  We compare the results of ground state and spectroscopic measurements carried
out on superconducting flux qubits which are effective two-level quantum
systems. For a single qubit and for two coupled qubits we show excellent
agreement between the parameters of the pseudospin Hamiltonian found using both
methods. We argue, that by making use of the ground state measurements the
Hamiltonian of N coupled flux qubits can be reconstructed as well at
temperatures smaller than the energy level separation. Such a reconstruction of
a many-qubit Hamiltonian can be useful for future quantum information
processing devices.
