下面是matplotlib annotate + text可以完成的操作：

import matplotlib.pyplot as plt
import numpy as np

fig = plt.figure(figsize=(7, 3))
ax = fig.add_subplot()

xvalues = [0, 1, 2, 3, 4, 5]
xlabels = [r'$t_0 = 2019$', r'$t_0 = 2023$', r'$t_0 = 2048$', r'$t_0 = 2059$', r'$t_0 = 2060$', r'$t_0 = 2066$']
tickheight = 0.1

ax.annotate("", (4, 1), (5, 1), arrowprops={'arrowstyle':'<-', 'shrinkA': 0, 'shrinkB': 0})
ax.plot([4, 4], [1 - tickheight, 1 + tickheight], c='k', lw=1)
ax.plot([5, 5], [1 - tickheight, 1 + tickheight], c='k', lw=1)
ax.text(4.5, 1.1, 'outflow', ha='center', va='baseline')

ax.annotate("", (2, 2), (4, 2), arrowprops={'arrowstyle':'<-', 'shrinkA': 0, 'shrinkB': 0})
ax.plot([2, 2], [2 - tickheight, 2 + tickheight], c='k', lw=1)
ax.plot([4, 4], [2 - tickheight, 2 + tickheight], c='k', lw=1)
ax.text(3, 2.1, 'cancelling', ha='center', va='baseline')

ax.annotate("", (1, 3), (3, 3), arrowprops={'arrowstyle':'<-', 'shrinkA': 0, 'shrinkB': 0})
ax.plot([1, 1], [3 - tickheight, 3 + tickheight], c='k', lw=1)
ax.plot([3, 3], [3 - tickheight, 3 + tickheight], c='k', lw=1)
ax.text(2, 3.1, 'inflow', ha='center', va='baseline')

ax.spines['top'].set_visible(False)
ax.spines['left'].set_visible(False)
ax.spines['right'].set_visible(False)

ax.set_xticks(xvalues)
ax.set_xticklabels(xlabels)

plt.xlim(-0.1, 5.1)
plt.ylim(0, 3.5)

plt.yticks([])

plt.tight_layout()

plt.show()

结果如下所示：