Pseudo-critical phenomena in first-order phase transitions

H. Ikeda

Progress of Theoretical Physics Vol. 61 No. 4 (1979) pp. 1023-1033:Pseudo-Critical Dynamics in First-Order Transitions Hiroshi Ikeda Progress of Theoretical Physics Vol. 63 No. 1 (1980) pp. 42-50:Pseudo-Critical Phenomena in the Fisher-Domb Cluster Model Hiroshi Ikeda

V. Rizi, S. K. Ghosh

Manuel Weber

Emergent symmetries and slow crossover phenomena are central themes in quantum criticality and manifest themselves in the pseudocritical scaling experienced in the context of deconfined criticality. Here we discover its conceptual counterpart, i.e., a symmetry-enhanced pseudo-first-order transition. It emerges from a one-dimensional realization of deconfined criticality between charge- and bond-ordered states driven by competing Holstein and Su-Schrieffer-Heeger electron-phonon couplings, for which quantum fluctuations and thereby the nature of the transition can be tuned systematically via the phonon frequency $ω_0$. In the classical limit $ω_0 \to 0$, a low-energy Dirac theory predicts a direct first-order transition with emergent U(1) symmetry. Using exact quantum Monte Carlo simulations, we provide strong evidence for symmetry enhancement and even finite-size scaling on intermediate length scales but in the thermodynamic limit it turns into a narrow intermediate phase where both order parameters are finite, as chiral U(1) symmetry is weakly broken on the lattice. Including quantum lattice fluctuations diminishes the width of the intermediate phase, gradually restores the U(1) symmetry, and eventually tunes the system to a deconfined quantum critical point.

Per-Anker Lindgård

H. Ikeda