Some nonstandard gravity setups in AdS/CFT Romuald A. Janik - - PowerPoint PPT Presentation

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Some nonstandard gravity setups in AdS/CFT Romuald A. Janik - - PowerPoint PPT Presentation

Some nonstandard gravity setups in AdS/CFT Romuald A. Janik Jagiellonian University Krakw M. Heller, RJ, P. Witaszczyk, 1103.3452, 1203.0755 RJ, J. Jankowski, P. Witkowski, work in progress 1 / 24 Outline Introduction: Global AdS versus


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SLIDE 1

Some nonstandard gravity setups in AdS/CFT

Romuald A. Janik

Jagiellonian University Kraków

  • M. Heller, RJ, P. Witaszczyk, 1103.3452, 1203.0755

RJ, J. Jankowski, P. Witkowski, work in progress

1 / 24

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SLIDE 2

Outline Introduction: Global AdS versus Poincare Patch Outer boundary conditions (in the bulk) – freezing the evolution Subtleties with ADM at the AdS boundary Dirac δ-like boundary conditions Conclusions

2 / 24

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SLIDE 3

Global AdS versus Poincare Patch Global AdS5 ds2 = − cosh2 ρ dτ 2+dρ2+sinh2 ρ dΩ2

3

Poincare patch ds2 = ηµνdxµdxν + dz2 z2

◮ Poincare patch covers only a part of the global Anti-de-Sitter

spacetime

◮ In AdS/CFT a crucial role is played by the boundary

– in the global AdS case it is R × S3 – for the Poincare patch it is R1,3

◮ This provides a quite different physical interpretation on the gauge

theory side: – in the global AdS case we are dealing with N = 4 SYM theory on R × S3 – for Poincare patch we are dealing with N = 4 SYM theory on R1,3

3 / 24

slide-4
SLIDE 4

Global AdS versus Poincare Patch Global AdS5 ds2 = − cosh2 ρ dτ 2+dρ2+sinh2 ρ dΩ2

3

Poincare patch ds2 = ηµνdxµdxν + dz2 z2

◮ Poincare patch covers only a part of the global Anti-de-Sitter

spacetime

◮ In AdS/CFT a crucial role is played by the boundary

– in the global AdS case it is R × S3 – for the Poincare patch it is R1,3

◮ This provides a quite different physical interpretation on the gauge

theory side: – in the global AdS case we are dealing with N = 4 SYM theory on R × S3 – for Poincare patch we are dealing with N = 4 SYM theory on R1,3

3 / 24

slide-5
SLIDE 5

Global AdS versus Poincare Patch Global AdS5 ds2 = − cosh2 ρ dτ 2+dρ2+sinh2 ρ dΩ2

3

Poincare patch ds2 = ηµνdxµdxν + dz2 z2

◮ Poincare patch covers only a part of the global Anti-de-Sitter

spacetime

◮ In AdS/CFT a crucial role is played by the boundary

– in the global AdS case it is R × S3 – for the Poincare patch it is R1,3

◮ This provides a quite different physical interpretation on the gauge

theory side: – in the global AdS case we are dealing with N = 4 SYM theory on R × S3 – for Poincare patch we are dealing with N = 4 SYM theory on R1,3

3 / 24

slide-6
SLIDE 6

Global AdS versus Poincare Patch Global AdS5 ds2 = − cosh2 ρ dτ 2+dρ2+sinh2 ρ dΩ2

3

Poincare patch ds2 = ηµνdxµdxν + dz2 z2

◮ Poincare patch covers only a part of the global Anti-de-Sitter

spacetime

◮ In AdS/CFT a crucial role is played by the boundary

– in the global AdS case it is R × S3 – for the Poincare patch it is R1,3

◮ This provides a quite different physical interpretation on the gauge

theory side: – in the global AdS case we are dealing with N = 4 SYM theory on R × S3 – for Poincare patch we are dealing with N = 4 SYM theory on R1,3

3 / 24

slide-7
SLIDE 7

Global AdS versus Poincare Patch Global AdS5 ds2 = − cosh2 ρ dτ 2+dρ2+sinh2 ρ dΩ2

3

Poincare patch ds2 = ηµνdxµdxν + dz2 z2

◮ Poincare patch covers only a part of the global Anti-de-Sitter

spacetime

◮ In AdS/CFT a crucial role is played by the boundary

– in the global AdS case it is R × S3 – for the Poincare patch it is R1,3

◮ This provides a quite different physical interpretation on the gauge

theory side: – in the global AdS case we are dealing with N = 4 SYM theory on R × S3 – for Poincare patch we are dealing with N = 4 SYM theory on R1,3

3 / 24

slide-8
SLIDE 8

Global AdS versus Poincare Patch Global AdS5 ds2 = − cosh2 ρ dτ 2+dρ2+sinh2 ρ dΩ2

3

Poincare patch ds2 = ηµνdxµdxν + dz2 z2

◮ Poincare patch covers only a part of the global Anti-de-Sitter

spacetime

◮ In AdS/CFT a crucial role is played by the boundary

– in the global AdS case it is R × S3 – for the Poincare patch it is R1,3

◮ This provides a quite different physical interpretation on the gauge

theory side: – in the global AdS case we are dealing with N = 4 SYM theory on R × S3 – for Poincare patch we are dealing with N = 4 SYM theory on R1,3

3 / 24

slide-9
SLIDE 9

Global AdS versus Poincare Patch Global AdS5 ds2 = − cosh2 ρ dτ 2+dρ2+sinh2 ρ dΩ2

3

Poincare patch ds2 = ηµνdxµdxν + dz2 z2

◮ Poincare patch covers only a part of the global Anti-de-Sitter

spacetime

◮ In AdS/CFT a crucial role is played by the boundary

– in the global AdS case it is R × S3 – for the Poincare patch it is R1,3

◮ This provides a quite different physical interpretation on the gauge

theory side: – in the global AdS case we are dealing with N = 4 SYM theory on R × S3 – for Poincare patch we are dealing with N = 4 SYM theory on R1,3

3 / 24

slide-10
SLIDE 10

Global AdS versus Poincare Patch Global AdS5 ds2 = − cosh2 ρ dτ 2+dρ2+sinh2 ρ dΩ2

3

Poincare patch ds2 = ηµνdxµdxν + dz2 z2

◮ Poincare patch covers only a part of the global Anti-de-Sitter

spacetime

◮ In AdS/CFT a crucial role is played by the boundary

– in the global AdS case it is R × S3 – for the Poincare patch it is R1,3

◮ This provides a quite different physical interpretation on the gauge

theory side: – in the global AdS case we are dealing with N = 4 SYM theory on R × S3 – for Poincare patch we are dealing with N = 4 SYM theory on R1,3

3 / 24

slide-11
SLIDE 11

Global AdS versus Poincare Patch Global AdS5 ds2 = − cosh2 ρ dτ 2+dρ2+sinh2 ρ dΩ2

3

Poincare patch ds2 = ηµνdxµdxν + dz2 z2

◮ Poincare patch covers only a part of the global Anti-de-Sitter

spacetime

◮ In AdS/CFT a crucial role is played by the boundary

– in the global AdS case it is R × S3 – for the Poincare patch it is R1,3

◮ This provides a quite different physical interpretation on the gauge

theory side: – in the global AdS case we are dealing with N = 4 SYM theory on R × S3 – for Poincare patch we are dealing with N = 4 SYM theory on R1,3

3 / 24

slide-12
SLIDE 12

Global AdS versus Poincare Patch Global AdS5 ds2 = − cosh2 ρ dτ 2+dρ2+sinh2 ρ dΩ2

3

Poincare patch ds2 = ηµνdxµdxν + dz2 z2

◮ Poincare patch covers only a part of the global Anti-de-Sitter

spacetime

◮ In AdS/CFT a crucial role is played by the boundary

– in the global AdS case it is R × S3 – for the Poincare patch it is R1,3

◮ This provides a quite different physical interpretation on the gauge

theory side: – in the global AdS case we are dealing with N = 4 SYM theory on R × S3 – for Poincare patch we are dealing with N = 4 SYM theory on R1,3

3 / 24

slide-13
SLIDE 13

Global AdS versus Poincare Patch Global AdS5 ds2 = − cosh2 ρ dτ 2+dρ2+sinh2 ρ dΩ2

3

Poincare patch ds2 = ηµνdxµdxν + dz2 z2

◮ Poincare patch covers only a part of the global Anti-de-Sitter

spacetime

◮ In AdS/CFT a crucial role is played by the boundary

– in the global AdS case it is R × S3 – for the Poincare patch it is R1,3

◮ This provides a quite different physical interpretation on the gauge

theory side: – in the global AdS case we are dealing with N = 4 SYM theory on R × S3 – for Poincare patch we are dealing with N = 4 SYM theory on R1,3

3 / 24

slide-14
SLIDE 14

Global AdS versus Poincare Patch Global AdS5 ds2 = − cosh2 ρ dτ 2+dρ2+sinh2 ρ dΩ2

3

Poincare patch ds2 = ηµνdxµdxν + dz2 z2

◮ Poincare patch covers only a part of the global Anti-de-Sitter

spacetime

◮ In AdS/CFT a crucial role is played by the boundary

– in the global AdS case it is R × S3 – for the Poincare patch it is R1,3

◮ This provides a quite different physical interpretation on the gauge

theory side: – in the global AdS case we are dealing with N = 4 SYM theory on R × S3 – for Poincare patch we are dealing with N = 4 SYM theory on R1,3

3 / 24

slide-15
SLIDE 15

Global AdS versus Poincare Patch

◮ The two theories, i.e. N = 4 SYM on R × S3 and on R1,3 are

closely related but nevertheless exhibit different physics

◮ R × S3 has finite spatial volume (with scale set by the size of the S3) ◮ The gauge theory exhibits a phase transition ◮ The spectrum of the hamiltonian is discrete (these are (anomalous)

dimensions of local operators of the theory on R1,3)

◮ The theory on R1,3 is efectively in infinite volume and has no scale ◮ There is no phase transition ◮ The spectrum of the hamiltonian is continous ◮ The properties of e.g thermalization may be quite different

