A one-sided ancilla, and the fixed-state dilation in a bipartite model #
Introspection's adaptive inductions replace a measurement of the first player by a projective one
acting on the old space and a fresh ancilla, prepared in one fixed state for every question
(MIPRE.Introspection.extVecA in the matrix analysis). In a bipartite model
(Phase 4 of planning/mipco-track.md):
- The one-sided extension
BipartiteModel.expandA M t₀: the first player's registerT, in the basis statet₀; the first player's algebra becomes theT × Tmatrices over𝒜, the second player's is unchanged, acting as1 ⊗ b. The state isM.ψ ⊗ e_{t₀}(OperatorMatrix.emb), so a quadratic form, a Born probability or a squared state norm on the extension is the one of the(t₀, t₀)entry, or of thet₀-th column (qform_expandA,bornProb_expandA,stateSqNorm_expandA). - The inert embedding
BipartiteModel.inertA M t₀, a local isometryM → M.expandA t₀carrying the state to the state, with the first player's operatorabecominga ⊗ 1. - Local isometries extend along registers (
LocalIsometry.expand), so the inert embedding of the ancilla is one of the register models too.
The fixed-state dilation itself is MIPRE.exists_pvm_dilation
(MIPRE/Foundations/KrausDilation.lean), in the first player's algebra.
The constant diagonal X ↦ X ⊗ 1, as a unital ⋆-homomorphism.
Equations
- MIPRE.diagStarAlgHom = { toFun := fun (X : R) => Matrix.diagonal fun (x : α) => X, map_one' := ⋯, map_mul' := ⋯, map_zero' := ⋯, map_add' := ⋯, commutes' := ⋯, map_star' := ⋯ }
Instances For
The one-sided ancilla extension: a register T for the first player only, in the basis
state t₀. The space is H ⊗ ℂ^T, the state ψ ⊗ e_{t₀}, the first player's operators the
T × T matrices over 𝒜, and the second player's b acts as 1 ⊗ b.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The norm of the extended state is the norm of the state.
An operator matrix on an embedded vector: its t₀-th column.
The quadratic form of the extension is that of the (t₀, t₀) entry.
The squared state norm of the extension is that of the t₀-th column.
A Born probability on the extension is that of the (t₀, t₀) entry.
The first player's squared state norm on the extension: that of the t₀-th column.
Components #
The Hilbert space of a one-sided extension is the ℓ² sum.
Equations
- M.amplA t₀ = LinearIsometryEquiv.refl ℂ (MIPRE.OperatorMatrix.Ampl T M.H)
Instances For
Two vectors of a one-sided extension are equal if their components are.
The inert embedding #
The inert embedding of a model into its one-sided extension: the state goes to
ψ ⊗ e_{t₀}, the first player's operator a to a ⊗ 1, the second player's are unchanged.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Local isometries extend along registers #
A linear isometry applied in each component of an ℓ² sum.
Equations
- MIPRE.BipartiteModel.amplMap W = { toFun := fun (v : MIPRE.OperatorMatrix.Ampl ι H) => WithLp.toLp 2 fun (i : ι) => W (v.ofLp i), map_add' := ⋯, map_smul' := ⋯, norm_map' := ⋯ }
Instances For
The isometry of the extensions by the same register, componentwise.
Equations
- Φ.expandW e = (M'.ampl e).symm.toLinearIsometry.comp ((MIPRE.BipartiteModel.amplMap Φ.W).comp (M.ampl e).toLinearIsometry)
Instances For
A local isometry extends along a register: the extensions of the two models by the same registers in the same state, with the players' block matrices mapped entrywise.
Equations
- Φ.expand e = { W := Φ.expandW e, ΦA := MIPRE.BipartiteModel.mapMatrixHom Φ.ΦA, ΦB := MIPRE.BipartiteModel.mapMatrixHom Φ.ΦB, intertwineA := ⋯, intertwineB := ⋯ }
Instances For
The extension carries the state to the state when the local isometry does.
Local isometries extend along a one-sided ancilla #
The isometry of the one-sided extensions, componentwise.
Equations
- Φ.expandAW t₀ = (M'.amplA t₀).symm.toLinearIsometry.comp ((MIPRE.BipartiteModel.amplMap Φ.W).comp (M.amplA t₀).toLinearIsometry)
Instances For
A local isometry extends along a one-sided ancilla: the first player's block matrices are mapped entrywise, the second player's operators as before.
Equations
Instances For
The extension carries the state to the state when the local isometry does.
Exchanging an ancilla with a register #
The isometry exchanging the ancilla and the register coordinates.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The exchange of a one-sided ancilla with a register: the one-sided extension of an
extension into the extension of the one-sided extension, the first player's block matrices of
block matrices exchanged layer for layer (layerSwap), the second player's unchanged.
Equations
- One or more equations did not get rendered due to their size.