Limitations of Caldeira-Leggett model for description of phase transitions in superconducting circuits
| Autor: | Kashuba, O., Riwar, R. -P. |
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| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 110, 184505 (2024) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.110.184505 |
| Popis: | The inherent complexity of system-bath interactions often requires making critical approximations, which we here show to have a radical influence on the renormalization group flow and the resulting phase diagram. Specifically, for the Caldeira-Leggett model Schmid and Bulgadaev (SB) predicted a phase transition, whose experimental verification in resistive superconducting circuits is currently hotly debated. For normal metal and Josephson junction array resistors, we show that the mapping to Caldeira-Leggett is only exact when applying approximations which decompactify the superconducting phase. We show that there exist treatments that retain phase compactness, which immediately lead to a phase diagram depending on four instead of two parameters. While we still find an SB-like transition in the transmon regime, the critical parameter is controlled exclusively by the capacitive coupling. In contrast, the Cooper pair box maps to the anisotropic Kondo model, where a pseudoferromagnetic phase is not allowed for regular electrostatic interactions. Comment: 10 pages, 2 figures. Supplemental material at the end of file (after bibliography). Feedback is welcome |
| Databáze: | arXiv |
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