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Abstract

We study two problems closely related to each other. The first one is concerned with some smoothing weighted estimates with weights in a certain Morrey-Campanato spaces, for the solution of the free Schrödinger equation. The second one is a weighed trace inequality.

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... At this point, it should be noted that this local smoothing estimate can be written in terms of a weighted L 2 setting as in (1). Indeed, if ρ is any function such that j∈Z ρ 2 L ∞ (|x|∼2 j ) < ∞, one has Figure 1. ...
... The smoothing effect in the setting (1) can occur due to the decay of the weight |x| −α in the spatial direction. As shown in Figure 1, the smoothing factor σ is indeed related with the decay factor α. At this point, we naturally further ask how much regularity we can expect when considering decay not in the spatial direction but in the space-time direction like |(x, t)| −α . ...
... One is spectral methods based on resolvent estimates, starting from Kato's work [6], and the other is to use Fourier restriction estimates from harmonic analysis (see e.g. [1,18] and references therein). A completely different approach was also recently developed by Ruzhansky and Sugimoto [17] using canonical transforms. ...
... At this point, it is worth noting that this local smoothing estimate can be written in terms of a weighted L 2 norm as in (2). Indeed, if ρ is any function such that j∈Z ρ 2 L ∞ (|x|∼2 j ) < ∞, one has ...
... for V ∈ F p with p > (n − 1)/2, n ≥ 3, which can be found in [5,4] (see also [2,14]). Indeed, applying the re-scaled estimate of (16), ...
... for some − n−2 2 < s < 1 2 and 1 ≤ p < n 2(1−s) . Indeed, Barceló et al [1] obtained this generalized smoothing estimate (1.2) 1 for ...
... 1 Estimate (1.2) was also shown in [1] for the border line p = n 2(1−s) , but in this case L 2(1−s),p = L p . In view of generalization of (1.1) with a singular power weight, we therefore exclude it in (1.2). ...
Preprint
The Kato-Yagima smoothing estimate is a smoothing weighted L2L^2 estimate with a singular power weight for the Schr\"odinger propagator. The weight has been generalized to Morrey-Campanato weights. In this paper we make this generalization more sharp in terms of the so-called Kerman-Sawyer weights. Our result is based on a more sharpened Fourier restriction estimate than previously known ones.
... for some −1 < s ≤ n−2 2 and 1 ≤ p ≤ n 2s+2 . Indeed, Barceló et al [1] obtained the following equivalent estimates ...
... We shall now give an outline of the main ideas in our work. The known approach to Strichartz and smoothing estimates with time-independent weights is based on weighted L 2 bounds for the resolvent operator as well as for the Fourier restriction (see, for example, [31,37,1,3,33]), but it is no longer available in the case of time-dependent weights. Our method that works for this case is completely different from it and is a more fruitful approach which is based on a combination between two kind of arguments, one from the theory of dispersive estimates and the other one from weighted inequalities. ...
Article
The primary objective in this paper is to give an answer to an open question posed by J. A. Barcel\'o, J. M. Bennett, A. Carbery, A. Ruiz and M. C. Vilela concerning the problem of determining the optimal range on s0s\geq0 and p1p\geq1 for which the following Strichartz estimate with time-dependent weights w in Morrey-Campanato type classes L22s+2,p\mathfrak{L}^{2s+2,p}_2 holds: \begin{equation}\label{absset} \|e^{it\Delta}f\|_{L_{x,t}^2(w(x,t))}\leq C\|w\|_{\mathfrak{L}^{2s+2,p}_2}^{1/2}\|f\|_{\dot{H}^s}. \end{equation} Beyond the case s0s\geq0, we further ask in this paper how much regularity we can expect on this setting. But interestingly, it turns out that this estimate is false whenever s<0s<0, which shows that the smoothing effect cannot occur in this time-dependent setting and the dispersion in the Schr\"odinger flow eitΔe^{it\Delta} is not strong enough to have the effect. This naturally leads us to consider the possibility of having the effect at best in higher-order versions of this estimate with eit(Δ)γ/2e^{-it(-\Delta)^{\gamma/2}} (γ>2\gamma>2) whose dispersion is more strong. We do obtain a smoothing effect exactly for these higher-order versions. More generally, we will obtain the estimates where γ1\gamma\geq1 in a unified manner and also their corresponding inhomogeneous estimates to give applications to the global well-posedness in a weighted setting for Schr\"odinger and wave equations (as well as linearized KdV equations) with small time-dependent perturbations. This is our secondary objective in this paper.
... One is spectral methods based on resolvent estimates, starting from Kato's work [7], and the other is to make use of Fourier restriction estimates from harmonic analysis (see e.g. [1,19] and references therein). A completely different approach was also recently developed by Ruzhansky and Sugimoto [18] using canonical transforms. ...
Preprint
We obtain some new Morawetz estimates for the Klein-Gordon flow of the form \begin{equation*} \big\||\nabla|^{\sigma} e^{it \sqrt{1-\Delta}}f \big\|_{L^2_{x,t}(|(x,t)|^{-\alpha})} \lesssim \|f\|_{H^s} \end{equation*} where σ,s0\sigma,s\geq0 and α>0\alpha>0. The conventional approaches to Morawetz estimates with xα|x|^{-\alpha} are no longer available in the case of time-dependent weights (x,t)α|(x,t)|^{-\alpha}. Here we instead apply the Littlewood-Paley theory with Muckenhoupt A2A_2 weights to frequency localized estimates thereof that are obtained by making use of the bilinear interpolation between their bilinear form estimates which needs to carefully analyze some relevant oscillatory integrals according to the different scaling of 1Δ\sqrt{1-\Delta} for low and high frequencies.
