Black hole Degeneracies from the effective action Guillaume Bossard - - PowerPoint PPT Presentation

black hole degeneracies from the effective action
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Black hole Degeneracies from the effective action Guillaume Bossard - - PowerPoint PPT Presentation

Black hole Degeneracies from the effective action Guillaume Bossard CPHT, Ecole Polytechnique Texas A & M, April 2018 Outline Heterotic CHL strings and U-duality Protected couplings beyond perturbation theory Decompactification limit and


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Black hole Degeneracies from the effective action

Guillaume Bossard

CPHT, Ecole Polytechnique

Texas A & M, April 2018

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Outline

Heterotic CHL strings and U-duality Protected couplings beyond perturbation theory Decompactification limit and BPS black hole degeneracies

[ G. Bossard, C. Cosnier-Horeau, B. Pioline, 1608.01660 ] [ G. Bossard, C. Cosnier-Horeau, B. Pioline, 1702.01926 ] [ G. Bossard, C. Cosnier-Horeau, B. Pioline, 1805.xxxxx ]

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Motivations

Exact black hole degeneracies from amplitude computations Pioline conjecture: 3D BPS protected amplitudes 4D BPS black holes Black hole degeneracies: Fourier coefficients of modular forms Provides G3 ⊃ G4 modular forms generating functions N = 8 supergravity: ∇6R4 couplings and 1

8 BPS black holes

N = 6 supergravity: ∇2R4 couplings and 1

6 BPS black holes

N = 4 supergravity: ∇2F 4 couplings and 1

4 BPS black holes

Automorphic representation of the coupling from supersymmetry G3 nilpotent orbit associated to the black hole solution Explicit for N = 4 string vacua with a notion of S-duality Orbifolds with balanced frame shape: Fricke S-duality

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Heterotic string theory on T 6

At a generic point in moduli space N = 4 supergravity with scalar manifold SL(2)/SO(2) × SO(6, 22)/(SO(6) × SO(22)) with electric and magnetic charges (Q, P) in Λ6,22 ∼ = I I6,6 ⊕E8 ⊕E8 Also realized as type II on K3×T 2 Heterotic axion-dilaton S Complex structure U on T 2 in type IIB K¨ ahler structure T = B + iV onT 2 in type IIA T-duality O(6, 22, Z) and S-duality SL(2, Z) (T-duality in type II)

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CHL orbifolds

Chauduri, Hockney, Lykken orbifolds: ZN automorphism of the lattice and shift on a circle. ex: Permutation of the two E8 factors and Z2 shift on the circle. For N prime one gets SO(6,

48 N+1 − 2) with

[ Persson, Volpato]

Λ6,22 = I I6,6 ⊕ E8 ⊕ E8 Λ6,14 = I I5,5 ⊕ I I1,1[2] ⊕ E8[2] Λ6,10 = I I3,3 ⊕ I I3,3[3] ⊕ A2 ⊕ A2 Λ6,6 = I I3,3 ⊕ I I3,3[5] Λ6,4 = I I2,2 ⊕ I I2,2[7] ⊕

−4 −1 −1 −2

  • Λ6,2

= I I1,1 ⊕ I I1,1[11] ⊕

    −2 −1 −2 −1 −1 −6 −1 −6    

Λ[N] diagonal embedding Λ ֒ → N

i=1 Λ so (P, P) → N(P, P).

I I1,1[N] is the lattice of momentum m = 0[N] and n ∈ Z.

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U-duality group

At most: Γ ⊂ SL(2, R) × O(6, p) that preserves Λ∗

6,p ⊕ Λ6,p

At least: Heterotic T-duality ˜ O(6, p, Z) automorphism of Λ6,p that stabilizes Λ∗

6,p/Λ6,p

Type II T-duality

Γ1(N)×Γ1(N) automorphism of Λ=I I1,1⊕I I1,1[N] that stabilizes Λ∗/Λ

Γ1(N) × ˜ O(6, p, Z) ⊂ Γ

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U-duality group

At most: Γ ⊂ SL(2, R) × O(6, p) that preserves Λ∗

6,p ⊕ Λ6,p

At most: Heterotic T-duality O(6, p, Z) automorphism of Λ∗

6,p

Type II T-duality

Γ0(N)×Γ0(N)∪F⊗F automorphism of Λ=I I1,1⊕I I1,1[N]

