Reducing circuit depth and identifying an optimal trade-off between circuit depth and width is crucial for successful quantum computation. In this context, midcircuit measurement and feedforward have been shown to significantly reduce the depth of quantum circuits, particularly in implementing logical gates. By leveraging these techniques, we propose several parallelization strategies that reduce quantum circuit depth at the expense of increasing width in preparing various quantum states relevant to quantum simulation. With measurements and feedforward, we demonstrate that utilizing unary encoding as a bridge between two quantum states substantially reduces the circuit depth required for preparing quantum states, such as sparse quantum states and sums of Slater determinants within the first quantization framework, while maintaining an efficient circuit width. Additionally, we show that a Bethe wave function, characterized by its high degree of freedom in its phase, can be probabilistically prepared in a constant-depth quantum circuit using measurements and feedforward. We anticipate that our study will contribute to the reduction of circuit depth in initial state preparation, particularly for quantum simulation, which is a critical step toward achieving quantum advantage.

The learner's ability to generate a hypothesis that closely approximates the target function is crucial in machine learning. Achieving this requires sufficient data; however, unauthorized access by an eavesdropping learner can lead to security risks. Thus, it is important to ensure the performance of the "authorized" learner by limiting the quality of the training data accessible to eavesdroppers. Unlike previous studies focusing on encryption or access controls, we provide a theorem to ensure superior learning outcomes exclusively for the authorized learner with quantum label encoding. In this context, we use the probably-approximately-correct (PAC) learning framework and introduce the concept of learning probability to quantitatively assess learner performance. Our theorem allows the condition that, given a training dataset, an authorized learner is guaranteed to achieve a certain quality of learning outcome, while eavesdroppers are not. Notably, this condition can be constructed based only on the authorized-learning-only measurable quantities of the training data, i.e., its size and noise degree. We validate our theoretical proofs and predictions through convolutional neural networks (CNNs) image classification learning.

The k.p perturbation method for determination of electronic structure first pioneered by Kohn and Luttinger continues to provide valuable insight to several band structure features. This method has been adopted to heterostructures confined up to three directions. In this paper, numerical details of setting up a k.p Hamiltonian using the finite difference approximation for such confined nanostructures is explicitly demonstrated. Nanostructures belonging to two symmetry classes namely cubic zincblende and rhombohedral crystals are considered. Rhombohedral crystals, of late, have gained prominence as candidates for the recently discovered topological insulator (TI) class of materials. Lastly the incorporation of strain field to the k.p Hamiltonian and matrix equations for computing the intrinsic and externally applied strain in heterostructures within a continuum approximation is shown. Two applications are considered 1)Computation of the eigen states of a multi-million zincblende InAs quantum dot with a stress-reducing InGaAs layer of varying Indium composition embedded in a GaAs matrix and 2)Dispersion of a rhombohedral topological insulator Bi$_{2}$Se$_{3}$ film.

The angular distribution of gravitational-wave power from persistent sources may exhibit anisotropies arising from the large-scale structure of the Universe. This motivates directional searches for astrophysical and cosmological gravitational-wave backgrounds, as well as continuous-wave emitters. We present results of such a search using data from the first observing run through the first portion of the fourth observing run of the LIGO-Virgo-KAGRA Collaborations. We apply gravitational-wave radiometer techniques to generate skymaps and search for both narrowband and broadband persistent gravitational-wave sources. Additionally, we use spherical harmonic decomposition to probe spatially extended sources. No evidence of persistent gravitational-wave signals is found, and we set the most stringent constraints to date on such emissions. For narrowband point sources, our sensitivity estimate to effective strain amplitude lies in the range $(0.03 - 8.4) \times 10^{-24}$ across all sky and frequency range $(20 - 160)$ Hz. For targeted sources -- Scorpius X-1, SN 1987A, the Galactic Center, Terzan 5, and NGC 6397 -- we constrain the strain amplitude with best limits ranging from $\sim 1.1 \times 10^{-25}$ to $6.5 \times 10^{-24}$. For persistent broadband sources, we constrain the gravitational-wave flux F_{\alpha, \hat{n}}^{95\%, \mathrm{UL}}(25\, \mathrm{Hz}) < (0.008 - 5.5) \times 10^{-8}\, \mathrm{erg\, cm^{-2}\, s^{-1}\, Hz^{-1}}, depending on the sky direction $\hat{n}$ and spectral index $\alpha=0,\,2/3,\,3$. Finally, for extended sources, we place upper limits on the strain angular power spectrum C_\ell^{1/2} < (0.63 - 17) \times 10^{-10} \,\mathrm{sr}^{-1}.

