bachelor_thesis/presentation/spin_chain/time_evolution.py

44 lines
910 B
Python

import numpy as np
import matplotlib.pyplot as plt
from pyqcs import State, sample
from transfer_matrix import T_time_slice
from hamiltonian import H
nqbits = 4
g = 0.5
N = 400
t_stop = 9
delta_t = 0.05
qbits = list(range(nqbits))
n_sample = 200
measure = 0b10
results_qc = []
print()
for t in np.arange(0, t_stop, delta_t):
# QC simulation
state = State.new_zero_state(nqbits)
for _ in range(N):
state = T_time_slice(qbits, t, g, N) * state
result = sample(state, measure, n_sample)
results_qc.append(result[0] / n_sample)
# Simulation using matrices
#np_
print(f"simulating... {int(t/t_stop*100)} % ", end="\r")
print()
print("done.")
plt.plot(np.arange(0, t_stop, delta_t), results_qc)
plt.xlabel("t")
plt.ylabel(r"$|0\rangle$ probability amplitude for second spin")
plt.title(f"{nqbits} site spin chain with g={g} coupling to external field")
plt.show()