Γ1(N) × ˜ O(6, p, Z) ⊂ Γ0(N) × O(6, p, Z) ⊂ Γ Fricke duality F ⊗ σ ∈ Γ

  • −1

√ N

√ N

  • −1

√ N

√ N

  • =

−1 N

−1 N

1

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U-duality group

N-modular lattice (1-modular is selfdual) Λ6,p There exists σ ∈ O(6, p) such that Λ∗

6,p =

σ √ N Λ6,p then Fricke S-duality (Q, P) →

  • − σ

√ N P, √ Nσ−1Q

  • ,

S → − 1 NS

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1/2 BPS couplings

For SL(2) × SO(6, p) with k = p+2

2

=

24 N+1

− 1 8π2

  • d4x√−g log(Sk

2 |∆k(S)|2)

1 8RµνσρRµνσρ+3t8F aF bFaFb

  • +
  • d4x√−gFabcd(φ)t8F aF bF cF d

with the weight k Γ0(N) cusp form ∆k(τ) = ηk(τ)ηk(Nτ) and Fabcd(φ) =

  • Γ0(N)\H+

d2τ τ 2

2

1 ∆k(τ)ΓΛ6,p[Pabcd] with (function of V (φ) ∈ SO(6, p)/(SO(6) × SO(p)) through the left and right projections, with

Q2

L − Q2 R = (Q, Q) and Q2 L + Q2 R = |V (φ)Q|2)

ΓΛ6,p [Pabcd ] = τ3

2

  • Q∈Λ6,p
  • QLaQLbQLc QLd −

3 2πτ2 δ(abQLc QLd) + 3 (4πτ2)2 δ(abδcd)

  • eiπτQ2

L−iπ ¯ τQ2 R

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1/2 BPS couplings

∆k(τ) = ηk(τ)ηk(Nτ) is Fricke invariant ∆k(− 1 Nτ ) = (−i √ Nτ)k∆k(τ) and so the effective action is invariant under S → − 1

NS and

V (φ) → V (φ)σ, and Fabcd(φσ) =

  • Γ0(N)\H+

d2τ τ 2

2

1 ∆k(τ)ΓσΛ6,p[Pabcd] =

  • Γ0(N)\H+

d2τ τ 2

2

1 ∆k(τ)Γ√

NΛ∗

6,p[Pabcd]

= Fabcd(φ)

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Heterotic string theory on T 7

At a generic point in moduli space N = 8 supergravity with scalar manifold SO(8, 24)/(SO(8) × SO(24)) with U-duality group, the automorphism group O(8, 24, Z) of I I8,8 ⊕ E8 ⊕ E8

[ Sen]

Not the solitons, monodromy of the scalars modulo O(8, 24, Z) In general Γ4 × O(7, 1 + p, Z) ֒ → O(8, 2 + p, Z) the automorphism group of the N-modular non-perturbative lattice Λ8,p+2 = I I1,1 ⊕ I I1,1[N] ⊕ Λ6,p

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Non-pertubative couplings

Supersymmetry implies differential equations O(8, 2 + p, Z) invariance Boundary conditions: cusps (perturbative gs → 0 and decompactification R → ∞) singularities (surfaces of enhanced gauge symmetry) Determines the non-perturbative BPS couplings 1/2 BPS (∇φ)4: 1-loop Fαβγδ(φ) =

  • Γ0(N)\H+

d2τ τ 2

2

1 ∆k(τ)ΓΛ7,p+1[Pαβγδ] 1/4 BPS (∇2φ)(∇φ)2: 2-loop Gαβ,γδ(φ) =

  • Γ0(N)\H+

d6Ω (detΩ2)3 1 Φk−2(Ω)ΓΛ7,p+1[Pαβ,γδ]

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Non-pertubative couplings

Supersymmetry implies differential equations O(8, 2 + p, Z) invariance Boundary conditions: cusps (perturbative gs → 0 and decompactification R → ∞) singularities (surfaces of enhanced gauge symmetry) Determines the non-perturbative BPS couplings

[ Obers Pioline]

1/2 BPS (∇φ)4: Fabcd(φ) =

  • Γ0(N)\H+

d2τ τ 2

2

1 ∆k(τ)ΓΛ8,p+2[Pabcd] 1/4 BPS (∇2φ)(∇φ)2: Gab,cd(φ) =

  • Γ0(N)\H+

d6Ω (detΩ2)3 1 Φk−2(Ω)ΓΛ8,p+2[Pab,cd]

