Discrete Breathers in Nonlinear Lattices: Experimental Detection in a Josephson Array

TLDR

Discrete breathers in nonlinear lattices can exist over a range of dc current biases and temperatures and are detected by measuring dc voltages. This experimental study investigates discrete breathers in an underdamped Josephson‑junction array. The authors examined the breather’s domain of existence by varying temperature and array parameters, detecting breathers through dc voltage measurements. The maximum bias current for a breather scales with the array depinning current, while the minimum current is linked to a junction retrapping mechanism that can trigger multi‑site breather states.

Abstract

We present an experimental study of discrete breathers in an underdamped Josephson-junction array. Breathers exist under a range of dc current biases and temperatures, and are detected by measuring dc voltages. We find the maximum allowable bias current for the breather is proportional to the array depinning current while the minimum current seems to be related to a junction retrapping mechanism. We have observed that this latter instability leads to the formation of multi-site breather states in the array. We have also studied the domain of existence of the breather at different values of the array parameters by varying the temperature.