# Hermann Nicolai

Hermann Nicolai (born 11 July 1952 in Friedberg) is a German theoretical physicist and director emeritus at the Max Planck Institute for Gravitational Physics in Potsdam-Golm.

## Education and career

At Karlsruhe Institute of Technology, Hermann Nicolai, beginning in 1971, studied physics and mathematics with a Diplom in 1975 with a doctorate in 1978 under the supervision of Julius Wess. At Heidelberg University, Nicolai was from 1978 to 1979 an assistant in theoretical physics. From 1979 to 1986, he worked at CERN in Geneva as a staff member in the theory department. In 1983 he received his habilitation 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. At the Max Planck Institute for Gravitational Physics, 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 from 1993 to 1995. Then, from 1998 to 2003 the editor-in-chief of the journal Classical and Quantum Gravity, and from 2006 to 2011 the editor-in-chief of the journal General Relativity and Gravitation.
In 1991, Nicolai received the Otto-Klung-Award (now called the Klung Wilhelmy Science Award), in 2010 the Albert Einstein Medal, and in 2013 the Gay-Lussac-Humboldt Prize. He was appointed an honorary professor at the Humboldt University of Berlin and in 2005 at the University of Hannover.

## 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 to four space-time dimensions (d = 4) and for which, from many plausible viewpoints, a maximal supersymmetry has a supergravity theory with a graviton and no particle with a spin greater than 2.
In the 2000s, Nicolai and colleagues investigated the behavior of gravitational equations close to a gravitational singularity such as the Big Bang; these investigation lead to models with chaotic dynamical billiards, in the case of classical general relativity theory 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 $E_{10}$ appears as a symmetry. $E_{10}$ contains the largest finite-dimensional exceptional semi-simple complex Lie algebra $E_{8}$, which has been studied as a candidate for a grand unified theory (GUT]. Nicolai proposed a purely algebraic description of the universe in cosmological space-time regions near the singularity (within the Planck time) using the $E_{10}$-symmetry, whereby the space-time dimensions result as an emergent phenomenon.
Nicolai has also done research on a special role for $E_{10}$ in M-Theory.
He and de Wit also constructed maximally gauged (N = 16) supergravity theories in three dimensions and their symmetries. Furthermore, Nicolai and colleagues examined generalizations of the variables of loop quantum gravity to supergravity / string theory.

## Selected publications

In addition to the publications cited in the footnotes:
* Nicolai, H. (1976). "Supersymmetry and spin systems". Journal of Physics A: Mathematical and General. 9 (9): 1497–1506. Bibcode:1976JPhA....9.1497N. doi:10.1088/0305-4470/9/9/010. hdl:11858/00-001M-0000-0013-5EC7-2. S2CID 122243667.
* Nicolai, Hermann (1980). "On a new characterization of scalar supersymmetric theories". Physics Letters B. 89 (3–4): 341–346. Bibcode:1980PhLB...89..341N. doi:10.1016/0370-2693(80)90138-0. hdl:11858/00-001M-0000-0013-5E95-1.
* De Wit, B.; Nicolai, H. (1987). "The consistency of the S$^7$ truncation in d=11 supergravity". Nuclear Physics B. 281 (1–2): 211–240. Bibcode:1987NuPhB.281..211D. doi:10.1016/0550-3213(87)90253-7. hdl:11858/00-001M-0000-0013-5DA7-E.
* De Wit, B.; Hoppe, J.; Nicolai, H. (1988). "On the quantum mechanics of supermembranes". Nuclear Physics B. 305 (4): 545–581. Bibcode:1988NuPhB.305..545D. doi:10.1016/0550-3213(88)90116-2. hdl:11858/00-001M-0000-0013-5D4D-7. (over 950 citation)
* De Wit, B.; Lüscher, M.; Nicolai, H. (1989). "The supermembrane is unstable". Nuclear Physics B. 320 (1): 135–159. Bibcode:1989NuPhB.320..135D. doi:10.1016/0550-3213(89)90214-9. hdl:11858/00-001M-0000-0013-5D23-3.
* Nicolai, H.; Samtleben, H. (2001). "Maximal Gauged Supergravity in Three Dimensions". Physical Review Letters. 86 (9): 1686–1689. arXiv:hep-th/0010076. Bibcode:2001PhRvL..86.1686N. doi:10.1103/PhysRevLett.86.1686. PMID 11290224. S2CID 20407583. arXiv.org
* Damour, T.; Henneaux, M.; Nicolai, H. (2002). "E$_{10}$ and a "Small Tension Expansion" of M Theory". Physical Review Letters. 89 (22): 221601-1–221601-4. arXiv:hep-th/0207267. Bibcode:2002PhRvL..89v1601D. doi:10.1103/PhysRevLett.89.221601. PMID 12485059. S2CID 15550004. arXiv.org
* Damour, T.; Henneaux, M.; Nicolai, H. (2003). "Cosmological billiards". Classical and Quantum Gravity. 20 (9): R145–R200. doi:10.1088/0264-9381/20/9/201. hdl:11858/00-001M-0000-0013-522A-4. S2CID 250877925. arXiv.org
* Nicolai, Hermann; Peeters, Kasper; Zamaklar, Marija (2005). "Loop quantum gravity: An outside view". Classical and Quantum Gravity. 22 (19): R193–R247. doi:10.1088/0264-9381/22/19/R01. hdl:11858/00-001M-0000-0013-4EAC-A. S2CID 14106366. arXiv.org
* Meissner, Krzysztof A.; Nicolai, Hermann (2007). "Conformal symmetry and the Standard Model". Physics Letters B. 648 (4): 312–317. arXiv:hep-th/0612165. Bibcode:2007PhLB..648..312M. doi:10.1016/j.physletb.2007.03.023. S2CID 17973378.
* Damour, Thibault; Nicolai, Hermann (2008). "Symmetries, Singularities and the De-Emergence of Space". International Journal of Modern Physics D. 17 (3n04): 525–531. arXiv:0705.2643. Bibcode:2008IJMPD..17..525D. doi:10.1142/S0218271808012206. S2CID 18836818.
* Bossard, Guillaume; Hillmann, Christian; Nicolai, Hermann (2010). "E$_{7(7)}$ symmetry in perturbatively quantized 𝓝 = 8 supergravity". Journal of High Energy Physics. 2010 (12): 52. arXiv:1007.5472. Bibcode:2010JHEP...12..052B. doi:10.1007/JHEP12(2010)052. S2CID 119241453.
* Nicolai, Hermann; Kleinschmidt, Axel (2010). "E$_{10}$: Eine fundamentale Symmetrie der Physik? Neuer Zugang zur Quantengravitation". Physik in unserer Zeit. 41 (3): 134–140. Bibcode:2010PhuZ...41..134N. doi:10.1002/piuz.201001228. hdl:11858/00-001M-0000-0012-69E6-E. S2CID 209833479.
* Bossard, Guillaume; Nicolai, Hermann (2011). "Counterterms vs. Dualities". Journal of High Energy Physics. 2011 (8): 74. arXiv:1105.1273. Bibcode:2011JHEP...08..074B. doi:10.1007/JHEP08(2011)074. S2CID 119181313.
* Nicolai, Hermann (2014). "Quantum Gravity: The View from Particle Physics". General Relativity, Cosmology and Astrophysics. pp. 369–387. arXiv:1301.5481. doi:10.1007/978-3-319-06349-2_18. ISBN 978-3-319-06348-5. S2CID 117589936. Quantum gravity - the view from particle physics, Prag 2013, arXiv.org