[{"issue":"4","das_tickbox":"1","main_file_link":[{"open_access":"1","url":"https://doi.org/10.48550/arXiv.2503.01381"}],"dataavailabilitystatement":"Data sharing is not applicable to this article as no datasets were generated or analyzed during the current study.","month":"08","supplementarymaterial":"no","author":[{"full_name":"Marcelli, Giovanna","last_name":"Marcelli","first_name":"Giovanna"},{"full_name":"Pigozzi, Lorenzo","last_name":"Pigozzi","first_name":"Lorenzo","id":"efb8f850-3208-11ee-ac71-8c4f5803b9c6"},{"full_name":"Porta, Marcello","last_name":"Porta","first_name":"Marcello"}],"department":[{"_id":"RoSe"},{"_id":"GradSch"}],"researchdata_availability":"not applicable","language":[{"iso":"eng"}],"date_created":"2026-07-26T22:01:40Z","year":"2026","publication_identifier":{"issn":["0377-9017"],"eissn":["1573-0530"]},"article_type":"original","abstract":[{"text":"We consider a class of two-dimensional tight binding models displaying conical intersections of the Bloch bands at the Fermi level. The setting includes the case of generic transitions between quantum Hall phases. We consider the longitudinal conductivity, as given by Kubo formula, describing the variation of the current after introducing a space-homogeneous electric field, in an adiabatic way. We obtain an explicit expression for the longitudinal conductivity, completely determined by the number of conical intersections and by the shape of the cones. In particular, the formula reproduces the known quantized values found for graphene and for the critical Haldane model. Furthermore, we discuss the validity of Kubo formula in presence of conical intersections in the spectrum, starting from the time-dependent Schrödinger equation. For electric fields which are weak and slowly varying in space and in time, we prove the validity of linear response from quantum dynamics.","lang":"eng"}],"quality_controlled":"1","publication":"Letters in Mathematical Physics","intvolume":"       116","type":"journal_article","arxiv":1,"OA_type":"green","scopus_import":"1","article_processing_charge":"No","date_published":"2026-08-01T00:00:00Z","oa":1,"date_updated":"2026-07-29T10:51:55Z","doi":"10.1007/s11005-026-02087-3","volume":116,"oa_version":"Preprint","_id":"22404","citation":{"chicago":"Marcelli, Giovanna, Lorenzo Pigozzi, and Marcello Porta. “Longitudinal Conductivity at Integer Quantum Hall Transitions.” <i>Letters in Mathematical Physics</i>. Springer Nature, 2026. <a href=\"https://doi.org/10.1007/s11005-026-02087-3\">https://doi.org/10.1007/s11005-026-02087-3</a>.","ista":"Marcelli G, Pigozzi L, Porta M. 2026. Longitudinal conductivity at integer quantum Hall transitions. Letters in Mathematical Physics. 116(4), 82.","ieee":"G. Marcelli, L. Pigozzi, and M. Porta, “Longitudinal conductivity at integer quantum Hall transitions,” <i>Letters in Mathematical Physics</i>, vol. 116, no. 4. Springer Nature, 2026.","short":"G. Marcelli, L. Pigozzi, M. Porta, Letters in Mathematical Physics 116 (2026).","mla":"Marcelli, Giovanna, et al. “Longitudinal Conductivity at Integer Quantum Hall Transitions.” <i>Letters in Mathematical Physics</i>, vol. 116, no. 4, 82, Springer Nature, 2026, doi:<a href=\"https://doi.org/10.1007/s11005-026-02087-3\">10.1007/s11005-026-02087-3</a>.","apa":"Marcelli, G., Pigozzi, L., &#38; Porta, M. (2026). Longitudinal conductivity at integer quantum Hall transitions. <i>Letters in Mathematical Physics</i>. Springer Nature. <a href=\"https://doi.org/10.1007/s11005-026-02087-3\">https://doi.org/10.1007/s11005-026-02087-3</a>","ama":"Marcelli G, Pigozzi L, Porta M. Longitudinal conductivity at integer quantum Hall transitions. <i>Letters in Mathematical Physics</i>. 2026;116(4). doi:<a href=\"https://doi.org/10.1007/s11005-026-02087-3\">10.1007/s11005-026-02087-3</a>"},"OA_place":"repository","title":"Longitudinal conductivity at integer quantum Hall transitions","acknowledgement":"G. M. and M. P. acknowledge support by the European Research Council through the ERC-StG MaMBoQ, n. 802901. G. M. acknowledges financial support from the Independent Research Fund Denmark–Natural Sciences, grant DFF–10.46540/2032-00005B and from the European Research Council through the ERC CoG UniCoSM, grant agreement n.724939. M. P. acknowledges support from the MUR, PRIN 2022 project MaIQuFi cod. 20223J85K3. This work has been carried out under the auspices of the GNFM of INdAM. We thank the anonymous referees for comments on a previous version of this manuscript.","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","day":"01","publication_status":"published","mathsc":["81V70"],"external_id":{"arxiv":["2503.01381"]},"article_number":"82","publisher":"Springer Nature","status":"public"}]