Extreme Holography David Mateos ICREA & University of Barcelona - - PowerPoint PPT Presentation

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Extreme Holography David Mateos ICREA & University of Barcelona - - PowerPoint PPT Presentation

Jun 25, 2023 314 likes •1.06k views

Extreme Holography David Mateos ICREA & University of Barcelona with M. Attems, Y. Bea, J. Casalderrey, A. Faedo, A. Kundu, I. Papadimitriou, C. Pantelidou, D. Santos-Olivn, W. van der Schee, C. F. Sopuerta, J.

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SLIDE 1

David Mateos

ICREA & University of Barcelona

Extreme Holography

with

  • M. Attems,
  • Y. Bea, J. Casalderrey, A. Faedo, A. Kundu, I. Papadimitriou, C. Pantelidou,
  • D. Santos-Oliván, W. van der Schee, C. F. Sopuerta, J. Tarrio, M. Triana and M. Zilhão
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SLIDE 2

QCD in extreme conditions String Theory

Holography

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SLIDE 3
  • All you need to know about:
  • QCD
  • String theory
  • Holography

Plan

  • Holographic heavy ion collisions with phase transitions.
  • Holographic color superconductivity.
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SLIDE 4
  • All you need to know about:
  • QCD
  • String theory
  • Holography

Plan

  • Holographic heavy ion collisions with phase transitions.
  • Holographic color superconductivity.

HOT COLD

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SLIDE 5

QCD

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SLIDE 6

Strength of interaction depends on energy

(E)

ΛQCD ∼ 200 MeV

1

⇥

Why is QCD hard?

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SLIDE 7

(E)

ΛQCD ∼ 200 MeV

1

⇥

Why is QCD hard?

Asymptotic freedom

The Nobel Prize in Physics 2004

  • D. Gross
  • D. Politzer
  • F. Wilczek
  • Can use perturbation theory.
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SLIDE 8

(E)

ΛQCD ∼ 200 MeV

1

⇥

Why is QCD hard?

Strong coupling

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SLIDE 9

(E)

ΛQCD ∼ 200 MeV

1

⇥

Why is QCD hard?

Strong coupling

  • Only 1st-principle systematic tool is lattice formulation

+ supercomputer.

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SLIDE 10

(E)

ΛQCD ∼ 200 MeV

1

⇥

Why is QCD hard?

Strong coupling

  • Limited applicability to non-equilibrium or non-zero

quark density.

  • Only 1st-principle systematic tool is lattice formulation

+ supercomputer.

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SLIDE 11

QCD in extreme conditions

  • QCD at extremely high energy density and/or quark density.
  • In equilibrium, this physics is captured by the QCD phase diagram.
  • For the purpose of this talk:
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SLIDE 12

Quark-Gluon Plasma

T

Hadrons

nq

{q

q, q,

q, q}

{q

¯ q

q, q}¯

q

¯ q

q, q, Tc ~ ΛQCD

QCD phase diagram

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SLIDE 13

Quark-Gluon Plasma

T

Hadrons

nq

{q

q, q,

q, q}

{q

¯ q

q, q}¯

q

¯ q

q, q,

Can be created in the lab via heavy ion collisions at RHIC and LHC

Tc ~ ΛQCD

QCD phase diagram

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SLIDE 14

Quark-Gluon Plasma

T

Hadrons

nq

{q

q, q,

q, q}

{q

¯ q

q, q}¯

q

¯ q

q, q,

1st-order transition Critical point

Tc ~ ΛQCD

QCD phase diagram

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SLIDE 15

QCD in extreme conditions

Quark-Gluon Plasma

T

Hadrons

nq

{q

q, q,

q, q}

{q

¯ q

q, q}¯

q

¯ q

q, q,

1st-order transition Critical point Critical point searched for at RHIC (now) and at FAIR and NICA (future).

Tc ~ ΛQCD

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SLIDE 16

Quark-Gluon Plasma

T

Hadrons

nq

{q

q, q,

q, q}

{q

¯ q

q, q}¯

q

¯ q

q, q,

Critical point

Collision time

thydro

  • Far-from-equilibrium dynamics
  • Hydrodynamics
  • Hadronization

Tc ~ ΛQCD

QCD phase diagram

1st-order transition

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SLIDE 17

Quark-Gluon Plasma

T

Hadrons

nq

{q

q, q,

q, q}

{q

¯ q

q, q}¯

q

¯ q

q, q,

Critical point

Collision time

thydro

  • Far-from-equilibrium dynamics
  • Hydrodynamics
  • Hadronization

Tc ~ ΛQCD

QCD phase diagram

  • Theoretical challenge.
  • W

e will see what holography can say.

