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Recently, one-dimensional topological p-wave superconductors have attracted significant interest in the realm of topological quantum computing. Typically, these systems involve proximity-induced superconductivity. However, it is intriguing to explore one-dimensional fermionic systems that conserve charge and are thus inherently gapless. In our study, we begin by examining an isotropic Hamiltonian that describes spinful fermions on a 1D chain to investigate emergent superconductivity. Through large-scale infinite density matrix renormalization group (iDMRG) simulations, we identify two distinct phases: a weak coupling phase with gapless fermion excitations and a strong coupling phase marked by gapless 4e boson excitations. We find that the correlation functions can be accurately described by a simple two-fluid model. Furthermore, introducing an easy-axis anisotropic interaction reveals a new pattern: a gapless symmetry-protected state emerges in the weak coupling phase, while 2e superconductivity becomes possible in the strong coupling phase.

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Jiaxin Qiao, TU Munich
Seminar Room 0.03, ETP
Contact: Simon Trebst