Quantum lamb model

Presenter's Name(s)

Nam Dinh

Abstract

Horace Lamb considered the classical dynamics of a vibrating particle embedded in an elastic medium before the development of quantum theory. Lamb was interested in how the back-action of the elastic waves generated can damp the vibrations of the particle. We propose a quantum version of Lamb’s model. We show that this model is exactly solvable by using a multimode Bogoliubov transformation. We show that the exact system ground state is a multimode squeezed vacuum state, and we obtain the exact Bogoliubov frequencies by numerically solving a nonlinear integral equation. A closed-form expression for the damping rate of the particle is obtained, and we find that it agrees with the result obtained by perturbation theory for coupling strengths below a critical value. The model is found to break down for coupling strength above the critical value where the lowest Bogoliubov frequency vanishes. We show that the addition of an anharmonic elastic term is sufficient to stabilize the system in this strong coupling regime.

Primary Faculty Mentor Name

Dennis Clougherty

Status

Graduate

Student College

College of Engineering and Mathematical Sciences

Program/Major

Physics

Primary Research Category

Physical Science

Abstract only.

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Quantum lamb model

Horace Lamb considered the classical dynamics of a vibrating particle embedded in an elastic medium before the development of quantum theory. Lamb was interested in how the back-action of the elastic waves generated can damp the vibrations of the particle. We propose a quantum version of Lamb’s model. We show that this model is exactly solvable by using a multimode Bogoliubov transformation. We show that the exact system ground state is a multimode squeezed vacuum state, and we obtain the exact Bogoliubov frequencies by numerically solving a nonlinear integral equation. A closed-form expression for the damping rate of the particle is obtained, and we find that it agrees with the result obtained by perturbation theory for coupling strengths below a critical value. The model is found to break down for coupling strength above the critical value where the lowest Bogoliubov frequency vanishes. We show that the addition of an anharmonic elastic term is sufficient to stabilize the system in this strong coupling regime.