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Superposed_Cat
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Hi all, I was wondering how wheeler came to the conclusion that an anti-particle is a particle going backwards through time?
dauto said:It is as real as anything else in physics. Physics is always done by matching a mathematical model to observations. If the model matches than it is a good model and that's all there is to it. In the Path integral interpretation of QM particles can move backwards in time.
phinds said:I'm pretty sure that's just a neat math solution that is not really believed to represent reality. In other words, it's like epicycles ... it will give you a good answer to calculations but it isn't real.
Superposed_Cat said:Hi all, I was wondering how wheeler came to the conclusion that an anti-particle is a particle going backwards through time?
I wouldn't put it that way. As somebody mentioned, you can say this about whole of QM, and it's true to an extent, but more importantly, all we have for descriptions at these levels are the models. And the particular model, RQFT, implies that time-reversed particle and anti-particle are equivalent.phinds said:I'm pretty sure that's just a neat math solution that is not really believed to represent reality. In other words, it's like epicycles ... it will give you a good answer to calculations but it isn't real.
The particle is just its 1D trajectory in 3+1 dimensional spacetime - there is no point in saying that it propagates forward or backward.BruceW said:That's an interesting point too. What is the definition of information and causality in this context? If we define causality to go in the direction of positive time (for timelike separated events), then when we do a CPT transform, this 'causality' direction would also swap, since the direction of positive time has also swapped. Sound about right?
The concept of an electron being a positron going backwards in time is known as the Feynman-Stueckelberg interpretation. It suggests that the electron and positron are actually the same particle moving forward and backward in time, respectively.
If an electron and positron are moving in opposite directions through time, their properties would also be reversed. This means that the positron would have a negative charge and the electron would have a positive charge.
One of the main pieces of evidence for this concept is the Dirac equation, which predicted the existence of antiparticles like the positron. Additionally, experiments such as the double-slit experiment and quantum tunneling have shown that particles can behave as if they are moving backwards in time.
The idea of particles moving backwards in time is still a topic of debate in the scientific community. Some theories, such as the Wheeler-Feynman absorber theory, suggest that time is symmetrical and that particles can move in both directions. Others, however, argue that the concept of particles going backwards in time goes against the arrow of time and causality.
While the Feynman-Stueckelberg interpretation is most commonly associated with electrons and positrons, some theories have suggested that other particles, such as photons, could also exhibit time-reversal symmetry. However, there is currently no experimental evidence to support this idea.