# fqe.diagonal_hamiltonian.Diagonal

One-body diagonal Hamiltonian class. Diagonal Hamiltonians are defined as

Inherits From: Hamiltonian

those that are diagonal in the Slater determinant space, namely,

.. math:: \langle I|\hat{H}|J\rangle = pI \delta{IJ}

where I and J are Slater determinants, and p is some phase. Generally such Hamiltonians can be written as

.. math:: \hat{H} = = E_0 + \sumr h{rr} a_r^\dagger a_r

## Methods

### calc_diag_transform

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Performs a unitary digaonlizing transformation of the one-body term and returns that transformation.

### conserve_number

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Returns True if the Hamiltonian is number conserving, else False.

### diag_values

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Returns the diagonal values packed into a single dimension.

### diagonal

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Returns whether or not the Hamiltonian is diagonal.

### diagonal_coulomb

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Returns True if the Hamiltonian is diagonal coloumb, else False.

### dim

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Returns the orbital dimension of the Hamiltonian arrays.

### e_0

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Returns the scalar potential of the Hamiltonian.

### iht

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Returns the matrices of the Hamiltonian prepared for time evolution.

Args
time The time step.

### quadratic

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Returns whether or not the Hamiltonian is quadratic.

### rank

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Returns the rank of the largest tensor.

### tensors

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Returns all tensors in order of their rank.

### transform

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Tranform the one body term using the provided matrix.

Args
trans Unitary transformation.

Returns
Transformed one-body Hamiltonian as a numpy.ndarray.

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