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advanced_notions:quantum_field_theory:anomalies [2018/05/13 09:19]
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advanced_notions:quantum_field_theory:anomalies [2019/07/01 09:37] (current)
jakobadmin [Concrete]
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   * For more on this intuitive perspective of anomalies, see [[https://​arxiv.org/​abs/​1010.0943|Axial anomaly, Dirac sea, and the chiral magnetic effect]] by Dmitri E. Kharzeev   * For more on this intuitive perspective of anomalies, see [[https://​arxiv.org/​abs/​1010.0943|Axial anomaly, Dirac sea, and the chiral magnetic effect]] by Dmitri E. Kharzeev
 +
  
  
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 <tabbox Concrete> ​ <tabbox Concrete> ​
 +A classical theory possesses a symmetry if the action $S(\phi)$ is unchanged by a transformation $\phi \to \delta \phi$. In a quantum theory, however, we have a symmetry if the path integral $\int D \phi e^{iS(\phi)}$ is invariant under a given transformation $\phi \to \delta \phi$. The key observation is now that invariance of the action $S(\phi)$ does not necessarily imply invariance of the path integral since the measure $D \phi$ can be non-invariant too. In more technical terms, the reason for this is that whenever we change the integration variables, we need to remember that the Jacobian can be non-trivial. ​
 +
 +----
 +
 An anomaly is an obstruction to the construction of a quantum theory that has the same symmetry group as its action. An anomaly is an obstruction to the construction of a quantum theory that has the same symmetry group as its action.
  
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   * see also the discussion in https://​www.math.columbia.edu/​~woit/​QM/​qmbook.pdf and [[https://​physics.stackexchange.com/​questions/​33195/​classical-and-quantum-anomalies|here]]   * see also the discussion in https://​www.math.columbia.edu/​~woit/​QM/​qmbook.pdf and [[https://​physics.stackexchange.com/​questions/​33195/​classical-and-quantum-anomalies|here]]
   * and section 9.2. " Creation of particles by classical fields" ​ [[https://​arxiv.org/​pdf/​hep-th/​0510040.pdf|here]] ​   * and section 9.2. " Creation of particles by classical fields" ​ [[https://​arxiv.org/​pdf/​hep-th/​0510040.pdf|here]] ​
 +  * See also [[https://​philpapers.org/​rec/​FINGTA-2|Gauge theory, anomalies and global geometry: The interplay of physics and mathematics]] by Dana Fine & Arthur Fine
 +  * [[https://​aapt.scitation.org/​doi/​10.1119/​1.17328|Anomalies for Pedestrians]] by Holstein
 +  * See also the section "​Instantons,​ fermions, and physical consequences"​ in the book Classical Solutions in Quantum Field Theory by Erik Weinberg.
  
 <tabbox Abstract>​ <tabbox Abstract>​
 +
 +**Important Papers:**
 +
 +  * [[https://​journals.aps.org/​prd/​abstract/​10.1103/​PhysRevD.39.693|Uniqueness of quark and lepton representations in the standard model from the anomalies viewpoint]] by C. Q. Geng and R. E. Marshak
 +  * [[https://​journals.aps.org/​prd/​abstract/​10.1103/​PhysRevD.41.715|Comment on anomaly cancellation in the standard model]] by J. A. Minahan, P. Ramond, and R. C. Warner ​
 +  * [[http://​www.iaea.org/​inis/​collection/​NCLCollectionStore/​_Public/​21/​068/​21068700.pdf|CHARGED NEUTRINOS?​]] by R. Foot et. al.
 +  *[[http://​xxx.lanl.gov/​pdf/​hep-th/​0006230v1| Particle creation via relaxing hypermagnetic knots]] by C. Adam et. al.
 +
 +
 +** Recommended Resources:​**
 +
 +  * The best explanation for the idea that anomalies are related to extensions of the corresponding Lie algebra, can be found in www.atlantis-press.com/​php/​download_paper.php?​id=754. In addition, the paper nicely summarizes the various approaches that have been used so far to deal with anomalies.
 +  * An introduction to the geometric picture of anomalies can be found in [[http://​inspirehep.net/​record/​192970|Chiral Anomalies And Differential Geometry]]: Lectures Given At Les Houches, August 1983 by Bruno Zumino
 +  * See also https://​www.mathi.uni-heidelberg.de/​~walcher/​teaching/​sose16/​geo_phys/​Anomalies.pdf
 +  * see also [[https://​www.tandfonline.com/​doi/​10.1080/​00018739000101531|Geometry and topology of chiral anomalies in gauge theories]] By R. RENNIE
 +  * [[http://​inspirehep.net/​record/​213998/​files/​v15-n3-p99.pdf|Anomalies and Cocycles]] by R. Jackiw
  
  
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-**Important Papers:** 
  
-  * [[https://​journals.aps.org/​prd/​abstract/​10.1103/​PhysRevD.39.693|Uniqueness of quark and lepton representations in the standard model from the anomalies viewpoint]] by C. Q. Geng and R. E. Marshak 
-  * [[https://​journals.aps.org/​prd/​abstract/​10.1103/​PhysRevD.41.715|Comment on anomaly cancellation in the standard model]] by J. A. Minahan, P. Ramond, and R. C. Warner ​ 
-  * [[http://​www.iaea.org/​inis/​collection/​NCLCollectionStore/​_Public/​21/​068/​21068700.pdf|CHARGED NEUTRINOS?​]] by R. Foot et. al. 
-  *[[http://​xxx.lanl.gov/​pdf/​hep-th/​0006230v1| Particle creation via relaxing hypermagnetic knots]] by C. Adam et. al. 
- 
- 
-** Recommended Resources:​** 
- 
-  * The best explanation for the idea that anomalies are related to extensions of the corresponding Lie algebra, can be found in www.atlantis-press.com/​php/​download_paper.php?​id=754. In addition, the paper nicely summarizes the various approaches that have been used so far to deal with anomalies. 
-  * An introduction to the geometric picture of anomalies can be found in [[http://​inspirehep.net/​record/​192970|Chiral Anomalies And Differential Geometry]]: Lectures Given At Les Houches, August 1983 by Bruno Zumino 
-  * See also https://​www.mathi.uni-heidelberg.de/​~walcher/​teaching/​sose16/​geo_phys/​Anomalies.pdf 
-  * see also [[https://​www.tandfonline.com/​doi/​10.1080/​00018739000101531|Geometry and topology of chiral anomalies in gauge theories]] By R. RENNIE 
 <tabbox Why is it interesting?> ​ <tabbox Why is it interesting?> ​
  
advanced_notions/quantum_field_theory/anomalies.1526195963.txt.gz · Last modified: 2018/05/13 07:19 (external edit)