Mediating Fully Coherent Dipole-Dipole-Interactions Using Three-Dimensional Atomic Arrays

Katharina Brechtelsbauer, Daniel Malz

Quantum simulators employing cold atoms are among the most promising approaches to tackle quantum many-body problems. Nanophotonic structures are widely employed to engineer the band structure of light and are thus investigated as a means to tune the interactions between atoms placed in their vicinity. A key shortcoming of this approach is that excitations can decay into free photons, limiting the coherence of such quantum simulators. Here, we overcome this challenge by proposing to use a simple cubic three-dimensional array of atoms to produce an omnidirectional band gap for light and show that it enables coherent, dissipation-free interactions between embedded impurities. We show explicitly that the band gaps persist for moderate lattice sizes and finite filling fraction, which makes this effect readily observable in experiment. Our paper paves the way toward analog spin quantum simulators with long-range interactions using ultracold atomic lattices, and is an instance of the emerging field of atomic quantum metamaterials.

Antoine Browaeys

F. Robicheaux

Freya Shah, Taylor L. Patti, Oriol Rubies-Bigordà +1 more

Photon-mediated interactions in subwavelength atomic arrays have numerous applications in quantum science. In this paper, we explore the potential of three-level quantum emitters, or ``impurities'' embedded in a two-dimensional atomic array to serve as a platform for quantum computation. By exploiting the altered behavior of impurities as a result of the induced dipole-dipole interactions mediated by subwavelength arrays, we design and simulate a set of universal quantum gates consisting of the $\sqrt{\text{i}\mathrm{SWAP}}$ and single-qubit rotations. We demonstrate that these gates have very high fidelities due to the long atomic dipole-dipole coherence times, as long as the atoms remain within a proximal range. Finally, we design and simulate quantum circuits leading to the generation of the maximally entangled two-qubit Bell states, as well as the entangled three-qubit Greenberger-Horne-Zeilinger state. These findings establish subwavelength emitter arrays as an alternative platform for quantum computation and quantum simulation.

Shiwen Sun, Yi-Xin Wang, Xiao Liu +1 more

Subwavelength atomic arrays offer a powerful platform for engineering cooperative light-matter interactions and enabling quantum metasurfaces. We demonstrate that a two-dimensional array of three-level atoms operating under electromagnetically induced transparency can function as a tunable dual-band atomic mirror, where two independently controllable reflection bands emerge from the collective optical responses mediated by dipole-dipole interactions. These resonances yield dual reflection bands with asymmetric linewidths, whose spectral positions and bandwidths can be tuned through the control-field parameters, dipole orientation, incident geometry, and lattice constant. We further identify the conditions under which additional diffraction orders emerge, which delineate the operational and tunable range of the atomic mirror via its collective-mode structure. This scheme provides a fully tunable dual-band atomic mirror operating across broad frequency and angular ranges, offering a practical and experimentally accessible pathway toward reconfigurable photonic elements in atomic-array platforms at low energy levels.

Almut Beige, S. F. Huelga, P. L. Knight +2 more