We report a measurement of the cross section for the process $e^+e^-\to\pi^+\pi^-J/\psi$ around the $X(3872)$ mass in search for the direct formation of $e^+e^-\to X(3872)$ through the two-photon fusion process. No enhancement of the cross section is observed at the $X(3872)$ peak and an upper limit on the product of electronic width and branching fraction of $X(3872)\to\pi^+\pi^-J/\psi$ is determined to be \Gamma_{ee}\times\mathcal{B}(X(3872)\to\pi^+\pi^-J/\psi)<7.5\times10^{-3}\,\text{eV} at $90\,\%$ confidence level under an assumption of total width of $1.19\pm0.21$ MeV. This is an improvement of a factor of about $17$ compared to the previous limit. Furthermore, using the latest result of $\mathcal{B}(X(3872)\to\pi^+\pi^-J/\psi)$, an upper limit on the electronic width $\Gamma_{ee}$ of $X(3872)$ is obtained to be <0.32\,\text{eV} at the $90\,\%$ confidence level.

The dark photon, $A^\prime$, and the dark Higgs boson, $h^\prime$, are hypothetical constituents featured in a number of recently proposed Dark Sector Models. Assuming prompt decays of both dark particles, we search for their production in the so-called Higgs-strahlung channel, $e^+e^- \rightarrow A^\prime h'$, with $h^\prime \rightarrow A^\prime A^\prime$. We investigate ten exclusive final-states with $A^\prime \rightarrow e^+e^-$, $\mu^+\mu^-$, or $\pi^+\pi^-$, in the mass ranges $0.1$~GeV/$c^2$~< m_{A^\prime} < 3.5~GeV/$c^2$ and $0.2$~GeV/$c^2$~< m_{h'} < 10.5~GeV/$c^2$. We also investigate three inclusive final-states, $2(e^+e^-)X$, $2(\mu^+\mu^-)X$, and $(e^+e^-)(\mu^+\mu^-)X$, where $X$ denotes a dark photon candidate detected via missing mass, in the mass ranges $1.1$~GeV/$c^2$~< m_{A^\prime} < 3.5~GeV/$c^2$ and $2.2$~GeV/$c^2$~< m_{h'} < 10.5~GeV/$c^2$. Using the entire $977\,\mathrm{fb}^{-1}$ data set collected by Belle, we observe no significant signal. We obtain individual and combined 90$\%$ confidence level upper limits on the branching fraction times the Born cross section, $\cal B \times \sigma_{\mathrm{Born}}$, on the Born cross section, $\sigma_{\mathrm{Born}}$, and on the dark photon coupling to the dark Higgs boson times the kinetic mixing between the Standard Model photon and the dark photon, $\alpha_D \times \epsilon^2$. These limits improve upon and cover wider mass ranges than previous experiments. The limits from the final-states $3(\pi^+\pi^-)$ and $2(e^+e^-)X$ are the first placed by any experiment. For $\alpha_D$ equal to 1/137, m_{h'}< 8 GeV/$c^2$, and m_{A^\prime}< 1 GeV/$c^2$, we exclude values of the mixing parameter, $\epsilon$, above $\sim 8 \times 10^{-4}$.

We present results of renormalization factors for bilinear operators obtained using the nonperturbative renormalization method (NPR) in the RI-SMOM schemes. The operators are constructed using HYP staggered quarks on the MILC asqtad lattice ($N_f=2+1$). We compare results in the RI-SMOM schemes with those in the RI-MOM scheme for the $V\otimes S$ and $S\otimes S$ operators. Since we use Landau gauge fixing, we study the effect of Gribov ambiguity on the wave function renormalization $Z_q$ in the RI-MOM scheme. We find that the Gribov uncertainty is negligibly small for $Z_q$ in the RI-MOM scheme.

