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How the Quantum Eraser Rewrites the Past | Space Time | PBS Digital Studios
تم نشره في 2016/08/11
Try Audible: http://www.audible.com/spacetime Causality is meant to move in one direction: forward. But the Quantum Eraser experiment seems to reverse causality. How and why can this happen and what are the implications of this experiment on how we understand Quantum Mechanics and our greater universe? Get your own Space Time tshirt at http://bit.ly/1QlzoBi Tweet at us! @pbsspacetime Facebook: facebook.com/pbsspacetime Email us! pbsspacetime [at] gmail [dot] com Comment on Reddit: http://www.reddit.com/r/pbsspacetime Support us on Patreon! http://www.patreon.com/pbsspacetime Help translate our videos! /timedtext_cs_panel?tab=2&c=UC7_gcs09iThXybpVgjHZ_7g A Delayed Choice Quantum Eraser Kim, Yu, Kulik, Shih & Scully, 2000, Physical Review Letters v.84 p.1 http://arxiv.org/abs/quant-ph/9903047v1 Previous Episode on Can We Survive the Destruction of the Earth? ft. Neal Stephenson /watch/ER4KUdwlmjUlK Previous Episode on The Quantum Experiment that Broke Reality /watch/odjjsLSNM-pNj Gamma Ray Bursts by In a Nutshell /watch/YN7NV1CkyLRkN Episode written and hosted by Matt O’Dowd Made by Kornhaber Brown (www.kornhaberbrown.com) Comments answered by Matt MirceaKitsune /watch/k0wqdwrlysik2g5ric4015ixs1fmehjjfv21z=cl&ER4KUdwlmjUlq tsjoencinema /watch/p1yturyt5qajwm225fjtfgyzmz1rxa31z=cl&ER4KUdwlmjUlt Weapon Valhalla /watch/40jyklyojmyh3dth32enqfs4izrhw3h331z=cl&ER4KUdwlmjUly Narigone /watch/k0wqnhvpvuix2ra3cc40ai4pww3kfgwtfb21z=cl&ER4KUdwlmjUlq TimmacTR /watch/gaeiyhi2nnwx11jc40qhnty2bpyq5phn21z=cl&ER4KUdwlmjUli kaleb tandberg /watch/nvdzzzysfw4zyt320dk3u4vscy3pt221z=cl&ER4KUdwlmjUlz The deathless face of the unborn mind /watch/k0wrzwwvhcml0z3pjc40ug4fzkyzs53rtp21z=cl&ER4KUdwlmjUlr Error 404: Hodor Not Found /watch/40pbhjxlayr5szep32t34hhifuuxxfeg21z=cl&ER4KUdwlmjUlb
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So when you have entangled wave packets moving through the delayed choice experiment, as a single offer wave, the potential properties of "future" particles stemming from that offer wave are basically doled out to suitable absorbers in the system as you measure. Which explains all the seemingly retrocausal weirdness.
Which is also why when you measure the spin of an entangled particle the spin of the other instantly changes. The possibility of it being one or the other became finalized as soon as it was measured since measuring itself is what caused potential properties to manifest from possible ones into actual events at timelike intervals. ... 42
PS. ...maybe that's why each answer they provide us with discloses a 100 new questions... 33
To this I would add that, rather than “parallel” universes/realities, such a block universe might contain all possible trajectories and events in superposition — in other words, the firing/ slit passage/ measurement is all just one unitary event. Moreover, the detection display also exists in both wave and particle (and other?) format concurrently — the one emerging trajectory being the one that is observed/attended to (sort of in the way that a sculptor “attends” to particular molecules in a block of granite to reveal a statue).
In this scenario, there need be no wave function collapse (physical alteration). It would simply be the “collapse” or focus of attention by the observer on one possible trajectory.
An interesting/challenging implication of this would be that the appearance of cause-and-effect is also illusory — simply being events and phenomena that co-emerge when one particular world line is attended to.
