Si Signa gnatur ure o of qua quantum cha um chaos i in n op - - PowerPoint PPT Presentation

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Si Signa gnatur ure o of qua quantum cha um chaos i in n op - - PowerPoint PPT Presentation

Si Signa gnatur ure o of qua quantum cha um chaos i in n op operator or entanglement t in 2d 2d CF CFTs MASAHIRO NOZAKI( iTHEMS Riken and UCB) MASAHIRO NOZAKI( iTHEMS Riken and UCB) A postdoc A faculty in China Si Signa gnatur


slide-1
SLIDE 1

Si Signa gnatur ure o

  • f qua

quantum cha um chaos i in n

  • p
  • perator
  • r entanglement

t in 2d 2d CF CFTs

MASAHIRO NOZAKI( iTHEMS Riken and UCB)

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SLIDE 2

MASAHIRO NOZAKI( iTHEMS Riken and UCB)

A postdoc A faculty in China

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SLIDE 3

Si Signa gnatur ure o

  • f qua

quantum cha um chaos i in n

  • p
  • perator
  • r entanglement

t in 2d 2d CF CFTs

MASAHIRO NOZAKI( iTHEMS Riken and UCB)

Based on the collaboration with

Shinsei Ryu, Laimei Nie, Mao Tian Tan, Jonah Kudler-Flam, Eric Mascot, and Masaki Tezuka

arXiv:1812.00013 [hep-th] arXiv:19xx.xxxxx [hep-th]

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SLIDE 4

Contents of my talk

  • 1. Introduction
  • Thermalization
  • Scrambling
  • 2. Operator entanglement
  • 3. Motivation
  • 4. Brief summary
  • 5. Operator mutual information and logarithmic negativity
  • Bipartite
  • Tripartite
  • 6. Random unitary circuit (See Jonah’s poster)
  • Line tension picture
  • 7. Local operator entanglement (work in progress)
  • 8. Summary and future direction
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SLIDE 5

Thermalization

A A A

Ψ1

0,

Ψ2

0,

, Ψ3

0,

  • Ψi
  • are initial states.
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SLIDE 6

Thermalization

A A A

Ψ1

0,

Ψ2

0,

, Ψ3

0,

  • Ψi
  • are initial states.

Local observables in A depend on initial condition.

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SLIDE 7

Thermalization

A A A

Ψ1

0,

Ψ2

0,

, Ψ3

0,

  • U(t),
  • A

A A

Ψ1

0,

Ψ2

0,

, Ψ3

0,

  • Ψi(t)
  • = U(t)
  • Ψi
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SLIDE 8

Thermalization

A A A

Ψ1

0,

Ψ2

0,

, Ψ3

0,

A

, lim

t→∞ U(t)

  • Ψi

late

  • = lim

t→∞ U(t)

  • Ψi
  • →∞
  • trB
  • Ψi

late

Ψi

late

  • ≃ trBe−βH
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SLIDE 9

Thermalization

A A A

Ψ1

0,

Ψ2

0,

, Ψ3

0,

A

, lim

t→∞ U(t)

  • Ψi

late

  • = lim

t→∞ U(t)

  • Ψi
  • →∞
  • trB
  • Ψi

late

Ψi

late

  • ≃ trBe−βH

Thermalization

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SLIDE 10

Thermalization

A A A

Ψ1

0,

Ψ2

0,

, Ψ3

0,

A

, lim

t→∞ U(t)

  • Ψi

late

  • = lim

t→∞ U(t)

  • Ψi
  • →∞
  • trB
  • Ψi

late

Ψi

late

  • ≃ trBe−βH

Th This is the definition of thermalization in my talk

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SLIDE 11

Thermalization

A A A

Ψ1

0,

Ψ2

0,

, Ψ3

0,

A

, lim

t→∞ U(t)

  • Ψi

late

  • = lim

t→∞ U(t)

  • Ψi
  • →∞
  • trB
  • Ψi

late

Ψi

late

  • ≃ trBe−βH

In Indep epen enden ent

  • f
  • f initial states

es, lo locally ally.

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SLIDE 12

Thermalization

Ex.

States can be approximated by thermal state, locally . ⎪ ⎪ ⎨ ⎪ ⎪ ⎩ − ⟨Ψ(t)| O |Ψ(t)⟩ → tr

  • ρthO
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SLIDE 13

Thermalization

Ex.

States can be approximated by thermal state, locally .

Thermalize!!

