A quantum circuit simulator using tensor network methods.
Install
To get started, run following commands:
import Pkg
# to install ITensors.jl
ITensorsPkg = Pkg.PackageSpec(url="https://github.com/ITensor/ITensors.jl.git")
# to install LinQu
LinQuPkg = Pkg.PackageSpec(url="https://github.com/YiqingZhouKelly/LinQu.jl.git")
Pkg.add([ITensorsPkg, LinQuPkg])
Then you should be ready to go!
Tutorial
(For more detailed examples, checkout the example
folder.)
 Construct a state
N = 5 # for 5 qubits
state1 = MPSState(N) # use MPS to represent state of a quantum device
state2 = ExactState(N) # use a tensor of order N to represent state of a quantum device

Apply a gate
 Single qubit gate
apply!(state, H, 1) # apply a Hadamard gate to qubit 1 apply!(state, H(1)) # alternative interface
 Multiple qubit gate
# apply a CNOT gate to state, qubit 3 is control bit and qubit 5 is target bit apply!(state, CNOT, [3,5]) apply!(state, CNOT(3,5))
 Single qubit gate

Build a QCircuit
N = 10 # 10 quits
state = MPSState(N)
circuit = QCircuit(N)
add!(circuit, H, 1)
add!(circuit, H(1),
X(2),
CNOT(1,2))
apply!(state, circuit)
 Allow SVD truncation for approximation
N = 10 # 10 quits
state = MPSState(N)
circuit = QCircuit(N)
add!(circuit, H, 1)
add!(circuit, H(1),
X(2),
CNOT(1,2))
apply!(state, circuit; maxdim = 10) # use keyword arguments
# to specify truncation
# mode
# see doc string of apply! function for a complete set of supported keyword arguments
 Measurements
measure!
: This function does not change the current state physically, but may change the gauge center.collapse!
: This function collapses measured qubits to measurement results (i.e. changes the physical meaning current state).
julia> state = MPSState(10)
10qubit MPSState
julia> apply!(state, H, 1)
10qubit MPSState
julia> measure!(state, 1, 3)
3element Array{Int64,1}:
0
1
0
julia> measure!(state, 1, 3)
3element Array{Int64,1}:
1
0
0
julia> collapse!(state, 1)
0
julia> sum(measure!(state, 1, 100)) #always get zero after calling collapse!
0