generalized geometry and double field theory a toy model

Generalized Geometry and Double Field Theory: a toy Model Patrizia - PowerPoint PPT Presentation

Generalized Geometry and Double Field Theory: a toy Model Patrizia Vitale Dipartimento di Fisica Universit` a di Napoli Federico II and INFN with V. Marotta (Heriot-Watt Edimbourgh), and F. Pezzella (INFN Napoli) Alberto Ibort Fest Classical


  1. Geometric formulation of the rigid rotator on configuration space SU (2) g βˆ’ 1 Λ™ g = i ( y 0 Λ™ y i βˆ’ y i Λ™ y 0 + Η« i jk y j Λ™ y k ) Οƒ i = i Λ™ Q i Οƒ i Since the Lagrangian reads 2 ( y 0 Λ™ y j βˆ’ y j Λ™ y 0 + Η« j kl y k Λ™ y l )( y 0 Λ™ y r βˆ’ y r Λ™ y 0 + Η« r pq y p Λ™ Q j Λ™ 2 Λ™ L 0 = 1 y q ) Ξ΄ ir = 1 Q r Ξ΄ jr Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  2. Geometric formulation of the rigid rotator on configuration space SU (2) g βˆ’ 1 Λ™ g = i ( y 0 Λ™ y i βˆ’ y i Λ™ y 0 + Η« i jk y j Λ™ y k ) Οƒ i = i Λ™ Q i Οƒ i Since the Lagrangian reads 2 ( y 0 Λ™ y j βˆ’ y j Λ™ y 0 + Η« j kl y k Λ™ y l )( y 0 Λ™ y r βˆ’ y r Λ™ y 0 + Η« r pq y p Λ™ Q j Λ™ 2 Λ™ L 0 = 1 y q ) Ξ΄ ir = 1 Q r Ξ΄ jr Tangent bundle coordinates: ( Q i , Λ™ Q i ) Q i = 0 Β¨ d g βˆ’ 1 dg οΏ½ οΏ½ Equations of motion or , = 0 dt dt Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  3. Geometric formulation of the rigid rotator Cotangent bundle T βˆ— SU (2) - Coordinates: ( Q i , I i ) Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  4. Geometric formulation of the rigid rotator Cotangent bundle T βˆ— SU (2) - Coordinates: ( Q i , I i ) with I i the conjugate momenta I j = βˆ‚ L 0 Q j = Ξ΄ jr Λ™ Q r βˆ‚ Λ™ Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  5. Geometric formulation of the rigid rotator Cotangent bundle T βˆ— SU (2) - Coordinates: ( Q i , I i ) with I i the conjugate momenta I j = βˆ‚ L 0 Q j = Ξ΄ jr Λ™ Q r βˆ‚ Λ™ Hamiltonian H 0 = 1 2 I i I j Ξ΄ ij PB’s: { y i , y j } = 0 k I k { I i , I j } = Η« ij j y 0 + Η« i { y i , I j } βˆ’ Ξ΄ i jk y k = { g , I j } = βˆ’ i Οƒ j g or g βˆ’ 1 Λ™ Λ™ EOM: I i = 0 , g = iI i Οƒ i Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  6. Geometric formulation of the rigid rotator Cotangent bundle T βˆ— SU (2) - Coordinates: ( Q i , I i ) with I i the conjugate momenta I j = βˆ‚ L 0 Q j = Ξ΄ jr Λ™ Q r βˆ‚ Λ™ Hamiltonian H 0 = 1 2 I i I j Ξ΄ ij PB’s: { y i , y j } = 0 k I k { I i , I j } = Η« ij j y 0 + Η« i { y i , I j } βˆ’ Ξ΄ i jk y k = { g , I j } = βˆ’ i Οƒ j g or g βˆ’ 1 Λ™ Λ™ EOM: I i = 0 , g = iI i Οƒ i Fiber coordinates I i are associated to the angular momentum components and the base space coordinates ( y 0 , y i ) to the orientation of the rotator. I i are constants of the motion, g undergoes a uniform precession. Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  7. The cotangent bundle T βˆ— SU (2) Remarks: As a group T βˆ— SU (2) ≃ SU (2) ⋉ R 3 with Lie algebra [ L i , L j ] = Η« k [ L i , T j ] = Η« k ij L k [ T i , T j ] = 0 ij T k Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  8. The cotangent bundle T βˆ— SU (2) Remarks: As a group T βˆ— SU (2) ≃ SU (2) ⋉ R 3 with Lie algebra [ L i , L j ] = Η« k [ L i , T j ] = Η« k ij L k [ T i , T j ] = 0 ij T k The non-trivial Poisson bracket is the Kirillov-Souriau Konstant bracket on g βˆ— Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  9. The cotangent bundle T βˆ— SU (2) Remarks: As a group T βˆ— SU (2) ≃ SU (2) ⋉ R 3 with Lie algebra [ L i , L j ] = Η« k [ L i , T j ] = Η« k ij L k [ T i , T j ] = 0 ij T k The non-trivial Poisson bracket is the Kirillov-Souriau Konstant bracket on g βˆ— In [Marmo Simoni Stern ’93] the carrier space of the dynamics has been generalized to SL (2 , C ), the Drinfeld double of SU (2). Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  10. The cotangent bundle T βˆ— SU (2) Remarks: As a group T βˆ— SU (2) ≃ SU (2) ⋉ R 3 with Lie algebra [ L i , L j ] = Η« k [ L i , T j ] = Η« k ij L k [ T i , T j ] = 0 ij T k The non-trivial Poisson bracket is the Kirillov-Souriau Konstant bracket on g βˆ— In [Marmo Simoni Stern ’93] the carrier space of the dynamics has been generalized to SL (2 , C ), the Drinfeld double of SU (2). In [Rajeev ’89 , Rajeev, Sparano P.V. ’93] the same has been done for chiral & WZW model Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  11. The cotangent bundle T βˆ— SU (2) Remarks: As a group T βˆ— SU (2) ≃ SU (2) ⋉ R 3 with Lie algebra [ L i , L j ] = Η« k [ L i , T j ] = Η« k ij L k [ T i , T j ] = 0 ij T k The non-trivial Poisson bracket is the Kirillov-Souriau Konstant bracket on g βˆ— In [Marmo Simoni Stern ’93] the carrier space of the dynamics has been generalized to SL (2 , C ), the Drinfeld double of SU (2). In [Rajeev ’89 , Rajeev, Sparano P.V. ’93] the same has been done for chiral & WZW model Here we introduce a dual dynamical model on the dual group of SU (2) and generalize to field theory. Only there, the duality transformation will be a symmetry. Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  12. The cotangent bundle T βˆ— SU (2) Remarks: As a group T βˆ— SU (2) ≃ SU (2) ⋉ R 3 with Lie algebra [ L i , L j ] = Η« k [ L i , T j ] = Η« k ij L k [ T i , T j ] = 0 ij T k The non-trivial Poisson bracket is the Kirillov-Souriau Konstant bracket on g βˆ— In [Marmo Simoni Stern ’93] the carrier space of the dynamics has been generalized to SL (2 , C ), the Drinfeld double of SU (2). In [Rajeev ’89 , Rajeev, Sparano P.V. ’93] the same has been done for chiral & WZW model Here we introduce a dual dynamical model on the dual group of SU (2) and generalize to field theory. Only there, the duality transformation will be a symmetry. Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  13. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT The algebra is spanned by e i = Οƒ i / 2 , b i = ie i [ e i , e j ] = i Η« k [ e i , b j ] = i Η« k [ b i , b j ] = βˆ’ i Η« k ij e k , ij b k , ij e k Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  14. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT The algebra is spanned by e i = Οƒ i / 2 , b i = ie i [ e i , e j ] = i Η« k [ e i , b j ] = i Η« k [ b i , b j ] = βˆ’ i Η« k ij e k , ij b k , ij e k Non-degenerate invariant scalar products: < u , v > = 2 Im ( Tr ( uv )) , βˆ€ u , v ∈ sl (2 , C ) Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  15. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT The algebra is spanned by e i = Οƒ i / 2 , b i = ie i [ e i , e j ] = i Η« k [ e i , b j ] = i Η« k [ b i , b j ] = βˆ’ i Η« k ij e k , ij b k , ij e k Non-degenerate invariant scalar products: < u , v > = 2 Im ( Tr ( uv )) , βˆ€ u , v ∈ sl (2 , C ) and ( u , v ) = 2 Re ( Tr ( uv )) , βˆ€ u , v ∈ sl (2 , C ) Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  16. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT The algebra is spanned by e i = Οƒ i / 2 , b i = ie i [ e i , e j ] = i Η« k [ e i , b j ] = i Η« k [ b i , b j ] = βˆ’ i Η« k ij e k , ij b k , ij e k Non-degenerate invariant scalar products: < u , v > = 2 Im ( Tr ( uv )) , βˆ€ u , v ∈ sl (2 , C ) and ( u , v ) = 2 Re ( Tr ( uv )) , βˆ€ u , v ∈ sl (2 , C ) w.r.t. the first one (Cartan-Killing) we have two maximal isotropic subspaces e j > = 0 , e j > = Ξ΄ j e i , ˜ < e i , e j > = < ˜ < e i , ˜ i e i = b i βˆ’ Η« ij 3 e j . with ˜ Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  17. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT The algebra is spanned by e i = Οƒ i / 2 , b i = ie i [ e i , e j ] = i Η« k [ e i , b j ] = i Η« k [ b i , b j ] = βˆ’ i Η« k ij e k , ij b k , ij e k Non-degenerate invariant scalar products: < u , v > = 2 Im ( Tr ( uv )) , βˆ€ u , v ∈ sl (2 , C ) and ( u , v ) = 2 Re ( Tr ( uv )) , βˆ€ u , v ∈ sl (2 , C ) w.r.t. the first one (Cartan-Killing) we have two maximal isotropic subspaces e j > = 0 , e j > = Ξ΄ j e i , ˜ < e i , e j > = < ˜ < e i , ˜ i e i = b i βˆ’ Η« ij 3 e j . { e i } , { ˜ e i } both subalgebras with with ˜ e k + ie k f ki [ e i , e j ] = i Η« k e i , e j ] = i Η« i e i , ˜ e j ] = if ij e k ij e k , [˜ jk ˜ j , [˜ k ˜ e i } span the Lie algebra of SB (2 , C ), the dual group of SU (2) with { ˜ f ij k = Η« ijl Η« l 3 k Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  18. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT The algebra is spanned by e i = Οƒ i / 2 , b i = ie i [ e i , e j ] = i Η« k [ e i , b j ] = i Η« k [ b i , b j ] = βˆ’ i Η« k ij e k , ij b k , ij e k Non-degenerate invariant scalar products: < u , v > = 2 Im ( Tr ( uv )) , βˆ€ u , v ∈ sl (2 , C ) and ( u , v ) = 2 Re ( Tr ( uv )) , βˆ€ u , v ∈ sl (2 , C ) w.r.t. the first one (Cartan-Killing) we have two maximal isotropic subspaces e j > = 0 , e j > = Ξ΄ j e i , ˜ < e i , e j > = < ˜ < e i , ˜ i e i = b i βˆ’ Η« ij 3 e j . { e i } , { ˜ e i } both subalgebras with with ˜ e k + ie k f ki [ e i , e j ] = i Η« k e i , e j ] = i Η« i e i , ˜ e j ] = if ij e k ij e k , [˜ jk ˜ j , [˜ k ˜ e i } span the Lie algebra of SB (2 , C ), the dual group of SU (2) with { ˜ f ij k = Η« ijl Η« l 3 k Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  19. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT ( su (2), sb (2 , C )) is a Lie bialgebra Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  20. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT ( su (2), sb (2 , C )) is a Lie bialgebra The role of su (2) and its dual algebra can be interchanged Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  21. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT ( su (2), sb (2 , C )) is a Lie bialgebra The role of su (2) and its dual algebra can be interchanged The triple ( sl (2 , C ) , su (2) , sb (2 , C )) is called a Manin triple Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  22. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT ( su (2), sb (2 , C )) is a Lie bialgebra The role of su (2) and its dual algebra can be interchanged The triple ( sl (2 , C ) , su (2) , sb (2 , C )) is called a Manin triple ⊳ g βˆ— , D is the Drinfeld double, G , G βˆ— are dual groups Given d = g ⊲ Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  23. