Talk:Shot noise

message: i thought shot noise was to do with electrons passing over a junction between two different conducting materials? ill go else where and check... mark_metcalfe@hotmail.com —Preceding unsigned comment added by 158.125.1.23 (talk • contribs) 
: I think that's called a flicker noise... kuevis@hotmail.com —Preceding unsigned comment added by 150.150.77.68 (talk • contribs) 
Hi,
You are absolutely right, and this page needs some editing. I think I or someone with more detailed knowledge should do this.
Briefly speaking, the granular nature of charge is not responsible for shot noise by itself. Shot noise occurs when charge carriers must cross a junction.
So for instance, a copper wite carrying current will exhibit only thermal noise but not shot noise, while a semiconductor junction will exhibit both.
Flicker noise is an altogether different phenomenon, and while there are several theories and models regarding flicker noise, there is no universally accepted physical model to explain it yet (perhaps a Nobel Prize waiting for someone), despite and perhaps owing to its universal nature. It is seen in phenomena from microscopic scale to the astronomical scale.
Vivek
vivkr .at. yahoo . com —Preceding unsigned comment added by 62.218.180.1 (talk • contribs) 
: I believe you are rong. Shot noise occours in copper wires. Some discussion could take place due to the less deffined position of electrons in copper, but this only reduces the bandwith of the noise and not the its power.
: I believe flicker noise is usually due to electron traps in the potential barrier beetwen conductors and isolators.
: --Paclopes 19:37, 18 January 2007 (UTC)
thread_title:  nature of shot noise 

message: Why there are no formulas for shot noise?! The page is only talk.... Somethink like 
:
I_{sh} = \sqrt{2 q I_{dc} \Delta f}
:Please define delta f File Not Found 20:09, 22 September 2007 (UTC)
thread_title:  formulas 

message: Agree PAR 03:43, 5 November 2006 (UTC)
thread_title:  Merge [[Photon noise]] into this article 

message: Can someone fact check these edits?  I don't understand the changes that were made or why some of the content was deleted. — Omegatron 00:59, 15 November 2006 (UTC)
replies: text: Hmmmm! I suggest we revert pending me finding my book on Noise ! 8-)--Light current 01:48, 15 November 2006 (UTC)
thread_title:  Deletion of content 

message: The article launches into the topic in a fairly technical manner and never explains why it's called 'shot' noise. The way I was introduced to the phenomenon was to imagine the difference between a cup of molten lead being poured onto a surface vs a cup of lead shot. This can also be extended to cover the phenomenon's relevance to extremely low level signals with a bit of imagination. Does someone more eloquent than me want to tackle this before I make a hash of it? :) MagnusL (talk) 11:21, 21 November 2007 (UTC)
thread_title:  simple analogy for non specialists 

message: The wrong SNR is given. You don't have to deal with the signal amplitude and the standard deviation, but with powers/energys, i.e. with the squared amplitude and the variance. Hence, the signal-to-noise ratio of shot noise is N.  —Preceding unsigned comment added by 65.202.28.10 (talk) 22:42, 13 December 2007 (UTC)
thread_title:  Wrong SNR 

message: I thought it was only when crossing junctions of some type.  This page also seems to say, at least, that shot noise formulas are not applicable to conductors. — Omegatron (talk) 23:15, 3 May 2008 (UTC)
thread_title:  Shot noise in conductors? 

message: Suppose I were taking a picture and wanted to compute the shot noise. Assuming 100% QE and FF, and no other noise, I think I'd compute the luminous intensity on each pixel (based on the luminance of the subject, the magnification, subject distance, and entrance pupil diameter), then figure out the radiant intensity at the given wavelength, then use Planck's law to get the photon flux, and multiply by the exposure time to get the number of photons. Finally, using the Poisson distribution to find \sigma = \sqrt{n}.
Does that sound right? 
If so, then if I image a candle flame at 1m with an entrance pupil diameter of 10mm so it covers 100x100 pixels, then we are talking a solid angle of 2.5×10-5 steradians. So at 1/683 W/sr at 540×1012Hz (=555nm), we are talking 3.66e-8 W. 
At that wavelength, each photon is 3.58e-19 J, so the photon flux is 1013 photons per second, or 1e10 photons for a 1/1000-second exposure, and so I get one million photons per pixel, so the standard deviation should be 1000 photons, or 0.1%.
If I throw in QE*FF=0.3 I get 0.18%, which, for an 8-bit sensor near its max looks like sigma = 0.5 counts.
Is that right? —Ben FrantzDale (talk) 15:00, 21 June 2010 (UTC)
thread_title:  Formulas for photography 

message: I don't think Schottky was the first to study shot-noise. According to the point process literatureJ. F. C. Kingman. Poisson processes, volume 3. Oxford university press, 1992.
 D. J. Daley and D. Vere-Jones. An introduction to the theory of point processes. Vol. I. Probability and its Applications (New York). Springer, New York, second edition, 2003.
, it was the workN. Campbell. The study of discontinuous phenomena. In Proc. Camb. Phil. Soc, volume 15, page 310, 1909.
N. Campbell. Discontinuities in light emission. In Proc. Cambridge Phil. Soc, volume 15, page 3, 1909.
 by Norman R. Campbell on shot noise, which was partly inspired by the work of Ernest Rutherford and Hans Geiger on alpha particle detection, where the Poisson point process arose as a solution to a family of differential equations by Harry Bateman. In Campbell's work, he presents the moments and generating functions of the random sum of a Poisson process on the real line, but remarks that the main mathematical argument was due to G. H. Hardy, which has inspired some to say that the result should be called the Campbell-Hardy theorem. Stirzaker, D., Advice to hedgehogs, or, constants can vary, The Mathematical Gazette,volume 84, page 202--203..
See  Campbell's theorem for more information.
Improbable keeler (talk) 11:52, 30 September 2013 (UTC)
thread_title:  Before Schottky there was Campbell  

message: I suspect ℏ in the formulae denotes the reduced Planck constant. Could someone confirm that and add that clarification to the text? A formula does not make much sense unless its variables are explained. The same goes for the page about the Landauer formula. --Mlewan (talk) 07:04, 22 November 2015 (UTC)
replies: text: Yes, it is definitely correct. On the other hand, I doubt that the readers who do not know what ℏ is can benefit much from this part of the article.--Ymblanter (talk) 08:27, 22 November 2015 (UTC)
thread_title:  ℏ?