Illinois. Founded in 1890 by John D. Rockefeller, the school is located on a 217-acre campus in Chicago's Hyde Park neighborhood, near Lake Michigan. The University of Chicago holds top-ten positions in various national and international rankings.


Freese has contributed to early research on dark matter and dark energy. She was one of the first to propose ways to discover dark matter. [2] Her idea of indirect detection in the Earth is being pursued by the IceCube Neutrino Observatory experiment, [3] and the "wind" of dark matter particles felt as the Earth orbits the Milky Way (work with David Spergel) is being searched for in worldwide experiments. Her work decisively ruled out MACHO (Massive compact halo object) dark matter in favor of WIMPs (weakly interacting massive particles). [4] She has proposed a model known as "Cardassian expansion," in which dark energy is replaced with a modification of Einstein's equations. [5] Recently she proposed a new theoretical type of star, called a dark star, powered by dark matter annihilation rather than fusion [6]

Dark matter Hypothetical form of matter comprising most of the matter in the universe

Dark matter is a hypothetical form of matter that is thought to account for approximately 85% of the matter in the universe and about a quarter of its total energy density. The majority of dark matter is thought to be non-baryonic in nature, possibly being composed of some as-yet undiscovered subatomic particles. Its presence is implied in a variety of astrophysical observations, including gravitational effects that cannot be explained by accepted theories of gravity unless more matter is present than can be seen. For this reason, most experts think dark matter to be ubiquitous in the universe and to have had a strong influence on its structure and evolution. Dark matter is called dark because it does not appear to interact with observable electromagnetic radiation, such as light, and is thus invisible to the entire electromagnetic spectrum, making it extremely difficult to detect using usual astronomical equipment.

Dark energy unknown property in cosmology that causes the expansion of the universe to accelerate.

In physical cosmology and astronomy, dark energy is an unknown form of energy which is hypothesized to permeate all of space, tending to accelerate the expansion of the universe. Dark energy is the most accepted hypothesis to explain the observations since the 1990s indicating that the universe is expanding at an accelerating rate.

IceCube Neutrino Observatory neutrinodetector in Antarktika

The IceCube Neutrino Observatory is a neutrino observatory constructed at the Amundsen–Scott South Pole Station in Antarctica. Its thousands of sensors are located under the Antarctic ice, distributed over a cubic kilometre.

Freese has also worked on the beginnings of the universe, including the search for a successful inflationary theory to kick off the Big Bang. Her natural inflation model [7] is a theoretically well-motivated variant of inflation; it uses axionic-type particles to provide the required flat potentials to drive the expansion. In 2013, observations made by the European Space Agency's Planck Satellite show that the framework of natural inflation matches the data. [8] She has studied the Ultimate fate of the universe, including the fate of life in the universe. [9] "

Big Bang The prevailing cosmological model for the observable universe

The Big Bang theory is the prevailing cosmological model for the observable universe from the earliest known periods through its subsequent large-scale evolution. The model describes how the universe expanded from a very high-density and high-temperature state, and offers a comprehensive explanation for a broad range of phenomena, including the abundance of light elements, the cosmic microwave background (CMB), large scale structure and Hubble's law. If the observed conditions are extrapolated backwards in time using the known laws of physics, the prediction is that just before a period of very high density there was a singularity which is typically associated with the Big Bang. Physicists are undecided whether this means the universe began from a singularity, or that current knowledge is insufficient to describe the universe at that time. Detailed measurements of the expansion rate of the universe place the Big Bang at around 13.8 billion years ago, which is thus considered the age of the universe. After its initial expansion, the universe cooled sufficiently to allow the formation of subatomic particles, and later simple atoms. Giant clouds of these primordial elements later coalesced through gravity, eventually forming early stars and galaxies, the descendants of which are visible today. Astronomers also observe the gravitational effects of dark matter surrounding galaxies. Though most of the mass in the universe seems to be in the form of dark matter, Big Bang theory and various observations seem to indicate that it is not made out of conventional baryonic matter but it is unclear exactly what it is made out of.

