dq.constant

constant(qarray: QArrayLike) -> ConstantTimeQArray

Instantiate a constant timeqarray.

A constant timeqarray is defined by \(O(t) = O_0\) for any time \(t\), where \(O_0\) is a constant qarray.

Parameters:

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

  Constant qarray \(O_0\).

Returns:

• (timeqarray of shape (..., n, n) when called) –

  Callable returning \(O_0\) for any time \(t\).

Examples:

>>> H = dq.constant(dq.sigmaz())
>>> H(0.0)
QArray: shape=(2, 2), dims=(2,), dtype=complex64, layout=dia, ndiags=1
[[ 1.+0.j    ⋅   ]
 [   ⋅    -1.+0.j]]
>>> H(1.0)
QArray: shape=(2, 2), dims=(2,), dtype=complex64, layout=dia, ndiags=1
[[ 1.+0.j    ⋅   ]
 [   ⋅    -1.+0.j]]