the Rydberg series
Rydberg atoms are extremely cool, and are very much worth talking about for a bit. I haven't uncovered a great source written for a layperson like me that wants some amount of detail but can't follow exclusively technical documents (as of March 2010, even the Wikipedia article assumes more background knowledge than I can bring to bear), but a painfully brief mention in the article "Heisenberg's Uncertainty Principle and the Many-Worlds Interpretation of Quantum Mechanics" from Douglas Hofstadter's Metamagical Themas is very tantalizing. Although it is surely a grossly basic and at least partly misleading characterization, here goes:
When I was in elementary school, we were still taught the Bohr model of an atom, wherein electrons orbit a nucleus of clumped protons and neutrons almost like planets around the sun. Of course, by this time (the early 1980s) it was already well-known that this classical model of the atom was completely wrong. Electrons exist in a quantum mechanical state almost like probabilistic clouds around the nucleus. We can define the position of an electron with a particular energy only by recourse to uncertain probabilities; we know the most likely possible positions and these form various enticing shapes surrounding the nucleus at various distances.
When an atom is put into a so-called Rydberg state, one or more of it's outer electrons (also called valence electrons) is/are excited massively such that they are shot out into a much higher-energy—and thus further away— orbital. When this happens, the super-energized valence electron begins to behave more like the old planetary model predicts. It's the revenge of classical mechanics! Atoms in such states apparently have all sorts of cool properties which, so far, I don't really understand at all. But it's the collision of classical and quantum mechaics that turns me on.
A quick example will serve to explain the form of these piece's titles. So far, I think I've gleaned that Calcium atoms are particularly popular experimental subjects for Rydberg manipulation. Normally, we would notate the atomic orbital state of a calcium atom as [Ar]4s2, which means that the first eighteen electrons are distributed as in argon (whence the "[Ar]" shortcut), and the final two electrons fill out the fourth s-orbital (whence "4s2"). The details are unimportant for this discussion, but essentially, one of these outer electrons is energized into a massive orbital, such as the seventeenth d-orbital (4s117d1) or the eighteenth p-orbital (4s118p1), etc. To some extent, this extreme valence electron then proceeds to orbit the rest of the atom. In essence, the rest of the atom acts like a "nucleus" with a single electron around it, like some kind of fucked up Hydrogen atom.
And so anyway, the inspiration for these pieces is trying to find different musical textures and structures that somehow emulate both "classical" ideas—point-like sounds, regular patterns, "logical" tone rows, etc.—and "quantum" ideas—random passages, unpredictable rhythms, cluster harmonies, etc. I'm particularly interested in finding sounds and ideas which somehow blur the line between, such as simple triadic harmonies emerging from and receding back into cloudy clusters or single ideas that gradually proliferate and become a mass of sound.
PortRait of the ArTist,**NYC2001
Note: The "order" of these pieces is less obvious than others, which tend to be numnbered or lettered in a more or less clear way. This is mostly deliberate, although so far I have been putting the outermost valence electron (see above) in a higher and higher energy level as these pieces accrue. Eventually, I think I'm going to get bored with calcium atoms (again, see above) and might have different atomic orbital notations. Order will then be indicated first by atomic weight and then by higher-energy valence orbital within the same atomic weights (seriously, this will all make more sense if you read the program above).