#### Advisor(s)

Mellita Caragiu, PhD

Ohio Northern University

Physics & Astronomy, Science, Technology, and Mathematics

m-caragiu@onu.edu

#### Document Type

Poster

#### Location

ONU McIntosh Center; Activities Room

#### Start Date

22-4-2022 10:00 AM

#### End Date

22-4-2022 11:00 AM

#### Abstract

With the development of new instrumentation and new discoveries about atomic systems in the 1920s, it became clear very rapidly that classical (Newtonian) mechanics was insufficient to describe the results that were observed. The proposal that both matter and light existed as both a particle and wave required quantum mechanics to be developed to accurately describe those microscopic systems. However, as with other areas of physics, the correspondence principle must be followed as it is known that Newtonian mechanics works in macroscopic systems. This project investigates how the correspondence principle is followed at the transition from microscopic systems to macroscopic systems for the harmonic oscillator. Through study of Ehrenfest’s Theorem, the steps that need to be taken to transition from stationary states to a classical mechanics result are determined such that the result is equivalent when started from either mechanics theory.

#### Recommended Citation

Dunn, Timothy, "Toward Understanding the Transition Between Quantum Mechanics and Classical Mechanics" (2022). *ONU Student Research Colloquium*. 49.

https://digitalcommons.onu.edu/student_research_colloquium/2022/posters/49

#### Restricted

Available to ONU community *via* local IP address and ONU login.

Toward Understanding the Transition Between Quantum Mechanics and Classical Mechanics

ONU McIntosh Center; Activities Room

With the development of new instrumentation and new discoveries about atomic systems in the 1920s, it became clear very rapidly that classical (Newtonian) mechanics was insufficient to describe the results that were observed. The proposal that both matter and light existed as both a particle and wave required quantum mechanics to be developed to accurately describe those microscopic systems. However, as with other areas of physics, the correspondence principle must be followed as it is known that Newtonian mechanics works in macroscopic systems. This project investigates how the correspondence principle is followed at the transition from microscopic systems to macroscopic systems for the harmonic oscillator. Through study of Ehrenfest’s Theorem, the steps that need to be taken to transition from stationary states to a classical mechanics result are determined such that the result is equivalent when started from either mechanics theory.