Dynamics and quantum correlations in two independently driven Rydberg atoms with distinct laser fields

Abstract

We study the population dynamics in a two-atom setup in which each atom is driven independently by different light fields, but coupling the same Rydberg state. In particular, we look at how an offset in the Rabi frequencies between two atoms influences the dynamics. We find novel features such as amplifying the Rabi frequency of one atom, together with strong Rydberg-Rydberg interactions freezes the dynamics in the second atom. We characterize the Rydberg-biased freezing phenomenon in detail, with effective Hamiltonians obtained for various limits of the system parameters. In the absence of Rabi-offset, the doubly excited state population exhibits a Lorentzian profile as a function of interaction, whereas for very small offsets it shows splitting and thus peaks. Using an effective Hamiltonian as well as the perturbation theory for weak interactions, we show that the peak arises from a competition between Rabi-offset and Rydberg-Rydberg interactions when both are sufficiently small, together with the Rydberg blockade at large interactions. The effective Hamiltonians provide us with analytical results which are in an excellent agreement with full numerical solutions. Also, we analyze the growth and the dynamics of quantum correlations such as entanglement entropy and quantum discord for the coherent dynamics. We extend our studies to the dissipative case in which the spontaneous emission from the Rydberg state is taken into account and in particular, we look at the purity and quantum discord of the steady states. To conclude, our studies reveal that the local manipulation of an atom using Rabi-offset can be an ideal tool to control the quantum correlations and in general, quantum states of the composite two-qubit systems.

Population trapping in a pair of periodically driven Rydberg atoms

“…Further, using e ±iV 0 k jσ k ee t = k j σ k ee (e ±itV 0 − 1) + I , where I is the identity operator, we rewrite the Hamiltonian in Eq. (2) aŝ ee describes the correlated Rabi coupling [44,76]. The correlated Rabi process is analogous to the density assisted inter-band tunneling or density-dependent hopping for atoms in optical lattices [77,78].…”

Landau-Zener transitions and adiabatic impulse approximation in an array of two Rydberg atoms with time-dependent detuning

“…Therefore, for vanishing interactions the two atom setup converges to a three level bow-tie LZ model [3,4,102,103]. The same two atom setup can mimic a four level bow-tie model if an offset in Rabi frequencies or detunings is provided between two atoms [18,104]. For sufficiently large V 0 (blockade regime), the avoided level crossings form a triangular geometry [see Fig.…”

Population trapping in a pair of periodically driven Rydberg atoms

“…where the operator X = σ1 eg σ2 ee + σ2 eg σ1 ee describes the correlated Rabi coupling [42,72]. The correlated Rabi process is analogous to the density assisted inter-band tunneling or density-dependent hopping for atoms in optical lattices [73,74].…”