Manuel Endres, Hannes Bernien, Alexander Keesling, Harry Levine, Eric R. Anschuetz, Alexandre Krajenbrink, Crystal Senko, Vladan Vuletić, Markus Greiner, Mikhail D. Lukin
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, real-time 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 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, real-time 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 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 platform for the deterministic preparation of regular one-dimensional 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 more than 50 atoms in less than 400 milliseconds. The technique is based on fast, real-time 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 may enable controlled engineering of scalable many-body systems for quantum information processing, quantum simulations, and precision measurements.
Low-entropy arrays of atomic quantum systems in optical tweezers offer unique prospects for fundamental research on few- and many-body systems as well as for extended applications in quantum technology. The significance of this approach relies on the achievable system size, its uniformity, and the rate of qubit allocation. We propel the neutral-atom quantum-technology platform by the rapid assembly of a regular two-dimensional quantum register of up to 1024 atomic qubits, enabled by a novel implementation of intensity-homogenized tweezer arrays and parallelized atom transport. Our highly efficient microoptical architecture modularizes intensity equalization and tweezer patterning in separate functional units, eliminating restrictions that arise for high-power, high-resolution, and large-scale light-field control within a single device. Arrays of precise grid structure, trap depth, and vibrational frequency with more than 3500 sites are demonstrated. Individual sites are interconnected by up to 50 parallelized transport tweezers with intensity and position control in real-time for swift qubit relocation. Multi-tweezer transport enables the operation of target patterns of up to 32 x 32 sites with sustained near-unity filling fraction. These results boost neutral-atom quantum information science above the kiloqubit level.
Large arrays of individually controlled atoms trapped in optical tweezers are a very promising platform for quantum engineering applications. However, deterministic loading of the traps is experimentally challenging. We demonstrate the preparation of fully loaded two-dimensional arrays of up to ~50 microtraps, each containing a single atom and arranged in arbitrary geometries. Starting from initially larger, half-filled matrices of randomly loaded traps, we obtain user-defined target arrays at unit filling. This is achieved with a real-time control system and a moving optical tweezers, which together enable a sequence of rapid atom moves depending on the initial distribution of the atoms in the arrays. These results open exciting prospects for quantum engineering with neutral atoms in tunable two-dimensional geometries.
Abstract A great challenge in current quantum science and technology research is to realize artificial systems of a large number of individually controlled quantum bits for applications in quantum computing and quantum simulation. Many experimental platforms are being explored, including solid-state systems, such as superconducting circuits1 or quantum dots2, and atomic, molecular and optical systems, such as photons, trapped ions or neutral atoms3–7. The latter offer inherently identical qubits that are well decoupled from the environment and could provide synthetic structures scalable to hundreds of qubits or more8. Quantum-gas microscopes9 allow the realization of two-dimensional regular lattices of hundreds of atoms, and large, fully loaded arrays of about 50 microtraps (or ‘optical tweezers’) with individual control are already available in one10 and two11 dimensions. Ultimately, however, accessing the third dimension while keeping single-atom control will be required, both for scaling to large numbers and for extending the range of models amenable to quantum simulation. Here we report the assembly of defect-free, arbitrarily shaped three-dimensional arrays, containing up to 72 single atoms. We use holographic methods and fast, programmable moving tweezers to arrange—atom by atom and plane by plane—initially disordered arrays into target structures of almost any geometry. These results present the prospect of quantum simulation with tens of qubits arbitrarily arranged in space and show that realizing systems of hundreds of individually controlled qubits is within reach using current technology.
Exercising microscopic control over quantum systems is a central theme in modern physics. Neutral-atom quantum simulators leverage this control to explore quantum many-body phenomena by realizing paradigmatic Hamiltonians, such as the Hubbard model, in isolated systems. Advances in single-atom-resolved manipulation and detection have allowed measurements of microscopic correlations in strongly interacting quantum systems. Quantum gas microscopes have successfully approached this from the top down, starting from bulk quantum gases, while optical tweezers offer a complementary bottom-up route based on controlled few-particle systems. Combining these approaches opens a pathway towards assembling many-body systems atom by atom, enabling deterministic control over the initial quantum state. This thesis presents the development of a compact quantum gas microscope for programmable ensembles of fermionic lithium-6. The apparatus integrates laser cooling, magnetic field control, quantum-gas preparation, optical tweezers, projected potentials, and high-resolution imaging around a high-numerical-aperture microscope objective. Evaporative cooling in a crossed optical dipole trap produces degenerate two-component Fermi gases and molecular Bose--Einstein condensates, providing the quantum-degenerate reservoir for subsequent experiments. We demonstrate uniform loading of degenerate fermionic ensembles into programmable two-dimensional tweezer arrays, overcoming reservoir-size limitations by translating the tweezer array across the reservoir. Leveraging fermionic statistics and the resolved motional spectrum, we prepare a singlet pair in the three-dimensional motional ground state of each tweezer trap. Across an 8x8 array, this yields an average single-particle preparation fidelity of 98.47%. We develop a novel approach combining the deterministic preparation with spin- and site-resolved control via global magnetic field gradients and locally projected repulsive potentials to produce arbitrary product state configurations in parallel across all sites. In this way, we achieve programmable assembly of spin--charge product states of up to 128 atoms, with fast experimental cycle times of 3 seconds. Furthermore, we realize a new scheme for simultaneous spin-, site-, and density-resolved imaging of individual lithium-6 atoms. Encoding the spin information in the fluorescence polarization, we resolve the two spin components within a single 20 microsecond exposure, achieving detection fidelities exceeding 98.5%. These capabilities establish a fast route to preparing low-entropy fermionic product states with microscopic control over their initial spin, charge, and motional configuration. Coupling such states through optical lattices or tunnel-coupled tweezers provides a route for initializing far-from-equilibrium many-body systems, with applications to strongly correlated physics, quantum transport and thermalization, and fermionic quantum information processing.
Assembling and maintaining large arrays of individually addressable atoms is a key requirement for continued scaling of neutral-atom-based quantum computers and simulators. In this work, we demonstrate a new paradigm for assembly of atomic arrays, based on a synergistic combination of optical tweezers and cavity-enhanced optical lattices, and the incremental filling of a target array from a repetitively filled reservoir. In this protocol, the tweezers provide microscopic rearrangement of atoms, while the cavity-enhanced lattices enable the creation of large numbers of optical traps with sufficient depth for rapid low-loss imaging of atoms. We apply this protocol to demonstrate near-deterministic filling (99% per-site occupancy) of 1225-site arrays of optical traps. Because the reservoir is repeatedly filled with fresh atoms, the array can be maintained in a filled state indefinitely. We anticipate that this protocol will be compatible with mid-circuit reloading of atoms into a quantum processor, which will be a key capability for running large-scale error-corrected quantum computations whose durations exceed the lifetime of a single atom in the system. Published by the American Physical Society 2024