added new file for defining standard Hamiltonians

abhirup-m · Nov 1, 2024 · 2c9f956 · 2c9f956
1 parent 4759df8
commit 2c9f956
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Showing 3 changed files with 45 additions and 2 deletions.
diff --git a/src/correlations.jl b/src/correlations.jl
@@ -271,10 +271,14 @@ function SpecFunc(
     freqValues::Vector{Float64},
     standDev::Union{Vector{Float64}, Float64};
     normalise::Bool=true,
+
     )
+
+    println("E: ", round.(eigVals, digits=5), length(eigVals))
+
     @assert length(eigVals) == length(eigVecs)
 
-    #=println("EM: ", sort(round.(eigVals, digits=5)), length(eigVals))=#
+    @assert issorted(freqValues)
 
     groundState = eigVecs[sortperm(eigVals)[1]]
     energyGs = round(minimum(eigVals), digits=10)
@@ -293,6 +297,7 @@ function SpecFunc(
         specFunc .+= spectralWeights[index][1] * deltaFunction(freqValues .+ energyGs .- eigVals[index], standDev) # standDev ./ ((freqValues .+ energyGs .- eigVals[index]) .^ 2 .+ standDev^2)
         specFunc .+= spectralWeights[index][2] * deltaFunction(freqValues .- energyGs .+ eigVals[index], standDev) # standDev ./ ((freqValues .- energyGs .+ eigVals[index]) .^ 2 .+ standDev^2)
     end
+
     if sum(specFunc .* (maximum(freqValues) - minimum(freqValues[1])) / (length(freqValues) - 1)) > 1e-10 && normalise
         return specFunc ./ sum(specFunc .* (maximum(freqValues) - minimum(freqValues[1])) / (length(freqValues) - 1))
     else
@@ -346,6 +351,7 @@ function SpecFunc(
     basisStates::Vector{Dict{BitVector,Float64}},
     standDev::Union{Vector{Float64}, Float64};
     normalise::Bool=true,
+
 )
 
     eigenStates = [ExpandIntoBasis(vector, basisStates) for vector in eigVecs]
@@ -376,8 +382,8 @@ function SpecFunc(
     standDev::Union{Vector{Float64}, Float64},
     symmetries::Vector{Char};
     normalise::Bool=true,
-)
 
+)
     classifiedSpectrum, classifiedEnergies = ClassifyBasis(eigVecs, symmetries; energies=eigVals)
     groundStateEnergy = minimum(eigVals)
     groundState = eigVecs[sortperm(eigVals)[1]]
@@ -411,6 +417,7 @@ function SpecFunc(
     symmetries::Vector{Char},
     groundStateSector::Union{Tuple{Int64}, Tuple{Int64,Int64}};
     normalise::Bool=true,
+
 )
 
     #=println("E: ", round.(eigVals, digits=5))=#

diff --git a/src/fermions.jl b/src/fermions.jl
@@ -11,5 +11,6 @@ include("reverseUnitaries.jl")
 include("stateExpansion.jl")
 include("iterDiag.jl")
 include("thermalisation.jl")
+include("modelHamiltonians.jl")
 
 end
diff --git a/src/modelHamiltonians.jl b/src/modelHamiltonians.jl
@@ -0,0 +1,35 @@
+function KondoModel(
+        numBathSites::Int64,
+        hop_t::Float64,
+        kondoJ::Float64;
+        globalField::Float64=0.,
+    )
+    hamiltonian = Tuple{String, Vector{Int64}, Float64}[]
+
+    # intra-bath hopping
+    for site in 1:(numBathSites-1)
+        push!(hamiltonian, ("+-",  [1 + 2 * site, 3 + 2 * site], -hop_t)) # c^†_{j,up} c_{j+1,up}
+        push!(hamiltonian, ("+-",  [3 + 2 * site, 1 + 2 * site], -hop_t)) # c^†_{j+1,up} c_{j,up}
+        push!(hamiltonian, ("+-",  [2 + 2 * site, 4 + 2 * site], -hop_t)) # c^†_{j,dn} c_{j+1,dn}
+        push!(hamiltonian, ("+-",  [4 + 2 * site, 2 + 2 * site], -hop_t)) # c^†_{j+1,dn} c_{j,dn}
+    end
+
+    # kondo terms
+    push!(hamiltonian, ("nn",  [1, 3], kondoJ/4)) # n_{d up, n_{0 up}
+    push!(hamiltonian, ("nn",  [1, 4], -kondoJ/4)) # n_{d up, n_{0 down}
+    push!(hamiltonian, ("nn",  [2, 3], -kondoJ/4)) # n_{d down, n_{0 up}
+    push!(hamiltonian, ("nn",  [2, 4], kondoJ/4)) # n_{d down, n_{0 down}
+    push!(hamiltonian, ("+-+-",  [1, 2, 4, 3], kondoJ/2)) # S_d^+ S_0^-
+    push!(hamiltonian, ("+-+-",  [2, 1, 3, 4], kondoJ/2)) # S_d^- S_0^+
+
+    # global magnetic field (to lift any trivial degeneracy)
+    if globalField ≠ 0
+        for site in 0:numBathSites
+            push!(hamiltonian, ("n",  [1 + 2 * site], field))
+            push!(hamiltonian, ("n",  [2 + 2 * site], -field))
+        end
+    end
+
+    return hamiltonian
+end
+export KondoModel