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT ( su (2), sb (2 , C )) is a Lie bialgebra The role of su (2) and its dual algebra can be interchanged The triple ( sl (2 , C ) , su (2) , sb (2 , C )) is called a Manin triple ⊳ g βˆ— , D is the Drinfeld double, G , G βˆ— are dual groups Given d = g ⊲ For f ij D β†’ T βˆ— G k = 0 For c k ij = 0 D β†’ T βˆ— G βˆ— Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  24. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT ( su (2), sb (2 , C )) is a Lie bialgebra The role of su (2) and its dual algebra can be interchanged The triple ( sl (2 , C ) , su (2) , sb (2 , C )) is called a Manin triple ⊳ g βˆ— , D is the Drinfeld double, G , G βˆ— are dual groups Given d = g ⊲ For f ij D β†’ T βˆ— G k = 0 For c k ij = 0 D β†’ T βˆ— G βˆ— Therefore D generalizes both the cotangent bundle of SU (2) and of SB (2 , C ); Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  25. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT ( su (2), sb (2 , C )) is a Lie bialgebra The role of su (2) and its dual algebra can be interchanged The triple ( sl (2 , C ) , su (2) , sb (2 , C )) is called a Manin triple ⊳ g βˆ— , D is the Drinfeld double, G , G βˆ— are dual groups Given d = g ⊲ For f ij D β†’ T βˆ— G k = 0 For c k ij = 0 D β†’ T βˆ— G βˆ— Therefore D generalizes both the cotangent bundle of SU (2) and of SB (2 , C ); The bi-algebra structure induces Poisson structures on the double group manifold [ , ] sb (2 , C ) β†’ ( F ( SU (2)) , ˜ [ , ] su (2) β†’ ( F ( SB (2 , C )) , Ξ›); Ξ›) Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  26. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT ( su (2), sb (2 , C )) is a Lie bialgebra The role of su (2) and its dual algebra can be interchanged The triple ( sl (2 , C ) , su (2) , sb (2 , C )) is called a Manin triple ⊳ g βˆ— , D is the Drinfeld double, G , G βˆ— are dual groups Given d = g ⊲ For f ij D β†’ T βˆ— G k = 0 For c k ij = 0 D β†’ T βˆ— G βˆ— Therefore D generalizes both the cotangent bundle of SU (2) and of SB (2 , C ); The bi-algebra structure induces Poisson structures on the double group manifold [ , ] sb (2 , C ) β†’ ( F ( SU (2)) , ˜ [ , ] su (2) β†’ ( F ( SB (2 , C )) , Ξ›); Ξ›) which reduce to KSK brackets on coadjoint orbits of G , G βˆ— when f ij k = 0 , c k ij = 0 resp. Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  27. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT ( su (2), sb (2 , C )) is a Lie bialgebra The role of su (2) and its dual algebra can be interchanged The triple ( sl (2 , C ) , su (2) , sb (2 , C )) is called a Manin triple ⊳ g βˆ— , D is the Drinfeld double, G , G βˆ— are dual groups Given d = g ⊲ For f ij D β†’ T βˆ— G k = 0 For c k ij = 0 D β†’ T βˆ— G βˆ— Therefore D generalizes both the cotangent bundle of SU (2) and of SB (2 , C ); The bi-algebra structure induces Poisson structures on the double group manifold [ , ] sb (2 , C ) β†’ ( F ( SU (2)) , ˜ [ , ] su (2) β†’ ( F ( SB (2 , C )) , Ξ›); Ξ›) which reduce to KSK brackets on coadjoint orbits of G , G βˆ— when f ij k = 0 , c k ij = 0 resp. Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  28. SL (2 , C ) as a Drinfeld double Poisson brackets What are these Poisson brackets? Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  29. SL (2 , C ) as a Drinfeld double Poisson brackets What are these Poisson brackets? The double group SL (2 , C ) can be endowed with PB’s which generalize both those of T βˆ— SU (2) and of T βˆ— SB (2 C ) [[Semenov-Tyan-Shanskii ’91, Alekseev-Malkin ’94]] { Ξ³ 1 , Ξ³ 2 } = βˆ’ Ξ³ 1 Ξ³ 2 r βˆ— βˆ’ r Ξ³ 1 Ξ³ 2 whith Ξ³ 1 = Ξ³ βŠ— 1 , Ξ³ 2 = 1 βŠ— Ξ³ 2 ; Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  30. SL (2 , C ) as a Drinfeld double Poisson brackets What are these Poisson brackets? The double group SL (2 , C ) can be endowed with PB’s which generalize both those of T βˆ— SU (2) and of T βˆ— SB (2 C ) [[Semenov-Tyan-Shanskii ’91, Alekseev-Malkin ’94]] { Ξ³ 1 , Ξ³ 2 } = βˆ’ Ξ³ 1 Ξ³ 2 r βˆ— βˆ’ r Ξ³ 1 Ξ³ 2 whith Ξ³ 1 = Ξ³ βŠ— 1 , Ξ³ 2 = 1 βŠ— Ξ³ 2 ; e i βŠ— e i , r βˆ— = βˆ’ e i βŠ— ˜ e i r = ˜ is the classical Yang Baxter matrix Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  31. SL (2 , C ) as a Drinfeld double Poisson brackets What are these Poisson brackets? The double group SL (2 , C ) can be endowed with PB’s which generalize both those of T βˆ— SU (2) and of T βˆ— SB (2 C ) [[Semenov-Tyan-Shanskii ’91, Alekseev-Malkin ’94]] { Ξ³ 1 , Ξ³ 2 } = βˆ’ Ξ³ 1 Ξ³ 2 r βˆ— βˆ’ r Ξ³ 1 Ξ³ 2 whith Ξ³ 1 = Ξ³ βŠ— 1 , Ξ³ 2 = 1 βŠ— Ξ³ 2 ; e i βŠ— e i , r βˆ— = βˆ’ e i βŠ— ˜ e i r = ˜ is the classical Yang Baxter matrix The group D equipped with the Poisson bracket is also called the Heisenberg double Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  32. SL (2 , C ) as a Drinfeld double Poisson brackets What are these Poisson brackets? The double group SL (2 , C ) can be endowed with PB’s which generalize both those of T βˆ— SU (2) and of T βˆ— SB (2 C ) [[Semenov-Tyan-Shanskii ’91, Alekseev-Malkin ’94]] { Ξ³ 1 , Ξ³ 2 } = βˆ’ Ξ³ 1 Ξ³ 2 r βˆ— βˆ’ r Ξ³ 1 Ξ³ 2 whith Ξ³ 1 = Ξ³ βŠ— 1 , Ξ³ 2 = 1 βŠ— Ξ³ 2 ; e i βŠ— e i , r βˆ— = βˆ’ e