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Topic: Virtual particle

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  Virtual particle - Wikipedia, the free encyclopedia
The concept of virtual particles necessarily arises in the perturbation theory of quantum field theory where interactions between real particles are described in terms of exchanges of virtual particles.
As such, virtual particles are also excitations of the underlying fields, but are "temporary" in the sense that they appear in calculations, but never as indexes to the scattering matrix (i.e., they never appear as the observable inputs and outputs of the physical process being modeled).
In the later case, it is sometimes said that virtual particles cause the effect, or that the effect occurs because of the existence of virtual particles.
en.wikipedia.org /wiki/Virtual_particle   (1617 words)

 Virtual particle -   (Site not responding. Last check: 2007-10-21)
In physics, a virtual particle is a loosely defined term that is frequently used to explain or illuminate a variety of disparate effects in quantum field theory.
As such, virtual particles are also excitations of the underlying fields, but are "temporary" in the sense that they appear in calculations, but never as indexes to the scattering matrix.
Formally, a particle is considered to be an eigenstate of the particle number operator a^\dagger a where a is the particle annihilation operator and a^\dagger particle creation operator (sometimes collectively called ladder operators).
psychcentral.com /psypsych/Virtual_particle   (1322 words)

 "W" Particle and the Weak Force "IVBs"
The IVBs are particles of interaction only - they are metric catalysts, mediators, or "brokers" which allow and facilitate transformations and decays within and between the "families" of elementary particles, the quarks and leptons, which are respectively the constituents of the nucleus and the electron shell of atomic matter.
The energy to produce these virtual particles must be borrowed from the vacuum surrounding their point of manifestation, and this energy must be paid back to the vacuum before its loss is "noticed" by the "police" - the conservation laws - particularly the conservation of energy.
The large mass of the W IVB is interpreted as a measure of the extreme proximity required by the transfer mechanism (the greater the proximity, the higher the energy required to force the partners together, and hence the greater the necessary mass of the IVB).
www.people.cornell.edu /pages/jag8/sect4.html   (3724 words)

 Creation ex nihilo - Without God
[Virtual particle pairs] are predicted to have a calculable effect upon the energy levels of atoms.
The forces and particles that appear are more-or-less random, governed only by symmetry principles (like the conservation principles of energy and momentum) that are also not the product of design but exactly what one has in the absence of design.
We just happen to be in the one where the forces and particles lent themselves to the generation of carbon and other atoms with the complexity necessary to evolve living and thinking organisms.
www.infidels.org /library/modern/mark_vuletic/vacuum.html   (1727 words)

 virtual pair Comparison Table   (Site not responding. Last check: 2007-10-21)
Quantum uncertainties in energy make it possible for virtual particles to be constantly created and annihilated during elementary particle interactions.
Elementary particles are able to make use of these virtual particles within their interactions.
Particle and antiparticle that exist for an extremely short time, often as the intermediate stage of a nuclear transition.
www.site.uottawa.ca:4321 /astronomy/virtualpair_table.html   (97 words)

 Anatomy of the Star Goddess: Quantum Cosmology, Virtual States, Energy Science, and Scalar Fields
Particles can be destabilized by such subliminal thoughts as "I am a bad person, and deserve punishment." Core issues like this can lead to thought patterns which de-stabilize systems in the body and lead to a diversity of diseases ranging from those described as psychosomatic to those which pronounce a death-sentence, such as cancer.
Thus the vacuum is viewed as a seething inferno of virtual particle fluxes, and the concept of an ether is again accepted as referring to this "virtual plasma" or "virtual flux" vacuum -- which is a far different ether than the old material ether that was theorized prior to relativity.
Many other sorts of virtual particles are emitted and absorbed and born and extinguished, in addition to photons, by various observable particles in free space.
zero-point.tripod.com /stargoddess/anatomy.html   (17499 words)

 Virtual Particles and Other Weirdness
It is trur therefore that a virtual particle is al;most the same as a true particle.
As we discuss virtual particles and the quantum dimension, you will notice that their quantum effects really could be a non-physical channel for the wave information of Nick Herbert’s “quantum stuff”.
Since the quantum virtual particles are in the tissues of our brain in great numbers, it seems that our thoughts and activities are impressed instantly in that area of quantum information.
home.infionline.net /~jforberg/id10.html   (2334 words)

 Exchange Forces
The maximum range of an exchange force is dictated by the uncertainty principle since the particles involved are created and exist only in the exchange process - they are called "virtual" particles.
If a force involves the exchange of a particle, that particle has to "get back home before it is missed" in the sense that it must fit within the constraints of the uncertainty principle.
A particle which can exist only within the constraints of the uncertainty principle is called a "virtual particle", and the time in the expression above represents the maximum lifetime of the virtual exchange particle.
hyperphysics.phy-astr.gsu.edu /hbase/forces/exchg.html#c1   (565 words)

