Enhancing survival resonances with engineered dissipation

Abstract

We investigate a scheme that enhances survival resonances in a δ-killed system through actively recycling lost atoms. The process causes atoms to dissipate into superpositions of momentum states with sustained survival when exposed to kicks of a dissipative optical standing wave. The recycling process causes momentum redistribution, which gives the atoms multiple chances to enter a long-surviving mode. The survival resonance peak height shows an improvement of a factor of 2.4. This technique can increase the sensitivity and precision of atomic interferometers based on survival resonances.

Classical model for survival resonances close to Talbot time

“…experiments [14][15][16]. Furthermore, our model offers an intuitive picture of the quantum mechanical diffraction from imaginary potentials based on trajectories in phase space.…”

“…Γ describes the decay rate of the upper state, and we assume that when the atom in the excited state spontaneously decays it is lost and not further considered in the experiment. For the experimental realisation of the AOKR [14][15][16] the ground state has two levels, with only one of them considered here. The dominating decay channel goes into the second level [14] that motivates our approximation.…”

“…( 8)). Throughout this work we use the experimentally relevant parameters [14][15][16] k l = 2π/780nm, Γ = 2π6MHz, Ω = 2Γ, N = 7 kicks, t = 500ns, and M the mass of an 85 Rb atom, unless otherwise stated. We see in the figure that the -classical model captures the quantum dynamics well.…”

“…The latter is used to implement the atom-optics kicked rotor, a standard model of classical as well as quantum dynamical systems' theory [10][11][12][13]. A series of recent experiments [14][15][16] applied instead an absorption grating to induce pulses on cold rubidium atoms, realizing an atom-optics "killed" rotor (AOKR), implying the loss of atoms due to resonant absorption. The corresponding potential is imaginary describing the dissipative process.…”

Quantum to Classical Walk Transitions Tuned by Spontaneous Emissions

“…We also confirm the SE events lead to a biased momentum distribution, which agrees well with our numerical simulations. Our findings demonstrate a scheme to control the robustness of quantum walks and can also be applied to other cold atom experiments involving spontaneous emissions [18,19].…”