1st-order transition

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SLIDE 18

Quark-Gluon Plasma

T

Hadrons

nq

{q

q, q,

q, q}

{q

¯ q

q, q}¯

q

¯ q

q, q, Tc ~ ΛQCD

1st-order transition Critical point Color superconductor

{q,

q, q,

q, q}

q, q,

{q

q, q}

Alford, Rajagopal & Wilczek ’99

QCD phase diagram

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SLIDE 19

Quark-Gluon Plasma

T

Hadrons

nq

{q

q, q,

q, q}

{q

¯ q

q, q}¯

q

¯ q

q, q, Tc ~ ΛQCD

1st-order transition Critical point Color superconductor

{q,

q, q,

q, q}

q, q,

{q

q, q}

Alford, Rajagopal & Wilczek ’99

QCD phase diagram

  • W

e will see what holography can say.

  • Can be studied via weak-coupling methods only at nq → ∞.

Could be realized at the core of neutron stars

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SLIDE 20

String Theory

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SLIDE 21

String theory

  • Perturbatively it is quantum theory of 1-dimensional objects.
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SLIDE 22
  • Different vibration modes behave as particles of

different masses and spins:

M

String theory

  • Perturbatively it is quantum theory of 1-dimensional objects.
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SLIDE 23
  • Different vibration modes behave as particles of

different masses and spins:

M

String theory

  • Perturbatively it is quantum theory of 1-dimensional objects.

M=0, Spin=2: Graviton!

Theory of Quantum Gravity

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SLIDE 24
  • Non-perturbatively, string theory is not only a theory of strings:

D-branes

Open strings

String theory

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SLIDE 25

Holography

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SLIDE 26

quark gluons

QCD-like theory in flat space

Holography from two equivalent descriptions

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SLIDE 27

QCD-like theory in flat space

Holography from two equivalent descriptions

AdS5

String theory in AdS5-like space

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SLIDE 28

Holography from two equivalent descriptions

QCD-like theory in flat space = Boundary of AdS5

AdS5

String theory in AdS5-like space

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SLIDE 29

q

¯ q

Confined

Black Hole

q

Deconfined

QGP = BH

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SLIDE 30

Limitations

  • At present the dual of QCD is not known.
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SLIDE 31
  • Therefore holography is not a tool for precision QCD physics.

Limitations

  • At present the dual of QCD is not known.
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SLIDE 32
  • However, it may still provide useful insights.
  • Therefore holography is not a tool for precision QCD physics.

Limitations

  • At present the dual of QCD is not known.
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SLIDE 33
  • However, it may still provide useful insights.
  • Therefore holography is not a tool for precision QCD physics.
  • In particular, holography is the only first-principle tool if

strong coupling + far from equilibrium.

Limitations

  • At present the dual of QCD is not known.
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SLIDE 34

Holographic Collisions

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SLIDE 35

What we would like to do

Heavy ion collisions in QCD

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SLIDE 36

Caricatures: Lumps of energy and charge Gravitational + electromagnetic waves

Holographic heavy ion collisions

What we can do

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SLIDE 37

Black hole horizon

Formation of the QGP

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SLIDE 38

Holographic heavy ion collisions

Solve classical Einstein equations Read off boundary stress tensor

Strategy

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SLIDE 39

Example: CFT

Incoming shocks Collision region Receding fragments 0.02

Λ

ε/Λ4

QGP

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SLIDE 40

Collisions with a crossover

Attems, Casalderrey, D.M., Santos-Olivan, Sopuerta, Triana & Zilhao ’16

QCD deconfinement is rapid crossover (lattice)

  • Z. Fodor et al ’02

Holographic theory has scale Λ ~ Tc

O

  • Can think of Λ as mass term for dim-3 scalar operator .

Observations:

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SLIDE 41

Many paths to equilibrium

Attems, Casalderrey, D.M., Santos-Olivan, Sopuerta, Triana & Zilhao ’16

  • Define several characteristic times/processes leading to equilibration:

PL

  • Hydrodynamization: and are well described by hydro.
  • PT
  • Isotropization: and become equal.

PL

  • PT

Peq

  • EoSization: and become equal.

