Flat space holography (Barnich et al, Bagchi et al, Strominger et al, ...) if holography is true ⇒ must work in flat space Just take large AdS radius limit of 10 4 AdS/CFT papers? ◮ Works straightforwardly sometimes, otherwise not ◮ Example where it works nicely: asymptotic symmetry algebra ◮ Take linear combinations of Virasoro generators L n , ¯ L n M n = 1 L n = L n − ¯ L n + ¯ � � L − n L − n ℓ ◮ Make In¨ on¨ u–Wigner contraction ℓ → ∞ on ASA [ L n , L m ] = ( n − m ) L n + m + c L 12 ( n 3 − n ) δ n + m, 0 [ L n , M m ] = ( n − m ) M n + m + c M 12 ( n 3 − n ) δ n + m, 0 [ M n , M m ] = 0 ◮ This is nothing but the BMS 3 algebra (or GCA 2 , URCA 2 , CCA 2 )! If dual field theory exists it must be a 2D Galilean CFT! Bagchi et al., Barnich et al. Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Flat space holography basics 8/25
Flat space holography (Barnich et al, Bagchi et al, Strominger et al, ...) if holography is true ⇒ must work in flat space Just take large AdS radius limit of 10 4 AdS/CFT papers? ◮ Works straightforwardly sometimes, otherwise not ◮ Example where it works nicely: asymptotic symmetry algebra ◮ Take linear combinations of Virasoro generators L n , ¯ L n M n = 1 L n = L n − ¯ L n + ¯ � � L − n L − n ℓ ◮ Make In¨ on¨ u–Wigner contraction ℓ → ∞ on ASA [ L n , L m ] = ( n − m ) L n + m + c L 12 ( n 3 − n ) δ n + m, 0 [ L n , M m ] = ( n − m ) M n + m + c M 12 ( n 3 − n ) δ n + m, 0 [ M n , M m ] = 0 ◮ This is nothing but the BMS 3 algebra (or GCA 2 , URCA 2 , CCA 2 )! ◮ Example where it does not work easily: boundary conditions Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Flat space holography basics 8/25
Flat space holography (Barnich et al, Bagchi et al, Strominger et al, ...) if holography is true ⇒ must work in flat space Just take large AdS radius limit of 10 4 AdS/CFT papers? ◮ Works straightforwardly sometimes, otherwise not ◮ Example where it works nicely: asymptotic symmetry algebra ◮ Take linear combinations of Virasoro generators L n , ¯ L n M n = 1 L n = L n − ¯ L n + ¯ � � L − n L − n ℓ ◮ Make In¨ on¨ u–Wigner contraction ℓ → ∞ on ASA [ L n , L m ] = ( n − m ) L n + m + c L 12 ( n 3 − n ) δ n + m, 0 [ L n , M m ] = ( n − m ) M n + m + c M 12 ( n 3 − n ) δ n + m, 0 [ M n , M m ] = 0 ◮ This is nothing but the BMS 3 algebra (or GCA 2 , URCA 2 , CCA 2 )! ◮ Example where it does not work easily: boundary conditions ◮ Example where it does not work: highest weight conditions Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Flat space holography basics 8/25
Flat space Einstein gravity as isl (2) Chern–Simons theory For details, references and spin-3 generalization see Gary, DG, Riegler, Rosseel ’14 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Flat space holography basics 9/25
Flat space Einstein gravity as isl (2) Chern–Simons theory For details, references and spin-3 generalization see Gary, DG, Riegler, Rosseel ’14 ◮ AdS gravity in CS formulation: sl (2) ⊕ sl (2) gauge algebra Achucarro, Townsend ’86; Witten ’88 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Flat space holography basics 9/25
Flat space Einstein gravity as isl (2) Chern–Simons theory For details, references and spin-3 generalization see Gary, DG, Riegler, Rosseel ’14 ◮ AdS gravity in CS formulation: sl (2) ⊕ sl (2) gauge algebra ◮ Flat space: isl (2) gauge algebra � CS = k �A ∧ d A + 2 S flat 3 A ∧ A ∧ A� 4 π with isl (2) connection ( a = 0 , ± 1 ) A = e a M a + ω a L a isl (2) algebra (global part of BMS/GCA) [ L a , L b ] = ( a − b ) L a + b [ L a , M b ] = ( a − b ) M a + b [ M a , M b ] = 0 Note: e a dreibein, ω a (dualized) spin-connection Bulk EOM: gauge flatness → Einstein equations F = d A + A ∧ A = 0 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Flat space holography basics 9/25
Flat space Einstein gravity as isl (2) Chern–Simons theory For details, references and spin-3 generalization see Gary, DG, Riegler, Rosseel ’14 ◮ AdS gravity in CS formulation: sl (2) ⊕ sl (2) gauge algebra ◮ Flat space: isl (2) gauge algebra � CS = k �A ∧ d A + 2 S flat 3 A ∧ A ∧ A� 4 π with isl (2) connection ( a = 0 , ± 1 ) A = e a M a + ω a L a ◮ Boundary conditions in CS formulation: � � A ( r, u, ϕ ) = b − 1 ( r ) d+ a ( u, ϕ ) + o (1) b ( r ) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Flat space holography basics 9/25
Flat space Einstein gravity as isl (2) Chern–Simons theory For details, references and spin-3 generalization see Gary, DG, Riegler, Rosseel ’14 ◮ AdS gravity in CS formulation: sl (2) ⊕ sl (2) gauge algebra ◮ Flat space: isl (2) gauge algebra � CS = k �A ∧ d A + 2 S flat 3 A ∧ A ∧ A� 4 π with isl (2) connection ( a = 0 , ± 1 ) A = e a M a + ω a L a ◮ Boundary conditions in CS formulation: � � A ( r, u, ϕ ) = b − 1 ( r ) d+ a ( u, ϕ ) + o (1) b ( r ) ◮ Flat space boundary conditions: b ( r ) = exp ( 1 2 rM − 1 ) and � � � � a ( u, ϕ ) = M 1 − M ( ϕ ) M − 1 d u + L 1 − M ( ϕ ) L − 1 − N ( u, ϕ ) M − 1 d ϕ with N ( u, ϕ ) = L ( ϕ ) + u 2 M ′ ( ϕ ) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Flat space holography basics 9/25
