Schrödinger equations with vanishing potentials involving Brezis-Kamin type problems (original) (raw)

Existence results for a class of quasilinear Schrödinger equations with singular or vanishing potentials

Nonlinear Analysis, 2022

Given two continuous functions V (r) ≥ 0 and K (r) > 0 (r > 0), which may be singular or vanishing at zero as well as at infinity, we study the quasilinear elliptic equation −∆w + V (|x|) w − w ∆w 2 = K(|x|)g(w) in R N , where N ≥ 3. To study this problem we apply a change of variables w = f (u), already used by several authors, and find existence results for nonnegative solutions by the application of variational methods. The main features of our results are that they do not require any compatibility between how the potentials V and K behave at the origin and at infinity, and that they essentially rely on power type estimates of the relative growth of V and K, not of the potentials separately. Our solutions satisfy a weak formulations of the above equation, but we are able to prove that they are in fact classical solutions in R N \{0}. To apply variational methods, we have to study the compactness of the embedding of a suitable function space into the sum of Lebesgue spaces L q 1 K + L q 2 K , and thus into L q K (= L q K + L q K) as a particular case. The nonlinearity g has a double-power behavior, whose standard example is g(t) = min{t q 1 −1 , t q 2 −1 }, recovering the usual case of a single-power behavior when q1 = q2.

Bound state solutions of sublinear Schrödinger equations with lack of compactness

Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A. Matemáticas

We consider the following nonlinear Schrödinger equation − u + V (x)u = a(x) |u| q−1 u + f (x), x ∈ R N , where V is a non-symmetric bounded potential, a is an indefinite weight, 0 < q < 1 and f = 0 is a nonnegative perturbation such that f ∈ L 2 (R N) ∩ L 2N N +2 (R N). Using variational methods, we prove the existence of two solutions with negative and positive energies, one of these solutions being nonnegative.

Existence of weak solutions to some stationary Schrödinger equations with singular nonlinearity

We prove some existence (and sometimes also uniqueness) of solutions to some stationary equations associated to the complex Schrödinger operator under the presence of a singular nonlinear term. Among other new facts, with respect some previous results in the literature for such type of nonlinear potential terms, we include the case in which the spatial domain is possibly unbounded (something which is connected with some previous localization results by the authors), the presence of possible non-local terms at the equation, the case of boundary conditions different to the Dirichlet ones and, finally, the proof of the existence of solutions when the right-hand side term of the equation is beyond the usual L 2-space.

Positive Solutions for a Quasilinear Schrödinger Equation with Critical Growth

Journal of Dynamics and Differential Equations, 2011

We consider the quasilinear problem −ε p div(|∇u| p−2 ∇u) + V (z)u p−1 = f (u) + u p * −1 , u ∈ W 1,p (R N), where ε > 0 is a small parameter, 1 < p < N , p * = N p/(N − p), V is a positive potential and f is a superlinear function. Under a local condition for V we relate the number of positive solutions with the topology of the set where V attains its minimum. In the proof we apply Ljusternik-Schnirelmann theory.

About existence and regularity of positive solutions for a quasilinear Schrödinger equation with singular nonlinearity

Electronic Journal of Qualitative Theory of Differential Equations, 2020

We establish the existence of positive solutions for the singular quasilinear Schrödinger equation −∆u − ∆(u 2)u = h(x)u −γ + f (x, u) in Ω, u(x) = 0 on ∂Ω, where Ω ⊂ R N (N ≥ 3) is a bounded domain with smooth boundary ∂Ω, 1 < γ, h ∈ L 1 (Ω) and h > 0 almost everywhere in Ω. The function f may change sign on Ω. By using the variational method and some analysis techniques, the necessary and sufficient condition for the existence of a solution is obtained.

Multiple Positive Solutions to Nonlinear Schrödinger Equations with Competing Potential Functions

Journal of Differential Equations, 2000

We consider singularly perturbed nonlinear Schrödinger equations −ε 2 ∆u + V (x)u = f (u), u > 0, v ∈ H 1 (R N) (0.1) where V ∈ C(R N , R) and f is a nonlinear term which satisfies the so-called Berestycki-Lions conditions. We assume that there exists a bounded domain Ω ⊂ R N such that m 0 ≡ inf x∈Ω V (x) < inf x∈∂Ω V (x) and we set K = {x ∈ Ω | V (x) = m 0 }. For ε > 0 small we prove the existence of at least cupl(K) + 1 solutions to (0.1) concentrating, as ε → 0 around K. We remark that, under our assumptions of f , the search of solutions to (0.1) cannot be reduced to the study of the critical points of a functional restricted to a Nehari manifold.

A note on quasilinear Schrödinger equations with singular or vanishing radial potentials

Differential and Integral Equations

In this note we complete the study of [3], where we got existence results for the quasilinear elliptic equation −∆w + V (|x|) w − w ∆w 2 = K(|x|)g(w) in R N , with singular or vanishing continuous radial potentials V (r), K(r). In [3] we assumed, for technical reasons, that K(r) was vanishing as r → 0, while in the present paper we remove this obstruction. To face the problem we apply a suitable change of variables w = f (u) and we find existence of non negative solutions by the application of variational methods. Our solutions satisfy a weak formulations of the above equation, but they are in fact classical solutions in R N \ {0}. The nonlinearity g has a double-power behavior, whose standard example is g(t) = min{t q 1 −1 , t q 2 −1 } (t > 0), recovering the usual case of a singlepower behavior when q1 = q2.

Existence theorems for degenerate Schrödinger equations involving a singular potential and an indefinite sign perturbation

Annals of the University of Craiova - Mathematics and Computer Science Series, 2019

We study a degenerate quasilinear problem involving a singular potential and some bounded weights. The equation is perturbed by a critical nonlinear term and an indefinite sign perturbation involving a real parameter. Under suitable assumptions on the potentials and on the real parameter we use two different critical point techniques, in order to reveal two types of solutions. The proofs rely on variational arguments based on the Mountain-Pass Theorem, Ekeland's Variational Principle and energy estimates.