The thermodynamic arrow of time + the Second law of thermodynamics are thought to be a consequence of the initial conditions in the early universe. Not possible to ‘rewind’... but to be fair, this is supposed not to be a problem for [any] T-symmetry, because there are no proofs T-symmetry must be broken also at the microscopic level.I am not sure what you mean. How do you check whether expansion is time-symmetric? How does it connect to the FW theory?
How this would play out in the ‘real world’, I have absolutely no clue...
Feynman, R. P., 1949, Physical Review 76, 769 (1949)Can you give a reference? People often state many things without convincing arguments.
Sorry to be a ‘party pooper’, but if the [extremely intelligent] author of an idea gives up on it – what have you then...?Space-Time Approach to Quantum Electrodynamics said:3. THE SELF-ENERGY PROBLEM
Having a term representing the mutual interaction of a pair of charges, we must include similar terms to represent the interaction of a charge with itself. For under some circumstances what appears to be two distinct electrons may, according to I, be viewed also as a single electron (namely in case one electron was created in a pair with a positron destined to annihilate the other electron). Thus to the interaction between such electrons must correspond the possibility of the action of an electron on itself.9
9 These considerations make it appear unlikely that the contention of J.A. Wheeler and R.P. Feynman, Rev. Mod. Phys. 17, 157 (1945), that electrons do not act on themselves, will be a successful concept in quantum electrodynamics.