¯ P

  • Scalar relaxation: and become equal.

hOieq

hOi

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SLIDE 42

Many paths to equilibrium

Attems, Casalderrey, D.M., Santos-Olivan, Sopuerta, Triana & Zilhao ’17

  • thyd Thyd
  • tEoS Thyd
  • tcond Thyd

tiso much longer

  • Many possible orderings.

Collision energy

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SLIDE 43

Many paths to equilibrium

Attems, Casalderrey, D.M., Santos-Olivan, Sopuerta, Triana & Zilhao ’17

  • thyd Thyd
  • tEoS Thyd
  • tcond Thyd

tiso much longer

  • Many possible orderings.
  • Equilibration is very non-trivial process.

Collision energy

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SLIDE 44
  • thyd Thyd
  • tEoS Thyd
  • tcond Thyd

tiso much longer

  • Many possible orderings.
  • Equilibration is very non-trivial process.

Collision energy

  • Hydrodynamics can be applicable even when “everything looks far from equilibrium”:
  • Without isotropy
  • Without EoS
  • Without scalar relaxation

Many paths to equilibrium

Attems, Casalderrey, D.M., Santos-Olivan, Sopuerta, Triana & Zilhao ’17

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SLIDE 45

Collisions across a 1st-order phase transition

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear) 0.226 0.228 0.230 0.232 0.234 0.236 0.00 0.01 0.02 0.03 0.04

T/Λ

ε/Λ4

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SLIDE 46

Collisions across a 1st-order phase transition

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear) 0.226 0.228 0.230 0.232 0.234 0.236 0.00 0.01 0.02 0.03 0.04

T/Λ

ε/Λ4

0.02

Λ

ε/Λ4

Extremely high energy: Recover CFT result

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SLIDE 47

Collisions across a 1st-order phase transition

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear) 0.226 0.228 0.230 0.232 0.234 0.236 0.00 0.01 0.02 0.03 0.04

T/Λ

ε/Λ4

0.02

Λ

ε/Λ4

0.02

Λ

ε/Λ4

0.02

Λ

ε/Λ4

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SLIDE 48

Collisions across a 1st-order phase transition

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear) 0.226 0.228 0.230 0.232 0.234 0.236 0.00 0.01 0.02 0.03 0.04

T/Λ

ε/Λ4

0.02

Λ

ε/Λ4

0.02

Λ

ε/Λ4

Long-lived, quasi-static blob well described by 2nd-order hydro

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SLIDE 49

Blob well described by 2nd-order hydrodynamics

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear)

Tµν = T ideal

µν

+ ∂spatial + ∂2

spatial

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SLIDE 50

Blob well described by 2nd-order hydrodynamics

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear)

Time evolution at mid-rapidity Snapshots of spatial profile after hydrodynamization

Tµν = T ideal

µν

+ ∂spatial + ∂2

spatial

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SLIDE 51

Blob well described by 2nd-order hydrodynamics

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear)

Time evolution at mid-rapidity

  • Second-order gradients are large.

Tµν = T ideal

µν

+ ∂spatial + ∂2

spatial

Snapshots of spatial profile after hydrodynamization

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SLIDE 52

Blob well described by 2nd-order hydrodynamics

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear)

  • W

e are not doing time evolution, just checking constitutive relations.

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SLIDE 53

Blob well described by 2nd-order hydrodynamics

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear)

  • Problem for time evolution: Hydrodynamics is acausal.

Tµν = T ideal

µν

+ ∂spatial + ∂2

spatial

  • W

e are not doing time evolution, just checking constitutive relations.

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SLIDE 54

Blob well described by 2nd-order hydrodynamics

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear)

  • Problem for time evolution: Hydrodynamics is acausal.

Tµν = T ideal

µν

+ ∂spatial + ∂2

spatial

  • One fix (Muller-Israel-Stewart): Use lower oder equations to get:

T MIS

µν

= T ideal

µν

+ ∂spatial + ∂spatial∂time

  • W

e are not doing time evolution, just checking constitutive relations.

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SLIDE 55

Blob well described by 2nd-order hydrodynamics

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear)

  • Problem for time evolution: Hydrodynamics is acausal.

