We use a real-space slave-rotor theory of the physics of topological Mott insulators, using the Kane-Mele-Hubbard model as an example, and show that a topological gap in the Green function zeros corresponds to a gap in the bulk spinon spectrum and implies a gapless band of edge zeros and a spinon edge mode. We then consider an interface between a topological Mott insulator and a conventional topological insulator showing how the spinon edge mode of the topological Mott insulator combines with the spin part of the conventional electron topological edge state, leaving a non-Fermi liquid edge mode described by a gapless propagating holon and gapped spinon state. Our work demonstrates the physical meaning of Green function zeros and shows that interfaces between conventional and Mott topological insulators are a rich source of new physics.

Distributed quantum computing is a promising computational paradigm for performing computations that are beyond the reach of individual quantum devices. Privacy in distributed quantum computing is critical for maintaining confidentiality and protecting the data in the presence of untrusted computing nodes. In this Letter, we introduce novel blind quantum machine learning protocols based on the quantum bipartite correlator algorithm. Our protocols have reduced communication overhead while preserving the privacy of data from untrusted parties. We introduce robust algorithm-specific privacy-preserving mechanisms with low computational overhead that do not require complex cryptographic techniques. We then validate the effectiveness of the proposed protocols through complexity and privacy analysis. Our findings pave the way for advancements in distributed quantum computing, opening up new possibilities for privacy-aware machine learning applications in the era of quantum technologies.

Large-scale variational quantum algorithms are widely recognized as a potential pathway to achieve practical quantum advantages. However, the presence of quantum noise might suppress and undermine these advantages, which blurs the boundaries of classical simulability. To gain further clarity on this matter, we present a novel polynomial-scale method based on the path integral of observable’s backpropagation on Pauli paths (OBPPP). This method efficiently approximates expectation values of operators in variational quantum algorithms with bounded truncation error in the presence of single-qubit Pauli noise. Theoretically, we rigorously prove: (i) For a constant minimal nonzero noise rate $\gamma$, OBPPP’s time and space complexity exhibit a polynomial relationship with the number of qubits $n$, the circuit depth $L$. (ii) For variable $\gamma$, in scenarios where more than two nonzero noise factors exist, the complexity remains $\text{Poly}(n,L)$ if $\gamma$ exceeds $1/\log L$, but grows exponential with $L$ when $\gamma$ falls below $1/L$. Numerically, we conduct classical simulations of IBM’s zero-noise extrapolated experimental results on the 127-qubit Eagle processor [Y. Kim et al., Evidence for the utility of quantum computing before fault tolerance, Nature (London) 618, 500 (2023).]. Our method attains higher accuracy and faster runtime compared to the quantum device. Furthermore, our approach allows us to simulate noisy outcomes, enabling accurate reproduction of IBM’s unmitigated results that directly correspond to raw experimental observations. Our research reveals the vital role of noise in classical simulations and the derived method is general in computing the expected value for a broad class of quantum circuits and can be applied in the verification of quantum computers.

Coherent dynamics of interacting quantum particles plays a central role in the study of strongly correlated quantum matter and the pursuit of quantum information processors. Here, we present the state space of interacting Rydberg atoms as a synthetic landscape on which to control and observe coherent and correlated dynamics. With full control of the coupling strengths and energy offsets between the pairs of sites in a nine-site synthetic lattice, we realize quantum walks, Bloch oscillations, and dynamics in an Escher-type “continuous staircase.” In the interacting regime, we observe correlated quantum walks, Bloch oscillations, and confinement of particle pairs. Additionally, we simultaneously tilt our lattice both up and down to achieve coherent pair oscillations. When combined with a few straightforward upgrades, this work establishes synthetic Rydberg lattices of interacting atom arrays as a promising platform for programmable quantum many-body dynamics with access to features that are difficult to realize in real-space lattices.

