Quantum theory's last challenge

摘要

Quantum theory is 100 years old and still going strong. Combining general relativity with quantum mechanics is the last hurdle to be overcome in the 'quantum revolution'. This year we celebrate 100 years of quantum theory, and in particular the anniversary of an announcement made by Max Planck at a meeting of the German Physical Society on 14 December 1900. Planck was interested in the nature of radiation emitted by hot objects, and in 1900 he devised a theory that described all of the experimental evidence, but that required a radical new concept: energy is not emitted or absorbed continuously, but in discrete amounts, called quanta. At the time, Planck was not aware of the profound consequences of his work, but gradually physicists realized that they needed quantum concepts to understand the structure of all matter and radiation.