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At large radius

F (8,p+2)

αβγδ

= R2

3 2(2π)2

  • log(S k

2 |∆k(S)|4) − 2k log R

  • δ(αβδγδ) + ˆ

F (6,p)

αβγδ(φ)

  • +4
  • (Q,P)∈Λ∗

6,p⊕Λ6,p Q∧P=0

R4 ¯ c(Q, P)

2

  • ℓ=0

P(ℓ)

αβδγ(QL, PL)

R2ℓ K2−ℓ (2πRM(QR, PR)) M(QR, PR)2−ℓ e2πi(Q·a1+P·a2) +

  • M1=0,M2

P∈Λ6,p

F M1

αβγδ

  • P−M1a1,M2−a1·P+ 1

2 (a1·a1)M1

  • e2πi(P·a2+M1(ψ− 1

2 a1·a2)+(M2−a1·P+ 1 2 (a1·a1)M1)S1)

with

F M1

αβγδ(P, M2) = 4 (R2S2)3 ¯

c(M1, M2, P)

2

  • ℓ=0

˜ P(ℓ)

αβγδ(PL)

(R2S2)ℓ 2π Scl 3

2 −ℓ

K 3

2 −ℓ(Scl)

and the instanton measure (

1 ∆k(τ) = m≥−1 ck(m)e2πimτ)

¯ ck(Q, P) =

  • d≥1

(Q,P)/d ∈Λ∗

6,p⊕Λ6,p

ck

  • − gcd(NQ2,P2,Q·P)

d2

  • +
  • d≥1

(Q,P)/d ∈Λ6,p⊕NΛ∗

6,p

ck

  • − gcd(NQ2,P2,Q·P)

Nd2

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At large radius

F (8,p+2)

αβγδ

= R2

3 2(2π)2

  • log(S k

2 |∆k(S)|4) − 2k log R

  • δ(αβδγδ) + ˆ

F (6,p)

αβγδ(φ)

  • +4
  • (Q,P)∈Λ∗

6,p⊕Λ6,p Q∧P=0

R4 ¯ c(Q, P)

2

  • ℓ=0

P(ℓ)

αβδγ(QL, PL)

R2ℓ K2−ℓ (2πRM(QR, PR)) M(QR, PR)2−ℓ e2πi(Q·a1+P·a2) +

  • M1=0,M2

P∈Λ6,p

F M1

αβγδ

  • P−M1a1,M2−a1·P+ 1

2 (a1·a1)M1

  • e2πi(P·a2+M1(ψ− 1

2 a1·a2)+(M2−a1·P+ 1 2 (a1·a1)M1)S1)

with

F M1

αβγδ(P, M2) = 4 (R2S2)3 ¯

c(M1, M2, P)

2

  • ℓ=0

˜ P(ℓ)

αβγδ(PL)

(R2S2)ℓ 2π Scl 3

2 −ℓ

K 3

2 −ℓ(Scl)

and the instanton measure (

1 ∆k(τ) = m≥−1 ck(m)e2πimτ) ¯ ck(Q, P) =

  • n|N
  • d≥1

(Q,P)/d ∈Λ∗

6,p[n]⊕Λ6,p[n]

ck

  • − gcd(NQ2,P2,Q·P)

nd2

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At large radius

F (8,p+2)

αβγδ

= R2 3 2π ˆ E1(NS) + ˆ E1(S) N + 1 + k 2π log R

  • δ(αβδγδ) + ˆ

F (6,p)

αβγδ(φ)

  • +4
  • (Q,P)∈Λ∗

6,p⊕Λ6,p Q∧P=0

R4 ¯ c(Q, P)

2

  • ℓ=0

P(ℓ)

αβδγ(QL, PL)

R2ℓ K2−ℓ (2πRM(QR, PR)) M(QR, PR)2−ℓ e2πi(Q·a1+P·a2) +

  • M1=0,M2

P∈Λ6,p

F M1

αβγδ

  • P−M1a1,M2−a1·P+ 1

2 (a1·a1)M1

  • e2πi(P·a2+M1(ψ− 1

2 a1·a2)+(M2−a1·P+ 1 2 (a1·a1)M1)S1)

with

F M1

αβγδ(P, M2) = 4 (R2S2)3 ¯

c(M1, M2, P)

2

  • ℓ=0

˜ P(ℓ)

αβγδ(PL)

