Complementarity -...

Post on 17-Oct-2020

1 views 0 download

Transcript of Complementarity -...

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Kind of old news now:

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Phase Groups and Complementarity

Ross DuncanOxford University Computing Laboratory

α

α

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Motivations

A⇒ B

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Motivations

A⇒ B !A−◦B

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Motivations

A⇒ B !A−◦B

Hilbert space, unitary transforms,

self-adjoint operators.... ?

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Motivations

A⇒ B !A−◦B

Hilbert space, unitary transforms,

self-adjoint operators....

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

What we did:

We reformulated (a large part of) quantum mechanics:

• high level structural approach based on monoidal categories

• axiomatics expressive enough to cover universal quantum computation

- and powerful enough to simulate algorithms and prove equivalence between quantum state and programs

• simple to understand and manipulate graphical calculus

- which is being implemented in semi-automatic GUI based rewriting tool

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

In This Talk:

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

In This Talk:

Observables

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

In This Talk:

Observables Special †-Frobenius Algebrasaka classical structures

aka basis structuresaka observable structures

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

In This Talk:

Observables Special †-Frobenius Algebrasaka classical structures

aka basis structuresaka observable structures

Phase Groups

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

In This Talk:

Observables Special †-Frobenius Algebrasaka classical structures

aka basis structuresaka observable structures

Phase Groups

MutuallyUnbiased Bases

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

In This Talk:

Observables Special †-Frobenius Algebrasaka classical structures

aka basis structuresaka observable structures

Phase Groups

MutuallyUnbiased Bases

Complementary

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

In This Talk:

Observables Special †-Frobenius Algebrasaka classical structures

aka basis structuresaka observable structures

Phase Groups

MutuallyUnbiased Bases

Hopf Algebras &BialgebrasComplementary

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

In This Talk:

Observables Special †-Frobenius Algebrasaka classical structures

aka basis structuresaka observable structures

Phase Groups

MutuallyUnbiased Bases

Hopf Algebras &BialgebrasComplementary

Automorphisms of

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

What is a Phase Group?

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

What is a Phase Group?

• An abelian group of unitary maps on the state space

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

What is a Phase Group?

• An abelian group of unitary maps on the state space

• which leave some observable fixed

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

What is a Phase Group?

• An abelian group of unitary maps on the state space

• which leave some observable fixed

α

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Ingredients of the Theory

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Ingredients of the Theory

To construct phase groups we need:

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Ingredients of the Theory

To construct phase groups we need:

• Tensor products:

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Ingredients of the Theory

To construct phase groups we need:

• Tensor products:

- Symmetric monoidal categories

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Ingredients of the Theory

To construct phase groups we need:

• Tensor products:

- Symmetric monoidal categories

• Unitarity:

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Ingredients of the Theory

To construct phase groups we need:

• Tensor products:

- Symmetric monoidal categories

• Unitarity:

- †-symmetric monoidal categories

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Ingredients of the Theory

To construct phase groups we need:

• Tensor products:

- Symmetric monoidal categories

• Unitarity:

- †-symmetric monoidal categories

• Observables:

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Ingredients of the Theory

To construct phase groups we need:

• Tensor products:

- Symmetric monoidal categories

• Unitarity:

- †-symmetric monoidal categories

• Observables:

- Special †-Frobenius algebras

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Ingredients of the Theory

To construct phase groups we need:

• Tensor products:

- Symmetric monoidal categories

• Unitarity:

- †-symmetric monoidal categories

• Observables:

- Special †-Frobenius algebras

This is a very general setting including much more than just quantum mechanics.

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Why Bother?

• Qubits, qutrits, etc

• Finite relations

• Toy models

• Convex operational theories

• Continuous variable QM

• Stab and Spek

• .....

What can phase groups say about quantum theory?

What can phase groups say about other theories?

QM

GNST

PRbox

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

DISCLAIMER

There are going to be a LOT of definitions in this talk.

sorry.

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Quantum Observables

What is “classical” anyway?

fundamental : incompatible observables* pos vs mom* X vs Z spins in fd

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Quantum Observables

What is “classical” anyway?

http://dresdencodak.com

fundamental : incompatible observables* pos vs mom* X vs Z spins in fd

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Observables

a0

a1

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Observables

a0

a1

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Observables

a0

a1

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Observables

a0

a1

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Observables

a0

a1

b1 b0

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Observables

a0

a1

b1 b0

**

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Observables

a0

a1

b1 b0

**

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Observables

a0

a1

b1 b0

**

|�ai | bj�| =1√D

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Observables

a0

a1

b1 b0

**

|�ai | bj�| =1√D

“Mutually Unbiased Bases”

