The discussion centers on whether spatial and temporal orientation in relativistic field theory is a convention. Participants clarify that while Minkowski spacetime is orientable, the choice of orientation is indeed a convention, as it does not dictate physical reality. However, the orientation of physical measuring devices and certain tensorial fields is not a convention, as these have specific transformation properties that are dictated by the underlying physics. The conversation highlights the distinction between coordinate choices and the inherent properties of physical objects.
PREREQUISITESPhysicists, particularly those specializing in theoretical physics, relativistic field theory, and particle physics, will benefit from this discussion. It is also valuable for students and researchers interested in the foundational aspects of spacetime and orientation in physics.
My point was that you need a reference, which you can choose by convention. An objective one, transportable to any place and valid at any time, according to the HEP Standard Model, is the left-handedness (right-handedness) of neutrinos (anti-neutrinos). Then you can define of any (chiral) object which orientation it has relative to the so defined properties "left" and "right". That's indeed independent of the choice of coordinates.PeterDonis said:Yes, but the fact that one cannot be continuously transformed into the other is not. So there are two orientations, which we can label however we want, and given any physical object, we can check which orientation it can be continuously transformed into and which one it can't. The result of this check is independent of any coordinate choice or any choice of labeling of orientations; that is the sense in which a physical object has an orientation that is not a convention. (The only complication here is that some objects, for example a perfect sphere, will not have an orientation in this sense.)
vanhees71 said:you need a reference, which you can choose by convention
vanhees71 said:An objective one, transportable to any place and valid at any time, according to the HEP Standard Model, is the left-handedness (right-handedness) of neutrinos (anti-neutrinos)