Spin-flip symmetry and the Peierls long-range-order criterion
A. The global spin flip
DefinitionGlobal spin flip of a configuration#✓fully proved
The global spin flip σ ↦ -σ of an infinite-volume configuration.
def flipConfig (s : ConfigSpace (Site d)) : ConfigSpace (Site d) := fun y => !(s y)
abbrev ConfigSpace (E : Type*) : Type _ := E → Bool
MathlibExt/Probability/Configuration/ConfigSpace.lean:40
abbrev Site (d : ℕ) : Type := Fin d → ℤ
MathlibExt/Combinatorics/SimpleGraph/Lattice/HypercubicLattice.lean:55
Uses 2 · Used by 1
DefinitionSpin flip inside the box#✓fully proved
The spin flip of a configuration inside the box Λ_n.
DefinitionSpin flip inside the box as an involutive equivalence#✓fully proved
The spin flip inside the box as an involutive equivalence.
def flipInteriorEquiv {n : ℕ} :
({x // x ∈ box d n} → Bool) ≃ ({x // x ∈ box d n} → Bool) where
toFun := flipInterior
invFun := flipInterior
left_inv := flipInterior_involutive
right_inv := flipInterior_involutive
def box (d n : ℕ) : Set (Site d) := {x | ∀ i, (x i).natAbs ≤ n}
MathlibExt/Combinatorics/SimpleGraph/Lattice/HypercubicLattice.lean:86
def flipInterior {n : ℕ} (τ : {x // x ∈ box d n} → Bool) : {x // x ∈ box d n} → Bool :=
fun x => !(τ x)
PhyslibExt/CondensedMatter/IsingModel/Peierls.lean:74
lemma flipInterior_involutive {n : ℕ} (τ : {x // x ∈ box d n} → Bool) :
flipInterior (flipInterior τ) = τ
PhyslibExt/CondensedMatter/IsingModel/Peierls.lean:83
Uses 3 · Used by 1
C. Magnetization at the origin
DefinitionOrigin of \(\mathbb{Z}^d\)#✓fully proved
The origin of ℤ^d.
def origin (d : ℕ) : Site d := fun _ => 0
abbrev Site (d : ℕ) : Type := Fin d → ℤ
MathlibExt/Combinatorics/SimpleGraph/Lattice/HypercubicLattice.lean:55
Uses 1 · Used by 21
DefinitionFinite-volume magnetization at the origin#✓fully proved
The magnetization ⟨σ_0⟩ at the origin in the finite-volume Ising measure on Λ_n with
boundary condition η, bond set B, inverse temperature β and field h.
noncomputable def fvMagOrigin (η : ConfigSpace (Site d)) (n : ℕ)
(B : Finset (Sym2 (Site d))) (β h : ℝ) : ℝ :=
∑ τ : {x // x ∈ box d n} → Bool, fvProb η n B β h τ * spin (glue η τ) (origin d)
abbrev ConfigSpace (E : Type*) : Type _ := E → Bool
MathlibExt/Probability/Configuration/ConfigSpace.lean:40
abbrev Site (d : ℕ) : Type := Fin d → ℤ
MathlibExt/Combinatorics/SimpleGraph/Lattice/HypercubicLattice.lean:55
def box (d n : ℕ) : Set (Site d) := {x | ∀ i, (x i).natAbs ≤ n}
MathlibExt/Combinatorics/SimpleGraph/Lattice/HypercubicLattice.lean:86
noncomputable def fvProb (η : ConfigSpace (Site d)) (n : ℕ)
(B : Finset (Sym2 (Site d))) (β h : ℝ) (τ : {x // x ∈ box d n} → Bool) : ℝ :=
fvWeight η n B β h τ / fvZ η n B β h
PhyslibExt/CondensedMatter/IsingModel/InfiniteVolume.lean:177
def spin (s : ConfigSpace V) (x : V) : ℝ := if s x then 1 else -1
PhyslibExt/CondensedMatter/IsingModel/Gibbs.lean:70
noncomputable def glue (η : ConfigSpace (Site d)) {n : ℕ}
(τ : {x // x ∈ box d n} → Bool) : ConfigSpace (Site d) :=
fun x => if h : x ∈ box d n then τ ⟨x, h⟩ else η x
PhyslibExt/CondensedMatter/IsingModel/InfiniteVolume.lean:125
def origin (d : ℕ) : Site d := fun _ => 0
PhyslibExt/CondensedMatter/IsingModel/Peierls.lean:195
Uses 7 · Used by 2
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