We search for $CP$ violation in the charged charm meson decay $D^{+}\to\pi^{+}\pi^{0}$, based on a data sample corresponding to an integrated luminosity of $\rm 921~fb^{-1}$ collected by the Belle experiment at the KEKB $e^{+}e^{-}$ asymmetric-energy collider. The measured $CP$ violating asymmetry is $[+2.31\pm1.24({\rm stat})\pm0.23({\rm syst})]\%$, which is consistent with the standard model prediction and has a significantly improved precision compared to previous results.

We employ the operational quasiprobability (OQ) as a work distribution, which reproduces the Jarzynski equality and yields the average work consistent with the classical definition. The OQ distribution can be experimentally implemented through the end-point measurement and the two-point measurement scheme. Using this framework, we demonstrate the explicit contribution of coherence to the fluctuation, the average, and the second moment of work. In a two-level system, we show that non-joint measurability, a generalized notion of measurement incompatibility, can increase the amount of extractable work beyond the classical bound imposed by jointly measurable measurements. We further prove that the real part of Kirkwood-Dirac quasiprobability (KDQ) and the OQ are equivalent in two-level systems, and they are nonnegative for binary unbiased measurements if and only if the measurements are jointly measurable. In a three-level Nitrogen-vacancy center system, the OQ and the KDQ exhibit different amounts of negativities while enabling the same work extraction, implying that the magnitude of negativity is not a faithful indicator of nonclassical work. These results highlight that coherence and non-joint measurability play fundamental roles in the enhancement of work.

We present measurements of B+ -> Dbar*0 tau+ nu_tau and B+ -> Dbar^0 tau+ nu_tau decays in a data sample of 657 x 10^6 BBbar pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. We find 446^{+58}_{-56} events of the decay B+ -> Dbar*0 tau+ nu_tau with a significance of 8.1 standard deviations, and 146^{+42}_{-41} events of the decay B+ -> Dbar0 tau+ nu_tau with a significance of 3.5 standard deviations. The latter signal provides the first evidence for this decay mode. The measured branching fractions are B(B+ -> Dbar*0 tau+ nu_tau)=(2.12^{+0.28}_{-0.27} (stat) +- 0.29 (syst)) % and B(B+ -> Dbar0 tau+ nu_tau)=(0.77 +- 0.22 (stat) +- 0.12 (syst)) %.

Understanding how fluctuations arise and spread in the international trade system can help assess the current state and guide future developments. We analyze the world trade data to investigate strong adverse fluctuations, characterized here as `collapsed trades' -- individual trades that experience significant declines in annual trade volume compared to the previous year. Adopting a hypergraph framework for a fine-scale trade-centric representation of international trade, we find that collapsed trades are clustered similar to infectious disease outbreaks in societies. Moreover, the portion of collapsed trades is found to be negatively correlated with trade volume. We develop a collapse propagation model, an epidemic-like model with a weight-dependent infection rate, that reproduces all the essential empirical features. Through both analytical and numerical analysis, we identify two key factors that synergistically suppress the onset of global collective collapse and serve as a joint stabilizing mechanism for the international economy: i) a positive correlation between a trade's degree (the number of adjacent trades) and its volume and ii) an algebraically decaying infection rate with trade volume. In particular, the second factor weakened during the 2008--2009 global economic recession, possibly explaining the broader spread of collapse.

