Given $$F=-\nabla_eU(e_n, E_n, p_n)$$ The function U is defined at $U(e_n, E_n, p_n) = p_n e_n + (E_n - 0.5 e_n) e_n$
$e_n$, $E_n$, and $p_n$ are all scalar values the system.
In the above equation, I don't understand the context of the negative gradient. Not sure where else to ask so just wondering if someone could explain what those symbols mean here?
$F = -grad(V)$
Negative gradient tells us that the direction of force generated due to this potential is from point with higher potential to point associated with low potential along path with maximum rate of change.