Hardness of observing strong-to-weak symmetry breaking
8 days ago
- #Symmetry Breaking
- #Quantum Physics
- #Open Quantum Systems
- Spontaneous symmetry breaking (SSB) is fundamental in understanding quantum phases of matter.
- Recent works extend SSB to mixed states in open quantum systems, introducing strong and weak symmetry realizations.
- Novel mixed phases of quantum matter can be defined by the breaking of strong symmetry down to weak symmetry.
- Proposed order parameters for strong-to-weak SSB require exponentially many copies of the state, raising efficiency concerns.
- The study concludes that efficient detection of strong-to-weak SSB is not possible in general for $Z_2$ and $U(1)$ symmetries.
- Pseudorandom mixed states are constructed that mimic symmetry-breaking states, making them computationally indistinguishable.