On Fri, Aug 9, 2019 at 7:49 PM Bruno Marchal <[email protected]> wrote:
> On 9 Aug 2019, at 04:07, Bruce Kellett <[email protected]> wrote: > > From: Bruno Marchal <[email protected]> > > On 8 Aug 2019, at 13:59, Bruce Kellett <[email protected]> wrote: > > On Thu, Aug 8, 2019 at 8:51 PM Bruno Marchal <[email protected]> wrote: > If the superposition are not relevant, then I don’t have any minimal > physical realist account of the two slit experience, or even the stability > of the atoms. > > Don't be obtuse, Bruno. Of course there is a superposition of the paths in > the two slit experiment. But these are not orthogonal basis vectors. That > is why there is interference. > > > But each path are orthogonal. See the video of Susskind, where he use 1 > and 0 to describe the boxes where we can find by which hole the particles > has gone through. Then, without looking at which hole the particle has gone > through, we can get the interference of the wave which is obliged to be > taken as spread on both holes, and that represent the superposition of the > two orthogonal state described here as 0 and 1. > > I seldom watch long videos of lectures. But if Susskind is saying that the > paths taken by the particle through the two slits are orthogonal then he is > flatly wrong. Writing the paths as 1 and 0 does not make them orthogonal. > And if they were orthogonal they could not interact, and you would not get > interference. Two states |0> and |1> are orthogonal if their overlap > vanishes: <0|1> = 0. Interference comes from the overlap, so if this > vanishes, there is no interference. > > Either Susskind is terminally confused, or you have misrepresented him. > > Or maybe you are wrong. Slit one is orthogonal to slit two, as much as > spin in different direction. > When you observe which slit the particle went through, then yes -- the slits are then orthogonal eigenstates of the position operator. The interference comes from the fact that we get a superposition of going > through slit one + going through slit two when we send a planar > monochromatic wave on the wall with the two slits, and don’t measure which > slit the particle go through. > Yes, then the states that we are measuring are not orthogonal. You do not get interference between orthogonal states. > That is how Susskind explains the two slit experiment in term of > entanglement. You don’t need to look at the whole video, I gave the > position of this sub-talk in the video. > > Any crisp measurement, like “which slit” gives rise to orthogonal state, > which can interfere when superposed. > Which is essentially what I said -- orthogonal states do not interfere. Bruce -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLT-P23Vk522Y-H-TBdCGtjdyage%3D%3DZz1grQwAgudjqJkw%40mail.gmail.com.
