openfermion.circuits.trotter_steps_required_propagator

Determine the number of Trotter steps for accurate state evolution.

openfermion.circuits.trotter_steps_required_propagator(
    trotter_error_bound, time, prop_precision
)

This function calculates the number of steps required to bound the error in the time evolution operator (propagator error / spectral norm error) to a given fidelity precision. This is appropriate for quantum dynamics applications where we care about the accuracy of the state itself over time. This uses the following definition of error for time t and number of steps r:

\[ \lVert U - U^{TS} \rVert = \frac{t^3}{r^2} E_{bound}(H) \]

trotter_error_bound float

Upper bound on Trotter error in the state of interest.

time float

The total simulation time.

prop_precision float

Acceptable error in the time evolution operator (propagator error).

The integer minimum number of Trotter steps required.