4 / 24

slide-16
SLIDE 16

Global AdS versus Poincare Patch

◮ The two theories, i.e. N = 4 SYM on R × S3 and on R1,3 are

closely related but nevertheless exhibit different physics

◮ R × S3 has finite spatial volume (with scale set by the size of the S3) ◮ The gauge theory exhibits a phase transition ◮ The spectrum of the hamiltonian is discrete (these are (anomalous)

dimensions of local operators of the theory on R1,3)

◮ The theory on R1,3 is efectively in infinite volume and has no scale ◮ There is no phase transition ◮ The spectrum of the hamiltonian is continous ◮ The properties of e.g thermalization may be quite different

4 / 24

slide-17
SLIDE 17

Global AdS versus Poincare Patch

◮ The two theories, i.e. N = 4 SYM on R × S3 and on R1,3 are

closely related but nevertheless exhibit different physics

◮ R × S3 has finite spatial volume (with scale set by the size of the S3) ◮ The gauge theory exhibits a phase transition ◮ The spectrum of the hamiltonian is discrete (these are (anomalous)

dimensions of local operators of the theory on R1,3)

◮ The theory on R1,3 is efectively in infinite volume and has no scale ◮ There is no phase transition ◮ The spectrum of the hamiltonian is continous ◮ The properties of e.g thermalization may be quite different

4 / 24

slide-18
SLIDE 18

Global AdS versus Poincare Patch

◮ The two theories, i.e. N = 4 SYM on R × S3 and on R1,3 are

closely related but nevertheless exhibit different physics

◮ R × S3 has finite spatial volume (with scale set by the size of the S3) ◮ The gauge theory exhibits a phase transition ◮ The spectrum of the hamiltonian is discrete (these are (anomalous)

dimensions of local operators of the theory on R1,3)

◮ The theory on R1,3 is efectively in infinite volume and has no scale ◮ There is no phase transition ◮ The spectrum of the hamiltonian is continous ◮ The properties of e.g thermalization may be quite different

4 / 24

slide-19
SLIDE 19

Global AdS versus Poincare Patch

◮ The two theories, i.e. N = 4 SYM on R × S3 and on R1,3 are

closely related but nevertheless exhibit different physics

◮ R × S3 has finite spatial volume (with scale set by the size of the S3) ◮ The gauge theory exhibits a phase transition ◮ The spectrum of the hamiltonian is discrete (these are (anomalous)

dimensions of local operators of the theory on R1,3)

◮ The theory on R1,3 is efectively in infinite volume and has no scale ◮ There is no phase transition ◮ The spectrum of the hamiltonian is continous ◮ The properties of e.g thermalization may be quite different

4 / 24

slide-20
SLIDE 20

Global AdS versus Poincare Patch

◮ The two theories, i.e. N = 4 SYM on R × S3 and on R1,3 are

closely related but nevertheless exhibit different physics

◮ R × S3 has finite spatial volume (with scale set by the size of the S3) ◮ The gauge theory exhibits a phase transition ◮ The spectrum of the hamiltonian is discrete (these are (anomalous)

dimensions of local operators of the theory on R1,3)

◮ The theory on R1,3 is efectively in infinite volume and has no scale ◮ There is no phase transition ◮ The spectrum of the hamiltonian is continous ◮ The properties of e.g thermalization may be quite different

4 / 24

slide-21
SLIDE 21

Global AdS versus Poincare Patch

◮ The two theories, i.e. N = 4 SYM on R × S3 and on R1,3 are

closely related but nevertheless exhibit different physics

◮ R × S3 has finite spatial volume (with scale set by the size of the S3) ◮ The gauge theory exhibits a phase transition ◮ The spectrum of the hamiltonian is discrete (these are (anomalous)

dimensions of local operators of the theory on R1,3)

◮ The theory on R1,3 is efectively in infinite volume and has no scale ◮ There is no phase transition ◮ The spectrum of the hamiltonian is continous ◮ The properties of e.g thermalization may be quite different

4 / 24

slide-22
SLIDE 22

Global AdS versus Poincare Patch

◮ The two theories, i.e. N = 4 SYM on R × S3 and on R1,3 are

closely related but nevertheless exhibit different physics

◮ R × S3 has finite spatial volume (with scale set by the size of the S3) ◮ The gauge theory exhibits a phase transition ◮ The spectrum of the hamiltonian is discrete (these are (anomalous)

dimensions of local operators of the theory on R1,3)

◮ The theory on R1,3 is efectively in infinite volume and has no scale ◮ There is no phase transition ◮ The spectrum of the hamiltonian is continous ◮ The properties of e.g thermalization may be quite different

4 / 24

slide-23
SLIDE 23

Global AdS versus Poincare Patch

◮ The two theories, i.e. N = 4 SYM on R × S3 and on R1,3 are

closely related but nevertheless exhibit different physics

◮ R × S3 has finite spatial volume (with scale set by the size of the S3) ◮ The gauge theory exhibits a phase transition ◮ The spectrum of the hamiltonian is discrete (these are (anomalous)

dimensions of local operators of the theory on R1,3)

◮ The theory on R1,3 is efectively in infinite volume and has no scale ◮ There is no phase transition ◮ The spectrum of the hamiltonian is continous ◮ The properties of e.g thermalization may be quite different

4 / 24

slide-24
SLIDE 24

Global AdS versus Poincare Patch

◮ The two theories, i.e. N = 4 SYM on R × S3 and on R1,3 are

closely related but nevertheless exhibit different physics

◮ R × S3 has finite spatial volume (with scale set by the size of the S3) ◮ The gauge theory exhibits a phase transition ◮ The spectrum of the hamiltonian is discrete (these are (anomalous)

dimensions of local operators of the theory on R1,3)

◮ The theory on R1,3 is efectively in infinite volume and has no scale ◮ There is no phase transition ◮ The spectrum of the hamiltonian is continous ◮ The properties of e.g thermalization may be quite different

4 / 24

slide-25
SLIDE 25

Global AdS versus Poincare Patch

◮ Sometimes one can interpret results from both perspectives... ◮ ... however a natural physical configuration/problem in one

perspective may be bizarre (or not very natural) in the other perspective

◮ Moreover some natural initial conditions in the Poincare context do

not extend to smooth configurations in the global context (e.g. periodic configurations)

◮ There are fascinating questions in both contexts!

This talk: Three examples of complications/stumbling blocks in various setups within the Poincare patch context...

as encountered by an outsider in NR...

5 / 24

slide-26
SLIDE 26

Global AdS versus Poincare Patch

◮ Sometimes one can interpret results from both perspectives... ◮ ... however a natural physical configuration/problem in one

perspective may be bizarre (or not very natural) in the other perspective

◮ Moreover some natural initial conditions in the Poincare context do

not extend to smooth configurations in the global context (e.g. periodic configurations)

◮ There are fascinating questions in both contexts!

This talk: Three examples of complications/stumbling blocks in various setups within the Poincare patch context...

as encountered by an outsider in NR...

5 / 24

slide-27
SLIDE 27

Global AdS versus Poincare Patch

◮ Sometimes one can interpret results from both perspectives... ◮ ... however a natural physical configuration/problem in one

perspective may be bizarre (or not very natural) in the other perspective

◮ Moreover some natural initial conditions in the Poincare context do

not extend to smooth configurations in the global context (e.g. periodic configurations)

◮ There are fascinating questions in both contexts!

This talk: Three examples of complications/stumbling blocks in various setups within the Poincare patch context...

as encountered by an outsider in NR...

5 / 24

slide-28
SLIDE 28

Global AdS versus Poincare Patch

◮ Sometimes one can interpret results from both perspectives... ◮ ... however a natural physical configuration/problem in one

perspective may be bizarre (or not very natural) in the other perspective

◮ Moreover some natural initial conditions in the Poincare context do

not extend to smooth configurations in the global context (e.g. periodic configurations)

◮ There are fascinating questions in both contexts!

This talk: Three examples of complications/stumbling blocks in various setups within the Poincare patch context...

as encountered by an outsider in NR...

5 / 24

slide-29
SLIDE 29

Global AdS versus Poincare Patch

◮ Sometimes one can interpret results from both perspectives... ◮ ... however a natural physical configuration/problem in one

perspective may be bizarre (or not very natural) in the other perspective

◮ Moreover some natural initial conditions in the Poincare context do

not extend to smooth configurations in the global context (e.g. periodic configurations)

◮ There are fascinating questions in both contexts!

This talk: Three examples of complications/stumbling blocks in various setups within the Poincare patch context...

as encountered by an outsider in NR...

5 / 24

slide-30
SLIDE 30

Global AdS versus Poincare Patch

◮ Sometimes one can interpret results from both perspectives... ◮ ... however a natural physical configuration/problem in one

perspective may be bizarre (or not very natural) in the other perspective

◮ Moreover some natural initial conditions in the Poincare context do

not extend to smooth configurations in the global context (e.g. periodic configurations)

◮ There are fascinating questions in both contexts!

This talk: Three examples of complications/stumbling blocks in various setups within the Poincare patch context...

as encountered by an outsider in NR...

5 / 24

slide-31
SLIDE 31

Global AdS versus Poincare Patch

◮ Sometimes one can interpret results from both perspectives... ◮ ... however a natural physical configuration/problem in one

perspective may be bizarre (or not very natural) in the other perspective

◮ Moreover some natural initial conditions in the Poincare context do

not extend to smooth configurations in the global context (e.g. periodic configurations)

◮ There are fascinating questions in both contexts!

This talk: Three examples of complications/stumbling blocks in various setups within the Poincare patch context...

as encountered by an outsider in NR...

5 / 24

slide-32
SLIDE 32

Global AdS versus Poincare Patch

◮ Sometimes one can interpret results from both perspectives... ◮ ... however a natural physical configuration/problem in one

perspective may be bizarre (or not very natural) in the other perspective

◮ Moreover some natural initial conditions in the Poincare context do

not extend to smooth configurations in the global context (e.g. periodic configurations)

◮ There are fascinating questions in both contexts!

