Virtual Definition and 547 Threads

hi, this is about particle antiparticle pairs being produced outside the event horizon of black hole. this is what i know about it: we know that a black hole has entropy. it therefore must have temperature and hence must radiate. however, a black hole is defined as a body which pulls in...

Hi; Could someone please help me with the following question: The image of a distant tree is virtual and very small when viewed in a curved mirror. The image appears to be 18.8 cm behind the mirror. What is its radius of curvature? (Use positive for concave and negative for convex). Would I...

Perhaps it is a stupid question, but really confuses me. In QFT, virtual particles can be produced from vacuum, say, (M,0,0,0) and (-M,0,0,0) In Einstein's theory, if we consider the (-M,0,0,0) virtual particle, make it's energy-momentum tensor and solve the Einstein equation, and take the...

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I read a book and there it is written something as following: "By the lifetime of a virtual pair (e-e+) (that is given by the HUP) a virtual e- can remove with the distance s from the e+ that is given by: s=c*d(t) (d(t) from HUP)." My question: How can they annihilate if they are away at a...

While in a car on a hot day, I notice that far ahead of me is a mirror-like surface on the road. I can see the reflections in that virtual mirror too. The mirror shifts with your moving forwards. Can anyone give a simple explanation? Thanks.

Or is it just straight out of the equations? has it been detected?

I'm talking of quantum electro dynamics where we try to explain the electromagnetic "force" with virtual photons. Now an electron can "send" a photon that has more energy then it self (this photon is virtual because it can only exist because of the HUP). But spin must always be conserved. But it...

Today, I read a book which is written by Stephen Hawking. I have something don't understand. We all know that REAL TIME must go from the past to the future,but how about VIRTUAL TIME? The book says that Virtual Time can be increased or decreased in a three dimensional space. I wonder why...

I have read a bit about quantum foam and the creation of virtual particles. I understand the basic concepts, but there is one question that bothers me though: can we think of the virtual particles as just being a 'concentration' of spacetime caused by the uncertainty principle inherent in the...

[FONT=Trebuchet MS]1) What is the nature of the electric field that comes from a single charge? Do virtual particles create this field? 2) What is the nature of the coulombic interaction between charges? (I know that like charges repel and opposite charges attract. But what is the...

As we know, when we do calculations in QFT, we write down the ampitude, and find that it can be explaind as Feynman diagrams, which is easier to work out. Then we use Feynman diagrams as a tool. Now the question is, is the propagator really exists in the small distance, i.e. the Feynman...

In reviewing explanations on evaporating Black Holes using Hawking Radiation, based on how the black hole might treat Quantum “Vacuum particle pairs”. Although direct observation of Black Hole radiation has not been confirmed it implied that “Antiparticle – Particle creation, and self...

[SOLVED] virtual particles If there is createn a virtual pair (anti particle A and its particle B) in vacuum what are they doing in their life time? Is A always at the same position like B or how can they annihilate? And if they annihilate, what's with the energy (does it disappear)? Has the...

Ok, so I'm reading this book "The Age of Spiritual Machines", which is basically a book making predictions about the future of computers assuming the operation of Moore's law. Anyways, at one point, the author states something like "Around the year 2009, humans will be able to fully emerge their...

I was thinking... virtual particle-antiparticle pairs created just inside the event horizon of the universe continuously adding mass to the universe at an ever increasing rate as the event horizon expands and accelerates... How does this effect the mass/topology of the universe and could this...

Say 2 observers are moving with a constant non-zero velocity with respect to one another. Each sees the others clock running slow but since they both know about relativity they know that the other is infact aging at the same rate as they are. They just observe otherwise. To the layman this begs...

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I've got a few questions about virtual particles here. If in a vacuum, the virtual particle come in a particle, anti-particle pair. What are these particles usually? Also, is it possible that these virtual particles exert a gravitational force on an object during its short existence?? And...

if so, what would they be? virtual strings? and do they react in the same way as what we thought point particles acted? if not, then how do black holes radiate energy in string theory? also, a quick question about black holes according to string theory. Is there more than one type of black...

Why can't a negative energy virtual particle escape from a black hole? Could two sets of virtual particles arise from the same point in space simultaneously? And would they have to annihilate simultaneously? And how does a rapidly oscillating gravitational field affect virtual particle...

I could hardly believe what I read. Maybe this is common, and everybody has his own. I just discovered. :eek: :eek: :eek: :eek: Alibi If you speak french, you can already use it. Otherwise, they say they will soon be available in english, and also for Monique :-p So the story...

Hejhej, There is a religious forum where I am posting in some evolution vs. creation threads. Creationists often believe that the world and everything else has not existed much longer then several thousands years. If you ask them how to explain that the light from stars millions of light...

Can protons emit-absorb "virtual" photons? Does a free single proton behave like a free electron in the sense that it emits and absorbs "vitrual" photons as it interacts with another free or bound proton? Are there any special conditions under which protons emit and absorb "virtual" photons?

