Pasqal Announces Record Commercial Quantum Processor with 300- Quantum Bits!
On September 15, Pasqal, a French neutral-atom quantum computing company, announced the launch of a 324-atom (quantum bit) quantum processor [1], which is probably the largest commercial quantum processor in terms of quantum bit size. This achievement was scientifically validated in the paper "In situ equilibrium for neutral atom loading of large optical tweezer arrays" [2] published in Physical Review A, and confirms that Pasqal is approaching the industrial scale expected by its customers. This research was done in collaboration with the Paris Institute of Optics. The research was previously reported in a pre-printed paper by PhotonBox.
"We are proud to demonstrate once again the extraordinary potential of neutral atom quantum processors. the validation by our scientists proves our quantum processor roadmap that will provide industrial quantum advantages to our customers by 2024," said Georges-Olivier Reymond, President of Pasqal. "
01Number of quantum bits exceeds 300
The loading of a single atom in optical tweezers is random. This means that the probability that a "trap" will be loaded at any given time is certain (mathematically expressed as η). So far, however, the implementation of large defect-free arrays has had to rely on an atom-by-atom assembly process: initially a few tens of atoms were implemented, recently scaled up to the 200-300 atom range, but further applications require scaling up the assembly technique to higher numbers.
In this work, the team reports a simple "in-situ trap-loading equalization technique", which is based on the analysis of the evolution of all captured single-atom fluorescence traces in the array as a function of the overall trap power . The experiment uses an enclosed, ultra-high vacuum compatible 4K cryostat to achieve extremely high vacuum in the instrument, enabling a lifetime of ∼6000 s for the 87Rb atoms captured by the tweezers. This setup greatly improves the assembly efficiency of large arrays, allowing the experimental team to assemble defect-free arrays of over 300 atoms with an unprecedented probability (∼37%).
Sketch of the experimental setup. The inset shows, from bottom to top, the phase diagram used to generate the 23 × 23 square array with a pitch of 5 μm, the atomic fluorescence image of the atoms loaded in the array, and the trap intensity image obtained on a CCD (charge-coupled element) camera for diagnostics.
Efficient assembly of 324-atom arrays. (a) Fluorescence image of a 625-trap (625-trap) array before rearrangement, with a lattice spacing of 5 µm.(b) Fluorescence image of the array after two rearrangement cycles, showing a defect-free 324-atom array. (c) Probability distribution of the number of missing atoms in the target array, showing a high probability of preparing a defect-free array (≈37%).
Finally, the team illustrated the efficiency of the equalization process by studying the rearrangement of large arrays. A fully loaded array with 324 atoms was achieved in an array consisting of 625 traps, while a defect-free array was obtained with a probability distribution of the number of defects of about 37%. For comparison, a defect-free array with 196 atoms could only be achieved with a 3% probability distribution in a room temperature setup and without using the in-situ equalization method.
Although not shown with a picture in the article, the team says that "the experimental setup has been pushed to the limit in terms of laser power: arrays of up to 361 atoms can be assembled. This number can be greatly increased by using optical systems with larger fields of view such as microscope objectives."
The authors further state that a detailed study of these two limits will be the subject of their future work.
02Pasqal's path to neutral atoms
Since its founding in 2019, Pasqal has leveraged decades of optical research "to make it the first company to achieve this breakthrough." Building on France's longstanding academic excellence in cold atom physics, Pasqal is at the forefront of the emerging quantum industry by building quantum processors from neutral atoms in large 2D and 3D arrays.
In Pasqal's processors, neutral atoms are manipulated with extremely high precision by lasers to achieve the high connectivity and unprecedented scale, exceeding 100 quantum bits and approaching the 1000 quantum bit threshold needed for quantum processors. pasqal has been developing a complete computational stack from atomic quantum bits to software tools for efficient operation and integration into major third-party programming environments. Currently, one of the company's quantum computers is in operation and two others are under construction.
A Pasqal engineer stands next to a neutral-atom quantum computer.
"Pasqal's quantum processor is based on an array of neutral atoms interacting in the Riedberg atomic state, an approach that differs from that pursued by existing companies such as IBM and Google, and which we believe offers the fastest path to scale to thousands of high-fidelity quantum bits and achieve quantum superiority in a variety of practical applications." Georges-Olivier Reymond, CEO of Pasqal, stated [3], "We are on track to deliver the first potential use cases related to industrial end-users by 2023, which will be ready to run in data centers, available on the cloud in early 2022, and in HPC centers (Germany + France) starting in 2023 deployed internally, running hundreds, or even up to thousands of quantum bits."
This successful expansion of the team's neutral atom array to 300+ is certainly a major milestone for Pasqal. According to Pasqal's technology roadmap, the company is on track to achieve 1,000 quantum bits by 2023.
Reference links：
[1]https://pasqal.io/2022/09/14/pasqal-unveils-a-new-quantum-processor-architecture-with-a-record-324-atoms/
[2]https://journals.aps.org/pra/abstract/10.1103/PhysRevA.106.022611
[3]https://mp.weixin.qq.com/s/ZGqC4H-4aSvlnz5ZtDX-tw
