我尝试运行以下哈密顿量的代码：

H = $\sum_{i<j} J_{ij}(\sigma_i^+ \sigma_j^- + \sigma_i^- \sigma_j^+) + \sum_j(B + B_j)\sigma_j^z$

字符串
代码如下所示：

import numpy as np
import qutip as qt
from scipy.constants import hbar

# Qubit-qubit coupling matrix:

alpha = 1.47
constant = 67.3765

def create_matrix(rows, columns):
    matrix = []
    for i in range(rows):
        row = []
        for j in range(columns):
            if i == j:
                entry = 0
                row.append(entry)
            else:
                entry = constant*np.power(abs(i - j), -alpha)
                row.append(entry)
        matrix.append(row)
    return matrix

num_qubits = 8

J_ij = create_matrix(num_qubits, num_qubits)
J_ij = np.matrix(J_ij)

# Magnetic field:

B_i = np.array([[2.85884931, 26.22601547, 48.5376065, 62.948092,
                 53.7557919, 37.31269595, 10.50862743, 0.1]])

B = 15707.96326795

# Hamiltonian:
# Define the spin operators for each ion
spin_operators = [qt.jmat(0.5, 'x'), qt.jmat(0.5, 'y'), qt.jmat(0.5, 'z')]

# Define the raising and lowering operators for each ion
s_plus = [qt.tensor([qt.qeye(2)] * i + [qt.create(2)] + [qt.qeye(2)] * (num_qubits - i - 1)) for i in range(num_qubits)]
s_minus = [qt.tensor([qt.qeye(2)] * i + [qt.destroy(2)] + [qt.qeye(2)] * (num_qubits - i - 1)) for i in range(num_qubits)]
s_z = [qt.tensor([qt.qeye(2)] * i + [spin_operators[0]] + [qt.qeye(2)] * (num_qubits - i - 1)) for i in range(num_qubits)]

# XY interaction term
interaction_term = sum([J_ij[i, j] * (s_plus[i] * s_minus[j] + s_minus[i] * s_plus[j]) for i in range(num_qubits-1) for j in range(i+1, num_qubits)])

# Transverse magnetic field term
#transverse_field_term = hbar*B * sum(s_z)
transverse_field_term = B*sum(s_z)

# Define the Hamiltonian
H = interaction_term + transverse_field_term
H = H.full()

型
我提供完整的代码，所以它是可复制的。问题出在我需要修改的transverse_field_term = B*sum(s_z)行上。我之前使用H = $\sum_{i<j} J_{ij}（\sigma_i^+ \sigma_j^- + \sigma_i^- \sigma_j^+）+ B\sum_j\sigma_j^z$，但最后一项现在是\sum_j(B + B_j)\sigma_j^z，我试图在代码中将其写为：

# Transverse magnetic field term
transverse_field_term = sum((B + B_i[i]) * s_z[i] for i in range(num_qubits))

型
但我得到了以下错误：

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
 42 # Transverse magnetic field term
---> 43 transverse_field_term = sum((B + B_i[i]) * s_z[i] for i in range(num_qubits))
     45 # Define the Hamiltonian

<ipython-input-11-c550e8be0fe1> in <genexpr>(.0)
     41 
     42 # Transverse magnetic field term
---> 43 transverse_field_term = sum((B + B_i[i]) * s_z[i] for i in range(num_qubits))
     44 
     45 # Define the Hamiltonian

~/.virtualenvs/cgan_tf/lib/python3.10/site-packages/qutip/qobj.py in __rmul__(self, other)
     633                 return out
    634             else:
--> 635                 return other * self.data
    636 
    637         elif isinstance(other, list):

 ~/.virtualenvs/cgan_tf/lib/python3.10/site-packages/scipy/sparse/_base.py in      __rmul__(self, other)
    618 
    619     def __rmul__(self, other):  # other * self
--> 620         return self._rmul_dispatch(other)
    621 
    622     #######################

~/.virtualenvs/cgan_tf/lib/python3.10/site-packages/scipy/sparse/_base.py in _rmul_dispatch(self, other)
    612             except AttributeError:
    613                 tr = np.asarray(other).transpose()
--> 614             ret = self.transpose()._mul_dispatch(tr)
    615             if ret is NotImplemented:
    616                 return NotImplemented

~/.virtualenvs/cgan_tf/lib/python3.10/site-packages/scipy/sparse/_base.py in _mul_dispatch(self, other)
    557             # dense row or column vector
    558             if other.shape != (N,) and other.shape != (N, 1):
--> 559                 raise ValueError('dimension mismatch')
    560 
    561             result = self._mul_vector(np.ravel(other))

ValueError: dimension mismatch

型
我试着用

# Reshape B_i to match the shape of s_z
B_i_reshaped = np.reshape(B_i, (num_qubits, 1))

# Transverse magnetic field term
transverse_field_term = -B * sum((B_i_reshaped[i] + B) * s_z[i] for i in range(num_qubits))

型
但我得到了同样的错误。
我该怎么弥补？