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Z =�

1 00 −1

�X =

�0 11 0

X and Z Spins

α |0�+ β |1�

|0�✛

p=α2

|1�

✛p=

β2

|+�

p=

(α+

β)/

2 2✲

|−�

p=(α−

β)/2 2

We can measure the spin of qubit |ψ� = α |0� + β |1�

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Z =�

1 00 −1

�X =

�0 11 0

X and Z SpinsWe can measure the spin of qubit |ψ� = α |0� + β |1�

|0�

|0�✛

p=1

|1�

✛p=

0

|+�

p=

1/2

|−�

p=1/2

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Z =�

1 00 −1

�X =

�0 11 0

X and Z SpinsWe can measure the spin of qubit |ψ� = α |0� + β |1�

(|0�+ |1�)/√

2

|0�✛

p=1/

2

|1�

✛p=

1/2

|+�

p=

1✲

|−�

p=0

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

unless and are orthogonal [Wooters & Zurek 1982]

Theorem: There are no unitary operations D such that

D : |ψ� �→ |ψ� ⊗ |ψ�D : |φ� �→ |φ� ⊗ |φ�

No-Cloning and No-Deleting

unless and are orthogonal [Pati & Braunstein 2000]

Theorem: There are no unitary operations E such that

E : |ψ� �→ |0�E : |φ� �→ |0�

|ψ�

|ψ�

|φ�

|φ�

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

then the category collapses [Abramsky 2007]

Theorem: if a †-compact category has natural transformations

δ : − ⇒ −⊗−� : − ⇒ I

No-Cloning and No-Deleting, abstractly

(Translation: in our abstract setting there are no universal cloning or deleting operations, just like in quantum mechanics)

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

“Classical” Quantum States

When can a quantum state be treated as if classical?

• no-go theorems allow copying and deleting of orthogonal states;

In other words:

• A quantum state may be copied and deleted if it is an eigenstate of some known observable.

We’ll use this property to formalise observables in terms of copying and deleting operations.

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Classical Properties

In general, quantum observables are incompatible - not defined at the same time : position and momentum; X and Z spin; etc.

Traditional quantum logic constructs a property lattice for each set of compatible observables; the incompatible properties are simply incomparable in the lattice.

However if we want to compute with quantum mechanics we need to know how these observables relate to each other, i.e. how they interfere.

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Our Approach

We aim to extract the positive content from the incompatibility of quantum observables:

• basis of monoidal categories : no-cloning, no-deleting;

• observable structures : axiomatised in terms of a copying operation

• Phase groups : constructed from the observable structures

• incompatible observables : how do classical operations which act on complementary states interact?

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Monoidal Categories

A theory of interacting processes

f h

D

A

B

C

g k

C E

Ross Duncan ● Ottawa 2009

f : A→ B g : B → C h : C → D

A category consists of objects etc, and arrows between them:

Categories

A,B, C,

f gA

B

B

C

C

h

D

f : A→ B g : B → C h : C → D

Ross Duncan ● Ottawa 2009

A category consists of objects etc, and arrows between them:

Categories

A,B, C,

f

g

A

B

C

C

h

D

f : A→ B g : B → C h : C → D

g ◦ f : A → C

Ross Duncan ● Ottawa 2009

A category consists of objects etc, and arrows between them:

Categories

A,B, C,

f

g

A

B

C

h

D

h ◦ g ◦ f : A → D

Ross Duncan ● Ottawa 2009

A category consists of objects etc, and arrows between them:

Categories

A,B, C,

f

g

A

B

C

h

D

h ◦ g ◦ f : A → D

Ross Duncan ● Ottawa 2009

A category consists of objects etc, and arrows between them:

Categories

A,B, C,

f

g

A

B

C

h

D

h ◦ g ◦ f : A → D

Ross Duncan ● Ottawa 2009

A category consists of objects etc, and arrows between them:

Categories

A,B, C,

f

g

A

B

C

h

D

h ◦ g ◦ f : A → D

Ross Duncan ● Ottawa 2009

idA : A→ A

Categories

idA : A→ A

Ross Duncan ● Ottawa 2009

Categories

idA : A→ A

B

f

f ◦ idA : A → B

Ross Duncan ● Ottawa 2009

Categories

idA : A→ A

B

f

idB ◦ f : A → B

Ross Duncan ● Ottawa 2009

Categories

idA : A→ A

B

f

f : A→ B

Ross Duncan ● Ottawa 2009

f ⊗ h : A⊗ C → B ⊗D

The tensor is associative:

A strict monoidal category is a category equipped with a tensor product on both objects and arrows:

(f ⊗ g)⊗ h = f ⊗ (g ⊗ h)

Monoidal Categories

f h

D

A

B

C

gf

A

B

h

D

C

C

B

Ross Duncan ● Ottawa 2009

(g ◦ f)⊗ (k ◦ h) = (g ⊗ k) ◦ (f ⊗ h)

and identities:

