Dissipation-driven first-order phase transition in superconductors

The interplay between superconductivity and environmental dissipation opens a new frontier for exotic quantum phases. We investigate how dissipation can fundamentally alter the nature of the superconducting phase transition. Utilizing a right-eigenstate-based non-Hermitian mean-field theory, essential for ensuring physically meaningful predictions in interacting open systems, we uncover a novel mechanism where dissipation drives a first-order phase transition in an s-wave superconductor. This transition originates from the abrupt topological reconstruction of the energy spectrum associated with \({\cal P}{\cal T}\)-symmetry breaking, thereby coinciding exactly with the \({\cal P}{\cal T}\)-symmetry breaking point. Remarkably, and contrary to conventional wisdom, we find that moderate dissipation enhances superconductivity by increasing the density of states, whereas stronger dissipation causes its abrupt suppression. These phenomena, characterized by discontinuous jumps in observables such as superfluid density, are readily accessible in experimental platforms like ultracold atoms with engineered dissipation. Our findings establish environmental coupling as a new pathway to control the order of quantum phase transitions.