Rapid Production of Uniformly Filled Arrays of Neutral Atoms

Abstract

We demonstrate rapid loading of a small array of optical tweezers with a single 87 Rb atom per site. We find that loading efficiencies of up to 90% per tweezer are achievable in less than 170 ms for traps separated by more than 1.7 µm. Interestingly, we find the load efficiency is affected by nearby traps and present the efficiency as a function of the spacing between two optical tweezers. This enhanced loading, combined with subsequent rearranging of filled sites, will enable the study of quantum many-body systems via quantum gas assembly.A frontier in atomic physics is the study of quantum many-body physics on a microscopic scale. Recent experiments have shown the power of microscopy of degenerate quantum gases in optical lattices [1,2]. An exciting prospect is not only imaging quantum gases, but assembling them into a well-known initial configuration from single-atom building blocks and then observing the resulting dynamics with single-atom resolution. Wavelength-scale optical dipole traps, or optical tweezers, are an attractive platform for control of neutral atoms because they allow repositioning of the atoms after state preparation and site-resolved imaging. Using optical tweezers, long-range interactions between neutral atoms have been harnessed via Rydberg blockade [3-5], and it is now possible to observe controlled interactions and interference between bosonic and fermionic atoms placed individually in their motional ground state [6][7][8]. While optical tweezer traps can be scaled to arrays [9][10][11][12], realizing an ordered array with a single atom per trap is difficult and is a problem of long-standing interest [13][14][15][16].Early experiments with optical tweezers demonstrated sub-Poissonian atom-number statistics using light-assisted collisions that rapidly expel pairs of atoms, a process known as collisional blockade [17][18][19][20]. This has become a reliable method to isolate single atoms, as well as the basis for parity imaging in quantum-gas microscopes [1,2,17]. However, the collisional blockade also limits loading efficiencies to approximately 50%, making the probability to uniformly-fill large arrays prohibitively small [18][19][20].Careful studies of light-assisted collisions in optical dipole traps hold promise for realizing deterministic loading of arrays of atoms [16,21]. Light-assisted collisions are successfully described by transitions between molecular potentials that become resonant with the light at specific interatomic separations, R C [ Fig. 1(a)] [22]. In the case of light that is red-detuned from the bare atomic transition, the atoms associate to an attractive potential and can gain a large kinetic energy, leading to loss of both atoms from the trap. Conversely, when the light is blue-detuned, the atoms associate to a repulsive potential where the maximum kinetic energy gained is set by the detuning [23]. This control has been used to preferentially expel single 85 Rb atoms from a trap, enabling the isolation of single atoms with high probability [16,21]. However, open q...

Floquet Symmetry-Protected Topological Phases in Cold-Atom Systems

“…3b). In combination, this points to the fact that the two edge modes are well localized to a single site and behave like an EPR pair.Experimental realization-Both the ESPT and FSPT Hamiltonians can be implemented in a chain of Rydbergdressed alkali-metal atoms [43,44,46,49,50] trapped in a 1D optical lattice or tweezer array [83,84] (Fig. 1).…”

Annulled van der Waals interaction and fast Rydberg quantum gates

“…4(b), where U is the trap depth (see Appendix L). We find that E L drops from 3.0 × 10 −3 to 1.5 × 10 −3 when U increases from 3.5 mK, as realized in [47], to 60 mK. Since attaining U of order a few times 10 mK is feasible for an optical trap [22], atomic separation errors may be suppressed.…”

“…With the trapping geometry of Refs. [46,47], we have estimated the additional contribution E L to the gate error shown in Fig. 4(b), where U is the trap depth (see Appendix L).…”

“…Concerning whether it is possible to trap two neutral atoms as close as the L's chosen in this work, we note that the authors in Ref. [47] created arrays of deeper optical tweezers, where each trap is characterized by U = 73 MHz∼ 3.5 mK and w = 0.71µm, and successfully loaded 87 Rb atoms in small arrays with optical lattice constant as small as 1.7µm.…”

Cooperative Interactions in Lattices of Atomic Dipoles

“…8.9 by randomly removing a proportion of the atoms. Filling efficiency greater than 90% can be achieved [119,120,147,148], which when combined with a trap depth For example, preliminary investigations have shown that other semi-regular lattices (for example the Lieb lattice [117]) may also exhibit mode interferences like the ones observed in the kagome lattice (Chap. 7), further strengthening the theory that the semi-regular nature has something to do with these cooperative modes.…”