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[en] We analyze the operating regimes of a very small optical dipole trap, loaded from a magneto-optical trap, as a function of the atom loading rate, i.e., the number of atoms per second entering the dipole trap. We show that, when the dipole trap volume is small enough, a 'collisional blockade' mechanism locks the average number of trapped atoms on the value 0.5 over a large range of loading rates. We also discuss the 'weak loading' and 'strong loading' regimes outside the blockade range, and we demonstrate experimentally the existence of these three regimes

[en] In this paper we propose and analyze various operating regimes of a quantum phase gate built on two atoms trapped in two independent dipole traps. The gate operates when the atoms are excited using a two-photon transition from the hyperfine manifold of ground states up to Rydberg states with strong dipole-dipole interaction. Experimental requirements are discussed to reach a fast (microsecond) gate operation

[en] In this paper we propose and analyze a feasible scheme where the detection of a single scattered photon from two trapped atoms or ions performs a conditional unitary operation on two qubits. As examples we consider the preparation of all four Bell's states, the reverse operation that is a Bell's measurement, and a controlled-NOT (CNOT) gate. We study the effect of atomic motion and multiple scattering by evaluating Bell's inequalities violations and by calculating the CNOT gate fidelity