The tensor product is bifunctorial, meaning that it preserves composition:

idA⊗B = idA ⊗ idB

Monoidal Categories

f h

D

A

B

C

g k

C E

A B

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

(idB ⊗ k) ◦ (f ⊗ idD) = (f ⊗ idE) ◦ (idA ⊗ k) = f ⊗ k

In particular we have the following:

Monoidal Categories

DA

B E

f

k

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

(idB ⊗ k) ◦ (f ⊗ idD) = (f ⊗ idE) ◦ (idA ⊗ k) = f ⊗ k

In particular we have the following:

Monoidal Categories

DA

B E

f

k

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

(idB ⊗ k) ◦ (f ⊗ idD) = (f ⊗ idE) ◦ (idA ⊗ k) = f ⊗ k

In particular we have the following:

Monoidal Categories

DA

B E

f k

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

j : A⊗B → C ⊗D ⊗ E

Of course, it’s quite possible to have arrows between tensors of objects which are not tensors themselves, e.g.

Monoidal Categories

D

A B

E

j

C

could be drawn like:

Ross Duncan ● Ottawa 2009

No lines are drawn for I in the graphical notation:

Monoidal categories have a special unit object called I which is a left and right identity for the tensor:

ψ : I → A φ† : A → I φ† ◦ ψ : I → I

I ⊗A = A = A⊗ I

idI ⊗ f = f = f ⊗ idI

Monoidal Categories

ψ : I → A φ† : A → I φ† ◦ ψ : I → Iψ : I → A φ† : A → I φ† ◦ ψ : I → I

ψ : I → A φ† : A → I φ† ◦ ψ : I → I

ψ : I → A φ† : A → I φ† ◦ ψ : I → I

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Any arrow can be multiplied by c using the tensor:

The arrows are called scalars and they enjoy some special properties:

c1 ⊗ c2 = c1 ◦ c2

c1 ⊗ c2 = c2 ⊗ c1

Monoidal Categories

c : I → I

fc

A

B

It doesn’t matter where c is drawn.

f : A→ B

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Any arrow can be multiplied by c using the tensor:

The arrows are called scalars and they enjoy some special properties:

c1 ⊗ c2 = c1 ◦ c2

c1 ⊗ c2 = c2 ⊗ c1

Monoidal Categories

c : I → I

fc

A

B

It doesn’t matter where c is drawn.

f : A→ B

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

σA,B : A⊗B → B ⊗A

Symmetric Monoidal Categories

A

B A

B

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

σA,B : A⊗B → B ⊗A

Symmetric Monoidal Categories

A B

A

B A

B

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

σA,B : A⊗B → B ⊗A

Symmetric Monoidal Categories

A B

A

B A

B

=

A

BA

B

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

σA,B : A⊗B → B ⊗A

Symmetric Monoidal Categories

A

B

Bgf

B

C

C

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

σA,B : A⊗B → B ⊗A

Symmetric Monoidal Categories

A

B

B

g f

B

C

C

Ross Duncan ● Ottawa 2009

A monoidal category is called †-monoidal if it is equipped with an involutive functor, which reverses the arrows while leaving the objects unchanged, which preserves the tensor structure.

f : A→ B f† : B → A

†-Monoidal Categories

(·)†

f

A

B A

Bf

Ross Duncan ● Ottawa 2009

An arrow is called unitary when:

†-Monoidal Categories

f : A→ B f† : B → A

(f ⊗ g)† = f† ⊗ g† σ†A,B = σB,A

BA

f

A

f

f

f

B

Ross Duncan ● Ottawa 2009

An arrow is called unitary when:

†-Monoidal Categories

f : A→ B f† : B → A

(f ⊗ g)† = f† ⊗ g† σ†A,B = σB,A

BA

A

f

f

B

Ross Duncan ● Ottawa 2009

An arrow is called unitary when:

†-Monoidal Categories

f : A→ B f† : B → A

(f ⊗ g)† = f† ⊗ g† σ†A,B = σB,A

BA

A B

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

The Category FDHilb

FDHilb is the category of finite dimensional complex Hilbert spaces. It is †-monoidal with the following structure.

• Objects: finite dimensional Hilbert spaces, etc

• Arrows: all linear maps

• Tensor: usual (Kronecker) tensor product;

• is the usual adjoint (conjugate transpose)

A linear map picks out exactly one vector. It is a ket and is the corresponding bra.

Hence is the inner product .

