Stabilizer states, along with Clifford manipulations (unitary transformations and measurements) thereof—despite being efficiently simulable on a classical computer—are an important tool in quantum information processing, with applications to quantum computing, error correction, and networking. Graph states, defined on a graph, are a special class of stabilizer states that are central to measurement-based quantum computing, all-photonic quantum repeaters, distributed quantum computing, and entanglement distribution in a network. All stabilizer states are local-Clifford equivalent to graph states. In this article, we review the stabilizer framework and extend it by incorporating general stabilizer measurements such as multiqubit joint projections. We provide an explicit procedure—using Karnaugh maps from Boolean algebra—for converting arbitrary stabilizer gates into tableau operations of the <sc>cnot</sc>–Hadamard–Phase formalism for efficient stabilizer manipulations. We derive graphical rules for arbitrary stabilizer manipulations of graph states, including multiqubit stabilizer projections and unitaries. We implement the graphical rulebook resulting from above into a MATLAB simulator with a graphical user interface. A user of this tool, e.g., for research in quantum networks, will not require any background in quantum information or the stabilizer framework.
Atomic physics. Constitution and properties of matter, Materials of engineering and construction. Mechanics of materials
We consider exact quantum circuit synthesis, quantum gate efficiency, and the spectral gap conjecture from the perspective of computable analysis. Circuit synthesis, in both its exact and its approximate variant, is fundamental to the circuit model of quantum computing. As an engineering problem, however, the practical and theoretical aspects of quantum circuit synthesis are far from being fully understood. Particularly, this concerns explicit methods for gate-agnostic circuit synthesis and questions of gate efficiency. More than 20 years ago, Harrow et al. published their famous spectral gap theorem: given a suitable family of quantum gates, it is possible to approximate any unitary transformation by means of a quantum circuit whose length is proportional to the required accuracy’s logarithm. Moreover, Harrow et al. suspected that all universal gate families allow for this type of approximation, a hypothesis that became known as the spectral gap conjecture and remains unproven until today. Being an entirely classical task, quantum circuit synthesis must be considered in the context of digital computing, that is, in the context of Turing computability and computable analysis. Using the relevant mathematical framework, we establish no-go results concerning exact quantum circuit synthesis and quantum big-O analysis. Our findings relate to the theory of approximate t-designs, which has recently received notable attention through the literature. Moreover, as follows from our findings, the existence of an algorithm that computes leading big-O coefficients would prove the spectral gap conjecture true within the computable special unitary group.
Atomic physics. Constitution and properties of matter, Materials of engineering and construction. Mechanics of materials
Ultralight dark matter is a hypothetical class of particle with a number of interesting theoretical and experimental properties, many of which are best understood by direct analogy with or application of undergraduate physics. We present a series of exercises and discussions which may inspire the reader to bring contemporary research on ultralight dark matter into the undergraduate classroom.
Abstract Atomic force microscopy is a powerful tool to measure mechanics of soft materials and cells. Standard methods, like the Hertz model, often yield confusing results because it ignores rough surfaces and the fuzzy pericellular layer surrounding cells. This progress report reviews a better approach, the brush model. This model accounts for the rough, brush-like outer layer of cells and solid surfaces. By separating this surface layer from the main cell body, the model reveals the absolute value of Young’s modulus of the cell body. It also measures the thickness and density of the brush layer itself. We review recent progress with this method, covering its basic theory, lab tests, and error analysis. We also highlight its growing success in detecting cancer and studying diseases. Overall, the brush model provides accurate absolute measurements that improve our understanding of cell mechanics as well as the mechanics of soft materials at the nanoscale.
O. V. Svarychevska, I. O. Pavlenko, I. A. Maliuk
et al.
This paper presents the results of the analysis of data obtained during routine radiation monitoring in the area of the WWR-M research nuclear reactor (RNR) of the Institute for Nuclear Research (INR) of the NAS of Ukraine for 2021-2024. Since the commissioning of the RNR, a systematic analysis of the dynamics of the levels of total β-activity of settling dust and atmospheric precipitation, discharge water from the INR of the NAS of Ukraine collectors, the concentration of β-active aerosols in the surface air layer, and the content of major radionuclides of technogenic origin (primarily 137Cs) in soil and vegetation samples has been carried out. Measurements of the ambient dose equivalent of γ radiation at control points are also being carried out. Long-term studies were carried out in the laboratory of the Center for Ecological Problems of Atomic Energetics (CEPAE) of the INR of the NAS of Ukraine, which allowed to accumulate the significant material for analysis of the radiation situation in the area of RNR disposition. It was shown that there is no man-made radioactive pollution of the environment. Over the years of radiation monitoring, the indicators of radiation pollution of the environment in the sanitary protection zone and the observation zone did not exceed the values of the natural background. It is extremely important that an integral stage of the life cycle of RNR is its decommissioning (DR), during which a set of technical measures is consistently carried out, and aimed at stopping any activity related to the functional appointment of the reactor and its transformation into an environmentally safe facility. In this case, a number of additional radiation monitoring tasks may arise, which purpose is to minimize risks during work with DR.
