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1. Fast and Parallelizable Logical Computation with Homological Product Codes

   https://doi.org/10.1103/PhysRevX.15.021065  

   Xu, Qian; Zhou, Hengyun; Zheng, Guo; Bluvstein, Dolev; Ataides, J_Pablo Bonilla; Lukin, Mikhail D; Jiang, Liang (May 2025, Physical Review X)

   Quantum error correction is necessary to perform large-scale quantum computation but requires extremely large overheads in both space and time. High-rate quantum low-density-parity-check (qLDPC) codes promise a route to reduce qubit numbers, but performing computation while maintaining low space cost has required serialization of operations and extra time costs. In this work, we design fast and parallelizable logical gates for qLDPC codes and demonstrate their utility for key algorithmic subroutines such as the quantum adder. Our gate gadgets utilize transversal logical s between a data qLDPC code and a suitably constructed ancilla code to perform parallel Pauli product measurements (PPMs) on the data logical qubits. For hypergraph product codes, we show that the ancilla can be constructed by simply modifying the base classical codes of the data code, achieving parallel PPMs on a subgrid of the logical qubits with a lower space-time cost than existing schemes for an important class of circuits. Generalizations to 3D and 4D homological product codes further feature fast PPMs in constant depth. While prior work on qLDPC codes has focused on individual logical gates, we initiate the study of fault-tolerant compilation with our expanded set of native qLDPC code operations, constructing algorithmic primitives for preparing $k$-qubit Greenberger-Horne-Zeilinger states and distilling or teleporting $k$magic states with $O\left(1\right)$space overhead in $O\left(1\right)$and $O\left(\sqrt{k}\log k\right)$logical cycles, respectively. We further generalize this to key algorithmic subroutines, demonstrating the efficient implementation of quantum adders using parallel operations. Our constructions are naturally compatible with reconfigurable architectures such as neutral atom arrays, paving the way to large-scale quantum computation with low space and time overheads. Published by the American Physical Society2025 

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2. Measurements of polarization and spin correlation and observation of entanglement in top quark pairs using $\mathrm{lepton}+\text{jets}$ events from proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$

   https://doi.org/10.1103/PhysRevD.110.112016  

   Hayrapetyan, A; Tumasyan, A; Adam, W; Andrejkovic, J W; Benato, L; Bergauer, T; Chatterjee, S; Damanakis, K; Dragicevic, M; Hussain, P S; et al (December 2024, Physical Review D)

   Measurements of the polarization and spin correlation in top quark pairs ( $t\overline{t}$) are presented using events with a single electron or muon and jets in the final state. The measurements are based on proton-proton collision data from the LHC at $\sqrt{s}=13\mathrm{TeV}$collected by the CMS experiment, corresponding to an integrated luminosity of $138{\mathrm{fb}}^{-1}$. All coefficients of the polarization vectors and the spin correlation matrix are extracted simultaneously by performing a binned likelihood fit to the data. The measurement is performed inclusively and in bins of additional observables, such as the mass of the $t\overline{t}$system and the top quark scattering angle in the $t\overline{t}$rest frame. The measured polarization and spin correlation are in agreement with the standard model. From the measured spin correlation, conclusions on the $t\overline{t}$spin entanglement are drawn by applying the Peres-Horodecki criterion. The standard model predicts entangled spins for $t\overline{t}$states at the production threshold and at high masses of the $t\overline{t}$system. Entanglement is observed for the first time in events at high $t\overline{t}$mass, where a large fraction of the $t\overline{t}$decays are spacelike separated, with an expected and observed significance of above 5 standard deviations. © 2024 CERN, for the CMS Collaboration2024CERN 

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3. Combination of Searches for Resonant Higgs Boson Pair Production Using $pp$ Collisions at $\sqrt{s}=13\mathrm{TeV}$ with the ATLAS Detector

   https://doi.org/10.1103/PhysRevLett.132.231801  

   Aad, G; Aakvaag, E; Abbott, B; Abeling, K; Abicht, N J; Abidi, S H; Aboulhorma, A; Abramowicz, H; Abreu, H; Abulaiti, Y; et al (June 2024, Physical Review Letters)

   A combination of searches for a new resonance decaying into a Higgs boson pair is presented, using up to $139{\mathrm{fb}}^{-1}$of $pp$collision data at $\sqrt{s}=13\mathrm{TeV}$recorded with the ATLAS detector at the LHC. The combination includes searches performed in three decay channels: $b\overline{b}b\overline{b}$, $b\overline{b}{\tau }^{+}{\tau }^{-}$, and $b\overline{b}\gamma \gamma$. No excess above the expected Standard Model background is observed and upper limits are set at the 95% confidence level on the production cross section of Higgs boson pairs originating from the decay of a narrow scalar resonance with mass in the range 251 GeV–5 TeV. The observed (expected) limits are in the range 0.96–600 fb (1.2–390 fb). The limits are interpreted in the type-I two-Higgs-doublet model and the minimal supersymmetric standard model, and constrain parameter space not previously excluded by other searches. © 2024 CERN, for the ATLAS Collaboration2024CERN 

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4. $\omega$ Meson from Lattice QCD

   https://doi.org/10.1103/PhysRevLett.133.211906  

   Yan, Haobo; Mai, Maxim; Garofalo, Marco; Meißner, Ulf-G; Liu, Chuan; Liu, Liuming; Urbach, Carsten (November 2024, Physical Review Letters)

   Many excited states in the hadron spectrum have large branching ratios to three-hadron final states. Understanding such particles from first principles QCD requires input from lattice QCD with one-, two-, and three-meson interpolators as well as a reliable three-body formalism relating finite-volume spectra at unphysical pion mass values to the scattering amplitudes at the physical point. In this work, we provide the first-ever calculation of the resonance parameters of the $\omega$meson from lattice QCD, including an update of the formalism through matching to effective field theories. The main result of this pioneering study, the pole position of the $\omega$meson at $\sqrt{s_{\omega }}=\left(778.0\right(11.2)-i3.0(5\left)\right)\mathrm{MeV}$, agrees reasonably well with experiment. In addition we provide an estimate of the $\omega -\rho$mass difference as 29(15) MeV. Published by the American Physical Society2024 

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5. Efficiently Verifiable Quantum Advantage on Near-Term Analog Quantum Simulators

   https://doi.org/10.1103/PRXQuantum.6.010341  

   Liu, Zhenning; Devulapalli, Dhruv; Hangleiter, Dominik; Liu, Yi-Kai; Kollár, Alicia J; Gorshkov, Alexey V; Childs, Andrew M (March 2025, PRX Quantum)

   Existing schemes for demonstrating quantum computational advantage are subject to various practical restrictions, including the hardness of verification and challenges in experimental implementation. Meanwhile, analog quantum simulators have been realized in many experiments to study novel physics. In this work, we propose a quantum advantage protocol based on verification of an analog quantum simulation, in which the verifier need only run an $O\left({\lambda }^2\right)$-time classical computation, and the prover need only prepare $O\left(1\right)$samples of a history state and perform $O\left({\lambda }^2\right)$single-qubit measurements, for a security parameter $\lambda$. We also propose a near-term feasible strategy for honest provers and discuss potential experimental realizations. Published by the American Physical Society2025 

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