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{{Use American English|date = March 2019}}
{{Short description|Assignment of numbers to points in space}}
{{Short description|Assignment of numbers to points in space}}
{{about|associating a scalar value with every point in a space|the set whose members are [[Scalar (mathematics)|scalars]]|Field (mathematics){{!}}field}}
{{About|associating a scalar value with every point in a space|the set whose members are [[Scalar (mathematics)|scalars]]|Field (mathematics){{!}}field}}
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{{Use American English|date = March 2019}}


[[File:Scalar field.png|thumb|right|A scalar field such as temperature or pressure, where intensity of the field is represented by different hues of colors.]]
[[File:Scalar field.png|thumb|right|A scalar field such as temperature or pressure, where intensity of the field is represented by different hues of colors.]]


In [[mathematics]] and [[physics]], a '''scalar field''' or '''scalar-valued [[function (mathematics)|function]]''' associates a [[Scalar (mathematics)|scalar]] value to every point in a [[space (mathematics)|space]] – possibly [[physical space]]. The scalar may either be a ([[dimensionless]]) [[scalar (mathematics)|mathematical number]] or a [[scalar (physics)|physical quantity]]. In a physical context, scalar fields are required to be independent of the choice of reference frame, meaning that any two observers using the same units will agree on the value of the scalar field at the same absolute point in space (or [[spacetime]]) regardless of their respective points of origin. Examples used in physics include the [[temperature]] distribution throughout space, the [[pressure]] distribution in a fluid, and spin-zero quantum fields, such as the [[Higgs field]]. These fields are the subject of [[scalar field theory]].
In [[mathematics]] and [[physics]], a '''scalar field''' is a [[function (mathematics)|function]] associating a single [[number]] to each [[point (geometry)|point]] in a [[region (mathematics)|region]] of [[space (mathematics)|space]] – possibly [[physical space]]. The scalar may either be a pure [[Scalar (mathematics)|mathematical number]] ([[dimensionless]]) or a [[scalar (physics)|scalar physical quantity]] (with [[unit of measurement|units]]).
In a physical context, scalar fields are required to be independent of the choice of reference frame. That is, any two observers using the same units will agree on the value of the scalar field at the same absolute point in space (or [[spacetime]]) regardless of their respective points of origin. Examples used in physics include the [[temperature]] distribution throughout space, the [[pressure]] distribution in a fluid, and [[Spin (physics)|spin]]-zero quantum fields, such as the [[Higgs field]]. These fields are the subject of [[scalar field theory]].


==Definition==
==Definition==
Mathematically, scalar fields on a [[Region (mathematical analysis)|region]] ''U'' is a [[real-valued function|real]] or [[complex-valued function]] or [[distribution (mathematics)|distribution]] on ''U''.<ref>{{cite book |first=Tom |last=Apostol |author-link=Tom Apostol |title=Calculus
Mathematically, a scalar field on a [[Region (mathematical analysis)|region]] ''U'' is a [[real-valued function|real]] or [[complex-valued function]] or [[distribution (mathematics)|distribution]] on ''U''.<ref>{{cite book |first=Tom |last=Apostol |author-link=Tom Apostol |title=Calculus
|volume=II |publisher=Wiley |year=1969 |edition=2nd }}</ref><ref>{{springer|title=Scalar|id=s/s083240}}</ref> The region ''U'' may be a set in some [[Euclidean space]], [[Minkowski space]], or more generally a subset of a [[manifold]], and it is typical in mathematics to impose further conditions on the field, such that it be [[continuous function|continuous]] or often [[continuously differentiable]] to some order. A scalar field is a [[tensor field]] of order zero,<ref>{{springer|id=s/s083260|title=Scalar field}}</ref> and the term "scalar field" may be used to distinguish a function of this kind with a more general tensor field, [[density bundle|density]], or [[differential form]].
|volume=II |publisher=Wiley |year=1969 |edition=2nd }}</ref><ref>{{springer|title=Scalar|id=s/s083240}}</ref> The region ''U'' may be a set in some [[Euclidean space]], [[Minkowski space]], or more generally a subset of a [[manifold]], and it is typical in mathematics to impose further conditions on the field, such that it be [[continuous function|continuous]] or often [[continuously differentiable]] to some order. A scalar field is a [[tensor field]] of order zero,<ref>{{springer|id=s/s083260|title=Scalar field}}</ref> and the term "scalar field" may be used to distinguish a function of this kind with a more general tensor field, [[density bundle|density]], or [[differential form]].


