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ass3: Task 12: does not work, but it is something

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Kees van Kempen
2022-03-17 17:12:50 +01:00
parent 72a12920d2
commit a5eea861df
1 changed files with 25 additions and 9 deletions
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34
ass3-12-a-weak-junction.py
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@ -7,21 +7,21 @@ import pandas as pd
#phi_dot = lambda phi, t, I_DC, I_RF, I_J, omega_RF, hbar, e, R: 2*e*R/hbar*( I_DC + I_RF*np.cos(omega_RF*t) - I_J(np.sin(phi)) )
def phi_dot(phi, t, I_DC, I_RF):
R = 10e-3 #Ohm
I_J = 1e-3 #A
R = 10.e-3 #Ohm
I_J = 1.e-3 #A
omega_RF = 2*np.pi*.96e9 #rad/s
hbar = 1.0545718e-34 #m^2kg/s
e = 1.60217662e-19 #C
#return 2*e*R/hbar*( I_DC + I_RF*np.cos(omega_RF*t) - I_J*(np.sin(phi)) )
return R*( I_DC + I_RF*np.sin(omega_RF*t) - I_J*(np.sin(phi)) )
return 2*e*R/hbar*( I_DC + I_RF*np.cos(omega_RF*t) - I_J*(np.sin(phi)) )
#return R*( I_DC + I_RF*np.sin(omega_RF*t) - I_J*(np.sin(phi)) )
# We need an initial value to phi
phi_0 = 0
# Let's try it for 10 periods
N_points = 1000
t = np.linspace(0, 1000, N_points)
t = np.linspace(0, 628, N_points)
hbar = 1.0545718e-34 #m^2kg/s
e = 1.60217662e-19 #C
@ -29,10 +29,26 @@ e = 1.60217662e-19 #C
df = pd.DataFrame(columns=['I_DC','I_RF','V_DC_bar'])
#phi = odeint(phi_dot, phi_0, t, (.5e-3, .5e-3))[:, 0]
for I_DC in [1e-4, .5e-3, 1.e-3, 1.5e-3, 2.e-3, 2.5e-3]:
#for I_DC in [1e-4, .5e-3, 1.e-3, 1.5e-3, 2.e-3, 2.5e-3]:
for I_DC in np.arange(0, 1e-3, 1e-5):
for I_RF in [0., .5e-3, 2.e-3]:
phi = odeint(phi_dot, phi_0, t, (I_DC, I_RF))
I_DC_bar = np.mean(phi[N_points//2:]/t[N_points//2:])
V_DC_bar = hbar/(2*e)*I_DC_bar
N_asymp = N_points//2
I_DC_bar = np.mean(phi[N_asymp:]/t[N_asymp:])
#V_DC_bar = hbar/(2*e)*I_DC_bar
V_DC_bar = I_DC_bar
print("For I_DC =", I_DC, "\t I_RF = ", I_RF, "\twe find V_DC_bar =", V_DC_bar)
df = df.append({'I_DC': I_DC, 'I_RF': I_RF, 'V_DC_bar': V_DC_bar}, ignore_index = True)
df = df.append({'I_DC': I_DC, 'I_RF': I_RF, 'V_DC_bar': V_DC_bar}, ignore_index = True)
## Plotting the thing
plt.figure()
plt.xlabel("$\\overline{V_{DC}}$")
plt.ylabel("$I_{DC}$")
for I_RF in df.I_RF.unique():
x, y = df[df.I_RF == I_RF][["V_DC_bar", "I_DC"]].to_numpy().T
plt.plot(x[10:], y[10:], label="$I_{RF} = " + str(I_RF) + "$")
plt.legend()
plt.show()