Atomic physics. Constitution and properties of matter
We bring forward a Green function approach for the prediction of Floquet topological phases in driven superconductor–semiconductor hybrids. Although it is common to treat the superconducting component as a mere Cooper-pair reservoir, it was recently pointed out that such an approximation breaks down in the presence of driving, due to the emergence of level broadening. Here, we go beyond these recent studies and prescribe how to construct the Floquet topological invariants for such driven hybrids. In particular, we propose to first obtain the midgap quasi-energy spectra by including the hermitian part of the semiconductor’s self-energy and, subsequently, read out the respective level broadenings by projecting the anti-hermitian part of the self-energy onto the quasi-energy eigenvectors. We exemplify our approach for a Rashba nanowire coupled to a superconductor and a time-dependent Zeeman field. Using our method, we obtain the Floquet band structure, the respective level broadenings, and the topological invariants. Our analysis reinforces the need to properly account for the self-energy, and corroborates that broadening effects can hinder the observation of the Floquet topological phases and especially of those harboring Majorana π modes.
Atomic physics. Constitution and properties of matter
In recent years, variational quantum algorithms have gained significant attention due to their adaptability and efficiency on near-term quantum hardware. They have shown potential in a variety of tasks, including linear algebra, search problems, Gibbs, and ground state preparation. Nevertheless, the presence of noise in current day quantum hardware severely limits their performance. In this work, we introduce dissipative variational quantum algorithms (D-VQAs) by incorporating dissipative operations, such as qubit RESET and stochastic gates, as an intrinsic part of a variational quantum circuit. We argue that such dissipative variational algorithms possess some natural resilience to dissipative noise. We demonstrate how such algorithms can prepare Gibbs states over a wide range of quantum many-body Hamiltonians and temperatures, while significantly reducing errors due to both coherent and noncoherent noise. An additional advantage of our approach is that no ancilla qubits are need. Our results highlight the potential of D-VQAs to enhance the robustness and accuracy of variational quantum computations on noisy intermediate-scale quantum (NISQ) devices.
Atomic physics. Constitution and properties of matter, Materials of engineering and construction. Mechanics of materials
Diogo Cruz, Francisco A. Monteiro, Andre Roque
et al.
This work addresses the open question of implementing fault-tolerant quantum random linear codes (QRLCs) with feasible computational overhead. We present a new decoder for QRLCs capable of dealing with imperfect decoding operations. A first approach, introduced by Cruz et al. (2023), only considered channel errors and perfect gates at the decoder. Here, we analyze the fault-tolerant characteristics of QRLCs with a new noise guessing decoding technique, when considering preparation, measurement, and gate errors in the syndrome extraction procedure, while also accounting for error degeneracy. Our findings indicate a threshold error rate (<inline-formula><tex-math notation="LaTeX">${p_{\text{threshold}}}$</tex-math></inline-formula>) of approximately <inline-formula><tex-math notation="LaTeX">${2\times 10^{-5}}$</tex-math></inline-formula> in the asymptotic limit, while considering realistic noise levels in the mentioned physical procedures.
Atomic physics. Constitution and properties of matter, Materials of engineering and construction. Mechanics of materials
Balaji Venkatesan, Syu-You Guan, Jen-Te Chang
et al.
Abstract Electronic liquid crystal (ELC) phases are spontaneous symmetry breaking states believed to arise from strong electron correlation in quantum materials such as cuprates and iron pnictides. Here, we report a direct observation of a smectic phase in a weakly correlated nonsymmorphic square-net semimetal GdSbxTe2-x. Incommensurate smectic charge modulation and intense local unidirectional nanostructure, which coexist with Dirac fermions across Fermi level, are visualized by using spectroscopic imaging—scanning tunneling microscopy. As materials with highly mobile carriers are mostly weakly correlated, the discovery of such an ELC phase are anomalous and raise questions on the origin of their emergence. Specifically, we demonstrate how chemical substitution generates these symmetry breaking phases before the system undergoes a charge density wave (CDW)—orthorhombic structural transition. Our results highlight the importance of impurities in realizing ELC phases and present a new material platform for exploring the interplay among quenched disorder, Dirac fermions and electron correlation.