By means of numerical simulations, we demonstrate the innovative use of computational ghost imaging in transmission electron microscopy to retrieve images with a resolution that overcomes the limitations imposed by coherent aberrations. The method requires measuring the intensity on a single pixel detector with a series of structured illuminations. The success of the technique is improved if the probes are made to resemble the sample and the patterns cover the area of interest evenly. By using a simple 8 electrode device as a specific example, a twofold increase in resolution beyond the aberration limit is demonstrated to be possible under realistic experimental conditions.

The onset and development of electron-positron cascade in a standing wave formed by multiple colliding laser pulses requires tight focusing in order to achieve the maximum laser intensity. There, steep spatiotemporal gradients in the laser intensity expel seed particles from the high-intensity region and thus can prevent the onset of a cascade. We show that radially polarized laser pulses ensure that the seed electrons are present at the focal plane at the moment of the highest amplitude even in the case of extreme focusing. This feature reduces the required laser power for the onset of a cascade 100 times (80 times) compared to circularly (linearly) polarized laser pulses having the same focal spot radius and duration.

Submonolayer amounts of chloroaluminum-phthalocyanine on Cu(100) were studied with scanning tunneling spectroscopy. The molecule can be prepared in a fourfold symmetric state whose conductance spectrum exhibits a zero-bias feature similar to a Kondo resonance. In magnetic fields, however, this resonance splits far more than expected from the spin of a single electron. Density functional theory calculations reveal a charge transfer of 1.3 electrons to the degenerate lowest unoccupied molecular orbitals. These orbitals are mixed by the orbital momentum operator ${\widehat{L}}_z$ with a large matrix element corresponding to $m_L\approx 2.7$. Dehydrogenation of a ligand lifts the degerenracy of the lowest unoccupied molecular orbital, reduces the splitting in magnetic fields, and induces a polarity dependence of the spectra. Using model calculations of the spin, orbital, and vibrational degrees of freedom we show that a dynamical Jahn-Teller effect reproduces the main experimental observations.

Chiral bulk Landau levels and surface arcs, as the two distinctive features unique to Weyl semimetals, have each attracted enormous interest. Recent works have revealed that surface-arc modes can support one-sided chiral hinge modes, a hallmark of the three-dimensional quantum Hall effect, as a combined result of chiral Landau levels of bulk states and magnetic response of surface arcs. Here, we exploit a two-dimensional phononic crystal to construct an ideal Weyl semimetal under a pseudomagnetic field, in which a structural parameter is combined to construct a synthetic three-dimensional space. By directly measuring the acoustic pressure fields, we have not only visualized the one-sided chiral hinge modes, but also observed the quantized Landau level modes. The results pave the way to explore the high-dimensional quantum Hall physics in low-dimensional phononic platforms.

Quantum many-body systems undergoing phase transitions have been proposed as probes enabling beyond-classical enhancement of sensing precision. However, this enhancement is usually limited to a very narrow region around the critical point. Here, we systematically develop a modular approach for introducing multiple phase transitions in a many-body system. This naturally allows us to enlarge the region of quantum-enhanced precision by encompassing the newly created phase boundaries. Our approach is general and can be applied to both symmetry-breaking and topological quantum sensors. In symmetry-breaking sensors, we show that the newly created critical points inherit the original universality class and a simple total magnetization measurement already suffices to locate them. In topological sensors, our modular construction creates multiple bands which leads to a rich phase diagram. In both cases, Heisenberg scaling for Hamiltonian parameter estimation is achieved at all the phase boundaries. This can be exploited to create a global sensor which significantly outperforms a uniform probe.

Gate set tomography (GST) characterizes the process matrix of quantum logic gates, along with measurement and state preparation errors in quantum processors. GST typically requires extensive data collection and significant computational resources for model estimation. We propose a more efficient GST approach for qudits, utilizing the qudit Hadamard and virtual $Z$ gates to construct fiducials while assuming virtual $Z$ gates are error-free. Our method reduces the computational costs of estimating characterization results, making GST more practical at scale. We experimentally demonstrate the applicability of this approach on a superconducting transmon qutrit.

