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Numerically upper bound the error in the ground state energy for the second order Trotter-Suzuki expansion.
openfermion.circuits.error_bound( terms, tight=False )
||a list of single-term QubitOperators in the Hamiltonian to be simulated.|
||whether to use the triangle inequality to give a loose upper bound on the error (default) or to calculate the norm of the error operator.|
|A float upper bound on norm of error in the ground state energy.|
Notes: follows Poulin et al.'s work in "The Trotter Step Size Required for Accurate Quantum Simulation of Quantum Chemistry". In particular, Equation 16 is used for a loose upper bound, and the norm of Equation 9 is calculated for a tighter bound using the error operator from error_operator.
Possible extensions of this function would be to get the expectation value of the error operator with the Hartree-Fock state or CISD state, which can scalably bound the error in the ground state but much more accurately than the triangle inequality.