Hermann Nicolai
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Hermann Nicolai (born 11 July 1952 in Friedberg) is a German theoretical physicist and director emeritus at the
Max Planck Institute for Gravitational Physics The Max Planck Institute for Gravitational Physics (Albert Einstein Institute) is a Max Planck Institute whose research is aimed at investigating Einstein's theory of relativity and beyond: Mathematics, quantum gravity, astrophysical relativity ...
in Potsdam-Golm.


Education and career

At
Karlsruhe Institute of Technology The Karlsruhe Institute of Technology (KIT; ) is both a German public research university in Karlsruhe, Baden-Württemberg, and a research center of the Helmholtz Association. KIT was created in 2009 when the University of Karlsruhe (), founde ...
, Hermann Nicolai, beginning in 1971, studied
physics Physics is the scientific study of matter, its Elementary particle, 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 whi ...
and
mathematics Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many ar ...
with a ''
Diplom A ''Diplom'' (, from ) is an academic degree in the German-speaking countries Germany, Austria, and Switzerland and a similarly named degree in some other European countries including Albania, Bulgaria, Belarus, Bosnia and Herzegovina, Croatia ...
'' in 1975 with a doctorate in 1978 under the supervision of Julius Wess. At
Heidelberg University Heidelberg University, officially the Ruprecht Karl University of Heidelberg (; ), is a public research university in Heidelberg, Baden-Württemberg, Germany. Founded in 1386 on instruction of Pope Urban VI, Heidelberg is Germany's oldest unive ...
, Nicolai was from 1978 to 1979 an assistant in theoretical physics. From 1979 to 1986, he worked at
CERN The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in Meyrin, western suburb of Gene ...
in
Geneva Geneva ( , ; ) ; ; . is the List of cities in Switzerland, second-most populous city in Switzerland and the most populous in French-speaking Romandy. Situated in the southwest of the country, where the Rhône exits Lake Geneva, it is the ca ...
as a staff member in the theory department. In 1983 he received his
habilitation Habilitation is the highest university degree, or the procedure by which it is achieved, in Germany, France, Italy, Poland and some other European and non-English-speaking countries. The candidate fulfills a university's set criteria of excelle ...
at Heidelberg University. He was a professor (with civil service grade C3) of theoretical physics at Karlsruhe Institute of Technology from 1986 to 1988 and from 1988 to 1997 a professor (with civil service grade C4) of theoretical physics at the
University of Hamburg The University of Hamburg (, also referred to as UHH) is a public university, public research university in Hamburg, Germany. It was founded on 28 March 1919 by combining the previous General Lecture System ('':de:Allgemeines Vorlesungswesen, ...
. At the
Max Planck Institute for Gravitational Physics The Max Planck Institute for Gravitational Physics (Albert Einstein Institute) is a Max Planck Institute whose research is aimed at investigating Einstein's theory of relativity and beyond: Mathematics, quantum gravity, astrophysical relativity ...
, Nicolai was head of the department "Quantum Gravity and Unified Field Theories" and a director from 1997 to 2020, when he retired as director emeritus. He was a member of the editorial board of ''
Communications in Mathematical Physics ''Communications in Mathematical Physics'' is a peer-reviewed academic journal published by Springer. The journal publishes papers in all fields of mathematical physics, but focuses particularly in analysis related to condensed matter physics, sta ...
'' from 1993 to 1995. Then, from 1998 to 2003 the editor-in-chief of the journal ''
Classical and Quantum Gravity ''Classical and Quantum Gravity'' is a peer-reviewed journal that covers all aspects of gravitational physics and the theory of spacetime. The editor-in-chief is Susan Scott at The Australian National University. The journal's 2023 impact fact ...
'', and from 2006 to 2011 the editor-in-chief of the journal ''
General Relativity and Gravitation ''General Relativity and Gravitation'' is a monthly peer-reviewed scientific journal. It was established in 1970, and is published by Springer Science+Business Media under the auspices of the International Society on General Relativity and Gravita ...
''. In 1991, Nicolai received the Otto-Klung-Award (now called the Klung Wilhelmy Science Award), in 2010 the
Albert Einstein Medal The Albert Einstein Medal is an award presented by the Albert Einstein Society in Bern. First given in 1979, the award is presented to people for "scientific findings, works, or publications related to Albert Einstein" each year. Recipients ...
, and in 2013 the Gay-Lussac-Humboldt Prize. He was appointed an honorary professor at the
Humboldt University of Berlin The Humboldt University of Berlin (, abbreviated HU Berlin) is a public research university in the central borough of Mitte in Berlin, Germany. The university was established by Frederick William III on the initiative of Wilhelm von Humbol ...
and in 2005 at the
University of Hannover Leibniz University Hannover (), also known as the University of Hannover, is a public research university located in Hanover, Germany. Founded on 2 May 1831 as Higher Vocational School, the university has undergone six periods of renaming, its ...
.


