excited!

[meridannight]

i know this is really irrelevant to everyone on here, but i don't care, i wanted to share i just started a course on quantum physics. i am so excited about it! it's one of the disciplines that really took me by storm when i first discovered it (which was years back in flight school). i've been fascinated by it ever since.

Victor Galitski is one of the instructors (University of Maryland). he's currently one of the top researchers in quantum physics, and his research is funded by US Army, among others.

this course will involve a lot of math that will go way over my head right now, lol. i only have introductory college physics under me (aside from aerospace engineering sciences), and nothing too involved. i will probably not pass this one, but i don't even care! i need exposure to it, and i want to just learn as much as i can.

this is really exciting to me. makes me smile. can't wait!

[meridannight]

P.S. if you haven't heard of it, there's this site:

https://www.coursera.org/

through that site you can take all kinds of college courses for free. (if you want a verifiable certificate to your name, then it costs a little, but you are not required to get that, and the cost really is minimal). there are courses on science, business, philosophy, art, history, etc etc. from universities like University of Chicago, Duke University, John Hopkins, etc. most colleges are in the US and EU. some of the professors are well-known and accomplished in their field.

it's fully online, you can study on your own terms. on some courses there's even no time limit (i.e. no deadline by which time your tests/exams need to be completed), you can go at your own pace, take a whole year, if that's what you want on those. others last a certain amount of time (usually 8-10 weeks) and tests have deadlines.

i've already taken courses on neuroscience and astrophysics there. there's people all over the world. and the best part is -- it really works. it's college education brought to your home.

if you're at all interested you should check it out. you might find something to your liking.

[MikeW]

One thing I'd appreciate is if you'd post in this thread some of what you're learning as you learn it. Ummm… if you can dumb it down for those of us who have no math skills at all! I've read in the general area (for lay people) years ago but have forgotten a lot of what I read.

[meridannight]

One thing I'd appreciate is if you'd post in this thread some of what you're learning as you learn it. Ummm… if you can dumb it down for those of us who have no math skills at all! I've read in the general area (for lay people) years ago but have forgotten a lot of what I read.

of course i can. i didn't expect there to be any interest. but it will serve me as well, to try to rephrase/sum up the things i learn about. and it's an exciting subject for me, and i like to talk about it (i've tried this in real life before, lol).

you don't have to worry about math. most of that will go over my head. i wasn't kidding about that. (i have Galitski's textbook at home, and it's insane: Galitski).

i need to do a serious brush-up on my mathematical skills before i can get involved with the subject on that level, although i do want to get there eventually. but this course is offered right now and i'm not gonna let the opportunity pass.

[MikeW]

of course i can. i didn't expect there to be any interest.

Well, it probably won't be a HOT topic, like whether or not Amy Vanderbilt would approve of dining on the divan, but, hey, i'm curious why Schrödinger wants to torture cats! Such a meanie!!

[Wolfpack]

Awwww really pleased for you, it is nice to be so passionate about something, enjoy your course.

[meridannight]

before we get to the more fancy implications involved in q.m. (like Schrödinger's cat), i'd like to bring out one of the basic things, and why we even have quantum mechanics.

one of the most important things to keep in mind is that a light can behave like a beam of particles, and particles can behave like waves. all of this has been experimentally verified, and classical mechanics cannot provide an explanation.


the thing with the Schrödinger's cat is that it implies that by observing/detecting/measuring something we are, in fact, changing the thing/process in some essential way. the cat ''experiment'' was devised as a thought experiment to illustrate the Copenhagen interpretation.

essentially, when we want to learn about something unknown to us, upon doing our measurements we are changing the very thing we want to study (it is said that the wave function collapses upon measurement). in the cat thought experiment this means that in the box, the cat is both dead and alive, and it is only when we open the box to look (or try to obtain the value through other measurements) that the reality materializes. (bear in mind that a cat is a macroscopic entity and this ''experiment'' cannot be devised on any cat. cat is supposed to represent microscopic elements (like an electron) to which quantum mechanics applies).

this was also revealed when they shot electrons at a screen that had slits in it (the double slit experiments). they shot one electron at the screen at a time. the amazing result was an interference pattern! this implies that one electron somehow went through both slits at the same time and interacted with itself to create an interference pattern! (Feynman) (this is AMAZING! truly one of the most fascinating things ever discovered). this could only happen if the electron is a wave and not a particle, like we're used to thinking.

they then added a detector to determine through which one of the slits the particle actually went through. but, now the interference pattern vanished! electron went through one of the slits, and one only, and behaved like expected of a particle. the measurement changed the outcome.

so, in conclusion, light (energy, wave) can sometimes behave like it's particles, and the reverse is true – particles can sometimes behave like waves (all matter exhibits both wave and particle properties). and that human measurement changes the result. this is true in case of the microscopic scales of the universe, to which quantum mechanics applies.


P.S. one of the most fascinating implications in quantum mechanics is that every electron (or any other microscopic particle) in the universe appears to ''know'' what all the other electrons are doing at all times.

P.P.S. even something as simple as a proton, for example, does not have a stable inner structure. in fact, its inner structure is in constant change and much more complex than three quarks.

(i just wanted to mention these two, as they are incredible mind-expanding realizations).


-------------------------------
recommended reading:
[COLOR="DeepSkyBlue"]Don Lincoln -- Understanding the Universe from Quarks to the Cosmos
Brian Greene -- The Elegant Universe[/COLOR]

[meridannight]

and i just have to share this quote from Brian Greene's book regarding the double slit experiment:

Feynman argued that in traveling from the source to a given point on the screen each individual electron actually traverses every possible trajectory simultaneously. it goes in a nice orderly way through the left slit. it simultaneously also goes in a nice orderly way through the right slit. it heads toward the left slit but suddenly changes course and heads through the right. it meanders back and forth finally passing through the left slit. it goes on a long journey to the Andromeda Galaxy before turning back and passing through the left slit on its way to the screen. the electron, according to Feynman, simultaneously ''sniffs'' out every possible path connecting its starting location to its final destination.

how do you NOT get fascinated about this!!

[MikeW]

Ok, don't be mean to me if I ask a truly dumb question.

One thing that has always bothered me is the notion of a "charged particle"… Why "particle" at all? Why not just a "charge"?

IOW, if there is no "particle" but only a "charge" then why would we expect it to NOT behave much like a "wave"?

Where I'm coming from is the sense that sub-atomic physics (about which I know virtually nothing) has always seemed to visualize these "billiard ball" things. But that's not what we have, is it? What we have are "fields," right? So, like what you're saying with your second PS above, a proton isn't an "object" it is a field in motion that has within it something we're calling "quarks." Alright, so under high-energy collision these "quarks" seem to scatter in observably different ways… but what are we really talking about here? They are surely not "objects," right, any more than an echo is an object?

[meridannight]

[MENTION=20947]MikeW[/MENTION], i'm way past my bedtime, and i'm only gonna address this right now: it's because the elementary particles (and even smaller molecules, actually) behave both like a wave and a particle (which is NOT wave). they are definitely particles, but they are also waves. both. but not both at the same time. <---this little part is the crucial part here to understand. (and the wave associated with them is the probability wave).

i want to get back to you on the rest of your post, but i'll do it tomorrow.