I recently co-authored a paper with Transactional Interpretation (TI) originator John G. Cramer, which derives the Born Rule (quantum probability rule) for radiative processes (emission and absorption) in a simple and transparent way, based on the Wheeler-Feynman-Davies’absorber’ theory of radiation. It also shows that absorption is indeed perfectly well-defined in TI (contrary to skeptical claims about that issue). The paper (recently accepted in International Journal of Quantum Foundations, ijqf.org) can be found here: https://arxiv.org/abs/1711.04501

11 thoughts on “Paper with John Cramer on Absorption in TI”

Dear Dr Kastner,
Perhaps you could help me with a question about the double slit experiment.We always read it is not possible to know through which slit the photon has passed when we observe the interference pattern on the screen.Since we Know the light speed,if we measure the amount of time which photon takes to reach the screen,isn’t it possible to infer the distance it has travelled and consequently the route it must have taken?
Tkanks,
Lineu

I think here you would run into the uncertainty relation. That is, you would need to measure the time of arrival (corresponding to a particular directional momentum) to a precision not possible without destroying the interference pattern.

But if we measure the time each photon takes to arrive at the screen imediately after it has got there,when all of the photons have finally completed their journey surely there will be an interference pattern,don’t you think?

In that case the measurement will not be precise enough to tell you which slit the photon went through.

But could we,in principle,devise some future technology which is precise enough to make such measurements?I mean,the problem seems to be a matter of technology,not a matter of principle.

No, it’s a matter of principle. In order to obtain precise enough time information, you have to intercept the photon as it was absorbed, which would destroy the interference. In other words, your time measurement would essentially become a directional momentum measurement, which would yield a ‘which-slit’ result (no interference). If you worked out the detailed calculation, the time of flight would come from specifying the spacetime trajectory (distance to the absorption site), which requires as input a directional momentum. The quantum level ‘knows’ that you’re using this input, so it knows that you’re actually measuring directional momentum. There is interference only if the time of flight is not determined beyond the uncertainty needed to allow for many different directional momenta.

Thanks a lot!
Perhaps you could also help me about entanglement.Could we try to explain the non local comunication entangled particles seem to imply if we imagine there is a wormhole between them?In that case,could we suppose that a de Broglie-Bohm real wave could travel between the particles?
I have recently read that maybe spacetime is made of entanglement.

It’s popular lately to account for entanglement in terms of wormholes, but in the RTI picture this is not necessary since entanglement among possibilities is a natural thing. The ‘wormhole’ account presupposes that everything physical happens in spacetime so some reason is needed for superluminal influences and wormholes seem to fill the bill. But if spacetime is not fundamental, and quantum interactions are prior to spacetime, we don’t need to invoke wormholes in order to account for apparent superluminal influences.

Is it possible to perform any experiments to confirm the PTI interpretation?How does PTI acount for the delayed choice Weeler ‘s experiment?If we leave the interferometer without the half-silvered mirror(close system)the actualization of the confirmation wave just ceases to exist?

RTI/PTI is empirically equivalent to standard QM. It is an interpretation of what the QM formalism represents. So there are no experiments that distinguish between RTI and standard QM. I discuss the transactional account of the delayed choice experiment in “Understanding Our Unseen Reality,” pp. 151-159.

Dear Dr Kastner,

Perhaps you could help me with a question about the double slit experiment.We always read it is not possible to know through which slit the photon has passed when we observe the interference pattern on the screen.Since we Know the light speed,if we measure the amount of time which photon takes to reach the screen,isn’t it possible to infer the distance it has travelled and consequently the route it must have taken?

Tkanks,

Lineu

I think here you would run into the uncertainty relation. That is, you would need to measure the time of arrival (corresponding to a particular directional momentum) to a precision not possible without destroying the interference pattern.

But if we measure the time each photon takes to arrive at the screen imediately after it has got there,when all of the photons have finally completed their journey surely there will be an interference pattern,don’t you think?

In that case the measurement will not be precise enough to tell you which slit the photon went through.

But could we,in principle,devise some future technology which is precise enough to make such measurements?I mean,the problem seems to be a matter of technology,not a matter of principle.

No, it’s a matter of principle. In order to obtain precise enough time information, you have to intercept the photon as it was absorbed, which would destroy the interference. In other words, your time measurement would essentially become a directional momentum measurement, which would yield a ‘which-slit’ result (no interference). If you worked out the detailed calculation, the time of flight would come from specifying the spacetime trajectory (distance to the absorption site), which requires as input a directional momentum. The quantum level ‘knows’ that you’re using this input, so it knows that you’re actually measuring directional momentum. There is interference only if the time of flight is not determined beyond the uncertainty needed to allow for many different directional momenta.

Thanks a lot!

Perhaps you could also help me about entanglement.Could we try to explain the non local comunication entangled particles seem to imply if we imagine there is a wormhole between them?In that case,could we suppose that a de Broglie-Bohm real wave could travel between the particles?

I have recently read that maybe spacetime is made of entanglement.

It’s popular lately to account for entanglement in terms of wormholes, but in the RTI picture this is not necessary since entanglement among possibilities is a natural thing. The ‘wormhole’ account presupposes that everything physical happens in spacetime so some reason is needed for superluminal influences and wormholes seem to fill the bill. But if spacetime is not fundamental, and quantum interactions are prior to spacetime, we don’t need to invoke wormholes in order to account for apparent superluminal influences.

Is it possible to perform any experiments to confirm the PTI interpretation?How does PTI acount for the delayed choice Weeler ‘s experiment?If we leave the interferometer without the half-silvered mirror(close system)the actualization of the confirmation wave just ceases to exist?

RTI/PTI is empirically equivalent to standard QM. It is an interpretation of what the QM formalism represents. So there are no experiments that distinguish between RTI and standard QM. I discuss the transactional account of the delayed choice experiment in “Understanding Our Unseen Reality,” pp. 151-159.

Sorry,I meant WITH the mirror!