Modern and Theoretical Physics

hello guys!! may be you can help me understand what's the difference (atomic interactions) between a metal spring's material & an elastic band's material and why is that the metal spring is elastic and the 'elastic' band has a plastic property?? What about the properties of amorphous solid? Stress & Strain? Merged post follows: Consecutive posts mergedguys THIS IS A TOPIC I NEED TO MASTER BEFORE MONDAY HELP !!!

Hello. I'm new on this forum, so let me first introduce my self: My name is Dejan Kober, and I'm form Croatia (South-East Europe), I'm 27 years old, and mine general occupation is 3D design, modeling and animation. And let's get to mine question... First, I want ti apologize if mine question is stupid, but I don't have any formal education in theoretical physics...... Today I have came across one video clip, witch explains multiple dimensions (10 dimensions): video clip I have to say that after watching it, I have finally manage to visualize principle of multiple dimensions... But... there is one thing that bothers me.... bending lover dimension in higher d…

To be detectable the Higgs-Boson must be at odds with what is already known.By that I mean it must be contrasted against the foreground knowledge.And not part of the landscape.If we say matter is neutral then Higgs Boson might not be.If we say matter is 3-d can we say that Higgs-Boson is 4-d?

The free physics text available on http://www.motionmountain.net (so far, the 21 MB pdf file only) has been reworked. Many improvements have been introduced throughout this 15th version of the text, which remains surprising and thought-provoking on every one of its over 1000 pages. There are many new figures, an explanation of the indeterminacy relation of thermodynamics, a new puzzle on the way to catch bananas, the fundaments of dislocations, the reason that mornings are quiet and evenings are not, the method used by whales to communicate below water, and the story on how to swim through empty, but curved space-time. The explanation of the microscope and th…

Well while reading a chapter on EM waves I got confused about EM have momentum. This really little bit confusing because momentum can only be of them who has a mass and in EM waves there nothing like mass or there isn't any thing that can have mass. So can anybody clear out my problem either I may wrong.

http://www.slac.stanford.edu/spires/topcites/2008/annual.shtml This list is informative about the research trends in high energy physics. Emphasis shifts from year to year. These are the 50 papers which during 2008 got the most citations, most references in other research publications. Papers in hot research fields tend to garner a lot of citations, so the list is a good way to identify active topics. It is especially interesting to sift out the RECENT papers on the list. What papers written in the past 4 or 5 years have attracted a lot of citations? I have to go out, but will check this as soon as I have time. Just saw it.

Let suppose we admit physics formulas represent physical reality, and we had an equation described by : Lf(x,t)=0 where L were an operator. Suppose we get a constant of integration C independent of x and t I can however write C=1 and C=2... and hence vary the constant...but if we believe t is physical time and x space, then this would contradict the fact C is a constant ....and hence C is either a function of "t" or "x" (where x is for example the position of C in the present text.....hence whole physics breaks down ??? Or do meta-time, or global time, or "experiment-intern time" (C could depend on the initial condition you could vary)...or do C depend on hidden p…

Theoretical physics is closely related to mathematics.... what is difference mathematical physics and theoretical physics ?

Solving quantum field theories via curved spacetimes Strongly interacting quantum field theories are notoriously difficult to work with, but new information about some of them is emerging from their surprising correspondence with gravitational theories. Igor R. Klebanov and Juan M. Maldacena pp. 28-33 http://ptonline.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=PHTOAD000062000001000028000001&idtype=cvips

I keep seeing ads in astronomy magaine and other popular science publications for this book written by some guy who claims that he has all the answers that all the string theories don't - he claims that his picture of reality is complete and doesn't need anything to be plugged in ad hoc, such as constants. I'm no physics expert - however such grandiose claims always cause me to raise an eyebrow. Has anyone read this book (which I think is only available from the author's website, nullphysics.com), and if so, does it stand up to critical review? Or are his claims like those of TV infomercials?

First of all, I think it's wonderful that people focus their efforts on creating theories regarding various subjects and spend time discussing about them with other people . Nevertheless, I have a qustion to pose: every day we produce several theories during our effort to understand the universe that surrounds us. Depending on our studies and our interests we elaborate on specific topics, trying to reveal some of the mysteries that "provoke"our mind. But does anyone know (and can tell the rest of us) HOW are theories produced? Many philosophers have tried to answer this question, but the answers that they have given have left me unsatisfied. Production of theories has …

What is the difference between matter and energy? Is matter a classification of energy?

