# Det(i)

takes one argument: i - unsigned integer

for a wavefunction psi psi.Det(i) returns determinant i of psi as a new wavefunction. psi.Det(i) is read only and can not be used to change the value of a determinant.

## Example

We can define the function: $$|\psi\rangle = \left(\frac{1}{\sqrt{4}} a^{\dagger}_0 a^{\dagger}_1 + \frac{1}{\sqrt{4}} a^{\dagger}_0 a^{\dagger}_2 + (1+I)\frac{1}{\sqrt{4}} a^{\dagger}_1 a^{\dagger}_2 \right)|0\rangle.$$ In the example we set the name of the function to “psi” and then print determinant 1, 2 and 3 of the function. Note that operations acting on wavefunctions must not keep the order of determinants fixed. The only safe use of this function is probably in cases where one loops over all determinants in the function.

### Input

Example.Quanty
NF=3
NB=0
psi = NewWavefunction(NF, NB, {{"110",sqrt(1/4)},{"101",sqrt(1/4)},{"011",(1+I)*sqrt(1/4)}})
psi.Name="psi"
print(psi.Det(1))
print(psi.Det(2))
print(psi.Det(3))

### Result

WaveFunction: psi.Det(1)
QComplex         =          1 (Real==0 or Complex==1)
N                =          1 (Number of basis functions used to discribe psi)
NFermionic modes =          3 (Number of fermions in the one particle basis)
NBosonic modes   =          0 (Number of bosons in the one particle basis)

#      pre-factor             +I  pre-factor         Determinant
1   5.000000000000E-01         0.000000000000E+00       110

WaveFunction: psi.Det(2)
QComplex         =          1 (Real==0 or Complex==1)
N                =          1 (Number of basis functions used to discribe psi)
NFermionic modes =          3 (Number of fermions in the one particle basis)
NBosonic modes   =          0 (Number of bosons in the one particle basis)

#      pre-factor             +I  pre-factor         Determinant
1   5.000000000000E-01         0.000000000000E+00       101

WaveFunction: psi.Det(3)
QComplex         =          1 (Real==0 or Complex==1)
N                =          1 (Number of basis functions used to discribe psi)
NFermionic modes =          3 (Number of fermions in the one particle basis)
NBosonic modes   =          0 (Number of bosons in the one particle basis)

#      pre-factor             +I  pre-factor         Determinant
1   5.000000000000E-01         5.000000000000E-01       011