i βŠ— ˜ e i r = ˜ is the classical Yang Baxter matrix The group D equipped with the Poisson bracket is also called the Heisenberg double On writing Ξ³ as Ξ³ = ˜ gg it can be shown that these brackets are compatible with { ˜ g 1 , ˜ g 2 } = βˆ’ [ r , ˜ g 1 ˜ g 2 ] , g 2 r βˆ— g 1 { ˜ g 1 , g 2 } = βˆ’ ˜ g 1 rg 2 , { g 1 , ˜ g 2 } = βˆ’ ˜ { g 1 , g 2 } = [ r βˆ— , g 1 g 2 ] , Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  33. SL (2 , C ) as a Drinfeld double Poisson brackets What are these Poisson brackets? The double group SL (2 , C ) can be endowed with PB’s which generalize both those of T βˆ— SU (2) and of T βˆ— SB (2 C ) [[Semenov-Tyan-Shanskii ’91, Alekseev-Malkin ’94]] { Ξ³ 1 , Ξ³ 2 } = βˆ’ Ξ³ 1 Ξ³ 2 r βˆ— βˆ’ r Ξ³ 1 Ξ³ 2 whith Ξ³ 1 = Ξ³ βŠ— 1 , Ξ³ 2 = 1 βŠ— Ξ³ 2 ; e i βŠ— e i , r βˆ— = βˆ’ e i βŠ— ˜ e i r = ˜ is the classical Yang Baxter matrix The group D equipped with the Poisson bracket is also called the Heisenberg double On writing Ξ³ as Ξ³ = ˜ gg it can be shown that these brackets are compatible with { ˜ g 1 , ˜ g 2 } = βˆ’ [ r , ˜ g 1 ˜ g 2 ] , g 2 r βˆ— g 1 { ˜ g 1 , g 2 } = βˆ’ ˜ g 1 rg 2 , { g 1 , ˜ g 2 } = βˆ’ ˜ { g 1 , g 2 } = [ r βˆ— , g 1 g 2 ] , Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  34. SL (2 , C ) as a Drinfeld double Poisson brackets e i βŠ— e i , In the limit Ξ» β†’ 0, with r = Ξ» ˜ Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  35. SL (2 , C ) as a Drinfeld double Poisson brackets e i βŠ— e i , ˜ g ( Ξ» ) = 1 + i Ξ» I i e i + O ( Ξ» 2 ) In the limit Ξ» β†’ 0, with r = Ξ» ˜ Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  36. SL (2 , C ) as a Drinfeld double Poisson brackets e i βŠ— e i , ˜ g ( Ξ» ) = 1 + i Ξ» I i e i + O ( Ξ» 2 ) In the limit Ξ» β†’ 0, with r = Ξ» ˜ g = y 0 Οƒ 0 + iy i Οƒ i Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  37. SL (2 , C ) as a Drinfeld double Poisson brackets e i βŠ— e i , ˜ g ( Ξ» ) = 1 + i Ξ» I i e i + O ( Ξ» 2 ) In the limit Ξ» β†’ 0, with r = Ξ» ˜ g = y 0 Οƒ 0 + iy i Οƒ i we obtain Η« k { I i , I j } = ij I k Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  38. SL (2 , C ) as a Drinfeld double Poisson brackets e i βŠ— e i , ˜ g ( Ξ» ) = 1 + i Ξ» I i e i + O ( Ξ» 2 ) In the limit Ξ» β†’ 0, with r = Ξ» ˜ g = y 0 Οƒ 0 + iy i Οƒ i we obtain Η« k { I i , I j } = ij I k { I i , y 0 } iy j Ξ΄ ij { I i , y j } = iy 0 Ξ΄ j i βˆ’ Η« j ik y k = Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  39. SL (2 , C ) as a Drinfeld double Poisson brackets e i βŠ— e i , ˜ g ( Ξ» ) = 1 + i Ξ» I i e i + O ( Ξ» 2 ) In the limit Ξ» β†’ 0, with r = Ξ» ˜ g = y 0 Οƒ 0 + iy i Οƒ i we obtain Η« k { I i , I j } = ij I k { I i , y 0 } iy j Ξ΄ ij { I i , y j } = iy 0 Ξ΄ j i βˆ’ Η« j ik y k = { y 0 , y j } { y i , y j } = 0 + O ( Ξ» ) = which reproduce correctly the canonical Poisson brackets on the cotangent bundle of SU (2). Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  40. SL (2 , C ) as a Drinfeld double Poisson brackets e i βŠ— e i , ˜ g ( Ξ» ) = 1 + i Ξ» I i e i + O ( Ξ» 2 ) In the limit Ξ» β†’ 0, with r = Ξ» ˜ g = y 0 Οƒ 0 + iy i Οƒ i we obtain Η« k { I i , I j } = ij I k { I i , y 0 } iy j Ξ΄ ij { I i , y j } = iy 0 Ξ΄ j i βˆ’ Η« j ik y k = { y 0 , y j } { y i , y j } = 0 + O ( Ξ» ) = which reproduce correctly the canonical Poisson brackets on the cotangent bundle of SU (2). Consider now r βˆ— as an independent solution of the Yang Baxter equation ρ = Β΅ e k βŠ— e k and expand g ∈ SU (2) as a function of the parameter Β΅ : g = 1 + i Β΅ ˜ Ie i + O ( Β΅ 2 ) By repeating the same analysis as above we get back the canonical Poisson structure on T βˆ— SB (2 , C ), with position coordinates and momenta now interchanged. In particular we note { ˜ I i , ˜ I j } = f ij k ˜ I k Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  41. SL (2 , C ) as a Drinfeld double Poisson brackets Last but not least, it is possible to consider a different Poisson structure on the double [Semenov] , given by 2 [ Ξ³ 1 ( r βˆ— βˆ’ r ) Ξ³ 2 βˆ’ Ξ³ 2 ( r βˆ— βˆ’ r ) Ξ³ 1 ] ; { Ξ³ 1 , Ξ³ 2 } = Ξ» Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  42. SL (2 , C ) as a Drinfeld double Poisson brackets Last but not least, it is possible to consider a different Poisson structure on the double [Semenov] , given by 2 [ Ξ³ 1 ( r βˆ— βˆ’ r ) Ξ³ 2 βˆ’ Ξ³ 2 ( r βˆ— βˆ’ r ) Ξ³ 1 ] ; { Ξ³ 1 , Ξ³ 2 } = Ξ» This is the one that correctly dualizes the bialgebra structure on d when evaluated at the identity of the group D : e i + i Ξ» ˜ I i e i and rescale r , r βˆ— by the same Expand Ξ³ ∈ D as Ξ³ = 1 + i Ξ» I i ˜ parameter Ξ» = β‡’ k I k ; { I i , I j } = Η« ij Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  43. SL (2 , C ) as a Drinfeld double Poisson brackets Last but not least, it is possible to consider a different Poisson structure on the double [Semenov] , given by 2 [ Ξ³ 1 ( r βˆ— βˆ’ r ) Ξ³ 2 βˆ’ Ξ³ 2 ( r βˆ— βˆ’ r ) Ξ³ 1 ] ; { Ξ³ 1 , Ξ³ 2 } = Ξ» This is the one that correctly dualizes the bialgebra structure on d when evaluated at the identity of the group D : e i + i Ξ» ˜ I i e i and rescale r , r βˆ— by the