Materials of engineering and construction. Mechanics of materials, Atomic physics. Constitution and properties of matter
Abstract The unique geometry of kagome lattices leads to topological features such as flat bands and Dirac cones. When paired with ferromagnetism and a Fermi level near Dirac points, they offer a platform for realizing topological Chern magnetotransport. This prospect recently drew interest in the ferrimagnetic kagome metal TbMn6Sn6. However, density functional theory (DFT) calculations indicate that its 2D Chern gap lies well above the Fermi energy, raising questions about its role in anomalous Hall conductivity. Here, we study YMn6Sn5.45Ga0.55, a structurally and electronically similar material, and find that its intrinsic anomalous Hall effect is three-dimensional. This demonstrates that the Hall response in such compounds does not originate from 2D Chern gaps. Additionally, we confirm that the newly proposed empirical scaling relation for extrinsic Hall conductivity is universally governed by spin fluctuations.
Materials of engineering and construction. Mechanics of materials, Atomic physics. Constitution and properties of matter
Abstract Finding the Kitaev spin liquid in candidate materials involves understanding the entire phase diagram, including other allowed interactions. One of these interactions, called the Gamma (Γ) interaction, causes magnetic frustration and its interplay with the Kitaev (K) interaction is crucial to comprehend Kitaev materials. Due to the complexity of the combined KΓ model, quasi-one-dimensional models have been investigated. While several disordered phases are found in the 2-leg ladder, the nature of the phases are yet to be determined. Here we focus on the disordered phase near the antiferromagnetic Γ limit (denoted by AΓ phase) next to the ferromagnetic Kitaev phase. We report a distinct non-local string order parameter characterizing the AΓ phase, different from the string order parameter in the Kitaev phase. This string order parameter becomes evident only after two unitary transformation, referred to as a twice hidden string order parameter. The related entanglement spectrum, edge states, magnetic field responses, and the symmetry protecting the phase are presented, and its relevance to the two-dimensional Kitaev materials is discussed. Two newly identified disordered phases in the phase diagram of KΓ ladder is also reported.
Materials of engineering and construction. Mechanics of materials, Atomic physics. Constitution and properties of matter
Digital–analog quantum computing (DAQC) offers a promising approach to addressing the challenges of building a practical quantum computer. By efficiently allocating resources between digital and analog quantum circuits, DAQC paves the way for achieving optimal performance. We propose an algorithm designed to enhance the performance of quantum annealing. This method employs a quantum gate to estimate the goodness of the final annealing state and find the ground state of combinatorial optimization problems. We explore two strategies for integrating the quantum annealing circuit into the DAQC framework: (1) state preparation, and (2) embedding within the quantum gate. While the former strategy does not yield performance improvements, we discover that the latter enhances performance within a specific range of annealing time. Algorithms demonstrating enhanced performance utilize the imaginary part of the inner product of two states from different quantum annealing settings. This measure reflects not only the energy of the classical cost function but also the trajectory of the quantum dynamics. This study provides an example of how processing quantum data using a quantum circuit can outperform classical data processing, which discards quantum information.
Atomic physics. Constitution and properties of matter
Kuan-Cheng Chen, Alberto Collauto, Ciarán J Rogers
et al.
Future information processing technologies like quantum memory devices have the potential to store and transfer quantum states to enable quantum computing and networking. A central consideration in practical applications for such devices is the nature of the light-matter interface which determines the storage state density and efficiency. Here, we employ an organic radical, α , γ -bisdiphenylene- β -phenylallyl doped into an o-terphenyl host to explore the potential for using tuneable and high-performance molecular media in microwave-based quantum applications. We demonstrate that this radical system exhibits millisecond-long spin-lattice relaxation and microsecond-long phase memory times at room temperature, while also having the capability to generate an oscillating spin-polarized state using a co-dissolved photo-activated tetraphenylporphyrin moiety, all enabled by using a viscous liquid host. This latest system builds upon collective wisdom from previous molecules-for-quantum literature by combining careful host matrix selection, with dynamical decoupling, and photoexcited triplet-radical spin polarisation to realise a versatile and robust quantum spin medium.