Flat space Einstein gravity as isl (2) Chern–Simons theory For details, references and spin-3 generalization see Gary, DG, Riegler, Rosseel ’14 ◮ AdS gravity in CS formulation: sl (2) ⊕ sl (2) gauge algebra ◮ Flat space: isl (2) gauge algebra � CS = k �A ∧ d A + 2 S flat 3 A ∧ A ∧ A� 4 π with isl (2) connection ( a = 0 , ± 1 ) A = e a M a + ω a L a ◮ Boundary conditions in CS formulation: � � A ( r, u, ϕ ) = b − 1 ( r ) d+ a ( u, ϕ ) + o (1) b ( r ) ◮ Flat space boundary conditions: b ( r ) = exp ( 1 2 rM − 1 ) and � � � � a ( u, ϕ ) = M 1 − M ( ϕ ) M − 1 d u + L 1 − M ( ϕ ) L − 1 − N ( u, ϕ ) M − 1 d ϕ with N ( u, ϕ ) = L ( ϕ ) + u 2 M ′ ( ϕ ) ◮ metric d s 2 = M d u 2 − 2 d u d r +2 N d u d ϕ + r 2 d ϕ 2 g µν ∼ 1 2 � tr �A µ A ν � → Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Flat space holography basics 9/25
Outline Motivations Flat space holography basics Recent results Generalizations & open issues Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 10/25
Correlation functions in flat space holography AdS/CFT good tool for calculating correlators What about flat space/Galilean CFT correspondence? Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 11/25
Correlation functions in flat space holography AdS/CFT good tool for calculating correlators What about flat space/Galilean CFT correspondence? ◮ What is flat space analogue of � � T ( z 1 ) T ( z 2 ) . . . T ( z 42 ) � CFT ∼ δ 42 � δg 42 Γ EH-AdS � EOM ? Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 11/25
Correlation functions in flat space holography AdS/CFT good tool for calculating correlators What about flat space/Galilean CFT correspondence? ◮ What is flat space analogue of � � T ( z 1 ) T ( z 2 ) . . . T ( z 42 ) � CFT ∼ δ 42 � δg 42 Γ EH-AdS � EOM ? ◮ Does it work? Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 11/25
Correlation functions in flat space holography AdS/CFT good tool for calculating correlators What about flat space/Galilean CFT correspondence? ◮ What is flat space analogue of � � T ( z 1 ) T ( z 2 ) . . . T ( z 42 ) � CFT ∼ δ 42 � δg 42 Γ EH-AdS � EOM ? ◮ Does it work? ◮ What is the left hand side in a Galilean CFT? Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 11/25
Correlation functions in flat space holography AdS/CFT good tool for calculating correlators What about flat space/Galilean CFT correspondence? ◮ What is flat space analogue of � � T ( z 1 ) T ( z 2 ) . . . T ( z 42 ) � CFT ∼ δ 42 � δg 42 Γ EH-AdS � EOM ? ◮ Does it work? ◮ What is the left hand side in a Galilean CFT? ◮ Shortcut to right hand side other than varying EH-action 42 times? Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 11/25
Correlation functions in flat space holography AdS/CFT good tool for calculating correlators What about flat space/Galilean CFT correspondence? ◮ What is flat space analogue of � � T ( z 1 ) T ( z 2 ) . . . T ( z 42 ) � CFT ∼ δ 42 � δg 42 Γ EH-AdS � EOM ? ◮ Does it work? ◮ What is the left hand side in a Galilean CFT? ◮ Shortcut to right hand side other than varying EH-action 42 times? Start slowly with 0-point function Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 11/25
0-point function (on-shell action) Not check of flat space holography but interesting in its own right ◮ Calculate the full on-shell action Γ Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 12/25
0-point function (on-shell action) Not check of flat space holography but interesting in its own right ◮ Calculate the full on-shell action Γ ◮ Variational principle? � � 1 d 3 x √ g R − 1 d 2 x √ γ K − I counter-term Γ = − 16 πG N 8 πG N with I counter-term chosen such that � � δ Γ EOM = 0 for all δg that preserve flat space bc’s Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 12/25
0-point function (on-shell action) Not check of flat space holography but interesting in its own right ◮ Calculate the full on-shell action Γ ◮ Variational principle? � � 1 d 3 x √ g R − 1 d 2 x √ γ K − I counter-term Γ = − 16 πG N 8 πG N with I counter-term chosen such that � � δ Γ EOM = 0 for all δg that preserve flat space bc’s Result (Detournay, DG, Sch¨ oller, Simon ’14): � � 1 d 3 x √ g R − 1 d 2 x √ γ K Γ = − 16 πG N 16 πG N � �� � 1 2 GHY! follows also as limit from AdS using Mora, Olea, Troncoso, Zanelli ’04 independently confirmed by Barnich, Gonzalez, Maloney, Oblak ’15 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 12/25
0-point function (on-shell action) Not check of flat space holography but interesting in its own right ◮ Calculate the full on-shell action Γ ◮ Variational principle? ◮ Phase transitions? Standard procedure (Gibbons, Hawking ’77; Hawking, Page ’83) Evaluate Euclidean partition function in semi-classical limit � � D g e − Γ[ g ] = e − Γ[ g c ( T, Ω)] × Z fluct. Z ( T, Ω) = g c path integral bc’s specified by temperature T and angular velocity Ω Two Euclidean saddle points in same ensemble if ◮ same temperature T = 1 /β and angular velocity Ω ◮ obey flat space boundary conditions ◮ solutions without conical singularities Periodicities fixed: ( τ E , ϕ ) ∼ ( τ E + β, ϕ + β Ω) ∼ ( τ E , ϕ + 2 π ) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 12/25
