#!/bin/env python3 import numpy as np from scipy.integrate import odeint from matplotlib import pyplot as plt 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 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)) ) # 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) hbar = 1.0545718e-34 #m^2kg/s 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_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 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)