The above might also illuminate the perennial question “do people have free will?” Along any particular world-line set, the opportunity-choice-outcome is one concurrent, co-emergent phenomenon. Yet the fact that we have a double-slit “paradox” suggests that choice is involved in regard to which world-line set the observer attends to. ... 10
Both results are absolutely the result of entanglement. It just depends on when we become entangled with it. If you measure the pattern after we entangle at the point of the double-slit you'll get a double slit pattern; if measuring the pattern is your point of entanglement you'll get the interference pattern.
The absolute hidden beauty of this experiment is that it proves that WE entangle with this experiment's system and will do so for every other experiment we devise. ... 7
1. Build the experiment from your brain
2. The experiment will now build your brain
3. Blow your brains out 42
I had surgery for that in 9th grade... 397
It is both snowing and not snowing until you look through the window. It's how I survive the winter. 65
Probably the most curious title yet! 56
Thanks for letting us know. 79
The splitters registering at A and B only destroy the interference pattern.
Those at C and D also destroy it. For each (C or D) you only get half a pattern.
When you combine these patterns for C and D you get the patterns for A and B.
Therefore the arguement of going back in time / re-writing the past is not made out.
This is shown by Sabine Hossenfelder in one of her YouTube videos.
Sean Carroll also makes reference to this point.
A similar arguement is also made in Jim Baggott’s Book ‘The Quantum Story’ chapter 33.
It may be worth doing an update for this episode (assuming not done already).
Love this channel so much ❤❤❤❤❤ ... 1
Thank you 3
negative particle: meet you on the other side
positive particle: only if no one sees us 66
I arbitrarily switch the paths to C and D on and off. Have I created a system that can send a message 1 minute into the past, by watching for the interference pattern and assigning a 1 or 0 based on whether I see one or not?
But then, if I receive a message like '10101' and one minute later I decide to invert my message and send '010101' instead, haven't I broken causality? ... 238
The universe is like a dream striving to make sense.
If you dream about some specific thing, it appears in your dream, but does the universe of your dream contain other things you haven't considered? In my view, if you look for them, either they exist or not, if you don't, it is undefined.
If you like the simulation hypothesis, you could argue that things not being defined when they don't need to save computational power. If that were the case, from my point of view, only what my senses perceive needs to be simulated at a given time. If i'm outside, a skybox follows me around. Haha. Actually that wouldn't be enough, skybox dynamics don't allow for a universe that makes sense. But, a simple universe like that could make sense to a child that doesn't know anything! Yes, but it wouldn't make sense as he/she/it grows older, and learns about the wind, and stuff. The universe needs to make sense back and forth in time, so maybe that is very memory inefficient lol, not like a computer game in which you compute events sequentially, you would have to know past present and future at the moment of experience.
yes we are all asleep in Zion...
ARGUE WITH ME, SCIENTISTS! I salute you. ... 28
Entangled particle A arrives at the screen, which detects if it's an interference pattern or a particle. It sends that information to the half-mirrors at the detectors. If it is an interference pattern, it makes the system swap them with 100% reflective mirrors.
Particle B's path is set up with mirrors so that it takes a detour and gives enough time for the above to happen. It then finally arrives at the full mirrors, so they always get reflected into the detectors that actually record the which-way information.
So now, you have an interference pattern and you also know the which-way information. ... 1
Universe: "Hold my beer..." 34
The electrons or photons (and they've replicated the experiment using molecules as large as Fullerenes, 60 carbon atoms arranged in a sphere called "Buckyballs") exist only as a probability distribution (the interference pattern) until the "player looks", and this specific "which way data" causes a random draw from the probability of the possibilities and the result is rendered on the screen - - it went through THIS slit and landed in THIS band, either the left one or the right. As long as the which way data is not available, you're still holding the dice in your hand, the screen shows the probability distribution (interference pattern) and there is no result rendered until it is called upon.
Check out Tom Campbell's new QM experiments to try to validate his VR theory. 🙏🏻
...
