Date of Completion

2023

Document Type

Honors College Thesis

Department

Physics

Thesis Type

Honors College

First Advisor

Dr. Dennis Clougherty

Keywords

quantum sticking, entanglement entropy, adsorption, cold-atom

Abstract

An incident particle is drawn towards a neutral solid because of van der Waals attraction. When it collides, some of its energy goes to exciting vibrations of the solid. As a result of the collision, the particle could be adsorbed by the solid, or it could be scattered off the solid. The purpose of this thesis is to study the dynamics of a slow-moving, cold atom that collides with a two-dimensional solid, such as a hydrogen atom colliding with graphene. Using a time-dependent ansatz for the system wave function, we obtained coupled time-dependent equations that describe the possible outcomes of the collision. From these equations, the adsorption, or sticking, of the atom on a surface is studied. The numerical calculation shows for the case of N vibrational modes, the transition probability exhibits Rabi flopping. However, when the vibrons have a finite lifetime, the oscillations of the transition probability damp over time. From the calculations, the time dependent entanglement entropy (von Neumann entropy), S(t), is subsequently studied. The entanglement entropy grows from zero to a local maximum and then falls to zero. At a later time, the calculations show ``quantum revival'' where the entanglement entropy again grows to a local maximum and subsequently collapses to zero. These results are discussed and interpreted in terms of the quantum sticking process.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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