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Almost everywhere convergence of Bochner-Riesz means for the Hermite operators. (English) Zbl 1476.42005

Summary: Let \(H = - \Delta + | x |^2\) be the Hermite operator in \(\mathbb{R}^n\). In this paper we study almost everywhere convergence of the Bochner-Riesz means associated with \(H\) which is defined by \(S_R^\lambda(H) f(x) = \sum_{k = 0}^\infty ( 1 - \frac{ 2 k + n}{ R^2} )_+^\lambda P_k f(x)\). Here \(P_k f\) is the \(k\)-th Hermite spectral projection operator. For \(2 \leq p < \infty \), we prove that \[ \lim_{R \to \infty} S_R^\lambda(H) f = f \text{ a.e. }\] for all \(f \in L^p( \mathbb{R}^n)\) provided that \(\lambda > \lambda(p) / 2\) and \(\lambda(p) = \max \{n(1 / 2 - 1 / p) - 1 / 2, 0 \} \). Conversely, we also show the convergence generally fails if \(\lambda < \lambda(p) / 2\) in the sense that there is an \(f \in L^p( \mathbb{R}^n)\) for \(2 n /(n - 1) \leq p\) such that the convergence fails. This is in surprising contrast with a.e. convergence of the classical Bochner-Riesz means for the Laplacian. For \(n \geq 2\) and \(p \geq 2\) our result tells that the critical summability index for a.e. convergence for \(S_R^\lambda(H)\) is as small as only the half of the critical index for a.e. convergence of the classical Bochner-Riesz means. When \(n = 1\), we show a.e. convergence holds for \(f \in L^p(\mathbb{R})\) with \(p \geq 2\) whenever \(\lambda > 0\). Compared with the classical result due to R. Askey and S. Wainger [Am. J. Math. 87, 695–708 (1965; Zbl 0125.31301)] who showed the optimal \(L^p\) convergence for \(S_R^\lambda(H)\) on \(\mathbb{R}\) we only need smaller summability index for a.e. convergence.

MSC:

42B15 Multipliers for harmonic analysis in several variables
42B25 Maximal functions, Littlewood-Paley theory
47F05 General theory of partial differential operators

Citations:

Zbl 0125.31301

References:

