Hi all,

I am experimenting with strawberry field and I wanted to look at the effect of cutoff dimension on the representation of very squeezed states.8

I have a circuit to generate the squeezed state :

```
def fun_squeeze(n,p,cutoff_dim=50):
prog = sf.Program(1)
eng = sf.Engine("fock", backend_options={"cutoff_dim": cutoff_dim})
with prog.context as q:
Fock(n) | q[0]
Sgate(p) | q[0]
results = eng.run(prog)
state = results.state
return state
```

A function to plot the wigner function (copy pasted from strawberry field documentation):

```
def fun_wigner(state,qmode=0,lims = 5):
fig = plt.figure()
X = np.linspace(-lims, lims, 100)
P = np.linspace(-lims, lims, 100)
Z = state.wigner(qmode, X, P)
return Z
```

And a script to look at how it evolves for different cut-off dimension :

```
ds = [10,20,50,100,200,500]
fig, axs = plt.subplots(1,len(ds),figsize=(3*len(ds),3*1), subplot_kw = {"projection":"3d"})
Zs = []
states = []
for k,ax in enumerate(axs.flat):
state = fun_squeeze(0,2,cutoff_dim=ds[k])
states.append(state)
Zs.append(plot_wigner(state,ax=ax))
```

As can be seen for the 200 and 500 cutoff dimension the Wigner function starts to show instability (the data in the state is fine). Is that expected ? I could not find any maximum for the cutoff dimension or the Wigner function of the Fock backend in the documentation of strawberry fields.

I am using the Fock backend because I will need to use it for the next steps in my project.