Thouless pumping and generation of squeezed Fock-state superpositions in a Fock-state lattice

Abstract

In this paper, Thouless pumping in a one-dimensional semi-infinite Fock-state lattice is investigated. A distinctive feature of such lattices is the intrinsic $\sqrt{n}$-dependent coupling arising from the bosonic mode, which leads to spatially nonuniform hopping amplitudes. In the dimer limit, the topological invariants and the quantized transport dynamics in the Fock-state basis are numerically evaluated and analyzed. By introducing an additional inter-cell coupling and applying a squeezing transformation, the framework is then extended to Thouless pumping in the squeezed Fock-state basis, where a topologically protected scheme for preparing superpositions of squeezed Fock states is proposed. This study establishes Thouless pumping in Fock-state lattices as a useful tool for quantum state engineering, shifting the focus from observing topological transport to harnessing it for the preparation of non-classical states of the bosonic mode.