zeno.qclQCL (Quantum Computation Language) is a programming language for quantum computers, including a quantum computer simulator while we wait for the real quantum computers. zeno.qcl is a small program written in QCL that demonstrates the quantum zeno effect.Download
Measurements can be done in 3 ways:
The qubit is initialized to 0> and is rotated in nrsteps steps,
with pi/steps radians each. Without measurement, it should be
rotated to 1>.
Variant 3 will of course take longer time to run since QCL needs to
calculate the entagled state with the environment instead of just
randomly choosing one environment state, but on the plus side the
final dump shows the probability for qubit flipping, which will
decrease if nrsteps is increased.
Examples:
Example output with three rotations and Larger Hilbert Space option:
$ qcl f b zeno.qcl x 'zeno(2, 3)' QCL Quantum Computation Language (64 qubits, seed 4711) : STATE: 4 / 64 qubits allocated, 60 / 64 qubits free 1 0000> : Step 0 Fanned out internal state to environment. : STATE: 4 / 64 qubits allocated, 60 / 64 qubits free 1 0000> : SPECTRUM q: <0> 1 0> : Rotating 1.0472 radians. : STATE: 4 / 64 qubits allocated, 60 / 64 qubits free 0.86603 0000>  0.5 0001> : Step 1 Fanned out internal state to environment. : STATE: 4 / 64 qubits allocated, 60 / 64 qubits free 0.86603 0000>  0.5 0101> : SPECTRUM q: <0> 0.75 0>, 0.25 1> : Rotating 1.0472 radians. : STATE: 4 / 64 qubits allocated, 60 / 64 qubits free 0.75 0000>  0.43301 0001>  0.25 0100>  0.43301 0101> : Step 2 Fanned out internal state to environment. : STATE: 4 / 64 qubits allocated, 60 / 64 qubits free 0.75 0000>  0.25 0100>  0.43301 1001>  0.43301 1101> : SPECTRUM q: <0> 0.625 0>, 0.375 1> : Rotating 1.0472 radians. : SPECTRUM q: <0> 0.5625 0>, 0.4375 1> : Final state: 0 : SPECTRUM q: <0> 1 0> $ 

Jörgen Cederlöf <jc@lysator.liu.se> 