A,B, C,

I = Cf†

ψ : I → Aψ† : A→ I

ψ† ◦ φ : I → I �ψ | φ�

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: Preparing a Bell state

H

∧X

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

|0� : I → Q

Example: Preparing a Bell state

H

∧X

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

|0� : I → Q|0� : I → Q

Example: Preparing a Bell state

H

∧X

��10

�⊗

�10

��

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

|0� : I → Q|0� : I → Q

H : Q→ Q

Example: Preparing a Bell state

H

∧X

��10

�⊗

�10

���1√2

�1 00 1

�⊗

�1 11 −1

��·

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

|0� : I → Q|0� : I → Q

H : Q→ Q

∧X : Q⊗Q→ Q⊗Q

Example: Preparing a Bell state

H

∧X

��10

�⊗

�10

���1√2

�1 00 1

�⊗

�1 11 −1

��·

1 0 0 00 1 0 00 0 0 10 0 1 0

·

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

The Category FRel

FDHilb is the category of finite relations. It is †-monoidal with the following structure.

• Objects: finite sets, etc

• Arrows: Relations

• Tensor: Cartesian product;

• is relational converse:

A relation is simply a subset of X ; its converse is also a subset.

Hence is non-empty iff .

f†

R ⊆ X × Y

X, Y, Z,

X ⊗ Y := X × Y, I = {∗}(x, y) ∈ f ⇔ (y, x) ∈ f†

R ⊆ {∗}×X

S† ◦R : I → I R ∩ S �= ∅

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

d : I → A∗ ⊗A e : A⊗A∗ → I

Compact Closure

cut elimination in MLL proof nets

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

d : I → A∗ ⊗A e : A⊗A∗ → I

Compact Closure

cut elimination in MLL proof nets

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

d : I → A∗ ⊗A e : A⊗A∗ → I

Compact Closure

=

cut elimination in MLL proof nets

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Compact Structure of FDHilbIn FDHilb the compact structure is given by the maps:

whenever is a basis for and is the corresponding basis for the dual space

{ai}i {ai}iAA∗

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Compact Structure of FDHilbIn FDHilb the compact structure is given by the maps:

whenever is a basis for and is the corresponding basis for the dual space

d : 1 �→�

i

ai ⊗ ai e : ai ⊗ ai �→ 1

{ai}i {ai}iAA∗

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Compact Structure of FDHilbIn FDHilb the compact structure is given by the maps:

whenever is a basis for and is the corresponding basis for the dual space

|00�+ |11�√2

In the case of the map picks out the Bell state

which is the simplest example of quantum entanglement.

2 d

d : 1 �→�

i

ai ⊗ ai e : ai ⊗ ai �→ 1

{ai}i {ai}iAA∗

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: Quantum Teleportation

ψ : I → A φ† : A → I φ† ◦ ψ : I → I

Bob

Aleks

Bennett et al 1993; Abramsky & Coecke 2004

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: Quantum Teleportation

ψ : I → A φ† : A → I φ† ◦ ψ : I → I

Bob

Aleks|00�+ |11�√

2

Bennett et al 1993; Abramsky & Coecke 2004

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: Quantum Teleportation

ψ : I → A φ† : A → I φ† ◦ ψ : I → I

Bob

Aleks|00�+ |11�√

2

�00| + �11|√2

Bennett et al 1993; Abramsky & Coecke 2004

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: Quantum Teleportation

ψ : I → A φ† : A → I φ† ◦ ψ : I → I

Bob

Aleks

Bennett et al 1993; Abramsky & Coecke 2004

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: Quantum Teleportation

ψ : I → A φ† : A → I φ† ◦ ψ : I → I

Bob

Aleks

f

Bennett et al 1993; Abramsky & Coecke 2004

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: Quantum Teleportation

ψ : I → A φ† : A → I φ† ◦ ψ : I → I

Bob

Aleks

f

Bennett et al 1993; Abramsky & Coecke 2004

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: Quantum Teleportation

ψ : I → A φ† : A → I φ† ◦ ψ : I → I

Bob

Aleks

f

Bennett et al 1993; Abramsky & Coecke 2004

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: Quantum Teleportation

ψ : I → A φ† : A → I φ† ◦ ψ : I → I

Bob

Aleks

f†

f

Bennett et al 1993; Abramsky & Coecke 2004

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: Quantum Teleportation

ψ : I → A φ† : A → I φ† ◦ ψ : I → I

Bob

Aleks

Bennett et al 1993; Abramsky & Coecke 2004

Ross Duncan ● Ottawa 2009

Thm: one diagram can be deformed to another if and only if their denotations are equal by the structural equations of the category.

Graphical Calculus Theorem

f

hD

A

B

C

g

k

C

E

c

Ross Duncan ● Ottawa 2009

Thm: one diagram can be deformed to another if and only if their denotations are equal by the structural equations of the category.