This talk: Three examples of complications/stumbling blocks in various setups within the Poincare patch context...

as encountered by an outsider in NR...

5 / 24

slide-33
SLIDE 33

Global AdS versus Poincare Patch

◮ Sometimes one can interpret results from both perspectives... ◮ ... however a natural physical configuration/problem in one

perspective may be bizarre (or not very natural) in the other perspective

◮ Moreover some natural initial conditions in the Poincare context do

not extend to smooth configurations in the global context (e.g. periodic configurations)

◮ There are fascinating questions in both contexts!

This talk: Three examples of complications/stumbling blocks in various setups within the Poincare patch context...

as encountered by an outsider in NR...

5 / 24

slide-34
SLIDE 34
  • I. Outer boundary conditions (in the bulk)
  • M. Heller, RJ, P. Witaszczyk

Physical context: Study the evolution of a strongly coupled plasma system from various initial conditions until a hydrodynamic description becomes accurate... Method: Describe the time dependent evolving strongly coupled plasma system through a dual 5D geometry — given e.g. by ds2 = gµν(xρ, z)dxµdxν + dz2 z2 ≡ g 5D

αβdxαdxβ

i) use Einstein’s equations for the time evolution Rαβ − 1 2g 5D

αβR − 6 g 5D αβ = 0

ii) read off Tµν(xρ) from the numerical metric gµν(xρ, z) gµν(xρ, z) = ηµν + z4g (4)

µν (xρ) + . . .

Tµν(xρ) = N2

c

2π2 · g (4)

µν (xρ)

6 / 24

slide-35
SLIDE 35
  • I. Outer boundary conditions (in the bulk)
  • M. Heller, RJ, P. Witaszczyk

Physical context: Study the evolution of a strongly coupled plasma system from various initial conditions until a hydrodynamic description becomes accurate... Method: Describe the time dependent evolving strongly coupled plasma system through a dual 5D geometry — given e.g. by ds2 = gµν(xρ, z)dxµdxν + dz2 z2 ≡ g 5D

αβdxαdxβ

i) use Einstein’s equations for the time evolution Rαβ − 1 2g 5D

αβR − 6 g 5D αβ = 0

ii) read off Tµν(xρ) from the numerical metric gµν(xρ, z) gµν(xρ, z) = ηµν + z4g (4)

µν (xρ) + . . .

Tµν(xρ) = N2

c

2π2 · g (4)

µν (xρ)

6 / 24

slide-36
SLIDE 36
  • I. Outer boundary conditions (in the bulk)
  • M. Heller, RJ, P. Witaszczyk

Physical context: Study the evolution of a strongly coupled plasma system from various initial conditions until a hydrodynamic description becomes accurate... Method: Describe the time dependent evolving strongly coupled plasma system through a dual 5D geometry — given e.g. by ds2 = gµν(xρ, z)dxµdxν + dz2 z2 ≡ g 5D

αβdxαdxβ

i) use Einstein’s equations for the time evolution Rαβ − 1 2g 5D

αβR − 6 g 5D αβ = 0

ii) read off Tµν(xρ) from the numerical metric gµν(xρ, z) gµν(xρ, z) = ηµν + z4g (4)

µν (xρ) + . . .

Tµν(xρ) = N2

c

2π2 · g (4)

µν (xρ)

6 / 24

slide-37
SLIDE 37
  • I. Outer boundary conditions (in the bulk)
  • M. Heller, RJ, P. Witaszczyk

Physical context: Study the evolution of a strongly coupled plasma system from various initial conditions until a hydrodynamic description becomes accurate... Method: Describe the time dependent evolving strongly coupled plasma system through a dual 5D geometry — given e.g. by ds2 = gµν(xρ, z)dxµdxν + dz2 z2 ≡ g 5D

αβdxαdxβ

i) use Einstein’s equations for the time evolution Rαβ − 1 2g 5D

αβR − 6 g 5D αβ = 0

ii) read off Tµν(xρ) from the numerical metric gµν(xρ, z) gµν(xρ, z) = ηµν + z4g (4)

µν (xρ) + . . .

Tµν(xρ) = N2

c

2π2 · g (4)

µν (xρ)

6 / 24

slide-38
SLIDE 38
  • I. Outer boundary conditions (in the bulk)
  • M. Heller, RJ, P. Witaszczyk

Physical context: Study the evolution of a strongly coupled plasma system from various initial conditions until a hydrodynamic description becomes accurate... Method: Describe the time dependent evolving strongly coupled plasma system through a dual 5D geometry — given e.g. by ds2 = gµν(xρ, z)dxµdxν + dz2 z2 ≡ g 5D

αβdxαdxβ

i) use Einstein’s equations for the time evolution Rαβ − 1 2g 5D

αβR − 6 g 5D αβ = 0

ii) read off Tµν(xρ) from the numerical metric gµν(xρ, z) gµν(xρ, z) = ηµν + z4g (4)

µν (xρ) + . . .

Tµν(xρ) = N2

c

2π2 · g (4)

µν (xρ)

6 / 24

slide-39
SLIDE 39
  • I. Outer boundary conditions (in the bulk)
  • M. Heller, RJ, P. Witaszczyk

Physical context: Study the evolution of a strongly coupled plasma system from various initial conditions until a hydrodynamic description becomes accurate... Method: Describe the time dependent evolving strongly coupled plasma system through a dual 5D geometry — given e.g. by ds2 = gµν(xρ, z)dxµdxν + dz2 z2 ≡ g 5D

αβdxαdxβ

i) use Einstein’s equations for the time evolution Rαβ − 1 2g 5D

αβR − 6 g 5D αβ = 0

ii) read off Tµν(xρ) from the numerical metric gµν(xρ, z) gµν(xρ, z) = ηµν + z4g (4)

µν (xρ) + . . .

Tµν(xρ) = N2

c

2π2 · g (4)

µν (xρ)

6 / 24

slide-40
SLIDE 40
  • I. Outer boundary conditions (in the bulk)

Various initial geometries correspond intuitively (at weak coupling) to preparing the initial plasma system with various momentum distributions

  • f gluons...

Question: What kind of initial conditions to consider?

◮ What kind of initial geometries on the initial slice are acceptable? ◮ One possibility would be to consider only geometries regular until

the ‘center of AdS’...

◮ However we will want to include also geometries whose curvature

blows up as we go into the bulk...

◮ These may be physically acceptable initial conditions if the

singularity is cloaked by an event horizon. How to cut-off the numerical grid??

7 / 24

slide-41
SLIDE 41
  • I. Outer boundary conditions (in the bulk)

Various initial geometries correspond intuitively (at weak coupling) to preparing the initial plasma system with various momentum distributions

  • f gluons...

Question: What kind of initial conditions to consider?

◮ What kind of initial geometries on the initial slice are acceptable? ◮ One possibility would be to consider only geometries regular until

the ‘center of AdS’...

◮ However we will want to include also geometries whose curvature

blows up as we go into the bulk...

◮ These may be physically acceptable initial conditions if the

singularity is cloaked by an event horizon. How to cut-off the numerical grid??

7 / 24

slide-42
SLIDE 42
  • I. Outer boundary conditions (in the bulk)

Various initial geometries correspond intuitively (at weak coupling) to preparing the initial plasma system with various momentum distributions

  • f gluons...

Question: What kind of initial conditions to consider?

◮ What kind of initial geometries on the initial slice are acceptable? ◮ One possibility would be to consider only geometries regular until

the ‘center of AdS’...

◮ However we will want to include also geometries whose curvature

blows up as we go into the bulk...

◮ These may be physically acceptable initial conditions if the

singularity is cloaked by an event horizon. How to cut-off the numerical grid??

7 / 24

slide-43
SLIDE 43
  • I. Outer boundary conditions (in the bulk)

Various initial geometries correspond intuitively (at weak coupling) to preparing the initial plasma system with various momentum distributions

  • f gluons...

Question: What kind of initial conditions to consider?

◮ What kind of initial geometries on the initial slice are acceptable? ◮ One possibility would be to consider only geometries regular until

the ‘center of AdS’...

◮ However we will want to include also geometries whose curvature

blows up as we go into the bulk...

◮ These may be physically acceptable initial conditions if the

singularity is cloaked by an event horizon. How to cut-off the numerical grid??

7 / 24

slide-44
SLIDE 44
  • I. Outer boundary conditions (in the bulk)

Various initial geometries correspond intuitively (at weak coupling) to preparing the initial plasma system with various momentum distributions

  • f gluons...

Question: What kind of initial conditions to consider?

◮ What kind of initial geometries on the initial slice are acceptable? ◮ One possibility would be to consider only geometries regular until

the ‘center of AdS’...

◮ However we will want to include also geometries whose curvature

blows up as we go into the bulk...

◮ These may be physically acceptable initial conditions if the

singularity is cloaked by an event horizon. How to cut-off the numerical grid??

7 / 24

slide-45
SLIDE 45
  • I. Outer boundary conditions (in the bulk)

Various initial geometries correspond intuitively (at weak coupling) to preparing the initial plasma system with various momentum distributions

  • f gluons...

Question: What kind of initial conditions to consider?

◮ What kind of initial geometries on the initial slice are acceptable? ◮ One possibility would be to consider only geometries regular until

the ‘center of AdS’...

◮ However we will want to include also geometries whose curvature

blows up as we go into the bulk...

◮ These may be physically acceptable initial conditions if the

singularity is cloaked by an event horizon. How to cut-off the numerical grid??

7 / 24

slide-46
SLIDE 46
  • I. Outer boundary conditions (in the bulk)

Various initial geometries correspond intuitively (at weak coupling) to preparing the initial plasma system with various momentum distributions

  • f gluons...

Question: What kind of initial conditions to consider?

◮ What kind of initial geometries on the initial slice are acceptable? ◮ One possibility would be to consider only geometries regular until

the ‘center of AdS’...

◮ However we will want to include also geometries whose curvature

blows up as we go into the bulk...

◮ These may be physically acceptable initial conditions if the

singularity is cloaked by an event horizon. How to cut-off the numerical grid??

