Bettelheim E, Abanov A G, Wiegmann P
James Frank Institute, University of Chicago, 5640 S. Ellis Ave., Chicago, Illinois 60637, USA.
Phys Rev Lett. 2006 Dec 15;97(24):246402. doi: 10.1103/PhysRevLett.97.246402.
A semiclassical wave packet propagating in a dissipationless Fermi gas inevitably enters a "gradient catastrophe" regime, where an initially smooth front develops large gradients and undergoes a dramatic shock-wave phenomenon. The nonlinear effects in electronic transport are due to the curvature of the electronic spectrum at the Fermi surface. They can be probed by a sudden switching of a local potential. In equilibrium, this process produces a large number of particle-hole pairs, a phenomenon closely related to the orthogonality catastrophe. We study a generalization of this phenomenon to the nonequilibrium regime and show how the orthogonality catastrophe cures the gradient catastrophe, by providing a dispersive regularization mechanism.
在无耗散费米气体中传播的半经典波包不可避免地会进入“梯度灾难”状态，即初始平滑的前沿会产生大梯度并经历剧烈的冲击波现象。电子输运中的非线性效应源于费米面处电子能谱的曲率。它们可以通过局部势的突然切换来探测。在平衡状态下，这个过程会产生大量的粒子 - 空穴对，这一现象与正交灾难密切相关。我们研究了这种现象在非平衡态的推广，并展示了正交灾难如何通过提供一种色散正则化机制来消除梯度灾难。
