本論文主要是討論一個一維且有交互作用（interaction）的系統在一個雜質的微擾下（weak barrier），其所表現出來的物理現象。我們使用路徑積分求得雜質部分的effective action，然後使用effective action來算出系統在沒有雜質時候的電流。再使用influence functional的技巧來求得有雜質的時候，電導的修正。最後我們得到其電導的特性和施予的偏壓有關。當偏壓極小的時候，電導為一常數；當偏壓超過某一個範圍時，電導變成為一個和偏壓的次方有關的函數。

We study the transport phenomenon in a one-dimensional system of interacting electrons with a single weak barrier. We calculate the effective action for the impurity part by path integral, then using effective action to calculate the conductance of the system without any impurity. Influence functional is then used to include the system-environment interaction, so we can calculate the effect caused by the single weak impurity. The result shows that the conductance has different dependences depending on the relation between applied voltage and temperature. When bias is small, conductance becomes a constant; when bias is large, conductance has a power dependence on voltage.

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