European Space Agency intergovernmental organisation dedicated to the exploration of space

The European Space Agency is an intergovernmental organisation of 22 member states dedicated to the exploration of space. Established in 1975 and headquartered in Paris, France, ESA has a worldwide staff of about 2,200 in 2018 and an annual budget of about €5.72 billion in 2019.

Ultimate fate of the universe topic in physical cosmology

The ultimate fate of the universe is a topic in physical cosmology, whose theoretical restrictions allow possible scenarios for the evolution and ultimate fate of the universe to be described and evaluated. Based on available observational evidence, deciding the fate and evolution of the universe have now become valid cosmological questions, being beyond the mostly untestable constraints of mythological or theological beliefs. Many possible dark futures have been predicted by rival scientific hypotheses, including that the universe might have existed for a finite and infinite duration, or towards explaining the manner and circumstances of its beginning.

Freese has served on the Board of the Kavli Institute for Theoretical Physics in Santa Barbara and the Board of the Aspen Center for Physics. From 2008-2012 she was a Councilor and Member of the Executive Committee of the American Physical Society, and from 2005-2008 she was a member of the Astronomy and Astrophysics Advisory Committee (AAAC). Currently she serves on the Board of the Oskar Klein Centre for Cosmoparticle Physics in Stockholm. In 2009 Freese was elected Fellow of the American Physical Society. She received a Simons Foundation Fellowship in Theoretical Physics. In September 2012 Freese was awarded an Honorary Doctorate (Honoris Causa) from the University of Stockholm.

Kavli Institute for Theoretical Physics research institute at the University of California, Santa Barbara

The Kavli Institute for Theoretical Physics (KITP) is a research institute of the University of California, Santa Barbara. KITP is one of the most renowned institutes for theoretical physics in the world, and brings theorists in physics and related fields together to work on topics at the forefront of theoretical science. The National Science Foundation has been the principal supporter of the Institute since it was founded as the Institute for Theoretical Physics in 1979. In a 2007 article in the Proceedings of the National Academy of Sciences, KITP was given the highest impact index in a comparison of nonbiomedical research organizations across the U.S.

Aspen Center for Physics

The Aspen Center for Physics is a non-profit Center for research in Physics based in Aspen, Colorado, United States. The Center organizes workshops and conferences to facilitate interactions among research physicists.

The American Physical Society (APS) is the world's second largest organization of physicists. The Society publishes more than a dozen scientific journals, including the prestigious Physical Review and Physical Review Letters, and organizes more than twenty science meetings each year. APS is a member society of the American Institute of Physics.

Students who obtained their PhD's from Freese include Janna Levin, author and professor in astronomy and physics at Barnard College and Jay Jubas, Senior Partner at McKinsey & Company, Telecoms, Media & Technology.

Janna J. Levin is an American theoretical cosmologist and an associate professor of physics and astronomy at Barnard College. She earned a PhD in theoretical physics at the Massachusetts Institute of Technology in 1993, and a Bachelor of Science in astronomy and physics with a concentration in philosophy at Barnard College in 1988, where she graduated Phi Beta Kappa. Much of her work deals with looking for evidence to support the proposal that our universe might be finite in size due to its having a nontrivial topology. Other work includes black holes and chaos theory. She joined the faculty at Barnard College in January 2004 and is currently the recipient Tow Professor grant.

Barnard College private womens liberal arts college in the United States

Barnard College is a private women's liberal arts college located in Manhattan, New York City. Founded in 1889 by Annie Nathan Meyer, who named it after Columbia University's 10th president, Frederick Barnard, it is one of the oldest women's colleges in the world. The acceptance rate of the Class of 2023 was 11.3%, the most selective and diverse class in the college's 129-year history.

McKinsey & Company is an American worldwide management consulting firm. It conducts qualitative and quantitative analysis to evaluate management decisions across public and private sectors. Widely considered the most prestigious management consultancy, McKinsey's clientele includes 80% of the world's largest corporations, and an extensive list of governments and non-profit organisations. More current and former Fortune 500 C.E.O.s are alumni of McKinsey than of any other company, a list including Google C.E.O. Sundar Pichai, Morgan Stanley C.E.O. James P. Gorman, and many more. McKinsey publishes the McKinsey Quarterly since 1964, funds the McKinsey Global Institute research organization, publishes reports on management topics, and has authored many influential books on management. Its practices of confidentiality, influence on business practices, and corporate culture have experienced a polarizing reception.

