Symmetry, Integrability and Geometry: Methods and Applications (SIGMA)


SIGMA 21 (2025), 081, 61 pages      arXiv:2409.11306      https://doi.org/10.3842/SIGMA.2025.081

Killing (Super)Algebras Associated to Connections on Spinors

Andrew D.K. Beckett
University of Edinburgh, UK

Received November 28, 2024, in final form September 15, 2025; Published online September 30, 2025

Abstract
We generalise the notion of a Killing superalgebra, which arises in the physics literature on supergravity, to general dimension, signature and choice of spinor module and Dirac current. We also allow for Lie algebras as well as superalgebras, capturing a set of examples previously defined using geometric Killing spinors on higher-dimensional spheres. Our definition requires a connection on a spinor bundle - provided by supersymmetry transformations in the supergravity examples and by the Killing spinor equation on the spheres - and we obtain a set of sufficient conditions on such a connection for the Killing (super)algebra to exist. We show that these Lie (super)algebras are filtered deformations of graded subalgebras of (a generalisation of) the Poincaré superalgebra and then study such deformations abstractly using Spencer cohomology. In the highly supersymmetric Lorentzian case, we describe the filtered subdeformations which are of the appropriate form to arise as Killing superalgebras, lay out a classification scheme for their odd-generated subalgebras and prove that, under certain technical conditions, there exist homogeneous Lorentzian spin manifolds on which these deformations are realised as Killing superalgebras. Our results generalise previous work in the 11-dimensional supergravity literature.

Key words: Lie superalgebra; Killing superalgebra; Killing spinor; connection; superconnection; isometry; Spencer cohomology; filtration; deformation; homogeneous.

pdf (918 kb)   tex (85 kb)  