7 / 24

slide-47
SLIDE 47
  • I. Outer boundary conditions (in the bulk)

Various initial geometries correspond intuitively (at weak coupling) to preparing the initial plasma system with various momentum distributions

  • f gluons...

Question: What kind of initial conditions to consider?

◮ What kind of initial geometries on the initial slice are acceptable? ◮ One possibility would be to consider only geometries regular until

the ‘center of AdS’...

◮ However we will want to include also geometries whose curvature

blows up as we go into the bulk...

◮ These may be physically acceptable initial conditions if the

singularity is cloaked by an event horizon. How to cut-off the numerical grid??

7 / 24

slide-48
SLIDE 48
  • I. Outer boundary conditions (in the bulk)

Standard answer: Locate an apparent horizon, then use whatever techniques are used to excise the rest of spacetime... However we encounter a problem due to our ‘kinematics’... Boost-invariant flow

Bjorken ’83

Assume a flow that is invariant under longitudinal boosts and does not depend on the transverse coordinates. At τ = 0, the initial hypersurface intersected with the boundary is light-like

8 / 24

slide-49
SLIDE 49
  • I. Outer boundary conditions (in the bulk)

Standard answer: Locate an apparent horizon, then use whatever techniques are used to excise the rest of spacetime... However we encounter a problem due to our ‘kinematics’... Boost-invariant flow

Bjorken ’83

Assume a flow that is invariant under longitudinal boosts and does not depend on the transverse coordinates. At τ = 0, the initial hypersurface intersected with the boundary is light-like

8 / 24

slide-50
SLIDE 50
  • I. Outer boundary conditions (in the bulk)

Standard answer: Locate an apparent horizon, then use whatever techniques are used to excise the rest of spacetime... However we encounter a problem due to our ‘kinematics’... Boost-invariant flow

Bjorken ’83

Assume a flow that is invariant under longitudinal boosts and does not depend on the transverse coordinates. At τ = 0, the initial hypersurface intersected with the boundary is light-like

8 / 24

slide-51
SLIDE 51
  • I. Outer boundary conditions (in the bulk)

Standard answer: Locate an apparent horizon, then use whatever techniques are used to excise the rest of spacetime... However we encounter a problem due to our ‘kinematics’... Boost-invariant flow

Bjorken ’83

Assume a flow that is invariant under longitudinal boosts and does not depend on the transverse coordinates. At τ = 0, the initial hypersurface intersected with the boundary is light-like

8 / 24

slide-52
SLIDE 52
  • I. Outer boundary conditions (in the bulk)

Standard answer: Locate an apparent horizon, then use whatever techniques are used to excise the rest of spacetime... However we encounter a problem due to our ‘kinematics’... Boost-invariant flow

Bjorken ’83

Assume a flow that is invariant under longitudinal boosts and does not depend on the transverse coordinates. At τ = 0, the initial hypersurface intersected with the boundary is light-like

8 / 24

slide-53
SLIDE 53
  • I. Outer boundary conditions (in the bulk)

Standard answer: Locate an apparent horizon, then use whatever techniques are used to excise the rest of spacetime... However we encounter a problem due to our ‘kinematics’... Boost-invariant flow

Bjorken ’83

Assume a flow that is invariant under longitudinal boosts and does not depend on the transverse coordinates. At τ = 0, the initial hypersurface intersected with the boundary is light-like

8 / 24

slide-54
SLIDE 54
  • I. Outer boundary conditions (in the bulk)

Standard answer: Locate an apparent horizon, then use whatever techniques are used to excise the rest of spacetime... However we encounter a problem due to our ‘kinematics’... Boost-invariant flow

Bjorken ’83

Assume a flow that is invariant under longitudinal boosts and does not depend on the transverse coordinates. At τ = 0, the initial hypersurface intersected with the boundary is light-like

8 / 24

slide-55
SLIDE 55
  • I. Outer boundary conditions (in the bulk)

Standard answer: Locate an apparent horizon, then use whatever techniques are used to excise the rest of spacetime... However we encounter a problem due to our ‘kinematics’... Boost-invariant flow

Bjorken ’83

Assume a flow that is invariant under longitudinal boosts and does not depend on the transverse coordinates. At τ = 0, the initial hypersurface intersected with the boundary is light-like

8 / 24

slide-56
SLIDE 56
  • I. Outer boundary conditions (in the bulk)

◮ We chose our initial hypersurface to also have null directions

in the bulk at τ = 0

◮ Due to this geometry, it turns out that the condition for apparent

horizon is never satisfied...

◮ What kind of boundary conditions to impose at the edge?? ◮ We cannot use any radiative outgoing conditions as the curvature at

the outer edge may be quite large..

9 / 24

slide-57
SLIDE 57
  • I. Outer boundary conditions (in the bulk)

◮ We chose our initial hypersurface to also have null directions

in the bulk at τ = 0

◮ Due to this geometry, it turns out that the condition for apparent

horizon is never satisfied...

◮ What kind of boundary conditions to impose at the edge?? ◮ We cannot use any radiative outgoing conditions as the curvature at

the outer edge may be quite large..

9 / 24

slide-58
SLIDE 58
  • I. Outer boundary conditions (in the bulk)

◮ We chose our initial hypersurface to also have null directions

in the bulk at τ = 0

◮ Due to this geometry, it turns out that the condition for apparent

horizon is never satisfied...

◮ What kind of boundary conditions to impose at the edge?? ◮ We cannot use any radiative outgoing conditions as the curvature at

the outer edge may be quite large..

9 / 24

slide-59
SLIDE 59
  • I. Outer boundary conditions (in the bulk)

◮ We chose our initial hypersurface to also have null directions

in the bulk at τ = 0

◮ Due to this geometry, it turns out that the condition for apparent

horizon is never satisfied...

◮ What kind of boundary conditions to impose at the edge?? ◮ We cannot use any radiative outgoing conditions as the curvature at

the outer edge may be quite large..

9 / 24

slide-60
SLIDE 60
  • I. Outer boundary conditions (in the bulk)

◮ We chose our initial hypersurface to also have null directions

in the bulk at τ = 0

◮ Due to this geometry, it turns out that the condition for apparent

horizon is never satisfied...

◮ What kind of boundary conditions to impose at the edge?? ◮ We cannot use any radiative outgoing conditions as the curvature at

the outer edge may be quite large..

9 / 24

slide-61
SLIDE 61
  • I. Outer boundary conditions (in the bulk)

◮ We chose our initial hypersurface to also have null directions

in the bulk at τ = 0

◮ Due to this geometry, it turns out that the condition for apparent

horizon is never satisfied...

◮ What kind of boundary conditions to impose at the edge?? ◮ We cannot use any radiative outgoing conditions as the curvature at

the outer edge may be quite large..

9 / 24

slide-62
SLIDE 62
  • I. Outer boundary conditions (in the bulk)

◮ We chose our initial hypersurface to also have null directions

in the bulk at τ = 0

◮ Due to this geometry, it turns out that the condition for apparent

horizon is never satisfied...

◮ What kind of boundary conditions to impose at the edge?? ◮ We cannot use any radiative outgoing conditions as the curvature at

the outer edge may be quite large..

9 / 24

slide-63
SLIDE 63
  • I. Outer boundary conditions (in the bulk)

◮ We use the ADM freedom of foliation to ensure that all

hypersurfaces end on a single spacetime point in the bulk (more precisely a light-cone×R2) — this ensures that we will control the boundary conditions even though they may be in a strongly curved part of the spacetime

◮ This also ensures that no information flows from outside our region

  • f integration...

◮ It is crucial to optimally tune the cut-off u0 in the bulk...

10 / 24

slide-64
SLIDE 64
  • I. Outer boundary conditions (in the bulk)

◮ We use the ADM freedom of foliation to ensure that all

hypersurfaces end on a single spacetime point in the bulk (more precisely a light-cone×R2) — this ensures that we will control the boundary conditions even though they may be in a strongly curved part of the spacetime

◮ This also ensures that no information flows from outside our region

  • f integration...

◮ It is crucial to optimally tune the cut-off u0 in the bulk...

10 / 24

slide-65
SLIDE 65
  • I. Outer boundary conditions (in the bulk)

◮ We use the ADM freedom of foliation to ensure that all

hypersurfaces end on a single spacetime point in the bulk (more precisely a light-cone×R2) — this ensures that we will control the boundary conditions even though they may be in a strongly curved part of the spacetime

◮ This also ensures that no information flows from outside our region

  • f integration...

◮ It is crucial to optimally tune the cut-off u0 in the bulk...

10 / 24

slide-66
SLIDE 66
  • I. Outer boundary conditions (in the bulk)

◮ We use the ADM freedom of foliation to ensure that all

hypersurfaces end on a single spacetime point in the bulk (more precisely a light-cone×R2) — this ensures that we will control the boundary conditions even though they may be in a strongly curved part of the spacetime

◮ This also ensures that no information flows from outside our region

  • f integration...

◮ It is crucial to optimally tune the cut-off u0 in the bulk...

10 / 24

slide-67
SLIDE 67
  • I. Outer boundary conditions (in the bulk)

◮ We use the ADM freedom of foliation to ensure that all

hypersurfaces end on a single spacetime point in the bulk (more precisely a light-cone×R2) — this ensures that we will control the boundary conditions even though they may be in a strongly curved part of the spacetime

◮ This also ensures that no information flows from outside our region

  • f integration...

◮ It is crucial to optimally tune the cut-off u0 in the bulk...

10 / 24

slide-68
SLIDE 68
  • I. Outer boundary conditions (in the bulk)

◮ We use the ADM freedom of foliation to ensure that all

hypersurfaces end on a single spacetime point in the bulk (more precisely a light-cone×R2) — this ensures that we will control the boundary conditions even though they may be in a strongly curved part of the spacetime

◮ This also ensures that no information flows from outside our region

  • f integration...

◮ It is crucial to optimally tune the cut-off u0 in the bulk...

10 / 24

slide-69
SLIDE 69
  • I. Outer boundary conditions (in the bulk)

◮ Depending on the relation of u0 to the event horizon we can get

quite different behaviours of the numerical simulation

◮ In order to extend the simulation to large values of τ neccessary for

  • bserving the transition to hydrodynamics we need to tune u0 to be

close to the event horizon.