Graphical Calculus Theorem

f

hD

A

B

C

g

k

C

E

c

= c

f

A

B

C

D

g

C

k

E

h

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Observable Structures

Copying, deleting, and all that

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Observable Structures

δ = δ† = �† =

=

=

Comonoid Laws

= =

� =

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Observable Structures

δ = δ† = �† =

=

=

= =

Monoid Laws

� =

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Observable Structures

δ = δ† = �† =� =

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Observable Structures

δ = δ† = �† =� =

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Observable Structures

δ = δ† = �† =

Frobenius LawIsometry Law

= = =

� =

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Observable Structures

Given any finite dimensional Hilbert space we can define an observable structure by

δ : A→ A⊗A :: ai �→ ai ⊗ ai

� : A→ I ::�

i

ai �→ 1

Example:

define a observable structure over qubits; the standard basis is copied and erased. Note however that:

δ : |0� �→ |00�|1� �→ |11� � : |0�+ |1� �→ 1

δ(|+�) = |00�+|11�√2

showing that not every state can be cloned.

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Observable Structures

Given any finite dimensional Hilbert space we can define an observable structure by

δ : A→ A⊗A :: ai �→ ai ⊗ ai

� : A→ I ::�

i

ai �→ 1

Example:

define a observable structure over qubits; the standard basis is copied and erased. Note however that:

δ : |0� �→ |00�|1� �→ |11� � : |0�+ |1� �→ 1

showing that not every state can be cloned.

=

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Observable Structures

Given any finite dimensional Hilbert space we can define an observable structure by

δ : A→ A⊗A :: ai �→ ai ⊗ ai

� : A→ I ::�

i

ai �→ 1

Theorem: in FDHilb, observable structures are in bijective correspondence to bases. [Coecke, Pavlovic, Vicary]

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Each (well behaved) observable defines a basis, hence each observable defines an observable structure!

Observable Structures

Given any finite dimensional Hilbert space we can define an observable structure by

δ : A→ A⊗A :: ai �→ ai ⊗ ai

� : A→ I ::�

i

ai �→ 1

Theorem: in FDHilb, observable structures are in bijective correspondence to bases. [Coecke, Pavlovic, Vicary]

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Classical Structure begets Compact Structure

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Frobenius Law

Classical Structure begets Compact Structure

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Classical Structure begets Compact Structure

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Unit Law

Unit Law

Classical Structure begets Compact Structure

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Classical Structure begets Compact Structure

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Classical Structure begets Compact Structure

==

Each classical structure induces a self-dual compact structure.

Self duality is addressed in Coecke, Paquette, & Perdrix 2008

Ross Duncan ● Ottawa 2009

Theorem: any maps constructed from δ and ε , and their adjoints, whose graph is connected, is determined uniquely by the number of inputs and outputs.

Spider Theorem

Coecke & Paquette 2006

Ross Duncan ● Ottawa 2009

Theorem: any maps constructed from δ and ε , and their adjoints, whose graph is connected, is determined uniquely by the number of inputs and outputs.

Spider Theorem

Coecke & Paquette 2006

Ross Duncan ● Ottawa 2009

Theorem: any maps constructed from δ and ε , and their adjoints, whose graph is connected, is determined uniquely by the number of inputs and outputs.

Spider Theorem

Coecke & Paquette 2006

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

α

Phase Maps

Spinning around an observable

Ross Duncan ● Ottawa 2009

Let be points of ; we can combine them using the monoid operation

Using the monoid operationψ, φ : I → A A

δ† : A⊗A→ A

ψ ⊙ φ := δ† ◦ (ψ ⊗ φ)

Ross Duncan ● Ottawa 2009

Let be points of ; we can combine them using the monoid operation

Using the monoid operationψ, φ : I → A A

δ† : A⊗A→ A

ψ ⊙ φ := δ† ◦ (ψ ⊗ φ)

θ

θ

Ross Duncan ● Ottawa 2009

Example: qubits

δ†Z : Q → Q⊗Q|i� → |i� ⊗ |i� |ψ� : I → Q

|φ� : I → Q

Ross Duncan ● Ottawa 2009

Example: qubits

δ†Z : Q → Q⊗Q|i� → |i� ⊗ |i�

δ†Z =�

1 0 0 00 0 0 1

�|ψ� : I → Q|φ� : I → Q

Ross Duncan ● Ottawa 2009

Example: qubits

δ†Z : Q → Q⊗Q|i� → |i� ⊗ |i�

δ†Z =�

1 0 0 00 0 0 1

|ψ� =�

ψ1

ψ2

|φ� =�

φ1

φ2

�|ψ� : I → Q|φ� : I → Q

Ross Duncan ● Ottawa 2009

Example: qubits

δ†Z : Q → Q⊗Q|i� → |i� ⊗ |i�

δ†Z =�

1 0 0 00 0 0 1

|ψ� ⊗ |φ� =

ψ1φ1

ψ1φ2

ψ2φ1

ψ2φ2

|ψ� : I → Q|φ� : I → Q

Ross Duncan ● Ottawa 2009

Example: qubits

δ†Z : Q → Q⊗Q|i� → |i� ⊗ |i� |ψ� : I → Q

|φ� : I → Q

|ψ� ⊙ |φ� := δ†Z ◦ (|ψ� ⊗ |φ�) =�

ψ1φ1

ψ2φ2

Ross Duncan ● Ottawa 2009

Moreover, each point can be lifted to an endomorphism

Using the monoid operationψ : I → A

Λ(ψ) : A→ A

Λ(ψ) := δ† ◦ (ψ ⊗ idA)