Thermalization depends on

(1) Initial state, (2)Dynamics.

⎪ ⎪ ⎨ ⎪ ⎪ ⎩ − ⟨Ψ(t)| O |Ψ(t)⟩ → tr

  • ρthO
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SLIDE 14

Thermalization

Ex.

States can be approximated by thermal state, locally .

Thermalize!!

Key point: Locally, states forget the initial conditions.

⎪ ⎪ ⎨ ⎪ ⎪ ⎩ − ⟨Ψ(t)| O |Ψ(t)⟩ → tr

  • ρthO
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SLIDE 15

Scrambling

Ex.

States can be approximated by thermal state, locally .

Thermalize!!

Key point: Locally, states forget the initial conditions. Scrambling effect

⎪ ⎪ ⎨ ⎪ ⎪ ⎩ − ⟨Ψ(t)| O |Ψ(t)⟩ → tr

  • ρthO
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SLIDE 16

Key point: Locally, states forget the initial condition. Scrambling effect

Scrambling effect depends on time evolution operator.

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SLIDE 17

Key point: Locally, states forget the initial condition. Scrambling effect

Scrambling effect depends on time evolution operator. I would like to know how the scrambling effect depends on the unitary channels.

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SLIDE 18

Key point: Locally, states forget the initial condition. Scrambling effect

Scrambling effect depends on time evolution operator.

I would like to quantify scrambling effect.

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SLIDE 19

Key point: Locally, states forget the initial condition. Scrambling effect

Scrambling effect depends on time evolution operator.

To understand scrambling leads to understanding thermalization.

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SLIDE 20

Scrambling

Space

  • utput

input B A time

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SLIDE 21

Scrambling Co Correla latio tion betw tween A and and B

How much information sent from A to B due to

Exp Expect ctation

  • n

Space

  • utput

input B A time

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SLIDE 22

Scrambling No No co correlation between A and and B Exp Expect ctation

  • n

Signatu ture re of

  • f (ma

maxi xima mally) y) scra cramb mbling

Space

  • utput

input B A time

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SLIDE 23

Concept

Space

  • utput

input A B

We We would like to study the correlation between A A and and B B by by studying op

  • pera

rator

  • r entangleme

ment, , wh which ch is independent of

  • f state.

No No co correlation between A and and B Signatu ture re of

  • f (ma

maxi xima mally) y) scra cramb mbling Exp Expect ctation

  • n
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SLIDE 24

Operator entanglement

Unitary channel: Channel-state dual map:

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SLIDE 25

Operator entanglement

Unitary channel: Channel-state dual map:

Dual state: Hilbert space:

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SLIDE 26

Operator entanglement

Unitary channel: Channel-state dual map:

A regulator for normalization. Dual state: Hilbert space:

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SLIDE 27

Operator entanglement

Unitary channel: Channel-state dual map:

Only this depends on the initial state. Dual state: Hilbert space:

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SLIDE 28

Operator entanglement

Unitary channel: Channel-state dual map:

Dual state: Hilbert space:

Our initial state

Energy eigenstate

⎪ ⎩ |Initial⟩ = N

1

  • a

Ca |a⟩ ≈ N

  • a

Cae−H |a⟩

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SLIDE 29

Operator entanglement

Unitary channel: Channel-state dual map:

Dual state: Hilbert space:

Our initial state

Energy eigenstate

⎪ ⎩ |Initial⟩ = N

1

  • a

Ca |a⟩ ≈ N

  • a

Cae−H |a⟩

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SLIDE 30

Operator entanglement

Unitary channel: Channel-state dual map:

Dual state: Hilbert space:

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SLIDE 31

Space

  • utput

input A

Scrambling

B A B

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SLIDE 32

Space

  • utput

input A

Concept

B A B

Correlation between input and output subsystems Correlation between A and B in .

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SLIDE 33

Space

  • utput

input A

Concept

B A B

Correlation between input and output subsystems Correlation between A and B in . Measured by mutual information .

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SLIDE 34

Space

  • utput

input A

Concept

B A B

Correlation between input and output subsystems Correlation between A and B in . Measured by , .

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SLIDE 35

Motivation

Which CFT (QFT) shows a signature of scrambling ?

Spin system: [Hosur-Qi-Roberts-Yoshida’16]

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SLIDE 36

Motivation

How much information from A to B are scrambled due to channels in field theory?

