Interaction Hamiltonian Research Articles

Quantitative profiling of the vaginal microbiota improves resolution of the microbiota-immune axis.

The composition of the vaginal microbiota is closely linked to adverse sexual and reproductive health outcomes, due in part to effects on genital immunology. Compositional approaches such as metagenomic sequencing provide a snapshot of all bacteria in a sample and have become the standard for characterizing the vaginal microbiota, but only provide microbial relative abundances. We hypothesized that the addition of absolute abundance data would provide a more complete picture of host-microbe interactions in the female genital tract. We analyzed cervicovaginal secretions from 196 female sex workers in Kenya and found that bacterial load was elevated among women with diverse, bacterial vaginosis (BV)-type microbiota and lower among women with Lactobacillus predominance. Bacterial load was also positively associated with proinflammatory cytokines, such as IL-1α, and negatively associated with chemokines, such as IP-10. The associations between bacterial load and immune factors differed across bacterial community states, but L. crispatus predominance was the only microbial community where higher bacterial load was not associated with higher proinflammatory cytokines. Total vaginal bacterial load was also a stronger predictor of the genital immune environment than BV by Nugent score, the current clinical standard, in the Kenya-based cohort and in a Uganda-based confirmatory cohort. Our results suggest that total vaginal bacterial load is at least as strong a predictor of the genital immune milieu as current BV clinical diagnostic tools, supporting exploration of the vaginal bacterial load as a predictor of adverse reproductive and sexual health outcomes. Video Abstract.

Stability Frontiers in the AM6X6 Kagome Metals: The LnNb6Sn6 (Ln:Ce-Lu,Y) Family and Density-Wave Transition in LuNb6Sn6.

The kagome motif is a versatile platform for condensed matter physics, hosting rich interactions between magnetic, electronic, and structural degrees of freedom. In recent years, the discovery of a charge density wave (CDW) in the AV3Sb5 superconductors and structurally-derived bond density waves (BDW) in FeGe and ScV6Sn6 have stoked the search for new kagome platforms broadly exhibiting density wave (DW) transitions. In this work, we evaluate the known AM6X6 chemistries and construct a stability diagram that summarizes the structural relationships among the >125 member family. Subsequently, we introduce our discovery of the broader LnNb6Sn6 (Ln:Ce-Nd,Sm,Gd-Tm,Lu,Y) family of kagome metals and an analogous DW transition in LuNb6Sn6. Our X-ray scattering measurements clearly indicate a (1/3, 1/3, 1/3) ordering wave vector ( superlattice) and diffuse scattering on half-integer L-planes. Our analysis of the structural data supports the "rattling mode" DW model proposed for ScV6Sn6 and paints a detailed picture of the steric interactions between the rare-earth filler element and the host Nb-Sn kagome scaffolding. We also provide a broad survey of the magnetic properties within the HfFe6Ge6-type LnNb6Sn6 members, revealing a number of complex antiferromagnetic and metamagnetic transitions throughout the family. This work integrates our new LnNb6Sn6 series of compounds into the broader AM6X6 family, providing new material platforms and forging a new route forward at the frontier of kagome metal research.

Constructing an integrable spin–boson model with open boundary conditions

Abstract We investigate the integrability of the Rabi model, which is traditionally viewed as not Yang-Baxter integrable despite its solvability. Building on efforts by Bogoliubov, Amico, Batchelor, and Zhou, who explored special limiting cases of the model, we develop a spin-boson interaction Hamiltonian under more general boundary conditions, particularly focusing on open boundary conditions with off-diagonal terms. Our approach maintains the direction of the spin in the $z$ direction, and also preserves the boson particle number operator $a^\dagger a$, marking a progression beyond previous efforts that have primarily explored reduced forms of the Rabi model from Yang-Baxter algebra.
We also address the presence of ``unwanted" quadratic boson terms $a^2$ and $a^\dagger{}^2$, which share coefficients with the boson particle number operator. Interestingly, these terms vanish when spectral parameter $u = \pm \theta_s$, simplifying the model to a limiting case of operator-valued twists, a scenario previously discussed by Batchelor and Zhou.