same Expand Ξ³ ∈ D as Ξ³ = 1 + i Ξ» I i ˜ parameter Ξ» = β‡’ k I k ; { ˜ I i , ˜ I j } = f ij k ˜ I k { I i , I j } = Η« ij Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  44. SL (2 , C ) as a Drinfeld double Poisson brackets Last but not least, it is possible to consider a different Poisson structure on the double [Semenov] , given by 2 [ Ξ³ 1 ( r βˆ— βˆ’ r ) Ξ³ 2 βˆ’ Ξ³ 2 ( r βˆ— βˆ’ r ) Ξ³ 1 ] ; { Ξ³ 1 , Ξ³ 2 } = Ξ» This is the one that correctly dualizes the bialgebra structure on d when evaluated at the identity of the group D : e i + i Ξ» ˜ I i e i and rescale r , r βˆ— by the same Expand Ξ³ ∈ D as Ξ³ = 1 + i Ξ» I i ˜ parameter Ξ» = β‡’ k I k ; { ˜ I i , ˜ I j } = f ij k ˜ I k { I i , I j } = Η« ij { I i , ˜ jk I k βˆ’ ˜ I j } I k Η« ki j = βˆ’ f i which is the Poisson bracket induced by the Lie bi-algebra structure of the double; Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  45. SL (2 , C ) as a Drinfeld double Poisson brackets Last but not least, it is possible to consider a different Poisson structure on the double [Semenov] , given by 2 [ Ξ³ 1 ( r βˆ— βˆ’ r ) Ξ³ 2 βˆ’ Ξ³ 2 ( r βˆ— βˆ’ r ) Ξ³ 1 ] ; { Ξ³ 1 , Ξ³ 2 } = Ξ» This is the one that correctly dualizes the bialgebra structure on d when evaluated at the identity of the group D : e i + i Ξ» ˜ I i e i and rescale r , r βˆ— by the same Expand Ξ³ ∈ D as Ξ³ = 1 + i Ξ» I i ˜ parameter Ξ» = β‡’ k I k ; { ˜ I i , ˜ I j } = f ij k ˜ I k { I i , I j } = Η« ij { I i , ˜ jk I k βˆ’ ˜ I j } I k Η« ki j = βˆ’ f i which is the Poisson bracket induced by the Lie bi-algebra structure of the double; I j play a symmetric role; We see that the fiber coordinates I i and ˜ Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  46. SL (2 , C ) as a Drinfeld double Poisson brackets Last but not least, it is possible to consider a different Poisson structure on the double [Semenov] , given by 2 [ Ξ³ 1 ( r βˆ— βˆ’ r ) Ξ³ 2 βˆ’ Ξ³ 2 ( r βˆ— βˆ’ r ) Ξ³ 1 ] ; { Ξ³ 1 , Ξ³ 2 } = Ξ» This is the one that correctly dualizes the bialgebra structure on d when evaluated at the identity of the group D : e i + i Ξ» ˜ I i e i and rescale r , r βˆ— by the same Expand Ξ³ ∈ D as Ξ³ = 1 + i Ξ» I i ˜ parameter Ξ» = β‡’ k I k ; { ˜ I i , ˜ I j } = f ij k ˜ I k { I i , I j } = Η« ij { I i , ˜ jk I k βˆ’ ˜ I j } I k Η« ki j = βˆ’ f i which is the Poisson bracket induced by the Lie bi-algebra structure of the double; I j play a symmetric role; We see that the fiber coordinates I i and ˜ I i appears in the expansion of g , it Moreover, since the fiber coordinate ˜ can also be thought of as the fiber coordinate of the tangent bundle TSU (2), so that the couple ( I i , ˜ I i ) identifies the fiber coordinate of the generalized bundle T βŠ• T βˆ— over SU (2). Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  47. SL (2 , C ) as a Drinfeld double Poisson brackets Last but not least, it is possible to consider a different Poisson structure on the double [Semenov] , given by 2 [ Ξ³ 1 ( r βˆ— βˆ’ r ) Ξ³ 2 βˆ’ Ξ³ 2 ( r βˆ— βˆ’ r ) Ξ³ 1 ] ; { Ξ³ 1 , Ξ³ 2 } = Ξ» This is the one that correctly dualizes the bialgebra structure on d when evaluated at the identity of the group D : e i + i Ξ» ˜ I i e i and rescale r , r βˆ— by the same Expand Ξ³ ∈ D as Ξ³ = 1 + i Ξ» I i ˜ parameter Ξ» = β‡’ k I k ; { ˜ I i , ˜ I j } = f ij k ˜ I k { I i , I j } = Η« ij { I i , ˜ jk I k βˆ’ ˜ I j } I k Η« ki j = βˆ’ f i which is the Poisson bracket induced by the Lie bi-algebra structure of the double; I j play a symmetric role; We see that the fiber coordinates I i and ˜ I i appears in the expansion of g , it Moreover, since the fiber coordinate ˜ can also be thought of as the fiber coordinate of the tangent bundle TSU (2), so that the couple ( I i , ˜ I i ) identifies the fiber coordinate of the generalized bundle T βŠ• T βˆ— over SU (2). Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  48. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT Relation to Generalized Geometry: We can consider TSU (2) βŠ• T βˆ— SU (2) ≃ T βˆ— SB (2 , C ) βŠ• T βˆ— SU (2): Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  49. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT Relation to Generalized Geometry: We can consider TSU (2) βŠ• T βˆ— SU (2) ≃ T βˆ— SB (2 , C ) βŠ• T βˆ— SU (2): Fiber coordinates are of the form P I = (˜ I i , I i ) with Poisson brackets given by the KSK brackets on the coadjoint orbits of SL (2 , C ); Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  50. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT Relation to Generalized Geometry: We can consider TSU (2) βŠ• T βˆ— SU (2) ≃ T βˆ— SB (2 , C ) βŠ• T βˆ— SU (2): Fiber coordinates are of the form P I = (˜ I i , I i ) with Poisson brackets given by the KSK brackets on the coadjoint orbits of SL (2 , C ); They are induced by the bialgebra structure of sl (2 , C ) Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  51. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT Relation to Generalized Geometry: We can consider TSU (2) βŠ• T βˆ— SU (2) ≃ T βˆ— SB (2 , C ) βŠ• T βˆ— SU (2): Fiber coordinates are of the form P I = (˜ I i , I i ) with Poisson brackets given by the KSK brackets on the coadjoint orbits of SL (2 , C ); They are induced by the bialgebra structure of sl (2 , C ) They can be identified with the C -brackets of Generalized Geometry Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  52. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT Relation to Generalized Geometry: We can consider TSU (2) βŠ• T βˆ— SU (2) ≃ T βˆ— SB (2 , C ) βŠ• T βˆ— SU (2): Fiber coordinates are of the form P I = (˜ I i , I i ) with Poisson brackets given by the KSK brackets on the coadjoint orbits of SL (2 , C ); They are induced by the bialgebra structure of sl (2 , C ) They can be identified with the C -brackets of Generalized Geometry [ C brackets are mixed brackets between vector fields and forms. They generalize Courant and Dorfmann brackets] Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  53. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT Relation to Generalized Geometry: We can consider TSU (2) βŠ• T βˆ— SU (2) ≃ T βˆ— SB (2 , C ) βŠ• T βˆ— SU (2): Fiber coordinates are of the form P I = (˜ I i , I i ) with Poisson brackets given by the KSK brackets on the coadjoint orbits of SL (2 , C ); They are induced by the bialgebra structure of sl (2 , C ) They can be identified with the C -brackets of Generalized Geometry [ C brackets are mixed brackets between vector fields and forms. They generalize Courant and Dorfmann brackets] We can also consider SL (2 , C ) as configuration space for the dynamics and TSL (2 , C ) ≃ SL (2 , C ) Γ— SL (2 , C ) as its tangent space; Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  54. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT Relation to Generalized Geometry: We can consider TSU (2) βŠ• T βˆ— SU (2) ≃ T βˆ— SB (2 , C ) βŠ• T βˆ— SU (2): Fiber coordinates are of the form P I = (˜ I i , I i ) with Poisson brackets given by the KSK brackets on the coadjoint orbits of SL (2 , C ); They are induced by the bialgebra structure of sl (2 , C ) They can be identified with the C -brackets of Generalized Geometry [ C brackets are mixed brackets between vector fields and forms. They generalize Courant and Dorfmann brackets] We can also consider SL (2 , C ) as configuration space for the dynamics and TSL (2 , C ) ≃ SL (2 , C ) Γ— SL (2 , C ) as its tangent space; In this case we have doubled configuration space coordinates = β‡’ DFT Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  55. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT Relation to Generalized Geometry: We can consider TSU (2) βŠ• T βˆ— SU (2) ≃ T βˆ— SB (2 , C ) βŠ• T βˆ— SU (2): Fiber coordinates are of the form P I = (˜ I i , I i ) with Poisson brackets given by the KSK brackets on the coadjoint orbits of SL (2 , C ); They are induced by the bialgebra structure of sl (2 , C ) They can be identified with the C -brackets of Generalized Geometry [ C brackets are mixed brackets between vector fields and forms. They generalize Courant and Dorfmann brackets] We can also consider SL (2 , C ) as configuration space for the dynamics and TSL (2 , C ) ≃ SL (2 , C ) Γ— SL (2 , C ) as its tangent space; In this case we have doubled configuration space coordinates = β‡’ DFT PB for the generalized momenta are again C -brackets Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  56. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT Relation to Generalized Geometry: We can consider TSU (2) βŠ• T βˆ— SU (2) ≃ T βˆ— SB (2 , C ) βŠ• T βˆ— SU (2): Fiber coordinates are of the form P I = (˜ I i , I i ) with Poisson brackets given by the KSK brackets on the coadjoint orbits of SL (2 , C ); They are induced by the bialgebra structure of sl (2 , C ) They can be identified with the C -brackets of Generalized Geometry [ C brackets are mixed brackets between vector fields and forms. They generalize Courant and Dorfmann brackets] We can also consider SL (2 , C ) as configuration space for the dynamics and TSL (2 , C ) ≃ SL (2 , C ) Γ— SL (2 , C ) as its tangent space; In this case we have doubled configuration space coordinates = β‡’ DFT PB for the generalized momenta are again C -brackets Notice that here C -brackets satisfy Jacobi identity because they stem from a Lie bi-algebra (the generalized tangent bundle is a Lie bi-algebroid) Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  57. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  58. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT We go back to scalar products on the Lie bi-algebra Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  59. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT We go back to scalar products on the Lie bi-algebra w.r.to the second scalar product we have another splitting ( e i , e j ) = βˆ’ ( b i , b j ) = Ξ΄ ij , ( e i , b j ) = 0 f Β± 1 with maximal isotropic subspaces: = 2 ( e i Β± b i ) √ i Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  60. