What is Vacuum energy: Definition and 86 Discussions

Vacuum energy is an underlying background energy that exists in space throughout the entire Universe. The vacuum energy is a special case of zero-point energy that relates to the quantum vacuum.

The effects of vacuum energy can be experimentally observed in various phenomena such as spontaneous emission, the Casimir effect and the Lamb shift, and are thought to influence the behavior of the Universe on cosmological scales. Using the upper limit of the cosmological constant, the vacuum energy of free space has been estimated to be 10−9 joules (10−2 ergs), or ~5 GeV per cubic meter. However, in quantum electrodynamics, consistency with the principle of Lorentz covariance and with the magnitude of the Planck constant suggest a much larger value of 10113 joules per cubic meter. This huge discrepancy is known as the cosmological constant problem.

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  1. C

    Is it possible to turn vacuum energy into heat

    I'm doing a thermodynamics project on possible future energy sources. I've decided to try and find out if you can extract heat from vacuum energy. My initial hypothesis was that by placing to plates close together creates a magnetic attraction due to the casimir effect, which would create heat...
  2. T

    How Is Vacuum Energy Calculated for a Scalar Field?

    Hi guys! I searchead a lot for this but i couldn't find in anywhere: what calculation is made to esimate the vacuum energy of a scalar field?? I red that it starts considering the Hamiltonian in the form \hat H=\frac{1}{2}\int d^{n-1}k[\hat n_k+\frac{1}{2}\delta^{n-1}(0)]\omega and...
  3. N

    Is the cosmological constant equivalent to vacuum energy?

    Wikipedia says: second paragraph here: http://en.wikipedia.org/wiki/Dark_energy Vaccum energy (density) can vary over time and space? Is that accurate? I've read the cosmological constant can vary, but not vacuum energy.
  4. Z

    Vacuum Energy Form (aside from gamma rays)

    So apparently vacuum energy is created and destroyed within Planck time by matter, antimatter annihilation. If someone could theoretically stop or slow down time, would it be possible to tap into vacuum energy? Since annihilation creates gamma rays, I suppose vacuum energy would face the same...
  5. P

    Is vacuum energy really identical to the cosmological constant?

    When Einstein proposed the cosmological constant, it was regarded as an arbitrary constant having no connection with flat-spacetime physics (e.g. QFT to be invented later). IMHO the effective cosmological constant, in principle, should be the sum of QFT vacuum energy and Einstein's arbitrary...
  6. TrickyDicky

    Understanding Vacuum Energy Density in Relation to Universe Expansion

    Is the vacuum energy density, in case it exists which is the mainstream view, supposed to be continuously varying (decreasing) as the universe volume expands or is it really a constant (wich would be rather odd judging by what density and volume usually mean in physics)?
  7. 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...
  8. R

    Vacuum Energy and the Casmir Plate and Electromagnetics

    See followup for clarification and simplification of the question. I have a challenging question about electromagnetics, vacuum energy. I'd appreciate any leads on clearing up any of my misunderstanding. I presume if two antennas were designed to broadcast the same signal, but were designed...
  9. TrickyDicky

    Does vacuum energy gravitate and cause the universe to accelerate?

    I was wondering, since vacuum energy is supposed to have some energy density,according to standard comology equating it to dark energy and cosmological constant , does this energy gravitate? I mean it looks like according to GR its stress-energy tensor with negative pressure should generate some...
  10. J

    The Pioneer Anomaly and Vacuum Energy

    One of the proposed explanations for the Pioneer Anomaly is that the additional deceleration is caused by interaction with the vacuum energy. http://en.wikipedia.org/wiki/Pioneer_anomoly#Definition_of_inertia_modified This makes sense to me, given that some of the particles must actually...
  11. P

    Comparing Quantum Foam with Vacuum Energy and the relationship to hyperspace

    Ok I been trying to figure partially exactly what things in Quantum Mechanics, Quantum Field Theory, QED, or any physics that matter gave rise to concepts of things like hyperspace and multiverse and other theories that seem to have more of a fictional history and origin than the original...
  12. F

    Dark Matter and the vacuum energy

    I wonder if there is any correlation between the weak coupling of a quantum field in the path integral and how it adds to or cancels out vacuum energy. If so, then how would weakly interacting dark matter effect the vacuum energy? Thanks.
  13. rrw4rusty

    Vacuum Energy: same inside a rock?

