Virtual Definition and 565 Threads

Hello Just had a quick question for a structures class. When attempting a problem, what's the main difference between applying PVW and PMPE? What would classify a problem in using one over the other? Thanks

a) Two protons, approaching each other with 3keV of energy each, collide head on. Calculate how close they get to each other. b) Estimate the momentum transferred by one virtual photon at the closest approach. c) Hence, estimate roughly how many virtual particles are exchanged during the...

Can anyone provide it? I just examined wiki article just for fun, it is a mess of different concepts (because, as I understand, there was an attempt to make it interpretation-neutral) So, can anyone provide a definition which is MWI-compatible? For example: in MWI any 'particle' behavior...

Okay... In the quantum world, is all motion absolute? As in, can you pinpoint whether or not a particle is actually moving using space as a reference point? Or is it like in general relativity where the only motion that matters is motion relative to other particles? If it is like the model...

Hi all, I have (what might be a rather odd) question about the interactions between real and virtual particles. Let's say we have an isolated proton, moving slowly through space. There will be virtual proton/anti-proton pairs popping in and out of existence in the surrounding space. On...

Dear All, I have got a subclass (Panda), which inherits a Print function from the base class (Bear). I'd like to be able to call the base class's function from the subclass. But my complier gives me the following error message: In member function `virtual void Panda::print(char)'...

Does anyone have a suggestion on how to set up a virtual window in a windowless room (or office or shop)? Google search came up with some kind of Apple or Wii set-up, has anyone tried it? Have comments on it? Does anyone have other suggestions? [Mod: please feel free to move under Tech or...

Hi folks, I have a question that I so far haven't been able to locate an answer to - it's mostly for curiosity. If virtual particles are continually popping in and out of existence in the vacuum, why do they not produce a frictional force on objects moving at constant velocity through...

In an convergent/divergent lens, how do we consider an object real o virtual?? I thonk is real if it's placed at left of the len and virtual if at right. Right?

I was having a conversation with a physicist on Facebook (author of a book I rather enjoyed - "Users guide to the universe"), and he let the conversation end without my question ever being fully answered. Perhaps someone here can help explain this to me. I'll paste the entire conversation...

What do you think? I thought a poll, just for the fun of it!

If virtual particles pop into and out of existence in less than the blink of an eye, 1. How much less than a blink...less than 10-43 seconds? 2. Where is this happening now as I speak..in front of my eyes, in my next door neighbor's house, or in places far far away..? 3. If some of these...

I don't understand what's meant by 'images can be caught or cannot be caught on a screen?'. Can we catch the pictures which are not live only?

Homework Statement A virtual memory system has a page size of 512 bytes, seven virtual pages, and four physical page frames. The page table is as follows: VPN...PFN 0.....2 1.....0 2.....- 3.....1 4.....3 5.....- 6.....- Note: VPN -> Virtual Page Number, PFN -> Page Frame Number...

How are virtual photons and virtual electron-positrons pairs of the polarized vacuum related? Are they interchangeable, do virtual pairs give rise to virtual photons? Or none of the above?:)

Hi Everyone I was wondering if virtual particles travel faster than light,i ask this because i saw a video where it talks about virtual particles traveling faster than light but if that is...

Virtual Particles appear due to the Weisenberg Uncertainty Principle. So if \Deltat is prolonged or something like that, virtual particles become real. Am I right?

Please teach me this problem: The classical field of real photon obey Maxwell equations,so the speed of light is c=1,therefore real photon is massless particle.But I think virtual photon maybe not obey Maxwell equations because virtual particle is the fluctuation of vacuum.So maybe virtual...

I could not understand the Principle of virtual work. Suppose we have two (x,y,t) [at two different points].By principle of least action we will get a trajectory such that it minimize lagrangian. Does the principle of virtual work say that it will vary the path a little but having the same...

hi, let's suppose 2 electrons are far away each other and therefore they interact very weakly. i wonder if in such case there are as many virtual photons in the case they are very close to each other? because i know that only 1 electron in complete vacuum generates an electromagnetic field and...

i wonder whether an electron is absorbing virtual photons because it is in a electromagnetic field, would that mean that it would change its angular momentum by hbar?

Hi guys, it's been a long time since I wrote here the last time... I come with a very stupid question... it's only a definition, and it's a matter of ignorance I know that... but nobody ever explained it to me, nor i ever found a clear definition on a QFT book... or probably I simply don't...

On Ask The Experts which is a cool new site for technology enthusiasts, there is an article in its ATE Defence Space and Aerospace which looks at the what can be derived and achieved when virtual engineering is applied to the aerospace industry http://tinyurl.com/39q2eqh its suggestions are...

rigorous statement of virtual work principle?? in the texts on mechanics the virtual work principle is always stated in 'infitesimal form'. is there a "proper" way to write the principle of virtual work in which we don't leave it in terms of INFINITESIMALS.

I am trying to find out RPM and torque of a turbine. I have it modeled in CATIA. I have ansys and Fluent. But I don't know if I can get these values from that software. Does anyone know how I can do a virtual simulation to determine Torque and RPM?

