Room temperature superconductivity ?

Comment on Nature 586, 373 (2020) by E. Snider et al ; Dirk van der Marel & Jorge E Hirsch ; arXiv:2201.07686 (2022)

Illustration of the correlation analysis in arXiv:2201.07686

Left: If the two signals “measured voltage” (MV) and “background signal” (BG) are mutually independent, the function ΣiΔnMViΔnBGi+j describing the correlation between these two signals (shorthand notation: nm;Δnb>j) reveals only random noise. Here i labels the ith temperature Ti, and Δn is the nth discrete derivative (see Eq. 7 of arXiv:2201.07686). The background corrected signal SC = MVBG (“superconducting signal”) is necessarily correlated both with MV and with BG. For ns;Δnm>j this is revealed as a peak and for ns;Δnb>j as a dip, both at j=0.

Right: The superconducting signal data reported in Nature 586, 373 (2020) are not compatible with the notion that SC was obtained by subtracting BG from raw MV data. It is compatible with the reverse protocol where BG and SC were obtained independently, causing them to be uncorrelated, and where MV was obtained by adding BG to SC. It clashes with the assumption that MV is raw data.
NB: SC, MV and BG are correlated in the same way for all other pressures as for the example of 160 GPa shown here.

Incompatibility of published ac magnetic susceptibility of a room temperature superconductor with measured raw data ; J. E. Hirsch & D. van der Marel;
Matter and Radiation at Extremes 7, 048401 (2022), DOI:10.1063/5.0088429;

« User Defined Background ». The authors of Nature 586, 373 (2020) provide various different accounts of “the making of” the susceptibility data.

Room temperature superconductivity – or not ?
Flatclub seminar, University of Geneva, 29 April 2022.
Video (mp4)Slides (pptx)Slides (pdf).

Room temperature superconductivity – or not ?
Colloquium at city University of Hongkong, 7 June 2022.
Video (mp4)Slides (pptx)Slides (pdf).