Many-body theory of false vacuum decay in quantum spin chains

In this work, we theoretically investigate the false vacuum decay process in a ferromagnetic quantum spin-1/2 chain. We develop a many-body theory describing the nucleation and the coherent dynamics of true-vacuum bubbles that is analytically tractable and agrees with numerical matrix product state calculations in all parameter regimes up to intermediate times. This theory allows us to identify different regimes in the parameter space and unravel the underlying physical mechanisms, thus offering conceptual insight into the microscopic quantum dynamics of metastable states. In particular, analogies and differences with the cosmological false vacuum decay picture are highlighted and characterized in terms of experimentally observable quantities.