Closed-System Solution of the 1D Atom from Collision Model

TL;DR

This paper presents a collision model approach to exactly solve the wavefunction evolution of a 1D atom interacting with a quantum field, enabling detailed analysis of entanglement and dynamics in quantum systems.

Contribution

It introduces a collision model method to obtain the total wavefunction of a 1D atom-field system, applicable to various initial field states, advancing understanding of quantum dynamics.

Findings

Exact wavefunction solutions for the atom-field system

Applicable to coherent and single-photon initial states

Provides insights into entanglement and quantum energetics

Abstract

Obtaining the total wavefunction evolution of interacting quantum systems provides access to important properties, such as entanglement, shedding light on fundamental aspects, e.g. quantum energetics and thermodynamics, and guiding towards possible application in the fields of quantum computation and communication. We consider a two-level atom (qubit) coupled to the continuum of travelling modes of a field confined in a one-dimensional waveguide. Originally, we treat the light-matter ensemble as a closed, isolated system. We solve its dynamics using a collision model where individual temporal modes of the field locally interact with the qubit in a sequential fashion. This approach allows us to obtain the total wavefunction of the qubit-field system, at any time, when the field starts in a coherent or a single-photon state. Our method is general and can be applied to other initial field states.