Calculation of one site expectation values

class varipeps.expectation.one_site.One_Site_Expectation_Value(gates: Sequence[jax.Array])

__call__(peps_tensors: Sequence[Array], unitcell: PEPS_Unit_Cell, *, normalize_by_size: bool = True, only_unique: bool = True) → Array | List[Array]

Calculate the expectation value for PEPS unitcell depending on the gates set in the class.

Parameters:

peps_tensors (sequence of jax.numpy.ndarray) – The sequence of unique PEPS tensors in the unitcell.
unitcell (PEPS_Unit_Cell) – The PEPS unitcell.
spiral_vectors (single or sequence of jax.numpy.ndarray) – If the expectation value is for a spiral iPEPS ansatz, in this argument the wavevectors are expected.

Keyword Arguments:

normalize_by_size (bool, optional) – Flag if the expectation value should be normalized by the number of tensors in the unitcell.
Default: True
only_unique (bool, optional) – Flag if the expectation value should be calculated just once for each unique PEPS tensor in the unitcell.
Default: True

Returns:

The expectation values for all gates. Single tensor if only one gate is applied.

Return type:

jax.numpy.ndarray or list of jax.numpy.ndarray

varipeps.expectation.one_site.calc_one_site_multi_gates(peps_tensor: Array, peps_tensor_obj: PEPS_Tensor, gates: Sequence[Array]) → List[Array]

Calculate the one site expectation values for a PEPS tensor and its environment.

Parameters:

peps_tensor (jax.numpy.ndarray) – The PEPS tensor array. Have to be the same object as the tensor attribute of the peps_tensor_obj argument.
peps_tensor_obj (PEPS_Tensor) – PEPS tensor object.
gates (sequence of jax.numpy.ndarray) – Sequence with the gates which should be applied to the PEPS tensor.

Returns:

List with the calculated expectation values of each gate.

Return type:

list of jax.numpy.ndarray

varipeps.expectation.one_site.calc_one_site_multi_gates_obj(peps_tensor_obj: PEPS_Tensor, gates: Sequence[Array]) → List[Array]

Calculate the one site expectation values for a PEPS tensor and its environment.

This function just wraps calc_one_site_multi_gates.

Parameters:

peps_tensor_obj (PEPS_Tensor) – PEPS tensor object.
gates (sequence of jax.numpy.ndarray) – Sequence with the gates which should be applied to the PEPS tensor.

Returns:

List with the calculated expectation values of each gate.

Return type:

list of jax.numpy.ndarray

varipeps.expectation.one_site.calc_one_site_single_gate(peps_tensor: Array, peps_tensor_obj: PEPS_Tensor, gate: Array) → Array

Calculate the one site expectation values for a PEPS tensor and its environment.

This function just wraps calc_one_site_multi_gates.

Parameters:

peps_tensor (jax.numpy.ndarray) – The PEPS tensor array. Have to be the same object as the tensor attribute of the peps_tensor_obj argument.
peps_tensor_obj (PEPS_Tensor) – PEPS tensor object.
gates (jax.numpy.ndarray) – Gate which should be applied to the PEPS tensor.

Returns:

Expectation value for the gate.

Return type:

jax.numpy.ndarray

varipeps.expectation.one_site.calc_one_site_single_gate_obj(peps_tensor_obj: PEPS_Tensor, gate: Array) → Array

Calculate the one site expectation values for a PEPS tensor and its environment.

This function just wraps calc_one_site_single_gate.

Parameters:

peps_tensor_obj (PEPS_Tensor) – PEPS tensor object.
gates (jax.numpy.ndarray) – Gate which should be applied to the PEPS tensor.

Returns:

Expectation value for the gate.

Return type:

jax.numpy.ndarray