37 lines
1.1 KiB
Python
37 lines
1.1 KiB
Python
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from sympy.physics.quantum import Dagger, AntiCommutator, qapply
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from sympy.physics.quantum.fermion import FermionOp
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from sympy.physics.quantum.fermion import FermionFockKet, FermionFockBra
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def test_fermionoperator():
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c = FermionOp('c')
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d = FermionOp('d')
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assert isinstance(c, FermionOp)
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assert isinstance(Dagger(c), FermionOp)
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assert c.is_annihilation
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assert not Dagger(c).is_annihilation
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assert FermionOp("c") == FermionOp("c", True)
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assert FermionOp("c") != FermionOp("d")
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assert FermionOp("c", True) != FermionOp("c", False)
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assert AntiCommutator(c, Dagger(c)).doit() == 1
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assert AntiCommutator(c, Dagger(d)).doit() == c * Dagger(d) + Dagger(d) * c
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def test_fermion_states():
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c = FermionOp("c")
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# Fock states
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assert (FermionFockBra(0) * FermionFockKet(1)).doit() == 0
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assert (FermionFockBra(1) * FermionFockKet(1)).doit() == 1
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assert qapply(c * FermionFockKet(1)) == FermionFockKet(0)
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assert qapply(c * FermionFockKet(0)) == 0
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assert qapply(Dagger(c) * FermionFockKet(0)) == FermionFockKet(1)
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assert qapply(Dagger(c) * FermionFockKet(1)) == 0
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