Spin system: [Hosur-Qi-Roberts-Yoshida’16]

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SLIDE 37

Space

  • utput

input

B A

Results (Main1) No No c correl elat ation n be between een A and nd any B No No o

  • ne i

ne in o n out utput put s sub ubsystem em can’t get quantum information lo locally lly. Signatu ture re of

  • f

ma maxima mally y scra ramb mbling

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SLIDE 38

Space

  • utput

input

B A

Results (Main1) No No c correl elat ation n be between een A and nd any B

Holographic channel

For disjoint or late-time case, for any B,

⟩ , E(A, B) = 0

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SLIDE 39

Space

  • utput

input

B A

Results (Main1) No No c correl elat ation n be between een A and nd any B

Holographic channel

Holographic c ch channel shows a signature of scr crambling.

For disjoint or late-time case, for any B,

⟩ , E(A, B) = 0

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SLIDE 40

Results (Main2)

is the whole of output system.

A

Output system Input system Time

t

B B B

1 2

B B1 and are the halves of output system. B2 A is subsystem in input system.

We have computed tri-partite operator mutual information:

I(A, B) = SA + SB − SA∪B

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SLIDE 41

Results (Main2)

is the whole of output system.

A

Output system Input system Time

t

B B B

1 2

B B1 and are the halves of output system. B2 A is subsystem in input system.

We have computed tri-partite operator logarithmic negativity:

  • E3(A, B1, B2) ≡ E(A, B1) + E(A, B2) − E(A, B)
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SLIDE 42

2d free fermion channel

is the whole of output system.

A

Output system Input system Time

t

B B B

1 2

B B1 and are the halves of output system. B2 A is subsystem in input system.

,E3(A, B1, B2) = 0

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SLIDE 43

2d free fermion channel

is the whole of output system.

A

Output system Input system Time

t

B B B

1 2

B B1 and are the halves of output system. B2 A is subsystem in input system.

This can be interpreted in terms of the relativistic propagation of local objects (quasi-particles) . ,E3(A, B1, B2) = 0

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SLIDE 44

2d chaotic channel (holographic channel)

is the whole of output system.

A

Output system Input system Time

t

B B B

1 2

B B1 and are the halves of output system. B2 A is subsystem in input system.

Late time: E

≡ E E − E E3(A, B1, B2) → −2 × 3 4S(1/2)

A

= −2EA, ¯

A

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SLIDE 45

2d chaotic channel (holographic channel)

is the whole of output system.

A

Output system Input system Time

t

B B B

1 2

B B1 and are the halves of output system. B2 A is subsystem in input system.

Late time: E

≡ E E − E E3(A, B1, B2) → −2 × 3 4S(1/2)

A

= −2EA, ¯

A

0, ¯ A 0, ¯ A

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SLIDE 46

2d chaotic channel (holographic channel)

is the whole of output system.

A

Output system Input system Time

t

B B B

1 2

B B1 and are the halves of output system. B2 A is subsystem in input system.

Late time: E

≡ E E − E E3(A, B1, B2) → −2 × 3 4S(1/2)

A

= −2EA, ¯

A

Lower bound

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SLIDE 47

2d chaotic channel (holographic channel)

is the whole of output system.

A

Output system Input system Time

t

B B B

1 2

B B1 and are the halves of output system. B2 A is subsystem in input system.

Late time: E

≡ E E − E E3(A, B1, B2) → −2 × 3 4S(1/2)

A

= −2EA, ¯

A

Lower bound We expect QFT-channels with strong scrambling ability to satisfy this lower bound, eventually.

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SLIDE 48

2d chaotic channel (holographic channel)

is the whole of output system.

A

Output system Input system Time

t

B B B

1 2

B B1 and are the halves of output system. B2 A is subsystem in input system.

Late time: E

≡ E E − E E3(A, B1, B2) → −2 × 3 4S(1/2)

A

= −2EA, ¯

A

This shows all information is scrambled.

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SLIDE 49

How channels scrambles information

Scrambling Unscrambling

Free fermion channel Compact boson channel

Scrambling channel (maximally scramble)

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SLIDE 50

Bipartite operator mutual information in the replica trick

A B

Setup:

What we compute is

State:

I(A, B) = SA + SB − SA∪B = lim

n→1

  • S(n)

A

+ S(n)

B

− S(n)

A∪B

  • = lim

n→1

1 1 − n [log trA (ρA)n + log trB (ρB)n − log trA∪B (ρA∪B)n]

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SLIDE 51

A B

Setup:

B A A B

Bipartite operator mutual information in the replica trick

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SLIDE 52

B A A B

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SLIDE 53

B A A B

: Twist operator in A : Twist operator in B

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SLIDE 54

B A A B

: Twist operator in A : Twist operator in B

Independent of channels

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SLIDE 55

B A A B

: Twist operator in A : Twist operator in B

Depend on channels!!

