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Circuits ​

Stateful Simulator work and reusable Circuit sampling. Every gate returns self, so calls chain; classical feedback is just plain Python.

Bell state and its stabilizers ​

Prepare |Φ+⟩=(|00⟩+|11⟩)/2 and read its canonical stabilizer generators.

python
from qliff import Simulator

sim = Simulator(2).H(0).CX(0, 1)
sim.canon()        # ['+XX', '+ZZ']

The state is stabilized by +XX and +ZZ.

GHZ state on n qubits ​

Spread one Hadamard across a CX chain to build |GHZn⟩=(|0…0⟩+|1…1⟩)/2.

python
from qliff import Simulator

n = 4
sim = Simulator(n).H(0)
for q in range(n - 1):
    sim.CX(q, q + 1)

sim.canon()        # ['+XXXX', '+ZIIZ', '+IZIZ', '+IIZZ']

The generators are X⊗n plus the neighbouring ZiZi+1 parities.

Sample measurement bitstrings ​

Build a circuit, measure, and draw many shots at once with Circuit.sample.

python
from qliff import Circuit

c = Circuit(2)
c.H(0).CX(0, 1).M(0, 1)

shots = c.sample(1000, seed=0)

Every record is [0, 0] or [1, 1] — the two Bell outcomes, in equal proportion.

Mid-circuit measurement and reset ​

Use M/MR/R mid-circuit and read the running outcomes off sim.record.

python
from qliff import Simulator

sim = Simulator(1, seed=0)
sim.H(0)
sim.MR(0)
sim.X(0)
sim.M(0)

sim.record         # e.g. [0, 1] or [1, 1]

record lists past outcomes in order; MR collapses then resets, so the final M is deterministic. Call sim.clear() to empty the record.

Classically-conditioned correction: teleportation ​

Teleport a state from qubit 0 onto qubit 2, applying Pauli corrections conditioned on the two measured bits.

python
from qliff import Simulator

sim = Simulator(3, seed=0)
sim.H(0)
sim.H(1).CX(1, 2)
sim.CX(0, 1).H(0)
if sim.M(1) == 1:
    sim.X(2)
if sim.M(0) == 1:
    sim.Z(2)

sim.peek("__X")        # +1

The message lands on qubit 2 regardless of the random outcomes: ⟨X⟩=+1.

Read ⟨P⟩ without collapse ​

peek returns ⟨P⟩∈{−1,0,+1} and leaves the state untouched.

python
from qliff import Simulator

sim = Simulator(2).H(0).CX(0, 1)
sim.peek("ZZ")         # +1
sim.peek("ZI")         # 0

A 0 means the state is not an eigenstate of P; the simulator is unchanged, so you can keep going.