dq.braket

braket(x: QArrayLike, y: QArrayLike) -> Array

Returns the inner product \(\braket{\psi|\varphi}\) between two kets.

Parameters:

• x (qarray-like of shape (..., n, 1)) –

  Left-side ket.

• y (qarray-like of shape (..., n, 1)) –

  Right-side ket.

Returns:

• (array of shape (...)) –

  Complex-valued inner product.

Examples:

>>> fock0 = dq.fock(3, 0)
>>> fock01 = (dq.fock(3, 0) + dq.fock(3, 1)).unit()
>>> dq.braket(fock0, fock01)
Array(0.707+0.j, dtype=complex64)