(R2S2)ℓ 2π Scl 3

2 −ℓ

K 3

2 −ℓ(Scl)

and the instanton measure (

1 ∆k(τ) = m≥−1 ck(m)e2πimτ) ¯ ck(Q, P) =

  • n|N
  • d≥1

(Q,P)/d ∈Λ∗

6,p[n]⊕Λ6,p[n]

ck

  • − gcd(NQ2,P2,Q·P)

nd2

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1/2 BPS dyons

The 1/2 BPS dyons (Q, P) with Q ∧ P = 0 have degeneracy ¯ ck(Q, P) for primitive charges in either Λ∗

6,p ⊕ Λ6,p (n = 1) or

Λ6,p ⊕ NΛ∗

6,p (n = N).

M(QR, PR) is the 1/2 BPS mass of such dyons M(QR, PR) =

  • 2(QR + SPR)(QR + ¯

SPR) S2 and R = e2U|∞ with ds2 = −e2Udt2 + e−2Udxidxi RM(QR, PR) = Scl(Q, P, φ|∞) Instantons are complex saddle points in the path integral

SO(8, p + 2)/(SO(6, 2) × SO(2, p)) ⊂ SO(8, p + 2, C)/(SO(8, C) × SO(p + 2, C))

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Genus 2

The moduli space of genus 2 Riemann surfaces M2,0 ∼ = Sp(4, Z)\Sp(4, R)/U(2) M1,0 ×Z2 M1,0 The Siegel upper half plan minus the separating degeneration locus. Ω = Ω1 + iΩ2, with Ω2 a 2 by 2 positive matrix, with separating degeneration for Ω =

τ1 0 0 τ2

  • .

Genus 2 Narain partition function with symmetrisation

ΓΛq,p [Pab,cd] = det(Ω2)

q 2

  • Qi ∈Λq,p
  • εijεklQL(aiQLb)kQL(cjQLd)l −

3 2π Ω−1ij 2

δab,QLciQLdj +

3 (4π)2detΩ2 δab,δcd

  • eiπΩij QLi QLj −iπ ¯

Ωij QRi QRj

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Siegel modular forms

Φk−2|γ = det(CΩ + D)2−kΦk−2

  • (AΩ + B)(CΩ + D)−1

= Φk−2(Ω) with γ an element A B C D

  • satisfying to

ABT = BAT , DC T = CDT , ADT − BC T = 1 Sp(4, Z) for A, B, C, D are 2 by 2 matrices over Z. Γ0(N) ⊂ Sp(4, Z) for C = 0[N]. Γ1(N) ⊂ Γ0(N) for A = 1[N] and D = 1[N]. Γ(N) ⊂ Γ1(N) for B = 0[N].

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Combining twisted sectors

The observation is that the genus 2 amplitude is gouverned by a single function invariant under Γ0(N) for the lattice Λ7,p+1 = I I1,1[N] ⊕ ˜ Λ6,p = I I1,1 ⊕ Λ6,p , we have

[ D’Hoker and Phong]

Z 00

00

  • =
  • γ∈Sp(4)/Γ0(N)
  • 1

Φk−2 ΓI

I1,1⊕˜ Λ6,p[Pab,cd]

  • γ

Z 00

01

  • =
  • γ∈Γe1/Γ0,e1(N)
  • 1

Φk−2 ΓI

I1,1⊕˜ Λ6,p[e

2πi N n2Pab,cd]

  • γ

and

1 N2

  • hi ,gi ∈Z/(NZ)

Z h1h2

g1g2

  • =
  • γ∈Sp(4)/Γ0(N)
  • 1

Φk−2 1 N2  ΓI

I1,1 ⊕ ˜ Λ6,p[Pab,cd] +

  • γ′ ∈ Γ0(N)/Γ0,e1(N)

ΓI

I1,1 ⊕ ˜ Λ6,p[e

2πi N n2Pab,cd]

  • γ′

 

  • γ
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SLIDE 21

Combining twisted sectors

The observation is that the genus 2 amplitude is gouverned by a single function invariant under Γ0(N) for the lattice Λ7,p+1 = I I1,1[N] ⊕ ˜ Λ6,p , we have

1 N2

  • hi ,gi ∈Z/(NZ)

Z h1h2

g1g2

  • =
  • γ∈Sp(4)/Γ0(N)
  • 1

Φk−2 1 N2  ΓI

I1,1 ⊕ ˜ Λ6,p[Pab,cd] +

  • γ′ ∈ Γ0(N)/Γ0,e1(N)