 [No title]
II Building a virtual particle with vertex constraints Equations defining the virtual particle The motion of a charged particle in an arbitrarily oriented, fixed magnetic field was described in Appendix II in ref. [1].
III Building virtual particles when a subset of particles is verticized Building virtual particles is more complicated than discussed above because we want the flexibility of merging different kinds of particles, some of which have poor or no position information and so cannot be easily used in a vertex constraint.
Particles which are forced to pass through the vertex determined by the first class, but which are not used to find the vertex.
www.phys.ufl.edu /~avery/fitting/virtual.doc   (2498 words)

 Re: Can real particles be changed to virtual particles?
virtual particles are particles that cannot be detected.
the heavier virtual particles are the shorter is the reach of the interaction propagated by these virtual particles.
virtual particles can not be transformed into real particles, virtual particles can be absorbed by real particles, and then something happens to that particle.
www.madsci.org /posts/archives/mar2001/985879680.Ph.r.html   (343 words)

 Some Frequently Asked Questions About Virtual Particles
Now, consider a virtual photon that comes from the particle on the right and is absorbed by the particle on the left.
This is because of the propagation of virtual quanta of the F field, represented by the diagonal lines.
The notion of virtual particles mediating static forces comes from perturbation theory, and if there is one thing we know about quantum gravity, it's that the usual way of doing perturbation theory doesn't work.
math.ucr.edu /home/baez/physics/Quantum/virtual_particles.html   (3494 words)

 The "W" Particle and the Weak Force Mechanism
An IVB "metric particle", mediator, or catalyst functions by engulfing a particle ripe for transformation (referred to below as the "parent" particle), and combining it with one or more suitable particle-antiparticle pairs, these latter drawn from the infinitely varied resources of the virtual particle "sea", the quantum fluctuations of the vacuum.
Because the real and virtual particles of today were once all part of the same primordial high energy "sea", it appears that the IVBs are simply reconnecting the manifest and unmanifest parts of the original "sea" by reconstituting the dense metric in which both were born.
Hence although the virtual particle x antiparticle complex is identical in both the "short" and "long" decay sequences, the products are different because the "short" annihilates one member of its virtual complex, whereas the "long" does not.
www.people.cornell.edu /pages/jag8/weakforce.html   (3265 words)

 ipedia.com: Virtual particle Article   (Site not responding. Last check: 2007-10-21)
In the description of the interaction between elementary particles in quantum field theory, a virtual particle is a temporary elementary particle, used to describe an intermediate stage in the interac...
Virtual particles always come in pairs, a particle and antiparticle, which can be of any kind.
In quantum field theory the number of particless in an area of space is not a well-defined quantity, but like other quantum observables is represented by a probability distribution.
www.ipedia.com /virtual_particle.html   (394 words)

 Some Frequently Asked Questions About Virtual Particles
It's hard even for particle physicists to see this using the Feynmandiagram rules of QED, because they're usually formulated in a mannerdesigned to answer a completely different question: that of theprobability of particles in plane-wave states scattering off of eachother at various angles.
Here, though, we want to understand whatnudges a couple of particles that are just sitting around somedistance apart--to explain the experiment you may have done in highschool, in which charged balls of aluminum foil repel each other whenhanging from strings.
Now, consider a virtual photon that comes from the particle on theright and is absorbed by the particle on the left.
johnoleary.net /cones/virtual_particles.html   (3224 words)

 Learn more about Virtual particle in the online encyclopedia.   (Site not responding. Last check: 2007-10-21)
Learn more about Virtual particle in the online encyclopedia.
Virtual particles are always created as a pair of particle-antiparticle, and mutually annihilate in short order.
This is the process by which fl holes evaporate.
www.onlineencyclopedia.org /v/vi/virtual_particle.html   (331 words)

 Question: What is Virtuality for a Virtual Photon?
Virtual particles arise because in QFT, the conservation of total energy can be violated for a very short time, thanks to the HUP.
The technical definition of virtuality is just the amount by which the particle is off it's mass shell.
For a massive particle this would be modified to be "virtuality = Q^2 - m^2", where m is the mass of the particle.
www.physicsforums.com /showthread.php?p=977991#post977991   (629 words)

 virtual particle concept from the Astronomy knowledge base   (Site not responding. Last check: 2007-10-21)
has definition Particles that erupt from the vacuum momentarily; they exist on borrowed energy, consistent with the uncertainty principle, and rapidly annihilate, thereby repaying the energy loan.
has definition Quantum uncertainties in energy make it possible for virtual particles to be constantly created and annihilated during elementary particle interactions.
virtual pair (2 facts) - Particle and antiparticle that exist for an extremely short time, often as the intermediate stage of a nuclear transition.
www.site.uottawa.ca:4321 /astronomy/virtualparticle.html   (197 words)

