Timeline for What is spacetime?
Current License: CC BY-SA 4.0
5 events
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| Oct 29, 2019 at 13:05 | comment | added | Andrew Steane | @Ivella The question asked what is spacetime. The physical picture of quantum fields everywhere is likely to remain broadly correct as a more complete understanding is developed. Also, the difficulty with QFT and GR is not quite corrrectly described as straight incompatibility. QFT is compatible with special relativity, and in a similar way it is compatible with general relativity except in extremes of curvature or when there is entanglement involving significantly different metrics. | |
| Oct 29, 2019 at 11:58 | comment | added | lvella | I don't like this answer because spacetime and quantum fields arises from completely different and incompatible theories. We have no idea how the two of them interact precisely, and this answer just assume space time is made up by quantum fields because that is an intuitive feeling. | |
| Oct 29, 2019 at 9:04 | comment | added | Andrew Steane | @undefined At the moment we calculate this by treating the quantum fields as located in a classical spacetime described by GR. In the classical limit one ends up with ordinary clocks and rods responding to the gravitational stress tensor. The fact that one cannot detect gravity at a point follows from the Equivalence Principle. This can in turn be seen as owing to the fact that the metric is Minkowskian in the vicinity of any event. | |
| Oct 29, 2019 at 8:05 | comment | added | undefined | How does one calculate the disturbance of the quantum fields caused by gravitational waves and how can one mathematically proof that it is not possible to detect this disturbance at a single point? | |
| Oct 28, 2019 at 22:03 | history | answered | Andrew Steane | CC BY-SA 4.0 |