0-point function (on-shell action) Not check of flat space holography but interesting in its own right ◮ Calculate the full on-shell action Γ ◮ Variational principle? ◮ Phase transitions? 3D Euclidean Einstein gravity: for each T , Ω two saddle points: ◮ Hot flat space d s 2 = d τ 2 E + d r 2 + r 2 d ϕ 2 ◮ Flat space cosmology r 2 d r 2 � � 0 ) + r 2 � � 2 1 − r 2 d ϕ − r + r 0 d s 2 = r 2 0 d τ 2 E + d τ E + ( r 2 − r 2 + r 2 r 2 r 2 shifted-boost orbifold, see Cornalba, Costa ’02 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 12/25
0-point function (on-shell action) Not check of flat space holography but interesting in its own right ◮ Calculate the full on-shell action Γ ◮ Variational principle? ◮ Phase transitions? ◮ Plug two Euclidean saddles in on-shell action and compare free energies 1 F FSC = − r + F HFS = − 8 G N 8 G N Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 12/25
0-point function (on-shell action) Not check of flat space holography but interesting in its own right ◮ Calculate the full on-shell action Γ ◮ Variational principle? ◮ Phase transitions? ◮ Plug two Euclidean saddles in on-shell action and compare free energies 1 F FSC = − r + F HFS = − 8 G N 8 G N ◮ Result of this comparison ◮ r + > 1 : FSC dominant saddle ◮ r + < 1 : HFS dominant saddle Critical temperature: 1 = Ω T c = 2 πr 0 2 π HFS “melts” into FSC at T > T c Bagchi, Detournay, DG, Simon ’13 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 12/25
1-point functions (conserved charges) First check of entries in holographic dictionary: identification of sources and vevs In AdS 3 : � � � T µν � δ Γ EOM ∼ vev × δ source ∼ BY × δg NN µν ∂ M ∂ M Note that T µν BY follows from canonical analysis as well (conserved charges) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 13/25
1-point functions (conserved charges) First check of entries in holographic dictionary: identification of sources and vevs In AdS 3 : � � � T µν � δ Γ EOM ∼ vev × δ source ∼ BY × δg NN µν ∂ M ∂ M Note that T µν BY follows from canonical analysis as well (conserved charges) In flat space: ◮ non-normalizable solutions to linearized EOM? ◮ analogue of Brown–York stress tensor? ◮ comparison with canonical results Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 13/25
1-point functions (conserved charges) First check of entries in holographic dictionary: identification of sources and vevs In AdS 3 : � � � T µν � δ Γ EOM ∼ vev × δ source ∼ BY × δg NN µν ∂ M ∂ M Note that T µν BY follows from canonical analysis as well (conserved charges) In flat space: ◮ non-normalizable solutions to linearized EOM? ◮ analogue of Brown–York stress tensor? ◮ comparison with canonical results everything works (Detournay, DG, Sch¨ oller, Simon, ’14) mass and angular momentum: M = g tt N = g tϕ 8 G 4 G full tower of canonical charges: see Barnich, Compere ’06 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 13/25
2-point functions (anomalous terms) First check sensitive to central charges in symmetry algebra Galilean CFT on cylinder ( ϕ ∼ ϕ + 2 π ): � M ( u 1 , ϕ 1 ) M ( u 2 , ϕ 2 ) � = 0 � M ( u 1 , ϕ 1 ) N ( u 2 , ϕ 2 ) � = c M 2 s 4 12 � N ( u 1 , ϕ 1 ) N ( u 2 , ϕ 2 ) � = c L − 2 c M τ 12 2 s 4 12 with s ij = 2 sin[( ϕ i − ϕ j ) / 2] , τ ij = ( u i − u j ) cot[( ϕ i − ϕ j ) / 2] Fourier modes of Galilean CFT stress tensor on cylinder: � M n e − inϕ − c M M := 24 n � � � e − inϕ − c L N := L n − inuM n 24 n Conservation equations: ∂ u M = 0 , ∂ u N = ∂ ϕ M Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 14/25
2-point functions (anomalous terms) First check sensitive to central charges in symmetry algebra Galilean CFT on cylinder ( ϕ ∼ ϕ + 2 π ): � M ( u 1 , ϕ 1 ) M ( u 2 , ϕ 2 ) � = 0 � M ( u 1 , ϕ 1 ) N ( u 2 , ϕ 2 ) � = c M 2 s 4 12 � N ( u 1 , ϕ 1 ) N ( u 2 , ϕ 2 ) � = c L − 2 c M τ 12 2 s 4 12 with s ij = 2 sin[( ϕ i − ϕ j ) / 2] , τ ij = ( u i − u j ) cot[( ϕ i − ϕ j ) / 2] Short-cut on gravity side: ◮ Do not calculate second variation of action Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 14/25
2-point functions (anomalous terms) First check sensitive to central charges in symmetry algebra Galilean CFT on cylinder ( ϕ ∼ ϕ + 2 π ): � M ( u 1 , ϕ 1 ) M ( u 2 , ϕ 2 ) � = 0 � M ( u 1 , ϕ 1 ) N ( u 2 , ϕ 2 ) � = c M 2 s 4 12 � N ( u 1 , ϕ 1 ) N ( u 2 , ϕ 2 ) � = c L − 2 c M τ 12 2 s 4 12 with s ij = 2 sin[( ϕ i − ϕ j ) / 2] , τ ij = ( u i − u j ) cot[( ϕ i − ϕ j ) / 2] Short-cut on gravity side: ◮ Do not calculate second variation of action ◮ Calculate first variation of action on non-trivial background Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 14/25
2-point functions (anomalous terms) First check sensitive to central charges in symmetry algebra Galilean CFT on cylinder ( ϕ ∼ ϕ + 2 π ): � M ( u 1 , ϕ 1 ) M ( u 2 , ϕ 2 ) � = 0 � M ( u 1 , ϕ 1 ) N ( u 2 , ϕ 2 ) � = c M 2 s 4 12 � N ( u 1 , ϕ 1 ) N ( u 2 , ϕ 2 ) � = c L − 2 c M τ 12 2 s 4 12 with s ij = 2 sin[( ϕ i − ϕ j ) / 2] , τ ij = ( u i − u j ) cot[( ϕ i − ϕ j ) / 2] Short-cut on gravity side: ◮ Do not calculate second variation of action ◮ Calculate first variation of action on non-trivial background ◮ Can iterate this procedure to higher n -point functions Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 14/25
