Temperature Chaos in a Spin Glass Observed using the Correlation Length as a Caliper

We have developed a protocol to observe temperature chaos in a CuMn spin glass. Specifically, temperature cycling curves were compared with a reference curve, the latter without a temperature drop. The temperature cycling curves are shifted in time to overlap the reference curve at long times for a given temperature drop. Departures from the reference curve set in at a critical temperature change, indicating temperature chaos. For larger temperature drops, the temperature cycling curves depart even further from the reference curse, suggesting enhanced chaos. The results support the Bray-Moore length scale argument that temperature chaos sets in when the chaos length equals the spin glass correlation length. To extract the chaos exponent, the spin glass correlation is used as a “caliper” for the chaos length. The extracted chaos exponent is found near unity using different approximation schemes, agreeing for the first time with previous theoretical analysis and numerical simulations. Our results also demonstrate that temperature chaos occurs under non-equilibrium conditions.