qrisp.QuantumCircuit.to_stim#

QuantumCircuit.to_stim(return_measurement_map=False, return_detector_map=False, return_observable_map=False)[source]#

Method to convert the given QuantumCircuit to a Stim Circuit.

Note

Stim can only process/represent Clifford operations.

Parameters:

return_measurement_mapbool, optional: If set to True, the function returns the measurement_map, as described below. The default is False.
return_detector_mapbool, optional: If set to True, the function returns the detector_map. The default is False.
return_observable_mapbool, optional: If set to True, the function returns the observable_map. The default is False.

Returns:

stim_circuitstim.Circuit: The converted Stim circuit.
measurement_mapdict: (Optional) A dictionary mapping Qrisp Clbit objects to Stim measurement record indices. For example, {Clbit(cb_1): 2, Clbit(cb_0): 1} means Clbit("cb_1") corresponds to index 2 in Stim’s measurement record.
detector_mapdict: (Optional) A dictionary mapping ParityHandle objects to Stim detector indices. ParityHandle objects are compared by their index, so handles from to_qc() can be used directly as keys.
observable_mapdict: (Optional) A dictionary mapping ParityHandle objects to Stim observable indices. ParityHandle objects are compared by their index, so handles from to_qc() can be used directly as keys.

Examples

Basic conversion:

>>> from qrisp import QuantumCircuit
>>> qc = QuantumCircuit(2, 2)
>>> qc.x(0)
>>> qc.cz(0, 1)
>>> qc.measure(0, 0)
>>> qc.measure(1, 1)
>>> print(qc)
      ┌───┐   ┌─┐
qb_0: ┤ X ├─■─┤M├───
      └───┘ │ └╥┘┌─┐
qb_1: ──────■──╫─┤M├
               ║ └╥┘
cb_0: ═════════╩══╬═
                  ║
cb_1: ════════════╩═

>>> stim_circuit = qc.to_stim()
>>> print(stim_circuit)
X 0
CZ 0 1
M 0 1

Stim creates measurement indices in the order of how the measurements appear in the circuit. This is different in Qrisp: It is for instance possible for the first measurement of the circuit to target the second Clbit. The second measurement can in-principle then target either the first or the second Clbit. In order to still identify which Clbit corresponds to which stim measurement index, we can use the return_measurement_map keyword argument.

>>> qc = QuantumCircuit(2, 2)
>>> qc.x(0)
>>> qc.cz(0, 1)
>>> qc.measure(1, 1) # The first measurement of the circuit targets the second ClBit
>>> qc.measure(0, 0) # The second measurement of the circuit targets the first ClBit
>>> print(qc)
      ┌───┐      ┌─┐
qb_0: ┤ X ├─■────┤M├
      └───┘ │ ┌─┐└╥┘
qb_1: ──────■─┤M├─╫─
              └╥┘ ║
cb_0: ═════════╬══╩═
               ║
cb_1: ═════════╩════
>>> stim_circuit, measurement_map = qc.to_stim(return_measurement_map = True)
>>> print(stim_circuit)
X 0
CZ 0 1
M 1 0

We see that Stim now measures the qubit with index 1 first (M 1 0), which is why in the measurement record the measurement result in Clbit("cb_1") will appear at index 0 and Clbit("cb_0") at index 1. To retrieve the correct order, we inspect the measurement_map dictionary.

>>> print(measurement_map)  # Maps Clbit objects to Stim measurement indices
{Clbit(cb_1): 0, Clbit(cb_0): 1}

We can now check the samples drawn from this circuit for a given Clbit object by slicing the sampling result array.

>>> sampler = stim_circuit.compile_sampler()
>>> all_samples = sampler.sample(5)
>>> samples = all_samples[:, measurement_map[qc.clbits[0]]]
>>> print(samples)
array([ True,  True,  True,  True,  True])