2-point functions (anomalous terms) First check sensitive to central charges in symmetry algebra Galilean CFT on cylinder ( ϕ ∼ ϕ + 2 π ): � M ( u 1 , ϕ 1 ) M ( u 2 , ϕ 2 ) � = 0 � M ( u 1 , ϕ 1 ) N ( u 2 , ϕ 2 ) � = c M 2 s 4 12 � N ( u 1 , ϕ 1 ) N ( u 2 , ϕ 2 ) � = c L − 2 c M τ 12 2 s 4 12 with s ij = 2 sin[( ϕ i − ϕ j ) / 2] , τ ij = ( u i − u j ) cot[( ϕ i − ϕ j ) / 2] Short-cut on gravity side: ◮ Do not calculate second variation of action ◮ Calculate first variation of action on non-trivial background ◮ Can iterate this procedure to higher n -point functions Summarize first how this works in the AdS case Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 14/25
2-point functions (anomalous terms) Illustrate shortcut in AdS 3 /CFT 2 (restrict to one holomorphic sector) ◮ On CFT side deform free action S 0 by source term µ for stress tensor � d 2 z µ ( z, ¯ S µ = S 0 + z ) T ( z ) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 15/25
2-point functions (anomalous terms) Illustrate shortcut in AdS 3 /CFT 2 (restrict to one holomorphic sector) ◮ On CFT side deform free action S 0 by source term µ for stress tensor � d 2 z µ ( z, ¯ S µ = S 0 + z ) T ( z ) ◮ Localize source z ) = ǫ δ (2) ( z − z 2 , ¯ µ ( z, ¯ z − ¯ z 2 ) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 15/25
2-point functions (anomalous terms) Illustrate shortcut in AdS 3 /CFT 2 (restrict to one holomorphic sector) ◮ On CFT side deform free action S 0 by source term µ for stress tensor � d 2 z µ ( z, ¯ S µ = S 0 + z ) T ( z ) ◮ Localize source z ) = ǫ δ (2) ( z − z 2 , ¯ µ ( z, ¯ z − ¯ z 2 ) ◮ 1-point function in µ -vacuum → 2-point function in 0-vacuum � T 1 � µ = � T 1 � 0 + ǫ � T 1 T 2 � 0 + O ( ǫ 2 ) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 15/25
2-point functions (anomalous terms) Illustrate shortcut in AdS 3 /CFT 2 (restrict to one holomorphic sector) ◮ On CFT side deform free action S 0 by source term µ for stress tensor � d 2 z µ ( z, ¯ S µ = S 0 + z ) T ( z ) ◮ Localize source z ) = ǫ δ (2) ( z − z 2 , ¯ µ ( z, ¯ z − ¯ z 2 ) ◮ 1-point function in µ -vacuum → 2-point function in 0-vacuum � T 1 � µ = � T 1 � 0 + ǫ � T 1 T 2 � 0 + O ( ǫ 2 ) ◮ On gravity side exploit sl (2) CS formulation with chemical potentials A = b − 1 (d+ a ) b b = e ρL 0 a z = L + − L k L − a ¯ z = µL + + . . . Drinfeld, Sokolov ’84, Polyakov ’87, H. Verlinde ’90 Ba˜ nados, Caro ’04 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 15/25
2-point functions (anomalous terms) Illustrate shortcut in AdS 3 /CFT 2 (restrict to one holomorphic sector) ◮ On CFT side deform free action S 0 by source term µ for stress tensor � d 2 z µ ( z, ¯ S µ = S 0 + z ) T ( z ) ◮ Localize source z ) = ǫ δ (2) ( z − z 2 , ¯ µ ( z, ¯ z − ¯ z 2 ) ◮ 1-point function in µ -vacuum → 2-point function in 0-vacuum � T 1 � µ = � T 1 � 0 + ǫ � T 1 T 2 � 0 + O ( ǫ 2 ) ◮ On gravity side exploit sl (2) CS formulation with chemical potentials A = b − 1 (d+ a ) b b = e ρL 0 a z = L + − L k L − a ¯ z = µL + + . . . ◮ Expand L ( z ) = L (0) ( z ) + ǫ L (1) ( z ) + O ( ǫ 2 ) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 15/25
2-point functions (anomalous terms) Illustrate shortcut in AdS 3 /CFT 2 (restrict to one holomorphic sector) ◮ On gravity side exploit CS formulation with chemical potentials A = b − 1 ( d + a ) b b = e ρL 0 a z = L + − L k L − a ¯ z = µL + + . . . ◮ Expand L ( z ) = L (0) ( z ) + ǫ L (1) ( z ) + O ( ǫ 2 ) ◮ Write EOM to first subleading order in ǫ ∂ L (1) ( z ) = − k ¯ 2 ∂ 3 δ (2) ( z − z 2 ) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 15/25
2-point functions (anomalous terms) Illustrate shortcut in AdS 3 /CFT 2 (restrict to one holomorphic sector) ◮ On gravity side exploit CS formulation with chemical potentials A = b − 1 ( d + a ) b b = e ρL 0 a z = L + − L k L − a ¯ z = µL + + . . . ◮ Expand L ( z ) = L (0) ( z ) + ǫ L (1) ( z ) + O ( ǫ 2 ) ◮ Write EOM to first subleading order in ǫ ∂ L (1) ( z ) = − k ¯ 2 ∂ 3 δ (2) ( z − z 2 ) ◮ Solve them using the Green function on the plane G = ln ( z 12 ¯ z 12 ) L (1) ( z ) = − k z 1 G ( z 12 ) = 3 k 2 ∂ 4 z 4 12 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 15/25
2-point functions (anomalous terms) Illustrate shortcut in AdS 3 /CFT 2 (restrict to one holomorphic sector) ◮ On gravity side exploit CS formulation with chemical potentials A = b − 1 ( d + a ) b b = e ρL 0 a z = L + − L k L − a ¯ z = µL + + . . . ◮ Expand L ( z ) = L (0) ( z ) + ǫ L (1) ( z ) + O ( ǫ 2 ) ◮ Write EOM to first subleading order in ǫ ∂ L (1) ( z ) = − k ¯ 2 ∂ 3 δ (2) ( z − z 2 ) ◮ Solve them using the Green function on the plane G = ln ( z 12 ¯ z 12 ) L (1) ( z ) = − k z 1 G ( z 12 ) = 3 k 2 ∂ 4 z 4 12 ◮ This is the correct CFT 2-point function on the plane with c = 6 k Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 15/25
