Category: Physics

Summary: Testing whether anomalous heat transport in one-dimensional FPU-beta chains crosses over between competing exponent predictions as system size and nonlinearity vary.

Heat conduction in one-dimensional nonlinear chains is expected to violate ordinary diffusion, but the exact scaling exponent remains debated. This experiment asks whether the effective conductivity exponent in FPU-beta chains crosses over from roughly one-third at modest sizes toward two-fifths at larger sizes, and whether that crossover depends systematically on the nonlinearity strength.

The simulation runs nonequilibrium molecular dynamics with Langevin thermostats at the chain ends and GPU-parallelized time integration. From the steady-state heat flux it computes thermal conductivity and tracks how the inferred scaling exponent changes with chain length and beta.

That makes the project a crossover-mapping study rather than a single-exponent measurement. Its value is in testing whether apparently conflicting predictions are actually different parts of one finite-size scaling picture.

Method: GPU-parallelized nonequilibrium molecular dynamics of FPU-beta chains with Langevin baths, measuring heat flux and conductivity scaling with system size.

What is measured: Thermal conductivity, effective transport exponent alpha, crossover curves versus system size, and dependence on nonlinearity strength beta.