ΓI

I1,1 ⊕ ˜ Λ6,p[e

2πi N n2Pab,cd]

  • γ′

 

  • γ

=

  • γ∈Sp(4)/Γ0(N)
  • 1

Φk−2 ΓI

I1,1[N] ⊕ ˜ Λ6,p[Pab,cd]

  • γ

and so

Gab,cd =

  • Sp(4)\H+

d6Ω (detΩ2)3 1 N2

  • hi ,gi ∈Z/(NZ)

Z h1h2

g1g2

  • =
  • Γ0(N)\H+

d6Ω (detΩ2)3 1 Φk−2 ΓΛ7,p+1 [Pab,cd ]

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SLIDE 22

Combining twisted sectors

Φ10 from

[ D’Hoker and Phong] .

Computes Φ6 explicitly in Z2 model. Consistancy requires Γ0(N) invariance the splitting at the seperating degeneration Φk−2 τ1 ǫ

ǫ τ2

  • = −(2πǫ)2∆k(τ1)∆k(τ2) + O(ǫ3)

The pole at the maximal degeneration at large Ω2

1 Φk−2(Ω) ∼ e−πitr Ω

  • 2 −1

−1 2

  • + 2e−πitr Ω

2 0 0 0

  • + 2e−πitr Ω

0 0 0 2

  • + 2e−πitr Ω
  • 2 −2

−2 2

  • determines Φk−2 as the known function associated

to the twisted orbifold K3 elliptic genus

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SLIDE 23

At large radius

G (8,p+2)

αβ,γδ

= R4

  • − 1

2π (δαβδγδ − δα(γδδ)β) ˆ E1(NS) + ˆ E1(S) N + 1 2 − 1 4 δαβ, N ˆ E1(NS) − ˆ E1(S) N2 − 1 G (6,p)

γδ (φ) + N ˆ

E1(S) − ˆ E1(NS) N2 − 1 G (6,p)

γδ (φσ)

  • +

G (6,p)

αβ,γδ(φ)

  • −6
  • (Q,P)∈Λ∗

6,p⊕Λ6,p Q∧P=0

R5 ¯ Gαβ,(Q, P, φ)

1

  • ℓ=0

P(ℓ)

δγ(QL, PL)

Rℓ K1−ℓ (2πRM(QR, PR)) M(QR, PR)2−ℓ e2πi(Q·a1+P·a2) +2

  • (Q,P)∈Λ∗

6,p⊕Λ6,p Q∧P=0

R7 ¯ c(Q, P)

2

  • ℓ=0

P(ℓ)

αβ,δγ(QL, PL)

Rℓ B 3

2 −[ ℓ 2 ]

  • 2R2

S2

  • 1

S1 S1 |S|2 Q2

R

QRPR QRPR P2

R

  • |QR ∧ PR|

3 2 −[ ℓ 2 ]

e2πi(Q·a1+P·a2) +

  • M1=0,M2

P∈Λ6,p

G M1

αβ,γδ

  • P−M1a1,M2−a1·P+ 1

2 (a1·a1)M1

  • e2πi(P·a2+M1(ψ− 1

2 a1·a2)+(M2−a1·P+ 1 2 (a1·a1)M1)S1)

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SLIDE 24

At large radius

Matches the heteroric perturbative result

− 1 2π (δαβδγδ − δα(γδδ)β) ˆ E1(NS) + ˆ E1(S) N + 1 2 − 1 4 δαβ, N ˆ E1(NS) − ˆ E1(S) N2 − 1 G (6,p)

γδ (φ) + N ˆ

E1(S) − ˆ E1(NS) N2 − 1 G (6,p)

γδ (φσ)

  • +

G (6,p)

αβ,γδ(φ)

∼ − 1 2πg 4

s

(δαβδγδ − δα(γδδ)β) − 1 4g 2

s

δαβ,G (6,p)

γδ (φ) +

G (6,p)

αβ,γδ(φ)

It is consistant with T-duality in type II perturbation theory

− 1 2π (δαβδγδ − δα(γδδ)β) ˆ E1(NU) + ˆ E1(U) N + 1 2 − 1 4 δαβ, N ˆ E1(NU) − ˆ E1(U) N2 − 1 G (6,p)

γδ (φ) + N ˆ

E1(U) − ˆ E1(NU) N2 − 1 G (6,p)