2-point functions (anomalous terms) Illustrate shortcut in AdS 3 /CFT 2 (restrict to one holomorphic sector) ◮ On gravity side exploit CS formulation with chemical potentials A = b − 1 ( d + a ) b b = e ρL 0 a z = L + − L k L − a ¯ z = µL + + . . . ◮ Expand L ( z ) = L (0) ( z ) + ǫ L (1) ( z ) + O ( ǫ 2 ) ◮ Write EOM to first subleading order in ǫ ∂ L (1) ( z ) = − k ¯ 2 ∂ 3 δ (2) ( z − z 2 ) ◮ Solve them using the Green function on the plane G = ln ( z 12 ¯ z 12 ) L (1) ( z ) = − k z 1 G ( z 12 ) = 3 k 2 ∂ 4 z 4 12 ◮ This is the correct CFT 2-point function on the plane with c = 6 k ◮ Generalize to cylinder Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 15/25
2-point functions (anomalous terms) Apply shortcut to flat space/Galilean CFT (Bagchi, DG, Merbis ’15) ◮ Exploit results for flat space gravity in CS formulation in presence of chemical potentials (Gary, DG, Riegler, Rosseel ’14) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 16/25
2-point functions (anomalous terms) Apply shortcut to flat space/Galilean CFT (Bagchi, DG, Merbis ’15) ◮ Exploit results for flat space gravity in CS formulation in presence of chemical potentials (Gary, DG, Riegler, Rosseel ’14) ◮ Localize chemical potentials µ M/L = ǫ M/L δ (2) ( u − u 2 , ϕ − ϕ 2 ) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 16/25
2-point functions (anomalous terms) Apply shortcut to flat space/Galilean CFT (Bagchi, DG, Merbis ’15) ◮ Exploit results for flat space gravity in CS formulation in presence of chemical potentials (Gary, DG, Riegler, Rosseel ’14) ◮ Localize chemical potentials µ M/L = ǫ M/L δ (2) ( u − u 2 , ϕ − ϕ 2 ) ◮ Expand around global Minkowski space M = − k/ 2 + M (1) N = N (1) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 16/25
2-point functions (anomalous terms) Apply shortcut to flat space/Galilean CFT (Bagchi, DG, Merbis ’15) ◮ Exploit results for flat space gravity in CS formulation in presence of chemical potentials (Gary, DG, Riegler, Rosseel ’14) ◮ Localize chemical potentials µ M/L = ǫ M/L δ (2) ( u − u 2 , ϕ − ϕ 2 ) ◮ Expand around global Minkowski space M = − k/ 2 + M (1) N = N (1) ◮ Write EOM to first subleading order in ǫ M/L � � ∂ u M (1) = − k ǫ L ∂ 3 ϕ δ + ∂ ϕ δ � � ∂ u N (1) = − k ǫ M ∂ 3 + ∂ ϕ M (1) ϕ δ + ∂ ϕ δ Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 16/25
2-point functions (anomalous terms) Apply shortcut to flat space/Galilean CFT (Bagchi, DG, Merbis ’15) ◮ Exploit results for flat space gravity in CS formulation in presence of chemical potentials (Gary, DG, Riegler, Rosseel ’14) ◮ Localize chemical potentials µ M/L = ǫ M/L δ (2) ( u − u 2 , ϕ − ϕ 2 ) ◮ Expand around global Minkowski space M = − k/ 2 + M (1) N = N (1) ◮ Write EOM to first subleading order in ǫ M/L � � ∂ u M (1) = − k ǫ L ∂ 3 ϕ δ + ∂ ϕ δ � � ∂ u N (1) = − k ǫ M ∂ 3 + ∂ ϕ M (1) ϕ δ + ∂ ϕ δ ◮ Solve with Green function on cylinder M (1) = 6 kǫ L N (1) = 6 k ( ǫ M − 2 ǫ L τ 12 ) s 4 s 4 12 12 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 16/25
2-point functions (anomalous terms) Apply shortcut to flat space/Galilean CFT (Bagchi, DG, Merbis ’15) ◮ Exploit results for flat space gravity in CS formulation in presence of chemical potentials (Gary, DG, Riegler, Rosseel ’14) ◮ Localize chemical potentials µ M/L = ǫ M/L δ (2) ( u − u 2 , ϕ − ϕ 2 ) ◮ Expand around global Minkowski space M = − k/ 2 + M (1) N = N (1) ◮ Write EOM to first subleading order in ǫ M/L � � ∂ u M (1) = − k ǫ L ∂ 3 ϕ δ + ∂ ϕ δ � � ∂ u N (1) = − k ǫ M ∂ 3 + ∂ ϕ M (1) ϕ δ + ∂ ϕ δ ◮ Solve with Green function on cylinder M (1) = 6 kǫ L N (1) = 6 k ( ǫ M − 2 ǫ L τ 12 ) s 4 s 4 12 12 ◮ Correct 2-point functions for Einstein gravity with c L = 0 , c M = 12 k Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 16/25
3-point functions (check of symmetries) First non-trivial check of consistency with symmetries of dual Galilean CFT Check of 2-point functions works nicely with shortcut; 3-point too? Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 17/25
3-point functions (check of symmetries) First non-trivial check of consistency with symmetries of dual Galilean CFT Check of 2-point functions works nicely with shortcut; 3-point too? ◮ Yes: same procedure, but localize chemical potentials at two points 3 � ǫ i M/L δ (2) ( u 1 − u i , ϕ 1 − ϕ i ) µ M/L ( u 1 , ϕ 1 ) = i =2 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 17/25
3-point functions (check of symmetries) First non-trivial check of consistency with symmetries of dual Galilean CFT Check of 2-point functions works nicely with shortcut; 3-point too? ◮ Yes: same procedure, but localize chemical potentials at two points 3 � ǫ i M/L δ (2) ( u 1 − u i , ϕ 1 − ϕ i ) µ M/L ( u 1 , ϕ 1 ) = i =2 ◮ Iteratively solve EOM ∂ u M = − k∂ 3 ϕ µ L + µ L ∂ ϕ M + 2 M∂ ϕ µ L ∂ u N = − k∂ 3 ϕ µ M + (1 + µ M ) ∂ ϕ M + 2 M∂ ϕ µ M + µ L ∂ ϕ N + 2 N∂ ϕ µ L Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 17/25
3-point functions (check of symmetries) First non-trivial check of consistency with symmetries of dual Galilean CFT Check of 2-point functions works nicely with shortcut; 3-point too? ◮ Yes: same procedure, but localize chemical potentials at two points 3 � ǫ i M/L δ (2) ( u 1 − u i , ϕ 1 − ϕ i ) µ M/L ( u 1 , ϕ 1 ) = i =2 ◮ Iteratively solve EOM ∂ u M = − k∂ 3 ϕ µ L + µ L ∂ ϕ M + 2 M∂ ϕ µ L ∂ u N = − k∂ 3 ϕ µ M + (1 + µ M ) ∂ ϕ M + 2 M∂ ϕ µ M + µ L ∂ ϕ N + 2 N∂ ϕ µ L ◮ Result on gravity side matches precisely Galilean CFT results c M � N 1 N 2 N 3 � = c L − c M τ 123 � M 1 N 2 N 3 � = s 2 12 s 2 13 s 2 s 2 12 s 2 13 s 2 23 23 provided we choose again the Einstein values c L = 0 and c M = 12 k Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 17/25
