大動量有效理論(Large Momentum Effective Theory, LaMET)由季向東教授於2013年提出，解決了高懸數十年的問題：從第一性原理計算部分子分布函數。過去長久以來部分子分布函數(Parton Distribution Function)只能由實驗進行抽取。部分子分布函數為研究核子內部結構非常重要的物理量，對於各類高能實驗及模擬都是不可或缺的輸入之一。通過大動量有效理論，部分子分布函數可以經由格點場論進行第一性原理計算，不只能和實驗互相驗證，更能彌補實驗上極難測量的參數區域。此理論為目前量子色動力學及核物理領域最前沿的研究方向之一。

In 2013, Prof. Xiangdong Ji proposed Large Momentum Effective Theory (LaMET) to tackle a fundamental problem which remains unsolved for decades: Calculate the Parton Distribution Function (PDF) from the first principle. Since the birth of QCD, PDFs can only be extracted by experiments. It is an important physical quantity for studying the internal structure of the nucleus as well as an indispensable input for the high energy experiments. Through the large momentum effective theory, PDFs can be calculated from the first principle using lattice field theory. This allows us to not only verify the extracted PDFs from experiments, but also access the parameter space which is extremely difficult to measure in experiments. The theory is one of the most cutting-edge research in the field of nuclear physics.