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  1. Realizing quantum speedup for practically relevant, computationally hard problems is a central challenge in quantum information science. Using Rydberg atom arrays with up to 289 qubits in two spatial dimensions, we experimentally investigate quantum algorithms for solving the Maximum Independent Set problem. We use a hardware-efficient encoding associated with Rydberg blockade, realize closed-loop optimization to test several variational algorithms, and subsequently apply them to systematically explore a class of graphs with programmable connectivity. We find the problem hardness is controlled by the solution degeneracy and number of local minima, and experimentally benchmark the quantum algorithm’s performance against classical simulated annealing.more »On the hardest graphs, we observe a superlinear quantum speedup in finding exact solutions in the deep circuit regime and analyze its origins.« less
    Free, publicly-accessible full text available May 5, 2023
  2. Free, publicly-accessible full text available August 1, 2022
  3. Bartoli, A ; Fusiello, A (Ed.)
    We propose an improved discriminative model prediction method for robust long-term tracking based on a pre-trained short-term tracker. The baseline pre-trained short-term tracker is SuperDiMP which combines the bounding-box regressor of PrDiMP with the standard DiMP classifier. Our tracker RLT-DiMP improves SuperDiMP in the follow- ing three aspects: (1) Uncertainty reduction using random erasing: To make our model robust, we exploit an agreement from multiple im- ages after erasing random small rectangular areas as a certainty. And then, we correct the tracking state of our model accordingly. (2) Ran- dom search with spatio-temporal constraints: we propose a robust ran- dommore »search method with a score penalty applied to prevent the prob- lem of sudden detection at a distance. (3) Background augmentation for more discriminative feature learning: We augment various backgrounds that are not included in the search area to train a more robust model in the background clutter. In experiments on the VOT-LT2020 bench- mark dataset, the proposed method achieves comparable performance to the state-of-the-art long-term trackers. The source code is available at: https://github.com/bismex/RLT-DIMP.« less
  4. Free, publicly-accessible full text available August 1, 2022
  5. Free, publicly-accessible full text available July 1, 2022
  6. Abstract The interconversion of charge and spin currents via spin-Hall effect is essential for spintronics. Energy-efficient and deterministic switching of magnetization can be achieved when spin polarizations of these spin currents are collinear with the magnetization. However, symmetry conditions generally restrict spin polarizations to be orthogonal to both the charge and spin flows. Spin polarizations can deviate from such direction in nonmagnetic materials only when the crystalline symmetry is reduced. Here, we show control of the spin polarization direction by using a non-collinear antiferromagnet Mn 3 GaN, in which the triangular spin structure creates a low magnetic symmetry while maintainingmore »a high crystalline symmetry. We demonstrate that epitaxial Mn 3 GaN/permalloy heterostructures can generate unconventional spin-orbit torques at room temperature corresponding to out-of-plane and Dresselhaus-like spin polarizations which are forbidden in any sample with two-fold rotational symmetry. Our results demonstrate an approach based on spin-structure design for controlling spin-orbit torque, enabling high-efficient antiferromagnetic spintronics.« less
  7. Abstract

    We report the identification of metastable isomeric states of$$^{228}$$228Ac at 6.28 keV, 6.67 keV and 20.19 keV, with lifetimes of an order of 100 ns. These states are produced by the$$\beta $$β-decay of$$^{228}$$228Ra, a component of the$$^{232}$$232Th decay chain, with$$\beta $$βQ-values of 39.52 keV, 39.13 keV and 25.61 keV, respectively. Due to the low Q-value of$$^{228}$$228Ra as well as the relative abundance of$$^{232}$$232Th and their progeny in low background experiments, these observations potentially impact the low-energy background modeling of dark matter search experiments.

  8. We report a simple approach to develop transient microbial fuel cells with the capability of dissolving in water after stable power generation within a programmed period. This novel watersoluble biobattery makes use of the integration of a dissolvable paper-based substrate, a simple pencil-drawn graphite anode, and a Prussian-blue (PB) cathode. The device features (i) a low cost transient paper-based platform, (ii) easily accessible electrode materials and simple fabrication steps and (iii) a time-controlled operation by using the number of serpentine microfluidic channels. The biobatteries reached to a maximum power of 0.5μW and a current 15.6μA