LieTrotter
class qiskit.synthesis.LieTrotter(reps=1, insert_barriers=False, cx_structure='chain', atomic_evolution=None, wrap=False)
Bases: ProductFormula
The Lie-Trotter product formula.
The Lie-Trotter formula approximates the exponential of two non-commuting operators with products of their exponentials up to a second order error:
In this implementation, the operators are provided as sum terms of a Pauli operator. For example, we approximate
References
[1]: D. Berry, G. Ahokas, R. Cleve and B. Sanders, “Efficient quantum algorithms for simulating sparse Hamiltonians” (2006). arXiv:quant-ph/0508139 [2]: N. Hatano and M. Suzuki, “Finding Exponential Product Formulas of Higher Orders” (2005). arXiv:math-ph/0506007
The ‘Callable[[Pauli | SparsePauliOp, float], QuantumCircuit]’ signature of the ‘atomic_evolution’ argument is pending deprecation as of qiskit 1.2. It will be marked deprecated in a future release, and then removed no earlier than 3 months after the release date. Instead you should update your ‘atomic_evolution’ function to be of the following type: ‘Callable[[QuantumCircuit, Pauli | SparsePauliOp, float], None]’.
Parameters
- reps (int) – The number of time steps.
- insert_barriers (bool) – Whether to insert barriers between the atomic evolutions.
- cx_structure (str) – How to arrange the CX gates for the Pauli evolutions, can be
"chain", where next neighbor connections are used, or"fountain", where all qubits are connected to one. This only takes effect whenatomic_evolution is None. - atomic_evolution (Callable[[Pauli |SparsePauliOp, float], QuantumCircuit] | Callable[[QuantumCircuit, Pauli |SparsePauliOp, float], None] | None) – A function to apply the evolution of a single
Pauli, orSparsePauliOpof only commuting terms, to a circuit. The function takes in three arguments: the circuit to append the evolution to, the Pauli operator to evolve, and the evolution time. By default, a single Pauli evolution is decomposed into a chain ofCXgates and a singleRZgate. Alternatively, the function can also take Pauli operator and evolution time as inputs and returns the circuit that will be appended to the overall circuit being built. - wrap (bool) – Whether to wrap the atomic evolutions into custom gate objects. This only takes effect when
atomic_evolution is None.
Attributes
settings
Return the settings in a dictionary, which can be used to reconstruct the object.
Returns
A dictionary containing the settings of this product formula.
Raises
NotImplementedError – If a custom atomic evolution is set, which cannot be serialized.
Methods
synthesize
synthesize(evolution)
Synthesize an qiskit.circuit.library.PauliEvolutionGate.
Parameters
evolution (PauliEvolutionGate) – The evolution gate to synthesize.
Returns
A circuit implementing the evolution.
Return type