Overview of examples

In addition to the detailed tutorials, InQuanto contains several example scripts showing how various functionality is used. In this file we provide a broad overview of the intention of each example, highlighting the functionality that is demonstrated. Examples using the extensions are found elsewhere.

algorithms/adapt

Examples of ADAPT-VQE.

File	Description
algorithm_fermionic_adapt.py	A simulation of H2 in STO-3G using the ADAPT algorithm with fermionic helper functions.
algorithm_adapt.py	A simulation of H2 in STO-3G using the ADAPT algorithm.
algorithm_iqeb.py	A simulation of H2 in STO-3G using IQEB algorithm.

algorithms/qse

Examples of Quantum Subspace Expansion.

File	Description
algorithm_qse.py	A simulation of H2 in STO-3G using the QSE algorithm

algorithms/time_evolution

Examples of time evolution algorithms.

File	Description
vqs_real_example_paper.py	A AlgorithmMcLachlanRealTime time evolution simulation for a small system.
vqs_real_example_paper_phased.py	A custom equation of motion VQS time evolution simulation.
vqs_real_example.py	A AlgorithmMcLachlanRealTime time evolution simulation
vqs_imag_example.py	A AlgorithmMcLachlanImagTime time evolution simulation
imtime_evolution_example.py	An exact imaginary time evolution simulation using express methods
time_evolution_example.py	An exact time evolution simulation using express methods

algorithms/vqd

Examples of Variational Quantum Deflation.

File	Description
algorithm_vqd.py	Variational Quantum Deflation using computables.

algorithms/vqe

Examples of canonical Variational Quantum Eigensolver usage.

File	Description
algorithm_vqe_uccsd.py	A canonical VQE simulation of H2 in STO-3G using a UCCSD Ansatz.
algorithm_vqe_shots_minimizers.py	Use of minimizers in shot-based calculations.
algorithm_vqe_varCI.py	A canonical VQE simulation of H2 in STO-3G using a variational configuration interaction Ansatz.
algorithm_vqe_hea.py	A canonical VQE simulation of H2 in STO-3G using a hardware-efficient Ansatz.

ansatzes

Examples demonstrating usage of Ansatz classes.

File	Description
multiconfigstatebox_6qubit.py	Preparation of a 6 qubit linear combination of fermionic occupation states with fixed coefficients.
multiconfigstate_4qubit.py	Preparation of a 4 qubit linear combination of fermionic occupation states with fixed coefficients.
multiconfigstate_6qubit.py	Preparation of a 6 qubit linear combination of fermionic occupation states with fixed coefficients.
multiconfigstatebox_4qubit.py	Preparation of a 4 qubit linear combination of fermionic occupation states with fixed coefficients.
multiconfig_with_symbols.py	Use of a linear combination of fermionic occupation states as a variational ansatz.
layered_hea.py	Use of a layered hardware efficient Ansatz.
fermion_space_ansatze.py	Use of a general Fermionic Ansatz.

computables

Examples demonstrating usage of computables classes.

File	Description
computable_protocol_tutorial.py	Demonstrates the general use of computables and protocols.

computables/atomic

Examples demonstrating usage of atomic computable classes.

File	Description
computable_h2_symbolic_derivatives.py	Use of computables classes for STO-3G H2 expectation value and gradients with symbolic protocol.
finite_difference.py	An example showing how to use evaluate gradients and compare against finite differences
expval_symbolic.py	Use of symbolic protocol for expectation value.
using_protocol_list.py	An example using protocol list for finite differences
computable_overlap_squared.py	Computable expression example (OverlapSquared)
expval_pauli.py	Protocol observable averaging to calculate expectation values.
derivatives_methods.py	An example showing how to use evaluate gradients
computable_h2.py	Use of computables classes for STO-3G H2 expectation value measurement.
expval_noisy_backend.py	Computable expression example (ExpectationValue)

computables/composite

Examples demonstrating usage of composite computable classes.

File	Description
overlap_matrix.py	Simple overlap matrix calculation.
qcm4_computable.py	Estimating energy using QCM4 computable.
qse_matrices.py	An example running QSE using computables
nonorthogonal_matrices.py	Basic CI calculation with NonOrthogonal computable.

computables/composite/gf

Examples demonstrating usage of Green’s function computable classes.

File	Description
gf_measurenorm_matrix_mbgf_spectral.py	Computation of the full GF matrix of the Hubbard dimer, and plot the spectral function A(omega).
gf_measurenorm_element_shots_1.py	Computation (shots for Lanczos, statevector for ground state) one element of GF of Hubbard dimer.
krylov_-1.py	Example of building your own Lanczos routine, then comparing it to KrylovSubspaceComputable.
krylov_4.py	Example of evaluating LanczosMatrixComputable with sandwiched moments from shot-based protocol.
krylov_1.py	Example of evaluating LanczosMatrixComputable to get tridiagonal matrix for given dimension of Krylov space.
gf_measurenorm_element_shots_2.py	Computation (shots for Lanczos, shots for ground state) one element of GF of Hubbard dimer.
gf_measurenorm_element.py	Noiseless statevector computation of one element of GF of Hubbard dimer by sandwiching Hamiltonian moments.
gf_measurenorm_matrix_mbgf.py	Computation (noiseless statevector) the full GF matrix of the Hubbard dimer at a single frequency.
krylov_3.py	Example of evaluating KrylovSubspaceComputable with sandwiched moments from shot-based protocol.
gf_measurenorm_matrix_mbgf_spectral_shots.py	Computation of the full GF matrix of the Hubbard dimer with shots, and plot the spectral function A(omega).
gf_measurenorm_matrix_mbgf_circuits.py	Generation of the circuits required for the full GF matrix of the Hubbard dimer.
krylov_2.py	Use of KrylovSubspaceComputable to get Green’s function element from shot-based protocol from 1st Lanczos vector.
krylov_0.py	Example of evaluating LanczosCoefficientsComputable to get elements of tridiagonal matrix.

computables/composite/rdm

Examples demonstrating usage of reduced density matrix computable classes.

