From 87a71144d1cf169027ac4d81ecfa788fd6f41e69 Mon Sep 17 00:00:00 2001 From: ddahlbom Date: Wed, 16 Oct 2024 14:46:08 -0400 Subject: [PATCH] Add function to specify cs of entangled unit from dipoles --- src/EntangledUnits/TypesAndAliasing.jl | 24 +++++++++++++++++++++++- test/test_entangled_units.jl | 7 +++++++ 2 files changed, 30 insertions(+), 1 deletion(-) diff --git a/src/EntangledUnits/TypesAndAliasing.jl b/src/EntangledUnits/TypesAndAliasing.jl index b76689112..dc41f9221 100644 --- a/src/EntangledUnits/TypesAndAliasing.jl +++ b/src/EntangledUnits/TypesAndAliasing.jl @@ -149,7 +149,29 @@ function set_field_at!(::EntangledSystem, _, _) end -set_dipole!(esys::EntangledSystem, dipole, site; kwargs...) = error("Setting dipoles of an EntangledSystem not well defined.") +function set_dipole!(::EntangledSystem, dipole, site) + error("`set_dipole!` operation for `EntangledSystem` not well defined. Consider using `set_coherent!` to set the state of each entangled unit.") +end + +# Find the unique coherent state corresponding to a set of fully-polarized +# dipoles on each site inside a specified entangled unit. +function coherent_state_from_dipoles(esys::EntangledSystem, dipoles, unit) + (; sys_origin, contraction_info) = esys + + original_sites = [id.site for id in contraction_info.inverse[unit]] + Ns = Ns_in_units(sys_origin, contraction_info)[unit] + + @assert length(dipoles) == length(original_sites) == length(Ns) "Invalid number of dipoles for specified unit." + + coherents = [] + for (dipole, N) in zip(dipoles, Ns) + S = spin_matrices((N-1)/2) + coherent = eigvecs(S' * dipole)[:,N] # Retrieve highest-weight eigenvector + push!(coherents, coherent) + end + + return kron(coherents...) +end # Sets the coherent state of a specified unit. The `site` refers to the # contracted lattice (i.e., to a "unit"). The function then updates all dipoles diff --git a/test/test_entangled_units.jl b/test/test_entangled_units.jl index ea89ca637..6b8837c96 100644 --- a/test/test_entangled_units.jl +++ b/test/test_entangled_units.jl @@ -55,6 +55,13 @@ end field_offset = 2*(Sl[3] + Su[3]) # 2 for g-factor @test onsite_operator ≈ onsite_ref + field_offset + # Test apparatus for setting coherent states from dipoles specification + dipoles = [[0, 1/2, 0], [0, -1/2, 0]] # Dipoles specifying a dimer state + cs = Sunny.coherent_state_from_dipoles(esys, dipoles, 1) + set_coherent!(esys, cs, CartesianIndex(1,1,1,1)) + @test esys.sys_origin.dipoles[1,1,1,1][2] ≈ 1/2 + @test esys.sys_origin.dipoles[1,1,1,2][2] ≈ -1/2 + # Test external field works in action set_field!(esys, [0, 0, 10]) randomize_spins!(esys)