Asymptotics with sharp remainder estimates are recovered for number of eigenvalues of operator crossing level as runs from to , . Here is periodic matrix operator, matrix is positive, periodic with respect to first copy of and decaying as second copy of goes to infinity, either belongs to a spectral gap of or is one its ends. These problems are first treated in papers of M. Sh. Birman, M. Sh. Birman-A. Laptev and M. Sh. Birman-T. Suslina.
@incollection{JEDP_1999____A5_0, author = {Victor Ivrii}, title = {Accurate {Spectral} {Asymptotics} for periodic operators}, booktitle = {}, series = {Journ\'ees \'equations aux d\'eriv\'ees partielles}, eid = {5}, pages = {1--11}, publisher = {Universit\'e de Nantes}, year = {1999}, zbl = {01810578}, mrnumber = {2000h:35125}, language = {en}, url = {https://proceedings.centre-mersenne.org/item/JEDP_1999____A5_0/} }
Victor Ivrii. Accurate Spectral Asymptotics for periodic operators. Journées équations aux dérivées partielles (1999), article no. 5, 11 p. https://proceedings.centre-mersenne.org/item/JEDP_1999____A5_0/
[B1] M. Birman. The discrete spectrum in gaps of the perturbed periodic Schrödinger operator. I. Regularperturbations. Boundary value problems, Schrödinger operators, deformation quantization, Math. Top., 8, Akademie Verlag, Berlin, 1995, pp. 334-352. | MR | Zbl
[B2] M. Birman. The discrete spectrum of the periodic Schrödinger operator perturbed by a decreasing potential. St. Petersburg Math. J., 8 (1997), no. 1, pp. 1-14. | MR | Zbl
[B3] M. Birman. Discrete spectrum in the gaps of the perturbed periodic Schrödinger operator. II. Non-regular perturbations. St. Petersburg Math. J., 9 (1998), no. 6, pp. 1073-1095. | MR | Zbl
[BL1] M. Birman, A. Laptev. The negative discrete spectrum of a two-dimensional Schrödinger operator. Comm. Pure Appl. Math., 49 (1996), no. 9, pp. 967-997. | MR | Zbl
[BL2] M. Birman, A. Laptev. «Non-standard» spectral asymptotics for a two-dimensional Schrödinger operator. Centre de Recherches Mathematiques, CRM Proceedings and Lecture Notes, 12 (1997), pp. 9-16. | MR | Zbl
[BLS] M. Birman, A. Laptev, T. Suslina. Discrete spectrum of the twodimensional periodic elliptic second order operator perturbed by a decreasing potential. I. Semiinfinite gap (in preparation). | Zbl
[BS] M. Birman, T. Suslina. Birman, Suslina. Discrete spectrum of the twodimensional periodic elliptic second order operator perturbed by a decreasing potential. II. Internal gaps (in preparation). | Zbl
[Ivr1] V. Ivrii. Microlocal Analysis and Precise Spectral Asymptotics. Springer-Verlag, SMM, 1998, 731+15 pp. | MR | Zbl
[Ivr2] V. Ivrii. Accurate Spectral Asymptotics for Neumann Laplacian in domains with cusps (to appear in Applicable Analysis).
[JMS] V. Jakšić, S. Molčanov and B. Simon. Eigenvalue asymptotics of the Neumann Laplacian of regions and manifolds with cusps. J. Func. Anal., 106, (1992), pp. 59-79. | MR | Zbl
[Sol1] M. Solomyak. On the negative discrete spectrum of the operator -ΔN -αV for a class of unbounded domains in Rd, CRM Proceedings and Lecture Notes, Centre de Recherches Mathematiques, 12, (1997), pp. 283-296. | MR | Zbl