 Unfounded Conclusions
Thus, the momentum associated with a virtual particle can be exchanged no matter the physical location of the two particles between which the exchange takes place.
If the particles are sufficiently far enough apart, the virtual particle that travels between them appears to move faster than the speed of light.
The result is that the particle which receives the virtual particle appears to affect the transmitting particle backwards in time.
www.angelfire.com /ga/dracodraconis/physicsconcl.html   (413 words)

 Halfbakery: Faster Than Light
The idea here is to decrease the number of virtual particles with which photons interact, and that naturally means that the rate of interaction must also decrease, on a per-unit-of-distance basis.
virtual particles are not the ones to be concerned with...
Thus, with no virtual particles in a vacuum, there is nothing to stop the particle-like properties of a photon from being sufficient for it to cross the vacuum.
www.halfbakery.com /lr/idea/Faster_20Than_20Light   (7879 words)

 Particles, Special Relativity and Quantum Mechanics   (Site not responding. Last check: 2007-10-21)
Any particle with mass m is constrained to move on the upper branch of this hyperbola.
In the quark model, there are only 12 elementary particles, which appear in three "generations." The first generation consists of the up quark, the down quark, the electron, and the electron neutrino.
The Standard Model of particle physics also predicts the existence of a "Higgs boson," which has to do with breaking a symmetry involving these forces, and which is responsible for the masses of all the other particles.
atschool.eduweb.co.uk /rmext04/92andwed/pf_quant.html   (8959 words)

 High Energy Physics Sites
There are rather severe limitations to this approach, but it's a worthy attempt to share some of the results of the enterprise that is particle physics with the general public and students.
This is the real thing: the Particle Data Group maintains and organizes the storehouse of data accumulated by the world's particle physics labs in the past few decades.
Particle physics experiments are hard to do in a classroom, but you can show your students the real tracks of cosmic rays or particles from nuclear decays in the diffusion cloud chambers sold by Supersaturated Environments.
www.onscreen-sci.com /HEP_sites.html   (874 words)

 The Force of Empty Space
This 200-µm-diameter sphere mounted on a cantilever was brought to within 100 nm of a flat surface (not shown) to detect the elusive Casimir force.
According to quantum mechanics, the vacuum is not empty, but teeming with virtual particles that constantly wink in and out of existence.
The simplest explanation of the Casimir effect is that the two metal plates attract because their reflective surfaces exclude virtual photons of wavelengths longer than the separation distance.
focus.aps.org /story/v2/st28   (670 words)

 real photon - virtual particle collisons
Well, a virtual particle is a particle whose momenta is not relate to its energy.
This is a violation of energy preservation, thus the virtual particle can only exist a very small time h/E; during this time the uncertainty principle "covers" the crime.
Other possible reaction for the virtual entity is to dissapear during the reaction, but granting its momentum to the real particle it has reacted with.
www.physicsforums.com /showthread.php?t=16009   (1135 words)

 JLN Labs - The TEP Project - Scalar Waves FAQ
Because of the nature of the virtual particle flux comprising it, the potential is a collection of individual virtual energies - a collection of the individual energies of a host of individually moving virtual particles.
Each particle is still almost totally separate from each other, most of the time.
A vector potential is any dynamic (nonstationary) ordering in the virtual particle flux of vacuum.
jnaudin.free.fr /html/scalwfaq.htm   (3172 words)

 A New Interpretation of Mass and Gravitational Field - Wu - Journal of Theoretics   (Site not responding. Last check: 2007-10-21)
This kind of current is formed by the directional motion of a virtual particle which is characterized by
The similarity between Gravitation Law of Universal and Coulomb’s Law indicates that it seems the mass enacts as the same character in the generation course of gravity as the charge in that of Coulombian force.
However, in this paper, we propose that the mass is a kind of current formed by the directional motion of a kind of virtual particle.
www.journaloftheoretics.com /Articles/1-5/Wu-grav-final.htm   (787 words)

 Physical Science   (Site not responding. Last check: 2007-10-21)
In Session 2, we introduced the particle model of matter by looking at examples of the behavior of matter on a macroscopic level that were best explained by assuming matter was made of particles.
In these “Virtual Particle Labs,” you will manipulate a realistic scientific model of matter as particles in order to build your understandings about how interactions and changes on a microscopic scale relate to the macroscopic scale.
The Virtual Lab: Several parameters are changed to experiment with the model.
www.learner.org /channel/courses/essential/physicalsci/session2/interactive.html   (149 words)

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