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SLIDE 56

− I(A, B) = lim

n→1

1 1 − n [log trA (ρA)n + log trB (ρB)n − log trA∪B (ρA∪B)n]

Bipartite operator mutual information in the replica trick

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SLIDE 57

Bipartite operator mutual information in the replica trick

E EA,B = lim

ne→1 log

  • trA∪B
  • ρTB

A∪B

ne

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SLIDE 58

Bipartite operator mutual information in the replica trick

E EA,B = lim

ne→1 log

  • trA∪B
  • ρTB

A∪B

ne

B A

  • TB
  • σne
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SLIDE 59

Bipartite operator mutual information in the replica trick

E EA,B = lim

ne→1 log

  • trA∪B
  • ρTB

A∪B

ne

B A

  • TB

  • ∼ log
  • σA

ne¯

σA

ne¯

σB

neσB ne

  • σne
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SLIDE 60

Free fermion channel

We consider the following setups to extract properties of free fermion channel:

  • 1. Fully overlapping case

A B A B A B

  • 2. Partially overlapping case
  • 3. Disjoint case
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SLIDE 61

1.

  • 1. F

Fully o

  • verl

rlapping c case

A B

Red cu curve : Purple cu curve : Blue cu curve :

  • I(A, B)
  • ) t
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SLIDE 62

2.

  • 2. P

Part rtially o

  • verl

rlapping c case

A B

Red cu curve : Purple cu curve : Blue cu curve :

  • I(A, B)
  • ) t
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SLIDE 63

3.

  • 3. D

Disjoi

  • int c

case

A B

Red cu curve : Purple cu curve : Blue cu curve :

  • I(A, B)
  • ) t
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SLIDE 64

3.

  • 3. D

Disjoi

  • int c

case

A B

Red cu curve : Purple cu curve : Blue cu curve :

  • I(A, B)
  • ) t

Ti Time evolution of operator logarithmic is quite si similar to operator mutual information.

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SLIDE 65
  • I(A, B)
  • ) t
  • ) t
  • I(A, B)
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SLIDE 66
  • I(A, B)
  • ) t
  • ) t
  • I(A, B)

Slopes and bumps shows properties of free fermion ch

channel are interpreted in terms of the relativistic c propagation of quasi-particl cles.

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SLIDE 67

Tripartite operator mutual information

A B B1 B2

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SLIDE 68

A B B1 B2

do does esn’ n’t depend o depend on t n the t he time and t e and the c he cho hoice f e for su subsys ystems. s. Tripartite operator mutual information

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SLIDE 69

Tripartite operator logarithmic negativity

A B B1 B2

E3(A, B1, B2) ) =

  • ≡ E(A, B1) + E(A, B2)
  • ) − E(A, B1 ∪ B2)
  • t E3(A, B1, B2) = 0

I(A, B1, B2) = 0

Re Relativistic propagation

  • f
  • f quasi

si-par particle. e.

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SLIDE 70

Toy model

The time evolution of operator mutual information (logarithmic negativity) and tripartite operator mutual information (logarithmic negativity) for free fermion channel can be interpreted in terms of the relativistic propagation of local

  • bjects as follows:
  • 1. Each point in the input subsystem A has two particles.
  • One of them propagates in the right direction ( ) at speed of light.
  • The other ( ).
  • particle size .
  • # of particles in A is proportional to

the input subsystem size .

A

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SLIDE 71

Toy model

  • 2. The particles in the output subsystem B contribute to .
  • B

# of particles in B.

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SLIDE 72

2.

  • 2. P

Part rtially o

  • verl

rlapping c case

A B

Red cu curve :

A B

Purple cu curve :

A B

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SLIDE 73

3.

  • 3. D

Disjoi

  • int c

case

A B

Red cu curve : Purple cu curve : Blue cu curve :

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SLIDE 74

3.

  • 3. D

Disjoi

  • int c

case

A B

Red cu curve : Purple cu curve : Blue cu curve :

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SLIDE 75

3.

  • 3. D

Disjoi

  • int c

case

A B

Red cu curve : Purple cu curve : Blue cu curve :

A B

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SLIDE 76

3.

