Register | Sign In


Understanding through Discussion


EvC Forum active members: 57 (9173 total)
0 online now:
Newest Member: Neptune7
Post Volume: Total: 917,585 Year: 4,842/9,624 Month: 190/427 Week: 0/103 Day: 0/8 Hour: 0/0


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   Card testing experiment challenge
Syamsu 
Suspended Member (Idle past 5670 days)
Posts: 1914
From: amsterdam
Joined: 05-19-2002


Message 1 of 6 (490602)
12-06-2008 7:04 AM


I was thinking to do a revised version of the bomb testing experiment.
Elitzur—Vaidman bomb tester - Wikipedia
So now what I will do is to set up the circuit in my brain, and substitute testing the bomb with drawing a card. To start I get 2 cards one black, one red, shuffle them so I don't know which one is on top.
First I make a prediction which card is on top, red or black. Then in my head at point A I decide to draw the card or not. Extended form that choice I try to choose between C and D, having previously made a determination to stop if the card drawn is the same as the card predicted.
There are many difficulties with this:
- choosing to draw the card or not, while one is inclined to draw the card
- making the upper and lower path equivalent so that trying to choose between C and D is at a point of interference
- automating the determination to stop if the card is the same and letting pass through if the card is unequal
This circuit needs to be extended to get prox 100 percent certainty, in the way referenced in the paper.
So let's all try this experiment and see who get's the best result, and that will probably be the person who has the tidiest mind!

Replies to this message:
 Message 2 by Admin, posted 12-06-2008 8:24 AM Syamsu has not replied
 Message 3 by Admin, posted 12-07-2008 5:47 AM Syamsu has replied

Admin
Director
Posts: 13081
From: EvC Forum
Joined: 06-14-2002
Member Rating: 2.4


Message 2 of 6 (490606)
12-06-2008 8:24 AM
Reply to: Message 1 by Syamsu
12-06-2008 7:04 AM


Hi Syamsu,
I may need help from people knowledgeable about quantum theory before making a decision on this one. I can't tell if the Wikipedia article on the Elitzur-Vaidman bomb-tester makes legitimate use of quantum theory, is highly speculative, or is completely bogus.
So let me describe what appears to me to be a contradiction and see if we can resolve it to give me more confidence in the article. First, here's their diagram:
The B in the red explosion is a bomb that is either a real bomb or a dud, and the text tells us that what is represented by the B is a mirror attached to a plunger which is attached to the bomb's detonator:
Now consider a slight variation: a mirror attached to a plunger, which is attached to the detonator.
And the text says that when a photon strikes the mirror it pushes the plunger and detonates the bomb:
A photon that impinges on the mirror pushes the plunger and this detonates the bomb.
The text goes on to say that a dud is one whose plunger is stuck, so that when a photon hits the bomb's mirror, the plunger doesn't move and the bomb doesn't explode. Photons are reflected from the mirrors of dud bombs:
The duds are those bombs whose "plunger" is stuck, so that even if a photon hits the mirror, the plunger does not get pushed, and no detonation occurs. This property is important, because it means a dud effectively just reflects the photon.
Now here's where things go awry. Further on in the text under the heading "If the bomb is a dud" it says that a dud bomb will not absorb the photon and that therefore the bottom horizontal path is a possible route to the detectors at C and D:
The bomb will not absorb a photon, and so the lower route is a possible path to the point of interference.
But the bomb's mirror is supposed to reflect the photon, presumably back to A, not transmit it.
This tells me that the diagram is misdrawn. The bomb B is not actually an element midway between the lower two mirrors. Rather, the lower right hand mirror is the bomb's mirror, and the B should be moved over to the right of it outside the path between the lower two mirrors. In other words, the diagram should look like this:
And what the text is telling us is that a good bomb's mirror absorbs the photon and explodes. In other words, the good bomb acts as an observer. A dud bomb reflects the photon up to the detectors at C and D.
Another less convoluted formulation is that this is a way of telling whether the mirror in the lower right hand corner is actually a mirror or a detector. The device can purportedly tell you when it is a detector without ever setting off the detector.
Cavediver, Son Goku or anyone else knowledgeable about quantum theory, if you care to comment about this analysis please post to Topic Proposal Issues.
Edited by Admin, : Fix link.

--Percy
EvC Forum Director

This message is a reply to:
 Message 1 by Syamsu, posted 12-06-2008 7:04 AM Syamsu has not replied

Admin
Director
Posts: 13081
From: EvC Forum
Joined: 06-14-2002
Member Rating: 2.4


Message 3 of 6 (490677)
12-07-2008 5:47 AM
Reply to: Message 1 by Syamsu
12-06-2008 7:04 AM


Syamsu writes:
First I make a prediction which card is on top, red or black. Then in my head at point A I decide to draw the card or not. Extended form that choice I try to choose between C and D, having previously made a determination to stop if the card drawn is the same as the card predicted.
Point A is not a decision point. In the bomb example the photon is always fired from A - there is no decision about whether to fire it or not. By including a decision to draw the card or not you've broken the analogy with the bomb example.

--Percy
EvC Forum Director

This message is a reply to:
 Message 1 by Syamsu, posted 12-06-2008 7:04 AM Syamsu has replied

Replies to this message:
 Message 4 by Syamsu, posted 12-07-2008 6:17 AM Admin has not replied

Syamsu 
Suspended Member (Idle past 5670 days)
Posts: 1914
From: amsterdam
Joined: 05-19-2002


Message 4 of 6 (490678)
12-07-2008 6:17 AM
Reply to: Message 3 by Admin
12-07-2008 5:47 AM


Maybe there is some error in it, that's up for discussion, investigation. I can't even say for sure if you're right or wrong about it. Remember the other reference is seaching a database with a quantum computer, brains are quantumcomputers, and a deck of cards is a database of sorts, and it is about choosing, so the ingredients are correct.

This message is a reply to:
 Message 3 by Admin, posted 12-07-2008 5:47 AM Admin has not replied

Syamsu 
Suspended Member (Idle past 5670 days)
Posts: 1914
From: amsterdam
Joined: 05-19-2002


Message 5 of 6 (490705)
12-07-2008 11:12 AM


I retract the topic. This doubting about common knowledge of freedom, choosing, you all engage in, that the majority of scientists engage in, as you can read on the wikipedia philosophy page about free will for instance, is just plain evil. Unconsciounable intellectual violence sure to hurt many common people dealing with identity issues. I am throwing pearls to swine.

Replies to this message:
 Message 6 by Admin, posted 12-07-2008 1:30 PM Syamsu has not replied

Admin
Director
Posts: 13081
From: EvC Forum
Joined: 06-14-2002
Member Rating: 2.4


Message 6 of 6 (490714)
12-07-2008 1:30 PM
Reply to: Message 5 by Syamsu
12-07-2008 11:12 AM


Hi Syamsu,
I gave the Wikipedia article you cited a very careful read, I gave you comments about what I thought was wrong with it, and later I described how the proposal from your opening post was inconsistent with the thought experiment described in the article. I was trying to give your proposal the best chance of success, but I can't do that if you won't work with me.
I think it's time for you to move on. Thank you for your contributions over the years, and good luck to you in the future.

--Percy
EvC Forum Director

This message is a reply to:
 Message 5 by Syamsu, posted 12-07-2008 11:12 AM Syamsu has not replied

Newer Topic | Older Topic
Jump to:


Copyright 2001-2023 by EvC Forum, All Rights Reserved

™ Version 4.2
Innovative software from Qwixotic © 2024