I have read some 'popular' physics and I get the impression that Electrostatic Force is caused due to transfer of virtual photons. Do these have a particular energy for a particular charge? Then they should have a particular frequency . Then if we place the charges in mediums with...

static fields - quantum picture I am trying to understand quantum field theory & QED but i am having problems, because i don't find specific answer: What is the real quantum difference between electric and magnetic field? Maybe in spin of virtual photons (1, 0, -1)? But then what is...

I'm furious with Matlab. when I reach a 1*10.000 array or similar figures it says to me: "out of memory". Does anybody know how I can do larger the virtual memory dedicated to this programe?. I have a 40 GB and 500Mb RAM computer, so it would be enough for eating anything!.

A while ago I was reading David Deutsch's book "The Fabric of Reality". Deutsch proposes that the double slit experiment is explained by the presence of large numbers of virtual photons, which leave the source, hit the wall, travel through the slits, and interfere with each other, much the...

When a vritual particle pair anihilates, does the energy radiate away in the form of gamma rays, or is it simply used to "repay the debt" of whatever energy that was borrowed to create those particles in the first place? I would assume the latter, but I would like a confirmation on that. Thanks.

Was wondering: In Hawkins's " Univers in a nutshell" book, he talks about the behavior ov virtual particle pairs around the event horizon of a black hole. My understanding is that one of the antiparticle of the pair can be absorbed by the black hole. This makes for the release of the particle (...

Was wondering: In Hawkins's " Univers in a nutshell" book, he talks about the behavior ov virtual particule pairs around the event horizon of a black hole. My understanding is that one of the antiparticule of the pair can be absorbed by the black hole. This makes for the release of the...

Can the presence of gravitational, or electro-magnetic fields cause virtual particles to arise with a preferential physical orientation? Logically, the virtual particles should not emerge in a preferred orientation if they arise spontaneously, and can't be acted upon by local fields until...

We are all familiar with the Law of Conservation of Energy: Energy cannot be created nor destroyed In other words, the total energy in a closed system is constant. But if the above "axioms" are correct, how does it cope with the existence of virtual particles? In quantum physics, events are...

One of my friend had asked me one question which I did not really have a good answer for. His question was: Why does the antiparticle counterpart of the virtual antiparticle pairs (those that appear due to uncertainty between time and energy) at the event horizon fall into the black hole...

I re-read parts of "Genius" by James Gleick earlier today after visiting a web-site that discussed steady-state cosmology. Apparently, Feinman felt that the creation and obliteration of virtual particles (diagramed by equivalent waves moving BOTH forward and backward in time) supported the idea...

http://www.newscientist.com/news/news.jsp?id=ns99994807

Seems to me that in deep space real photons collide often with virtual particles. Is that a reasonable theory? If so, what are the (approximate or ball-park) statistics? What does happen? Does the putative virtual particle involved in a collision with a real photon become real? What are the...

Suppose two particles bound by electromagnetic interaction, kind of hidrogen atom. How do you calculate the number of virtual photons exchanged by unit of time? Has this frequency of exchange some meaning in usual textbooks?

Hi everyone! Time has come for my first thread in this nice forum: I wonder if someone could explain the concept of virtual photons (and virtual particles in general)? Have I understood it right that they are just a mathematical construction and are not in any way "real"? I have a lack of...

hey, all i'm now studiynd analytical mechanics and the subject is Langrange equations. What i can't grasp is the meaning of virtual displacement term. The formal definition says that: it's a small displacement of particle with agreement to constraints in such a way that no time passes...

A Virtual Scanning Electron Microscope, the link is provided to me (and anyone who reads that Journal) by the People at the Journal Science, The AAAS... Click http://www.vcbio.sci.kun.nl/eng/fesem/"

my name is cory mccall and i live in spf mo. i am a junior in high school who is extremely interested in the fields of theoretical nuclear particle and astrophysics. for the first year I am going to submit a project to the science fair. over the course of about a month I am goin to be throwing...

Ok so if you can't see it then how do you really know anything about the effect or behavior on the unmeasured side? Isn't this dependent on the particular interpretation used, such as the Copenhagen Interpretation for instance? I mean what really is the "collapse of the wave function"...

The issue arises whether virtual particles can be considered to be "real" in the same sense that photons of light can be. So exactly when is a photon real and when is it virtual, and do virtual photons have as much right to be thought of as existing as "real" ones? A real photon (free field...

Are virtual particles entangled when they appear? If so then when one of the pair falls into a black hole and other flies off, do they remain entangled? If so, does this mean that by observing black hole radiation we can in principle 'see inside'?

Let say I have an installation CD of Microsoft office, which can autorun. How can I create a virtual CD on my hardisk , copy the whole contents of the CD onto my HDD. When I double click the virtual CD, it can autorun; and, I can also burn it onto a blank CD, duplicate it. What software...

I know that the escape velocity for virtual particles being emitted from black holes is c2+ (in the black hole entropy formula, there is an escape velocity of c3). I also know that Hawking radiation and for that matter*(I don't mean matter in physics terms), any radiation being emitted from a...