`libquantum` provides an efficient model to simulate the effects of
decoherence. The effects are simulated by a random rotation about the
z axis, where the angle of the rotation is a normal distributed value
with the variance . is the decoherence parameter,
which depends on the experimental realization of the quantum
computer. A list of values for is given in [DiVincenzo, 1995].

extern void quantum_set_decoherence(float lambda); |

This function sets the decoherence parameter which affects all following quantum operations.

extern void quantum_decohere(quantum_reg *reg); |

Perform a decoherence step on a quantum register. Note that this
function gets called automatically by all elementary gates provided by `libquantum`.