Heisenberg group and Heisenberg algebra

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Pythagoras0 (토론 | 기여)님의 2020년 12월 28일 (월) 05:04 판
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introduction


relation to quantum mechanics

  • the position operators and momentum operators satisfy the relation\([X,P] = X P - P X = i \hbar\)



relation to Weyl algebra

  • a quotient of the universal enveloping algebra of the Heisenberg algebra



finite dimensional Heisenberg algebra

  • one dimensional central extension of abelian Lie algebra
  • \([p_i, q_j] = \delta_{ij}z\)
  • \([p_i, z] = 0\)
  • \([q_j, z] = 0\)
  • Gannon 180p



differential operators

  • commutation relation\(x\), \(p=\frac{d}{dx}\)\([x,p]=1\)



infinite dimensional Heisenberg algebra

  • start with a Lattice \(\langle\cdot,\cdot\rangle\)
  • make a vector space from it
  • Construct a Loop algbera\(\hat{A}=A\otimes\mathbb{C}[t,t^{-1}]\oplus\mathbb{C}c\)\(\alpha(m)=\alpha\otimes t^m\)
  • Give a bracket \([\alpha(m),\beta(n)]=m\delta_{m,-n}\langle\alpha,\beta\rangle c\)
  • add a derivation \(d\)\(d(\alpha(n))=n\alpha(n)\)\(d(c)=0\)
  • define a Lie bracket\([d,x]=d(x)\)
  • In affine Kac-Moody algebra theory, this appears as the loop algebra of Cartan subalgebra
  • commutator subalgebra
  • The automorphisms of the Heisenberg group (fixing its center) form the symplectic group



highest weight module

  • \(\hat{A}^{+}=A\otimes\mathbb{C}[t]\oplus\mathbb{C}c\)
  • \(c.v_{h}=v_{h}\)
  • for \(m>0\), \(\alpha(m)v_{h}=0\)
  • \(\alpha(0)v_{h}=hv_{h}\)


Stone-Von Neumann theorem

  • The Heisenberg group has an essentially unique irreducible unitary representation on a Hilbert space H with the center acting as a given nonzero constant (the content of the Stone-von Neumann theorem).



Heisenberg VOA



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