[1] Annoni, M., Almost everywhere convergence for modified Bochner-Riesz means at the critical index for \(p \geq 2\), Pac. J. Math., 286, 257-275 (2017) · Zbl 1366.42012
[2] Askey, R.; Wainger, S., Mean convergence of expansions in Laguerre and Hermite series, Am. J. Math., 87, 695-708 (1965) · Zbl 0125.31301
[3] Bergh, J.; Löfström, J., Interpolation Spaces. An Introduction, Grundlehren der Mathematischen Wissenschaften, vol. 223 (1976), Springer-Verlag: Springer-Verlag Berlin-New York · Zbl 0344.46071
[4] Bongioanni, B.; Rogers, K., Regularity of the Schrödinger equation for the harmonic oscillator, Ark. Mat., 49, 217-238 (2011) · Zbl 1252.35238
[5] Bourgain, J.; Guth, L., Bounds on oscillatory integral operators based on multilinear estimates, Geom. Funct. Anal., 21, 1239-1295 (2011) · Zbl 1237.42010
[6] Calderón, A.-P., Intermediate spaces and interpolation, the complex method, Stud. Math., 24, 113-190 (1964) · Zbl 0204.13703
[7] Carbery, A., The boundedness of the maximal Bochner-Riesz operator on \(L^4( \mathbb{R}^2)\), Duke Math. J., 50, 409-416 (1983) · Zbl 0522.42015
[8] Carbery, A.; Rubio de Francia, J. L.; Vega, L., Almost everywhere summability of Fourier integrals, J. Lond. Math. Soc., 38, 513-524 (1988) · Zbl 0631.42004
[9] Carbery, A.; Soria, F., Almost everywhere convergence of Fourier integrals for functions in Sobolev spaces, and an \(L^2\) localisation principle, Rev. Mat. Iberoam., 4, 2, 319-337 (1988) · Zbl 0692.42001
[10] Carleson, L.; Sjölin, P., Oscillatory integrals and a multiplier problem for the disc, Stud. Math., 44, 287-299 (1972) · Zbl 0215.18303
[11] Chen, P.; Hebisch, W.; Sikora, A., Bochner-Riesz profile of anharmonic oscillator \(L = - \frac{ d^2}{ d x^2} + | x |\), J. Funct. Anal., 271, 11, 3186-3241 (2016) · Zbl 1350.42044
[12] Chen, P.; Lee, S.; Sikora, A.; Yan, L. X., Bounds on the maximal Bochner-Riesz means for elliptic operators, Trans. Am. Math. Soc., 373, 3793-3828 (2020) · Zbl 1440.42044
[13] Chen, P.; Ouhabaz, E. M.; Sikora, A.; Yan, L. X., Restriction estimates, sharp spectral multipliers and endpoint estimates for Bochner-Riesz means, J. Anal. Math., 129, 219-283 (2016) · Zbl 1448.47033
[14] Christ, M., On almost everywhere convergence for Bochner-Riesz means in higher dimensions, Proc. Am. Math. Soc., 95, 155-167 (1985)
[15] Cordes, H. O., Spectral Theory of Linear Differential Operators and Comparison Algebras, London Mathematical Society Lecture Note Series, vol. 76 (1987), Cambridge University Press: Cambridge University Press Cambridge · Zbl 0727.35092
[16] Coulhon, T.; Sikora, A., Gaussian heat kernel upper bounds via the Phragmén-Lindelöf theorem, Proc. Lond. Math. Soc., 96, 507-544 (2008) · Zbl 1148.35009
[17] Cowling, M.; Sikora, A., A spectral multiplier theorem for a sublaplacian on SU(2), Math. Z., 238, 1, 1-36 (2001) · Zbl 0996.42006
[18] de Guzmán, M., Real variable methods in Fourier analysis, (Notas de Matemätica (75). Notas de Matemätica (75), North-Holland Mathematics Studies, vol. 46 (1981), North-Holland Publishing Co.: North-Holland Publishing Co. Amsterdam-New York), xiii+392 pp · Zbl 0449.42001
[19] Duong, X. T.; Ouhabaz, E. M.; Sikora, A., Plancherel-type estimates and sharp spectral multipliers, J. Funct. Anal., 196, 443-485 (2002) · Zbl 1029.43006
[20] Duong, X. T.; Sikora, A.; Yan, L. X., Weighted norm inequalities, Gaussian bounds and sharp spectral multipliers, J. Funct. Anal., 260, 1106-1131 (2011) · Zbl 1250.42042
[21] Fefferman, C., The multiplier problem for the ball, Ann. Math., 94, 330-336 (1971) · Zbl 0234.42009
[22] Galé, J. E.; Pytlik, T., Functional calculus for infinitesimal generators of holomorphic semigroups, J. Funct. Anal., 150, 307-355 (1997) · Zbl 0897.43002
[23] Garciá-Cuerva, J.; Rubio de Francia, J. L., Weighted Inequalities and Related Topics, North-Holland Math. Stud., vol. 116 (1985) · Zbl 0578.46046
[24] Gorges, D.; Müller, D., Almost everywhere convergence of Bochner-Riesz means on the Heisenberg group and fractional integration on the dual, Proc. Lond. Math. Soc., 85, 139-167 (2002) · Zbl 1013.43003
[25] Grafakos, L., Classical Fourier Analysis, Graduate Texts in Mathematics, vol. 249 (2014), Springer: Springer New York · Zbl 1304.42001
