The discussion centers on the relationship between spacetime and the quantum vacuum, particularly in the context of special relativistic quantum field theory and string theory. It establishes that, at low energies, the quantum vacuum exists within spacetime, while at high energies, the understanding of quantum gravity becomes uncertain. Theories suggest that spacetime may be an excitation of the quantum vacuum, indicating a complex interplay between these two concepts. This leads to the conclusion that low-energy approximations may not fully capture the true nature of spacetime and the quantum vacuum.
PREREQUISITESThe discussion is beneficial for theoretical physicists, cosmologists, and advanced students interested in the foundations of quantum gravity and the nature of spacetime.
atyy said:In special relativistic quantum field theory, the quantum vacuum is in spacetime. This sort of theory describes our universe at low energies.
At very high energies, our current understanding of quantum gravity breaks down, and theorists are working on a good "UV completion" of quantum gravity. In string theory, which is a candidate UV complete theory of quantum gravity, one view of spacetime is as an excitation of the some quantum vacuum. http://homepage.mac.com/photomorphose/documents/qpdf.pdf