This yields a homomorphism of monoids so we have:

Ross Duncan ● Ottawa 2009

Example: qubits

δ†Z =�

1 0 0 00 0 0 1

�|ψ� =

�ψ1

ψ2

Ross Duncan ● Ottawa 2009

Example: qubits

δ†Z =�

1 0 0 00 0 0 1

�|ψ� =

�ψ1

ψ2

id⊗ |ψ� =

ψ1 0ψ1 00 ψ2

0 ψ2

Ross Duncan ● Ottawa 2009

Example: qubits

δ†Z =�

1 0 0 00 0 0 1

�|ψ� =

�ψ1

ψ2

id⊗ |ψ� =

ψ1 0ψ1 00 ψ2

0 ψ2

ΛZ(ψ) := δ†Z ◦ (id⊗ |ψ�) =�

ψ1 00 ψ2

Ross Duncan ● Ottawa 2009

Theorem: any maps constructed from δ, ε, some points and their adjoints, whose graph is connected, is determined by the number of inputs and outputs and the product .

Generalised Spider Theoremψi : I → A

�i ψi

Ross Duncan ● Ottawa 2009

Theorem: any maps constructed from δ, ε, some points and their adjoints, whose graph is connected, is determined by the number of inputs and outputs and the product .

Generalised Spider Theoremψi : I → A

�i ψi

φ

φ

Ross Duncan ● Ottawa 2009

Theorem: any maps constructed from δ, ε, some points and their adjoints, whose graph is connected, is determined by the number of inputs and outputs and the product .

Generalised Spider Theoremψi : I → A

�i ψi

Ross Duncan ● Ottawa 2009

A: In Hilbert spaces, is unitary iff is unbiased w.r.t. the basis copied by .

Q: When is unitary?

Unbiased Points

|ψ�Λ(ψ)δ

Ross Duncan ● Ottawa 2009

α

A: In Hilbert spaces, is unitary iff is unbiased w.r.t. the basis copied by .

Q: When is unitary?

Unbiased Points

|ψ�Λ(ψ)δ

α=

Ross Duncan ● Ottawa 2009

A: In Hilbert spaces, is unitary iff is unbiased w.r.t. the basis copied by .

Q: When is unitary?

Unbiased Points

|ψ�Λ(ψ)δ

α=

Ross Duncan ● Ottawa 2009

A: In Hilbert spaces, is unitary iff is unbiased w.r.t. the basis copied by .

Q: When is unitary?

Unbiased Points

|ψ�Λ(ψ)δ

= -α

Ross Duncan ● Ottawa 2009

Prop: 1. the unbiased points for form an abelian group w.r.t. to ;2. the arrows generated by the unbiased points form an abelian group w.r.t. composition.

⊙(δ, �)

A: In Hilbert spaces, is unitary iff is unbiased w.r.t. the basis copied by .

Q: When is unitary?

Unbiased Points

|ψ�Λ(ψ)δ

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qubits

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qubits

|0�

|1�

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qubits

π

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qubits

Unbiased pointsπ

|0� + eiα |1�

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qubits

Unbiased pointsπ

α

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qubits

Unbiased pointsπ

α

�1 00 eiα

�=

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qutrits

∆Z :|0� �→ |00�|1� �→ |11�|2� �→ |22� |0� + eiα |1� + eiβ |2�

1 0 00 eiα 00 0 eiβ

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qutrits

∆Z :|0� �→ |00�|1� �→ |11�|2� �→ |22� |0� + eiα |1� + eiβ |2�

Unbiased points

1 0 00 eiα 00 0 eiβ

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: FRel

D† : (x, x) ∼ x,∀x ∈ X

D† ◦ (id⊗ ψ) is unitary iff ψ = X

Hence the phase group is trivial.

