Quantum computing with perpetually coupled qubits: on-site localization of excitations

We demonstrate that, in a quantum computer with perpetually coupled qubits, all excitations can be confined to their sites (qubits) even without refocusing. The on-site localization is obtained b) constructing a sequence of qubit energies that efficiently suppresses resonant hopping. The time during which a many-excitation state remains strongly localized in an infinite chain can exceed the reciprocal hopping frequency by ≥ 105 already for a moderate bandwidth of qubit energies. The proposed energy sequence is also convenient for performing quantum operations on the qublts.