In my textbook, "Universe" by Friedman et al it says the following: "During inflation, however , the universe expands so fast that particles were rapidly separated from their corresponding antiparticles. Deprived of the oppurtunity to recombine and annhilate, these virtual particles became real...

Do virtual particles break the conservation laws? Thanks

I suppose that momentum of virtual photons is known precisely and energy of them is uncertain. But how uncertain? Maybe let us look the simplest example: scattering on heavy nuclei. Or, there are some more simple examples as scalar photons.

hi, when an electron stays in the same electronic orbitals with principal quantum number n, with a constant energy and momentum, are there still virtuals photons that are permanently exchanged between this electron and the nucleus? I believe that the electromagnetic field is equivalent...

I’ve got few simple questions (and views) about which I’m pondering on for some time now and since I’m layman on these topics I’d love to hear thoughts and insights about them from some of the great contributors at this forum. Thank you! -- Is gravity in center of star highest, lowest or...

Effing Virtual States -- How do they work? I want to talk to a scientist because this is pissing me off. >:-( So, I'm learning about CARS and Raman spectroscopy. Since Day 1 of Modern Physics I've been told that atoms have discrete energy levels and only the only way to get an electron from...

Virtual photons are not "observed" because they have a deficit of energy. When they are emitted from particles momentum is conserved but energy is not conserved. The deficit of energy is accommodated with the uncertainty relation: delta_E * delta_t of the order of h_bar Now if delta_t...

In quantum renormalization, one distinguishes between the (unobservable) bare electron and the observable properties. The justifications that I can find for the procedure seem to rest purely on mathematical and empirical grounds: the methods are in line with a consistent mathematical theory...

Hello! Is it true that virtual particules pop into existence uncaused? thank you

i want to throughly understand the principle of virtual work. why this principle was invented? "sum of work done by forces is zero". such a definition is very vague for me. can anyone explain?

Virtual particles confuse me a bit, because although the ones which exist for such short times in Feynman diagrams seem straightforward, the electric and magnetic forces, whose ranges are infinite, are transported via virtual particles, whereas a real photon is just electromagnetic radiation...

Hi, I don't know how many of you have played around with virtual desktops either in Linux or Windows environments. I realize that most virtual desktop software for Windows displays only one desktop on the monitor at a time. I am wondering whether or not it's possible to get one or...

Before Posting This , I spent nearly an entire day googling the problem of virtual particles and the conservation of energy , but it only got me more confused :confused: Let's review this problem from the beginning : Due to Heisenberg's uncertainty relation between time and energy \Delta t...

So virtual particles are allowed to exist so long as they 'give back' their energy in the time alloted by the uncertainty principle. This might be a fairly naive question, but it occurred to me that maybe the opposite is true. Can 'real' particles cease to exist for brief flashes of time without...

Im new and not that advanced in science so can you try to keep your answers simple. My question is can virtual particles break the law that energy cannot be created or destroyed? Have virtual particles been proven/observed? thanks in advance for your answers

Homework Statement anyone guide me step by step how to use virtual work method to calculate all reactions on this beam? thanks Homework Equations The Attempt at a Solution

Hahaha, yeah I did a search on these forums for questions regarding Virtual Particles and it seems its "the horse that's been beaten to death with a stick". But, I still have questions so please try and answer them because the people on there are much more versed than me in physics. I am a...

1) In non-mathmatical terms, please correct my description of vitual particles... a) virtual particles are real but too small to be observed directly. i.e. their dimensions are within Plank's values and subject to Heisenberg's uncertainty principles. b) virtual particles are real...

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Is there a way to calculate the wavelength, frequency or energy (per photon) of the virtual photons that charges exchange to account for the Coulomb force? This is assuming that it's always the same wavelength, of course.

If there is a 1024x1024 array of 32 bits numbers and we need to normalize by columns. Algorithm goes through each column, finds max and divide all numbers by the max. It would be certainly wise to store the pages by column? My rationale: 1M (2^20) main memory is allocated and each...

Homework Statement The virtual image produced by a convex mirror is one-quarter the size of the object. b) What is the focal length of this mirror? Homework Equations 1/di = 1/f - 1/do The Attempt at a Solution i found di to be -9.3 cm but when i solved for f i keep getting it...

using the principal of virtual work, find the reactions of the following structure as far as i know, to solve using virtual work i take the statically determinate structure and release one of the support reactions making it indeterminate (1st degree), after picking my brain with the...

I have two questions: 1. Wikipedia defines the will to live as "a psychological force to fight for survival, particularly when one's life is threatened by an injury or disease such as cancer." Have there been any experiments or studies done showing that a conscious decision by an individual...

A few years back, you couldn’t open any newspaper, magazine or law review journal without seeing yet another article about the crazy things that were going on in virtual worlds. *Today, not so much. *News of the*closure of Metaplace didn’t even make it very far beyond the usual VW blogs… *So...