{"title":"低次谐波映射的刚度","authors":"Jasmin Horter, T. Lamm, M. Micallef","doi":"10.2422/2036-2145.202201_002","DOIUrl":null,"url":null,"abstract":". In 1981, Sacks and Uhlenbeck introduced their famous α -energy as a way to approxi-mate the Dirichlet energy and produce harmonic maps from surfaces into Riemannian manifolds. However, the second and third authors together with Malchiodi ([11], [12]) showed that for maps between two-spheres this method does not capture every harmonic map. They established a gap theorem for α -harmonic maps of degree zero and also showed that below a certain energy bound α -harmonic maps of degree one are rotations. We establish similar results for ε -harmonic maps u ε : S 2 → S 2 , which are critical points of the ε -energy introduced by the second author in [9]. In particular, we similarly show that ε -harmonic maps of degree zero with energy below 8 π are constant and that maps of degree ± 1 with energy below 12 π are of the form Rx with R ∈ O (3). Moreover, we construct non-trivial ε -harmonic maps of degree zero with energy > 8 π .","PeriodicalId":8132,"journal":{"name":"ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE","volume":"104 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2021-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Rigidity of $\\\\varepsilon$-harmonic maps of low degree\",\"authors\":\"Jasmin Horter, T. Lamm, M. Micallef\",\"doi\":\"10.2422/2036-2145.202201_002\",\"DOIUrl\":null,\"url\":null,\"abstract\":\". In 1981, Sacks and Uhlenbeck introduced their famous α -energy as a way to approxi-mate the Dirichlet energy and produce harmonic maps from surfaces into Riemannian manifolds. However, the second and third authors together with Malchiodi ([11], [12]) showed that for maps between two-spheres this method does not capture every harmonic map. They established a gap theorem for α -harmonic maps of degree zero and also showed that below a certain energy bound α -harmonic maps of degree one are rotations. We establish similar results for ε -harmonic maps u ε : S 2 → S 2 , which are critical points of the ε -energy introduced by the second author in [9]. In particular, we similarly show that ε -harmonic maps of degree zero with energy below 8 π are constant and that maps of degree ± 1 with energy below 12 π are of the form Rx with R ∈ O (3). Moreover, we construct non-trivial ε -harmonic maps of degree zero with energy > 8 π .\",\"PeriodicalId\":8132,\"journal\":{\"name\":\"ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE\",\"volume\":\"104 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2021-12-22\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.2422/2036-2145.202201_002\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.2422/2036-2145.202201_002","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Rigidity of $\varepsilon$-harmonic maps of low degree
. In 1981, Sacks and Uhlenbeck introduced their famous α -energy as a way to approxi-mate the Dirichlet energy and produce harmonic maps from surfaces into Riemannian manifolds. However, the second and third authors together with Malchiodi ([11], [12]) showed that for maps between two-spheres this method does not capture every harmonic map. They established a gap theorem for α -harmonic maps of degree zero and also showed that below a certain energy bound α -harmonic maps of degree one are rotations. We establish similar results for ε -harmonic maps u ε : S 2 → S 2 , which are critical points of the ε -energy introduced by the second author in [9]. In particular, we similarly show that ε -harmonic maps of degree zero with energy below 8 π are constant and that maps of degree ± 1 with energy below 12 π are of the form Rx with R ∈ O (3). Moreover, we construct non-trivial ε -harmonic maps of degree zero with energy > 8 π .