This is a seminar of the string group cross-advertised to our particle group.
Abstract: In the construction of spectral manifolds in noncommutative geometry, a higher degree Heisenberg commutation relation involving the Dirac operator and the Feynman slash of real scalar fields naturally appears and implies, by equality with the index formula, the quantization of the volume. Using the two maps from M_4 to S^4 the four-manifold is built out of a very large number of two kinds of spheres of Planckian volume. The two algebras M_2(H) and M_4(C) are obtained, which are the exact constituents of the standard model. I give several physical applications of this scheme such as quantization of the cosmological constant, mimetic dark matter, and area quantization of black holes.