γδ (φσ)

  • +

G (6,p)

αβ,γδ(φ)

∼ 1 g 4

s

G (4,p−2)

αβ,γδ (φ) + 2N

3g 2

s

(δαβδγδ − δα(γδδ)β) (ˆ

E1(NU)−ˆ E1(U))(ˆ E1(NT)−ˆ E1(T)) N2−1

− 1 4g 2

s

δαβ,

ˆ E1(NU)+ˆ E1(U)+ˆ E1(NT)+ˆ E1(T) N+1

  • G (4,p−2)

γδ

(φ) − 1 2π (δαβδγδ − δα(γδδ)β) ˆ

E1(NU)+ˆ E1(U) N+1

2 + 2

ˆ E1(NU)ˆ E1(NT)+ˆ E1(U)ˆ E1(T) N+1

+ ˆ

E1(NT)+ˆ E1(T) N+1

2

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SLIDE 25

At large radius

Matches the heteroric perturbative result on T 6

− 1 2π (δαβδγδ − δα(γδδ)β)ˆ E1(S) 2 − 1 4 δαβ, ˆ E1(S)G (6,22)

γδ (φ) +

G (6,22)

αβ,γδ(φ)

∼ − 1 2πg 4

s

(δαβδγδ − δα(γδδ)β) − 1 4g 2

s

δαβ,G (6,22)

γδ (φ) +

G (6,22)

αβ,γδ(φ)

and type II perturbation theory on T 2 × K3

− 1 2π (δαβδγδ − δα(γδδ)β)ˆ E1(U) 2 − 1 4 δαβ, ˆ E1(U)G (6,22)

γδ (φ) +

G (6,22)

αβ,γδ(φ)

∼ 1 g 4

s

G (4,20)

αβ,γδ(φ) −

1 4g 2

s

δαβ, ˆ E1(U) + ˆ E1(T) G (4,20)

γδ (φ)

− 1 2π (δαβδγδ − δα(γδδ)β)ˆ E1(U) + ˆ E1(T)2

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SLIDE 26

Fourier coefficients

For detΩ2 large enough

Ck−2 Q2

QP QP P2 , Ω2

  • =
  • (R/Z)3+iΩ2

d3Ω eiπ(Q, P)ΩQ

P

  • Φk−2(Ω)

= C F

k−2

Q2

QP QP P2

  • +
  • γ∈GL(2,Z)

ck(− (dQ−bP)2

2

)ck(− (aP−cQ)2

2

) ×

δ(tr ( 0 1/2 1/2

  • γ⊺Ω2γ))

+ (dQ−bP)·(aP−cQ)

2

(sign(tr ( 0

1/2 1/2

  • γ⊺Ω2γ)) − sign((dQ − dP) · (aP − cQ)))
  • and

Φk−2 = (i √ N)kΦk−2

 −1 1 1 1  

twisted elliptic genus of K3 orbifold

  • Ck−2

Q2

QP QP P2 , Ω2

  • = 1

N

  • (R/Z)2×R/NZ+iΩ2

d3Ω eiπ(Q, P)ΩQ

P

  • Φk−2(Ω)

=

  • C F

k−2

Q2

QP QP P2

  • +
  • γ∈Z2⋉Γ0(N)

ck(− N(dQ−bP)2

2

)ck(− (aP−cQ)2

2

) ×

δ(tr ( 0 1/2 1/2

  • γ⊺Ω2γ))

+ (dQ−bP)·(aP−cQ)

2

(sign(tr ( 0

1/2 1/2

  • γ⊺Ω2γ)) − sign((dQ − dP) · (aP − cQ)))
slide-27
SLIDE 27

Fourier coefficients

The integral

  • P2

d3Ω2 (detΩ2)

3 2 −s e

−πtr

  • Ω−1

2

R2AT

1 S2

  • 1

S1 S1 |S|2

  • A+2Ω2A−1
  • Q2

R

QRPR QRPR P2

R

  • A−T
  • =

2

  • RdetA

2|QR ∧ PR| s Bs

  • 2R2

S2

  • 1

S1 S1 |S|2

  • Q2

R

QRPR QRPR P2

R

  • ,

that behaves as e−2πRM(Q,P) in the limit R → ∞, where

M(Q, P) =

  • 2 |QR +SPR |2

S2

+ 4|QR ∧ PR|

The saddle point is at (for A and B symmetric matrices, detBdetA B−1 = Tr(AB)A − ABA)