◮ Fortunately, this is quite simple in practice...

11 / 24

slide-70
SLIDE 70
  • I. Outer boundary conditions (in the bulk)

◮ Depending on the relation of u0 to the event horizon we can get

quite different behaviours of the numerical simulation

◮ In order to extend the simulation to large values of τ neccessary for

  • bserving the transition to hydrodynamics we need to tune u0 to be

close to the event horizon.

◮ Fortunately, this is quite simple in practice...

11 / 24

slide-71
SLIDE 71
  • I. Outer boundary conditions (in the bulk)

◮ Depending on the relation of u0 to the event horizon we can get

quite different behaviours of the numerical simulation

◮ In order to extend the simulation to large values of τ neccessary for

  • bserving the transition to hydrodynamics we need to tune u0 to be

close to the event horizon.

◮ Fortunately, this is quite simple in practice...

11 / 24

slide-72
SLIDE 72
  • I. Outer boundary conditions (in the bulk)

◮ Depending on the relation of u0 to the event horizon we can get

quite different behaviours of the numerical simulation

◮ In order to extend the simulation to large values of τ neccessary for

  • bserving the transition to hydrodynamics we need to tune u0 to be

close to the event horizon.

◮ Fortunately, this is quite simple in practice...

11 / 24

slide-73
SLIDE 73
  • I. Outer boundary conditions (in the bulk)

black line – dynamical horizon, arrows – null geodesics, colors represent curvature

12 / 24

slide-74
SLIDE 74
  • I. Outer boundary conditions (in the bulk)

◮ Technically we freeze evolution at the outer boundary by

forcing the ADM lapse function to vanish there...

◮ We perform an initial exploratory simulation to locate the

approximate position of the event horizon

◮ Then we adjust the outer boundary to the intersection of the event

horizon with the initial hypersurface

13 / 24

slide-75
SLIDE 75
  • I. Outer boundary conditions (in the bulk)

◮ Technically we freeze evolution at the outer boundary by

forcing the ADM lapse function to vanish there...

◮ We perform an initial exploratory simulation to locate the

approximate position of the event horizon

◮ Then we adjust the outer boundary to the intersection of the event

horizon with the initial hypersurface

13 / 24

slide-76
SLIDE 76
  • I. Outer boundary conditions (in the bulk)

◮ Technically we freeze evolution at the outer boundary by

forcing the ADM lapse function to vanish there...

◮ We perform an initial exploratory simulation to locate the

approximate position of the event horizon

◮ Then we adjust the outer boundary to the intersection of the event

horizon with the initial hypersurface

13 / 24

slide-77
SLIDE 77
  • I. Outer boundary conditions (in the bulk)

◮ Technically we freeze evolution at the outer boundary by

forcing the ADM lapse function to vanish there...

◮ We perform an initial exploratory simulation to locate the

approximate position of the event horizon

◮ Then we adjust the outer boundary to the intersection of the event

horizon with the initial hypersurface

13 / 24

slide-78
SLIDE 78
  • II. Subtleties with ADM boundary conditions at the AdS boundary
  • M. Heller, RJ, P. Witaszczyk

Physical condition in the AdS/CFT context: The asymptotic form of the metric at the AdS boundary should be Minkowski.. i.e. at the boundary (z ∼ 0) it should be possible to write the metric as ds2 = 1 z2

  • gµνdxµdxν + dz2

with gµν = ηµν + z4g (4)

µν + . . .

14 / 24

slide-79
SLIDE 79
  • II. Subtleties with ADM boundary conditions at the AdS boundary
  • M. Heller, RJ, P. Witaszczyk

Physical condition in the AdS/CFT context: The asymptotic form of the metric at the AdS boundary should be Minkowski.. i.e. at the boundary (z ∼ 0) it should be possible to write the metric as ds2 = 1 z2

  • gµνdxµdxν + dz2

with gµν = ηµν + z4g (4)

µν + . . .

14 / 24

slide-80
SLIDE 80
  • II. Subtleties with ADM boundary conditions at the AdS boundary
  • M. Heller, RJ, P. Witaszczyk

Physical condition in the AdS/CFT context: The asymptotic form of the metric at the AdS boundary should be Minkowski.. i.e. at the boundary (z ∼ 0) it should be possible to write the metric as ds2 = 1 z2

  • gµνdxµdxν + dz2

with gµν = ηµν + z4g (4)

µν + . . .

14 / 24

slide-81
SLIDE 81
  • II. Subtleties with ADM boundary conditions at the AdS boundary

◮ We used an ADM form of the metric (u ∼ z2)

ds2 = −a2(u) α2(t, u)dt2 + t2a2(u)b2(t, u)dy 2 + c2(t, u)dx2

u +d2(t, u)du2 4u2

◮ b(t, u), c(t, u), d(t, u) are the dynamical metric coefficients. u = 0

is the boundary, u > 0 is the bulk.

◮ Empty AdS5 is given by b = c = d = 1 ◮ However Dirichlet conditions b = c = d = 1 are usually incorrect

15 / 24

slide-82
SLIDE 82
  • II. Subtleties with ADM boundary conditions at the AdS boundary

◮ We used an ADM form of the metric (u ∼ z2)

ds2 = −a2(u) α2(t, u)dt2 + t2a2(u)b2(t, u)dy 2 + c2(t, u)dx2

u +d2(t, u)du2 4u2

◮ b(t, u), c(t, u), d(t, u) are the dynamical metric coefficients. u = 0

is the boundary, u > 0 is the bulk.

◮ Empty AdS5 is given by b = c = d = 1 ◮ However Dirichlet conditions b = c = d = 1 are usually incorrect

15 / 24

slide-83
SLIDE 83
  • II. Subtleties with ADM boundary conditions at the AdS boundary

◮ We used an ADM form of the metric (u ∼ z2)

ds2 = −a2(u) α2(t, u)dt2 + t2a2(u)b2(t, u)dy 2 + c2(t, u)dx2

u +d2(t, u)du2 4u2

◮ b(t, u), c(t, u), d(t, u) are the dynamical metric coefficients. u = 0

is the boundary, u > 0 is the bulk.

◮ Empty AdS5 is given by b = c = d = 1 ◮ However Dirichlet conditions b = c = d = 1 are usually incorrect

15 / 24

slide-84
SLIDE 84
  • II. Subtleties with ADM boundary conditions at the AdS boundary

◮ We used an ADM form of the metric (u ∼ z2)

ds2 = −a2(u) α2(t, u)dt2 + t2a2(u)b2(t, u)dy 2 + c2(t, u)dx2

u +d2(t, u)du2 4u2

◮ b(t, u), c(t, u), d(t, u) are the dynamical metric coefficients. u = 0

is the boundary, u > 0 is the bulk.

◮ Empty AdS5 is given by b = c = d = 1 ◮ However Dirichlet conditions b = c = d = 1 are usually incorrect

15 / 24

slide-85
SLIDE 85
  • II. Subtleties with ADM boundary conditions at the AdS boundary

◮ We used an ADM form of the metric (u ∼ z2)

ds2 = −a2(u) α2(t, u)dt2 + t2a2(u)b2(t, u)dy 2 + c2(t, u)dx2

u +d2(t, u)du2 4u2

◮ b(t, u), c(t, u), d(t, u) are the dynamical metric coefficients. u = 0

is the boundary, u > 0 is the bulk.

◮ Empty AdS5 is given by b = c = d = 1 ◮ However Dirichlet conditions b = c = d = 1 are usually incorrect

15 / 24

slide-86
SLIDE 86
  • II. Subtleties with ADM boundary conditions at the AdS boundary

◮ One can make a diffeomorphism from the Fefferman-Graham

Minkowski form τ = f (t) + u f1(t) + .. z = g0(t)u

1 2 + g1(t)u 3 2 + . . .

and obtain an ADM metric with nontrivial boundary values of b(t, u), c(t, u), d(t, u)

◮ One has to work out the conditions under which the boundary metric

is related to Minkowski through such a boundary diffeomorphism

◮ This leads to quite nontrivial constraints in the ADM formulation...

16 / 24

slide-87
SLIDE 87
  • II. Subtleties with ADM boundary conditions at the AdS boundary

◮ One can make a diffeomorphism from the Fefferman-Graham

Minkowski form τ = f (t) + u f1(t) + .. z = g0(t)u

1 2 + g1(t)u 3 2 + . . .

and obtain an ADM metric with nontrivial boundary values of b(t, u), c(t, u), d(t, u)

◮ One has to work out the conditions under which the boundary metric

is related to Minkowski through such a boundary diffeomorphism

◮ This leads to quite nontrivial constraints in the ADM formulation...

16 / 24

slide-88
SLIDE 88
  • II. Subtleties with ADM boundary conditions at the AdS boundary

◮ One can make a diffeomorphism from the Fefferman-Graham

Minkowski form τ = f (t) + u f1(t) + .. z = g0(t)u

1 2 + g1(t)u 3 2 + . . .

and obtain an ADM metric with nontrivial boundary values of b(t, u), c(t, u), d(t, u)

◮ One has to work out the conditions under which the boundary metric

is related to Minkowski through such a boundary diffeomorphism

◮ This leads to quite nontrivial constraints in the ADM formulation...

16 / 24

slide-89
SLIDE 89
  • II. Subtleties with ADM boundary conditions at the AdS boundary

◮ One can make a diffeomorphism from the Fefferman-Graham

Minkowski form τ = f (t) + u f1(t) + .. z = g0(t)u

1 2 + g1(t)u 3 2 + . . .

and obtain an ADM metric with nontrivial boundary values of b(t, u), c(t, u), d(t, u)

◮ One has to work out the conditions under which the boundary metric

is related to Minkowski through such a boundary diffeomorphism

◮ This leads to quite nontrivial constraints in the ADM formulation...

