Department of Science, Math, & Technology

E = mc²
People can see single photons (sometimes)
Posted: Posted October 3rd, 2017 by Xhin
 “The most amazing thing is that it’s not like seeing light. It’s almost a feeling, at the threshold of imagination,” https://www.nature.com/news/people-can-sense-single-photons-1.20282 It's been known for a long time that eye cells called "rods" can detect single photons, meaning that humans can sense fundamental particles on some level, but it wasn't known until very recently (2016) whether people could *sense* single photons. Subjects were left in a dark room for 40 minutes and then got to press a button. There would be two clicks, and they'd have to determine which of them had light with it. They then did this for 42,600 trials for each of three subjects. While it wasn't 100%, the detection rate was more than random, and the confidence rate was significantly higher when right guesses were made. So that's pretty cool.
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There are 3 Replies

Pretty neat. Seems like the article says 2,400 trials, not 42,600, however.

I want to sit in a dark room and have scientists shoot things at my eyes.

How do they ensure that just a single photon is released?

Posted October 7th, 2017 by EN

Amazing indeed! It reminds me of the double slit experiment where it is said that even if you shine a single photon or a single electron, it would still produced the quantum interference pattern on a screen that a beam of them would produce. (So the pattern stays the same regardless of intensity of the beam, which is given by the number of particles in it.)

I'm not sure how to answer EN's good question, but perhaps one way to do it would, for example, be by having an excited hydrogen atom (say at the n=2 state) and then have its electron emit one photon of energy when it goes to the ground state (n=1). Another way may be in terms of the energy felt by the stimulus verses how that energy compares with that of a single photon of light using Planck's equation $$E = h\nu$$.

Edited October 8th, 2017 by The Fly

This sounds cool until you see the sample size.

Posted October 10th, 2017 by Kohlrak
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