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* In the [[Standard Model]] of elementary particles, a scalar [[Higgs field]] is used to give the [[lepton]]s and [[W and Z bosons|massive vector bosons]] their mass, via a combination of the [[Yukawa interaction]] and the [[spontaneous symmetry breaking]]. This mechanism is known as the [[Higgs mechanism]].<ref>{{cite journal|author=P.W. Higgs|journal=Phys. Rev. Lett.|volume=13|issue=16|pages=508–509|date=Oct 1964|title=Broken Symmetries and the Masses of Gauge Bosons|doi=10.1103/PhysRevLett.13.508|bibcode = 1964PhRvL..13..508H |doi-access=free}}</ref> A candidate for the [[Higgs boson]] was first detected at CERN in 2012.
* In the [[Standard Model]] of elementary particles, a scalar [[Higgs field]] is used to give the [[lepton]]s and [[W and Z bosons|massive vector bosons]] their mass, via a combination of the [[Yukawa interaction]] and the [[spontaneous symmetry breaking]]. This mechanism is known as the [[Higgs mechanism]].<ref>{{cite journal|author=P.W. Higgs|journal=Phys. Rev. Lett.|volume=13|issue=16|pages=508–509|date=Oct 1964|title=Broken Symmetries and the Masses of Gauge Bosons|doi=10.1103/PhysRevLett.13.508|bibcode = 1964PhRvL..13..508H |doi-access=free}}</ref> A candidate for the [[Higgs boson]] was first detected at CERN in 2012.
* In [[scalar theories of gravitation]] scalar fields are used to describe the gravitational field.
* In [[scalar theories of gravitation]] scalar fields are used to describe the gravitational field.
* [[Scalar-tensor theory|scalar-tensor theories]] represent the gravitational interaction through both a tensor and a scalar. Such attempts are for example the [[Pascual Jordan|Jordan]] theory<ref>{{cite book |first=P. |last=Jordan |title=Schwerkraft und Weltall |publisher=Vieweg |location=Braunschweig |year=1955 |url=https://books.google.com/books?id=snJTcgAACAAJ }}</ref> as a generalization of the [[Kaluza–Klein theory]] and the [[Brans–Dicke theory]].<ref>{{cite journal |first1=C. |last1=Brans |first2=R. |last2=Dicke |title=Mach's Principle and a Relativistic Theory of Gravitation |journal=Phys. Rev. |volume=124 |issue=3 |pages=925 |year=1961 |doi=10.1103/PhysRev.124.925 |bibcode=1961PhRv..124..925B }}</ref>
* [[Scalar–tensor theory|Scalar–tensor theories]] represent the gravitational interaction through both a tensor and a scalar. Such attempts are for example the [[Pascual Jordan|Jordan]] theory<ref>{{cite book |first=P. |last=Jordan |title=Schwerkraft und Weltall |publisher=Vieweg |location=Braunschweig |year=1955 |url=https://books.google.com/books?id=snJTcgAACAAJ }}</ref> as a generalization of the [[Kaluza–Klein theory]] and the [[Brans–Dicke theory]].<ref>{{cite journal |first1=C. |last1=Brans |first2=R. |last2=Dicke |title=Mach's Principle and a Relativistic Theory of Gravitation |journal=Phys. Rev. |volume=124 |issue=3 |pages=925 |year=1961 |doi=10.1103/PhysRev.124.925 |bibcode=1961PhRv..124..925B }}</ref>
:* Scalar fields like the Higgs field can be found within scalar-tensor theories, using as scalar field the Higgs field of the [[Standard Model]].<ref>{{cite journal |first=A. |last=Zee |title=Broken-Symmetric Theory of Gravity |journal=Phys. Rev. Lett. |volume=42 |issue=7 |pages=417–421 |year=1979 |doi=10.1103/PhysRevLett.42.417 |bibcode=1979PhRvL..42..417Z }}</ref><ref>{{cite journal |first1=H. |last1=Dehnen |first2=H. |last2=Frommert |first3=F. |last3=Ghaboussi |title=Higgs field and a new scalar-tensor theory of gravity |journal=Int. J. Theor. Phys. |volume=31 |issue=1 |pages=109 |year=1992 |doi=10.1007/BF00674344 |bibcode=1992IJTP...31..109D |s2cid=121308053 }}</ref> This field interacts gravitationally and [[Yukawa interaction|Yukawa]]-like (short-ranged) with the particles that get mass through it.<ref>{{cite journal |first1=H. |last1=Dehnen |first2=H. |last2=Frommmert |title=Higgs-field gravity within the standard model |journal=Int. J. Theor. Phys. |volume=30 |issue=7 |pages=985–998 [p. 987] |year=1991 |doi=10.1007/BF00673991 |bibcode=1991IJTP...30..985D |s2cid=120164928 }}</ref>
