58 lines
1.4 KiB
Python
58 lines
1.4 KiB
Python
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from sympy.core.numbers import I
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from sympy.core.symbol import symbols
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from sympy.physics.paulialgebra import Pauli
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from sympy.testing.pytest import XFAIL
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from sympy.physics.quantum import TensorProduct
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sigma1 = Pauli(1)
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sigma2 = Pauli(2)
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sigma3 = Pauli(3)
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tau1 = symbols("tau1", commutative = False)
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def test_Pauli():
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assert sigma1 == sigma1
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assert sigma1 != sigma2
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assert sigma1*sigma2 == I*sigma3
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assert sigma3*sigma1 == I*sigma2
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assert sigma2*sigma3 == I*sigma1
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assert sigma1*sigma1 == 1
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assert sigma2*sigma2 == 1
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assert sigma3*sigma3 == 1
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assert sigma1**0 == 1
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assert sigma1**1 == sigma1
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assert sigma1**2 == 1
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assert sigma1**3 == sigma1
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assert sigma1**4 == 1
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assert sigma3**2 == 1
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assert sigma1*2*sigma1 == 2
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def test_evaluate_pauli_product():
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from sympy.physics.paulialgebra import evaluate_pauli_product
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assert evaluate_pauli_product(I*sigma2*sigma3) == -sigma1
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# Check issue 6471
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assert evaluate_pauli_product(-I*4*sigma1*sigma2) == 4*sigma3
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assert evaluate_pauli_product(
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1 + I*sigma1*sigma2*sigma1*sigma2 + \
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I*sigma1*sigma2*tau1*sigma1*sigma3 + \
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((tau1**2).subs(tau1, I*sigma1)) + \
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sigma3*((tau1**2).subs(tau1, I*sigma1)) + \
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TensorProduct(I*sigma1*sigma2*sigma1*sigma2, 1)
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) == 1 -I + I*sigma3*tau1*sigma2 - 1 - sigma3 - I*TensorProduct(1,1)
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@XFAIL
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def test_Pauli_should_work():
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assert sigma1*sigma3*sigma1 == -sigma3
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