File	Description
rdm_computable.py	An example for constructing an RDM using computables
rdm_nevpt2.py	Test of NEVPT2 using RDMs from

computables/primitive

Examples demonstrating usage of primitive computable classes.

File	Description
basic_primitives.py	An example showing how to use quantum computables.

core

Examples demonstrating usage of logging and debugging functionality.

File	Description
context_printing.py	Using context for logging standard outputs
symbols.py	Simple demonstrations of manipulating Symbols and SymbolDict in inquanto

embeddings

Examples of usage of embedding methods.

File	Description
dmet_one_h2x3_express_hf.py	One-shot DMET calculations on hydrogen rings.
dmet_full_h2x3_express_hf.py	Full DMET calculations on hydrogen rings.
dmet_one_h2x3_express_vqe.py	One-shot DMET calculations on hydrogen rings
impurity_dmet_h2x3_express_vqe.py	An example impurity DMET simulation of a 3-dihydrogen ring using the express module.

express

Examples of usage of the built-in example molecular data in InQuanto.

File	Description
h5_operations.py	Built-in example molecular data.
get_started_express.py	Basic code snippets to use express, operators and states.

mappings

Examples of fermion-qubit mapping functionality.

File	Description
mapping_jw.py	Use of the Jordan-Wigner mapping from fermions to qubits.
mapping_bk.py	Use of the Bravyi-Kitaev mapping from fermions to qubits.
mapping_paraparticular.py	Use and comparison of the paraparticle mapping from fermions to qubits

minimizers

Examples of classical minimizers in InQuanto.

File	Description
minimizers.py	Use of minimizers.
integrators.py	Symbolic evaluation and comparing integrator methods.

operators

Examples of functionality of operator and state classes.

File	Description
fermion_state.py	Creation of FermionState objects and demonstration of some functionality.
fermion_operator.py	Examples of some FermionOperator methods.
orbital_optimizer.py	Orbital optimization using Pipek-Mezey as an example.
double_factorization_h2.py	Simple energy calculation using a double factorized hamiltonian.
qubit_state.py	Construction of QubitState and demonstration of some functionality.
orbital_transformer.py	Orbital transformation methods.
chemistry_integral_operators.py	Creation of ChemistryRestrictedIntegralOperator (CRIO) and conversion to FermionOperator.
qubit_operator.py	Construction of QubitOperator and demonstration of some functionality.

protocols

Examples demonstrating usage of protocol classes.

File	Description
phase_shift_df_grad_expr.py	Use of phase shift derivative for STO-3G H2 expectation value measurement.
feature_projective_measurements.py	Example using a simple ProjectiveMeasurements protocol.
factorized_overlap.py	Calculating complex overlaps with the FactorizedOverlap protocols and comparing to HadamardTestOverlap.
expval_spam.py	Running PauliAveraging with inquanto’s noise mitigation.
feature_partition_strategy.py	Partition measurement reduction strategies for PauliAveraging protocol.
phase_shift_df_grad_hea.py	Use of phase shift derivative for STO-3G H2 expectation value measurement.
expval_mitigation_methods+qermit.py	Running protocols via Qermit’s MitRes and MitEx and inquanto’s noise mitigation.
feature_credits_cost.py	Protocol observable averaging to calculate expectation values.
hadamard_test_overlap.py	Calculating complex overlaps with the HadamardTestOverlap protocol.
pauli_hadamard_protocols.py	Usage of the PauliAveraging and HadamardTest protocols.
expval_pmsv.py	Example using PMSV error mitigation to calculate expectation values.
hadamard_direct_df_grad_expr.py	Use of phase shift derivative for STO-3G H2 expectation value measurement.
qermit_spam_zne.py	Running protocols via Qermit’s MitRes and MitEx.
overlap_squared_protocols.py	Compare different shot based protocols for calculating an overlap squared.
feature_observable_averaging.py	Protocol observable averaging to calculate expectation values.

protocols/phase_estimation

Examples demonstrating usage of the quantum phase estimation protocols.

File	Description
hadamard_test_iqpe_statevector.py	Demonstration of the generation of IPEA unitaries for statevector simulation.
hadamard_test_iqpe_quantinuum.py	Demonstration of the generation of IPEA circuits with the specialized Quantinuum protocols.
hadamard_test_iqpe.py	Demonstration of the generation of IPEA circuits, and their use for Hadamard test sampling.

spaces

Examples of space classes for generating operators and states.

File	Description
parafermion_space.py	Use of ParaFermionSpace objects to generate parafermionic states and operators.
fermion_spaces.py	Use of FermionSpace objects to generate fermionic states and operators, including point group symmetry.
qubit_spaces.py	Use of QubitSpace object to generate qubit operators.

symmetry

Examples of symmetry classes and functionality.

File	Description
qubit_tapering.py	Qubit tapering - operators and Ansatzae.
qubit_symmetry_operators.py	Finding qubit Z2 symmetry operators.
fermionic_symmetry_operators.py	Finding fermionic Z2 symmetry operators.
point_group.py	Use of PointGroup class containing point group symmetry information.