Research

In the mid 1980s, Nicolai and Bernard de Wit developed the "''N'' = 8 supergravity theory", which arises from the dimensional reduction of the maximally supersymmetrical
eleven-dimensional supergravity In supersymmetry, eleven-dimensional supergravity is the theory of supergravity in the highest number of dimensions allowed for a supersymmetric theory. It contains a graviton, a gravitino, and a 3-form gauge field, with their interactions unique ...
to four space-time dimensions (''d'' = 4) and for which, from many plausible viewpoints, a maximal
supersymmetry Supersymmetry is a Theory, theoretical framework in physics that suggests the existence of a symmetry between Particle physics, particles with integer Spin (physics), spin (''bosons'') and particles with half-integer spin (''fermions''). It propo ...
has a supergravity theory with a
graviton In theories of quantum gravity, the graviton is the hypothetical 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 re ...
and no particle with a
spin Spin or spinning most often refers to: * Spin (physics) or particle spin, a fundamental property of elementary particles * Spin quantum number, a number which defines the value of a particle's spin * Spinning (textiles), the creation of yarn or thr ...
greater than 2. In the 2000s, Nicolai and colleagues investigated the behavior of gravitational equations close to a
gravitational singularity A gravitational singularity, spacetime singularity, or simply singularity, is a theoretical condition in which gravity is predicted to be so intense that spacetime itself would break down catastrophically. As such, a singularity is by defini ...
such as the
Big Bang The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. Various cosmological models based on the Big Bang concept explain a broad range of phenomena, including th ...
; these investigation lead to models with chaotic
dynamical billiards A dynamical billiard is a dynamical system in which a particle alternates between free motion (typically as a straight line) and specular reflections from a boundary. When the particle hits the boundary it reflects from it Elastic collision, witho ...
, in the case of classical
general relativity theory General relativity, also known as the general theory of relativity, and as Einstein's theory of gravity, is the differential geometry, geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of grav ...
in three dimensions. In the case of eleven-dimensional supergravity, these investigations to ten-dimensional "cosmological billiards", and the infinite-dimensional hyperbolic Kac Moody algebra E_ appears as a symmetry. E_ contains the largest finite-dimensional exceptional semi-simple complex
Lie algebra In mathematics, a Lie algebra (pronounced ) is a vector space \mathfrak g together with an operation called the Lie bracket, an alternating bilinear map \mathfrak g \times \mathfrak g \rightarrow \mathfrak g, that satisfies the Jacobi ident ...
E_8, which has been studied as a candidate for a
grand unified theory A Grand Unified Theory (GUT) is any Mathematical model, model in particle physics that merges the electromagnetism, electromagnetic, weak interaction, weak, and strong interaction, strong fundamental interaction, forces (the three gauge theory, ...
(GUT]. Nicolai proposed a purely algebraic description of the universe in cosmological space-time regions near the singularity (within the
Planck time In particle physics and physical cosmology, Planck units are a system of units of measurement defined exclusively in terms of four universal physical constants: '' c'', '' G'', '' ħ'', and ''k''B (described further below). Expressing one of ...
) using the E_ -symmetry, whereby the space-time dimensions result as an
emergent phenomenon In philosophy, systems theory, science, and art, emergence occurs when a complex entity has properties or behaviors that its parts do not have on their own, and emerge only when they interact in a wider whole. Emergence plays a central role ...
. Nicolai has also done research on a special role for E_ in
M-Theory In physics, M-theory is a theory that unifies all Consistency, consistent versions of superstring theory. Edward Witten first conjectured the existence of such a theory at a string theory conference at the University of Southern California in 1 ...
. He and de Wit also constructed maximally gauged (''N'' = 16) supergravity theories in three dimensions and their symmetries.arXiv.org
/ref> Furthermore, Nicolai and colleagues examined generalizations of the variables of
loop quantum gravity Loop quantum gravity (LQG) is a theory of quantum gravity that incorporates matter of the Standard Model into the framework established for the intrinsic quantum gravity case. It is an attempt to develop a quantum theory of gravity based direc ...
to supergravity / string theory.


Selected publications

In addition to the publications cited in the footnotes: * * * * (over 950 citation) * *
arXiv.org
*
arXiv.org
*
arXiv.org
*
arXiv.org
* * * * * *
''Quantum gravity - the view from particle physics'', Prag 2013, arXiv.org


See also

*
Hierarchy problem In theoretical physics, the hierarchy problem is the problem concerning the large discrepancy between aspects of the weak force and gravity. There is no scientific consensus on why, for example, the weak force is 1024 times stronger than gravi ...
* Nicolai map


References


External links


Max Planck Institute for Gravitational Physics (homepage)
* {{DEFAULTSORT:Nicolai, Hermann 20th-century German physicists 21st-century German physicists German theoretical physicists Karlsruhe Institute of Technology alumni People associated with CERN Academic staff of the University of Hamburg 1952 births Living people Max Planck Institute directors