References

  1. Alekseevsky D.V., Chrysikos I., Spin structures on compact homogeneous pseudo-Riemannian manifolds, Transform. Groups 24 (2019), 659-689, arXiv:1602.07968.
  2. Alekseevsky D.V., Cortés V., Classification of $N$-(super)-extended Poincaré algebras and bilinear invariants of the spinor representation of ${\rm Spin}(p,q)$, Comm. Math. Phys. 183 (1997), 477-510, arXiv:math.RT/9511215.
  3. Alekseevsky D.V., Cortés V., Devchand C., Semmelmann U., Killing spinors are Killing vector fields in Riemannian supergeometry, J. Geom. Phys. 26 (1998), 37-50, arXiv:dg-ga/9704002.
  4. Alekseevsky D.V., Cortés V., Devchand C., Van Proeyen A., Polyvector super-Poincaré algebras, Comm. Math. Phys. 253 (2005), 385-422, arXiv:hep-th/0311107.
  5. Bär C., The Dirac operator on homogeneous spaces and its spectrum on $3$-dimensional lens spaces, Arch. Math. (Basel) 59 (1992), 65-79.
  6. Bär C., Gauduchon P., Moroianu A., Generalized cylinders in semi-Riemannian and Spin geometry, Math. Z. 249 (2005), 545-580, arXiv:math.DG/0303095.
  7. Beckett A., Generalised spencer cohomology and 5-dimensional supersymmetry, Master Thesis, University of Edinburgh, 2019, https://www.maths.ed.ac.uk/ jmf/SRG/papers/ABDiss.pdf.
  8. Beckett A., Spencer cohomology, supersymmetry and the structure of Killing superalgebras, Ph.D. Thesis, University of Edinburgh, 2024, https://doi.org/10.7488/era/4477.
  9. Beckett A., Killing superalgebras in 2 dimensions, SIGMA 21 (2025), 082, 16 pages, arXiv:2410.01765.
  10. Beckett A., Figueroa-O'Farrill J., Killing superalgebras for lorentzian five-manifolds, J. High Energy Phys. 2021 (2021), no. 7, 209, 40 pages, arXiv:2105.05775.
  11. Bohle C., Killing spinors on Lorentzian manifolds, J. Geom. Phys. 45 (2003), 285-308.
  12. Bott R., The index theorem for homogeneous differential operators, in Differential and Combinatorial Topology (A Symposium in Honor of Marston Morse), Princeton University Press, Princeton, NJ, 1965, 167-186.
  13. Cahen M., Gutt S., Trautman A., Spin structures on real projective quadrics, J. Geom. Phys. 10 (1993), 127-154.
  14. Čap A., Neusser K., On automorphism groups of some types of generic distributions, Differential Geom. Appl. 27 (2009), 769-779, arXiv:0807.0974.
  15. Čap A., Slov'ak J., Parabolic geometries. I. Background and general theory, Math. Surveys Monogr., Vol. 154, American Mathematical Society, Providence, RI, 2009.
  16. Cheng S.J., Kac V.G., Generalized Spencer cohomology and filtered deformations of ${\bf Z}$-graded Lie superalgebras, Adv. Theor. Math. Phys. 2 (1998), 1141-1182, Addendum, Adv. Theor. Math. Phys. 8 (2004), 697-709, arXiv:math.RT/9805039.
  17. Cortés V., Gall L., Mohaupt T., Four-dimensional vector multiplets in arbitrary signature (I), Int. J. Geom. Methods Mod. Phys. 17 (2020), 2050150, 25 pages, arXiv:1907.12067.
  18. Cortés V., Lazaroiu C., Shahbazi C.S., Spinors of real type as polyforms and the generalized Killing equation, Math. Z. 299 (2021), 1351-1419, arXiv:1911.08658.
  19. D'Auria R., Ferrara S., Lledó M.A., Varadarajan V.S., Spinor algebras, J. Geom. Phys. 40 (2001), 101-129, arXiv:hep-th/0010124.
  20. D'Auria R., Fré P., Geometric supergravity in $D=11$ and its hidden supergroup, Nuclear Phys. B 201 (1982), 101-140, Erratum, Nuclear Phys. B 206 (1982), 496-496.
  21. D'Auria R., Fré P., Regge T., Graded-Lie-algebra cohomology and supergravity, Riv. Nuovo Cimento (3) 3 (1980), 37.
  22. de Medeiros P., Figueroa-O'Farrill J., Santi A., Killing superalgebras for Lorentzian four-manifolds, J. High Energy Phys. 2016 (2016), no. 6, 106, 49 pages, arXiv:1605.00881.
  23. de Medeiros P., Figueroa-O'Farrill J., Santi A., Killing superalgebras for lorentzian six-manifolds, J. Geom. Phys. 132 (2018), 13-44, arXiv:1804.00319.
  24. Figueroa-O'Farrill J., A geometric construction of the exceptional Lie algebras $F_4$ and $E_8$, Comm. Math. Phys. 283 (2008), 663-674, arXiv:0706.2829.
  25. Figueroa-O'Farrill J., Spin geometry, 2017, https://empg.maths.ed.ac.uk/Activities/Spin/SpinNotes.pdf.
  26. Figueroa-O'Farrill J., Hackett-Jones E., Moutsopoulos G., The Killing superalgebra of 10-dimensional supergravity backgrounds, Classical Quantum Gravity 24 (2007), 3291-3308, arXiv:hep-th/0703192.
  27. Figueroa-O'Farrill J., Hackett-Jones E., Moutsopoulos G., Simón J., On the maximal superalgebras of supersymmetric backgrounds, Classical Quantum Gravity 26 (2009), 035016, 17 pages, arXiv:0809.5034.
  28. Figueroa-O'Farrill J., Hustler N., The homogeneity theorem for supergravity backgrounds, J. High Energy Phys. 2012 (2012), no. 10, 014, 8 pages, arXiv:1208.0553.
  29. Figueroa-O'Farrill J., Hustler N., The homogeneity theorem for supergravity backgrounds II: the six-dimensional theories, J. High Energy Phys. 2014 (2014), no. 4, 131, 16 pages, arXiv:1312.7509.
  30. Figueroa-O'Farrill J., Meessen P., Philip S., Supersymmetry and homogeneity of M-theory backgrounds, Classical Quantum Gravity 22 (2005), 207-226, arXiv:hep-th/0409170.
  31. Figueroa-O'Farrill J., Santi A., Eleven-dimensional supergravity from filtered subdeformations of the Poincaré superalgebra, J. Phys. A 49 (2016), 295204, 7 pages, arXiv:1511.09264.
