Research output: Contribution to journal › Article › peer-review
Extensions self-adjointes et anti-symétriques du laplacien, avec condition à la frontière de type Robin singulière. / Nazarov, S.A.; Popoff, N.
In: Comptes Rendus Mathematique, Vol. 356, No. 9, 09.2018, p. 927-932.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Extensions self-adjointes et anti-symétriques du laplacien, avec condition à la frontière de type Robin singulière
AU - Nazarov, S.A.
AU - Popoff, N.
N1 - Funding Information: This work is supported by grant 17-11-01003 of the Russian Science Foundation . It is also supported by the Chair BOLIDE funded by the IDEX Bordeaux and by the project PEPS JC 2017.
PY - 2018/9
Y1 - 2018/9
N2 - We study the Laplacian in a bounded domain, with a varying Robin boundary condition singular at one point. The associated quadratic form is not semi-bounded from below, and the corresponding Laplacian is not self-adjoint, it has a residual spectrum covering the whole complex plane. We describe its self-adjoint extensions and exhibit a physically relevant skew-symmetric one. We approximate the boundary condition, giving rise to a family of self-adjoint operators, and we describe its spectrum by the method of matched asymptotic expansions. A part of the spectrum acquires a strange behavior when the small perturbation parameter ε>0 tends to zero, namely it becomes almost periodic in the logarithmic scale |lnε|, and in this way “wanders” along the real axis at a speed O(ε −1).
AB - We study the Laplacian in a bounded domain, with a varying Robin boundary condition singular at one point. The associated quadratic form is not semi-bounded from below, and the corresponding Laplacian is not self-adjoint, it has a residual spectrum covering the whole complex plane. We describe its self-adjoint extensions and exhibit a physically relevant skew-symmetric one. We approximate the boundary condition, giving rise to a family of self-adjoint operators, and we describe its spectrum by the method of matched asymptotic expansions. A part of the spectrum acquires a strange behavior when the small perturbation parameter ε>0 tends to zero, namely it becomes almost periodic in the logarithmic scale |lnε|, and in this way “wanders” along the real axis at a speed O(ε −1).
UR - http://www.scopus.com/inward/record.url?scp=85049871924&partnerID=8YFLogxK
U2 - 10.1016/j.crma.2018.07.001
DO - 10.1016/j.crma.2018.07.001
M3 - статья
VL - 356
SP - 927
EP - 932
JO - Comptes Rendus Mathematique
JF - Comptes Rendus Mathematique
SN - 1631-073X
IS - 9
ER -
ID: 35209824