Abstract
We study the sub-Laplacian of the 15-dimensional unit sphere which is obtained by lifting with respect to the Hopf fibration the Laplacian of the octonionic projective space. We obtain in particular explicit formulas for its heat kernel and deduce an expression for the Green function of a related sub-Laplacian. As a byproduct we also obtain the spectrum of the sub-Laplacian, the small-time asymptotics of the heat kernel and explicitly compute the sub-Riemannian distance.
Similar content being viewed by others
References
Baudoin, F.: Sub-Laplacians and hypoelliptic operators on totally geodesic Riemannian foliations. Geometry, analysis and dynamics on sub-Riemannian manifolds 1, 259–321 (2016). MR3587668
Baudoin, F., Bonnefont, M.: The subelliptic heat kernel on SU(2): representations, asymptotics and gradient bounds. Math. Z. 263(3), 647–672 (2009). https://doi.org/10.1007/s00209-008-0436-0. MR2545862
Baudoin, F., Grong, E., Molino, G., Rizzi, L.: H-type foliations (2018)
Baudoin, F., Wang, J.: The subelliptic heat kernel on the CR sphere. Math. Z. 275(1-2), 135–150 (2013). https://doi.org/10.1007/s00209-012-1127-4. MR3101801
Baudoin, F., Wang, J.: The subelliptic heat kernels of the quaternionic Hopf fibration. Potential Anal. 41(3), 959–982 (2014). https://doi.org/10.1007/s11118-014-9403-z. MR3264830
Baudoin, F., Wang, J.: Stochastic areas, winding numbers and Hopf fibrations. Probab. Theory Related Fields 169(3-4), 977–1005 (2017). https://doi.org/10.1007/s00440-016-0745-x. MR3719061
Beals, R., Gaveau, B., Greiner, P.C.: Hamilton-Jacobi theory and the heat kernel on Heisenberg groups. J. Math. Pures Appl. (9) 79(7), 633–689 (2000). MR1776501
Bérard-Bergery, L., Bourguignon, J.-P.: Laplacians and Riemannian submersions with totally geodesic fibres. Illinois J. Math. 26(2), 181–200 (1982). MR650387
Besse, A.L.: Manifolds all of whose geodesics are closed. Ergebnisse der Mathematik und ihrer Grenzgebiete [Results in Mathematics and Related Areas], vol. 93. Springer-Verlag, Berlin-New York (1978). With appendices by D. B. A. Epstein, J.-P. Bourguignon, L. Bérard-Bergery, M. Berger and J. L. Kazdan. MR496885
Besse, A.L.: Einstein manifolds. Ergebnisse der Mathematik und ihrer Grenzgebiete (3) [Results in Mathematics and Related Areas (3)], vol. 10. Springer-Verlag, Berlin (1987). MR867684
Demni, N., Zani, M.: Large deviations for statistics of the Jacobi process. Stochastic Process. Appl. 119(2), 518–533 (2009). https://doi.org/10.1016/j.spa.2008.02.015. MR2494002
Escobales, R., Jr.: Riemannian submersions with totally geodesic fibers. J. Differential Geometry 10, 253–276 (1975). https://doi.org/http://projecteuclid.org/euclid.jdg/1214432793. MR370423
Escobales, R.H., Jr.: Riemannian foliations of the rank one symmetric spaces. Proc. Amer. Math. Soc. 95(3), 495–498 (1985). MR806095
Faraut, J.: Analysis on Lie groups. Cambridge Studies in Advanced Mathematics, vol. 110. Cambridge University Press, Cambridge (2008). An introduction. MR2426516
Geller, D.: The Laplacian and the Kohn Laplacian for the sphere. J. Differential Geometry 15(3), 417–435 (1981) (1980). MR620896
Greiner, P.C.: A Hamiltonian approach to the heat kernel of a sublaplacian on S2n+ 1. Anal. Appl. (Singap.) 11(6), 1350035 (2013). https://doi.org/10.1142/S0219530513500358. 62 MR3130140
Helgason, S.: The Radon transform on Euclidean spaces, compact two-point homogeneous spaces and Grassmann manifolds. Acta Math. 113, 153–180 (1965). https://doi.org/10.1007/BF02391776. MR172311
Helgason, S.: Groups and geometric analysis. Pure and Applied Mathematics, vol. 113. Academic Press, Inc., Orlando, FL (1984). Integral geometry, invariant differential operators, and spherical functions. MR754767
Léandre, R.: Majoration en temps petit de la densité d’une diffusion dégénérée. Probab. Theory Related Fields 74(2), 289–294 (1987). MR871256
Léandre, R.: Minoration en temps petit de la densité d’une diffusion dégénérée. J. Funct. Anal. 74(2), 399–414 (1987). MR904825
Ornea, L., Parton, M., Piccinni, P., Vuletescu, V.: Spin(9) geometry of the octonionic Hopf fibration. Transform. Groups 18(3), 845–864 (2013). https://doi.org/10.1007/s00031-013-9233-x. MR3084336
Ranjan, A.: Riemannian submersions of spheres with totally geodesic fibres. Osaka J. Math. 22(2), 243–260 (1985). http://projecteuclid.org/euclid.ojm/1200778256 MR800969
Ucci, J.: On the nonexistence of Riemannian submersions from C P(7) and QP(3). Proc. Amer. Math. Soc. 88(4), 698–700 (1983). https://doi.org/10.2307/2045465. MR702302
Wang, J.: Conformal transforms and Doob’s h-processes on Heisenberg groups, Stochastic analysis and related topics, pp. 165–177. MR3737629 (2017)
Acknowledgments
The authors thank the anonymous referee for a careful reading and remarks that greatly helped improve the presentation of the paper. We point out that due to their complexity, some of the symbolic computations were computer assisted using the software Mathematica.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
F.B is partially funded by the Simons Foundation and NSF grant DMS-1901315.
Rights and permissions
About this article
Cite this article
Baudoin, F., Cho, G. The Subelliptic Heat Kernel of the Octonionic Hopf Fibration. Potential Anal 55, 211–228 (2021). https://doi.org/10.1007/s11118-020-09854-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11118-020-09854-4