:* Scalar fields like the Higgs field can be found within scalar–tensor theories, using as scalar field the Higgs field of the [[Standard Model]].<ref>{{cite journal |first=A. |last=Zee |title=Broken-Symmetric Theory of Gravity |journal=Phys. Rev. Lett. |volume=42 |issue=7 |pages=417–421 |year=1979 |doi=10.1103/PhysRevLett.42.417 |bibcode=1979PhRvL..42..417Z }}</ref><ref>{{cite journal |first1=H. |last1=Dehnen |first2=H. |last2=Frommert |first3=F. |last3=Ghaboussi |title=Higgs field and a new scalar–tensor theory of gravity |journal=Int. J. Theor. Phys. |volume=31 |issue=1 |pages=109 |year=1992 |doi=10.1007/BF00674344 |bibcode=1992IJTP...31..109D |s2cid=121308053 }}</ref> This field interacts gravitationally and [[Yukawa interaction|Yukawa]]-like (short-ranged) with the particles that get mass through it.<ref>{{cite journal |first1=H. |last1=Dehnen |first2=H. |last2=Frommmert |title=Higgs-field gravity within the standard model |journal=Int. J. Theor. Phys. |volume=30 |issue=7 |pages=985–998 [p. 987] |year=1991 |doi=10.1007/BF00673991 |bibcode=1991IJTP...30..985D |s2cid=120164928 }}</ref>
* Scalar fields are found within superstring theories as [[dilaton]] fields, breaking the conformal symmetry of the string, though balancing the quantum anomalies of this tensor.<ref>{{cite journal |first=C. H. |last=Brans |title=The Roots of scalar-tensor theory |url=https://archive.org/details/arxiv-gr-qc0506063 |arxiv=gr-qc/0506063 |year=2005 |bibcode=2005gr.qc.....6063B }}</ref>
* Scalar fields are found within superstring theories as [[dilaton]] fields, breaking the conformal symmetry of the string, though balancing the quantum anomalies of this tensor.<ref>{{cite arXiv |first=C. H. |last=Brans |title=The Roots of scalar–tensor theory |eprint=gr-qc/0506063 |year=2005 }}</ref>
* Scalar fields are hypothesized to have caused the high accelerated expansion of the early universe ([[Inflation (cosmology)|inflation]]),<ref>{{cite journal |first=A. |last=Guth |title=Inflationary universe: A possible solution to the horizon and flatness problems |journal=Phys. Rev. D |volume=23 |pages=347–356 |year=1981 |issue=2 |doi=10.1103/PhysRevD.23.347 |bibcode=1981PhRvD..23..347G |doi-access=free }}</ref> helping to solve the [[horizon problem]] and giving a hypothetical reason for the non-vanishing [[cosmological constant]] of cosmology. Massless (i.e. long-ranged) scalar fields in this context are known as [[inflaton]]s. Massive (i.e. short-ranged) scalar fields are proposed, too, using for example Higgs-like fields.<ref>{{cite journal |first1=J. L. |last1=Cervantes-Cota |first2=H. |last2=Dehnen |title=Induced gravity inflation in the SU(5) GUT |journal=Phys. Rev. D |volume=51 |pages=395–404 |year=1995 |issue=2 |doi=10.1103/PhysRevD.51.395 |pmid=10018493 |arxiv=astro-ph/9412032 |bibcode=1995PhRvD..51..395C |s2cid=11077875 }}</ref>
* Scalar fields are hypothesized to have caused the high accelerated expansion of the early universe ([[Inflation (cosmology)|inflation]]),<ref>{{cite journal |first=A. |last=Guth |title=Inflationary universe: A possible solution to the horizon and flatness problems |journal=Phys. Rev. D |volume=23 |pages=347–356 |year=1981 |issue=2 |doi=10.1103/PhysRevD.23.347 |bibcode=1981PhRvD..23..347G |doi-access=free }}</ref> helping to solve the [[horizon problem]] and giving a hypothetical reason for the non-vanishing [[cosmological constant]] of cosmology. Massless (i.e. long-ranged) scalar fields in this context are known as [[inflaton]]s. Massive (i.e. short-ranged) scalar fields are proposed, too, using for example Higgs-like fields.<ref>{{cite journal |first1=J. L. |last1=Cervantes-Cota |first2=H. |last2=Dehnen |title=Induced gravity inflation in the SU(5) GUT |journal=Phys. Rev. D |volume=51 |pages=395–404 |year=1995 |issue=2 |doi=10.1103/PhysRevD.51.395 |pmid=10018493 |arxiv=astro-ph/9412032 |bibcode=1995PhRvD..51..395C |s2cid=11077875 }}</ref>


