quantum field theory in curved space time

Quantum field theory in curved space time how to#
Quantum field theory in curved space time series#

Quantum field theory in curved space time series#

We are going to study linear quantum field theories which, although simpler than fully interacting ones, have a series of subtle and physically remarkable properties.

Quantum field theory in curved space time how to#

$^*$ I don't know of any well-developed proposals for how to get by without a fixed asymptotic spacetime structure, and I have seen general arguments that such a structure is necessary. Much of the theoretical basis for this understanding comes from the study of quantum field theory in curved space-times, which is the subject of this chapter. CFT is relatively well-understood mathematically, but exactly how spacetime and gravity manage to emerge is still an active research area, as is the question of how to extend the idea to spacetimes with more realistic asymptotic conditions (namely de Sitter). This can be regarded as defining a theory of quantum gravity (string theory) in asymptotically-AdS spacetime in terms of a conformal quantum field theory (CFT) associated with the asymptotic structure. Currently, the best-understood example of this kind of theory comes from the AdS/CFT correspondence. The correct theory of quantum gravity remains to be determined. Quantum gravity: This refers to a fully quantum theory with no fixed background metric (except for its asymptotic structure) $^*$, but which nevertheless exhibits gravity in a way that is well-approximated by general relativity under appropriate conditions. The inconsistency is explained in this blog post: Luboš Motl (2012), 'Why 'semiclassical gravity' isn't self-consistent,' It has been used, for example, to try to account for the fact that a black hole should lose mass as it radiates. This formulation is accomplished via the algebraic approach, which, in essence, simultaneously admits all states in all possible (unitarily. We review the mathematically rigorous formulation of the quantum theory of a linear field propagating in a globally hyperbolic spacetime. Semiclassical gravity: This name often refers to an approximation that attempts to account for how the spacetime metric would react to the quantum fields, but still using a classical description for the metric (so that the metric commutes with all operators on the Hilbert space). Quantum Field Theory in Curved Spacetime.

Tests of quantum effects in free-fall don't count, because they're not sensitive to the curvature. I'm not aware of any direct tests of the effect of spacetime curvature on quantum fields, although there are plenty of tests of the effect of spacetime curvature on classical approximations of quantum fields. A special case of QFT in curved spacetime is QFT in flat spacetime, which of course is very well-tested. Oscilloscope Quantum Mechanics Relativity. Hawking radiation can be derived using this approximation, but the black hole never evaporates in this approximation, because the spacetime metric does not react to what the quantum fields are doing. If you increase of sin() each 16 process is repeated, it looks like a different wave swells each time. (This prevents faster-than-light communication.) This approximation is self-consistent. The fixed metric field defines what 'spacelike' means, which is important because observables built from the quantum fields are required to commute with each other at spacelike separation. It doesn't react to the state of the quantum fields, which are described by operators on a Hilbert space. D, 13, 198 (1976).QFT in curved spacetime: The spacetime metric is fixed. S., and DeWitt, C.), (Gordon and Breach, 1973).ĭavies, P. W., Cosmological Event Horizons, Thermo-dynamics and Particle Creation, Univ. W.), (Oxford University Press, Oxford, 1975).Īshtekar, A., and Magnon, A., Proc. Quantum Gravity-An Oxford Symposium (edit.