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Observables

A very general theory of interference

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Two kinds of points

δ = δ† = �† =� =

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Two kinds of points

δ = δ† = �† =

Classical Points

� =

i

Those points which can be copied by δ

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Two kinds of points

δ = δ† = �† =

Classical Points

� =

i= i i

Those points which can be copied by δ

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

* to keep the pictures tidy, a scalar factor has been omitted (and everywhere

from here on)

Two kinds of points

δ = δ† = �† =

Classical Points

� =

i= i i

Those points which can be copied by δ

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Two kinds of points

δ = δ† = �† =

Unbiased PointsClassical Points

� =

i= i i

Those points which can be copied by δ

α

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Two kinds of points

δ = δ† = �† =

Unbiased PointsClassical Points

� =

i= i i

Those points which can be copied by δ

α

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Two kinds of points

δ = δ† = �† =

Unbiased PointsClassical Points

� =

i= i i

Those points which can be copied by δ

=

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Classical Structures

δX = �X =δZ = �Z =

|i� �→ |ii� |±� �→ |±±�|+� �→ 1 |0� �→ 1

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

i= i i ⇒

i

i=

Complementary Classical Structures

δX = �X =δZ = �Z =

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

i= ⇒

i

i=i i

Complementary Classical Structures

δX = �X =δZ = �Z =

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Classical Structures

δX = �X =δZ = �Z =

= =

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Classical Structures

Classical points

Unbiased pointsπ

π

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Classical Structures

Classical points

Unbiased pointsπ

π!

|0� =

|1� =

�1 00 eiα

�=!

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Classical Structures

Classical points

Unbiased pointsπ

π!

|0� =

|1� =

�1 00 eiα

�=!

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Classical Structures

Classical points

Unbiased pointsπ

π!

|0� =

|1� =

�1 00 eiα

�=!

=�

cos α2 i sin α

2i sin α

2 cos α2

�! !

|+� =

|−� =

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qutrits

∆Z :|0� �→ |00�|1� �→ |11�|2� �→ |22�

1 0 00 eiα 00 0 eiβ

∆X :|+� �→ |++�|ω� �→ |ωω�|ω� �→ |ωω�

1 + eiα + eiβ 1 + ωeiα + ωeiβ 1 + ωeiα + ωeiβ

1 + ωeiα + ωeiβ 1 + eiα + eiβ 1 + ωeiα + ωeiβ

1 + ωeiα + ωeiβ 1 + ωeiα + ωeiβ 1 + eiα + eiβ

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Classical points are eigenvectors

αi

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Classical points are eigenvectors

α i

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Classical points are eigenvectors

α ii

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Closedness Property

δX = �X =δZ = �Z =

Defn: complentary classical structures are called closed when...

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Closedness Property

δX = �X =δZ = �Z =

⇒i

= i i

j= j j

=i⊙ j i⊙ j i⊙ j

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Closedness Property

δX = �X =δZ = �Z =

⇒i

= i i

j= j j

=i⊙ j i⊙ j i⊙ j

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Closedness Property

δX = �X =δZ = �Z =

In fdHilb it is always possible to construct a pair of mutually unbiased bases with this property...

... but in big enough dimension, it is possible to construct MUBs which are not closed.

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Classical Points form a Subgroup

By the defn of complementarity, we have that:

PROP: If the observable structure is closed, and there are finitely many classical points, then they form a subgroup of the unbiased points, i.e.

In particular, each is a permutation on .

CX ⊆ UZ

CZ ⊆ UX

(CZ ,⊙X) ≤ (UX ,⊙X)(CX ,⊙Z) ≤ (UZ ,⊙Z)

ΛX(zi) CZ

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Classical Structures

Classical points

Unbiased pointsπ

π!

|0� =

|1� ==

�1 00 eiα

�!

=�

cos α2 i sin α

2i sin α

2 cos α2

�! !

|+� =

|−� =

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Complementary Classical Structures

Classical points

Unbiased pointsπ

π!

|0� =

|1� ==

= !

|+� =

|−� =

�0 11 0

�!

�1 00 −1

�!

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

The Following are Equivalent:

δX = �X =δZ = �Z =

⇒i

=i i

j

=j j =

i⊙ j i⊙ j i⊙ j

⇒i

=i i

j

=j j =

i⊙ j i⊙ j i⊙ j

1. The classical structures are

closed

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

The Following are Equivalent:

ii

δX = �X =δZ = �Z =

2. The classical maps are comonoid

homomorphisms

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

The Following are Equivalent:

i i

δX = �X =δZ = �Z =

2. The classical maps are comonoid

homomorphisms

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

The Following are Equivalent:

δX = �X =δZ = �Z =

3. The classical maps satisfy canonical

commutation relations

ij i

j ij

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

The Following are Equivalent:

δX = �X =δZ = �Z =

4. The classical structures form a

bialgebra

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Automorphism Action

Theorem: The classical maps are group automorphisms of the unbiased points:

αii

action of red points copied by green on the green phase group

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Automorphism Action

Theorem: The classical maps are group automorphisms of the unbiased points:

α

-i-i

ii

action of red points copied by green on the green phase group

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Automorphism Action

Theorem: The classical maps are group automorphisms of the unbiased points:

α

-i-i

i

i

action of red points copied by green on the green phase group

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Automorphism Action

Theorem: The classical maps are group automorphisms of the unbiased points:

α

-i

i

action of red points copied by green on the green phase group

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Automorphism Action

Theorem: The classical maps are group automorphisms of the unbiased points:

-i

i

action of red points copied by green on the green phase group

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Automorphism Action

Theorem: The classical maps are group automorphisms of the unbiased points:

action of red points copied by green on the green phase group

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Automorphism Action

Theorem: The classical maps are group automorphisms of the unbiased points:

action of red points copied by green on the green phase group

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Automorphism Action

Theorem: The classical maps are group automorphisms of the unbiased points:

action of red points copied by green on the green phase group

!! !!

