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Lie theory · Group

SU(3)\mathrm{SU}(3)Special unitary group

The simply connected compact group of type A₂. Highest weights have two nonnegative Dynkin labels (p, q).

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Executable coverageGauge theoryColor
Definition

3 × 3 complex unitary matrices of determinant 1

Definition sources
Real dimension
88
Source and assumptions
Center
Z3\mathbb Z_{3}
Source and assumptions
Fundamental group
00
Source and assumptions

Reference properties

PropertyValueEvidence
Real dimension88Sources
CenterZ3\mathbb Z_{3}Sources
Fundamental group00Sources
CompactYesSources
ConnectedYesSources
Rank22Sources

Representations

An irrep (p,q) has dimension (p+1)(q+1)(p+q+2)/2 and center charge p+2q modulo 3. [sources]

Topology and global form

SU(3) is simply connected; its center is generated by exp(2πi/3)I. The adjoint form is PSU(3). [sources]

In physics

Color symmetry, multiplet decompositions, weight diagrams, and global gauge structure. [sources]

A₂ Dynkin-label convention

The labels (p,q) mean λ = pω₁ + qω₂, with (1,0) the defining 3 and (0,1) its conjugate. The scalar center generator exp(2πi/3)I acts with charge p + 2q modulo 3. [sources]

The Weyl dimension product over α₁, α₂, and α₁+α₂ gives dim(p,q) = (p+1)(q+1)(p+q+2)/2. [sources]

Related objects and maps

Claims and sources

Each assertion has a stable identifier within this record and a source locator or derivation. Cite the dataset edition when referring to a corrected or historical claim.

Definition

3 × 3 complex unitary matrices of determinant 1

group:su-3#definition
Real dimension

8

group:su-3#dimension
Center

ℤ₃

group:su-3#center
Fundamental group

0

group:su-3#pi1
Compact

Yes

group:su-3#compact
Connected

Yes

group:su-3#connected
Rank

2

group:su-3#rank
Representations

An irrep (p,q) has dimension (p+1)(q+1)(p+q+2)/2 and center charge p+2q modulo 3.

group:su-3#representations-1
Topology and global form

SU(3) is simply connected; its center is generated by exp(2πi/3)I. The adjoint form is PSU(3).

group:su-3#topology-1
In physics

Color symmetry, multiplet decompositions, weight diagrams, and global gauge structure.

group:su-3#physics-1
A₂ Dynkin-label convention

The labels (p,q) mean λ = pω₁ + qω₂, with (1,0) the defining 3 and (0,1) its conjugate. The scalar center generator exp(2πi/3)I acts with charge p + 2q modulo 3.

Derivation: The defining module has charge 1 and its exterior square has charge 2; highest-weight charges add.

Premises: Fundamental modules C³ and Λ²C³ · Dynkin labels p,q

group:su-3#weight-convention-1
A₂ Dynkin-label convention

The Weyl dimension product over α₁, α₂, and α₁+α₂ gives dim(p,q) = (p+1)(q+1)(p+q+2)/2.

Derivation: Apply the Weyl dimension formula to the three positive roots of A₂.

Premises: λ=pω₁+qω₂ · ρ=ω₁+ω₂ · Positive-root coroot pairings with ρ are 1,1,2

group:su-3#weight-convention-2
Related group

group:psu-3

group:su-3#relation-1
Related group

group:su-2

group:su-3#relation-2
Actual real Lie algebra

algebra:su-3-r

group:su-3#relation-3
Real-form context

real-form:su-3-r

group:su-3#relation-4
Explicit homomorphism

map:su-3-to-psu-3

group:su-3#relation-5
Explicit homomorphism

map:su-2-to-su-3-regular

group:su-3#relation-6
Explicit homomorphism

map:su-2-to-su-3-principal

group:su-3#relation-7