    Hi, Even though it is called 'vacuum energy'... do we know or do we have some theory on... whether the activities of virtual particle pairs is the same whether in the relative vacuum of space or... with in ther Earth's atmosphere (where tests confirmed it) or... say inside a rock? Rusty
  14. R

    Potential Vacuum Energy: Does it Double Every 11B Years?

    Let's say I have a 5m3 cube of air and right next to it a 5m3 vacuum. Does the cube of air have potential energy? According to that, the potential energy would be converted into kinetic energy when the cube of air and the vacuum were joined. Would vacuum energy be the initial potential energy of...
  15. nomadreid

    Vacuum energy destruction of wormhole

    In Kip Thorne's popularization "Einstein's Outrageous Legacy", the author explains why a wormhole which has been arranged to connect two points in spacetime so that they are spatially close to one another but not the same time would find vacuum energy entering the "future" mouth, exiting out the...
  16. G

    Why is it customary to assume that the vacuum energy contribution is neglible?

    This is a question from a non-physicist. Since there is much more observed gravity then accounted for by normal matter, why do renormalization methods remove all of the vacuum's energy? I get that the infinite values make no sense, but why assume it's zero?
  17. E

    What is the Casimir Effect? Exploring Vacuum Energy.

    Can anyone explain the casimir effect to me? I've only just got back to reading parallel worlds and it's mentioned quite alot, yet i have no idea what it is. Though i think it may have something to do with vacuum energy.
  18. K

    GE - GMm/R: Does Vacuum Energy Affect Gravitational Fall?

    re: GE = minus GMm/R. It`s said that as R increases M increases to the third power and therefore falling outward is downhill but the increase in M is due to an increase in the vacuum energy which converts to a certain amount of mass. However, the mass of vacuum energy is very small. Could...
  19. B

    Vacuum Energy - Pair Production Confusion

    So, let's get this straight :smile:. Black hole evaporation is, by the layman's version, supposedly due to a negative mass particle entering the black hole, while it's counterpart leaves, as radiation. These particles are formed near the black hole by vacuum fluctuations (i.e. pair...
  20. N

    Vacuum energy in the Wess-Zumino model

    :cry:I am at my wit's end so I hope someone can help. I am trying to do what is (almost) the simplest SUSY calculation one can think of: the calculation of the vacuum energy in the Wess-Zumino model. The result shoudl be zero but I don't get that. Since SUSY is "beyond the standard...
  21. B

    Quantum friction due to vacuum energy

    Hi, I am writing an essay on quantum friction (the hypothetical force based on the casimir force). I am having trouble finding information on this concept. Wiki does not have a page on it, nor does Britanica. I have found only three Journal articles on the subject. There is more stuff about...
  22. N

    Cancellation of vacuum energy in Wess-Zumino model

    Hey, Has anyone worked out explicitly the cancellation of the vacuum energy in the Wess-Zumino model, to order g^2 (order g is trivially zero). I get a partial cancellation but there is a piece left-over. And it's not just a question of mayeb getting a sign wrong in one diagram, or a factor...
  23. K

    What is the proposed solution to the Vacuum Energy Density Crisis?

