Suppose I have the vacuum state |0> without loss of generality for quantum electrodynamics (with topological term proportional to EB) with the following additional feature:
The Hamiltonian H(t)=Hmatter(t)+∫Md3x(12(E2+B2)+θEB) is defined only within the region M⊂R3 and on the N covering sets Gi⊂R3−M,i∈{1,…,N} this operator does not exist. Therefore, H must act on states |0,G1,…,GN;t> which have these covering sets as an additional degree of freedom that form an orthogonal basis in Hilbert space; an inner product is one if the product is formed between two equal states and 0 otherwise.
Now one can try to construct the path integral; the derivation of the path integral for quantum electrodynamics is straightforward, but one encounters with inner products <0,G′1,…,G′N;t+dt|0,G1,…,GN;t>. The inner product should be defined such that the set of all space topologies is generalized to spacetime topologies. For simplicity one can say that this inner product is a constant a (can be determined by normalization) if there exist morphisms M(Gi,G′j) that lie on intersections Gi∩G′j (because one can define a functor from intersections in category of sets to chart transition morphisms in category of manifolds) for all i∈{1,…,N} while G′j is in 4-dimensional neighorhood of Gi and zero otherwise. Finally, (normalization factor a can be absorbed into the integral measure) one would obtain the generalized path integral:
Z=∫D[G∗i(tn)]…∫D[Gi(t1)]∫D[Aμ]∫D[ψ]eiSQED1Consistency
Here, 1Consistency is the indicator function that satisfies above consistency conditions.
Questions:
- Does a theory like this exist in research literature?
- Makes such a theory, a sum over topologies, sense?
- Can the "sum over topologies" also be defined on algebraic varieties or other topological spaces?