Particles are some solutions of the field localized in some three dimensions and long in the last one. They prefer their long dimension to be in interior of local light cones and so they don't like to turn back. But in high energy scattering this restriction should be weakened. Shouldn't high energy scattering produce some small amount of reverse temporal momentum particles? From the perspective of our perception of time such particles would be produced before scattering, probably by the matter of detectors in accelerator. In accelerators are used extremely sensitive detectors, but they are specialized in measuring absorbed particles - they could not spot that th…

How to call symmetry between symmetry and antisymmetriy? Option 1. Symmetry (S). Option 2. Antisymmetry (AS). I think the right answer is: S-AS-S-AS-S-AS-S-AS ..... etc. I suspect that many of our questions about the World getting such oscillating answers. It look like "Liar paradox". My be it is pessimistic view? Or not, it gives dynamics to the Universe? And did him Cyclic?

I was on another forum board this night, and I was reading a post from a gentleman on a DIY projecj for a portable antenna tower for a Ham Radio antenna. One of the other people that read the post , voiced a concern over the subject of overhead power lines and lightning strikes with the use of a telescopic metal mast. Another posed the question of using a mount to go into a trailer hitch reciever, and the possibility of insulation from ground by the vehicles tires. The reply to his post gave a ton of info and links all to do with electricity and lightning and lightning strikes. There is where my question stems from. One of the bits of information that he sent, wa…

"For every action there is an opposite, and equal re-action" thats pretty much accepted worldwide as being true. as is einsteins general theory of relativity. so how do these two exist in the same world and are both accepted worldwide? where is the opposite and equal reaction in the general theory of relativity, of space or space/time pushing down on us? i say space or space/time because I dont believe in time. i never believed in gravity either long before i knew of einsteins theories and low and behold he pretty much proved me correct in not believing in gravity, therefore im pretty sure im right in not believing in "time" or at least as its perceived …

I am not quite sure if there is a theory to this subject I am bringing up, but in every science book or anything of the subject it defies this. But in a theory if you observe or even look at a model of molocules of a solid object, there is still a tiny amount of space between them. So in that thought, wouldn't that mean that somehow humans can pass through solid objects?

Not just the proton mass, but several hadrons---proton, neutron...etc. Took a year of supercomputer time. I'll get the link http://www.newscientist.com/article/dn16095-its-confirmed-matter-is-merely-vacuum-fluctuations.html "It's confirmed, matter is merely vacuum fluctuations." For simplicity, I'll focus on the case of the proton. The point is that the three quarks that make up a proton have themselves very little mass. Most of the proton's mass is somehow the result of the interaction of those three component quarks. We could always experimentally measure the proton mass, but what these people did is calculate what it theoretically ought to be (by modeling…

I understand the concept of rotational invariance but what does it mean for rotational invariance to be asymptotic in its behavior? This question comes specifically from this page: http://en.wikipedia.org/wiki/Angular_momentum#Angular_momentum_in_relativistic_mechanics

There is a big debate going on in physics at the moment about the concept of what makes a theory "natural". Clearly there are certain properties which make a theory attractive, such as its ability to describe experimental observations, it simplicity and its predictivity (i.e. how well it contrains possible realities). Naturalness is slightly more of an aesthetic concept which is why it often so controversial, but it has been used in the past and is still being used to prefer certain theories over others. Its most 'scientific' manifestation is in what is known as 'fine-tuning'. The analogy often used is of a radio station transmitting on a very narrow frequency ban…

what would the value of light be at exact point in contacting the event horizon of a blackhole?

The essential fuzziness of time may be the limiting factor for a gravitational-wave detector in Germany http://www.nature.com/news/2008/081110/full/news.2008.1217.html#B1

Since we have a thread discussing Rovelli's essay about time in physics, I thought some might enjoy this video of his talk this August at Strings-2008. Gives a good sense of what he's like and how he thinks. Packs a lot into the talk. Also gets half a dozen good questions from audience at end. Check it out. http://cdsweb.cern.ch/record/1121957?ln=en

Could the Schwarzschild metric describe black bodies instead of black holes? Perfect black bodies seem to have characteristics similar to black holes. Also Kruskal-Szekeres coordinates are interesting but I don't feel like I understand them very well. From wiki: What exactly is a coordinate singularity?

The Lightness of Being could be on its way to becoming a hit, or even a classic in the category of wide audience explanations of deep physics. It sketches out Nobel laureate Frank Wilczek's vision of a new "Golden Age" of particle physics resulting from what he expects the Large Hadron Collider to discover. This includes a view of Unified Theory coming about quite differently from how it is imagined by string theorists. The book scarcely mentions stringy theorizing and tends to be mildly dismissive of it. It strikes me as a fresh vision of the world of fundamental particles and forces---and one presented non-mathematically in what I would call individualistic and e…