Trmwiki

Welcome

Latest comment: 13 years ago4 comments2 people in discussion

Hi Trmwiki,

I see no one has welcomed you yet, so I guess I'll leave you the standard welcome template. (Feel free to delete if you don't like templates.)

Welcome!

Hello, Trmwiki, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are some pages that you might find helpful:

I hope you enjoy editing here and being a Wikipedian! Please sign your messages on discussion pages using four tildes (~~~~); this will automatically insert your username and the date. If you need help, check out Wikipedia:Questions, ask me on my talk page, or ask your question on this page and then place {{helpme}} before the question. Again, welcome! Zaereth (talk) 02:15, 4 October 2011 (UTC)Reply

I noticed your addition to the diffraction grating page, and it does sound like an interesting take on diffraction. I'm not sure I fully grasp the concept. However, if you don't mind, I may offer a bit of insight on improving the readability. This is not meant to be critical, but are merely suggestions based on my past experience.

It might help to separate the different ideas presented in the text into different paragraphs. For instance, the first two sentences would seem to make a good introduction paragraph. I would probably make the next paragraph break between sentence 7 and 8, and so on. Of course, because you obviously understand the material better than I, you may decide there are better places to break.

Try to avoid beginning sentences with conjunctions, such as "and," "but," "so," or "now," or phrases like "in short." It's just not necessary. I would also avoid explaining the punctuation. Most reader will understand the meaning of quotation marks. I'd try to avoid phrases like "of course" "we" or other things that put the writing in the first person rather than the third.

Look at statements in parentheses very carefully, and determine if the information is really necessary. Usually, just by placing something in parentheses, it indicates that on a subconscious level, you may think it interesting, but not really necessary. If not needed, simply cut, but if needed, then consider using commas, periods or conjunctions instead.

Other than those minor things, the writing looks very professional. If I were to make these changes myself, it would probably look something like this:

QED (quantum electrodynamics) offers another derivation of the properties of a diffraction grating in terms of photons as particles. QED models photons as following all paths from a source to a final point, each of which has a certain probability amplitude, which can be represented as a vector or complex number (equivalently), or as Richard Feynman simply calls them in his book on QED, "arrows".

For the probability that a certain event will happen, one sums the probability amplitudes for all of the possible ways in which the event can occur, and then takes the square of the length of the result. The probability amplitude of a photon from a monochromatic source, in this case, is modeled as an arrow that spins rapidly until it is "evaluated" at its final point. This spinning is actually dependent on the time at which the photon would have left the monochromatic source, as the probability amplitudes of photons do not spin while they are in transit. For example, for the probability that light will reflect off of a mirror, one sets the photon's probability amplitude spinning as it leaves the source, follows it to the mirror, and then to its final point. One then 'evaluates' it at the final point; next, one sums these arrows in a standard vector sum, and squares the length of the result for the probability that this photon will reflect off of the mirror. The times these paths take are what determine the angle of the probability amplitude arrow, as they 'spin' at a constant rate (which is related to the frequency of the photon).

The times of the paths near the classical reflection site of the mirror will be nearly the same, so as a result the probability amplitudes will point in nearly the same direction—thus, they will have a sizable sum. Examining the paths towards the edges of the mirror reveals that the times of nearby paths are quite different from each other, and thus one winds up summing vectors that cancel out quickly. There is a higher probability that light will follow a near-classical reflection path than a path further out. However, a diffraction grating can be made out of this mirror, by scraping away areas near the edge of the mirror that usually cancel nearby amplitudes out but, now, since the photons would not reflect from the scraped-off portions, the probability amplitude pointing, say, to the right can have a sizable sum. Thus, this would let light of the right frequency sum to a larger probability amplitude, which then has its length squared for the probability that light will reflect from the selected region.

This description involves many simplifications: a point source, a "surface" that light can reflect off of (thus neglecting the interactions with electrons) and so forth. However, this approximation is a reasonable one to illustrate a diffraction grating conceptually. Light of a different frequency can also use the same diffraction grating, but with a different final point.[1]

Once again, these are just suggestions, and you can feel free to ignore them if you like. If you're new, and I can help you out in any way, please let me know. I've been here long enough to be able to point you in the right direction. Zaereth (talk) 02:15, 4 October 2011 (UTC)Reply

Zaereth,

Thank you so much! Yes, I am new here, and really appreciate your comments, many of which I've just now incorporated into the article. You've given me a great introduction to Wikipedia 'formalism', if you will. So thanks. I'll continue to edit over time, hopefully finding the time to include images in this particular entry to improve understanding. In the meantime, thanks again for taking the time to notice this and help me out! Trmwiki (talk) 04:43, 4 October 2011 (UTC)Reply

No problem. I'm always happy to help, but I'm also a busy person and only spend a few minutes a day doing this, so don't be surprised if I don't respond to questions right away. One policy Wikipedia has is to simply be bold. If you have information that seems useful to you, go ahead and insert it into an article. As long as you provide a source, and the information matches the source, people will rarely revert it. If the do, just start a discussion on the talk page. The writing does need to be original --in your own words-- so that no copyright laws are violated. Personally, though, I like to bring up major changes on talk pages before hand, much like you did.

There are tons of policies on just about everything you could imagine. Aside from the WP:Bold, revert, discuss policy, some of the main ones are WP:Verifiability, WP:Reliable source, WP:Neutral point of view, WP:No original research, and WP:Notability. To simplify, as long as your additions are notable and verifiable in a reliable source, contain no original research (ie:someone else researched it and, preferably, a third party wrote about it), and is written in a neutral point of view (ie:third person, no hype, dispassionate tone), you should have little problem here.

Also, when you leave a comment on a talk page, it is helpful to sign your posts. A bot will sometimes come along and do this for you, but not always. This helps other to tell who is saying what. Simply typing four tildes, (~ the little squiggly line near the top right of your keyboard), will insert your name automatically.

Another thing you may notice is that when you edit a page, at the bottom of the edit screen is a place to leave an edit summary. This is a small description of the changes you have made. This shows up on people's watchlists, and saves a lot of time for people who are just watching for vandalism, spam, or other nonsense. For instance, my edit summary for this edit will show up on your watchlist as "r," for response. Sometimes "cmt" for comment, typo, etc... However, use more detail when describing any large changes. Near the top of any article is a tab with a star on it. Simply click this to add the article to your own watchlist.

I hope that helps. Zaereth (talk) 20:10, 4 October 2011 (UTC)Reply

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