  We examine the condensation and confinement mechanisms exhibited by a
deformed toric code model proposed in [Castelnovo and Chamon, Phys. Rev. B,
2008]. The model describes both sides of a phase transition from a topological
phase to a trivial phase. Our findings reveal an unconventional confinement
mechanism that governs the behavior of the toric code excitations within the
trivial phase. Specifically, the confined magnetic charge can still be
displaced without any energy cost, albeit only via the application of
non-unitary operators that reduce the norm of the state. This peculiar
phenomenon can be attributed to a previously known feature of the model: it
maintains the non-trivial ground state degeneracy of the toric code throughout
the transition. We describe how this degeneracy arises in both phases in terms
of spontaneous symmetry breaking of a generalized (1-form) symmetry and explain
why such symmetry breaking is compatible with the trivial phase. The present
study implies the existence of subtle considerations that must be addressed in
the context of recently posited connections between topological phases and
broken higher-form symmetries.