[26] Guth, L.; Hickman, J.; Iliopoulou, M., Sharp estimates for oscillatory integral operators via polynomial partitioning, Acta Math., 223, 2, 251-376 (2019) · Zbl 1430.42016
[27] Herz, C., On the mean inversion of Fourier and Hankel transform, Proc. Natl. Acad. Sci. USA, 40, 996-999 (1954) · Zbl 0059.09901
[28] Hörmander, L., The Analysis of Linear Partial Differential Operators, I, II (1983), Springer-Verlag: Springer-Verlag Berlin · Zbl 0521.35002
[29] Horwich, A. D.; Martini, A., Almost everywhere convergence of Bochner-Riesz means on Heisenberg-type groups, J. Lond. Math. Soc. (2), 103, 3, 1066-1119 (2021) · Zbl 1503.22009
[30] Jeong, E.; Lee, S.; Ryu, J., Estimates for the Hermite spectral projection, available at
[31] Karadzhov, G. B., Riesz summability of multiple Hermite series in \(L^p\) spaces, C. R. Acad. Bulgare Sci., 47, 5-8 (1994) · Zbl 0829.40003
[32] Karadzhov, G. B., Riesz summability of multiple Hermite series in \(L^p\) spaces, Math. Z., 219, 107-118 (1995) · Zbl 0824.42019
[33] Kenig, C.; Stanton, R. J.; Tomas, P., Divergence of eigenfunction expansions, J. Funct. Anal., 46, 1, 28-44 (1982) · Zbl 0506.47014
[34] Koch, H.; Tataru, D., \( L^p\) eigenfunction bounds for the Hermite operator, Duke Math. J., 128, 369-392 (2005) · Zbl 1075.35020
[35] Lee, S., Improved bounds for Bochner-Riesz and maximal Bochner-Riesz operators, Duke Math. J., 122, 205-232 (2004) · Zbl 1072.42009
[36] Lee, S., Square function estimates for the Bochner-Riesz means, Anal. PDE, 11, 1535-1586 (2018) · Zbl 1414.42010
[37] Lee, S.; Ryu, J., Bochner-Riesz means for the Hermite and special Hermite expansions, available at · Zbl 1486.42044
[38] Lee, S.; Seeger, A., On radial Fourier multipliers and almost everywhere convergence, J. Lond. Math. Soc., 91, 105-126 (2015) · Zbl 1327.42014
[39] Li, X.; Wu, S., New estimates of maximal Bochner-Riesz operator in the plane, Math. Ann., 378, 3-4, 873-890 (2020) · Zbl 1453.42015
[40] Muckenhoupt, B., Mean convergence of Hermite and Laguerre series. II, Trans. Am. Math. Soc., 147, 433-460 (1970) · Zbl 0191.07602
[41] Stein, E. M., Harmonic analysis: real variable methods, orthogonality and oscillatory integrals, (Monographs in Harmonic Analysis, III. Monographs in Harmonic Analysis, III, Princeton Mathematical Series, vol. 43 (1993), Princeton University Press: Princeton University Press Princeton, NJ), with the assistance of Timothy S. Murphy · Zbl 0821.42001
[42] Stein, E. M.; Weiss, G., Introduction to Fourier Analysis on Euclidean Spaces (1971), Princeton Univ. Press: Princeton Univ. Press Princeton, NJ · Zbl 0232.42007
[43] Stein, E. M.; Weiss, G., Interpolation of operators with change of measures, Trans. Am. Math. Soc., 87, 159-172 (1958) · Zbl 0083.34301
[44] Tao, T., The weak-type endpoint Bochner-Riesz conjecture and related topics, Indiana Univ. Math. J., 47, 1097-1124 (1998) · Zbl 0926.42011
[45] Tao, T., On the maximal Bochner-Riesz conjecture in the plane for \(p < 2\), Trans. Am. Math. Soc., 354, 5, 1947-1959 (2002) · Zbl 0992.42003
[46] Tao, T., Recent progress on the restriction conjecture, (Fourier Analysis and Convexity (2004), Birkhäuser Boston: Birkhäuser Boston Boston, MA), 217-243 · Zbl 1083.42008
[47] Tao, T.; Vargas, A.; Vega, L., A bilinear approach to the restriction and Kakeya conjecture, J. Am. Math. Soc., 11, 967-1000 (1998) · Zbl 0924.42008
[48] Thangavelu, S., Summability of Hermite expansions I, Trans. Am. Math. Soc., 314, 119-142 (1989) · Zbl 0685.42015
[49] Thangavelu, S., Summability of Hermite expansions II, Trans. Am. Math. Soc., 314, 143-170 (1989) · Zbl 0685.42016
[50] Thangavelu, S., On almost everywhere and mean convergence of Hermite and Laguerre expansions, Colloq. Math., 60/61, 21-34 (1990) · Zbl 0747.42014
[51] Thangavelu, S., Lecture on Hermite and Laguerre Expansions (1993), Princeton Univ. Press: Princeton Univ. Press Princeton, NJ, (with a preface by Robert S. Strichartz) · Zbl 0821.43005
[52] Thangavelu, S., Hermite and special Hermite expansions revisited, Duke Math. J., 94, 257-278 (1998) · Zbl 0945.42014
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