Population transfer at exceptional points in spectra of the hydrogen atom in parallel electric and magnetic fields

TL;DR

This paper investigates how to optimize population transfer between resonance states in a hydrogen atom subjected to electric and magnetic fields by exploring parameter loops around exceptional points, and introduces a simplified approximation method.

Contribution

It analyzes the effect of loop shape and duration on population transfer and proposes a 2x2 matrix approximation for efficient quantum dynamics modeling.

Findings

Optimal loop parameters enhance population transfer efficiency

The 2x2 matrix approximation closely matches full quantum dynamics results

Shape and duration of parameter loops significantly influence transfer success

Abstract

We study the population transfer between resonance states for a time-dependent loop around exceptional points in spectra of the hydrogen atom in parallel electric and magnetic fields. Exceptional points are well-suited for population transfer mechanisms, since a closed loop around these in parameter space commutes eigenstates. We address the question how shape and duration of the dynamical parameter loop affects the transferred population, in order to optimize the latter. Since the full quantum dynamics of the expansion coefficients is time-consuming, we furthermore present an approximation method, based on a $2\times 2$ matrix.