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advanced_notions:chern-simons [2017/11/20 13:48]
jakobadmin [Student]
advanced_notions:chern-simons [2017/11/20 14:55]
jakobadmin [Student]
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 For a great summary see section 2 in [[https://​arxiv.org/​pdf/​hep-th/​0103017.pdf|Collaborating with David Gross; Descendants of the Chiral Anomaly]] by R. Jackiw For a great summary see section 2 in [[https://​arxiv.org/​pdf/​hep-th/​0103017.pdf|Collaborating with David Gross; Descendants of the Chiral Anomaly]] by R. Jackiw
  
-<note tip>​Chern-Simons terms are known under different names in different branches of physics. In fluid mechanics it is usually called "fluid helicity",​ in plasma physics and magnetohydrodynamics "​magnetic helicity"​. In the context of field theories it is usually called Chern-Simons term.+<note tip>Chern-Simons terms describe topological properties of systems. A topological property is something that remains unchanged under small geometric changes.  
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 +Chern-Simons terms are known under different names in different branches of physics. In fluid mechanics it is usually called "fluid helicity",​ in plasma physics and magnetohydrodynamics "​magnetic helicity"​. In the context of field theories it is usually called Chern-Simons term.
 </​note>​ </​note>​
  
  
-**In Fluid Mechanics:**+-->In Fluid Mechanics#
  
 In the beginning people tried to make a mechanical model of electrodynamics. For example, Maxwell though of Faraday'​s electric and magnetic field lines as "fine tubes of variable section carrying an incompressible fluid"​. ​ In the beginning people tried to make a mechanical model of electrodynamics. For example, Maxwell though of Faraday'​s electric and magnetic field lines as "fine tubes of variable section carrying an incompressible fluid"​. ​
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 to twist is familiar to anyone seeking to to twist is familiar to anyone seeking to
 straighten out a coiled garden hose. straighten out a coiled garden hose.
-  * [[http://​www.pnas.org/​content/​111/​10/​3663.full.pdf|Helicity and singular structures in fluid dynamics]] by H. Keith Moffatt+ 
 +[[http://​www.pnas.org/​content/​111/​10/​3663.full.pdf|Helicity and singular structures in fluid dynamics]] by H. Keith Moffatt
 </​blockquote>​ </​blockquote>​
  
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 For more information on this obstruction to construct the Lagrangian for Euler'​s fluid equations, see page 9ff in https://​arxiv.org/​pdf/​hep-th/​0004084.pdf and the great review: For more information on this obstruction to construct the Lagrangian for Euler'​s fluid equations, see page 9ff in https://​arxiv.org/​pdf/​hep-th/​0004084.pdf and the great review:
  
-  * [[http://​www.annualreviews.org/​doi/​pdf/​10.1146/​annurev.fl.20.010188.001301|HAMILTONIAN FLUID MECHANICS]] by Rick Salmon ​+[[http://​www.annualreviews.org/​doi/​pdf/​10.1146/​annurev.fl.20.010188.001301|HAMILTONIAN FLUID MECHANICS]] by Rick Salmon ​
  
-**In Electrodynamics**+For an experimental proof that knotted vortices exist indeed in nature, see [[https://​www.nature.com/​articles/​nphys2560|Creation and dynamics of knotted vortices]] by Dustin Kleckner & William T. M. Irvine 
 + 
 +<-- 
 + 
 +-->In Electrodynamics#
  
 <​blockquote>​The magnetic helicity is the flux of the magnetic field through the surface bounding the volume, <​blockquote>​The magnetic helicity is the flux of the magnetic field through the surface bounding the volume,
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 the fields themselves) thereby avoiding dissipation [1]. the fields themselves) thereby avoiding dissipation [1].
 <​cite>​[[https://​arxiv.org/​pdf/​hep-th/​9911072.pdf|Creation and evolution of magnetic helicity]] by R. Jackiw et. al.</​cite></​blockquote>​ <​cite>​[[https://​arxiv.org/​pdf/​hep-th/​9911072.pdf|Creation and evolution of magnetic helicity]] by R. Jackiw et. al.</​cite></​blockquote>​
 +<--
  
-**In Non-Abelian Gauge Theories**+-->In Non-Abelian Gauge Theories#
  
 "​anomalous currents are sourced by gauge field configurations with nonzero Chern-Simons number. The "​anomalous currents are sourced by gauge field configurations with nonzero Chern-Simons number. The
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 Ref 21 is [[http://​xxx.lanl.gov/​abs/​hep-th/​9911072|Creation and evolution of magnetic helicity]] by R. Jackiw, So-Young Pi  Ref 21 is [[http://​xxx.lanl.gov/​abs/​hep-th/​9911072|Creation and evolution of magnetic helicity]] by R. Jackiw, So-Young Pi 
 +
 +<--
 <tabbox Researcher> ​ <tabbox Researcher> ​
 <​blockquote>​On a manifold it is necessary to use covariant differentiation;​ curvature measures its noncommutativitiy. Its combination as a characteristic form measures the nontriviality of the underlying bundle. This train of ideas is so simple and natural that its importance can hardly be exaggerated. <​cite>​Shiing-shen Cern</​cite></​blockquote>​ <​blockquote>​On a manifold it is necessary to use covariant differentiation;​ curvature measures its noncommutativitiy. Its combination as a characteristic form measures the nontriviality of the underlying bundle. This train of ideas is so simple and natural that its importance can hardly be exaggerated. <​cite>​Shiing-shen Cern</​cite></​blockquote>​
advanced_notions/chern-simons.txt · Last modified: 2017/11/22 10:46 by jakobadmin