Quantum Computing, Quantum Physics, Quantum Mechanics, Algorithms.
functions with expansion coefficients a_i may be used. To this extent, the variational principle states that: E[a_i] ≥ E0 is the lowest energy eigenstate (ground state) of the Hamiltonian H. E[a_i] = E0 if and only if |Y> is exactly equal to wavefunction corresponding to the lowest energy (ground