{ "id": "1204.1159", "version": "v1", "published": "2012-04-05T09:27:49.000Z", "updated": "2012-04-05T09:27:49.000Z", "title": "Weighted Plancherel estimates and sharp spectral multipliers for the Grushin operators", "authors": [ "Alessio Martini", "Adam Sikora" ], "journal": "Mathematical Research Letters, 19 no. 5 (2012), p. 1075-1088", "categories": [ "math.AP" ], "abstract": "We study the Grushin operators acting on $\\R^{d_1}_{x'}\\times \\R^{d_2}_{x\"}$ and defined by the formula \\[ L=-\\sum_{\\jone=1}^{d_1}\\partial_{x'_\\jone}^2 - (\\sum_{\\jone=1}^{d_1}|x'_\\jone|^2) \\sum_{\\jtwo=1}^{d_2}\\partial_{x\"_\\jtwo}^2. \\] We obtain weighted Plancherel estimates for the considered operators. As a consequence we prove $L^p$ spectral multiplier results and Bochner-Riesz summability for the Grushin operators. These multiplier results are sharp if $d_1 \\ge d_2$. We discuss also an interesting phenomenon for weighted Plancherel estimates for $d_1