Quantum vacuum state
Quantum field theory |
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History |
In quantum field theory, the quantum vacuum state (also called the quantum vacuum or vacuum state) is the quantum state with the lowest possible energy. Generally, it contains no physical particles. The term zero-point field is sometimes used as a synonym for the vacuum state of a quantized field which is completely individual.[clarification needed]
According to present-day understanding of what is called the vacuum state or the quantum vacuum, it is "by no means a simple empty space".
The
The
Non-zero expectation value
If the quantum field theory can be accurately described through
Energy
The vacuum state is associated with a
Symmetry
For a
Non-linear permittivity
Quantum corrections to Maxwell's equations are expected to result in a tiny nonlinear electric polarization term in the vacuum, resulting in a field-dependent electrical permittivity ε deviating from the nominal value ε0 of vacuum permittivity.[10] These theoretical developments are described, for example, in Dittrich and Gies.[5] The theory of
Virtual particles
The presence of virtual particles can be rigorously based upon the non-commutation of the quantized electromagnetic fields. Non-commutation means that although the average values of the fields vanish in a quantum vacuum, their variances do not.[16] The term "vacuum fluctuations" refers to the variance of the field strength in the minimal energy state,[17] and is described picturesquely as evidence of "virtual particles".[18] It is sometimes attempted to provide an intuitive picture of virtual particles, or variances, based upon the Heisenberg energy-time uncertainty principle:
Physical nature of the quantum vacuum
According to
It is impossible by any procedure, no matter how idealized, to reduce any assembly to the absolute zero in a finite number of operations.[25] (See also.[26][27][28])
Photon-photon interaction can occur only through interaction with the vacuum state of some other field, for example through the Dirac electron-positron vacuum field; this is associated with the concept of vacuum polarization.[29] According to Milonni (1994): "... all quantum fields have zero-point energies and vacuum fluctuations."[30] This means that there is a component of the quantum vacuum respectively for each component field (considered in the conceptual absence of the other fields), such as the electromagnetic field, the Dirac electron-positron field, and so on. According to Milonni (1994), some of the effects attributed to the vacuum electromagnetic field can have several physical interpretations, some more conventional than others. The Casimir attraction between uncharged conductive plates is often proposed as an example of an effect of the vacuum electromagnetic field. Schwinger, DeRaad, and Milton (1978) are cited by Milonni (1994) as validly, though unconventionally, explaining the Casimir effect with a model in which "the vacuum is regarded as truly a state with all physical properties equal to zero."[31][32] In this model, the observed phenomena are explained as the effects of the electron motions on the electromagnetic field, called the source field effect. Milonni writes:
The basic idea here will be that the Casimir force may be derived from the source fields alone even in completely conventional QED, ... Milonni provides detailed argument that the measurable physical effects usually attributed to the vacuum electromagnetic field cannot be explained by that field alone, but require in addition a contribution from the self-energy of the electrons, or their radiation reaction. He writes: "The radiation reaction and the vacuum fields are two aspects of the same thing when it comes to physical interpretations of various QED processes including the Lamb shift, van der Waals forces, and Casimir effects."[33]
This point of view is also stated by Jaffe (2005): "The Casimir force can be calculated without reference to vacuum fluctuations, and like all other observable effects in QED, it vanishes as the fine structure constant, α, goes to zero."[34]
Notations
The vacuum state is written as or . The vacuum expectation value (see also Expectation value) of any field should be written as .
See also
References and notes
- ^ a b
Astrid Lambrecht (2002). Hartmut Figger; Dieter Meschede; Claus Zimmermann (eds.). Observing mechanical dissipation in the quantum vacuum: an experimental challenge; in Laser physics at the limits. Berlin/New York: Springer. p. 197. ISBN 978-3-540-42418-5.
- ^
Christopher Ray (1991). Time, space and philosophy. London/New York: Routledge. Chapter 10, p. 205. ISBN 978-0-415-03221-6.
- ^ "AIP Physics News Update,1996". Archived from the original on 2008-01-29. Retrieved 2008-02-29.
- ^ Physical Review Focus Dec. 1998
- ^ a b
Walter Dittrich & Gies H (2000). Probing the quantum vacuum: perturbative effective action approach. Berlin: Springer. ISBN 978-3-540-67428-3.
- ^
For a historical discussion, see for example Ari Ben-Menaḥem, ed. (2009). "Quantum electrodynamics (QED)". Historical Encyclopedia of Natural and Mathematical Sciences. Vol. 1 (5th ed.). Springer. pp. 4892 ff. ISBN 978-3-540-68831-0. For the Nobel prize details and the Nobel lectures by these authors, see "The Nobel Prize in Physics 1965". Nobelprize.org. Retrieved 2012-02-06.