... for V ∈ F p with p > (n − 1)/2, n ≥ 3, which can be found in [5,4] (see also [2,14]). Indeed, applying the re-scaled estimate of (2.4), ...
Preprint
We prove weighted L2L^2 estimates for the Klein-Gordon equation perturbed with singular potentials such as the inverse-square potential. We then deduce the well-posedness of the Cauchy problem for this perturbed equation. We go on to discuss local smoothing and Strichartz estimates which improve previously known ones.
... One can also see [1], [2], [14] for related work. An explicit weight, |x| s dx dt, is discussed in [10] (see (2.6) there). ...
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We prove that if the Hausdorff dimension of ERdE\subset\mathbb{R}^d, d2d\geq 2 is greater than d2+13\frac{d}{2}+\frac{1}{3}, there exists xEx\in E such that the pinned distance set Δx(E)={yx:yE}\Delta_x(E)=\{|y-x|: y\in E \} has positive Lebesgue measure. This improves a result of Peres and Schlag. The key new ingredient in our proof is the following identity. Using a group action argument, we show that for any Schwartz function f on Rd\mathbb{R}^d and any xRdx\in\mathbb{R}^d, 0ωtf(x)2td1dt=0ωr^f(x)2rd1dr,\int_0^\infty |\omega_t*f(x)|^2\,t^{d-1}dt\,=\int_0^\infty|\widehat{\omega_r}*f(x)|^2\,r^{d-1}dr, where ωr\omega_r is the normalized surface measure on rSd1r S^{d-1}. An interesting remark is that the right hand side can be easily seen equals cd0Dxd12e2πitΔf(x)2dt=cd0Dxd22e2πitΔf(x)2dt,c_d\int_0^\infty\left|D_x^{-\frac{d-1}{2}}e^{-2\pi i t\sqrt{-\Delta}}f(x)\right|^2\,dt=c_d'\int_0^\infty\left|D_x^{-\frac{d-2}{2}}e^{2\pi i t\Delta}f(x)\right|^2\,dt, where Δ\Delta is the standard Laplacian and Dxα=(Δ)α2D_x^\alpha=(-\Delta)^{\frac{\alpha}{2}}.
... but we can use Lemma 2.1 to shows that this inequality is equivalent to (2.8). See also [1]. Special cases of the restriction inequality in [23] are in [8] and [9]. ...
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We prove new Pitt inequalities for the Fourier transforms with radial and non-radial weights using weighted restriction inequalities for the Fourier transform on the sphere. We also prove new Riemann-Lebesgue estimates and versions of the uncertainty principle for the Fourier transform.
... Taking the sup in t was sometimes used for time-dependent potentials in other problems ( [39,40,4,2,3]) concerning Schrödinger equations. Since |V (x, t)| ≤ W (x) for almost every t, the following corollary is an immediate consequence of Theorem 1.4 and is expected to lead to unique continuation for time-dependent potentials. ...
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In this paper we develop a new method to handle the problem of unique continuation for the Schr\"odinger equation. In general the problem is to find a class of potentials which allow the unique continuation. The key point of our work is to develop a direct link between the problem and weighted L2L^2 resolvent estimates with potentials as weights. We carry out it in an abstract way, and thereby we do not need to deal with each of the potential classes. In doing so, we will make use of limiting absorption principle and Kato H-smoothing theorem in spectral theory, and employ some tools from harmonic analysis. Once the resolvent estimate is set up for a potential class, from our abstract theory the unique continuation would follow from the same potential class. In this regard, another main issue for us is to know which class of potentials allows the resolvent estimate. We establish such a new class which contains the previously known ones. As a consequence, we obtain new results on the unique continuation. Our resolvent estimates may have further applications for other related problems such as well-posedness. We will also deal with that problem.
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The Kato–Yajima smoothing estimate is a smoothing weighted L2 estimate with a singular power weight for the Schrödinger propagator. The weight has been generalized relatively recently to Morrey–Campanato weights. In this paper we make this generalization more sharp in terms of the so‐called Kerman–Sawyer weights. Our result is based on a more sharpened Fourier restriction estimate in a weighted L2 space. Obtained results are also extended to the fractional Schrödinger propagator.
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Let us consider in a domain O of Rn solutions of the differential inequality |?u(x)| = V(x)|u(x)|, x I O, where V is a non smooth, positive potential. We are interested in global unique continuation properties. That means that u must be identically zero on O if it vanishes on an open subset of O.
Unique continuation for Schrödinger operators with potential in Morrey spaces " and a remark on interpolation of Morrey spaces [7] , Local regularity of solutions to wave equations with time-dependent potentials, Duke Math
[6] , Corrigenda to: " Unique continuation for Schrödinger operators with potential in Morrey spaces " and a remark on interpolation of Morrey spaces, Publ. Mat. 39 (1995), no. 2, 405–411. [7] , Local regularity of solutions to wave equations with time-dependent potentials, Duke Math. J. 76 (1994), no. 3, 913–940.
Unique continuation for Schrödinger operators with potential in Morrey spaces" and a remark on interpolation of Morrey spaces
  • Corrigenda To
, Corrigenda to: "Unique continuation for Schrödinger operators with potential in Morrey spaces" and a remark on interpolation of Morrey spaces, Publ. Mat. 39 (1995), no. 2, 405-411.