  • 3. D

Disjoi

  • int c

case

A B

Red cu curve : Purple cu curve : Blue cu curve :

A B A B

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SLIDE 77

3.

  • 3. D

Disjoi

  • int c

case

A B

Red cu curve : Purple cu curve : Blue cu curve :

A B A B A B

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SLIDE 78

Tri-partite information

  • Tri-partite information can be interpreted in terms of the relativistic

propagation of local objects, too.

A B

1 2

B B

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SLIDE 79

Tri-partite information

  • Tri-partite information can be interpreted in terms of the relativistic

propagation of local objects, too.

A B

1 2

B B

@time =0

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SLIDE 80

Tri-partite information

  • Tri-partite information can be interpreted in terms of the relativistic

propagation of local objects, too.

A B

1 2

B B

@time =0

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SLIDE 81

Tri-partite information

  • Tri-partite information can be interpreted in terms of the relativistic

propagation of local objects, too.

A B

1 2

B B

@time =0

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SLIDE 82

Tri-partite information

  • Tri-partite information can be interpreted in terms of the relativistic

propagation of local objects, too.

A B

1 2

B B

@time =0

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SLIDE 83

Tri-partite information

  • Tri-partite information can be interpreted in terms of the relativistic

propagation of local objects, too.

B B B

1 2

@time = t

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SLIDE 84

Tri-partite information

  • Tri-partite information can be interpreted in terms of the relativistic

propagation of local objects, too.

B

1 2

B B

@time = t

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SLIDE 85

Tri-partite information

  • Tri-partite information can be interpreted in terms of the relativistic

propagation of local objects, too.

B

1 2

B B

@time = t

Op Oper erator mutual information for free ee fe fermion channel can be interpreted in te terms of the relativistic propagation of lo local o al obj bject s suc uch as h as quas quasi-part partic icle les. s.

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SLIDE 86

Tri-partite information

  • Tri-partite information can be interpreted in terms of the relativistic

propagation of local objects, too.

B

1 2

B B

@time = t

Fo For free fermion channel, quantum correlation be between input n input and o and out utput put sub subsystems is s is ex explained by lo local o al obj bject (quas (quasi-part partic icle les)! s)!!

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SLIDE 87

Tri-partite information

  • Tri-partite information can be interpreted in terms of the relativistic

propagation of local objects, too.

B

1 2

B B

@time = t

Qu Quantum information for free fermion ch channel el is s carried ed by lo local o al obj bject (quas (quasi- part partic icle les)! s)!!

slide-88
SLIDE 88

Comparison

We consider the following setups to extract properties of compact boson and holographic channels by comparing them to free fermion channel:

  • 1. Fully overlapping case

A B A B A B

  • 2. Partially overlapping case
  • 3. Disjoint case
slide-89
SLIDE 89

Comparison

We consider the following setups to extract properties of compact boson and holographic channels by comparing them to free fermion channel:

  • 1. Fully overlapping case

A B A B A B

  • 2. Partially overlapping case
  • 3. Disjoint case
slide-90
SLIDE 90

2.

  • 2. P

Part rtially o

  • verl

rlapping c case

Holographic channel:

A B

:Blue :Red :Purple :Black dash Red Black Blue Purple

Free fermion channel: Compact boson channel:

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SLIDE 91

2.

  • 2. P

Part rtially o

  • verl

rlapping c case

Holographic channel:

A B

:Blue :Red :Purple :Black dash Red Black Blue Purple

Free fermion channel: Compact boson channel:

Qu Quasi-par particle pi pictur ure w works w well.

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SLIDE 92

2.

  • 2. P

Part rtially o

  • verl

rlapping c case

FF channel:

CB channel:

Holographic channel:

A B

:Blue :Red :Purple :Black dash

Ho Hologra raphic channel el does esn’t show w a platea eau.

Red Blue Purple Black

slide-93
SLIDE 93

2.

  • 2. P

Part rtially o

  • verl

rlapping c case

FF channel:

CB channel:

Holographic channel:

A B

:Blue :Red :Purple :Black dash

Thi This pr prope perty i is be beyond t nd the he par particle i interpr pretat ation. n.

Red Blue Purple Black

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SLIDE 94

Ho Holo lographic aphic channel hannel

A B

Red Black Blue Purple

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SLIDE 95

Ho Holo lographic aphic channel hannel

A B

Red Black Blue Purple

Monotonically y decreasing On Once ce quantum information le leak aks from B, , it keeps to leak k be before al all i inf nformat ation l n leak aks.