- ISBN 978-0-521-38536-7.
- ^ Sean Carroll, Sr Research Associate - Physics, California Institute of Technology, June 22, 2006 C-SPAN broadcast of Cosmology at Yearly Kos Science Panel, Part 1
- S2CID 39308527.
- arXiv:hep-th/0610088.
- S2CID 4931745.
- ^ Mourou, G. A., T. Tajima, and S. V. Bulanov, Optics in the relativistic regime; § XI Nonlinear QED, Reviews of Modern Physics vol. 78 (no. 2), 309-371 (2006) pdf file.
- ^ Klein, James J. and B. P. Nigam, Birefringence of the vacuum, Physical Review vol. 135, p. B1279-B1280 (1964).
- S2CID 43654455.
- ].
- ISBN 978-0-471-57548-1.are also greater than or equal to this commutator.
For all field states that have classical analog the field quadrature variances
- ISBN 978-2-88124-669-2.
- ^
Milton K. Munitz (1990). Cosmic Understanding: Philosophy and Science of the Universe. Princeton University Press. p. 132. ISBN 978-0-691-02059-4.
The spontaneous, temporary emergence of particles from vacuum is called a "vacuum fluctuation".
- ^
For an example, see P. C. W. Davies (1982). The accidental universe. Cambridge University Press. pp. 106. ISBN 978-0-521-28692-3.
- ^
A vaguer description is provided by Jonathan Allday (2002). Quarks, leptons and the big bang (2nd ed.). CRC Press. pp. 224 ff. ISBN 978-0-7503-0806-9.
The interaction will last for a certain duration Δt. This implies that the amplitude for the total energy involved in the interaction is spread over a range of energies ΔE.
- ^
This "borrowing" idea has led to proposals for using the zero-point energy of vacuum as an infinite reservoir and a variety of "camps" about this interpretation. See, for example, Moray B. King (2001). Quest for zero point energy: engineering principles for 'free energy' inventions. Adventures Unlimited Press. pp. 124 ff. ISBN 978-0-932813-94-7.
- ^
Quantities satisfying a canonical commutation rule are said to be noncompatible observables, by which is meant that they can both be measured simultaneously only with limited precision. See Kiyosi Itô (1993). "§ 351 (XX.23) C: Canonical commutation relations". Encyclopedic dictionary of mathematics (2nd ed.). MIT Press. p. 1303. ISBN 978-0-262-59020-4.
- ^
ISBN 978-3-540-59358-4.
- ^ a b
For a review, see S2CID 14119708.
- Fowler, R., Guggenheim, E.A.(1965). Statistical Thermodynamics. A Version of Statistical Mechanics for Students of Physics and Chemistry, reprinted with corrections, Cambridge University Press, London, page 224.
- ^ Partington, J.R. (1949). An Advanced Treatise on Physical Chemistry, volume 1, Fundamental Principles. The Properties of Gases, Longmans, Green and Co., London, page 220.
- ^ Wilks, J. (1971). The Third Law of Thermodynamics, Chapter 6 in Thermodynamics, volume 1, ed. W. Jost, of H. Eyring, D. Henderson, W. Jost, Physical Chemistry. An Advanced Treatise, Academic Press, New York, page 477.
- ISBN 0-88318-797-3, page 342.
- ISBN 0-387-07295-0, pages 287–288.
- ISBN 0-12-498080-5, page xv.
- ISBN 0-12-498080-5, page 239.
- .
- ISBN 0-12-498080-5, page 418.
- ^ Jaffe, R.L. (2005). Casimir effect and the quantum vacuum, Phys. Rev. D 72: 021301(R), https://hadamard.com/docs/0503158v1.pdf
Further reading
- Free pdf copy of The Structured Vacuum - thinking about nothing by ISBN 3-87144-889-3.
- M.E. Peskin and D.V. Schroeder, An introduction to Quantum Field Theory.
- H. Genz, Nothingness: The Science of Empty Space
- Puthoff, H. E.; Little, S. R.; Ibison, M. (2001). "Engineering the Zero-Point Field and Polarizable Vacuum for Interstellar Flight". arXiv:astro-ph/0107316.
- E. W. Davis, V. L. Teofilo, B. Haisch, H. E. Puthoff, L. J. Nickisch, A. Rueda and D. C. Cole(2006)"Review of Experimental Concepts for Studying the Quantum Vacuum Field"