Personal life

Freese was born in Freiburg, Germany, to Ernst Freese and Elisabeth Bautz Freese. At age nine months she emigrated to the United States. Her cousin Anja Freese, a German actor, currently resides in Los Angeles.

In addition to contributions in academia and research, Dr. Freese has written a comprehensive review for the general educated public on dark matter and energy as they relate to recent research in cosmology and particle physics, titled The Cosmic Cocktail: Three Parts Dark Matter (Science Essentials, 2014, ISBN   0691153353). The book is partly autobiographical. Katherine covers the contributions of Fritz Zwicky, for example, who was recently profiled as "the most important astronomer you've never heard of" and "the father of dark matter" on Cosmos: A Spacetime Odyssey.

Related Research Articles

Neutrino Elementary particle with very low mass that interacts only via the weak force and gravity

A neutrino is a fermion that interacts only via the weak subatomic force and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small (-ino) that it was long thought to be zero. The mass of the neutrino is much smaller than that of the other known elementary particles. The weak force has a very short range, the gravitational interaction is extremely weak, and neutrinos, as leptons, do not participate in the strong interaction. Thus, neutrinos typically pass through normal matter unimpeded and undetected.

Weakly interacting massive particles (WIMPs) are hypothetical particles that are thought to constitute dark matter. There exists no clear definition of a WIMP, but broadly, a WIMP is a new elementary particle which interacts via gravity and any other force, potentially not part of the standard model itself, which is as weak as or weaker than the weak nuclear force, but also non-vanishing in its strength. A WIMP must also have been produced thermally in the early Universe, similarly to the particles of the standard model according to Big Bang cosmology, and usually will constitute cold dark matter. Obtaining the correct abundance of dark matter today via thermal production requires a self-annihilation cross section of , which is roughly what is expected for a new particle in the 100 GeV mass range that interacts via the electroweak force. Because supersymmetric extensions of the standard model of particle physics readily predict a new particle with these properties, this apparent coincidence is known as the "WIMP miracle", and a stable supersymmetric partner has long been a prime WIMP candidate. However, recent null results from direct-detection experiments along with the failure to produce evidence of supersymmetry in the Large Hadron Collider (LHC) experiment has cast doubt on the simplest WIMP hypothesis. Experimental efforts to detect WIMPs include the search for products of WIMP annihilation, including gamma rays, neutrinos and cosmic rays in nearby galaxies and galaxy clusters; direct detection experiments designed to measure the collision of WIMPs with nuclei in the laboratory, as well as attempts to directly produce WIMPs in colliders, such as the LHC.

Standard Model theory of particle physics

The Standard Model of particle physics is the theory describing three of the four known fundamental forces in the universe, as well as classifying all known elementary particles. It was developed in stages throughout the latter half of the 20th century, through the work of many scientists around the world, with the current formulation being finalized in the mid-1970s upon experimental confirmation of the existence of quarks. Since then, confirmation of the top quark (1995), the tau neutrino (2000), and the Higgs boson (2012) have added further credence to the Standard Model. In addition, the Standard Model has predicted various properties of weak neutral currents and the W and Z bosons with great accuracy.

Wilkinson Microwave Anisotropy Probe space observatory

The Wilkinson Microwave Anisotropy Probe (WMAP), originally known as the Microwave Anisotropy Probe (MAP), was a spacecraft operating from 2001 to 2010 which measured temperature differences across the sky in the cosmic microwave background (CMB) – the radiant heat remaining from the Big Bang. Headed by Professor Charles L. Bennett of Johns Hopkins University, the mission was developed in a joint partnership between the NASA Goddard Space Flight Center and Princeton University. The WMAP spacecraft was launched on June 30, 2001 from Florida. The WMAP mission succeeded the COBE space mission and was the second medium-class (MIDEX) spacecraft in the NASA Explorers program. In 2003, MAP was renamed WMAP in honor of cosmologist David Todd Wilkinson (1935–2002), who had been a member of the mission's science team. After nine years of operations, WMAP was switched off in 2010, following the launch of the more advanced Planck spacecraft by ESA in 2009.