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SLIDE 96

Ho Holo lographic aphic channel hannel

A B

Red Black Blue Purple

Monotonically y decreasing On Once ce quantum information le leak aks from B, , it keeps to leak k be before al all i inf nformat ation l n leak aks. If If quantum inform rmation is carri rried ed by y local objects,

th this is does esn’t t hap appen en!! !!

slide-97
SLIDE 97

Ho Holo lographic aphic channel hannel

A B Th The slo lope chan anges at .

Red Blue Purple Black

slide-98
SLIDE 98

Heur Heuris istic tic explana planatio tion n

A B

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SLIDE 99

Heur Heuris istic tic explana planatio tion n

A B Quantum information keeps s to go out from the left boundary y wi with . At At t=0, right-mo moving ng signal gnal appe appear ars at at the he righ ght bo boundar undary of A. . It Its speed eed is is the e lig light’s.

slide-100
SLIDE 100

Heur Heuris istic tic explana planatio tion

A B A B

slide-101
SLIDE 101

Heur Heuris istic tic explana planatio tion

A B A B Wh When en the e rig ight-moving g si sign gnal hits s the righ ght bo bounda undary of B, the the inform rmati tion n starts rts to go

  • u
  • ut from
  • m B

B wi with .

slide-102
SLIDE 102

Heur Heuris istic tic explana planatio tion

A B A B de decrease ses s tw twice faster tha than n tha that t in n . in

slide-103
SLIDE 103

Heur Heuris istic tic explana planatio tion

A B A B Al All the the informati tion n of A A go goes o

  • ut

ut f from m B B @ @ t= t=l +s/2.

slide-104
SLIDE 104

Ho Holo lographic aphic channel hannel

A B

Red Blue Purple

Fo For , lin linearly rly decr creases .

Black

@ @ .

slide-105
SLIDE 105

Heur Heuris istic tic explana planatio tion n

A B

Al All the informa mation of A A goes ou

  • ut

t fr from the left ft boundary of f B be before the he signa nal arrives at the he ri right boundary. Once ce whole in informatio ion has as gone, the sig ignal al di disappe ppears.

slide-106
SLIDE 106

Heur Heuris istic tic explana planatio tion n

A B Al All the the informati tion n in n A A goes

  • u
  • ut from
  • m the

e left bou

  • undary of
  • f

B be before the the si signa gnal arrives s at t the the ri right t bo bounda

  • undary. The

he signa nal di disa sappe ppears. s. Ea Early time:

Qu Quasi-par particle des e description w n works w wel ell.

La Late ti time: :

We We need some description (Li Line t ne tens ension pi n pictur ure). ).

slide-107
SLIDE 107

3.

  • 3. D

Disjoi

  • int i

interval

:Blue :Red :Purple :Black dash

A B

If A and B are disjoint( ),

Holographic channel: Free fermion channel: Compact boson channel:

slide-108
SLIDE 108

FF channel:

3.

  • 3. D

Disjoi

  • int i

interval

CB channel:

Holographic channel:

:Blue :Red :Purple :Black dash

A B

If A and B are disjoint( ),

Time evolution can be interpreted in terms of particles, almost.

slide-109
SLIDE 109

FF channel:

3.

  • 3. D

Disjoi

  • int i

interval

CB channel:

Holographic channel:

:Blue :Red :Purple :Black dash

A B

If A and B are disjoint( ),

A A surprising property

  • f
  • f hol
  • log
  • gra

raphic c ch channel.

slide-110
SLIDE 110

FF channel:

3.

  • 3. D

Disjoi

  • int i

interval

CB channel:

Holographic channel:

:Blue :Red :Purple :Black dash

A B

If A and B are disjoint( ),

A A surprising property

  • f
  • f hol
  • log
  • gra

raphic c ch channel.

Information Scrambling.

slide-111
SLIDE 111

Fr Free ee fer ermio ion n channel hannel

Space

  • utput

input

B A

Bumps

slide-112
SLIDE 112

Bumps Can be interpreted in terms of particles

Fr Free ee fer ermio ion n channel hannel

Space

  • utput

input

B A

slide-113
SLIDE 113

Fr Free ee fer ermio ion n channel hannel A B

t = 0

@

slide-114
SLIDE 114

Fr Free ee fer ermio ion n channel hannel A B

t = 0

@

Here, you can get information locally.

slide-115
SLIDE 115

Fr Free ee fer ermio ion n channel hannel

t = 0

@

t = t1

@

Here, you can get information locally.

slide-116
SLIDE 116

Fr Free ee fer ermio ion n channel hannel

t = 0

@

t = t1

@

Here, you can get information locally.