  32. Figueroa-O'Farrill J., Santi A., On the algebraic structure of Killing superalgebras, Adv. Theor. Math. Phys. 21 (2017), 1115-1160, arXiv:1608.05915.
  33. Figueroa-O'Farrill J., Santi A., Spencer cohomology and 11-dimensional supergravity, Comm. Math. Phys. 349 (2017), 627-660, arXiv:1511.08737.
  34. Fiorenza D., Sati H., Schreiber U., Super-Lie $n$-algebra extensions, higher WZW models and super-$p$-branes with tensor multiplet fields, Int. J. Geom. Methods Mod. Phys. 12 (2015), 1550018, 35 pages, arXiv:1308.5264.
  35. Gall L., Mohaupt T., Supersymmetry algebras in arbitrary signature and their R-symmetry groups, J. High Energy Phys. 2021 (2021), no. 10, 203, 86 pages, arXiv:2108.05109.
  36. Gauntlett J.P., Pakis S., The geometry of $D=11$ Killing spinors, J. High Energy Phys. 2003 (2003), no. 4, 039, 33 pages, arXiv:hep-th/0212008.
  37. Geroch R., Limits of spacetimes, Comm. Math. Phys. 13 (1969), 180-193.
  38. Gil-García A., Shahbazi C.S., Parallel spinors for ${\rm G}_2^*$ and isotropic structures, Ann. Global Anal. Geom. 67 (2025), 9, 23 pages, arXiv:2409.08553.
  39. Gran U., Gutowski J., Papadopoulos G., Classification, geometry and applications of supersymmetric backgrounds, Phys. Rep. 794 (2019), 1-87, arXiv:1808.07879.
  40. Habib G., Roth J., Skew Killing spinors, Cent. Eur. J. Math. 10 (2012), 844-856, arXiv:1110.2061.
  41. Harvey F.R., Spinors and calibrations, Perspect. Math., Vol. 9, Academic Press, Inc., Boston, MA, 1990.
  42. Hustler N., Homogeneity in Supergravity, Ph.D. Thesis, University of Edinburgh, 2016, http://hdl.handle.net/1842/19576.
  43. Kac V.G., Lie superalgebras, Adv. Math. 26 (1977), 8-96.
  44. Kobayashi S., Nomizu K., Foundations of differential geometry. Vol. II, Intersci. Tracts Pure Appl. Math., Vol. 15, Interscience Publishers John Wiley & Sons, Inc., New York, 1969.
  45. Kosmann Y., Dérivées de Lie des spineurs, Ann. Mat. Pura Appl. 91 (1972), 317-395.
  46. Kostant B., Holonomy and the Lie algebra of infinitesimal motions of a Riemannian manifold, Trans. Amer. Math. Soc. 80 (1955), 528-542.
  47. Lawson Jr. H.B., Michelsohn M.L., Spin geometry, Princeton Math. Ser., Vol. 38, Princeton University Press, Princeton, NJ, 1989.
  48. Lazaroiu C.I., Babalic E.-M., Geometric algebra techniques in flux compactifications, Adv. High Energy Phys. 2016 (2016), 7292534, 42 pages, arXiv:1212.6766.
  49. Lazaroiu C.I., Shahbazi C.S., On the spin geometry of supergravity and string theory, in Geometric Methods in Physics XXXVI, Trends Math., Birkhäuser, Cham, 2019, 229-235, arXiv:1607.02103.
  50. Lazaroiu C.I., Shahbazi C.S., Real pinor bundles and real Lipschitz structures, Asian J. Math. 23 (2019), 749-836, arXiv:1606.07894.
  51. Lichnerowicz A., Spin manifolds, Killing spinors and universality of the Hijazi inequality, Lett. Math. Phys. 13 (1987), 331-344.
  52. Moroianu A., Parallel and Killing spinors on ${\rm Spin}^c$ manifolds, Comm. Math. Phys. 187 (1997), 417-427.
  53. Moroianu A., Semmelmann U., Generalized Killing spinors on Einstein manifolds, Internat. J. Math. 25 (2014), 1450033, 19 pages, arXiv:1303.6179.
  54. Nomizu K., Invariant affine connections on homogeneous spaces, Amer. J. Math. 76 (1954), 33-65.
  55. Santi A., Superization of homogeneous spin manifolds and geometry of homogeneous supermanifolds, Abh. Math. Semin. Univ. Hambg. 80 (2010), 87-144, arXiv:0905.3832.
  56. Santi A., Remarks on highly supersymmetric backgrounds of 11-dimensional supergravity, in Geometry, Lie Theory and Applications - the Abel Symposium 2019, Abel Symp., Vol. 16, Springer, Cham, 2022, 253-277, arXiv:1912.10688.
  57. Sati H., Schreiber U., Stasheff J., $L_\infty$-algebra connections and applications to String- and Chern-Simons $n$-transport, in Quantum Field Theory, Birkhäuser, Basel, 2009, 303-424, arXiv:0801.3480.
  58. Scheunert M., The theory of Lie superalgebras: an introduction, Lecture Notes in Math., Vol. 716, Springer, Berlin, 1979.
  59. Shahbazi C.S., Differential spinors and Kundt three-manifolds with skew-torsion, arXiv:2405.03756.
  60. Sharpe R.W., Differential geometry. Cartan's generalization of Klein's Erlangen program, Grad. Texts in Math., Vol. 166, Springer, New York, 1997.
  61. Stasheff J., $L_\infty$ and $A_\infty$ structures: then and now, arXiv:1809.02526.
  62. Stehney A.K., Millman R.S., Riemannian manifolds with many Killing vector fields, Fund. Math. 105 (1980), 241-247.
  63. Strathdee J., Extended Poincaré supersymmetry, Internat. J. Modern Phys. A 2 (1987), 273-300.
  64. The Stacks Project Authors, The Stacks project, 2023, https://stacks.math.columbia.edu.
  65. Van Proeyen A., Tools for supersymmetry, Ann. Univ. Craiova Phys. 9 (1999), 1-48, arXiv:hep-th/9910030.
  66. Wang H.-C., On invariant connections over a principal fibre bundle, Nagoya Math. J. 13 (1958), 1-19.
  67. Wise D.K., MacDowell-Mansouri gravity and Cartan geometry, Classical Quantum Gravity 27 (2010), 155010, 26 pages, arXiv:gr-qc/0611154.

Previous article  Next article  Contents of Volume 21 (2025)