Ω2 = R

M(Q, P) A⊺ 1 S2

  • 1

S1 S1 |S|2

  • +

1 |PR ∧QR |

  • |PR|2

−PR · QR −PR · QR |QR|2

A .

slide-28
SLIDE 28

Fourier coefficients

The integral

  • P2

d3Ω2 (detΩ2)

3 2 −s Ck−2

  • Q2

QP QP P2 , Ω2

  • e

−πtr

  • Ω−1

2 R2AT 1 S2

  • 1

S1 S1 |S|2

  • A+2Ω2A−1
  • Q2

R

QRPR QRPR P2

R

  • A−T
  • = 2Ck−2
  • Q2

QP QP P2 , Ω⋆

2

  • RdetA

2|QR ∧ PR| s Bs

  • 2R2

S2

  • 1

S1 S1 |S|2

  • Q2

R

QRPR QRPR P2

R

  • + O(e−2πR(M(Q1,P1)+M(Q2,P2)))

that behaves as e−2πRM(Q,P) in the limit R → ∞, where away from the walls of marginal stability

M(Q, P) < M(Q1, P1) + M(Q2, P2) .

Contour prescription at A = 1

[ Cheng Verlinde]

Ω⋆

2 =

R

M(Q, P)

  • 1

S2

  • 1

S1 S1 |S|2

  • +

1 |PR ∧QR |

  • |PR|2

−PR · QR −PR · QR |QR|2

.

slide-29
SLIDE 29

Fourier coefficients

¯ c(Q, P) =

  • A∈M2(Z)/GL(2,Z)

A−1Q P

  • ∈Λ6,p⊕Λ6,p

detA Ck−2

  • A−1Q2 QP

QP P2

  • A−⊺, A⊺Ω⋆

2A

  • +
  • A∈M2,0(N)/[Z2⋉Γ0(N)]

A−1Q P

  • ∈Λ∗

6,p⊕Λ6,p

detA Ck−2

  • A−1Q2 QP

QP P2

  • A−⊺, A⊺Ω⋆

2A

  • +
  • A∈M2(Z)/GL(2,Z)

A−1 Q P/N

  • ∈Λ∗

6,p⊕Λ∗ 6,p

detA Ck−2

  • A−1NQ2

QP QP P2/N

  • A−⊺, A⊺Ω⋆

2A

slide-30
SLIDE 30

Exact degeneracy

For Heterotic string theory on T 6 ¯ c(Q, P) =

  • A∈M2(Z)/GL(2,Z)

A−1Q P

  • ∈Λ6,22⊕Λ6,22

detA C10

  • A−1Q2 QP

QP P2

  • A−⊺, A⊺Ω⋆

2A

  • For a primitive electromagnetic charge (Q, P),

SL(2, Z) × O(6, 22, Z) permits to chose a representative Q = qe1 , P = pe1 + e2 , Q ∧ P = qe1 ∧ e2 for primitive vectors e1 and e2 in Λ6,22 and q, p integers. ¯ c(Q, P) =

  • d|q

d C10 Q2/d2 QP/d

QP/d P2

  • ,

d 0

0 1

  • Ω⋆

2

d 0

0 1

  • reproduces the

[ Dabholkar Gomes Murthy]

generalisation of

[ Dijkgraaf Verlinde Verlinde]

(mod contour prescription).

slide-31
SLIDE 31

Exact degeneracy

For twisted charges with Q⊂Λ∗

6,p and P⊂Λ6,p

¯ c(Q, P) =

  • A∈M2,0(N)/[Z2⋉Γ0(N)]

A−1Q P

  • ∈Λ∗

6,p⊕Λ6,p

detA Ck−2

  • A−1Q2 QP

QP P2

  • A−⊺, A⊺Ω⋆

2A

  • For both Q and P primitive and gcd(Q ∧ P) = 1,

Q = e1 + re2 , P = e2 , Q ∧ P = e1 ∧ e2 for primitive vectors e1 ∈ Λ∗

6,p and e2 ∈ Λ6,p and

¯ c(Q, P) = Ck−2 Q2 QP

QP P2

  • , Ω⋆

2

  • reproduces

[ Jatkar Sen] .

slide-32
SLIDE 32

Supersymmetry Ward identities

1/2 BPS coupling

  • d8θf (W a+) gives the constraints

(Wavefrontset: nilpotent orbit Λ1 ∈ so8,p+2, Υ1 ∈ so8)

D[e

[ˆ eDf ] ˆ f ]Fabcd

= 0 , D[e

ˆ aFa]bcd = 0 ,

D(e

ˆ gDf )ˆ g Fabcd

= − 3

2 δef Fabcd − 4 δe)(a Fbcd)(f + 3 δ(ab Fcd)ef .