The duration of the neutrino burst from the supernova event SN 1987A is known to be sensitive to exotic sources of cooling, such as axions radiated from the dense and hot hadronic matter thought to constitute the inner core of the supernova. We perform the first quantitative study of the role of hadronic matter beyond the first generation—–in particular strange matter. We do so by consistently including the full baryon and meson octets, and computing axion emissivity induced from baryon-meson to baryon-axion scatterings as well as from baryon decays. We consider a range of supernova thermodynamic conditions, as well as equation-of-state models with different strangeness content. We obtain the first bound on the axial axion-strange-strange coupling, as well as the strongest existing bound on the axion-down-strange counterpart. Our bound on the latter coupling can be as small as $O({10}^{-2})$ for $f_a={10}^9\mathrm{GeV}$.

We introduce a new output amplifier for fully depleted thick $p$-channel CCDs based on double-gate MOSFETs. The charge amplifier is an $n$-type MOSFET specifically designed and operated to couple the fully depleted CCD with high charge-transfer efficiency. The junction coupling between the CCD and MOSFET channels has enabled high sensitivity, demonstrating readout noise of $0.74e_{\mathrm{rms}}^{-}/\mathrm{pix}$ in one pixel charge measurement. We have also demonstrated the nondestructive readout capability of the device. Single-electron and single-photon per pixel counting in the entire CCD pixel array has been made possible through the averaging of ten samples, achieving $0.15e_{\mathrm{rms}}^{-}/\mathrm{pix}$ in a pixel readout time of 2.74 ms. We have demonstrated fully depleted CCD readout with better performance than the floating diffusion and floating gate amplifiers available today, in both single and multisampling regimes, boasting at least 6 times the speed of floating gate amplifiers.

The cellular structure is considered to be a key as a criterion in initiation, propagation, and quenching of terrestrial detonation. While a few studies on type Ia supernovae, which are known to involve detonation, have addressed the importance of the cellular structure, further detailed treatment will benefit enhanced understanding of the explosion outcomes. In the present study, we bridge this gap in the astrophysics and engineering fields, focusing on the detonation in a helium-rich white dwarf envelope as the triggering process for the so-called double-detonation model. The cellular structures are quantified via high-resolution two-dimensional simulations. We demonstrate that widely accepted terrestrial-experimental criteria for quenching and initiation of detonation can indeed explain the results of previous hydrodynamic simulations very well. The present study highlights the potential of continuing to apply the insight from terrestrial detonation experiments to astrophysical problems, specifically the long unresolved problem of the explosion mechanism of type Ia supernovae.

We study the formation of primordial black holes (PBHs) with ultraslow-roll inflation when stochastic effects are important. We use the $\mathrm{\Delta }N$ formalism and simplify the stochastic equations with an analytical constant-roll approximation. Considering a viable inflation model, we find the spatial profile of the PBH compaction function numerically for each stochastic patch, without assumptions about Gaussianity or the radial profile. The stochastic effects that lead to an exponential tail for the density distribution also make the compaction function very spiky, unlike as assumed in the literature. Naively using collapse thresholds found for smooth profiles, the PBH abundance is enhanced by up to a factor of ${10}^9$, and the PBH mass distribution is spread over 3 orders of magnitude in mass. The results point to a need to redo numerical simulations of PBH formation with spiky profiles.

