Abstract

Let H:=−12Δ+V be a one-dimensional continuum Schrödinger operator. Consider Hˆ:=H+ξ, where ξ is a translation invariant Gaussian noise. Under some assumptions on ξ, we prove that if V is locally integrable, bounded below, and grows faster than log at infinity, then the semigroup e−tHˆ is trace class and admits a probabilistic representation via a Feynman-Kac formula. Our result applies to operators acting on the whole line R, the half line (0,∞), or a bounded interval (0,b), with a variety of boundary conditions. Our method of proof consists of a comprehensive generalization of techniques recently developed in the random matrix theory literature to tackle this problem in the special case where Hˆ is the stochastic Airy operator.

Highlights

  • Let I ⊂ R be an open interval and V : I → R be a function.denote a Schrödinger operator with potential V acting on functions f : I → R with prescribed boundary conditions when I has a boundary

  • Provided the potentials under consideration are sufficiently well behaved, there is a remarkable connection between Schrödinger semigroups and the theory of stochastic processes that can be expressed in the form of the Feynman-Kac formula (e.g., [41, Theorem A.2.7]): Assuming I = R for simplicity, for every f ∈ L2(R), t > 0, and x ∈ R, one has t e−tH f (x) = Ex exp − V B(s) ds f B(t) where B is a Brownian motion and Ex signifies that we are taking the expected value with respect to B conditioned on the starting point B(0) = x

  • Our purpose in this paper is to lay out the foundations of a general semigroup theory for random Schrödinger operators of the form (1.1)

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Summary

Introduction

Let I ⊂ R be an open interval (possibly unbounded) and V : I → R be a function. denote a Schrödinger operator with potential V acting on functions f : I → R with prescribed boundary conditions when I has a boundary. Semigroups for 1D Schrödinger operators with Gaussian noise distribution, i.e., a centered Gaussian process on an appropriate function space with covariance. Provided the potentials under consideration are sufficiently well behaved, there is a remarkable connection between Schrödinger semigroups and the theory of stochastic processes that can be expressed in the form of the Feynman-Kac formula (e.g., [41, Theorem A.2.7]): Assuming I = R for simplicity, for every f ∈ L2(R), t > 0, and x ∈ R, one has t e−tH f (x) = Ex exp − V B(s) ds f B(t). Our purpose in this paper is to lay out the foundations of a general semigroup theory (or Feynman-Kac formulas) for random Schrödinger operators of the form (1.1). Since we consider very irregular noises (i.e., in general ξ is not a proper function that can be evaluated at points in R), this undertaking is not a direct application or a trivial extension of the classical theory; see Section 1.1 for more details.

Overview of results
The Anderson Hamiltonian and parabolic Anderson model
Operator limits of random matrices
Number rigidity in random Schrödinger operators
Main results
Semigroup
Preliminary definitions
Main result
Optimality of potential growth
Examples
Proof outline
Feynman-Kac formula for deterministic operators
Reflected Brownian motion couplings
Half-line
Bounded interval
Compactness properties of deterministic kernels
A Measurability of kernel
B Tails of Gaussian suprema
C Schrödinger operator theory
Full Text
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