This 2002 novel chronicles attempts to crunch spacetime using a supercomputer named a Sonomak, in a project at Georgia Tech in Atlanta.
When something goes a little wrong -- Dr Frankenstein, I presume? -- and a miniaturized creation -- a Picoverse -- is created, then things get interesting.
In Picoverse (the story) we have the creation and visiting of different alternate worlds, created by the misfiring of plasma injectors into magnetic fields (or something). Each universe is created as an exact duplicate of ours, up until the moment of divergence.
These worlds' scale (physical and temporal) are smaller in relation to ours, so, as in Theodore Sturgeon's classic tale "Microcosmic God," whole generations might pass in a picoverse in the course of a conversation on our plane.
But it's the tales of the characters, and their passages into various worlds, and interactions with their alternate selves and with other people, that make Picoverse so much fun and moving and insightful.
Metzger shows insights into many facets of the human character, including some we don't like to acknowledge -- pettiness, jealousy, selfishness, outright self-righteous justification. But the people in Picoverse also try to help themselves and others. They have loves and selfless motives and self-sacrifice.
Sometimes these polarities of human behavior are even shown in the same character, at different times.
Picoverse is a fun book, not an easy read if you're not up on physics (as I am not), but loaded with ideas and observations and people who make you want to know what will happen next to them.