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Anderson localized states for the nonlinear Maryland model on $\mathbb{Z}^d$

Shihe Liu, Yunfeng Shi, Zhifei Zhang

TL;DR

This work addresses nonlinear Anderson localization for a Maryland quasi-periodic model on $\mathbb{Z}^d$ by diagonalizing the linear Maryland operator and applying a Craig–Wayne–Bourgain (CWB) framework. The authors construct time-quasi-periodic, spatially exponentially decaying localized states for the nonlinear Schrödinger equation $i\partial_t u=Hu+\delta|u|^{2p}u$ in the regime of small $\varepsilon$ and $\delta$ with Diophantine frequency $\alpha$, starting from a finite set of localized linear eigenfunctions. Key contributions include a large deviation theorem for Green's functions across multiple scales, precise eigenvalue separation estimates for the unbounded Maryland potential, and a nonlinear Lyapunov–Schmidt/Nash–Moser scheme that yields quasi-periodic localized solutions with frequencies near the linear eigenvalues. This work extends Anderson localization to nonlinear Maryland-type models in higher dimensions and provides a robust analytical framework that blends spectral analysis with multi-scale probabilistic techniques, delivering both existence and quantitative decay properties of nonlinear localized states. The results have potential implications for understanding interacting quantum systems in quasi-periodic disordered media and for the broader study of nonlinear dynamics in almost-periodic settings.

Abstract

In this paper, we investigate Anderson localization for a nonlinear perturbation of the Maryland model $H=\varepsilonΔ+\cotπ(θ+j\cdotα)δ_{j,j'}$ on $\mathbb{Z}^d$. Specifically, if $\varepsilon,δ$ are sufficiently small, we construct a large number of time quasi-periodic and space exponentially decaying solutions (i.e., Anderson localized states) for the equation $i\frac{\partial u}{\partial t}=Hu+δ|u|^{2p}u$ with a Diophantine $α$. Our proof combines eigenvalue estimates of the Maryland model with the Craig-Wayne-Bourgain method, which originates from KAM theory for Hamiltonian PDEs.

Anderson localized states for the nonlinear Maryland model on $\mathbb{Z}^d$

TL;DR

This work addresses nonlinear Anderson localization for a Maryland quasi-periodic model on by diagonalizing the linear Maryland operator and applying a Craig–Wayne–Bourgain (CWB) framework. The authors construct time-quasi-periodic, spatially exponentially decaying localized states for the nonlinear Schrödinger equation in the regime of small and with Diophantine frequency , starting from a finite set of localized linear eigenfunctions. Key contributions include a large deviation theorem for Green's functions across multiple scales, precise eigenvalue separation estimates for the unbounded Maryland potential, and a nonlinear Lyapunov–Schmidt/Nash–Moser scheme that yields quasi-periodic localized solutions with frequencies near the linear eigenvalues. This work extends Anderson localization to nonlinear Maryland-type models in higher dimensions and provides a robust analytical framework that blends spectral analysis with multi-scale probabilistic techniques, delivering both existence and quantitative decay properties of nonlinear localized states. The results have potential implications for understanding interacting quantum systems in quasi-periodic disordered media and for the broader study of nonlinear dynamics in almost-periodic settings.

Abstract

In this paper, we investigate Anderson localization for a nonlinear perturbation of the Maryland model on . Specifically, if are sufficiently small, we construct a large number of time quasi-periodic and space exponentially decaying solutions (i.e., Anderson localized states) for the equation with a Diophantine . Our proof combines eigenvalue estimates of the Maryland model with the Craig-Wayne-Bourgain method, which originates from KAM theory for Hamiltonian PDEs.

Paper Structure

This paper contains 19 sections, 21 theorems, 384 equations, 2 figures.

Key Result

Theorem 1.1

Let $\alpha\in{\rm DC}_{\gamma,\tau}$ and fix any $b$ distinct lattice sites $\beta_k\in \mathbb{Z}^d,\ k=1,2,\cdots,b$ with $\sup_{k}|\beta_k|\leq B$. Define with $\mathbf{a}=(a_1,\cdots, a_k)\in [1,2]^b$. Then for $0<\delta\leq \tilde{\delta}(\gamma,\tau,b,d,B,p)\ll 1$, there exist a constant $\tilde{\varepsilon}=\tilde{\varepsilon}(\delta)>0$ and a set $\Theta=\Theta_{\alpha,\delta}\subset [0,

Figures (2)

  • Figure 1: The construction of relabelling map in each annulus.
  • Figure 2: Homothetic transform from cubes to vertices.

Theorems & Definitions (35)

  • Theorem 1.1
  • Lemma 2.1: Theorem 1.1, KPS24
  • Lemma 2.2
  • proof
  • Lemma 2.3
  • proof
  • Theorem 2.4: Separation property of eigenvalues
  • proof : Proof of Theorem $\ref{['seperative spectrum']}$
  • Lemma 2.5: cf. Lemma A.4 of SW24
  • Lemma 2.6: cf. Lemma A.5 of SW24
  • ...and 25 more