Alan Guth American theoretical physicist and cosmologist

Alan Harvey Guth is an American theoretical physicist and cosmologist. Guth has researched elementary particle theory. He is Victor Weisskopf Professor of Physics in the Massachusetts Institute of Technology. Along with Alexei Starobinsky and Andrei Linde, he won the 2014 Kavli Prize “for pioneering the theory of cosmic inflation.”

David Schramm (astrophysicist) American astrophysicist

David Norman Schramm was an American astrophysicist and educator, and one of the world's foremost experts on the Big Bang theory. Schramm was a pioneer in establishing particle astrophysics as a vibrant research field. He was particularly well known for the study of Big Bang nucleosynthesis and its use as a probe of dark matter and of neutrinos. He also made important contributions to the study of cosmic rays, supernova explosions, heavy-element nucleosynthesis, and nuclear astrophysics generally.

Lambda-CDM model Model of big-bang cosmology

The ΛCDM or Lambda-CDM model is a parametrization of the Big Bang cosmological model in which the universe contains three major components: first, a cosmological constant denoted by Lambda and associated with dark energy; second, the postulated cold dark matter ; and third, ordinary matter. It is frequently referred to as the standard model of Big Bang cosmology because it is the simplest model that provides a reasonably good account of the following properties of the cosmos:

Paul Steinhardt American cosmologist

Paul Joseph Steinhardt is an American theoretical physicist and cosmologist who is currently the Albert Einstein Professor in Science at Princeton University.

Physics beyond the Standard Model Theories attempting to explain the deficiencies of the Standard Model, Quantum field theory and general relativity

Physics beyond the Standard Model (BSM) refers to the theoretical developments needed to explain the deficiencies of the Standard Model, such as the strong CP problem, neutrino oscillations, matter–antimatter asymmetry, and the nature of dark matter and dark energy. Another problem lies within the mathematical framework of the Standard Model itself: the Standard Model is inconsistent with that of general relativity, to the point where one or both theories break down under certain conditions.

Warm dark matter (WDM) is a hypothesized form of dark matter that has properties intermediate between those of hot dark matter and cold dark matter, causing structure formation to occur bottom-up from above their free-streaming scale, and top-down below their free streaming scale. The most common WDM candidates are sterile neutrinos and gravitinos. The WIMPs, when produced non-thermally could be candidates for warm dark matter. In general, however the thermally produced WIMPs are cold dark matter candidates.

David Nathaniel Spergel, is an American theoretical astrophysicist and Princeton University professor known for his work on the WMAP mission. Spergel is a MacArthur Fellow. He is a member of the NASA Advisory Council and is chair of the Space Studies Board. He was once the W.M. Keck distinguished visiting professor at the Institute for Advanced Study in Princeton, New Jersey. He was part of the team that originated the WMAP mission and designed the spacecraft, and has worked on deciphering the data that it beams back from space. Spergel is playing a leading role in developing the WFIRST, a multibillion-dollar space mission planned for launch in the mid-2020s. Spergel is the Charles A Young Professor of Astronomy and a member of the National Academy of Sciences. Spergel is the Founding Director of the Center for Computational Astrophysics. He shared the 2010 Shaw Prize in astronomy with Charles L. Bennett and Lyman Alexander Page, Jr. for their work on WMAP. He shared the 2015 Dannie Heineman Prize with Marc Kamionkowski "for their outstanding contributions to the investigation of the fluctuations of the cosmic microwave background that have led to major breakthroughs in our understanding of the universe".

A dark star is a type of star that may have existed early in the universe before conventional stars were able to form. The stars would be composed mostly of normal matter, like modern stars, but a high concentration of neutralino dark matter within them would generate heat via annihilation reactions between the dark-matter particles. This heat would prevent such stars from collapsing into the relatively compact sizes of modern stars and therefore prevent nuclear fusion among the normal matter atoms from being initiated.