16 / 24

slide-90
SLIDE 90
  • II. Subtleties with ADM boundary conditions at the AdS boundary

◮ One can make a diffeomorphism from the Fefferman-Graham

Minkowski form τ = f (t) + u f1(t) + .. z = g0(t)u

1 2 + g1(t)u 3 2 + . . .

and obtain an ADM metric with nontrivial boundary values of b(t, u), c(t, u), d(t, u)

◮ One has to work out the conditions under which the boundary metric

is related to Minkowski through such a boundary diffeomorphism

◮ This leads to quite nontrivial constraints in the ADM formulation...

16 / 24

slide-91
SLIDE 91
  • III. Dirac δ-like boundary conditions

RJ, J.Jankowski, P. Witkowski, work in progress

Recall

◮ Within the AdS/CFT correspondence (gravity and matter) fields in

the bulk – e.g. a scalar field φ(xµ, z) – correspond to some particular local operators on the gauge theory side – O (xµ)

◮ Suppose that the scalar field φ(xµ, z) has the near-boundary

expansion φ(xµ, z) ∼ z φ0(xµ)

  • non−normalizable

+ z2 φ1(xµ)

  • normalizable

+ . . .

◮ Then φ0(xµ) is a source for deforming the field theory action

e−S+

  • dnx φ0(xµ) O(xµ)

while φ1(xµ) is the corresponding expectation value O (xµ) = φ1(xµ)

17 / 24

slide-92
SLIDE 92
  • III. Dirac δ-like boundary conditions

RJ, J.Jankowski, P. Witkowski, work in progress

Recall

◮ Within the AdS/CFT correspondence (gravity and matter) fields in

the bulk – e.g. a scalar field φ(xµ, z) – correspond to some particular local operators on the gauge theory side – O (xµ)

◮ Suppose that the scalar field φ(xµ, z) has the near-boundary

expansion φ(xµ, z) ∼ z φ0(xµ)

  • non−normalizable

+ z2 φ1(xµ)

  • normalizable

+ . . .

◮ Then φ0(xµ) is a source for deforming the field theory action

e−S+

  • dnx φ0(xµ) O(xµ)

while φ1(xµ) is the corresponding expectation value O (xµ) = φ1(xµ)

17 / 24

slide-93
SLIDE 93
  • III. Dirac δ-like boundary conditions

RJ, J.Jankowski, P. Witkowski, work in progress

Recall

◮ Within the AdS/CFT correspondence (gravity and matter) fields in

the bulk – e.g. a scalar field φ(xµ, z) – correspond to some particular local operators on the gauge theory side – O (xµ)

◮ Suppose that the scalar field φ(xµ, z) has the near-boundary

expansion φ(xµ, z) ∼ z φ0(xµ)

  • non−normalizable

+ z2 φ1(xµ)

  • normalizable

+ . . .

◮ Then φ0(xµ) is a source for deforming the field theory action

e−S+

  • dnx φ0(xµ) O(xµ)

while φ1(xµ) is the corresponding expectation value O (xµ) = φ1(xµ)

17 / 24

slide-94
SLIDE 94
  • III. Dirac δ-like boundary conditions

RJ, J.Jankowski, P. Witkowski, work in progress

Recall

◮ Within the AdS/CFT correspondence (gravity and matter) fields in

the bulk – e.g. a scalar field φ(xµ, z) – correspond to some particular local operators on the gauge theory side – O (xµ)

◮ Suppose that the scalar field φ(xµ, z) has the near-boundary

expansion φ(xµ, z) ∼ z φ0(xµ)

  • non−normalizable

+ z2 φ1(xµ)

  • normalizable

+ . . .

◮ Then φ0(xµ) is a source for deforming the field theory action

e−S+

  • dnx φ0(xµ) O(xµ)

while φ1(xµ) is the corresponding expectation value O (xµ) = φ1(xµ)

17 / 24

slide-95
SLIDE 95
  • III. Dirac δ-like boundary conditions

RJ, J.Jankowski, P. Witkowski, work in progress

Recall

◮ Within the AdS/CFT correspondence (gravity and matter) fields in

the bulk – e.g. a scalar field φ(xµ, z) – correspond to some particular local operators on the gauge theory side – O (xµ)

◮ Suppose that the scalar field φ(xµ, z) has the near-boundary

expansion φ(xµ, z) ∼ z φ0(xµ)

  • non−normalizable

+ z2 φ1(xµ)

  • normalizable

+ . . .

◮ Then φ0(xµ) is a source for deforming the field theory action

e−S+

  • dnx φ0(xµ) O(xµ)

while φ1(xµ) is the corresponding expectation value O (xµ) = φ1(xµ)

17 / 24

slide-96
SLIDE 96
  • III. Dirac δ-like boundary conditions

RJ, J.Jankowski, P. Witkowski, work in progress

Recall

◮ Within the AdS/CFT correspondence (gravity and matter) fields in

the bulk – e.g. a scalar field φ(xµ, z) – correspond to some particular local operators on the gauge theory side – O (xµ)

◮ Suppose that the scalar field φ(xµ, z) has the near-boundary

expansion φ(xµ, z) ∼ z φ0(xµ)

  • non−normalizable

+ z2 φ1(xµ)

  • normalizable

+ . . .

◮ Then φ0(xµ) is a source for deforming the field theory action

e−S+

  • dnx φ0(xµ) O(xµ)

while φ1(xµ) is the corresponding expectation value O (xµ) = φ1(xµ)

17 / 24

slide-97
SLIDE 97
  • III. Dirac δ-like boundary conditions

Question: What happens for local point-like sources like φ0(x) = η δ2(x)

  • r line-like sources

φ0(x, y) = η δ(x) Motivation:

◮ Horowitz, Santos, Tong use cos(kx) source to mimick a lattice... ◮ Try to construct a lattice from n δ(x − na)... ◮ Look at single defects and their properties...

18 / 24

slide-98
SLIDE 98
  • III. Dirac δ-like boundary conditions

Question: What happens for local point-like sources like φ0(x) = η δ2(x)

  • r line-like sources

φ0(x, y) = η δ(x) Motivation:

◮ Horowitz, Santos, Tong use cos(kx) source to mimick a lattice... ◮ Try to construct a lattice from n δ(x − na)... ◮ Look at single defects and their properties...

18 / 24

slide-99
SLIDE 99
  • III. Dirac δ-like boundary conditions

Question: What happens for local point-like sources like φ0(x) = η δ2(x)

  • r line-like sources

φ0(x, y) = η δ(x) Motivation:

◮ Horowitz, Santos, Tong use cos(kx) source to mimick a lattice... ◮ Try to construct a lattice from n δ(x − na)... ◮ Look at single defects and their properties...

18 / 24

slide-100
SLIDE 100
  • III. Dirac δ-like boundary conditions

Question: What happens for local point-like sources like φ0(x) = η δ2(x)

  • r line-like sources

φ0(x, y) = η δ(x) Motivation:

◮ Horowitz, Santos, Tong use cos(kx) source to mimick a lattice... ◮ Try to construct a lattice from n δ(x − na)... ◮ Look at single defects and their properties...

18 / 24

slide-101
SLIDE 101
  • III. Dirac δ-like boundary conditions

Question: What happens for local point-like sources like φ0(x) = η δ2(x)

  • r line-like sources

φ0(x, y) = η δ(x) Motivation:

◮ Horowitz, Santos, Tong use cos(kx) source to mimick a lattice... ◮ Try to construct a lattice from n δ(x − na)... ◮ Look at single defects and their properties...

18 / 24

slide-102
SLIDE 102
  • III. Dirac δ-like boundary conditions

Question: What happens for local point-like sources like φ0(x) = η δ2(x)

  • r line-like sources

φ0(x, y) = η δ(x) Motivation:

◮ Horowitz, Santos, Tong use cos(kx) source to mimick a lattice... ◮ Try to construct a lattice from n δ(x − na)... ◮ Look at single defects and their properties...

18 / 24

slide-103
SLIDE 103
  • III. Dirac δ-like boundary conditions

Question: What happens for local point-like sources like φ0(x) = η δ2(x)

  • r line-like sources

φ0(x, y) = η δ(x) Motivation:

◮ Horowitz, Santos, Tong use cos(kx) source to mimick a lattice... ◮ Try to construct a lattice from n δ(x − na)... ◮ Look at single defects and their properties...

18 / 24

slide-104
SLIDE 104
  • III. Dirac δ-like boundary conditions

Problem: Develop techniques to numerically solve Einstein’s equations (with matter fields) with b.c. φ(xµ, z) → zδ(x) What is known for discontinuous boundary conditions

◮ θ(x) with m2 = 0: Janus solutions (analytical, 1D ODE)

Bak, Gutperle, Hirano + many subsequent investigations

◮ θ(x) with m2 = 0 at T = 0: Janus BH – numerical PDE and

analytical in 2+1 dimensions

Bak, Gutperle, RJ

◮ δ(x) with m2 = −2 and SUSY: analytical, scale invariant

d’Hoker, Estes, Gutperle, Krym

19 / 24

slide-105
SLIDE 105
  • III. Dirac δ-like boundary conditions

Problem: Develop techniques to numerically solve Einstein’s equations (with matter fields) with b.c. φ(xµ, z) → zδ(x) What is known for discontinuous boundary conditions

◮ θ(x) with m2 = 0: Janus solutions (analytical, 1D ODE)

Bak, Gutperle, Hirano + many subsequent investigations

◮ θ(x) with m2 = 0 at T = 0: Janus BH – numerical PDE and

analytical in 2+1 dimensions

Bak, Gutperle, RJ

◮ δ(x) with m2 = −2 and SUSY: analytical, scale invariant

d’Hoker, Estes, Gutperle, Krym

19 / 24

slide-106
SLIDE 106
  • III. Dirac δ-like boundary conditions

Problem: Develop techniques to numerically solve Einstein’s equations (with matter fields) with b.c. φ(xµ, z) → zδ(x) What is known for discontinuous boundary conditions

◮ θ(x) with m2 = 0: Janus solutions (analytical, 1D ODE)