@

Here, you can get information locally.

t = t2

slide-117
SLIDE 117

Fr Free ee fer ermio ion n channel hannel

t = 0

@

t = t1

@

Here, you can get information locally.

@

Here, you can get information locally.

t = t2

By changing the position of B, you can get information locally.

slide-118
SLIDE 118

Ho Holo lographic aphic channel hannel

Space

  • utput

input

B A

For disjoint or late-time case, for any B

slide-119
SLIDE 119

Ho Holo lographic aphic channel hannel

Space

  • utput

input

B A

For disjoint or late-time case, for any B

Beyond the quasi-particle model

slide-120
SLIDE 120

Ho Holo lographic aphic channel hannel

t = t1

@

Everywhere , you can’t get information locally at late time .

slide-121
SLIDE 121

Ho Holo lographic aphic channel hannel

Space

  • utput

input

B A

For disjoint or late-time case, for any B

Beyond the quasi-particle model We cannot mine the information in A from B locally.

slide-122
SLIDE 122

Ho Holo lographic aphic channel hannel

Space

  • utput

input

B A

Beyond the quasi-particle model We cannot mine the information in A from B locally.

Signature of information scrambling

For disjoint or late-time case, for any B

slide-123
SLIDE 123

Ho Holo lographic aphic channel hannel

Space

  • utput

input

B A

Beyond the quasi-particle model We cannot mine the information in A from B locally.

Signature of information scrambling

Ca Can we tr treat t th the effect t of in informatio tion scramblin ling quantit titativ tively ly?

For disjoint or late-time case, for any B

slide-124
SLIDE 124

(It might be different from usual one… Sorry.)

A definition of (maximally) Information scrambling

We cannot mine any information about A locally, but we can mine the information from the whole of output system.

slide-125
SLIDE 125

A definition of (maximally) Information scrambling

We cannot mine any information about A locally, but we can mine the information from the whole of output system.

B A B1

0 E(A, B1) = 0

slide-126
SLIDE 126

A definition of (maximally) Information scrambling

We cannot mine any information about A locally, but we can mine the information from the whole of output system.

B A B1 B A

0 E(A, B1) = 0

0 E(A, B) ̸= 0

slide-127
SLIDE 127

Tripartite information (Tripartite logarithmic negativity) is useful quantity in order to treat this phenomenon, quantitatively.

A definition of (maximally) Information scrambling

We cannot mine any information about A locally, but we can mine the information from the whole of output system.

[Hosur-Qi-Roberts-Yoshida’16]

slide-128
SLIDE 128

Tripartite operator mutual information

Output system Input subsystem

B B B

1 2

A

is the whole of output system.

B B 1 and are the halves of output system. B

A is a subsystem in input system.

2

slide-129
SLIDE 129

the information of A from the whole of output system B.

Output system Input subsystem

B B B

1 2

A

is the whole of output system.

B B 1 and are the halves of output system. B

A is a subsystem in input system.

2

B A

Tripartite operator mutual information

slide-130
SLIDE 130

the information of A from the whole of output system B.

Output system Input subsystem

B B B

1 2

A

is the whole of output system.

B B 1 and are the halves of output system. B

A is a subsystem in input system.

2

B A B 2 A B 1

the information of A from the subsystems.

Tripartite operator mutual information

slide-131
SLIDE 131

the information of A from the whole of output system B.

Output system Input subsystem

B B B

1 2

A

is the whole of output system.

B B 1 and are the halves of output system. B

A is a subsystem in input system.

2

B A B 2 A B 1

the information of A from the subsystems.

Tripartite operator mutual information

slide-132
SLIDE 132

Tripartite operator logarithmic negativity

the information of A from the whole of output system B.

Output system Input subsystem

B B B

1 2

A

is the whole of output system.

B B 1 and are the halves of output system. B

A is a subsystem in input system.

2

B A B 2 A B 1

the information of A from the subsystems.

