An experiment on multiple pathway quantum interference for the advanced undergraduate physics laboratory

TL;DR

This paper details an undergraduate physics lab experiment exploring multiple-path quantum interference using cesium atoms, demonstrating how interference affects transition amplitudes and providing a practical, educational approach to complex atomic physics concepts.

Contribution

It introduces a feasible experimental setup for undergraduates to study quantum interference effects in atomic transitions, combining experimental and theoretical analysis.

Findings

Strong spectral variation due to interfering amplitudes observed

Hyperfine component strengths determined in cesium transition

Experiment demonstrates quantum interference effects clearly

Abstract

We present results on a multiple-optical-path quantum interference project suitable for the advanced undergraduate laboratory. The experiments combine a conceptually rich set of atomic physics experiments which may be economically developed at a technical level accessible to undergraduate physics or engineering majors. In the experiments, diode-laser driven two-quantum, two-color excitation of cesium atoms in a vapor cell is investigated and relative strengths of the individual hyperfine components in the $6s^{2}S_{1/2} \rightarrow 7s^{2}S_{1/2}$ transition are determined. Measurement and analysis of the spectral variation of the two quantum excitation rate clearly shows strong variations due to interfering amplitudes in the overall transition amplitude. Projects such as the one reported here allow small teams of undergraduate students with combined interests in experimental and theoretical physics to construct instrumentation, perform sophisticated experiments, and do realistic modelling of the results.