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==See also==
==See also==
* [[Scalar field theory]]
* [[Scalar field theory]]
* [[Vector boson]]
* [[Vector-valued function]]
* [[Vector-valued function]]


==References==
==References==
{{reflist|30em}}
{{Reflist|30em}}

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{{DEFAULTSORT:Scalar Field}}
{{DEFAULTSORT:Scalar Field}}
[[Category:Multivariable calculus]]
[[Category:Multivariable calculus]]
[[Category:Articles containing video clips]]
[[Category:Articles containing video clips]]
[[Category:Scalar physical quantities]]
[[Category:Scalar physical quantities|Field]]
[[Category:Functions and mappings]]

Latest revision as of 06:41, 17 October 2024

This article is about associating a scalar value with every point in a space. For the set whose members are scalars, see field.

A scalar field such as temperature or pressure, where intensity of the field is represented by different hues of colors.

In mathematics and physics, a scalar field is a function associating a single number to each point in a region of space – possibly physical space. The scalar may either be a pure mathematical number (dimensionless) or a scalar physical quantity (with units).

In a physical context, scalar fields are required to be independent of the choice of reference frame. That is, any two observers using the same units will agree on the value of the scalar field at the same absolute point in space (or spacetime) regardless of their respective points of origin. Examples used in physics include the temperature distribution throughout space, the pressure distribution in a fluid, and spin-zero quantum fields, such as the Higgs field. These fields are the subject of scalar field theory.

Definition

[edit]

Mathematically, a scalar field on a region U is a real or complex-valued function or distribution on U.[1][2] The region U may be a set in some Euclidean space, Minkowski space, or more generally a subset of a manifold, and it is typical in mathematics to impose further conditions on the field, such that it be continuous or often continuously differentiable to some order. A scalar field is a tensor field of order zero,[3] and the term "scalar field" may be used to distinguish a function of this kind with a more general tensor field, density, or differential form.

The scalar field of oscillating as increases. Red represents positive values, purple represents negative values, and sky blue represents values close to zero.

