Soft modes, resulting nonanalyticities occur in an entire phase

These are generic soft modes


How big a deal? (After all, these are just standard corrections to scaling!)




II. Interplay with Quantum Critical Behavior


Critical fixed point Phase transition driven by critical soft modes
(OP fluctuations)


Coupling between generic soft modes and OP fluctuations


This can happen at classical transitions, too (e.g., compressible magnets), but


Examples: Various magnetic QPTs in metals