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Department of quantum mesoscopics: seminar, Friday, April 17, 2026, ITF, 3:00 pm D.S. Katkov, M.V. Parfenov, I.S. Burmistrov Mikroskopicheskaya model' kiral'nykh fermionov dlya spinovogo kvantovogo effekta Kholla. Spinovyi kvantovyi effekt Kholla yavlyaetsya rodstvennikom tselochislennogo kvantovogo effekta Kholla, kharakterizuyushchegosya tselochislenno kvantovannoi spinovoi khollovskoi provodimost'yu. V dannoi rabote formuliruetsya i issleduetsya model' odnomernykh provodakh s N kanalov na kazhdom i so sluchainym tunnelirovaniem mezhdu kanalami. Rassmatrivaemaya model' sokhranyaet fundamental'nye simmetrii spinovogo kvantovogo effekta Kholla. Prodemonstrirovano, chto v obshchem sluchae tripletnyi sektor teorii ne ottseplyaetsya ot singletnogo sektora. V predele bol'shikh N sistematicheski vyvoditsya effektivnaya krupnomasshtabnaya nizkoenergeticheskaya teoriyu polya, predstavlyayushchaya soboi nelineinuyu sigma-model'. Analiz pokazyvaet, chto, khotya tripletnye mody obychno massivny i ne vliyayut na nelineinuyu sigma-model' bol'shikh N, sushchestvuyut opredelennye usloviya, pri kotorykh eti mody stanovyatsya «myagkimi», tem samym uvelichivaya dlinu ul'trafioletovoi obrezki modeli. Krome togo, pri vychislenii zatravochnykh prodol'noi i khollovskoi spinovykh provodimostei, obnaruzhivaetsya, chto standartnoe priblizhenie sedlovoi tochki ne rabotaet v rezhimakh so znachitel'noi tunnel'noi asimmetriei mezhdu chetnymi i nechetnymi zven'yami. Ustanavlivleno, chto vvedenie zeemanovskogo polya ne tol'ko narushaet simmetriyu SU(2) deistviya nelineinoi sigma-modeli, no i porozhdaet chlen, kotoryi yavno narushaet inversionnuyu simmetriyu. |
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