User Tools

Site Tools


theorems:stone-von_neumann

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
Last revision Both sides next revision
theorems:stone-von_neumann [2018/05/02 09:10]
jakobadmin [Intuitive]
theorems:stone-von_neumann [2018/05/13 09:18]
jakobadmin ↷ Links adapted because of a move operation
Line 4: Line 4:
 <tabbox Intuitive> ​ <tabbox Intuitive> ​
 <​blockquote>​In typical physics quantum mechanics textbooks, one often sees calculations <​blockquote>​In typical physics quantum mechanics textbooks, one often sees calculations
-made just using the [[equations:​canonical_commutation_relations|Heisenberg commutation relations]],​ without picking a specific+made just using the [[formulas:​canonical_commutation_relations|Heisenberg commutation relations]],​ without picking a specific
 representation of the operators that satisfy these relations. This turns out representation of the operators that satisfy these relations. This turns out
 to be justified by the remarkable fact that, for the Heisenberg group, once one to be justified by the remarkable fact that, for the Heisenberg group, once one
Line 18: Line 18:
 freedom, which is the case of interest in quantum field theory, the Stone-von freedom, which is the case of interest in quantum field theory, the Stone-von
 Neumann theorem no longer holds and one has an infinity of inequivalent irreducible Neumann theorem no longer holds and one has an infinity of inequivalent irreducible
-representations,​ leading to quite different phenomena. <​cite>​https://​www.math.columbia.edu/​~woit/​QM/​qmbook.pdf</​cite></​blockquote>​+representations,​ leading to quite different phenomena. [...]It is also important to note that the Stone-von Neumann theorem is formulated 
 +for Heisenberg group representations,​ not for Heisenberg Lie algebra 
 +representations. For infinite dimensional representations in cases like this, there 
 +are representations of the Lie algebra that are “non-integrable”:​ they aren’t 
 +the derivatives of Lie group representations. For such non-integrable representations 
 +of the Heisenberg Lie algebra (i.e., operators satisfying the Heisenberg 
 +commutation relations) there are counter-examples to the analog of the Stone 
 +von-Neumann theorem. It is only for integrable representations that the theorem 
 +holds and one has a unique sort of irreducible representation.<​cite>​https://​www.math.columbia.edu/​~woit/​QM/​qmbook.pdf</​cite></​blockquote>​
 <tabbox Concrete> ​ <tabbox Concrete> ​
  
theorems/stone-von_neumann.txt · Last modified: 2018/07/18 13:24 by jakobadmin