4-point functions (enter cross-ratios) First correlators with non-universal function of cross-ratios ◮ Repeat this algorithm, localizing the sources at three points Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 18/25
4-point functions (enter cross-ratios) First correlators with non-universal function of cross-ratios ◮ Repeat this algorithm, localizing the sources at three points ◮ Derive 4-point functions for Galilean CFTs (Bagchi, DG, Merbis ’15) 2 c M g 4 ( γ ) � M 1 N 2 N 3 N 4 � = s 2 14 s 2 23 s 12 s 13 s 24 s 34 � N 1 N 2 N 3 N 4 � = 2 c L g 4 ( γ ) + c M ∆ 4 s 2 14 s 2 23 s 12 s 13 s 24 s 34 with the cross-ratio function g 4 ( γ ) = γ 2 − γ + 1 γ = s 12 s 34 γ s 13 s 24 and ∆ 4 = 4 g ′ 4 ( γ ) η 1234 − ( τ 1234 + τ 14 + τ 23 ) g 4 ( γ ) � ( − 1) 1+ i − j ( u i − u j ) sin( ϕ k − ϕ l ) / ( s 2 13 s 2 η 1234 = 24 ) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 18/25
4-point functions (enter cross-ratios) First correlators with non-universal function of cross-ratios ◮ Repeat this algorithm, localizing the sources at three points ◮ Derive 4-point functions for Galilean CFTs (Bagchi, DG, Merbis ’15) 2 c M g 4 ( γ ) � M 1 N 2 N 3 N 4 � = s 2 14 s 2 23 s 12 s 13 s 24 s 34 � N 1 N 2 N 3 N 4 � = 2 c L g 4 ( γ ) + c M ∆ 4 s 2 14 s 2 23 s 12 s 13 s 24 s 34 with the cross-ratio function g 4 ( γ ) = γ 2 − γ + 1 γ = s 12 s 34 γ s 13 s 24 and ∆ 4 = 4 g ′ 4 ( γ ) η 1234 − ( τ 1234 + τ 14 + τ 23 ) g 4 ( γ ) � ( − 1) 1+ i − j ( u i − u j ) sin( ϕ k − ϕ l ) / ( s 2 13 s 2 η 1234 = 24 ) ◮ Gravity side yields precisely the same result! Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 18/25
5-point functions (further check of consistency of flat space holography) Last new explicit correlators I am showing to you today (I promise) ◮ Repeat this algorithm, localizing the sources at four points Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 19/25
5-point functions (further check of consistency of flat space holography) Last new explicit correlators I am showing to you today (I promise) ◮ Repeat this algorithm, localizing the sources at four points ◮ Derive 5-point functions for Galilean CFTs (Bagchi, DG, Merbis ’15) � M 1 N 2 N 3 N 4 N 5 � = 4 c M g 5 ( γ, ζ ) � 1 ≤ i<j ≤ 5 s ij � N 1 N 2 N 3 N 4 N 5 � = 4 c L g 5 ( γ, ζ ) + c M ∆ 5 � 1 ≤ i<j ≤ 5 s ij with the previous definitions and ( ζ = s 25 s 34 s 35 s 24 ) ( γ 2 − γζ + ζ 2 ) γ + ζ � � g 5 ( γ, ζ ) = [ γ ( γ − 1)+1][ ζ ( ζ − 1)+1] − γζ 2( γ − ζ ) − γ ( γ − 1) ζ ( ζ − 1)( γ − ζ ) × ∆ 5 = 4 ∂ γ g 5 ( γ, ζ ) η 1234 + 4 ∂ ζ g 5 ( γ, ζ ) η 2345 − 2 g 5 ( γ, ζ ) τ 12345 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 19/25
5-point functions (further check of consistency of flat space holography) Last new explicit correlators I am showing to you today (I promise) ◮ Repeat this algorithm, localizing the sources at four points ◮ Derive 5-point functions for Galilean CFTs (Bagchi, DG, Merbis ’15) � M 1 N 2 N 3 N 4 N 5 � = 4 c M g 5 ( γ, ζ ) � 1 ≤ i<j ≤ 5 s ij � N 1 N 2 N 3 N 4 N 5 � = 4 c L g 5 ( γ, ζ ) + c M ∆ 5 � 1 ≤ i<j ≤ 5 s ij with the previous definitions and ( ζ = s 25 s 34 s 35 s 24 ) ( γ 2 − γζ + ζ 2 ) γ + ζ � � g 5 ( γ, ζ ) = [ γ ( γ − 1)+1][ ζ ( ζ − 1)+1] − γζ 2( γ − ζ ) − γ ( γ − 1) ζ ( ζ − 1)( γ − ζ ) × ∆ 5 = 4 ∂ γ g 5 ( γ, ζ ) η 1234 + 4 ∂ ζ g 5 ( γ, ζ ) η 2345 − 2 g 5 ( γ, ζ ) τ 12345 ◮ Gravity side yields precisely the same result! Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 19/25
n -point functions (holographic Ward identities and recursion relations) Shortcut to 42 (Bagchi, DG, Merbis ’15) Smart check of all n -point functions? ◮ Idea: calculate n -point function from ( n − 1) -point function Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 20/25
n -point functions (holographic Ward identities and recursion relations) Shortcut to 42 (Bagchi, DG, Merbis ’15) Smart check of all n -point functions? ◮ Idea: calculate n -point function from ( n − 1) -point function ◮ Need Galilean CFT analogue of BPZ-recursion relation � 2 n � � + c 1 i � T 1 T 2 . . . T n � = � T 2 . . . T n � + disconnected 2 ∂ ϕ i s 2 1 i i =2 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 20/25
n -point functions (holographic Ward identities and recursion relations) Shortcut to 42 (Bagchi, DG, Merbis ’15) Smart check of all n -point functions? ◮ Idea: calculate n -point function from ( n − 1) -point function ◮ Need Galilean CFT analogue of BPZ-recursion relation � 2 n � � + c 1 i � T 1 T 2 . . . T n � = � T 2 . . . T n � + disconnected 2 ∂ ϕ i s 2 1 i i =2 ◮ After small derivation we find ( c ij := cot[( ϕ i − ϕ j ) / 2] ) � 2 � n � + c 1 i � M 1 N 2 . . . N n � = � M 2 N 3 . . . N n � +disconnected 2 ∂ ϕ i s 2 1 i i =2 n � � N 1 N 2 . . . N n � = c L � M 1 N 2 . . . N n � + u i ∂ ϕ i � M 1 N 2 . . . N n � c M i =1 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 20/25