Quantum circuit simulations play a critical role in bridging the gap between theoretical quantum algorithms and their practical realization on physical quantum hardware, yet they face computational challenges due to the exponential growth of quantum state spaces with increasing qubit size. This work presents PennyLane-Lightning MPI, an MPI-based extension of the PennyLane-Lightning suite, developed to enable scalable quantum circuit simulations through parallelization of quantum state vectors and gate operations across distributed-memory systems. The core of this implementation is an index-dependent, gate-specific parallelization strategy, which fully exploits the characteristic of individual gates as well as the locality of computation associated with qubit indices in partitioned state vectors. Benchmarking tests with single gates and well-designed quantum circuits show that the present method offers advantages in performance over general methods based on unitary matrix operations and exhibits excellent scalability, supporting simulations of up to 41-qubit with hundreds of thousands of parallel processes. Being equipped with a Python plug-in for seamless integration to the PennyLane framework, this work contributes to extending the PennyLane ecosystem by enabling high-performance quantum simulations in standard multi-core CPU clusters with no library-specific requirements, providing a back-end resource for the cloud-based service framework of quantum computing that is under development in the Republic of Korea.

We report new measurements of the total cross sections for $e^+e^-\to \Upsilon(n{\rm S})\pi^+\pi^-$ ($n$ = 1, 2, 3) and $e^+e^-\to b\bar b$ from a high-luminosity fine scan of the region $\sqrt{s} = 10.63$-$11.05$ GeV with the Belle detector. We observe that the $\Upsilon(n{\rm S})\pi^+\pi^-$ spectra have little or no non-resonant component and extract from them the masses and widths of $\Upsilon(10860)$ and $\Upsilon(11020)$ and their relative phase. We find $M_{10860}=(10891.1\pm3.2^{+0.6}_{-1.7})$ MeV/$c^2$ and $\Gamma_{10860}=(53.7^{+7.1}_{-5.6}\,^{+1.3}_{-5.4})$ MeV and report first measurements $M_{11020}=(10987.5^{+6.4}_{-2.5}\,^{+9.0}_{-2.1})$ MeV/$c^2$, $\Gamma_{11020}=(61^{+9}_{-19}\,^{+2}_{-20})$ MeV, and $\phi_{\rm 11020}-\phi_{\rm 10860} = (-1.0\pm0.4\,^{+1.4}_{-0.1})$ rad.

We search for lepton-flavor-violating tau-> ell V^0 decays, where ell is an electron or muon and V^0 is one of the vector mesons rho^0, phi, omega, K*0 and K*0-bar. We use 854 fb^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. No evidence for a signal is found in any decay mode, and we obtain 90% confidence level upper limits on the individual branching fractions in the range (1.2-8.4)*10^{-8}.

In classical information theory, uncommon information refers to the amount of information that is not shared between two messages, and it admits an operational interpretation as the minimum communication cost required to exchange the messages. Extending this notion to the quantum setting, quantum uncommon information is defined as the amount of quantum information necessary to exchange two quantum states. While the value of uncommon information can be computed exactly in the classical case, no direct method is currently known for calculating its quantum analogue. Prior work has primarily focused on deriving upper and lower bounds for quantum uncommon information. In this work, we propose a new approach for estimating these bounds by utilizing the quantum Donsker-Varadhan representation and implementing a gradient-based optimization method. Our results suggest a pathway toward efficient approximation of quantum uncommon information using variational techniques grounded in quantum neural architectures.

We present an efficient and accurate algorithm for solving the Poisson equation in spherical polar coordinates with a logarithmic radial grid and open boundary conditions. The method employs a divide-and-conquer strategy, decomposing the computational domain into hierarchical units with varying cell sizes. James's algorithm is used to compute the zero-boundary potentials of lower-level units, which are systematically integrated to reconstruct the zero-boundary potential over the entire domain. These calculations are performed efficiently via matrix-vector operations using various precomputed kernel matrices. The open-boundary potential is then obtained by applying a discrete Green's function to the effective screening density induced at the domain boundaries. The overall algorithm achieves a computational complexity of $\mathcal{O}(N^3 \log N)$, where $N$ denotes the number of cells in one dimension. We implement the solver in the FARGO3D magnetohydrodynamics code and demonstrate its performance and second-order accuracy through a series of test problems.

We search for gravitational-wave signals associated with gamma-ray bursts detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (1 November 2019 15:00 UTC-27 March 2020 17:00 UTC).We conduct two independent searches: a generic gravitational-wave transients search to analyze 86 gamma-ray bursts and an analysis to target binary mergers with at least one neutron star as short gamma-ray burst progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these gamma-ray bursts. A weighted binomial test of the combined results finds no evidence for sub-threshold gravitational wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each gamma-ray burst. Finally, we constrain the population of low luminosity short gamma-ray bursts using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate.

