How nonlinearity distorts the evidence for photoinduced superconductivity

We have recently identified a fundamental flaw in the analysis of several influential results on photoinduced superconductivity in K₃C₆₀. We have also shown that similar measurements on other compounds suffer from the same problem. I will show how this systematic error distorts the existing evidence for both photoinduced superconductivity and Higgs-mediated terahertz amplification in K₃C₆₀. When we account for this error, we find that the experiments on K₃C₆₀ may be understood instead as a photoenhancement of its carrier mobility that saturates with fluence, with no need to appeal to a photoinduced phase transition to a superconducting state. I will describe how this error also distorts the evidence for photoinduced superconductivity in the normal state of cuprate superconductors and the charge-transfer salt BEDT-TTF. Finally, I will describe how recent work on K₃C₆₀ provides quantitative support for our analysis.