The poet ee cummings wrote, `always the more beautiful answer who asks the more beautiful question'. My question is: how are complex things made from simple things? Large molecules, such as DNA, are often more complex than the simple atoms from which they are built. An important key to understanding complexity, in my view, is correlation. My research focuses on the dynamics of electron correlation in atomic, molecular and optical physics. It is the subject of my book, "Electron Correlation Dynamics in Atomic Collisions".
`Correlation' means interdependency. Correlation is the conceptual bridge from properties of individuals to properties of groups or families. In atoms and molecules correlation occurs because electrons interact with one another -- the electrons are interdependent. This electron correlation determines much of the structure and dynamics of many electron systems, i.e., how complex electronic systems are made from single electrons.
Interdependency of electrons in atoms, molecules and condensed matter is analogous to larger, more familiar systems. A symphony is composed of individual musical notes. Poems are constructed from words whose meanings are interconnected. A team is developed with individual people. But just as a fine meal in a good New Orleans restaurant is more than a mixed bag of groceries, new properties on the more complex scale may emerge from the interdependency of individual contributors so that the whole may be more than the sum of its parts. The challenge is to understand how this happens, to determine the patterns and rules.
Music, literature, social structure and good cooking are different from atomic physics. In the former we do not understand very well the nature of the interactions between the constituent contributors. But in atomic physics we do understand how the individual electrons interact with one another. The interaction is the simple Coulomb force. This interaction determines how the individual electrons influence one another in a complex many electron system. Thus, in atomic physics we have a way to try to understand in a clear way how interdependency operates -- i.e., how to make complicated molecules from simple atoms.
Chemists, biologists and physicists now know the atomic structure of many large interesting molecules including DNA. But we do not understand very well how these complex atomic systems operate. My research focuses on the dynamics of electron correlation in atomic and molecular interactions. Transitions of single independent electrons are relatively well understood. The challenge in my case is to understand the dynamics of correlated multi-electron systems in which more than single independent electron transitions occur. Some of my theory has been tested using antimatter, fast heavy ions and light from synchrotrons. But the challenge remains.
This is the theme of a book "Electron Correlation Dynamics in Atomic Collisions" ISBN (0 521 48020 5) now available from Cambridge University Press (England) or (New York) at a cost of about $80.
Like golf, this game is not as easy as one would sometimes like it to be. I enjoy playing golf with my friends. It is not that I play the game as well as I hope to. Rather, its a way to stay healthy and active and to spend some time with other people. From my point of view golf is challenging and its fun. In a way that is my attitude about my profession. The game of understanding how to make complicated systems form simple ones is also fascinating and enjoyable. And it is a satisfying activity to do with others.