Department of Physics & Astronomy, University of British Columbia, Vancouver, Canada.
Phys Rev Lett. 2011 Aug 12;107(7):076403. doi: 10.1103/PhysRevLett.107.076403. Epub 2011 Aug 9.
The momentum average approximation is used to derive a new kind of nonperturbational analytical expression for the optical conductivity (OC) of a Holstein polaron at zero temperature. This provides insight into the shape of the OC, by linking it to the structure of the polaron's phonon cloud. Our method works in any dimension, properly enforces selection rules, can be systematically improved, and also generalizes to momentum-dependent couplings. Its accuracy is demonstrated by a comparison with the first detailed set of three-dimensional numerical OC results, obtained using the approximation-free diagrammatic Monte Carlo method.
动理学平均近似法被用于推导零温下极化子光学导率（OC）的一种新型非微扰解析表达式。该方法通过将 OC 的形状与极化子的声子云结构联系起来，提供了对 OC 形状的深入了解。我们的方法适用于任何维度，正确实施选择规则，可以系统地改进，并推广到依赖动量的耦合。通过与使用无近似图蒙特卡罗方法获得的第一组详细的三维数值 OC 结果进行比较，验证了其准确性。
