The quantum Universe

摘要

In the centenary year of Einstein's seminal contributions to human culture, Science and Ultimate Reality celebrates the 90th birthday of John Wheeler, who took two of Einstein's ideas and created new branches of science. The physics of the twentieth century was built on the twin pillars of Einstein's general theory of relativity and quantum mechanics. The former describes the macroscopic Universe of space-time and gravitation, and the latter is a theory of matter and radiation at subatomic dimensions. These two different theories seem to be incompatible, but Wheeler insisted that, at some level, quantum effects must have a meaningful impact on gravitational physics. And because Einstein's theory intimately links gravitational physics with geometry, the net result must be some sort of quantum space-time dynamics. It was using this reasoning that Wheeler predicted in 1957 the existence of space-time foam, one of many of his ideas that survive to this day.