Physlib.Particles.SuperSymmetry.N1.Basic
SUSY N=1 chiral sector: index, configuration, and conjugation data
i. Overview
This file fixes the data that indexes the scalars of the N=1 chiral sector, makes their contractions type-safe, and equips them with conjugation.
A single finite type `ι` indexes the chiral scalars (written `ChiralIndexingType` in signatures) — the only index type. Variance (upper versus lower) and holomorphy (a scalar versus its complex conjugate) are not separate index types but the two axes of a four-element type `ChiralColor`, the product of `chiral`/`anti` with `up`/`down`. Each axis is realized as a genuine carrier distinction, not a label: variance as a module versus its dual (`ι → ℂ` versus `Module.Dual ℂ (ι → ℂ)`), holomorphy as a module versus its complex conjugate (`ConjModule`, where `i` acts as `−i`).
The dual-colour involution `τ` flips variance and preserves holomorphy. Two indices may contract exactly when their colours are `τ`-related, so a holomorphic index pairs only with a holomorphic index of the opposite variance, and a conjugate ("barred") index only with a conjugate index of the opposite variance. This is the discipline that makes the F-term contraction `g^{IJ̄} D_I W D̄_J̄ W̄` type-check.
The physical field content is the configuration `ChiralScalarConfiguration ι = ι → ℂ`, carrying `2 · Fintype.card ι` real degrees of freedom. The anti-chiral scalars are the complex conjugates of this data, never an independent configuration.
The index data is packaged as a `ConjTensorSpecies` over `ChiralColor`, each colour carrying its distinct carrier from above. Complex conjugation is the conjugate-linear identity `conjEquiv : M ≃ₛₗ[starRingEnd ℂ] ConjModule M` on each carrier (anti basis `Basis.conj`); the species' holomorphy flip (`conjEquiv`, hence `conjT`) is built from it. Every colour carries the trivial representation over the trivial group `Unit`, so the chiral scalars hold no charge. Contracting a colour against its `τ`-dual is the dot product of the two coordinate vectors, the Kronecker `δ_{IJ}` on basis labels: `contr` is that pairing `V c ⊗ V (τ c) → ℂ`, `unit` its cap in `V (τ c) ⊗ V c`, and `metric` the cap `∑_I b_I ⊗ b_I` in `V c ⊗ V c`. This instance equips the chiral sector with the framework's generic tensor API (`.Tensor`, `.contrT`, …).
Conjugation is intrinsic species data: a `ConjTensorSpecies` is a `TensorSpecies` extended with the conjugate-colour involution `ChiralColor.bar` and its coherence. The framework then supplies the map `conjT` (conjugate the components and flip each index's holomorphy by `bar`) and its laws. `bar` is the holomorphy dual, distinct from and commuting with the variance dual `τ`; it is not used in contraction.
Conjugation enters wherever reality does. It is what lets one state that the Kähler metric is Hermitian (`conjT g` equals `g` with its two indices swapped), that the anti-chiral sector is the complex conjugate of the chiral one (`D̄_J̄ W̄ = conjT (D_I W)`), and hence that the F-term `g^{IJ̄} D_I W D̄_J̄ W̄` is real. The species can express none of these alone.
ii. Key results
- `SUSY.N1.ChiralScalarConfiguration` : the scalar configuration space `ι → ℂ`, where `ι` is the finite type indexing the chiral scalars. This is the only field data in the sector. - `SUSY.N1.ChiralColor` : the four colours `chiral`/`anti` × `up`/`down`, with the dual-colour involution `ChiralColor.tau`. - `SUSY.N1.chiralTensor` : the `ConjTensorSpecies` assembled from the above, whose `τ`-discipline makes the F-term contraction type-safe and whose `bar` carries the chiral-antichiral conjugation in which reality and Hermiticity conditions are phrased.
iii. Table of contents
- A. The chiral scalar configuration
- B. The chiral colours and the dual involution
- C. Carrier, representation, and basis
- D. The δ structure on based finite modules
- E. The chiral-index tensor species
- F. Conjugation
iv. References
A. The chiral scalar configuration
B. The chiral colours and the dual involution
C. Carrier, representation, and basis
A `TensorSpecies` takes, for each colour `c`, a carrier module, a group representation on it, and a basis. The carrier depends on *both* axes: variance gives the vector/dual distinction (`ι → ℂ` versus `Module.Dual ℂ (ι → ℂ)`) and holomorphy the conjugate-module distinction (`ConjModule …`, where `i` acts as `−i`), so all four colours have distinct carriers. The representation is trivial over the trivial group `Unit` (no charge) for every colour; each basis is indexed by `ι` — `piBasis`, its dual `piBasis.dualBasis`, and the `Basis.conj` of each. Variance (`τ`) sends a carrier to its dual; conjugation (`bar`) sends it to its conjugate module.