Bak, Gutperle, Hirano + many subsequent investigations

◮ θ(x) with m2 = 0 at T = 0: Janus BH – numerical PDE and

analytical in 2+1 dimensions

Bak, Gutperle, RJ

◮ δ(x) with m2 = −2 and SUSY: analytical, scale invariant

d’Hoker, Estes, Gutperle, Krym

19 / 24

slide-107
SLIDE 107
  • III. Dirac δ-like boundary conditions

Problem: Develop techniques to numerically solve Einstein’s equations (with matter fields) with b.c. φ(xµ, z) → zδ(x) What is known for discontinuous boundary conditions

◮ θ(x) with m2 = 0: Janus solutions (analytical, 1D ODE)

Bak, Gutperle, Hirano + many subsequent investigations

◮ θ(x) with m2 = 0 at T = 0: Janus BH – numerical PDE and

analytical in 2+1 dimensions

Bak, Gutperle, RJ

◮ δ(x) with m2 = −2 and SUSY: analytical, scale invariant

d’Hoker, Estes, Gutperle, Krym

19 / 24

slide-108
SLIDE 108
  • III. Dirac δ-like boundary conditions

Problem: Develop techniques to numerically solve Einstein’s equations (with matter fields) with b.c. φ(xµ, z) → zδ(x) What is known for discontinuous boundary conditions

◮ θ(x) with m2 = 0: Janus solutions (analytical, 1D ODE)

Bak, Gutperle, Hirano + many subsequent investigations

◮ θ(x) with m2 = 0 at T = 0: Janus BH – numerical PDE and

analytical in 2+1 dimensions

Bak, Gutperle, RJ

◮ δ(x) with m2 = −2 and SUSY: analytical, scale invariant

d’Hoker, Estes, Gutperle, Krym

19 / 24

slide-109
SLIDE 109
  • III. Dirac δ-like boundary conditions

Problem: Develop techniques to numerically solve Einstein’s equations (with matter fields) with b.c. φ(xµ, z) → zδ(x) What is known for discontinuous boundary conditions

◮ θ(x) with m2 = 0: Janus solutions (analytical, 1D ODE)

Bak, Gutperle, Hirano + many subsequent investigations

◮ θ(x) with m2 = 0 at T = 0: Janus BH – numerical PDE and

analytical in 2+1 dimensions

Bak, Gutperle, RJ

◮ δ(x) with m2 = −2 and SUSY: analytical, scale invariant

d’Hoker, Estes, Gutperle, Krym

19 / 24

slide-110
SLIDE 110
  • III. Dirac δ-like boundary conditions

Linearized solutions

◮ It is easy to obtain analytically linearized solutions around empty

AdS4 e.g. φ0(x, z) = η π z2 x2 + z2 for a line defect

◮ Numerical generalization to finite temperature/chemical potential

(i.e. a background charged black hole solution) is fairly easy

◮ For the m2 = −2 field and a line defect, the linearized solution is

scale invariant! Idea: use tan α ≡ x

z for T = 0 backreacted solution?

20 / 24

slide-111
SLIDE 111
  • III. Dirac δ-like boundary conditions

Linearized solutions

◮ It is easy to obtain analytically linearized solutions around empty

AdS4 e.g. φ0(x, z) = η π z2 x2 + z2 for a line defect

◮ Numerical generalization to finite temperature/chemical potential

(i.e. a background charged black hole solution) is fairly easy

◮ For the m2 = −2 field and a line defect, the linearized solution is

scale invariant! Idea: use tan α ≡ x

z for T = 0 backreacted solution?

20 / 24

slide-112
SLIDE 112
  • III. Dirac δ-like boundary conditions

Linearized solutions

◮ It is easy to obtain analytically linearized solutions around empty

AdS4 e.g. φ0(x, z) = η π z2 x2 + z2 for a line defect

◮ Numerical generalization to finite temperature/chemical potential

(i.e. a background charged black hole solution) is fairly easy

◮ For the m2 = −2 field and a line defect, the linearized solution is

scale invariant! Idea: use tan α ≡ x

z for T = 0 backreacted solution?

20 / 24

slide-113
SLIDE 113
  • III. Dirac δ-like boundary conditions

Linearized solutions

◮ It is easy to obtain analytically linearized solutions around empty

AdS4 e.g. φ0(x, z) = η π z2 x2 + z2 for a line defect

◮ Numerical generalization to finite temperature/chemical potential

(i.e. a background charged black hole solution) is fairly easy

◮ For the m2 = −2 field and a line defect, the linearized solution is

scale invariant! Idea: use tan α ≡ x

z for T = 0 backreacted solution?

20 / 24

slide-114
SLIDE 114
  • III. Dirac δ-like boundary conditions

Linearized solutions

◮ It is easy to obtain analytically linearized solutions around empty

AdS4 e.g. φ0(x, z) = η π z2 x2 + z2 for a line defect

◮ Numerical generalization to finite temperature/chemical potential

(i.e. a background charged black hole solution) is fairly easy

◮ For the m2 = −2 field and a line defect, the linearized solution is

scale invariant! Idea: use tan α ≡ x

z for T = 0 backreacted solution?

20 / 24

slide-115
SLIDE 115
  • III. Dirac δ-like boundary conditions

Linearized solutions

◮ It is easy to obtain analytically linearized solutions around empty

AdS4 e.g. φ0(x, z) = η π z2 x2 + z2 for a line defect

◮ Numerical generalization to finite temperature/chemical potential

(i.e. a background charged black hole solution) is fairly easy

◮ For the m2 = −2 field and a line defect, the linearized solution is

scale invariant! Idea: use tan α ≡ x

z for T = 0 backreacted solution?

20 / 24

slide-116
SLIDE 116
  • III. Dirac δ-like boundary conditions

Backreacted solution at T = 0?

◮ Assume that the full solution will be a function of α ◮ The metric will have an AdS slicing

ds2 = 1 A2(α)

  • dα2 + dt2 + dy 2 + dr 2

r 2

  • φ = φ(α)

◮ The AdS boundaries on both sides of the defect are at α = ±α0

(α0 = π/2)

◮ We performed both a numerical and an analytical perturbative

solution...

◮ Problem:

The backreacted scalar field neccessarily has a nonzero source at AdS boundaries! η δ(x) + (η3 + ...) 1 |x| Conclusion: The original δ(x) source has a dynamically generated scale (logs !?!) — no reduction to an ODE!

21 / 24

slide-117
SLIDE 117
  • III. Dirac δ-like boundary conditions

Backreacted solution at T = 0?

◮ Assume that the full solution will be a function of α ◮ The metric will have an AdS slicing

ds2 = 1 A2(α)

  • dα2 + dt2 + dy 2 + dr 2

r 2

  • φ = φ(α)

◮ The AdS boundaries on both sides of the defect are at α = ±α0

(α0 = π/2)

◮ We performed both a numerical and an analytical perturbative

solution...

◮ Problem:

The backreacted scalar field neccessarily has a nonzero source at AdS boundaries! η δ(x) + (η3 + ...) 1 |x| Conclusion: The original δ(x) source has a dynamically generated scale (logs !?!) — no reduction to an ODE!

21 / 24

slide-118
SLIDE 118
  • III. Dirac δ-like boundary conditions

Backreacted solution at T = 0?

◮ Assume that the full solution will be a function of α ◮ The metric will have an AdS slicing

ds2 = 1 A2(α)

  • dα2 + dt2 + dy 2 + dr 2

r 2

  • φ = φ(α)

◮ The AdS boundaries on both sides of the defect are at α = ±α0

(α0 = π/2)

◮ We performed both a numerical and an analytical perturbative

solution...

◮ Problem:

The backreacted scalar field neccessarily has a nonzero source at AdS boundaries! η δ(x) + (η3 + ...) 1 |x| Conclusion: The original δ(x) source has a dynamically generated scale (logs !?!) — no reduction to an ODE!

21 / 24

slide-119
SLIDE 119
  • III. Dirac δ-like boundary conditions

Backreacted solution at T = 0?

◮ Assume that the full solution will be a function of α ◮ The metric will have an AdS slicing

ds2 = 1 A2(α)

  • dα2 + dt2 + dy 2 + dr 2

r 2

  • φ = φ(α)

◮ The AdS boundaries on both sides of the defect are at α = ±α0

(α0 = π/2)

◮ We performed both a numerical and an analytical perturbative

solution...

◮ Problem:

The backreacted scalar field neccessarily has a nonzero source at AdS boundaries! η δ(x) + (η3 + ...) 1 |x| Conclusion: The original δ(x) source has a dynamically generated scale (logs !?!) — no reduction to an ODE!

21 / 24

slide-120
SLIDE 120
  • III. Dirac δ-like boundary conditions

Backreacted solution at T = 0?

◮ Assume that the full solution will be a function of α ◮ The metric will have an AdS slicing

ds2 = 1 A2(α)

  • dα2 + dt2 + dy 2 + dr 2

r 2

  • φ = φ(α)

◮ The AdS boundaries on both sides of the defect are at α = ±α0

(α0 = π/2)

◮ We performed both a numerical and an analytical perturbative

solution...

◮ Problem:

The backreacted scalar field neccessarily has a nonzero source at AdS boundaries! η δ(x) + (η3 + ...) 1 |x| Conclusion: The original δ(x) source has a dynamically generated scale (logs !?!) — no reduction to an ODE!

21 / 24

slide-121
SLIDE 121
  • III. Dirac δ-like boundary conditions

Backreacted solution at T = 0?

◮ Assume that the full solution will be a function of α ◮ The metric will have an AdS slicing

ds2 = 1 A2(α)

  • dα2 + dt2 + dy 2 + dr 2

r 2

  • φ = φ(α)

◮ The AdS boundaries on both sides of the defect are at α = ±α0

(α0 = π/2)

◮ We performed both a numerical and an analytical perturbative

solution...

◮ Problem:

The backreacted scalar field neccessarily has a nonzero source at AdS boundaries! η δ(x) + (η3 + ...) 1 |x| Conclusion: The original δ(x) source has a dynamically generated scale (logs !?!) — no reduction to an ODE!

21 / 24

slide-122
SLIDE 122
  • III. Dirac δ-like boundary conditions

Backreacted solution at T = 0?

