There is presented a method for outputting at least first and second electromagnetic, EM, signals for respectively interacting with spatially separated first and second matter particles in an interaction region. The matter particles act as qubits for use with a quantum computation. The interaction of the EM signals with the qubits is associated with a Hamiltonian operator comprising at least a first and a second element. EM radiation is generated using an EM source. The EM radiation is modulated by the with a first modulator configured to temporally modulate the EM radiation within a computation time period. The first modulator is associated with the first element of the Hamiltonian operator. The EM radiation is modulated with a second modulator configured to modulate the EM radiation such that the first EM signal is spatially separate to the second EM signal in the interaction region. The second modulator is associated with the second element of the Hamiltonian operator. The one or more EM signals are output based on the modulated EM radiation, to the plurality of matter particles.