! !!

!!

! ! !! !

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Automorphism Action

Theorem: The classical maps are group automorphisms of the unbiased points:

Classical points are symmetries of the phase group.

action of red points copied by green on the green phase group

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qutrits

∆Z :|0� �→ |00�|1� �→ |11�|2� �→ |22�

1 0 00 eiα 00 0 eiβ

∆X :|+� �→ |++�|ω� �→ |ωω�|ω� �→ |ωω�

1 + eiα + eiβ 1 + ωeiα + ωeiβ 1 + ωeiα + ωeiβ

1 + ωeiα + ωeiβ 1 + eiα + eiβ 1 + ωeiα + ωeiβ

1 + ωeiα + ωeiβ 1 + ωeiα + ωeiβ 1 + eiα + eiβ

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qutrits

∆Z :|0� �→ |00�|1� �→ |11�|2� �→ |22�

1 0 00 eiα 00 0 eiβ

∆X :|+� �→ |++�|ω� �→ |ωω�|ω� �→ |ωω�

1 + eiα + eiβ 1 + ωeiα + ωeiβ 1 + ωeiα + ωeiβ

1 + ωeiα + ωeiβ 1 + eiα + eiβ 1 + ωeiα + ωeiβ

1 + ωeiα + ωeiβ 1 + ωeiα + ωeiβ 1 + eiα + eiβ

Phase maps are classical when:

α ∈ {0,π

3,2π

3} β = 2π − α

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qutrits

CZ = {

1 0 00 1 00 0 1

,

0 1 00 0 11 0 0

,

0 0 11 0 00 1 0

}

CX = {

1 0 00 1 00 0 1

,

1 0 00 ω 00 0 ω

,

1 0 00 ω 00 0 ω

}

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qutrits

CZ = {

1 0 00 1 00 0 1

,

0 1 00 0 11 0 0

,

0 0 11 0 00 1 0

}

CX = {

1 0 00 1 00 0 1

,

1 0 00 ω 00 0 ω

,

1 0 00 ω 00 0 ω

}

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qutrits

0 1 00 0 11 0 0

·

1

eiα

eiβ

=

eiα

eiβ

1

1

ei(β−α)

e−iβ

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qutrits

0 1 00 0 11 0 0

·

1

eiα

eiβ

=

eiα

eiβ

1

1

ei(β−α)

e−iβ

(α, β) �→ (β − α,−α)

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qutrits

0 1 00 0 11 0 0

·

1

eiα

eiβ

=

eiα

eiβ

1

1

ei(β−α)

e−iβ

(α, β) �→ (β − α,−α)

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Example: qutrits

0 1 00 0 11 0 0

·

1

eiα

eiβ

=

eiα

eiβ

1

1

ei(β−α)

e−iβ

(α, β) �→ (β − α,−α)

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Conclusions

We formalised complementary quantum observables in the language of monoidal categories:

• each observable defines two groups: its classical points and its unbiased points

• Interference between pairs of complementary observables is characterised via a group of automorphisms

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Ongoing work 1

Current research directions:

• Investigate connections with multipartite entanglement (with Bill Edwards)

• Algorithmic properties of MBQC (with Simon Perdrix)

• Study toy models of QM based on the automorphism approach.

• Use phase groups to construct MUBs

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Ongoing work 2

Collaborating with Lucas Dixon (Edinburgh) and Aleks Kissinger (Oxford) to automate this calculus using a graphical rewriting system / interactive theorem prover.

- Rewriting properties e.g. normal forms?

- Pattern languages: ellipses and indexed containers?

http://dream.inf.ed.ac.uk/projects/quantomatic/

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

I cited results by these people:

Bob Coecke Samson Abramsky

Dusko Pavlovic

Eric PaquetteSimon Perdrix

Peter Selinger... and Jamie Vicary Use it: http://arxiv.org

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Reference

B. Coecke and R. Duncan, Interacting Quantum Observables, Proceedings of ICALP, 2008

(Long version going onto arxiv.org as soon as we can get the 100s of diagrams past their TeX robot....maybe later today)

Ross Duncan ● Categories Quanta & Concepts ● Perimeter Institute 2009

Reference

B. Coecke and R. Duncan, Interacting Quantum Observables, Proceedings of ICALP, 2008

(Long version going onto arxiv.org as soon as we can get the 100s of diagrams past their TeX robot....maybe later today)

Thanks!