D. The δ structure on based finite modules
The contraction, unit, and metric are one δ structure in basis coordinates. Here `metric` is the `TensorSpecies` field of that name — the δ index-raising tensor `δ^{IJ}` — and is *not* the physical Kähler metric `g_{IJ̄}`, which is built downstream on top of this sector. A contraction pairs a colour with its variance dual `τ c`, whose carriers are *distinct* (a module and its dual, or their conjugates) but share the index `ι`, so the pairing is the dot product *across two based modules* `(M, b)` and `(N, b')`, `(x, y) ↦ ∑_I (b x)_I (b' y)_I`, with cap `∑_I b_I ⊗ b'_I ∈ M ⊗ N`. The single-colour cap `deltaCap` (`b = b'`) is what `metric c` uses, since its two slots are the same colour; the two-module pairing `deltaContr₂`/`deltaCap₂` is what `contr` and `unit` use. The δ data stays within one holomorphy and needs no conjugation; conjugation is carried instead by the tensor `conjT` (§F).
E. The chiral-index tensor species
F. Conjugation
Reality is a physical input the bare species cannot express: that the anti-chiral fields are the complex conjugates of the chiral ones, that the Kähler metric is Hermitian, that the F-term potential is real. Each is a statement that some quantity equals its own conjugate, so it can only be phrased once conjugation is available. This section exposes that operation for the two shapes the sector actually conjugates — the scalar `W` and the holomorphic covector `D_I W` — and certifies on components that it is honest complex conjugation.
Conjugation is bundled into `chiralTensor` itself (§E): as a `ConjTensorSpecies` it carries `bar` beside `τ`, and the framework supplies the conjugation map `conjT` and its laws (`conjT_smul`, `conjT_conjT`, `conjT_contrT`, `conjT_eq_permT_iff`) once, abstractly, against any `ConjTensorSpecies`. The chiral sector's conjugation flips holomorphy (`ChiralColor.bar`) while preserving variance, and through `chiralTensor.conjT` the reality and Hermiticity conditions are phrased. The basis index type `ι` is the same for every colour, so the identification `barIdx_eq` is `rfl` and the component reindexing is the identity.
The following normalize the output of `(chiralTensor (ι := ι)).conjT` back to the canonical colour lists for scalar and anti-holomorphic covector tensors respectively.
33 declarations
Chiral scalar configuration
Given a type representing the indices of chiral scalars, a **chiral scalar configuration** is defined as the space of functions . This configuration assigns a complex value to each chiral label and represents the physical field data of the sector.
The four-element set of index colors
The inductive type represents the four possible states for an index in the chiral sector. It is defined as the product of two axes: 1. **Holomorphy**: Distinguishes between chiral (holomorphic) and anti-chiral (anti-holomorphic/complex conjugate) components. 2. **Variance**: Distinguishes between "up" (contravariant) and "down" (covariant) indices, representing the distinction between a module and its dual. Together, these axes allow a single index type to label the physical scalar fields and their conjugates across different tensor configurations.
Equality on is decidable
The equality of index colors in the set is decidable. This means that for any two colors , there is an algorithmic procedure to determine whether or .
The dual-color involution on
The dual-color involution maps an index color to its variance dual while preserving its holomorphy. Specifically, it swaps "up" (contravariant) and "down" (covariant) labels as follows: \begin{itemize} \item \item \item \item \end{itemize} In the chiral sector, two indices are eligible for contraction if and only if their colors are -related, ensuring that a holomorphic vector index pairs only with a holomorphic dual index , and similarly for anti-holomorphic indices.
