Critical crossover phenomena driven by symmetry-breaking defects at quantum transitions
In: Phys. Rev. E 105, 034139 (2022); (2022)
Online
report
We study the effects of symmetry-breaking defects at continuous quantum transitions (CQTs), which may arise from localized external fields coupled to the order-parameter operator. The problem is addressed within renormalization-group (RG) and finite-size scaling frameworks. We consider the paradigmatic one-dimensional quantum Ising models at their CQT, in the presence of defects which break the global ${\mathbb Z}_2$ symmetry. We show that such defects can give rise to notable critical crossover regimes where the ground-state properties experience substantial and rapid changes, from symmetric conditions to symmetry-breaking boundaries. An effective characterization of these crossover phenomena driven by defects is achieved by analyzing the ground-state fidelity associated with small changes of the defect strength. Within the critical crossover regime, the fidelity susceptibility shows a power-law divergence when increasing the system size, related to the RG dimension of the defect strength; in contrast, outside the critical defect regime, it remains finite. We support the RG scaling arguments with numerical results.
Comment: 13 pages, 11 figures
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Critical crossover phenomena driven by symmetry-breaking defects at quantum transitions
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Autor/in / Beteiligte Person: | Franchi, Alessio ; Rossini, Davide ; Vicari, Ettore |
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Quelle: | Phys. Rev. E 105, 034139 (2022); (2022) |
Veröffentlichung: | 2022 |
Medientyp: | report |
DOI: | 10.1103/PhysRevE.105.034139 |
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