{"doi":"10.1103/physrevb.104.205112","title":"Fidelity and entanglement entropy for infinite-order phase transitions","abstract":"We study the fidelity and the entanglement entropy for the ground states of quantum systems that have infinite-order quantum phase transitions. In particular, we consider the quantum O(2) model with a spin-$S$ truncation, where there is an infinite-order Gaussian (IOG) transition for $S=1$ and there are Berezinskii-Kosterlitz-Thouless (BKT) transitions for $S\\ensuremath{\\ge}2$. We show that the height of the peak in the fidelity susceptibility (${\\ensuremath{\\chi}}_{F}$) converges to a finite thermodynamic value as a power law of $1/L$ for the IOG transition and as $1/ln(L)$ for BKT transitions. The peak position of ${\\ensuremath{\\chi}}_{F}$ resides inside the gapped phase for both the IOG transition and BKT transitions. On the other hand, the derivative of the block entanglement entropy with respect to the coupling constant (${S}_{vN}^{\\ensuremath{'}}$) has a peak height that diverges as ${ln}^{2}(L)$ for $S=1$ and ${ln}^{3}(L)$ for $S\\ensuremath{\\ge}2$ and can be used to locate both kinds of transitions accurately. We include higher-order corrections for finite-size scalings and obtain the value of the central charge consistent with $c=1$ predicted by conformal field theory. The crossing point of ${\\ensuremath{\\chi}}_{F}$ between different system sizes is at the IOG point for $S=1$ but is inside the gapped phase for $S\\ensuremath{\\ge}2$, while those of ${S}_{vN}^{\\ensuremath{'}}$ are at the phase-transition points for all $S$ truncations. Our work elaborates on how to use the finite-size scaling of ${\\ensuremath{\\chi}}_{F}$ or ${S}_{vN}^{\\ensuremath{'}}$ to detect infinite-order quantum phase transitions and discusses the efficiency and accuracy of the two methods.","journal":"Physical review. B./Physical review. B","year":2021,"id":226214,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9535,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":829224,"name":"Jin Zhang","orcid":"0000-0003-0568-4221","position":0,"is_corresponding":true}],"reference_count":75,"raw_metadata":null,"created_at":"2026-07-18T23:54:34.185847Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}