What patterns would we observe at the interference screen?
Could we predict the future 10 min / a year ahead, predict the fission event by observing a pattern on the nearby interference screen? ... 213
Setup:
1) Put detectors A and B on the moon so it takes approx 1.3 seconds for the photons to get to the detectors.
2) Have entangled super-positioned particles on both earth and moon (you'll see why later)
2b) Have detector power for A and B linked to the super positioned particle so that when it comes out of super position it will turn on the power for the detectors.
Experiment:
We then pass the photons though the double slit w/ crystal to split them into an entangled pair and observe the pattern on the screen.
The magic is that we then have 2 options at this point :
If we notice an interference pattern, we measure the super positioned entangled particle from setup step 2B which collapses super position both here and on the moon faster than the speed of light and the moon detectors A and B gain power and we say GOTCHA to the universe b/c we can figure out which slit the photon passed through AND have an interference pattern.
If we don't notice an interference pattern, then we can collapse a wave function without even measuring it, which is SUPER WEIRD and at minimum advances our understanding that even the possibility of being able to measure a photon collapses it's wave function even if we don't actually measure it..... and since we never measured the entangled particle from setup step 2B the detectors stay off and never measure the entangled pair.
ELON MUSK --- GET ON THIS! LOL ...
I don't have a background in the math necessary to do this or to understand if this is even a dumb question or not. ... 50
Set up a quantum eraser experiment. The detector screen is a space ship/colony hours or years away. The light going to the eraser is bounced around for a bit longer than it's counterpart before its send to its detector/eraser component.
You send out enough fotons in one burst to discern an interference or band pattern. These are counted as bits: Interference patterns are the 0, band patterns are the 1.
The system is continuously sending bursts at speeds similar to modern computers.
Now give control over the mirrors to a computer. For each 0 the computer lets the fotons bounce into the erasor part creating an interference pattern. For each 1 the computer bounces it into the detector.
Add a specific pattern each time no input is given by the computer so it can be recognized.
The decision which one is an interference pattern and which one is a band pattern is made at almost the same time as the interference pattern reaches the ship/colony.
On the space ship/colony they detect a series of interference patterns band patterns which are translated into bits and into messages. While it took the fotons hours or years to reach it, the information created within is made almost at the same time.
Now someone explain to me how this would still not work, because there is always a reason but people rarely give an actual explanation when I ask why.
I only recently started watching your series and it's awesome!
Got a question though... According to relativity, and applying the time dilation / length contraction formulae from the perspective of the photon, the universe contracts to an infinitesimal point and time does not change. Therefore, according to the photon (and yes, this point of view could be considered pointless - double pun intended), there is no "going back in time" and therefore no "changing the past". As I might have hinted already: is there any point in considering this? Does this "explain" (as far as explaining is actually possible in the quantum realm) what happens?
Cheerio! ...
- Albert Einstein 281
These lateral temporal paths could create a spread of possible locations for a particle in our particular experience of the flow of time. This could (if I understand properly) also explain why the act of any distinctly “forward” or “backward” moving particle measuring a particle of unknown temporal trajectory causing the wave function to collapse. Much like particle “spin” aligns itself with the measuring device we use, since we would be measuring temporal trajectory with a collection of forward moving particles, the temporal trajectory would align forward in time in a sense causing the wave function to collapse at whatever point the particle was measured. Further, this could help explain why greater mass decreases uncertainty, as it could explain mass as a forward/backward momentum through time. The more massive the object, the more temporal momentum, and that could create inertia that helps prevent lateral movement through time.
I actually have many other things I believe could be explained by this (dark matter could be matter that moves laterally through time by our reference frame as an example, but would be impossible for us to directly see since it would be measured with a forward/backward reference), but I was wondering if this is something that has been explored already and disproven. Or, perhaps I am positing this with such a poor understanding of the concepts that it isn’t particularly worthwhile to ask? ... 4