What is Virtual: Definition and 565 Discussions

In computing, a virtual machine (VM) is the virtualization/emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized hardware, software, or a combination.
Virtual machines differ and are organized by their function, shown here:

System virtual machines (also termed full virtualization VMs) provide a substitute for a real machine. They provide functionality needed to execute entire operating systems. A hypervisor uses native execution to share and manage hardware, allowing for multiple environments which are isolated from one another, yet exist on the same physical machine. Modern hypervisors use hardware-assisted virtualization, virtualization-specific hardware, primarily from the host CPUs.
Process virtual machines are designed to execute computer programs in a platform-independent environment.Some virtual machine emulators, such as QEMU and video game console emulators, are designed to also emulate (or "virtually imitate") different system architectures thus allowing execution of software applications and operating systems written for another CPU or architecture. Operating-system-level virtualization allows the resources of a computer to be partitioned via the kernel. The terms are not universally interchangeable.

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  1. D

    Uncertainty principle, virtual particle pairs and energy

    I'm a bit confused about how the uncertainty principle allows for the spontaneous creation and annihilation of virtual particle pairs. I can understand that energy conservation can be violated for a very short time as per delta_e*delta_t > h_bar/2. However, when the virtual particle pair...
  2. J

    Virtual particles colliding with other virtual particles

    Forgive that to many here this will sound like a dumb question. I have searched and searched and failed to find an answer. Give the constant creation/annihilation of all forms of particles in ZPE, it seems likely to me that some among them would collide with each other before either had a...
  3. Vorde

    Virtual Photons over Large Distances

    It's my understanding that virtual photons are 'allowed' because their existence does not violate the uncertainty principle (the form using ΔE and ΔT). If this is the case though, how is the electromagnetic force transmitted over large distances?
  4. A

    How Virtual Particles Give Rise to the electromagnetic force

    Hello, Recently I have learned that magnetism causes the Lorentz force. The electric force makes sense to me in terms of virtual photons. But how do virtual photons give rise to magnetism and the Lorentz force. Is it because when the charged particle moves through an magnetic field it comes...
  5. M

    Statics 2D Virtual Work problem regarding calculation of Normal force

    PROBLEM 1 Homework Statement The frame in the figure is supported by a hinge in A and a roller in G. It is loaded by a couple = 14 kN*m in B, a force = 12 kN in D and a distributed force = 4 kN/m on section EG. = 1.4 m. Calculate the normal force in C. Use the correct signs...
  6. J

    Optics: when are images virtual and when are they real?

    sorry, no specific homework question, although it is related to my homework in general. I don't understand what makes an image real or virtual. thanks for the help :) joe
  7. N

    Virtual Displacement: Definition & Meaning

    I have been reading Classical Mechanics by goldstein for over 2 months. I have encountered the concept of Virtual Disolacement in that book. Some of my friends have told me that it means a very small desplacement that you cannot see.. However, I am not sure if it is right. Then what is the...
  8. M

    Why virtual images in telescopes & microscopes?

    Why in telescopes and microscopes the ocular distance is such that it creates virtual images instead of real images?
  9. xaratustra

    Charged particle and virtual photons

    Imagine I am sitting on a lead ion and fly happily through the LHC tube :approve:. Suddenly I feel an strong force pushing me sideways to the left. A physicist sitting in the lab frame tells me later, that I have been going through a dipole magnet yoke with field lines from top to bottom...
  10. mrspeedybob

    Could High Energy Virtual Particles Destroy a Starship?

    I am told that the space surrounding me is filled with virtual particles, popping into and out of existence. I could believe that they exist for such short times and at such low energies that sophisticated equipment is needed to detect them. However, a collision between even 1 virtual electron...
  11. N

    Virtual particles and quantum fluctuation

    the virtual particles that are created are the result of a quantum fluctuation ..but the energy of this fluctuation must be zero so 1 particle has positive mass and the other has negative mass ...so that if they annihilate the mass is zero and they go back to not existing but if the one with...
  12. M

    Conservation of Energy and Virtual Work

    Hi, I've been reading chapter 4 in the Feynman Lectures on the conservation of energy and I've bought a book off amazon called Exercises in Introductory Physics which accompanies the series. Having looked at some of the questions I feel well out of my depth because essentially I haven't ever...
  13. E

    How would the Big Rip scenario interact with virtual particles?

