Quantum Mechanics: Coupled Electric Harmonic Oscillators

In summary, the conversation is about analyzing the system of two electric harmonic oscillations with frequencies \omega_{1} and \omega_{2} at a distance R and a coupling constant \gamma quantum mechanically. The equations of motion and the Hamiltonian for the system are given, and the main question is whether the Hamiltonian can be substituted into Schrödinger's equation. It is also mentioned that the problem can be solved by finding the normal modes and quantizing them as harmonic oscillators.
  • #1
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Hi

I am doing this completely out of self interest and it is not my homework to do this.
I hope somebody can help me.

Homework Statement


In the book Biological Coherence and Response to External Stimuli Herbert Fröhlich wrote a chapter on Resonance Interaction. Where he considers the interaction of two electric harmonic oscillations with frequencies [itex]\omega_{1}[/itex] and [itex]\omega_{2}[/itex]at a distance R with a coupling constant [itex]\gamma[/itex] which is proportional to [itex]\frac{1}{R^{3}}[/itex].
I want to analyze this system quantum mechanically.


Homework Equations



The equations of motions are

[itex]\ddot{q_1}+\omega_{1}^2 q_{1}=-\gamma q_{2}[/itex]

[itex]\ddot{q_2}+\omega_{1}^2 q_{2}=-\gamma q_{1}[/itex]

The Hamiltonian is given by

[itex]H=\frac{1}{2}(\dot{q_1}^2+\omega_{1}^2 q_{1}^2)+\frac{1}{2}(\dot{q_2}^2+\omega_{2}^2 q_{2}^2)+\gamma q_{1}q_{2}[/itex]

The Attempt at a Solution



For a start we know Schrödinger's Equation:

[itex]i \overline{h} \frac{\partial \Psi}{\partial t}=H\Psi[/itex]

My problem is: Can I substitute the Hamiltonian into Schrödingers Equation?
Because q1 and q2 are charges, aren't they?
 
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  • #2
The variables ##q_{1}## and ##q_{2}## are not charges, they are position coordinates of particles. The hamiltonian should be a function of canonical momenta ##p_{i}=\frac{\partial L}{\partial \overset{.}{q}_{i}}## and position coordinates ##q_{i}##, not a function of ##\overset{.}{q}_{i}## and ##q_{i}##. In this case, however it does not matter because here ##p_{i} = \overset{.}{q}_{i}##.

To solve the problem, you first find the normal modes of the oscillation. You don't need any reference to quantum mechanics to do this. Then when you know the normal modes and can decouple the equations, you can quantize the modes as harmonic oscillators, changing classical position and momentum variables to corresponding operators.
 

Related to Quantum Mechanics: Coupled Electric Harmonic Oscillators

1. What is a coupled electric harmonic oscillator in quantum mechanics?

A coupled electric harmonic oscillator refers to a system of two or more electrically charged particles that are connected through a harmonic potential. This means that the particles are attracted to each other and behave like springs, with an equilibrium distance between them. In quantum mechanics, this system is described using mathematical equations and principles to understand the behavior of the particles.

2. How are the particles in a coupled electric harmonic oscillator related to each other?

The particles in a coupled electric harmonic oscillator are related through their positions and charges. They interact with each other through the electric force, which causes them to oscillate around an equilibrium position. As one particle moves, it affects the position and movement of the other particle, creating a coupled system.

3. What is the significance of quantum mechanics in studying coupled electric harmonic oscillators?

Quantum mechanics is essential in studying coupled electric harmonic oscillators because it provides a framework for understanding the behavior of these particles on a microscopic level. The principles of quantum mechanics, such as superposition and uncertainty, are necessary for predicting the behavior of the particles and their interactions with each other.

4. Can the behavior of coupled electric harmonic oscillators be accurately predicted?

Yes, the behavior of coupled electric harmonic oscillators can be accurately predicted using mathematical equations derived from quantum mechanics. These equations take into account the positions, charges, and interactions of the particles, allowing for precise predictions of their behavior over time.

5. How are coupled electric harmonic oscillators different from other quantum systems?

Coupled electric harmonic oscillators are different from other quantum systems because they involve the interaction of multiple particles, rather than just one. This makes their behavior more complex and requires different mathematical approaches to understand and predict their behavior. Additionally, the particles in a coupled electric harmonic oscillator are related through their positions and charges, whereas other quantum systems may involve different types of interactions, such as spin or energy levels.

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