Hello I’m trying to see destructive interference of from Mach Zehnder interferometer when the phase difference between the two arms is pi. Here’s the script:

```
import strawberryfields as sf
from strawberryfields.ops import *
import numpy as np
import plotly.graph_objects as go
from plotly.subplots import make_subplots
# start here:
prog = sf.Program(2)
eng = sf.Engine("gaussian", backend_options={"cutoff_dim": 10})
with prog.context as q:
Coherent(2, 0) | q[0]
Coherent(2, 0) | q[1]
MZgate(np.pi, 0) | (q[0], q[1])
#eng.reset()
state = eng.run(prog).state
results = eng.run(prog)
plt.figure(figsize = (10, 5))
for i in range(2):
plt.subplot(1, 2, i + 1)
X = np.linspace(-10, 10, 100)
P = np.linspace(-10, 10, 100)
Z = state.wigner(i, X, P)
X, P = np.meshgrid(X, P)
plt.pcolormesh(X, P, Z, cmap = 'RdBu_r')
plt.xlabel('X'); plt.ylabel('P')
plt.tight_layout()
plt.show()
```

I don’t think I see any interference as a function of the `phi_in `

of the `MZgate`

. I tried both `gaussian`

and `fock`

bases. Maybe my displacement operator is only `2`

is causing problem since it might Hong-Ou-Mandel?