Acoustic analog to multiple avoided-crossings in two coupled acoustic cavities

Abstract

A closed cylindrical pipe with an inner partition wall forms two one-dimensional cavities. These each exhibit acoustic modes at certain well-defined frequencies. A partial transmission through the partition leads to interactions between the two cavities' modes, and hence to avoided crossings between modes' frequencies. This acoustic system is analogous to a quantum system that has two multi-level interacting sub-systems and, thus, exhibits multiple avoided crossings. Such an acoustic analog is realized and studied by measuring sound transmission as a function of frequency through a pipe with a partially transmitting and movable partition. An excellent agreement is obtained between the experimental results and a simple model based on wave transmission and reflection at different interfaces.