pygsti.extras.idletomography.pauliobjs.NQPauliState

class NQPauliState(string_rep, signs=None)

Bases: object

A N-qubit state that is the tensor product of N 1-qubit Pauli eigenstates. These can be represented as a string of Xs, Ys and Zz (but not Is) each with a +/- sign indicating which of the two eigenstates is meant.

A NQPauliState object can also be used to represent a POVM whose effects are the projections onto the 2^N tensor products of (the given) Pauli eigenstates. The +/- sign in this case indicates which eigenstate is equated with the “0” (vs “1”) outcome.

Create a NQPauliState

Parameters:

• string_rep (str) – A string with letters in {X,Y,Z} (note: I is not allowed!), specifying the Pauli basis for each qubit.

• signs (tuple, optional) – A tuple of 0s and/or 1s. A zero means the “+” eigenvector is either prepared or corresponds to the “0” outcome (if this NQPauliState is used to describe a measurment basis). A one means the opposite: the “-” eigenvector is prepared and it corresponds to a “0” outcome. The default is all zeros.

Methods

__init__(string_rep[, signs])	Create a NQPauliState
to_circuit(pauli_basis_dict)	Convert this Pauli basis state or measurement to a fiducial operation sequence.

to_circuit(pauli_basis_dict)

Convert this Pauli basis state or measurement to a fiducial operation sequence.

When the returned operation sequence follows a preparation in the |0…0> Z-basis state or is followed by a Z-basis measurement (with all “+” signs), then the Pauli state preparation or measurement described by this object will be performed.

Parameters:

pauli_basis_dict (dict) – A dictionary w/keys like “+X” or “-Y” and values that are tuples of gate names (not labels, which include qubit or other state-space designations), e.g. (“Gx”,”Gx”). This dictionary describes how to prepare or measure in Pauli bases.

Return type:

Circuit