LayerModel
class LayerModel(L, H2, H1=None, cyclic=False, keep_only_odd=None)
Bases: LocalHam1D
A model for representing a layer of time-evolution interactions.
Essentially, this class is a simple wrapper of quimb.tensor.LocalHam1D. Its main purpose is to provide a simple interface for constructing a Quimb-compatible Hamiltonian from Qiskit objects.
Initialize a LayerModel instance.
Most of the arguments below are simply forwarded to quimb.tensor.LocalHam1D so check out its documentation for more details.
Parameters
- L – the number of qubits.
- H2 – the two-site interactions.
- H1 – the optional on-site interactions.
- cyclic – whether to apply periodic boundary conditions.
- keep_only_odd – whether to keep only odd bond interactions. For more details see
keep_only_odd.
Attributes
keep_only_odd
Whether to keep only interactions on bonds with odd indices.
Methods
from_quantum_circuit
classmethod from_quantum_circuit(circuit, *, scaling_factor=1.0, keep_only_odd=None, **kwargs)
Construct a LayerModel from a QuantumCircuit.
You can see an example of this function in action in the docs of quimb_layers.
Parameters
- circuit (QuantumCircuit) – the quantum circuit to parse.
- scaling_factor (float) – a factor with which to scale the term strengths. This can be used to apply (for example) a time step scaling factor. It may also be used (e.g.) to split onsite terms into two layers (even and odd) with $0.5$ of the strength, each.
- keep_only_odd (bool | None) – the value to use for
keep_only_odd. - kwargs – any additional keyword arguments to pass to the
LayerModelconstructor.
Returns
A new LayerModel instance.
Raises
NotImplementedError – if an unsupported quantum gate is encountered.
Return type
get_gate_expm
get_gate_expm(where, x)
Get the local term at the sites where, matrix exponentiated by x.
If where applies to an even bond index and keep_only_odd is True, this method will return None.
Parameters
- where (tuple[int, int]) – the pair of site indices of the local term to get. This identifies the bond index.
- x (float) – the value with which to matrix exponentiate the interaction term.
Returns
The interaction in terms of an array or None depending on keep_only_odd (see above).
Return type
ndarray | None