1/4 BPS coupling d12θf (W a+1, W a+2) gives the constraints (Wavefrontset: nilpotent orbit 2Λ2 ∈ so8,p+2, 2Υ2 ∈ so8)

D[a1

ˆ aGa2|b|,a3]c = 0 ,

D[a1

[ˆ a1Da2 ˆ a2]Ga3]b,cd = 0 ,

D[a1

[ˆ a1Da2 ˆ a2Da3] ˆ a3]Gcd,ef = 0 ,

and the inhomogeneous equation

D(e

ˆ aDf )ˆ aGab,cd = − 5 2 δef Gab,cd − δe)(aGb)(f ,cd − δe)(cGd)(f ,ab + 3 2 δab,Gcd,ef

− π Fab(e

gFf )cdg − Fe)a(c gFd)bg(f

  • .
slide-33
SLIDE 33

Supersymmetry Ward identities

D(e

ˆ aDf )ˆ aGab,cd + 5 2 δef Gab,cd + δe)(aGb)(f ,cd + δe)(cGd)(f ,ab + 3 2 δab,Gcd,ef

= −π Fab(e

gFf )cdg − Fe)a(c gFd)bg(f

  • Consistant with

G (8,p+2)

αβ,γδ

∼ R4

  • − 1

2π (δαβδγδ − δα(γδδ)β) ˆ E1(NS) + ˆ E1(S) N + 1 2 − 1 4 δαβ, N ˆ E1(NS) − ˆ E1(S) N2 − 1 G (6,p)

γδ (φ) + N ˆ

E1(S) − ˆ E1(NS) N2 − 1 G (6,p)

γδ (φσ)

  • +

G (6,p)

αβ,γδ(φ)

  • and

F (8,p+2)

αβγδ

∼ R2 3 2π ˆ E1(NS) + ˆ E1(S) N + 1 δ(αβδγδ) + ˆ F (6,p)

αβγδ(φ)

slide-34
SLIDE 34

Supersymmetry Ward identities

D(e

ˆ aDf )ˆ aGab,cd + 5 2 δef Gab,cd + δe)(aGb)(f ,cd + δe)(cGd)(f ,ab + 3 2 δab,Gcd,ef

= −π Fab(e

gFf )cdg − Fe)a(c gFd)bg(f

  • Consistant with

G(8,p+2) αβ,γδ ∼ 2

  • (Q,P)∈Λ∗

6,p⊕Λ6,p Q∧P=0 R7 ¯ c(Q, P) 2

  • ℓ=0

P(ℓ) αβ,δγ (QL, PL) Rℓ B 3 2 −[ ℓ 2 ]

  • 2R2

S2

  • 1

S1 S1 |S|2 Q2 R QR PR QR PR P2 R

  • |QR ∧ PR |

3 2 −[ ℓ 2 ] e2πi(Q·a1+P·a2)

and Q

P

  • = A

1 0

0 0

  • A−1Q

P

  • + A

0 0

0 1

  • A−1Q

P

  • F (8,p+2)

αβγδ

∼ 4

  • (Q,P)∈Λ∗

6,p⊕Λ6,p Q∧P=0

R4 ¯ c(Q, P)

2

  • ℓ=0

P(ℓ)

αβδγ(QL, PL)

R2ℓ K2−ℓ (2πRM(QR, PR)) M(QR, PR)2−ℓ e2πi(Q·a1+P·a2)

slide-35
SLIDE 35

Conclusion

U-duality in CHL orbifolds: Automorphisms of Λ8,p+2 = I I1,1 ⊕ I I1,1[N] ⊕ Λ6,p Exact Fabcd and Gab,cd couplings Extend the Narain lattice to Λ8,p+2 We provided strong evidences for N prime Generalisation to balanced frame shape is natural More general frame shapes require gluing vectors The coupling Gab,cd provides a O(8, p + 2, Z) invariant generating function for 1/4 BPS black hole degeneracies Corroborate and generalise the exact degeneracies Wall crossing incorporated in the differential equation N = 8 similar and N = 6 possibly.