séminaire CRMQ

1. Francis Laliberté Title: “Universal T-linear resistivity and Planckian limit in overdoped cuprates” Abstract: The perfectly linear temperature dependence of the electrical resistivity observed as T → 0 in a variety of metals close to a quantum critical point is a major puzzle of condensed matter physics. In this seminar, I will show that T-linear resistivity as T → 0 is a generic property of cuprates, associated with a universal scattering rate. The slope of the T-linear resistivity (per CuO2 plane) is found to be given by h / 2e^2 times the inverse Fermi temperature. This relation is obtained by assuming that the scattering rate 1 / τ of charge carriers reaches the Planckian limit, whereby ħ / τ = k_B T. This simple empirical observation implies that there must be a fundamental and universal principle at play. 2. Jeffrey Quilliam Title: “Vitesse ultrasonore dans un liquide de spin quantique”