סמינר בחומר מעובה: Collective effects and possible "high temperature quantization" in supercooled metallic liquids

Abstract:

We introduce notions concerning locally preferred structures and discuss recent experimental and numerical results on metallic fluids that indicate the onset of cooperative dynamics as a liquid is supercooled to form a glass.

We will further suggest that certain quantum effects may emerge in the high temperature limit of general "classical fluids". Towards this end, we will invoke the WKB approximation, extend the usual kinetic theory by taking into account a possible minimal quantum time scale, apply ideas from transition state theory, and relate (via Planck's constant) the thermodynamic entropy to periods of semi-classical trajectories. Taken together, these will suggest that, on average, the extrapolated high temperature viscosity of general liquids may tend to a value set by the product of the particle number density n and Planck's constant h. Experimental measurements of an ensemble of 23 metallic fluids indicate that might indeed be the case; the extrapolated high temperature viscosity of each of these liquids divided (for each respective fluid) by its value of nh veers towards a Gaussian with an ensemble average value that is close to unity up to an error of size 0.6%. We invoke similar ideas to discuss other transport properties to suggest how simple behaviors may appear including resistivity saturation and linear T resistivity may appear naturally. This approach suggests that minimal time lags may be present in general fluid dynamics.

מארגן הסמינר: פרופ' שמשון ברעד