You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
63 lines
1.6 KiB
63 lines
1.6 KiB
from pytest import raises
|
|
|
|
import sympy
|
|
from sympy.physics.quantum import Dagger, AntiCommutator, qapply
|
|
from sympy.physics.quantum.fermion import FermionOp
|
|
from sympy.physics.quantum.fermion import FermionFockKet, FermionFockBra
|
|
from sympy import Symbol
|
|
|
|
|
|
def test_fermionoperator():
|
|
c = FermionOp('c')
|
|
d = FermionOp('d')
|
|
|
|
assert isinstance(c, FermionOp)
|
|
assert isinstance(Dagger(c), FermionOp)
|
|
|
|
assert c.is_annihilation
|
|
assert not Dagger(c).is_annihilation
|
|
|
|
assert FermionOp("c") == FermionOp("c", True)
|
|
assert FermionOp("c") != FermionOp("d")
|
|
assert FermionOp("c", True) != FermionOp("c", False)
|
|
|
|
assert AntiCommutator(c, Dagger(c)).doit() == 1
|
|
|
|
assert AntiCommutator(c, Dagger(d)).doit() == c * Dagger(d) + Dagger(d) * c
|
|
|
|
|
|
def test_fermion_states():
|
|
c = FermionOp("c")
|
|
|
|
# Fock states
|
|
assert (FermionFockBra(0) * FermionFockKet(1)).doit() == 0
|
|
assert (FermionFockBra(1) * FermionFockKet(1)).doit() == 1
|
|
|
|
assert qapply(c * FermionFockKet(1)) == FermionFockKet(0)
|
|
assert qapply(c * FermionFockKet(0)) == 0
|
|
|
|
assert qapply(Dagger(c) * FermionFockKet(0)) == FermionFockKet(1)
|
|
assert qapply(Dagger(c) * FermionFockKet(1)) == 0
|
|
|
|
|
|
def test_power():
|
|
c = FermionOp("c")
|
|
assert c**0 == 1
|
|
assert c**1 == c
|
|
assert c**2 == 0
|
|
assert c**3 == 0
|
|
assert Dagger(c)**1 == Dagger(c)
|
|
assert Dagger(c)**2 == 0
|
|
|
|
assert (c**Symbol('a')).func == sympy.core.power.Pow
|
|
assert (c**Symbol('a')).args == (c, Symbol('a'))
|
|
|
|
with raises(ValueError):
|
|
c**-1
|
|
|
|
with raises(ValueError):
|
|
c**3.2
|
|
|
|
with raises(TypeError):
|
|
c**1j
|