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT We go back to scalar products on the Lie bi-algebra w.r.to the second scalar product we have another splitting ( e i , e j ) = βˆ’ ( b i , b j ) = Ξ΄ ij , ( e i , b j ) = 0 f Β± 1 with maximal isotropic subspaces: = 2 ( e i Β± b i ) √ i Remark : Both splittings can be related to two different complex structures on SL (2 , C ). Some connection with Gualtieri ’04 Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  61. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT We go back to scalar products on the Lie bi-algebra w.r.to the second scalar product we have another splitting ( e i , e j ) = βˆ’ ( b i , b j ) = Ξ΄ ij , ( e i , b j ) = 0 f Β± 1 with maximal isotropic subspaces: = 2 ( e i Β± b i ) √ i Remark : Both splittings can be related to two different complex structures on SL (2 , C ). Some connection with Gualtieri ’04 Introduce the doubled notation οΏ½ e i οΏ½ e i ∈ sb (2 , C ) , e I = , e i ∈ su (2) , ˜ e i ˜ Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  62. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT We go back to scalar products on the Lie bi-algebra w.r.to the second scalar product we have another splitting ( e i , e j ) = βˆ’ ( b i , b j ) = Ξ΄ ij , ( e i , b j ) = 0 f Β± 1 with maximal isotropic subspaces: = 2 ( e i Β± b i ) √ i Remark : Both splittings can be related to two different complex structures on SL (2 , C ). Some connection with Gualtieri ’04 Introduce the doubled notation οΏ½ e i οΏ½ e i ∈ sb (2 , C ) , e I = , e i ∈ su (2) , ˜ e i ˜ The first scalar product becomes Ξ΄ j οΏ½ οΏ½ 0 i < e I , e J > = L IJ = Ξ΄ i 0 j This is a O (3 , 3) invariant metric; Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  63. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT We go back to scalar products on the Lie bi-algebra w.r.to the second scalar product we have another splitting ( e i , e j ) = βˆ’ ( b i , b j ) = Ξ΄ ij , ( e i , b j ) = 0 f Β± 1 with maximal isotropic subspaces: = 2 ( e i Β± b i ) √ i Remark : Both splittings can be related to two different complex structures on SL (2 , C ). Some connection with Gualtieri ’04 Introduce the doubled notation οΏ½ e i οΏ½ e i ∈ sb (2 , C ) , e I = , e i ∈ su (2) , ˜ e i ˜ The first scalar product becomes Ξ΄ j οΏ½ οΏ½ 0 i < e I , e J > = L IJ = Ξ΄ i 0 j This is a O (3 , 3) invariant metric; ( O ( d , d ) metric is a fundamental structure in DFT) Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  64. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT The second scalar product yields οΏ½ Ξ΄ ij Η« j 3 οΏ½ i ( e I , e J ) = R IJ = Ξ΄ ij βˆ’ Η« i k 3 Η« j βˆ’ Η« i l 3 Ξ΄ kl j 3 Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  65. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT The second scalar product yields οΏ½ Ξ΄ ij Η« j 3 οΏ½ i ( e I , e J ) = R IJ = Ξ΄ ij βˆ’ Η« i k 3 Η« j βˆ’ Η« i l 3 Ξ΄ kl j 3 On denoting by C + , C βˆ’ the two subspaces spanned by { e i } , { b i } respectively, we notice that the splitting d = C + βŠ• C βˆ’ defines a positive definite metric on d via G = ( , ) C + βˆ’ ( , ) C βˆ’ Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  66. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT The second scalar product yields οΏ½ Ξ΄ ij Η« j 3 οΏ½ i ( e I , e J ) = R IJ = Ξ΄ ij βˆ’ Η« i k 3 Η« j βˆ’ Η« i l 3 Ξ΄ kl j 3 On denoting by C + , C βˆ’ the two subspaces spanned by { e i } , { b i } respectively, we notice that the splitting d = C + βŠ• C βˆ’ defines a positive definite metric on d via G = ( , ) C + βˆ’ ( , ) C βˆ’ Indicate the Riemannian metric with double round brackets: (( e i , e j )) := ( e i , e j ); (( b i , b j )) := βˆ’ ( b i , b j ); (( e i , b j )) := ( e i , b j ) = 0 which satisfies G T LG = L Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  67. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT The second scalar product yields οΏ½ Ξ΄ ij Η« j 3 οΏ½ i ( e I , e J ) = R IJ = Ξ΄ ij βˆ’ Η« i k 3 Η« j βˆ’ Η« i l 3 Ξ΄ kl j 3 On denoting by C + , C βˆ’ the two subspaces spanned by { e i } , { b i } respectively, we notice that the splitting d = C + βŠ• C βˆ’ defines a positive definite metric on d via G = ( , ) C + βˆ’ ( , ) C βˆ’ Indicate the Riemannian metric with double round brackets: (( e i , e j )) := ( e i , e j ); (( b i , b j )) := βˆ’ ( b i , b j ); (( e i , b j )) := ( e i , b j ) = 0 which satisfies G T LG = L G is a pseudo-orthogonal metric - the sum Ξ± L + Ξ² G is the generalized metric of DFT Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  68. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  69. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT Remark 1: Both scalar products have applications in theoretical physics to build invariant action functionals; two relevant examples 2+1 gravity with cosmological term as a CS theory of SL (2 , C ) [Witten ’88] Palatini action with Holst term [Holst, Barbero, Immirzi..] Remark 2: While the first product is nothing but the Cartan-Killing metric of the Lie algebra sl (2 , C ), the Riemannian structure G can be mathematically formalized in a way which clarifies its role in the context of generalized complex geometry [freidel ’17] : it can be related to the structure of para-Hermitian manifold of SL (2 , C ) and therefore generalized to even-dimensional real manifolds which are not Lie groups. Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  70. SL (2 , C ) as a Drinfeld double Relation to generalized geometry and DFT Remark 1: Both scalar products have applications in theoretical physics to build invariant action functionals; two relevant examples 2+1 gravity with cosmological term as a CS theory of SL (2 , C ) [Witten ’88] Palatini action with Holst term [Holst, Barbero, Immirzi..] Remark 2: While the first product is nothing but the Cartan-Killing metric of the Lie algebra sl (2 , C ), the Riemannian structure G can be mathematically formalized in a way which clarifies its role in the context of generalized complex geometry [freidel ’17] : it can be related to the structure of para-Hermitian manifold of SL (2 , C ) and therefore generalized to even-dimensional real manifolds which are not Lie groups. Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  71. The dual model Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  72. The dual model On T βˆ— SB (2 , C ) we may define action functional S 0 = βˆ’ 1 οΏ½ ˜ g βˆ’ 1 d ˜ g βˆ’ 1 d ˜ T r (˜ g ∧ βˆ— ˜ g ) 4 R with ˜ g : t ∈ R β†’ SB (2 , C ), T r a suitable trace over the Lie algebra Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  73. The dual model On T βˆ— SB (2 , C ) we may define action functional S 0 = βˆ’ 1 οΏ½ ˜ g βˆ’ 1 d ˜ g βˆ’ 1 d ˜ T r (˜ g ∧ βˆ— ˜ g ) 4 R with ˜ g : t ∈ R β†’ SB (2 , C ), T r a suitable trace over the Lie algebra No non-degenerate invariant products on sb (2 , C ); Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  74. The dual model On T βˆ— SB (2 , C ) we may define action functional S 0 = βˆ’ 1 οΏ½ ˜ g βˆ’ 1 d ˜ g βˆ’ 1 d ˜ T r (˜ g ∧ βˆ— ˜ g ) 4 R with ˜ g : t ∈ R β†’ SB (2 , C ), T r a suitable trace over the Lie algebra No non-degenerate invariant products on sb (2 , C ); We choose the non-degenerate one T r := (( , )) Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  75. The dual model On T βˆ— SB (2 , C ) we may define action functional S 0 = βˆ’ 1 οΏ½ ˜ g βˆ’ 1 d ˜ g βˆ’ 1 d ˜ T r (˜ g ∧ βˆ— ˜ g ) 4 R with ˜ g : t ∈ R β†’ SB (2 , C ), T r a suitable trace over the Lie algebra No non-degenerate invariant products on sb (2 , C ); We choose the non-degenerate one T r := (( , )) = β‡’ the Lagrangian Q i ( Ξ΄ ij + Η« i Λ™ l 3 ) Ξ΄ kl Λ™ L 0 = 1 ˜ ˜ k 3 Η« j ˜ Q j 2 Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  76. The dual model On T βˆ— SB (2 , C ) we may define action functional S 0 = βˆ’ 1 οΏ½ ˜ g βˆ’ 1 d ˜ g βˆ’ 1 d ˜ T r (˜ g ∧ βˆ— ˜ g ) 4 R with ˜ g : t ∈ R β†’ SB (2 , C ), T r a suitable trace over the Lie algebra No non-degenerate invariant products on sb (2 , C ); We choose the non-degenerate one T r := (( , )) = β‡’ the Lagrangian Q i ( Ξ΄ ij + Η« i Λ™ l 3 ) Ξ΄ kl Λ™ L 0 = 1 ˜ ˜ k 3 Η« j ˜ Q j 2 Q i , Λ™ g = Λ™ g βˆ’ 1 Λ™ Tangent bundle coordinates: ( ˜ ˜ ˜ e i Q i ), with ˜ ˜ Q i ˜ ( Ξ΄ ij + Η« i l 3 Ξ΄ kl ) Β¨ k 3 Η« j ˜ Equations of motion Q j = 0 Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  77. The dual model On T βˆ— SB (2 , C ) we may define action functional S 0 = βˆ’ 1 οΏ½ ˜ g βˆ’ 1 d ˜ g βˆ’ 1 d ˜ T r (˜ g ∧ βˆ— ˜ g ) 4 R with ˜ g : t ∈ R β†’ SB (2 , C ), T r a suitable trace over the Lie algebra No non-degenerate invariant products on sb (2 , C ); We choose the non-degenerate one T r := (( , )) = β‡’ the Lagrangian Q i ( Ξ΄ ij + Η« i Λ™ l 3 ) Ξ΄ kl Λ™ L 0 = 1 ˜ ˜ k 3 Η« j ˜ Q j 2 Q i , Λ™ g = Λ™ g βˆ’ 1 Λ™ Tangent bundle coordinates: ( ˜ ˜ ˜ e i Q i ), with ˜ ˜ Q i ˜ ( Ξ΄ ij + Η« i l 3 Ξ΄ kl ) Β¨ k 3 Η« j ˜ Equations of motion Q j = 0 Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  78. The dual model Cotangent bundle Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  79. The dual model Cotangent bundle T βˆ— SB (2 , C ) - Coordinates: ( ˜ Q j , ˜ I j ) Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  80. The dual model I j the Cotangent bundle T βˆ— SB (2 , C ) - Coordinates: ( ˜ Q j , ˜ I j ) with ˜ conjugate momenta I j = βˆ‚ ˜ L 0 Q r = βˆ’ i = ( Ξ΄ jr + Η« jr 3 ) Λ™ g βˆ’ 1 Λ™ ˜ ˜ e j )) 2((˜ ˜ g , ˜ βˆ‚ Λ™ ˜ Q j Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  81. The dual model I j the Cotangent bundle T βˆ— SB (2 , C ) - Coordinates: ( ˜ Q j , ˜ I j ) with ˜ conjugate momenta I j = βˆ‚ ˜ L 0 Q r = βˆ’ i = ( Ξ΄ jr + Η« jr 3 ) Λ™ g βˆ’ 1 Λ™ ˜ ˜ e j )) 2((˜ ˜ g , ˜ βˆ‚ Λ™ ˜ Q j with Λ™ ˜ 2 Η« jr 3 )˜ Q j = ( Ξ΄ jr βˆ’ 1 I r Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

  82. The dual model I j the Cotangent bundle T βˆ— SB (2 , C ) - Coordinates: ( ˜ Q j , ˜ I j ) with ˜ conjugate momenta I j = βˆ‚ ˜ L 0 Q r = βˆ’ i = ( Ξ΄ jr + Η« jr 3 ) Λ™ g βˆ’ 1 Λ™ ˜ ˜ e j )) 2((˜ ˜ g , ˜ βˆ‚ Λ™ ˜ Q j with Λ™ ˜ 2 Η« jr 3 )˜ Q j = ( Ξ΄ jr βˆ’ 1 I r Hamiltonian ˜ 2 ˜ q Ξ΄ kl )˜ H 0 = 1 I p ( Ξ΄ pq βˆ’ 1 2 Η« k 3 p Η« l 3 I q Patrizia Vitale Generalized Geometry and Double Field Theory: a toy Model

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