{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T11:44:52Z","timestamp":1779882292999,"version":"3.53.1"},"reference-count":23,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2022,11,18]],"date-time":"2022-11-18T00:00:00Z","timestamp":1668729600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Istituto Nazionale di Fisica Nucleare (Italy)","award":["FEEL"],"award-info":[{"award-number":["FEEL"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>Measurements indicating that planar networks of superconductive islands connected by Josephson junctions display long-range quantum coherence are reported. The networks consist of superconducting islands connected by Josephson junctions and have a tree-like topological structure containing no loops. Enhancements of superconductive gaps over specific branches of the networks and sharp increases in pair currents are the main signatures of the coherent states. In order to unambiguously attribute the observed effects to branches being embedded in the networks, comparisons with geometrically equivalent\u2014but isolated\u2014counterparts are reported. Tuning the Josephson coupling energy by an external magnetic field generates increases in the Josephson currents, along the above-mentioned specific branches, which follow a functional dependence typical of phase transitions. Results are presented for double comb and star geometry networks, and in both cases, the observed effects provide positive quantitative evidence of the predictions of existing theoretical models.<\/jats:p>","DOI":"10.3390\/e24111690","type":"journal-article","created":{"date-parts":[[2022,11,21]],"date-time":"2022-11-21T03:07:23Z","timestamp":1669000043000},"page":"1690","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Quantum Coherence in Loopless Superconductive Networks"],"prefix":"10.3390","volume":"24","author":[{"given":"Massimiliano","family":"Lucci","sequence":"first","affiliation":[{"name":"Dipartimento di Fisica and MINAS Lab, Universit\u00e0 di Roma \u201cTor Vergata\u201d, 00133 Roma, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Valerio","family":"Campanari","sequence":"additional","affiliation":[{"name":"Dipartimento di Elettronica, Universit\u00e0 di Roma \u201cTor Vergata\u201d, 00133 Roma, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Davide","family":"Cassi","sequence":"additional","affiliation":[{"name":"Dipartimento di Scienze Matematiche, Fisiche ed Informatiche, Universit\u00e0 di Parma, 43124 Parma, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4858-3714","authenticated-orcid":false,"given":"Vittorio","family":"Merlo","sequence":"additional","affiliation":[{"name":"Dipartimento di Fisica and MINAS Lab, Universit\u00e0 di Roma \u201cTor Vergata\u201d, 00133 Roma, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6322-7374","authenticated-orcid":false,"given":"Francesco","family":"Romeo","sequence":"additional","affiliation":[{"name":"Dipartimento di Fisica \u201cE. 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Caianiello\u201d, Universit\u00e0 di Salerno, 84084 Fisciano, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1767-0724","authenticated-orcid":false,"given":"Gaetano","family":"Salina","sequence":"additional","affiliation":[{"name":"Istituto Nazionale di Fisica Nucleare, Sezione Roma Tor Vergata, 00133 Roma, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matteo","family":"Cirillo","sequence":"additional","affiliation":[{"name":"Dipartimento di Fisica and MINAS Lab, Universit\u00e0 di Roma \u201cTor Vergata\u201d, 00133 Roma, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,11,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1165","DOI":"10.1103\/PhysRevLett.42.1165","article-title":"Possibility of Vortex-Antivortex Pair Dissociation in Two-Dimensional Superconductors","volume":"42","author":"Beasley","year":"1979","journal-title":"Phys. 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