Complex conjugation of a
The function defines the complex conjugation operation on the index colors of the chiral sector. It interchanges the holomorphy states (mapping "chiral" to "anti" and vice versa) while preserving the variance of the index ("up" or "down"). Specifically, the mapping is defined as follows: - - - -
for all
For any index color in the chiral sector, the complex conjugation operation is an involution, meaning that applying it twice returns the original color: .
Complex Conjugation and Dual-Color Involution Commute ()
For any index color in the chiral sector, the complex conjugation operation and the dual-color involution commute. That is, where inter-converts chiral and anti-chiral labels while preserving variance, and inter-converts up and down labels while preserving holomorphy.
Carrier module for index color
For a finite set indexing the chiral fields, let be the space of complex-valued functions on . The function assigns to each color a corresponding carrier module (a complex vector space) according to its holomorphy and variance: - If , the module is . - If , the module is the dual space . - If , the module is the conjugate module , where scalar multiplication is defined as . - If , the module is the conjugate of the dual space .
Additive commutative group structure for each carrier module
For each color , the corresponding carrier module —which represents the space of chiral scalars , its dual space , or their respective complex conjugate modules—is equipped with an additive commutative group structure.
-module structure on
For each index color , the corresponding carrier space is equipped with a -module structure. This provides a complex vector space structure for all four possible index types: the chiral vector space , its dual space , and their respective complex conjugate modules.
is the trivial representation of on
For each color , the function defines the trivial representation of the trivial group on the corresponding complex carrier module . This implies that the chiral scalar fields carry no charge under this group action.
Standard basis for
Given a finite indexing type , the standard basis for the space of functions is the collection of indicator functions , where for . In the context of the supersymmetric chiral sector, this basis represents the standard basis for the vector carrier (the "chiral up" indices) and serves as the reference basis for the pairing and tensor contractions.
Standard bases for the chiral carrier modules
For each color , the function defines a basis indexed by the finite set for the corresponding carrier module . Let be the space of complex-valued functions on with its standard basis (where ), and let be its dual space with the dual basis . The basis is assigned as follows: - For , the basis is the standard basis of the holomorphic vector space . - For , the basis is the dual basis of the holomorphic covector space . - For , the basis is the conjugate basis of the anti-holomorphic vector space (the conjugate module ). - For , the basis is the conjugate of the dual basis of the anti-holomorphic covector space (the conjugate module ).
The cap tensor
Given a complex module with a basis indexed by a finite type , the cap is the rank-2 tensor in defined by the sum . This element represents a tensor with components in the basis , serving as an inverse-metric or "cap" for index contraction.
-bilinear pairing between based modules and
Given vector spaces and over with bases and indexed by a finite set , the function is the bilinear map defined by the dot product of the coordinate vectors. For vectors and , the pairing is given by: where and are the coordinates of and with respect to the bases and respectively. This is constructed by identifying with and using the canonical isomorphism between and its dual space induced by the basis .
Let and be complex vector spaces with bases and indexed by a finite set . For any vectors and , the -bilinear pairing evaluated at is the dot product of their coordinates: where and denote the -th coordinates of and with respect to the bases and , respectively.
-contraction for based modules
Given vector spaces and over equipped with bases and indexed by a finite set , the function is the linear map that performs a -contraction between the two modules. For any pure tensor , the map is defined by the dot product of their coordinate vectors: where and are the coordinates of and with respect to the bases and , respectively. This map is obtained by lifting the bilinear pairing to the tensor product.
Let and be complex vector spaces equipped with bases and indexed by a finite set . For any vectors and , the -contraction map evaluated on the pure tensor is given by the dot product of their coordinates: where and denote the -th coordinates of and with respect to the bases and , respectively.
Let and be vector spaces over equipped with bases and respectively, where is a finite indexing set. For any vector and any index , the -contraction of the pure tensor in satisfies where denotes the -th coordinate of the vector with respect to the basis .
Given complex vector spaces and equipped with bases and indexed by a set , the -contraction of the basis elements and is given by the Kronecker delta: where equals if and otherwise. This result expresses that the two bases are -dual under the contraction map.
Symmetry of the two-module -contraction under factor swapping
Let be a finite index set. Let and be complex vector spaces equipped with bases and , respectively. For any vectors and , the -contraction of the tensor product with respect to the pair of bases is equal to the -contraction of the swapped tensor product with respect to the swapped pair of bases : where is defined by the sum of the products of the components of the vectors in their respective bases.
