Atom-by-atom assembly of defect-free one-dimensional cold atom arrays

Abstract

The realization of large-scale fully controllable quantum systems is an exciting frontier in modern physical science. We use atom-by-atom assembly to implement a novel platform for the deterministic preparation of regular arrays of individually controlled cold atoms. In our approach, a measurement and feedback procedure eliminates the entropy associated with probabilistic trap occupation and results in defect-free arrays of over 50 atoms in less than 400 ms. The technique is based on fast, realtime control of 100 optical tweezers, which we use to arrange atoms in desired geometric patterns and to maintain these configurations by replacing lost atoms with surplus atoms from a reservoir. This bottom-up approach enables controlled engineering of scalable many-body systems for quantum information processing, quantum simulations, and precision measurements.The detection and manipulation of individual quantum particles, such as atoms or photons, is now routinely performed in many quantum physics experiments [1,2]; however, retaining the same control in large-scale systems remains an outstanding challenge. For example, major efforts are currently aimed at scaling up ion-trap and superconducting platforms, where high-fidelity quantum computing operations have been demonstrated in registers consisting of several qubits [3,4]. In contrast, ultracold quantum gases composed of neutral atoms offer inherently large system sizes. However, arbitrary single atom control is highly demanding and its realization is further limited by the slow evaporative cooling process necessary to reach quantum degeneracy. Only in recent years has individual particle detection [5,6] and basic single-spin control [7] been demonstrated in low entropy optical lattice systems.This Report demonstrates a novel approach for rapidly creating scalable quantum matter with inherent single particle control via atom-by-atom assembly of large defect-free arrays of cold neutral atoms [8,9]. We use optical microtraps to directly extract individual atoms from a laser-cooled cloud [10][11][12] and employ recently demonstrated trapping techniques [13][14][15][16][17] and single-atom position control [18][19][20][21][22] to create desired atomic configurations. Central to our approach is the use of single-atom detection and real-time feedback [18,21,22] to eliminate the entropy associated with the probabilistic trap occupation [11] (currently limited to ninety percent even with advanced loading techniques [23][24][25]). Related to the fundamental concept of "Maxwell's demon" [8,9], this method allows us to rapidly create large defect-free atom arrays and to maintain them for long periods of time, providing an excellent platform for large-scale experiments based on techniques ranging from Rydberg-mediated interactions [26][27][28][29][30] to nanophotonic platforms [31,32] and Hubbard model physics [16,17,33].The experimental protocol is illustrated in Fig. 1A. The trap array is produced by an acousto-optic deflector (AOD) and imaged with a 1:1 telescope onto a 0.5 NA...

Discrete Time Crystals: Rigidity, Criticality, and Realizations

“…We emphasize that our proposed realization can likewise be naturally implemented in ultracold polar molecules [45,46] and Rydberg-dressed neutral atom arrays [47,48], both of which also feature long-range interactions. This leads to a key question: can the discrete time crystal survive the presence of such long-range interactions [49][50][51]?…”

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).…”

Quantum simulators by design: Many-body physics in reconfigurable arrays of tunnel-coupled traps

“…2) The dynamic control over local potential depths can be utilized for Floquet engineering [33,41] with modulation frequencies of up to 10 kHz, fully adjustable modulation amplitudes, and single-site addressability. 3) A promising alternative to the loading schemes starting with BECs arises from the implementation of Raman side-band cooling in individual traps [11,12] with the targeted many-body state assembled atom by atom [15][16][17] out of the low entropy Mott-insulator phase. This facilitates studies of the many-body physics of atomic species, which are not accessible to BEC, or arbitrary mixtures of species.…”

“…Compared to state of the art holographic trap arrays generated by phase modulating spatial light modulators [15,17], it accesses the tunneling regime and omits pixelation constraints imposed to trap spacing, homogeneity and system size. With regard to potentials generated by acousto-optics through multi-tone synthesis [16] or time-averaging [22], it is scalable and avoids additional heating.…”

“…In combination with acoustooptic deflectors and spatial light modulators (SLM) this approach has been extended to few-well configurations showing tunnel-coupling [13,14] on one side and the deterministic preparation of larger defect-free 1D and 2D arrays with spacing too large for tunneling on the other side [15][16][17].…”