Physically, a scalar field is additionally distinguished by having units of measurement associated with it. In this context, a scalar field should also be independent of the coordinate system used to describe the physical system—that is, any two observers using the same units must agree on the numerical value of a scalar field at any given point of physical space. Scalar fields are contrasted with other physical quantities such as vector fields, which associate a vector to every point of a region, as well as tensor fields and spinor fields.[citation needed] More subtly, scalar fields are often contrasted with pseudoscalar fields.

Uses in physics

[edit]

In physics, scalar fields often describe the potential energy associated with a particular force. The force is a vector field, which can be obtained as a factor of the gradient of the potential energy scalar field. Examples include:

Examples in quantum theory and relativity

[edit]
  • Scalar fields like the Higgs field can be found within scalar–tensor theories, using as scalar field the Higgs field of the Standard Model.[8][9] This field interacts gravitationally and Yukawa-like (short-ranged) with the particles that get mass through it.[10]
  • Scalar fields are found within superstring theories as dilaton fields, breaking the conformal symmetry of the string, though balancing the quantum anomalies of this tensor.[11]
  • Scalar fields are hypothesized to have caused the high accelerated expansion of the early universe (inflation),[12] helping to solve the horizon problem and giving a hypothetical reason for the non-vanishing cosmological constant of cosmology. Massless (i.e. long-ranged) scalar fields in this context are known as inflatons. Massive (i.e. short-ranged) scalar fields are proposed, too, using for example Higgs-like fields.[13]

Other kinds of fields

[edit]

See also

[edit]

References

[edit]
  1. ^ Apostol, Tom (1969). Calculus. Vol. II (2nd ed.). Wiley.
  2. ^ "Scalar", Encyclopedia of Mathematics, EMS Press, 2001 [1994]
  3. ^ "Scalar field", Encyclopedia of Mathematics, EMS Press, 2001 [1994]
  4. ^ Technically, pions are actually examples of pseudoscalar mesons, which fail to be invariant under spatial inversion, but are otherwise invariant under Lorentz transformations.
  5. ^ P.W. Higgs (Oct 1964). "Broken Symmetries and the Masses of Gauge Bosons". Phys. Rev. Lett. 13 (16): 508–509. Bibcode:1964PhRvL..13..508H. doi:10.1103/PhysRevLett.13.508.
  6. ^ Jordan, P. (1955). Schwerkraft und Weltall. Braunschweig: Vieweg.
  7. ^ Brans, C.; Dicke, R. (1961). "Mach's Principle and a Relativistic Theory of Gravitation". Phys. Rev. 124 (3): 925. Bibcode:1961PhRv..124..925B. doi:10.1103/PhysRev.124.925.
  8. ^ Zee, A. (1979). "Broken-Symmetric Theory of Gravity". Phys. Rev. Lett. 42 (7): 417–421. Bibcode:1979PhRvL..42..417Z. doi:10.1103/PhysRevLett.42.417.
  9. ^ Dehnen, H.; Frommert, H.; Ghaboussi, F. (1992). "Higgs field and a new scalar–tensor theory of gravity". Int. J. Theor. Phys. 31 (1): 109. Bibcode:1992IJTP...31..109D. doi:10.1007/BF00674344. S2CID 121308053.
  10. ^ Dehnen, H.; Frommmert, H. (1991). "Higgs-field gravity within the standard model". Int. J. Theor. Phys. 30 (7): 985–998 [p. 987]. Bibcode:1991IJTP...30..985D. doi:10.1007/BF00673991. S2CID 120164928.
  11. ^ Brans, C. H. (2005). "The Roots of scalar–tensor theory". arXiv:gr-qc/0506063.
  12. ^ Guth, A. (1981). "Inflationary universe: A possible solution to the horizon and flatness problems". Phys. Rev. D. 23 (2): 347–356. Bibcode:1981PhRvD..23..347G. doi:10.1103/PhysRevD.23.347.
  13. ^ Cervantes-Cota, J. L.; Dehnen, H. (1995). "Induced gravity inflation in the SU(5) GUT". Phys. Rev. D. 51 (2): 395–404. arXiv:astro-ph/9412032. Bibcode:1995PhRvD..51..395C. doi:10.1103/PhysRevD.51.395. PMID 10018493. S2CID 11077875.
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