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Title: Do dynamical quantum phase transitions survive at finite temperature
Plain: The theory is built for pure starting states at zero temperature. For warm starting states several competing definitions exist, and they disagree on whether the sharp kinks remain.
Precise: For an initial Gibbs state $\rho_0 = \exp(-\beta H_i)/Z$, compare generalized Loschmidt echoes (the interferometric echo $\operatorname{tr}(\rho_0 U(t))$ and fidelity-based echoes) in interacting models. Does any measurable generalization show nonanalyticities at finite $\beta$ that connect continuously to the pure-state transitions as $\beta \to \infty$? Answer yes or no, with the definition.
Settled by: Exact free-fermion results extended to interacting chains by numerics, together with a measurement protocol.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: open
Status note: (empty)
Posed since: (empty)