What's new inTGD: Physics as InfiniteDimensional GeometryNote: Newest contributions are at the top! 
Year 2008 
How quantum classical correspondence is realized at parton level?Quantum classical correspondence must assign to a given quantum state the most probable spacetime sheet depending on its quantum numbers. The spacetime sheet X^{4}(X^{3}) defined by the Kähler function depends however only on the partonic 3surface X^{3}, and one must be able to assign to a given quantum state the most probable X^{3}  call it X^{3}_{max}  depending on its quantum numbers. X^{4}(X^{3}_{max}) should carry the gauge fields created by classical gauge charges associated with the Cartan algebra of the gauge group (color isospin and hypercharge and electromagnetic and Z^{0} charge) as well as classical gravitational fields created by the partons. This picture is very similar to that of quantum field theories relying on path integral except that the path integral is restricted to 3surfaces X^{3} with exponent of Kähler function bringing in genuine convergence and that 4D dynamics is deterministic apart from the delicacies due to the 4D spin glass type vacuum degeneracy of Kähler action. Stationary phase approximation selects X^{3}_{max} if the quantum state contains a phase factor depending not only on X^{3} but also on the quantum numbers of the state. A good guess is that the needed phase factor corresponds to either ChernSimons type action or a boundary term of YM action associated with a particle carrying gauge charges of the quantum state. This action would be defined for the induced gauge fields. YM action seems to be excluded since it is singular for lightlike 3surfaces associated with the lightlike wormhole throats (not only (det(g_{3})^{1/2} but also det(g_{4})^{1/2} vanishes). The challenge is to show that this is enough to guarantee that X^{4}(X^{3}_{max}) carries correct gauge charges. Kind of electricmagnetic duality should relate the normal components F_{ni} of the gauge fields in X^{4}(X^{3}_{max}) to the gauge fields F_{ij} induced at X^{3}. An alternative interpretation is in terms of quantum gravitational holography. The difference between ChernSimons action characterizing quantum state and the fundamental ChernSimons type factor associated with the Kähler form would be that the latter emerges as the phase of the Dirac determinant. One is forced to introduce gauge couplings and also electroweak symmetry breaking via the phase factor. This is in apparent conflict with the idea that all couplings are predictable. The essential uniqueness of Mmatrix in the case of HFFs of type II_{1} (at least) however means that their values as a function of measurement resolution time scale are fixed by internal consistency. Also quantum criticality leads to the same conclusion. Obviously a kind of bootstrap approach suggests itself. For background see the chapter Configuration space spinor structure. 
How padic coupling constant evolution and padic length scale hypothesis emerge from quantum TGD proper?What padic coupling constant evolution really means has remained for a long time more or less open. The progress made in the understanding of the Smatrix of theory has however changed the situation dramatically. 1. Mmatrix and coupling constant evolution The final breakthrough in the understanding of padic coupling constant evolution came through the understanding of Smatrix, or actually Mmatrix defining entanglement coefficients between positive and negative energy parts of zero energy states in zero energy ontology (see this). Mmatrix has interpretation as a "complex square root" of density matrix and thus provides a unification of thermodynamics and quantum theory. Smatrix is analogous to the phase of Schrödinger amplitude multiplying positive and real square root of density matrix analogous to modulus of Schrödinger amplitude. The notion of finite measurement resolution realized in terms of inclusions of von Neumann algebras allows to demonstrate that the irreducible components of Mmatrix are unique and possesses huge symmetries in the sense that the hermitian elements of included factor N subset M defining the measurement resolution act as symmetries of Mmatrix, which suggests a connection with integrable quantum field theories. It is also possible to understand coupling constant evolution as a discretized evolution associated with time scales T_{n}, which come as octaves of a fundamental time scale: T_{n}=2^{n}T_{0}. Number theoretic universality requires that renormalized coupling constants are rational or at most algebraic numbers and this is achieved by this discretization since the logarithms of discretized mass scale appearing in the expressions of renormalized coupling constants reduce to the form log(2^{n})=nlog(2) and with a proper choice of the coefficient of logarithm log(2) dependence disappears so that rational number results. 2. pAdic coupling constant evolution One can wonder how this picture relates to the earlier hypothesis that padic length coupling constant evolution is coded to the hypothesized log(p) normalization of the eigenvalues of the modified Dirac operator D. There are objections against this normalization. log(p) factors are not number theoretically favored and one could consider also other dependencies on p. Since the eigenvalue spectrum of D corresponds to the values of Higgs expectation at points of partonic 2surface defining number theoretic braids, Higgs expectation would have log(p) multiplicative dependence on padic length scale, which does not look attractive. Is there really any need to assume this kind of normalization? Could the coupling constant evolution in powers of 2 implying time scale hierarchy T_{n}= 2^{n}T_{0} induce padic coupling constant evolution and explain why padic length scales correspond to L_{p} propto p^{1/2}R, p≈ 2^{k}, R CP_{2} length scale? This looks attractive but there is a problem. pAdic length scales come as powers of 2^{1/2} rather than 2 and the strongly favored values of k are primes and thus odd so that n=k/2 would be half odd integer. This problem can be solved.
