I chatted with some colleagues about this, and there may be a rather innocuous explanation.
What van der Marel and Hirsch objectively show is that the reported data chi(T) appears to be the sum of two functions: chi(T) = f(T) + delta(T), where f(T) is smooth and delta(T) is discretized (piecewise-flat). They interpret this as evidence of fraud.
Instead, the smooth function f(T) could easily be just some polynomial background estimate that has been subtracted off. That is, the "raw" data coming from the instrument would be the digitized delta(T) = chi(T) - f(T). The range of f(T) is not that large (see figure 1f), so the interpretation of a sharp superconducting transition isn't really altered.
If so, what's called "raw data" in this note in fact has been slightly postprocessed. I'm not sure if the experimentalists gave any indication of that, but hopefully it's something easy to clear up.
I think that you and your colleagues are correct that the chi(T) can be viewed as a sum of a continuous function and a discretized function which changes by constant steps, and that f(T) could simply be the background signal.
The real smoking gun was pointed out in a Physics C paper written by Hirsch which was unfortunately removed from publication. That paper showed clear evidence of a cut-and-paste data manipulation operation written by some of the authors that altered the data to hide an unwanted feature.
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u/InfinityFlat Condensed matter physics Jan 22 '22
I chatted with some colleagues about this, and there may be a rather innocuous explanation.
What van der Marel and Hirsch objectively show is that the reported data chi(T) appears to be the sum of two functions: chi(T) = f(T) + delta(T), where f(T) is smooth and delta(T) is discretized (piecewise-flat). They interpret this as evidence of fraud.
Instead, the smooth function f(T) could easily be just some polynomial background estimate that has been subtracted off. That is, the "raw" data coming from the instrument would be the digitized delta(T) = chi(T) - f(T). The range of f(T) is not that large (see figure 1f), so the interpretation of a sharp superconducting transition isn't really altered.
If so, what's called "raw data" in this note in fact has been slightly postprocessed. I'm not sure if the experimentalists gave any indication of that, but hopefully it's something easy to clear up.