what does this theory state?
It states that pattern of motion typically consists of random fluctuations in a particle's position inside a fluid sub-domain, followed by a relocation to another sub-domain.
Brownian motion
Brownian motion, or pedesis (from "leaping"), is the random motion of particles suspended in a medium (a liquid or a gas).

This pattern of motion typically consists of random fluctuations in a particle's position inside a fluid sub-domain, followed by a relocation to another sub-domain. Each relocation is followed by more fluctuations within the new closed volume. 
who came up with the theory of continuous matter Albert Einstein are there any other scientists or physicists associated with the theory mentioned? Yes, Robert Brown. any theories named after him? Yes, the "Brownian Motion".
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Brownian motion [SEP] Introduction
This motion is named after the botanist Robert Brown, who first described the phenomenon in 1827, while looking through a microscope at pollen of the plant "Clarkia pulchella" immersed in water. In 1905, almost eighty years later, theoretical physicist Albert Einstein published a paper where he modeled the motion of the pollen particles as being moved by individual water molecules, making one of his first major scientific contributions. This explanation of Brownian motion served as convincing evidence that atoms and molecules exist and was further verified experimentally by Jean Perrin in 1908. Perrin was awarded the Nobel Prize in Physics in 1926 "for his work on the discontinuous structure of matter".