Atomic physics. Constitution and properties of matter, Materials of engineering and construction. Mechanics of materials
New experimental data of angular distribution cross-sections for the 10В(15N,14С)11С reaction at the energy Еlab(15N) = 81 MeV were obtained for the ground states of 14С, 11С nuclei and 2.00 MeV (1/2-), 4.31 MeV (5/2-), 4.31 MeV (3/2-) excited states of 11С nucleus. The experimental data were analyzed within the coupled-reaction-channels (CRC) method. In the CRC calculations, the 15N + 10В Woods - Saxon (WS) optical potential obtained from the CRC analysis of the experimental elastic and inelastic data of these nuclei was used and parameters of the 14С + 11С WS optical potential were deduced from the analysis of the 10В(15N,14С)11С reaction experimental data. Spectroscopic amplitudes of nucleons and cluster transfers were calculated within the translation-invariant shell model.
Atomic physics. Constitution and properties of matter
Most buildings use decorative materials that are aesthetically pleasing, that may contain various amounts of radioactive elements. Thus, the human health of dwellers and workers is continuously exposed to ionizing radiation. Natural radioactivity (238U, 232Th, and 40K) is measured in decorative materials collected from different Iraqi local markets by utilizing a shielded high counting efficiency NaI(Tl) system. Some radiological hazard indexes in all samples were calculated. The results obtained showed that the maximum value of specific activity for 238U, 232Th, and 40K is in decorative stone and the minimum is measured in decorative alabaster. This study concluded that the natural radioactivity and radiological hazard in most samples of decorative materials were within the permissible limits by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the International Commission on Radiological Protection (ICRP), Organization for Economic Co-operation and Development (OECD), and other world reported. Therefore, most samples of decorative materials in the present study can be used without health risks according to radiation scope.
Atomic physics. Constitution and properties of matter
In this study, inelastic and elastic form factors for the low-lying excited states of 10B nucleus were calculated utilizing the nuclear shell model theory. We employed a large-basis psd model space with psdmwk interaction and the harmonic oscillator potential in the form factors calculation. The calculated results with the effective charge are in acceptable agreement with experimental results.
Atomic physics. Constitution and properties of matter
Susan M. Clark, Daniel Lobser, Melissa C. Revelle
et al.
The Quantum Scientific Computing Open User Testbed (QSCOUT) at Sandia National Laboratories is a trapped-ion qubit system designed to evaluate the potential of near-term quantum hardware in scientific computing applications for the U.S. Department of Energy and its Advanced Scientific Computing Research program. Similar to commercially available platforms, it offers quantum hardware that researchers can use to perform quantum algorithms, investigate noise properties unique to quantum systems, and test novel ideas that will be useful for larger and more powerful systems in the future. However, unlike most other quantum computing testbeds, the QSCOUT allows both quantum circuit and low-level pulse control access to study new modes of programming and optimization. The purpose of this article is to provide users and the general community with details of the QSCOUT hardware and its interface, enabling them to take maximum advantage of its capabilities.
Atomic physics. Constitution and properties of matter, Materials of engineering and construction. Mechanics of materials
Abstract We present a theoretical framework for understanding the behavior of the normal and superconducting states of overdoped cuprate high temperature superconductors in the vicinity of the doping-tuned quantum superconductor-to-metal transition. The key ingredients on which we focus are d-wave pairing, a flat antinodal dispersion, and disorder. Even for homogeneous disorder, these lead to effectively granular superconducting correlations and a superconducting transition temperature determined in large part by the superfluid stiffness rather than the pairing scale.
Materials of engineering and construction. Mechanics of materials, Atomic physics. Constitution and properties of matter
Abstract Recently monolayer jacutingaite (Pt2HgSe3), a naturally occurring exfoliable mineral, discovered in Brazil in 2008, has been theoretically predicted as a candidate quantum spin Hall system with a 0.5 eV band gap, while the bulk form is one of only a few known dual-topological insulators that may host different surface states protected by symmetries. In this work, we systematically investigate both structure and electronic evolution of bulk Pt2HgSe3 under high pressure up to 96 GPa. The nontrivial topology is theoretically stable, and persists up to the structural phase transition observed in the high-pressure regime. Interestingly, we found that this phase transition is accompanied by the appearance of superconductivity at around 55 GPa and the critical transition temperature T c increases with applied pressure. Our results demonstrate that Pt2HgSe3 with nontrivial topology of electronic states displays a ground state upon compression and raises potentials in application to the next-generation spintronic devices.
Materials of engineering and construction. Mechanics of materials, Atomic physics. Constitution and properties of matter