n -point functions (holographic Ward identities and recursion relations) Shortcut to 42 (Bagchi, DG, Merbis ’15) Smart check of all n -point functions? ◮ Idea: calculate n -point function from ( n − 1) -point function ◮ Need Galilean CFT analogue of BPZ-recursion relation � 2 n � � + c 1 i � T 1 T 2 . . . T n � = � T 2 . . . T n � + disconnected 2 ∂ ϕ i s 2 1 i i =2 ◮ After small derivation we find ( c ij := cot[( ϕ i − ϕ j ) / 2] ) � 2 � n � + c 1 i � M 1 N 2 . . . N n � = � M 2 N 3 . . . N n � +disconnected 2 ∂ ϕ i s 2 1 i i =2 n � � N 1 N 2 . . . N n � = c L � M 1 N 2 . . . N n � + u i ∂ ϕ i � M 1 N 2 . . . N n � c M i =1 ◮ We can also derive same recursion relations on gravity side! Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 20/25
n -point functions in flat space holography Summary ◮ EH action has variational principle consistent with flat space bc’s (iff we add half the GHY term!) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 21/25
n -point functions in flat space holography Summary ◮ EH action has variational principle consistent with flat space bc’s (iff we add half the GHY term!) ◮ 0-point function shows phase transition exists between hot flat space and flat space cosmologies Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 21/25
n -point functions in flat space holography Summary ◮ EH action has variational principle consistent with flat space bc’s (iff we add half the GHY term!) ◮ 0-point function shows phase transition exists between hot flat space and flat space cosmologies ◮ 1-point functions show consistency with canonical charges and lead to first entries in holographic dictionary Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 21/25
n -point functions in flat space holography Summary ◮ EH action has variational principle consistent with flat space bc’s (iff we add half the GHY term!) ◮ 0-point function shows phase transition exists between hot flat space and flat space cosmologies ◮ 1-point functions show consistency with canonical charges and lead to first entries in holographic dictionary ◮ 2-point functions consistent with Galilean CFT for c L = 0 , c M = 12 k = 3 /G N Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 21/25
n -point functions in flat space holography Summary ◮ EH action has variational principle consistent with flat space bc’s (iff we add half the GHY term!) ◮ 0-point function shows phase transition exists between hot flat space and flat space cosmologies ◮ 1-point functions show consistency with canonical charges and lead to first entries in holographic dictionary ◮ 2-point functions consistent with Galilean CFT for c L = 0 , c M = 12 k = 3 /G N ◮ 42 nd variation of EH action leads to 42-point Galilean CFT correlators Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 21/25
n -point functions in flat space holography Summary ◮ EH action has variational principle consistent with flat space bc’s (iff we add half the GHY term!) ◮ 0-point function shows phase transition exists between hot flat space and flat space cosmologies ◮ 1-point functions show consistency with canonical charges and lead to first entries in holographic dictionary ◮ 2-point functions consistent with Galilean CFT for c L = 0 , c M = 12 k = 3 /G N ◮ 42 nd variation of EH action leads to 42-point Galilean CFT correlators ◮ all n -point correlators of Galilean CFT reproduced precisely on gravity side (recursion relations!) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 21/25
n -point functions in flat space holography Summary ◮ EH action has variational principle consistent with flat space bc’s (iff we add half the GHY term!) ◮ 0-point function shows phase transition exists between hot flat space and flat space cosmologies ◮ 1-point functions show consistency with canonical charges and lead to first entries in holographic dictionary ◮ 2-point functions consistent with Galilean CFT for c L = 0 , c M = 12 k = 3 /G N ◮ 42 nd variation of EH action leads to 42-point Galilean CFT correlators ◮ all n -point correlators of Galilean CFT reproduced precisely on gravity side (recursion relations!) Fairly non-trivial check that 3D flat space holography can work! Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 21/25
Other selected recent results Some further checks that dual field theory is Galilean CFT: Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 22/25
Other selected recent results Some further checks that dual field theory is Galilean CFT: ◮ Microstate counting? Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 22/25
Other selected recent results Some further checks that dual field theory is Galilean CFT: ◮ Microstate counting? Works! (Bagchi, Detournay, Fareghbal, Simon ’13, Barnich ’13) � c M S gravity = S BH = Area = 2 πh L = S GCFT 4 G N 2 h M Also as limit from Cardy formula (Riegler ’14, Fareghbal, Naseh ’14) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 22/25
Other selected recent results Some further checks that dual field theory is Galilean CFT: ◮ Microstate counting? Works! (Bagchi, Detournay, Fareghbal, Simon ’13, Barnich ’13) � c M S gravity = S BH = Area = 2 πh L = S GCFT 4 G N 2 h M Also as limit from Cardy formula (Riegler ’14, Fareghbal, Naseh ’14) ◮ (Holographic) entanglement entropy? Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 22/25
