Direct observation

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PJay_A

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<p>Q:</p><p>If a photon passed a beam splitter that tunneled it directly to a human observer's left and right eyes, would it be observed by either eye or by both eyes?</p>
 
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Mee_n_Mac

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Q:If a photon passed a beam splitter that tunneled it directly to a human observer's left and right eyes, would it be observed by either eye or by both eyes? <br />Posted by <strong>PJay_A</strong></DIV><br /><br />Interesting question !&nbsp; You can split an individual photon but the experiments I know of then have it recombining with itself before the detector.&nbsp; In your case we have 2 paths, 2 detectors. I say it'll be seen 50% of the time in one eye or the other but not in both simultaneously.&nbsp; Now hopefully a qualified person will answer.</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p>-----------------------------------------------------</p><p><font color="#ff0000">Ask not what your Forum Software can do do on you,</font></p><p><font color="#ff0000">Ask it to, please for the love of all that's Holy, <strong>STOP</strong> !</font></p> </div>
 
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DrRocket

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Interesting question !&nbsp; You can split an individual photon but the experiments I know of then have it recombining with itself before the detector.&nbsp; In your case we have 2 paths, 2 detectors. I say it'll be seen 50% of the time in one eye or the other but not in both simultaneously.&nbsp; Now hopefully a qualified person will answer.&nbsp; <br />Posted by mee_n_mac</DIV></p><p>You are correct.&nbsp; A photon is a single particle.&nbsp; If&nbsp;you make some observation that detects it, like detecting it with your retina, then it will have a definite position -- in one eye or the other but not both.&nbsp; <br /></p> <div class="Discussion_UserSignature"> </div>
 
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MeteorWayne

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>You are correct.&nbsp; A photon is a single particle.&nbsp; If&nbsp;you make some observation that detects it, like detecting it with your retina, then it will have a definite position -- in one eye or the other but not both.&nbsp; <br />Posted by DrRocket</DIV><br /><br />Of course, this is a theoretical experiment, since the human eye-brain cannot perceive one photon.</p><p>By the time the visual system can respond, there are many photons involved.</p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
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DrRocket

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Of course, this is a theoretical experiment, since the human eye-brain cannot perceive one photon.By the time the visual system can respond, there are many photons involved. <br />Posted by MeteorWayne</DIV></p><p>I am not certain about that.&nbsp; The rods are pretty sensitive.&nbsp; I an not sure what the sensitivity threshold is.&nbsp; I do know that in observing stars sometimes the star excites a single rod. </p><p>But there are detectors that can register a single photon, and they are not found just in laboratories.&nbsp; I know of units fielded for military purposes that can detect and sound and alarm on the basis of one photon.&nbsp; <br /></p> <div class="Discussion_UserSignature"> </div>
 
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nimbus

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I am not certain about that.&nbsp; The rods are pretty sensitive.&nbsp; I an not sure what the sensitivity threshold is.&nbsp; I do know that in observing stars sometimes the star excites a single rod. But there are detectors that can register a single photon, and they are not found just in laboratories.&nbsp; I know of units fielded for military purposes that can detect and sound and alarm on the basis of one photon.&nbsp; <br /> Posted by DrRocket</DIV><br />One of my college biology textbooks mentionned that certain frogs (or toads) could see individual photons. I reckon they'd have picked a less outlandish example like the human eye if it were capable of it too.</p><p>http://math.ucr.edu/home/baez/physics/Quantum/see_a_photon.html</p> <div class="Discussion_UserSignature"> </div>
 
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MeteorWayne

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>One of my college biology textbooks mentionned that certain frogs (or toads) could see individual photons. I reckon they'd have picked a less outlandish example like the human eye if it were capable of it too.http://math.ucr.edu/home/baez/physics/Quantum/see_a_photon.html <br />Posted by nimbus</DIV><br /><br />But from your link...</p><p>&nbsp;</p><p>"The human eye is very sensitive but can we see a single photon?&nbsp; The answer is that the sensors in the retina <em>can</em> respond to a single photon.&nbsp; However, neural filters only allow a signal to pass to the brain to trigger a conscious response when at least about five to nine arrive within less than 100 ms.&nbsp; If we could consciously see single photons we would experience too much visual "noise" in very low light, so this filter is a necessary adaptation, not a weakness."</p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
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DrRocket

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>But from your link...&nbsp;"The human eye is very sensitive but can we see a single photon?&nbsp; The answer is that the sensors in the retina can respond to a single photon.&nbsp; However, neural filters only allow a signal to pass to the brain to trigger a conscious response when at least about five to nine arrive within less than 100 ms.&nbsp; If we could consciously see single photons we would experience too much visual "noise" in very low light, so this filter is a necessary adaptation, not a weakness." <br />Posted by MeteorWayne</DIV></p><p>So frogs have less of a brain block than humans, huh?&nbsp; I can think of a few people for whom that certainly appears to be true.&nbsp; Not sure it applies to everyone though.<br /></p> <div class="Discussion_UserSignature"> </div>
 
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