Spectral projections for the twisted Laplacian

Herbert Koch ; Fulvio Ricci

Studia Mathematica, Tome 178 (2007), p. 103-110 / Harvested from The Polish Digital Mathematics Library

Résumé

Let n ≥ 1, d = 2n, and let (x,y) ∈ ℝⁿ × ℝⁿ be a generic point in ℝ²ⁿ. The twisted Laplacian $L = -1/2 ∑_{j=1}^{n} [(∂_{x_{j}} + iy_{j})² + (∂_{y_{j}} - ix_{j})²]$ has the spectrum n + 2k = λ²: k a nonnegative integer. Let $P_{λ}$ be the spectral projection onto the (infinite-dimensional) eigenspace. We find the optimal exponent ϱ(p) in the estimate $||P_{λ}u||_{L^{p}(ℝ^{d})} ≲ λ^{ϱ(p)} ||u||_{L²(ℝ^{d})}$ for all p ∈ [2,∞], improving previous partial results by Ratnakumar, Rawat and Thangavelu, and by Stempak and Zienkiewicz. The expression for ϱ(p) is ϱ(p) = 1/p -1/2 if 2 ≤ p ≤ 2(d+1)/(d-1), ϱ(p) = (d-2)/2 - d/p if 2(d+1)/(d-1) ≤ p ≤ ∞.

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Publié le : 2007-01-01

Zbl 1120.43005

EUDML-ID : urn:eudml:doc:285179