The cross sections of the processes $e^+ e^- \to K^+ K^- J/\psi$ and $K_S^0K_S^0J/\psi$ are measured via initial state radiation at center-of-mass energies between the threshold and 6.0~GeV using a data sample of 980~fb$^{-1}$ collected with the Belle detector on or near the $\Upsilon(nS)$ resonances, where $n=$1, 2, ..., 5. The cross sections for $e^+ e^- \to K^+ K^- J/\psi$ are at a few pb level and the average cross section for $e^+ e^- \to K_S^0K_S^0J/\psi$ is $1.8\pm 0.6 (\rm stat.)\pm 0.3 (\rm syst.)$~pb between 4.4 and 5.2~GeV. All of them are consistent with previously published results with improved precision. A search for resonant structures and associated intermediate states in the cross section of the process $e^+ e^- \to K^+ K^- J/\psi$ is performed.

We report measurements of branching fractions of $\tau$ lepton decays to final states with a $K^{0}_{S}$ meson using a 669 fb$^{-1}$ data sample accumulated with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. The inclusive branching fraction is measured to be $\mathcal{B}(\tau^{-} \to K^{0}_{S}\ X^{-} \nu_{\tau})=(9.15 \pm 0.01 \pm 0.15) \times 10^{-3}$, where $X^{-}$ can be anything; the exclusive branching fractions are $\mathcal{B}(\tau^{-} \to \pi^{-} K^{0}_{S} \nu_{\tau}) = (4.16 \pm 0.01 \pm 0.08) \times 10^{-3}$, $\mathcal{B}(\tau^{-} \to K^{-} K^{0}_{S} \nu_{\tau}) = (7.40 \pm 0.07 \pm 0.27) \times 10^{-4}$, $\mathcal{B}(\tau^{-} \to \pi^{-} K^{0}_{S} \pi^{0} \nu_{\tau}) = (1.93 \pm 0.02 \pm 0.07) \times 10^{-3}$, $\mathcal{B}(\tau^{-} \to K^{-} K^{0}_{S} \pi^{0} \nu_{\tau}) = (7.48 \pm 0.10 \pm 0.37)\times 10^{-4}$, $\mathcal{B}(\tau^{-} \to \pi^{-} K^{0}_{S} K^{0}_{S} \nu_{\tau}) = (2.33 \pm 0.03 \pm 0.09) \times 10^{-4}$, $\mathcal{B}(\tau^{-} \to \pi^{-} K^{0}_{S} K^{0}_{S} \pi^{0} \nu_{\tau}) = (2.00 \pm 0.22 \pm 0.20) \times 10^{-5}$, where the first uncertainty is statistical and the second is systematic. For each mode, the accuracy is improved over that of pre-$B$-factory measurements by a factor ranging from five to ten. In $\tau^{-} \to \pi^{-} K^0_S K^0_S \pi^{0} \nu_{\tau}$ decays, clear signals for the intermediate states $\tau^{-} \to \pi^- f_{1}(1285)\nu_{\tau}$ and $\tau^{-} \to K^{*-}K^{0}_{S} \pi^{0} \nu_{\tau}$ are observed.

We perform \textit{ab initio} nuclear lattice calculations of the neutron-rich carbon and oxygen isotopes using high-fidelity chiral interactions. We find good agreement with the observed binding energies and compute correlations associated with each two-nucleon interaction channel. For the isospin $T=1$ channels, we show that the dependence on $T_z$ provides a measure of the correlations among the extra neutrons in the neutron-rich nuclei. For the spin-singlet S-wave channel, we observe that any paired neutron interacts with the nuclear core as well as its neutron pair partner, while any unpaired neutron interacts primarily with only the nuclear core. For the other partial waves, the correlations among the extra neutrons grow more slowly and smoothly with the number of neutrons. These general patterns are observed in both the carbon and oxygen isotopes and may be universal features that appear in many neutron-rich nuclei.