  • E

E3(A, B1, B2) = E(A, B1) + E(A, B2) − E(A, B)

slide-133
SLIDE 133

Tripartite operator mutual information (logarithmic negativity)

If information mined from subsystems and is smaller than the information from whole of output system ,

E B1 B2 B

slide-134
SLIDE 134

Tripartite operator mutual information (logarithmic negativity)

If information mined from subsystems and is smaller than the information from whole of output system ,

) B1

1 B2

I(A, B1) + I(A, B2) ) E(A, B1) + E(A, B2)

B

slide-135
SLIDE 135

Tripartite operator mutual information (logarithmic negativity)

If information mined from subsystems and is smaller than the information from whole of output system ,

) B1

1 B2

I(A, B1) + I(A, B2) ) E(A, B1) + E(A, B2) B − B − A, B E I(A, B) E ) E(A, B) − < 0 − < 0

slide-136
SLIDE 136

Tripartite operator mutual information (logarithmic negativity)

If information mined from subsystems and is smaller than the information from whole of output system ,

) B1

1 B2

I(A, B1) + I(A, B2) ) E(A, B1) + E(A, B2) B − B − A, B E I(A, B) E ) E(A, B) − < 0 − < 0

E E , E3(A, B1, B2) < 0

slide-137
SLIDE 137

Tripartite operator mutual information (logarithmic negativity)

If information mined from subsystems and is smaller than the information from whole of output system ,

) B1

1 B2

I(A, B1) + I(A, B2) ) E(A, B1) + E(A, B2) B − B − A, B E I(A, B) E ) E(A, B) − < 0 − < 0

E E , E3(A, B1, B2) < 0

Some information is hidden in whole of output system due to information scrambling effect.

This quantity can quantify the effect of information scrambling.

slide-138
SLIDE 138

Holographic channel

A

Output system Input system Time

t

B B B

1 2

Setup:

slide-139
SLIDE 139

Holographic channel

10 20 30 40

  • 4
  • 3
  • 2
  • 1

10 20 30 40

  • 3.0
  • 2.5
  • 2.0
  • 1.5
  • 1.0
  • 0.5

E E3(A, B1, B2) → −2E(A, ¯ A)

@ late time,

slide-140
SLIDE 140

Holographic channel

Constant

At late time,

We cannot mine information locally, but we can mine the information about A from the whole of output system B.

  • E

E3(A, B1, B2) = E(A, B1) + E(A, B2) − E(A, B)

slide-141
SLIDE 141

Holographic channel

Constant

At late time,

We cannot mine information locally, but we can mine the information about A from the whole of output system B.

  • E

E3(A, B1, B2) = E(A, B1) + E(A, B2) − E(A, B)

slide-142
SLIDE 142

Holographic channel

Constant

At late time,

We cannot mine information locally, but we can mine the information about A from the whole of output system B.

  • E

E3(A, B1, B2) = E(A, B1) + E(A, B2) − E(A, B)

slide-143
SLIDE 143

Holographic channel

Constant

At late time,

We cannot mine information locally, but we can mine the information about A from the whole of output system B.

  • E

E3(A, B1, B2) = E(A, B1) + E(A, B2) − E(A, B)

All information sent from A is scrambled.

slide-144
SLIDE 144

Holographic channel

Constant

At late time,

We cannot mine information locally, but we can mine the information about A from the whole of output system B.

  • E

E3(A, B1, B2) = E(A, B1) + E(A, B2) − E(A, B)

They measure how much information is scrambled.

slide-145
SLIDE 145

Holographic channel

10 20 30 40

  • 4
  • 3
  • 2
  • 1

10 20 30 40

  • 3.0
  • 2.5
  • 2.0
  • 1.5
  • 1.0
  • 0.5

E E3(A, B1, B2) → −2E(A, ¯ A)

@ late time,

In In the lo low energ rgy lim limit it,

these ki kinks can be negligible.

.

slide-146
SLIDE 146

Bipartite operator mutual information (logarithmic negativity)

t = t1

Here, you can get information locally.

@

Free fermion and Compact boson channels: Holographic channel:

Everywhere , you can’t get information locally.

t = t1

@

Summary

slide-147
SLIDE 147

Tripartite operator mutual information (Tripartite operator logarithmic negativity)

Free fermion channels:

Summary

I(A, B1, B2) = 0

B B B

1 2

Quasi-particles

Holographic channel:

All initial information is scrambled.

E3(A, B1, B2) = 0

E E3(A, B1, B2) → −2E(A, ¯ A)

slide-148
SLIDE 148
  • 1. Operator entanglement of local operator
  • 2. Complexity
  • 3. Operator entanglement of CMERA
  • 4. Many-body localization
  • 5. Quantum Chaos and thermalization
  • 6. Wormhole (double trace deformation)

Future directions