Light dark matter Dark matter weakly interacting massive particles candidates with masses less than 1 GeV

In astronomy and cosmology, light dark matter are dark matter weakly interacting massive particles (WIMPS) candidates with masses less than 1 GeV. These particles are heavier than warm dark matter and hot dark matter, but are lighter than the traditional forms of cold dark matter. The Lee-Weinberg bound limits the mass of the favored dark matter candidate, WIMPs, that interact via the weak interaction to GeV. This bound arises as follows. The lower the mass of WIMPs is, the lower the annihilation cross section, which is of the order , where m is the WIMP mass and M the mass of the Z-boson. This means that low mass WIMPs, which would be abundantly produced in the early universe, freeze out much earlier and thus at a higher temperature, than higher mass WIMPs. This leads to a higher relic WIMP density. If the mass is lower than GeV the WIMP relic density would overclose the universe.

Kim Jihn-eui Korean Physicist

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Manfred Lindner German physicist

Manfred Lindner is a German physicist and director at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. He conducts research in neutrino physics, dark matter and physics beyond the standard model of particle physics.

Yasunori Nomura theoretical physicist

Yasunori Nomura is a theoretical physicist working on particle physics, quantum gravity, and cosmology. He is a Professor of Physics at University of California, Berkeley, a Senior Faculty Scientist at Lawrence Berkeley National Laboratory, and a Principal Investigator at Kavli Institute for the Physics and Mathematics of the Universe. Since 2015, he has been the Director of the Berkeley Center for Theoretical Physics.

Hitoshi Murayama Japanese physicist

Hitoshi Murayama (村山斉) is a Japanese-born physicist with notable contributions in the fields of particle physics and cosmology. He is currently a professor at University of California, Berkeley, and Director of the Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo.

Dan Hooper

Daniel Wayne Hooper is an American cosmologist and particle physicist specializing in the areas of dark matter, cosmic rays, and neutrino astrophysics. He is a Senior Scientist at Fermi National Accelerator Laboratory and an Associate Professor of Astronomy and Astrophysics at the University of Chicago.


  1. Renken, Elena (2016-09-20). "University of Michigan professor delves into dark matter". Brown Daily Herald. Retrieved 2018-02-03.
  2. Drukier, Andrzej; Katherine Freese; David Spergel. "Detecting Cold Dark Matter Candidates". Physical Review D . 33 (12): 3495–3508. Bibcode:1986PhRvD..33.3495D. doi:10.1103/PhysRevD.33.3495.
  3. Freese, Katherine. "Can Scalar Neutrinos or Massive Dirac Neutrinos be the Missing Mass". Physics Letters. B167 (3): 295–300. Bibcode:1986PhLB..167..295F. doi:10.1016/0370-2693(86)90349-7.
  4. James Glanz, New York Times, Feb. 2000, , "In the Dark Matter Wars, WIMPs beat MACHOs",
  5. Dennis Overbye, New York Times, Nov. 2003, , "What is Gravity, Really?"
  6. Freese, Katherine; Bodenheimer, Peter; Spolyar, Douglas; Gondolo, Paolo. "Stellar Structure of Dark Stars: A First Phase of Stellar Evolution Resulting from Dark Matter Annihilation". The Astrophysical Journal . 685 (2): L101–L104. arXiv: 0806.0617 . Bibcode:2008ApJ...685L.101F. doi:10.1086/592685.
  7. Freese, Katherine; Joshua Frieman; Angela Olinto. "Natural Inflation with Pseudo-Nambu Goldstone Bosons". Physical Review Letters . 65: 3233–3236. Bibcode:1990PhRvL..65.3233F. doi:10.1103/PhysRevLett.65.3233.
  8. Collaboration, Planck. "Planck 2013 Results XXII: Constraints on Inflation". arXiv: 1303.5082 . Bibcode:2014A&A...571A..22P. doi:10.1051/0004-6361/201321569.
  9. Philip Ball, , "Never Say Die", New Scientist , Aug. 2002