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The '''Sauter-Schwinger effect''', '''Schwinger effect''' or '''Schwinger pair production''' is a predicted physical phenomenon whereby matter is created by a strong electric field. It is a prediction of [[quantum electrodynamics]] (QED) in which electron-positron pairs are spontaneously created in the presence of an electric field, thereby causing the decay of the electric field. It was originally proposed by [[Fritz Sauter]] in 1931<ref>F. Sauter, "Über das Verhalten eines Elektrons im homogenen elektrischen Feld nach der relativistischen Theorie Diracs", ''Zeitschrift für Physik'', '''82''' (1931) pp. 742–764. {{doi|10.1007/BF01339461}}</ref> and further important work was carried out by [[Werner Heisenberg]] and [[Hans Heinrich Euler]] in 1936<ref>W. Heisenberg and H. Euler, "Folgerungen aus der Diracschen Theorie des Positrons", ''Zeitschrift für Physik'', '''98''' (1936) pp. 714-732. {{doi|10.1007/BF01343663}} [https://arxiv.org/abs/physics/0605038 English translation]</ref>, though it was not until 1951 when [[Julian Schwinger]] gave a complete theoretical description <ref name="Schwinger">J. Schwinger, "On Gauge Invariance and Vacuum Polarization", ''Phys. Rev.'','''82''' (1951) pp. 664–679. {{doi|10.1103/PhysRev.82.664}}</ref>.
#REDIRECT [[Schwinger limit]]

The Schwinger effect has never been observed due to the extremely strong electric-field strengths required. Pair production takes place exponentially slowly when the electric field strength is significantly below the [[Schwinger limit]], corresponding to approximately <math>\times 10^{18} \, \mathrm{V} / \mathrm{m}</math>. The rate of pair production may be significantly increased in time-dependent electric fields <ref>Brezin, E., and C. Itzykson. "Pair production in vacuum by an alternating field." ''Physical Review D'' '''2(7)''' (1970) 1191</ref><ref>Ringwald, Andreas. "Pair production from vacuum at the focus of an X-ray free electron laser." ''Physics Letters B'' '''510.1-4''' (2001): 107-116.{{doi|10.1016/S0370-2693(01)00496-8}}</ref><ref>Popov, Vladimir Stepanovich. "Schwinger mechanism of electron-positron pair production by the field of optical and X-ray lasers in vacuum." ''Journal of Experimental and Theoretical Physics Letters'' '''74.3''' (2001): 133-138.{{doi|10.1134/1.1410216}}</ref>, and as such is being pursued by high-intensity laser experiments <ref>I. C. E. Turcu et al., "High field physics and QED experiments at ELI-NP", ''Rom. Rep. Phys.'', '''68''', S145 (2016).</ref>.

==Mathematical description==
The Schwinger effect in a constant electric field takes place at a constant rate per unit volume, commonly referred to as <math>\Gamma</math>. The rate was first calculated by Schwinger<ref name="Schwinger">J. Schwinger, "On Gauge Invariance and Vacuum Polarization", ''Phys. Rev.'','''82''' (1951) pp. 664–679. {{doi|10.1103/PhysRev.82.664}}</ref> and is equal to

:<math> \Gamma = \frac{ (e E)^2 }{ 4 \pi^3} \mathrm{e}^{-\pi m^2/eE} </math>

where <math>e</math> is the (magnitude of the) charge of an electron, <math>m</math> is the mass of an electron and <math>E</math> is the electric field strength. This formula cannot be expanded in a Taylor series in <math>e^2</math>, showing the nonperturbative nature of this effect.

==See also==
*[[Julian Schwinger]]
*[[Schwinger limit]]
*[[Vacuum polarization]]

==References==
<references />

[[Category:Particle physics]]
[[Category:Hypothetical processes]]
[[Category:Quantum electrodynamics]]

Revision as of 12:56, 2 January 2019

The Sauter-Schwinger effect, Schwinger effect or Schwinger pair production is a predicted physical phenomenon whereby matter is created by a strong electric field. It is a prediction of quantum electrodynamics (QED) in which electron-positron pairs are spontaneously created in the presence of an electric field, thereby causing the decay of the electric field. It was originally proposed by Fritz Sauter in 1931[1] and further important work was carried out by Werner Heisenberg and Hans Heinrich Euler in 1936[2], though it was not until 1951 when Julian Schwinger gave a complete theoretical description [3].

The Schwinger effect has never been observed due to the extremely strong electric-field strengths required. Pair production takes place exponentially slowly when the electric field strength is significantly below the Schwinger limit, corresponding to approximately . The rate of pair production may be significantly increased in time-dependent electric fields [4][5][6], and as such is being pursued by high-intensity laser experiments [7].

Mathematical description

The Schwinger effect in a constant electric field takes place at a constant rate per unit volume, commonly referred to as . The rate was first calculated by Schwinger[3] and is equal to

where is the (magnitude of the) charge of an electron, is the mass of an electron and is the electric field strength. This formula cannot be expanded in a Taylor series in , showing the nonperturbative nature of this effect.

See also

References

  1. ^ F. Sauter, "Über das Verhalten eines Elektrons im homogenen elektrischen Feld nach der relativistischen Theorie Diracs", Zeitschrift für Physik, 82 (1931) pp. 742–764. doi:10.1007/BF01339461
  2. ^ W. Heisenberg and H. Euler, "Folgerungen aus der Diracschen Theorie des Positrons", Zeitschrift für Physik, 98 (1936) pp. 714-732. doi:10.1007/BF01343663 English translation
  3. ^ a b J. Schwinger, "On Gauge Invariance and Vacuum Polarization", Phys. Rev.,82 (1951) pp. 664–679. doi:10.1103/PhysRev.82.664
  4. ^ Brezin, E., and C. Itzykson. "Pair production in vacuum by an alternating field." Physical Review D 2(7) (1970) 1191
  5. ^ Ringwald, Andreas. "Pair production from vacuum at the focus of an X-ray free electron laser." Physics Letters B 510.1-4 (2001): 107-116.doi:10.1016/S0370-2693(01)00496-8
  6. ^ Popov, Vladimir Stepanovich. "Schwinger mechanism of electron-positron pair production by the field of optical and X-ray lasers in vacuum." Journal of Experimental and Theoretical Physics Letters 74.3 (2001): 133-138.doi:10.1134/1.1410216
  7. ^ I. C. E. Turcu et al., "High field physics and QED experiments at ELI-NP", Rom. Rep. Phys., 68, S145 (2016).