Using $7.33{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ collision data collected by the BESIII detector at center-of-mass energies in the range of $\sqrt{s}=4.128–4.226\mathrm{GeV}$, we search for the rare decays $D_s^{+}\to h^{+}(h^0)e^{+}{e}^{-}$, where $h$ represents a kaon or pion. By requiring the $e^{+}{e}^{-}$ invariant mass to be consistent with a $\varphi (1020)$, $0.98<M(e^{+}{e}^{-})<1.04\mathrm{GeV}/c^2$, the decay $D_s^{+}\to {\pi }^{+}\varphi$, $\varphi \to e^{+}{e}^{-}$ is observed with a statistical significance of $7.8\sigma$, and evidence for the decay $D_s^{+}\to {\rho }^{+}\varphi$, $\varphi \to e^{+}{e}^{-}$ is found for the first time with a statistical significance of $4.4\sigma$. The decay branching fractions are measured to be $\mathcal{B}(D_s^{+}\to {\pi }^{+}\varphi ,\varphi \to e^{+}{e}^{-})=(1.17_{-0.21}^{+0.23}\pm 0.03)\times {10}^{-5}$, and $\mathcal{B}(D_s^{+}\to {\rho }^{+}\varphi ,\varphi \to e^{+}{e}^{-})=(2.44_{-0.62}^{+0.67}\pm 0.16)\times {10}^{-5}$, where the first uncertainties are statistical and the second systematic. No significant signals for the three four-body decays of $D_s^{+}\to {\pi }^{+}{\pi }^0{e}^{+}{e}^{-}$, $D_s^{+}\to K^{+}{\pi }^0{e}^{+}{e}^{-}$, and $D_s^{+}\to K_S^0{\pi }^{+}{e}^{+}{e}^{-}$ are observed. For $D_s^{+}\to {\pi }^{+}{\pi }^0{e}^{+}{e}^{-}$, the $\varphi$ mass region is vetoed to minimize the long-distance effects. The 90% confidence level upper limits set on the branching fractions of these decays are in the range of $(7.0–8.1)\times {10}^{-5}$.

The origin of neutrino masses remains unknown. Both the vacuum mass and the dark mass generated by the neutrino interaction with dark matter (DM) particles or fields can fit the current oscillation data. The dark mass squared is proportional to the DM number density and, therefore, varies on the galactic scale with much larger values around the Galactic Center. This affects the group velocity and the arrival time delay of core-collapse supernovae (SN) neutrinos. This time delay, especially for the ${\nu }_e$ neutronization peak with a sharp time structure, can be used to distinguish the vacuum and dark neutrino masses. For illustration, we explore the potential of the Deep Underground Neutrino Experiment (DUNE), which is sensitive to ${\nu }_e$. Our simulations show that DUNE can distinguish the two neutrino mass origins at more than $5\sigma$ C.L., depending on the observed local value of neutrino mass, the neutrino mass ordering, the DM density profile, and the SN location.

High-resolution measurements of the positronium formation cross sections for positron energies from threshold to 10 eV are presented for aniline (${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{NH}}_2$), pyridine (${\mathrm{C}}_5{\mathrm{H}}_5\mathrm{N}$), and cyclopentane (${\mathrm{C}}_5{\mathrm{H}}_{10}$). The data reveal that the measured energy dependence of the cross sections on the excess energy in the near-threshold region (1–2 eV) is nearly identical to that of the corresponding photoionization cross sections. This similarity occurs despite the difference between the basic threshold laws for processes without and with a Coulomb interaction between the final-state particles. It is proposed here that the near-threshold behavior of these two different ionization processes is governed by the vibrational dynamics of the final-state cation. This is supported by comparison of the data with the calculated spectrum of vibronic intensities for the pyridine cation [Trofimov et al., J. Chem. Phys. 153, 164307 (2020)].

Two-photon double ionization is a paradigmatic example of how electron correlation manifests. In molecular targets, its coupling with the slower nuclear motion introduces an additional complication and induces electron-electron-nuclei correlations. Experimentally, momentum-coincident measurements can provide a complete kinematical image of the molecular full Coulomb breakup. Previous theoretical studies have described this process by ignoring nuclear motion and the subsequent Coulomb explosion of the dication. Here we show, by means of a full-dimensional treatment of two-photon double ionization of the ${\mathrm{H}}_2$ molecule, that nuclear motion plays a decisive role even for pulses as short as 1.5 fs, a time during which the nuclei are not expected to move significantly. We find strong correlations between nuclear and electronic degrees of freedom, giving access to different electronic processes as a function of nuclear kinetic energy. In particular, we observe unexpectedly strong back-to-back asymmetry in the photoelectron angular distributions, as well as novel interferences resulting from the coherent contributions from two-photon sequential absorption paths via different molecular cationic states.