• Corpus ID: 253238063

Quantum Systems at The Brink

@inproceedings{Hundertmark2022QuantumSA,
  title={Quantum Systems at The Brink},
  author={Dirk Hundertmark and Michal Jex and Markus Lange},
  year={2022}
}
We present a method to calculate the asymptotic behavior of eigenfunctions of Schrödinger operators that also works at the threshold of the essential spectrum. It can be viewed as a higher order correction to the well-known WKB method which does need a safety distance to the essential spectrum. We illustrate its usefulness on examples of quantum particles in a potential well with a long-range repulsive term outside the well. 

Figures from this paper

Ju l 2 02 1 Quantum Systems at The Brink Existence and Decay Rates of Bound States at Thresholds ; Critical Potentials and dimensionality

One of the crucial properties of a quantum system is the existence of bound states. In this paper we present a necessary and sufficient condition for the Schrödinger operator to have a zero energy

Coupling constant thresholds in nonrelativistic quantum mechanics

We extend the analysis of absorbtion of eigenvalues for the two body case to situations where absorbtion occurs at a two cluster threshold in anN-body system. The result depends on a Birman-Schwinger

Quantum Systems at the Brink: Existence of Bound States, Critical Potentials and Dimensionality

A BSTRACT . One of the crucial properties of a quantum system is the existence of bound states. While the existence of eigenvalues below zero, i.e., below the essential spectrum, is well understood,

A multiparticle Coulomb system with bound state at threshold

The authors consider the two-electron Hamiltonian H=- Delta 1- Delta 2-r1-1-r2-1+Ar12-1 at precisely that critical value of A where the ground state energy has just hit the continuum. For that A, it

The virtual level of the Schrödinger equation

The three-dimensional Schrödinger operator H is considered with a so-called virtual level at the start of the spectrum. The existence of a virtual level means, roughly speaking, that the

Quantum Systems at The Brink: Helium-type systems

In the present paper we study two challenging problems for helium–type systems. Existence of eigenvalues at thresholds and the asymptotic behavior of the corresponding eigenfunctions. Since the usual

Zero-Energy Bound State Decay for Non-local Schrödinger Operators

We consider solutions of the eigenvalue equation at zero energy for a class of non-local Schrödinger operators with potentials decreasing to zero at infinity. Using a path integral approach, we

Geometric methods in the quantum many-body problem. Nonexistence of very negative ions

In this paper we develop the geometric methods in the spectral theory of many-body Schrödinger operators. We give different simplified proofs of many of the basic results of the theory. We prove that

Quantum Systems at The Brink. Existence and Decay Rates of Bound States at Thresholds; Atoms

It is well known that N -electron atoms undergoes unbinding for a critical charge of the nucleus Zc, i.e. the atom has eigenstates for the case Z > Zc and it has no bound states for Z < Zc. In the

Rigorous conditions for the existence of bound states at the threshold in the two-particle case

In the framework of non-relativistic quantum mechanics and with the help of Green's functions formalism, we study the behaviour of weakly bound states in a non-central two-particle potential as they

Low energy asymptotics for Schrödinger operators with slowly decreasing potentials

Low energy behavior of Schrödinger operators with potentials which decay slowly at infinity is studied. It is shown that if the potential is positive then the zero energy is very regular and the
...