Two-module -cap
Let be a finite index set. Given a basis for a complex vector space and a basis for a complex vector space , the two-module -cap is the element of the tensor product defined by the sum: where and are the basis elements corresponding to the index .
Symmetry of the two-module -cap under factor swapping
Let be a finite index set. Let and be complex vector spaces equipped with bases and , respectively. The two-module -cap is defined as the element in the tensor product . This theorem states that the image of the -cap formed by under the canonical swapping isomorphism (where ) is the -cap formed by the bases in reverse order :
Symmetry of the two-module -cap under factor swapping
Let be a finite index set. Let and be complex vector spaces equipped with bases and respectively. The two-module -cap is defined as the element in the tensor product . This theorem states that the -cap formed by the bases in reverse order is equal to the image of the -cap formed by under the canonical swapping isomorphism : where .
Snake Identity: Contracting with the Two-Module -Cap Returns
Let be a finite index set. Let and be complex vector spaces equipped with bases and , respectively. Let be the two-module -cap and be the -contraction map defined by the pairing of coordinates . For any vector , the snake identity holds: where is the canonical associativity isomorphism and is the left unit isomorphism . In physical terms, this states that contracting a field into one leg of the -cap returns the field .
Contraction of inner legs of equals
Let be a finite index set, and let and be complex vector spaces equipped with bases and , respectively. Consider the -cap tensors and . The contraction of the second leg of with the first leg of using the -contraction map (which maps to ) results in the two-module -cap in :
Chiral Sector Tensor Species with Conjugation
Let be a finite index set. The `chiralTensor` is the conjugate tensor species (`ConjTensorSpecies`) for the SUSY chiral sector over the field . It organizes the vector spaces, representations, and contractions for the scalar fields and their conjugates. The structure is defined by the following components: 1. **Index Colors and Carriers**: The colors represent the four combinations of holomorphy (chiral/anti-chiral) and variance (up/down). To each color , it assigns a carrier module (which are the spaces , its dual , or their complex conjugates) equipped with a basis indexed by . 2. **Group Action**: The symmetry group is the trivial group , which acts via the trivial representation on every carrier module. 3. **Contraction and Metric**: * The dual-color involution swaps the variance (up down) while preserving holomorphy. * The contraction is the -pairing of the two bases: . * The unit and the metric are both defined as the -cap tensor: . 4. **Conjugation**: The conjugation involution swaps the holomorphy (chiral anti-chiral) while preserving variance. Since all bases are indexed by the same set , the identification between index sets of conjugated colors is the identity. The contraction maps are real in the sense that they commute with complex conjugation ().
Conjugation of a scalar tensor
For a scalar tensor (a rank-0 tensor with an empty list of indices ) in the chiral sector, this function computes its conjugate. It applies the general species conjugation and uses the identity permutation to normalize the resulting color list back to the canonical empty list. Physically, this corresponds to the complex conjugation of a scalar field.
Conjugation of a holomorphic covector
For a finite index set , let be a holomorphic covector in the chiral sector, represented as a tensor of rank 1 with the color sequence . The function `conjChiralCovector` maps to its conjugate anti-holomorphic covector with color sequence . If has components with respect to the holomorphic basis , then the resulting tensor has components with respect to the conjugate basis .
For any rank-0 tensor (scalar) in the SUSY chiral sector, let be its corresponding scalar value. The scalar value of the conjugated tensor is equal to the complex conjugate of the scalar value of : where the overbar denotes the complex conjugate (the `star` operation in ).
Components of are
For a finite index set in the chiral sector, let be a holomorphic covector (a tensor of rank 1 with color `chiralDown`). For any index , the component of the conjugate anti-holomorphic covector corresponding to is the complex conjugate of the -th component of : where the components are taken with respect to the canonical bases for the respective tensor spaces.
Additivity of Chiral Covector Conjugation
For any two holomorphic covectors and in the chiral sector (tensors of rank 1 with color ), the conjugation map is additive: where the resulting tensors are anti-holomorphic covectors with color .
For any complex scalar and any holomorphic covector in the chiral sector (a tensor of rank 1 with color sequence ), the conjugation operation is conjugate-linear with respect to scalar multiplication: where denotes the complex conjugate of .
