Quasi-bound states in continuum

TL;DR

This paper predicts the existence of long-lived quasi-bound states in a quantum wire with two channels and an adatom, occurring within the continuum of propagating states when energy bands overlap.

Contribution

It introduces the concept of quasi-bound states in continuum (QBIC) in a quantum wire system, highlighting their formation due to band overlap and their long lifetimes.

Findings

Quasi-bound states occur in the continuum of propagating states.

These states have very long lifetimes due to slight destabilization.

The phenomenon is demonstrated in a two-channel quantum wire with an adatom.

Abstract

We report the prediction of quasi-bound states (resonant states with very long lifetimes) that occur in the eigenvalue continuum of propagating states for a wide region of parameter space. These quasi-bound states are generated in a quantum wire with two channels and an adatom, when the energy bands of the two channels overlap. A would-be bound state that lays just below the upper energy band is slightly destabilized by the lower energy band and thereby becomes a resonant state with a very long lifetime (a second QBIC lays above the lower energy band).