    I have done some research that has led to a possible soultion to the 120 orders-of-magnitude VED disparity betwen the VED of particle physics and the VED measured by cosmology. Nobel Prize-winner F. Wilczek calls the VED crisis a horrendous problem, indicating that there is something...
  24. B

    QM calculation of vacuum energy

    If I came up with a theory that had predictions 100 times larger or smaller than experimental observation my theory would labelled rubbish by scientists.The quantum mechanical calcualtion of vacuum energy is 120 zeros at odds with experimental observation ( casimir effect).Why aren't people...
  25. R

    Exploring Vacuum Energy Calculations

    Hey folks, Sometimes I see the calculation of the vacuum energy written as: \int\frac{d^3k}{(2\pi)^3}(k^2+m^2) and sometimes written: \int\frac{d^4k}{(2\pi)^4}log(k^2+m^2) See for example http://arxiv.org/abs/hep-ph/0105021 equation9. Does anyone know why you can increase the...
  26. A

    What is Vacuum Energy & How Does It Exist?

    Could someone please explain to me what vacuum energy is and how energy can exist in a vacuum. Sorry if this is the wrong forum, seemed as far as I know to fit best =]
  27. CJames

    Exploring the Higgs Boson: Force or Vacuum Energy?

    I have a question regarding the Higgs Boson/Field/Mechanism. My understanding of QFT is very rudimentary, but as I understand it the Higgs Boson is the quantum of the Higgs Field, which generates the vacuum energy providing the mass of the elementary particles. It assigns mass to bosons causing...
  28. D

    Vacuum Energy and Dark Energy: Are They One and the Same?

    Are these possibly one and the same, or are they completely different concepts? It seems like both are credited for the expansion of the universe, depending on who is doing the talking. dilletante
  29. D

    Does vacuum energy rely on the existence of matter?

    From what I understand, vacuum energy is a form of energy that exists in freespace, even when completely devoid of matter. So, I have two questions: 1. Can vacuum energy exist if there were no matter anywhere in the universe? 2. If so, where does this vacuum energy come from?
  30. island

    Solving Vacuum Energy Problem: e-iHT=-1, 1/2ω, Fill Negative States

    e−iHT=1→H=2πn/T=ωn ; n=0, ±1, ±2, . . . . I'd like to set the vacuum energy at 1/2ω, while requiring e-iHT=−1, and that the negative energy states be filled, as well, although, this may require further explanation. Can somebody please help me?
  31. L

    Vacuum Energy Density & Mass: 4th Power Relation

    Homework Statement Show that, in natural units h=c=1, an energy density may be expressed as the fourth power of a mass. If the vacuum energy contributed by a cosmological constant is now of order of the critical density, what is the mass to which this density corresponds? 2. The attempt...
  32. M

    What's the physical relevance of vacuum energy?

    Hi folks, There are many claims that vacuum energy has a physical relevance: in Casimir effect, in the Cosmological constant. But it seems, vacuum energy is a quantity we are not able to measure. It seems like a energy potential: the absolute value has no physical relevance, but the difference...
  33. T

    How Does Quantum Field Theory Explain Vacuum Energy and Momentum?

    I read that quantum field theory predicts that the vacuum should have some sort of energy and momentum. I could this be when the concept of energy is not absolute? All we measure in the lab is the difference in energy. In addition, I also read that the cosmological constant in Einstein...
  34. turbo

    Vacuum energy in gravitational fields

    Some time back, I asked if there was anyone doing work studying the effects of gravitational fields on virtual particle pairs. Tonight I found this paper (see section 4) - is there someone here who can steer me to similar work? http://xxx.lanl.gov/abs/astro-ph/0006423
  35. H

    Vacuum energy density and Hubble expansion

    This may be a simple question but I didn’t found anything in my references: the vacuum energy density is a constant value, which depends on the virtual excitations of the quantum fields. If the universe expands, increases its volume, and the vacuum energy density remains is constant, does this...
  36. Tyger

    The Vacuum Energy is fictitious.

    The "Vacuum Energy" is fictitious. I have bad news for the nice folks who thought that by clapping our hands together we could have free energy from the vacuum. The vacuum energy is an artifact of the way the Casimir Effect is described. Here are three websites that have good descriptions of...
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