The chemistry community has long sought the exact relationship between conventional and unitary coupled cluster ansatz for a single-reference system, especially given interest in performing quantum on computers. In this work, we show how one can use operator manipulations by exponential disentangling identity Hadamard lemma to relate factorized form of coupled-cluster approximation (the is requ...

We formulate a general theory of the strong coupling limit of renormalizable interacting quantum fields. For definiteness, our ideas are explicitly illustrated in the case of the scalar field with quartic self-coupling, the usual testing ground for new ideas in field theory. More precisely, the generating functional for connected Green's functions is explicitly constructed for this latter theor...