    If virtual particles were prevented from annihilating fractions of a second before the Big Rip itself is actually achieved, wouldn't the universe be flooded with real particles creating an incredible amount of mass? 1) This idea is incorrect 2) The idea is correct and it temporarily delays the...
  14. F

    Virtual Particles and The Law of Conservation of Energy

    Greetings all, I'm new here. I've looked through some of the topics on virtual particles and I'm still a little confused. In Philosophy, you don't get something from nothing. In physics, there's no such thing as a free lunch. Yet many on web pages about physics a claim is being made that...
  15. S

    Virtual particle in path integral and perturbative approaches

    "Virtual particle" in path integral and perturbative approaches The term "virtual particle" is used in path integral and perturbative approaches. How do these "virtual particles" differ and how are they related? [For example, static, bound states such as the hydrogen atom are solvable by...
  16. M

    Location of a virtual image in a convexed mirror

    Homework Statement An object 2.71 * 10-2m tall is 0.14m in front of a convex mirror that has a radius of curvature 42cm. Calculate the position and height of the image, is the image inverted or upright? Homework Equations Well, I've stated that I'm using the ray model of light. As far...
  17. Vorde

    How Do Virtual Photons Create Attractive Forces Between Particles?

    How does the exchange of virtual photons result in an attractive force (for example between a proton and electron)?
  18. B

    Virtual displacements and Virtual Work

    Hi all, I am having trouble understanding Virtual displacements and related ideas and would appreciate your help! Let's say we have a simple pendulum and we take a snapshot of this system at some instant of time : A 'virtual displacement' is said to be : - consistent with the constraints on...
  19. N

    Empty spaces and virtual particles in atom

    as i know,bohr's discovery reveals that atom consist of central nucleus and electron orbit around them in empty spaces my question is-why aren't virtual particles being produced in those empty spaces?
  20. J

    Why is it possible to see a real image in a mirror?

    I am having trouble understanding how mirrors have only either a virtual image or a real image. Take a concave mirror for example. If the object is placed between the mirror and the focal point, then there is a magnified virtual image. If the object is placed between the focal point and the...
  21. A

    Delay of virtual particle pair annihilation

    My grasp of physics is limited, however, I am an engineer, thus I am asking for other's assistance in understanding how to delay the annihilation of a virtual particle pair. Most literature I've read, indicates a virtual particle pair is "real" if only briefly. QUESTION: How long is...
  22. M

    Virtual particle propagators in QFT

    I am reading a nice book (Quarks and Leptons, by Halzen and Martin) about particle physics. It states that the general form of the propagator of a virtual particle is: \dfrac{i\sum_{\text{spins}}}{p^2 - m^2} I see that this is the case for the Dirac propagator...
  23. N

    What Does the Future of Virtual Reality Hold?

    What does the future of virtual reality look like? There are a lot of hype out there for its future. What do you guys think? You may also share any articles, videos, etc..
  24. T

    AC ground,DC ground & virtual ground.

    pls explain me the concepts of ac ground,dc ground and virtual ground.?
  25. B

    Unceartianity and virtual pions.

    Hi, I'm 11 so I probably will not understand your answer if you use a lot of math without explaining it. I heard that Heisinburg's unceartianity principle was what made people believe Yukawa(spelled right?) that there are such things as virtual mesons that can be pulled out of a vaccum, you...
  26. M

    A question on Virtual Photons, and QED

    Quantum Electro Dynamics, the quantum theory of the photon, describes the photons interaction with electrons and this is what I beleived created the electromagnetic field. However recently I've heard a disscusion that virtual photons and their interaction with electrons and the polarization of...
  27. Spinnor

    Are the gluons that make up a proton considered virtual particles?

    Are the gluons that make up a proton or neutron considered virtual particles? Thanks for your help!
  28. N

    Can We Predict the Nature of Virtual Particles Created in Quantum Events?

    consider an event that takes place for a very short duration thus it have high uncertainity in energy...this energy is sufficient to create virtual particles... can we predict the nature of virtual particle that will be created(by nature i mean..it's charge,behaviour in terms of...
  29. J

    (long) question - Raman, IR spectroscopy; virtual energy states, light; heat

    I'm confused about what is going on theoretically with Raman, and light in general, wrt photon absorption, annihilation, and re-emission; I don't have the math background to understand Fourier transform, of anything past simple algebra anymore, but would like to at least have a decent...
  30. Greg Bernhardt

    A Real Virtual Currency? Emerges: Could BitCoins Threaten

    I’ve talked fairly often on this blog about the trade of virtual goods and virtual currencies in virtual worlds such as Second Life or Facebook. *While novel,*neither of*these elements are legally what they claim to be. *With respect to virtual …...
  31. L

    Dynamics (mechanics) and virtual work

    Hi everyone, I'm studying applied dynamics for college. I have a simple question and then a more importante question: F=dq/dt=ma (torque)T=dL/dt What do you call these equations, Newton-euler equations? I use these equations all the time to relate forces and torques with motion, in certain...
  32. Islam Hassan

    Higgs Field vs Fields Giving Rise to Virtual Particles

    Is the field of the theorized Higgs particle totally distinct from those fields which give rise to fleeting virtual particles? Would the latter also have some kind of 'drag' effect on elementary particles like the Higgs is thought to do? IH
  33. D

    A virtual pole vaulter in the relativistic barn

    I have sent approximately the following to a relativity prof at my university. It's summer, so I don't know if he'll read it, or be interested. So here it is for discussion. Hello, I wonder if you could tell me if the following experiment would have merit. To measure actual...
  34. B

    Debunking the Existence and Duration of Virtual Particles

    ive been reading on this forum that virtual particles flat out don't exist?then why is it said they exist for a certain amount of time?
  35. B

    What happens when a photon meets a virtual photon of the same wavelength?

