Investigations of dressed quasiparticles

在固体中运动的电子与固体的所有基本激发密切相关，因此它在移动时拖着一团各种可能的激发云。这种复杂的实体被称为“修饰过的准粒子”。与原始电子相比，随着有效质量的增加，它的色散发生了变化，其光谱函数(例如通过光电发射测量)分离为相干部分和非相干部分。在某些情况下，药衣是如此强烈，以至于它可能根本不跟随粒子的运动，导致完全不相干的传播和传统的费米液体理论的崩溃。正是对这些经过修饰的准粒子及其对固体物理性质的影响的理解，推动了理论凝聚态物理的发展。

An electron moving through a solid is intimately connected with all the elementary excitations of the solid, and therefore it drags along, as it moves, a cloud of various possible excitations. This complex entity is known as a "dressed quasiparticle". When compared to the original electron, it has a changed dispersion with an increased effective mass, and a separation of its spectral function, as measured for example by photo-emission, into a coherent and an incoherent part. In some cases the dressing is so strong that it may not follow the particle's motion at all, leading to completely incoherent propagation and a breakdown of the conventional Fermi-liquid theories. It is the understanding of these dressed quasiparticles and their influence on the physical properties of the solid, that drives the world of theoretical condensed matter physics.