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@@ -1,44 +1,53 @@ |
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#!/usr/bin/python |
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# -*- coding: utf-8 -*- |
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""" |
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Generates and enumerates the 24 elements of the local Clifford group |
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Following the prescription of Anders (thesis pg. 26): |
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> Table 2.1: The 24 elements of the local Clifford group. The row index (here called the “sign symbol”) shows how the operator |
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> U permutes the Pauli operators σ = X, Y, Z under the conjugation σ = ±UσU† . The column index (the “permutation |
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> symbol”) indicates the sign obtained under the conjugation: For operators U in the I column it is the sign of the permutation |
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> (indicated on the left). For elements in the X, Y and Z columns, it is this sign only if the conjugated Pauli operator is the one |
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> indicated by the column header and the opposite sign otherwise. |
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""" |
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from numpy import * |
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# Some two-qubit matrices |
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i = matrix(eye(2, dtype=complex)) |
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px = matrix([[0, 1], [1, 0]], dtype=complex) |
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py = matrix([[0, -1j], [1j, 0]], dtype=complex) |
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pz = matrix([[1, 0], [0, -1]], dtype=complex) |
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i = matrix(eye(2, dtype=complex)) |
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h = matrix([[1, 1], [1, -1]], dtype=complex) / sqrt(2) |
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p = matrix([[1, 0], [0, 1j]], dtype=complex) |
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paulis = (px, py, pz) |
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s_set = [i, p, p*p, p*p*p] |
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c_set = [i, h, h*p, h*p*p, h*p*p*p, h*p*p*h] |
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# More two-qubit matrices |
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s_rotations = [i, p, p*p, p*p*p] |
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s_names = ["i", "p", "pp", "ppp"] |
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c_rotations = [i, h, h*p, h*p*p, h*p*p*p, h*p*p*h] |
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c_names = ["i", "h", "hp", "hpp", "hppp", "hpph"] |
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def identify_pauli(m): |
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""" Given a signed Pauli matrix, name it. """ |
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for sign in [+1, -1]: |
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for label, pauli in zip("XYZ", (px, py, pz)): |
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for label, pauli in zip("xyz", paulis): |
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if allclose(sign*pauli, m): |
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return "{}{}".format("+" if sign>0 else "-", label) |
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for p in px, py, pz: |
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for sign in [+1, -1]: |
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print identify_pauli(sign*p) |
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def get_action(u): |
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""" Get the action of a Pauli matrix on three qubits """ |
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return tuple(identify_pauli(u*p*u.H) for p in paulis) |
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print py |
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print h*px*h.H |
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print h*py*h.H |
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print h*pz*h.H |
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#names = [] |
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#matrices = [] |
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#for s, s_name in zip(s_set, s_names): |
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#for c, c_name in zip(c_set, c_names): |
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#names.append(s_name+c_name) |
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#matrices.append(s*c) |
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if __name__ == '__main__': |
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permutations = ["xyz", "yxz", "zyx", "xzy", "yzx", "zxy"] |
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#print " ".join(names) |
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#print len(names) |
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#for m in matrices: |
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# print (m/abs(amax(m))).round(0).reshape(4) |
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#print average(abs(array((m/abs(amax(m))).round(0).reshape(4).tolist()[0]))) |
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#for s, sn in zip(s_rotations, s_names): |
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#for c, cn in zip(c_rotations, c_names): |
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#print sn, "\t", cn, "\t", get_action(s*c) |
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