def n_operator(self) -> ndarray:
"""
Returns
-------
Returns the :math:`n = - i d/d\\phi` operator in the LC harmonic oscillator basis
"""
dimension = self.hilbertdim()
return 1j * (op.creation(dimension) - op.annihilation(dimension)) / (
self.phi_osc() * math.sqrt(2))
def phi_operator(self) -> ndarray:
"""
Returns
-------
Returns the phi operator in the LC harmonic oscillator basis
"""
dimension = self.hilbertdim()
return (op.creation(dimension) +
op.annihilation(dimension)) * self.phi_osc() / math.sqrt(2)
def phi_operator(self) -> ndarray:
r"""Returns the phase operator defined as
:math:`l_\text{osc} (a + a^{\dagger})/\sqrt{2}`, with :math:`a` representing
an annihilation operator, and :math:`l_\text{osc}` the oscillator length.
"""
if self.l_osc is None:
raise ValueError(
"Variable l_osc has to be set to something other than None\n" +
"in order to use the phi_operator() method. This can be done by either\n"
+
"passing it to the class constructor, or by setting it afterwords."
)
a = op.annihilation(self.truncated_dim)
return self.l_osc / np.sqrt(2) * (a + a.T)
def annihilation_operator(self):
"""Returns the creation operator"""
return op.annihilation(self.truncated_dim)
