CM In the literature: contested

Do strange metals carry current in electron-like quasiparticles

In plain words

Shot noise, the current fluctuation caused by charge arriving in discrete packets, reveals whether current is carried by electron-like particles; in one strange metal the noise was far smaller than expected.

Precise statement

Measure the Fano factor $F = S_I/(2 e I)$ in mesoscopic wires of strange metals in the $T$-linear regime and determine whether suppression of $F$ below the Fermi-liquid values ($1/3$ for elastic diffusive transport, $\sqrt{3}/4$ for hot electrons) reflects the absence of quasiparticles or electron-phonon energy relaxation. An answer is a cross-material data set with independently measured electron-phonon length plus a theory of shot noise without quasiparticles that matches it.

What would settle it

Length- and temperature-dependent shot-noise measurements in at least two strange-metal families with control wires of a conventional metal in the same geometry.

Status in the literature

Strongly suppressed shot noise was reported in YbRh2Si2 nanowires in 2023; whether electron-phonon relaxation can explain it is debated.