scholarly journals Heat kernel asymptotic expansions for the Heisenberg sub-Laplacian and the Grushin operator

2015 ◽  
Vol 471 (2175) ◽  
pp. 20140943
Author(s):  
Der-Chen Chang ◽  
Yutian Li
Keyword(s):  
Stationary Phase ◽  
Heisenberg Group ◽  
Heat Kernel ◽  
Asymptotic Expansions ◽  
Small Time ◽  
Heat Kernels ◽  
Grushin Operator ◽  
Geodesic Structure ◽  
Laplace Type ◽  
Method Of Steepest Descent

The sub-Laplacian on the Heisenberg group and the Grushin operator are typical examples of sub-elliptic operators. Their heat kernels are both given in the form of Laplace-type integrals. By using Laplace's method, the method of stationary phase and the method of steepest descent, we derive the small-time asymptotic expansions for these heat kernels, which are related to the geodesic structure of the induced geometries.

The Heat Kernel and Green's Function on a Manifold with Heisenberg Group as Boundary

2004 ◽  
Vol 56 (3) ◽  
pp. 590-611
Author(s):  
Yilong Ni
Keyword(s):  
Riemannian Manifold ◽  
Heisenberg Group ◽  
Green’S Function ◽  
Heat Kernel ◽  
Green's Function ◽  
Beltrami Operator ◽  
Small Time ◽  
Time Estimates

AbstractWe study the Riemannian Laplace-Beltrami operator L on a Riemannian manifold with Heisenberg group H1 as boundary. We calculate the heat kernel and Green's function for L, and give global and small time estimates of the heat kernel. A class of hypersurfaces in this manifold can be regarded as approximations of H1. We also restrict L to each hypersurface and calculate the corresponding heat kernel and Green's function. We will see that the heat kernel and Green's function converge to the heat kernel and Green's function on the boundary.

scholarly journals UNIQUENESS OF SOLUTIONS TO SCHRÖDINGER EQUATIONS ON -TYPE GROUPS

2013 ◽  
Vol 95 (3) ◽  
pp. 297-314 ◽  
Author(s):  
SALEM BEN SAÏD ◽  
SUNDARAM THANGAVELU ◽  
VENKU NAIDU DOGGA
Keyword(s):  
Initial Data ◽  
Heisenberg Group ◽  
Heat Kernel ◽  
Schrodinger Equation ◽  
Analogous Result ◽  
General Context ◽  
Uniqueness Of Solutions ◽  
Grushin Operator ◽  
Alpha Beta ◽  
Formula Type

AbstractThis paper deals with the Schrödinger equation $i{\partial }_{s} u(\mathbf{z} , t; s)- \mathcal{L} u(\mathbf{z} , t; s)= 0, $ where $ \mathcal{L} $ is the sub-Laplacian on the Heisenberg group. Assume that the initial data $f$ satisfies $\vert f(\mathbf{z} , t)\vert \lesssim {q}_{\alpha } (\mathbf{z} , t), $ where ${q}_{s} $ is the heat kernel associated to $ \mathcal{L} . $ If in addition $\vert u(\mathbf{z} , t; {s}_{0} )\vert \lesssim {q}_{\beta } (\mathbf{z} , t), $ for some ${s}_{0} \in \mathbb{R} \setminus \{ 0\} , $ then we prove that $u(\mathbf{z} , t; s)= 0$ for all $s\in \mathbb{R} $ whenever $\alpha \beta \lt { s}_{0}^{2} . $ This result holds true in the more general context of $H$-type groups. We also prove an analogous result for the Grushin operator on ${ \mathbb{R} }^{n+ 1} . $

Rough estimates on the scalar heat kernel

2011 ◽  
Author(s):  
Jean-Michel Bismut
Keyword(s):  
Wave Equation ◽  
Heat Equation ◽  
Heat Kernel ◽  
Heat Kernels ◽  
Hypoelliptic Operator ◽  
Uniform Bounds ◽  
Standard Heat ◽  
Probabilistic Construction

This chapter establishes rough estimates on the heat kernel rb,tX for the scalar hypoelliptic operator AbX on X defined in the preceding chapter. By rough estimates, this chapter refers to just the uniform bounds on the heat kernel. The chapter also obtains corresponding bounds for the heat kernels associated with operators AbX and another AbX over ̂X. Moreover, it gives a probabilistic construction of the heat kernels. This chapter also explains the relation of the heat equation for the hypoelliptic Laplacian on X to the wave equation on X and proves that as b → 0, the heat kernel rb,tX converges to the standard heat kernel of X.

A proof of the main identity

2011 ◽  
Author(s):  
Jean-Michel Bismut
Keyword(s):  
Heat Kernel ◽  
Heat Kernels

This chapter proves the formula that was stated in Chapter 6. It first states various estimates on the hypoelliptic heat kernels, which are valid for b ≥ 1 and then makes a natural rescaling on the coordinates parametrizing ̂X. Next, the chapter introduces a conjugation on the Clifford variables and shows that the norm of the term defining the conjugation can be adequately controlled. The chapter then introduces a conjugate ℒA,bX of another ℒA,bX and its associated heat kernel. Afterward, the chapter obtains the limit as b → +∞ of the rescaled heat kernel, thus establishing the formula in Chapter 6. After further computations, this chapter states a result on convergence of heat kernels.

Heat Kernels of Lorentz Cones

1999 ◽  
Vol 42 (2) ◽  
pp. 169-173 ◽  
Author(s):  
Hongming Ding
Keyword(s):  
Heat Kernel ◽  
Explicit Formula ◽  
Lower Bounds ◽  
Heat Kernels ◽  
Upper And Lower Bounds ◽  
Symmetric Cones ◽  
Lorentz Cone

AbstractWe obtain an explicit formula for heat kernels of Lorentz cones, a family of classical symmetric cones. By this formula, the heat kernel of a Lorentz cone is expressed by a function of time t and two eigenvalues of an element in the cone. We obtain also upper and lower bounds for the heat kernels of Lorentz cones.

Poisson’s integral formula via heat kernels

Analysis ◽  
2019 ◽  
Vol 39 (2) ◽  
pp. 59-64
Author(s):  
Yoichi Miyazaki
Keyword(s):  
Fourier Transform ◽  
Heat Kernel ◽  
Half Space ◽  
Unbounded Domain ◽  
Harmonic Functions ◽  
Integral Formula ◽  
Heat Kernels ◽  
Transform Method ◽  
Fourier Transform Method ◽  
The Fourier Transform

Abstract We give another proof of Poisson’s integral formula for harmonic functions in a ball or a half space by using heat kernels with Green’s formula. We wish to emphasize that this method works well even for a half space, which is an unbounded domain; the functions involved are integrable, since the heat kernel decays rapidly. This method needs no trick such as the subordination identity, which is indispensable when applying the Fourier transform method for a half space.

scholarly journals Exponential coordinates and regularity of groupoid heat kernels

2014 ◽  
Vol 12 (2) ◽  
Author(s):  
Bing So
Keyword(s):  
Differential Operator ◽  
Heat Kernel ◽  
Heat Kernels ◽  
Pseudo Differential Operator

AbstractWe prove that on an asymptotically Euclidean boundary groupoid, the heat kernel of the Laplacian is a smooth groupoid pseudo-differential operator.

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