Other selected recent results Some further checks that dual field theory is Galilean CFT: ◮ Microstate counting? Works! (Bagchi, Detournay, Fareghbal, Simon ’13, Barnich ’13) � c M S gravity = S BH = Area = 2 πh L = S GCFT 4 G N 2 h M Also as limit from Cardy formula (Riegler ’14, Fareghbal, Naseh ’14) ◮ (Holographic) entanglement entropy? Works! (Bagchi, Basu, DG, Riegler ’14) = c L 6 ln ℓ x c M ℓ y S GCFT + EE a 6 ℓ x � �� � � �� � like CFT like grav anomaly Calculation on gravity side confirms result above (using Wilson lines in CS formulation) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Recent results 22/25
Outline Motivations Flat space holography basics Recent results Generalizations & open issues Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Generalizations & open issues 23/25
Generalizations & open issues Recent generalizations: ◮ adding chemical potentials Works! (Gary, DG, Riegler, Rosseel ’14) In CS formulation: A 0 → A 0 + µ Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Generalizations & open issues 24/25
Generalizations & open issues Recent generalizations: ◮ adding chemical potentials ◮ 3-derivative theory: flat space chiral gravity (Bagchi, Detournay, DG ’12) Conformal CS gravity at level k = 1 with flat space boundary conditions conjectured to be dual to chiral half of monster CFT. Action (gravity side): � d 3 x √− g ε λµν Γ ρλσ � � I CSG = k ∂ µ Γ σνρ + 2 3 Γ σµτ Γ τ νρ 4 π Partition function (field theory side, see Witten ’07): Z ( q ) = J ( q ) = 1 q + 196884 q + O ( q 2 ) Note: ln 196883 ≈ 12 . 2 = 4 π + quantum corrections Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Generalizations & open issues 24/25
Generalizations & open issues Recent generalizations: ◮ adding chemical potentials ◮ 3-derivative theory: flat space chiral gravity (Bagchi, Detournay, DG ’12) ◮ generalization to supergravity Works! (Barnich, Donnay, Matulich, Troncoso ’14) Asymptotic symmetry algebra = super-BMS 3 Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Generalizations & open issues 24/25
Generalizations & open issues Recent generalizations: ◮ adding chemical potentials ◮ 3-derivative theory: flat space chiral gravity (Bagchi, Detournay, DG ’12) ◮ generalization to supergravity ◮ flat space higher spin gravity Remarkably it exists! (Afshar, Bagchi, Fareghbal, DG, Rosseel ’13; Gonzalez, Matulich, Pino, Troncoso ’13) New type of algebra: W-like BMS (“BMW”) [ U n , U m ] = ( n − m )(2 n 2 + 2 m 2 − nm − 8) L n + m + 192 c M ( n − m )Λ n + m � c L + 44 � − 96 ( n − m )Θ n + m + c L 12 n ( n 2 − 1)( n 2 − 4) δ n + m, 0 5 c 2 M [ U n , V m ] = ( n − m )(2 n 2 + 2 m 2 − nm − 8) M n + m + 96 c M ( n − m )Θ n + m + c M 12 n ( n 2 − 1)( n 2 − 4) δ n + m, 0 [ L, L ] , [ L, M ] , [ M, M ] as in BMS 3 [ L, U ] , [ L, V ] , [ M, U ] , [ M, V ] as in isl(3) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Generalizations & open issues 24/25
Generalizations & open issues Recent generalizations: ◮ adding chemical potentials ◮ 3-derivative theory: flat space chiral gravity (Bagchi, Detournay, DG ’12) ◮ generalization to supergravity ◮ flat space higher spin gravity Some open issues: ◮ Further checks in 3D ( n -point correlators, partition function, ...) Barnich, Gonzalez, Maloney, Oblak ’15: 1-loop partition function matches BMS 3 character Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Generalizations & open issues 24/25
Generalizations & open issues Recent generalizations: ◮ adding chemical potentials ◮ 3-derivative theory: flat space chiral gravity (Bagchi, Detournay, DG ’12) ◮ generalization to supergravity ◮ flat space higher spin gravity Some open issues: ◮ Further checks in 3D ( n -point correlators, partition function, ...) ◮ Further generalizations in 3D (massive gravity, adding matter, ...) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Generalizations & open issues 24/25
Generalizations & open issues Recent generalizations: ◮ adding chemical potentials ◮ 3-derivative theory: flat space chiral gravity (Bagchi, Detournay, DG ’12) ◮ generalization to supergravity ◮ flat space higher spin gravity Some open issues: ◮ Further checks in 3D ( n -point correlators, partition function, ...) ◮ Further generalizations in 3D (massive gravity, adding matter, ...) ◮ Generalization to 4D? (Barnich et al, Strominger et al) Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Generalizations & open issues 24/25
Generalizations & open issues Recent generalizations: ◮ adding chemical potentials ◮ 3-derivative theory: flat space chiral gravity (Bagchi, Detournay, DG ’12) ◮ generalization to supergravity ◮ flat space higher spin gravity Some open issues: ◮ Further checks in 3D ( n -point correlators, partition function, ...) ◮ Further generalizations in 3D (massive gravity, adding matter, ...) ◮ Generalization to 4D? (Barnich et al, Strominger et al) ◮ Flat space limit of usual AdS 5 /CFT 4 correspondence? Daniel Grumiller — lim ℓ →∞ � AdS 3 / CFT 2 � Generalizations & open issues 24/25
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