This package contains special methods for efficiently representing sparse local quantum operators that act on a tensor product space. The most important methods are:
using QuantumTensors
# Create a creation operator with N basis states
create(N)
# Create an annihilation operator with N basis states
destroy(N)
# Create an angular momentum J-z operator
jz(N)
# Create a truncated angular momentum J_z operator with only K basis states
jz(J, K)
# Create an angular momentum J_+ operator (with optional basis truncation)
jplus(J, K)
# Create an angular momentum J_- operator (with optional basis truncation)
jminus(J, K)
# products within a local degree of freedom
jz(J,K) * jplus(J,K)
# form a tensor product between different degrees of freedom
tensor(jz(J), create(N))
# in-place apply a single tensor product operator to a state
# (needs to be an array with as many dimensions as the tensor product factors)
A_mul_B!(λ, A, Ψ, μ, Φ) ==> Φ -> μ Φ + λ A.Ψ
# in-place apply a sequence single tensor product operators to a state
# with certain coefficients (supports CSR type sparse matrices as well)
apply_serial!([λ1,λ2], [A1,A2], Ψ, μ, Φ) ==> Φ -> μ Φ + λ1 A1.Ψ + λ2 A2.Ψ
Documentation will fleshed out more soon. See the tests for some further usage examples.