◮ Assume that the full solution will be a function of α ◮ The metric will have an AdS slicing

ds2 = 1 A2(α)

  • dα2 + dt2 + dy 2 + dr 2

r 2

  • φ = φ(α)

◮ The AdS boundaries on both sides of the defect are at α = ±α0

(α0 = π/2)

◮ We performed both a numerical and an analytical perturbative

solution...

◮ Problem:

The backreacted scalar field neccessarily has a nonzero source at AdS boundaries! η δ(x) + (η3 + ...) 1 |x| Conclusion: The original δ(x) source has a dynamically generated scale (logs !?!) — no reduction to an ODE!

21 / 24

slide-123
SLIDE 123
  • III. Dirac δ-like boundary conditions

Backreacted solution at T = 0?

◮ Assume that the full solution will be a function of α ◮ The metric will have an AdS slicing

ds2 = 1 A2(α)

  • dα2 + dt2 + dy 2 + dr 2

r 2

  • φ = φ(α)

◮ The AdS boundaries on both sides of the defect are at α = ±α0

(α0 = π/2)

◮ We performed both a numerical and an analytical perturbative

solution...

◮ Problem:

The backreacted scalar field neccessarily has a nonzero source at AdS boundaries! η δ(x) + (η3 + ...) 1 |x| Conclusion: The original δ(x) source has a dynamically generated scale (logs !?!) — no reduction to an ODE!

21 / 24

slide-124
SLIDE 124
  • III. Dirac δ-like boundary conditions

Backreacted solution at T = 0?

◮ Assume that the full solution will be a function of α ◮ The metric will have an AdS slicing

ds2 = 1 A2(α)

  • dα2 + dt2 + dy 2 + dr 2

r 2

  • φ = φ(α)

◮ The AdS boundaries on both sides of the defect are at α = ±α0

(α0 = π/2)

◮ We performed both a numerical and an analytical perturbative

solution...

◮ Problem:

The backreacted scalar field neccessarily has a nonzero source at AdS boundaries! η δ(x) + (η3 + ...) 1 |x| Conclusion: The original δ(x) source has a dynamically generated scale (logs !?!) — no reduction to an ODE!

21 / 24

slide-125
SLIDE 125
  • III. Dirac δ-like boundary conditions

◮ Numerically construct first an

approximation of the Dirac-δ lattice at T = 0

◮ This can already be used for

studying various physical questions...

◮ Numerical problem — very

large gradients!!

◮ Structure of the linearized

scalar field for Dirac-δ lattice

◮ We use this information to

modify the numerical grid

◮ We can get insight about the

Dirac-δ solution..

22 / 24

slide-126
SLIDE 126
  • III. Dirac δ-like boundary conditions

◮ Numerically construct first an

approximation of the Dirac-δ lattice at T = 0

◮ This can already be used for

studying various physical questions...

◮ Numerical problem — very

large gradients!!

◮ Structure of the linearized

scalar field for Dirac-δ lattice

◮ We use this information to

modify the numerical grid

◮ We can get insight about the

Dirac-δ solution..

22 / 24

slide-127
SLIDE 127
  • III. Dirac δ-like boundary conditions

◮ Numerically construct first an

approximation of the Dirac-δ lattice at T = 0

◮ This can already be used for

studying various physical questions...

◮ Numerical problem — very

large gradients!!

◮ Structure of the linearized

scalar field for Dirac-δ lattice

◮ We use this information to

modify the numerical grid

◮ We can get insight about the

Dirac-δ solution..

22 / 24

slide-128
SLIDE 128
  • III. Dirac δ-like boundary conditions

◮ Numerically construct first an

approximation of the Dirac-δ lattice at T = 0

◮ This can already be used for

studying various physical questions...

◮ Numerical problem — very

large gradients!!

◮ Structure of the linearized

scalar field for Dirac-δ lattice

◮ We use this information to

modify the numerical grid

◮ We can get insight about the

Dirac-δ solution..

22 / 24

slide-129
SLIDE 129
  • III. Dirac δ-like boundary conditions

◮ Numerically construct first an

approximation of the Dirac-δ lattice at T = 0

◮ This can already be used for

studying various physical questions...

◮ Numerical problem — very

large gradients!!

◮ Structure of the linearized

scalar field for Dirac-δ lattice

◮ We use this information to

modify the numerical grid

◮ We can get insight about the

Dirac-δ solution..

22 / 24

slide-130
SLIDE 130
  • III. Dirac δ-like boundary conditions

◮ Numerically construct first an

approximation of the Dirac-δ lattice at T = 0

◮ This can already be used for

studying various physical questions...

◮ Numerical problem — very

large gradients!!

◮ Structure of the linearized

scalar field for Dirac-δ lattice

◮ We use this information to

modify the numerical grid

◮ We can get insight about the

Dirac-δ solution..

22 / 24

slide-131
SLIDE 131
  • III. Dirac δ-like boundary conditions

◮ Numerically construct first an

approximation of the Dirac-δ lattice at T = 0

◮ This can already be used for

studying various physical questions...

◮ Numerical problem — very

large gradients!!

◮ Structure of the linearized

scalar field for Dirac-δ lattice

◮ We use this information to

modify the numerical grid

◮ We can get insight about the

Dirac-δ solution..

22 / 24

slide-132
SLIDE 132
  • III. Dirac δ-like boundary conditions

◮ Numerically construct first an

approximation of the Dirac-δ lattice at T = 0

◮ This can already be used for

studying various physical questions...

◮ Numerical problem — very

large gradients!!

◮ Structure of the linearized

scalar field for Dirac-δ lattice

◮ We use this information to

modify the numerical grid

◮ We can get insight about the

Dirac-δ solution..

22 / 24

slide-133
SLIDE 133
  • III. Dirac δ-like boundary conditions

◮ Numerically construct first an

approximation of the Dirac-δ lattice at T = 0

◮ This can already be used for

studying various physical questions...

◮ Numerical problem — very

large gradients!!

◮ Structure of the linearized

scalar field for Dirac-δ lattice

◮ We use this information to

modify the numerical grid

◮ We can get insight about the

Dirac-δ solution..

22 / 24

slide-134
SLIDE 134
  • III. Dirac δ-like boundary conditions

◮ We can observe evidence for logarithmic behaviour of the

backreacted Dirac-δ lattice solution lim

z→0 z ∂φ

∂z = 0

work in progress...

23 / 24

slide-135
SLIDE 135
  • III. Dirac δ-like boundary conditions

◮ We can observe evidence for logarithmic behaviour of the

backreacted Dirac-δ lattice solution lim

z→0 z ∂φ

∂z = 0

work in progress...

23 / 24

slide-136
SLIDE 136
  • III. Dirac δ-like boundary conditions

◮ We can observe evidence for logarithmic behaviour of the

backreacted Dirac-δ lattice solution lim

z→0 z ∂φ

∂z = 0

work in progress...

23 / 24

slide-137
SLIDE 137
  • III. Dirac δ-like boundary conditions

◮ We can observe evidence for logarithmic behaviour of the

backreacted Dirac-δ lattice solution lim

z→0 z ∂φ

∂z = 0

work in progress...

23 / 24

slide-138
SLIDE 138
  • III. Dirac δ-like boundary conditions

◮ We can observe evidence for logarithmic behaviour of the

backreacted Dirac-δ lattice solution lim

z→0 z ∂φ

∂z = 0

work in progress...

23 / 24

slide-139
SLIDE 139

Conclusions

◮ The AdS/CFT correspondence provides a fascinating source of

problems for numerical relativity

◮ These problems arise both in ‘global AdS’ and ‘Poincare patch’

contexts

◮ Sometimes one encounters the need for nonstandard techniques (like

freezing of ADM evolution) and unexpected subtleties (non-Dirichlet boundary conditions at the AdS boundary)

◮ In other cases one encounters novel setups w.r.t. conventional

Numerical Relativity (e.g. very localized Dirac-δ like sources/ boundary conditions)

24 / 24

slide-140
SLIDE 140

Conclusions

◮ The AdS/CFT correspondence provides a fascinating source of

problems for numerical relativity

◮ These problems arise both in ‘global AdS’ and ‘Poincare patch’

contexts

◮ Sometimes one encounters the need for nonstandard techniques (like

freezing of ADM evolution) and unexpected subtleties (non-Dirichlet boundary conditions at the AdS boundary)

◮ In other cases one encounters novel setups w.r.t. conventional

Numerical Relativity (e.g. very localized Dirac-δ like sources/ boundary conditions)

24 / 24

slide-141
SLIDE 141

Conclusions

◮ The AdS/CFT correspondence provides a fascinating source of

problems for numerical relativity

◮ These problems arise both in ‘global AdS’ and ‘Poincare patch’

contexts

◮ Sometimes one encounters the need for nonstandard techniques (like

freezing of ADM evolution) and unexpected subtleties (non-Dirichlet boundary conditions at the AdS boundary)

◮ In other cases one encounters novel setups w.r.t. conventional

Numerical Relativity (e.g. very localized Dirac-δ like sources/ boundary conditions)

24 / 24

slide-142
SLIDE 142

Conclusions

◮ The AdS/CFT correspondence provides a fascinating source of

problems for numerical relativity

◮ These problems arise both in ‘global AdS’ and ‘Poincare patch’

contexts

◮ Sometimes one encounters the need for nonstandard techniques (like

freezing of ADM evolution) and unexpected subtleties (non-Dirichlet boundary conditions at the AdS boundary)

◮ In other cases one encounters novel setups w.r.t. conventional

Numerical Relativity (e.g. very localized Dirac-δ like sources/ boundary conditions)

24 / 24

slide-143
SLIDE 143

Conclusions

◮ The AdS/CFT correspondence provides a fascinating source of

problems for numerical relativity

◮ These problems arise both in ‘global AdS’ and ‘Poincare patch’

contexts

◮ Sometimes one encounters the need for nonstandard techniques (like

freezing of ADM evolution) and unexpected subtleties (non-Dirichlet boundary conditions at the AdS boundary)

◮ In other cases one encounters novel setups w.r.t. conventional

Numerical Relativity (e.g. very localized Dirac-δ like sources/ boundary conditions)

24 / 24