    As I understand it, photons are their own anti-particle, and at all points in space there are a lot of virtual particle-antiparticle pairs being created and annhilated (perhaps infinite?), so it would seem to me that on it's journey from point A to point B that there is at least some likeliehood...
  36. D

    Virtual Particles and the DCE

    http://arxiv.org/PS_cache/arxiv/pdf/1105/1105.4714v1.pdf Does this paper shed any light on whether virtual particles are real, or not? They are speaking colloquially, as if they are real, but it sounds like there are complementary explanations that do not need to use virtual particles...
  37. P

    Virtual particles and Gauss's Law

    Does Gauss's Law apply to virtual particles? For example, when computing the field around a real proton, is the net charge in Gauss's Law the proton charge plus the contribution of all the virtual charges within the closed surface? (I'm thinking about the screening of charges by virtual...
  38. P

    Virtual particles and screening of charges

    I'm reading The Lightness of Being by Frank Wilczek. In a footnote talking about screening of a (real) positive charge by virtual particles (p47), he says "Thus the force falls off faster than 1 over the distance squared, as you'd have without screening" (by virtual particles). How then...
  39. N

    Independent virtual particle after mind experiment annihilation

    Independent virtual particle after "mind experiment" annihilation Hello good people, Probably a bit of a silly question, but I have been entertaining a bit of a thought experiment about the following. Consider the following: 1. A virtual photon is exchanged between two electrons to...
  40. M

    Virtual particles in rigorous quantum field theory

    "virtual particles" in rigorous quantum field theory If I am not mistaken "virtual particles" are just a name someone put to some integrals that we use to calculate different things, and those integrals depends on the perturbation scheme and on the gauge selected, and they don't even exist in...
  41. M

    Virtual Particles And Hidden Dimensions

    This may be way off base, but is there any support for the notion that virtual particles seem to appear and disappear because they move into and out of dimensions that we can't see? I kind of envision them appearing on arcs similar to solar prominences, where plasma follows the magnetic field...
  42. E

    Virtual particles are not matter-antimatter, is it?

    so physicists say that vacuum is filled with virtual electrons and positrons that last very shortly and then annihilate.. They are even planning on building super strong lasers to generate the EM field strong enough to separate them before annihilating - making them real. But this concerns me -...
  43. L

    Solving a Virtual Image Problem Involving a Converging Lens

    Homework Statement A converging lens of focal length 0.246 m forms a virtual image of an object. The image appears to be .933 m from the lens on the same side as the object. What is the distance between the object and the lens? Homework Equations 1/f = 1/di + 1/do Since the image is...
  44. A

    Multi Lens/Mirror problems and virtual real images

    Hey everyone, So I'm wondering whether or not a virtual object can make a real image, essentially. Let's say a real object is passed through a diverging lens, and thus creates a virtual image. This image is then bounced off a concave mirror. Now the concave mirror, if given a real object...
  45. P

    Identifying Virtual Objects: An Overview

    how is a virtual object identified ?
  46. P

    Real Image in a Concave Mirror: Virtual Object Analysis

    how can we say that the image formed by a concave mirror is always real if object is virtual? please help
  47. C

    Understanding Virtual Objects and Negative Do Values in Lenses

    I would appreciate some clarification on working with lenses and virtual objects (when the object distance do is negative). I'm not sure what happens when the do is negative and you get a positive value for di. On which side of the lens does the image go? Normally, for a lens, if di is...
  48. R

    Non-Perturbative QFT without Virtual Particles

    Hi, Is there a non-perturbative version of Quantum Field Theory that doesn't require virtual particles? If there is. Why is it not taught or emphasized so we have to completely do away with virtual particles which many pop-sci books claimed to be real when many experts here state these are...
  49. R

    Causes Virtual Particles or Vacuum Energy or Other?

    I understand the basics of the double slit experiment. I'm trying to imagine what would happen if one slit could operate at a 180 degree phase shift, or nearly that. The obvious answer is not much except between the slits, and even less if the distance between the slits is near the wave length...
  50. B

    Virtual Particles and Radioactivity

    Is it possible for a virtual particle consisting of a proton/antiproton pair to "pop" into existence close enough to the nucleus of a helium atom (two protons and two neutrons) such that the antiproton of the virtual particle annihilates one of the protons of the helium atom leaving Tritium (H3)...
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