Tµν = T ideal

µν

+ ∂spatial + ∂2

spatial

  • Produces equivalent descriptions if gradients are small, but not in our case.
  • One fix (Muller-Israel-Stewart): Use lower oder equations to get:

T MIS

µν

= T ideal

µν

+ ∂spatial + ∂spatial∂time

  • W

e are not doing time evolution, just checking constitutive relations.

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SLIDE 56

Blob well described by 2nd-order hydrodynamics

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear)

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SLIDE 57

From 1st-order to 2nd-order to crossover

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear)

0.226 0.228 0.230 0.232 0.234 0.236 0.00 0.01 0.02 0.03 0.04

T/Λ

ε/Λ4

0.215 0.220 0.225 0.230 0.235 0.00 0.01 0.02 0.03 0.04

T/Λ

ε/Λ4

0.215 0.220 0.225 0.230 0.235 0.00 0.01 0.02 0.03 0.04

T/Λ

ε/Λ4

Continous parameter

1st order 2nd order Crossover

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SLIDE 58

From 1st-order to 2nd-order to crossover

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear)

Equilibrium physics is qualitatively very different

0.226 0.228 0.230 0.232 0.234 0.236 0.00 0.01 0.02 0.03 0.04

T/Λ

ε/Λ4

0.215 0.220 0.225 0.230 0.235 0.00 0.01 0.02 0.03 0.04

T/Λ

ε/Λ4

0.215 0.220 0.225 0.230 0.235 0.00 0.01 0.02 0.03 0.04

T/Λ

ε/Λ4

Continous parameter

1st order

Non-zero latent heat

2nd order

Infinite correlation length

Crossover

Neither of the above

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SLIDE 59

From 1st-order to 2nd-order to crossover

Attems, Bea, Casalderrey, D.M., Triana & Zilhao (to appear)

0.226 0.228 0.230 0.232 0.234 0.236 0.00 0.01 0.02 0.03 0.04

T/Λ

ε/Λ4

0.215 0.220 0.225 0.230 0.235 0.00 0.01 0.02 0.03 0.04

T/Λ

ε/Λ4

0.215 0.220 0.225 0.230 0.235 0.00 0.01 0.02 0.03 0.04

T/Λ

ε/Λ4

Continous parameter

1st order 2nd order Crossover

0.02

Λ

ε/Λ4

But off-equilibrium physics is qualitatively very similar

0.02

Λ

ε/Λ4

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SLIDE 60

Holographic Color Superconductivity

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SLIDE 61
  • Consider the theory at non-zero T and non-zero nq.

Holographic color superconductivity

Faedo, Pantelidou, D.M. & Tarrio (in progress)

Black Hole

q

One quark

Black Hole

Non-zero nq

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SLIDE 62
  • Recall that strings are secretly ending on D-branes.

Holographic color superconductivity

Faedo, Pantelidou, D.M. & Tarrio (in progress)

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SLIDE 63
  • Energy can decrease if some D-branes are pulled out.

Holographic color superconductivity

Faedo, Pantelidou, D.M. & Tarrio (in progress)

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SLIDE 64

Holographic color superconductivity

Faedo, Pantelidou, D.M. & Tarrio (in progress)

  • This mechanism is generic at large enough nq.
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SLIDE 65

massless → massive →

  • When this happens some of the gluons become massive.

Holographic color superconductivity

Faedo, Pantelidou, D.M. & Tarrio (in progress)

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SLIDE 66

massless → massive →

  • This signals the onset of color superconductivity.

Holographic color superconductivity

Faedo, Pantelidou, D.M. & Tarrio (in progress)

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SLIDE 67
  • Massive gluons → Color superconductivity
  • Massive photon → EM superconductivity
  • E.g. explains Meissner effect:

Holographic color superconductivity

Faedo, Pantelidou, D.M. & Tarrio (in progress)

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SLIDE 68

Outlook

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SLIDE 69

T

nq

1st-order transition Critical point

Tc

Holographic energy scan

Collisions in model with dynamical charge and adjustable phase diagram:

  • Location of critical point.
  • Critical temperature.
  • Strength of phase transition.
  • Equation of state on both sides.
  • Size of the projectiles.
  • Collision energy.
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SLIDE 70

T

nq

Color superconductor

{q,

q, q,

q, q}

q, q,

{q

q, q}

Holographic color superconductivity

Phenomenology of strongly coupled color superconductors:

  • Equation of state.
  • T

ransport coefficients.

  • Far-from-equilibrium dynamics.
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SLIDE 71

Thank you

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SLIDE 72