Bath dynamical decoupling with a quantum channel

Abstract Bang–bang dynamical decoupling protects an open quantum system from decoherence due to its interaction with the surrounding bath/environment. In its standard form, this is achieved by strongly kicking the system with cycles of unitary operations, which average out the interaction Hamiltonian. In this paper, we generalize the notion of dynamical decoupling to repeated kicks with a quantum channel, which is applied to the bath. We derive necessary and sufficient conditions on the employed quantum channel and find that bath dynamical decoupling works if and only if the kick is ergodic. Furthermore, we study in which circumstances completely positive trace-preserving (CPTP) kicks on a mono-partite quantum system induce quantum Zeno dynamics with its Hamiltonian cancelled out. This does not require the ergodicity of the kicks, and the absence of decoherence-free subsystems is both necessary and sufficient. While the standard unitary dynamical decoupling is essentially the same as the quantum Zeno dynamics, our investigation implies that this is no longer true in the case of CPTP kicks. To derive our results, we prove some spectral properties of ergodic quantum channels, that might be of independent interest. Our approach establishes an enhanced and unified mathematical understanding of several recent experimental demonstrations and might form the basis of new dynamical decoupling schemes that harness environmental noise degrees of freedom.

Decoherence-free many-body Hamiltonians in nonlinear waveguide quantum electrodynamics

Enhancing interactions in many-body quantum systems, while protecting them from environmental decoherence, is at the heart of many quantum technologies. Waveguide quantum electrodynamics is a promising platform for achieving this, as it hosts infinite-range interactions and decoherence-free subspaces of quantum emitters. However, as coherent interactions between emitters are typically washed out in the wavelength-spacing regime hosting decoherence-free states, coherent control over the latter becomes limited, and many-body Hamiltonians in this important regime remain out of reach. Here we show that by incorporating emitter arrays with nonlinear waveguides hosting parametric gain, we obtain a unique class of many-body interaction Hamiltonians with coupling strengths that increase with emitter spacing, and persist even for wavelength-spaced arrays. We then propose to use these Hamiltonians to coherently generate decoherence-free states directly from the ground state, using only global squeezing drives, without the need for local addressing of individual emitters. Interestingly, we find that the dynamics approaches a unitary evolution in the limit of weak intrawaveguide squeezing, and we discuss potential experimental realizations of this effect. Our results pave the way towards coherent control protocols in waveguide quantum electrodynamics, with applications including quantum computing, simulation, memory, and nonclassical light generation. Published by the American Physical Society 2025

Optimization of digital back-propagation for coherent optical fiber communication systems using fourth-order Runge-Kutta in the interaction picture method.

The digital back-propagation (DBP) is an algorithm that can equalize the chromatic dispersion and nonlinearity in the coherent optical fiber communication system. However, the nonlinear equalization effect of traditional split-step Fourier method (SSFM)-based DBP is limited. This paper replaces the SSFM in DBP algorithm with the fourth-order Runge-Kutta in the interaction picture (RK4IP) method, and employs the Bayesian optimization algorithm (BOA) to optimize the coefficients in RK4IP-based DBP algorithm, then compares it with SSFM-based DBP algorithm, which is also optimized using BOA. The experimental results of 9×100 km standard single-mode fiber (SSMF) 20 Gbaud 16QAM transmission system demonstrate that the coefficient-optimized RK4IP (CO-RK4IP)-based DBP algorithm can achieve the maximum improvement of 0.89 dB in the Q-factor compared to the coefficient-optimized SSFM (CO-SSFM)-based DBP algorithm at equivalent complexity, proving that CO-RK4IP is an effective recursive method for DBP algorithm.

MapTurns: mapping the structure, H-bonding, and contexts of beta turns in proteins.

Beta turns are the most common type of secondary structure in proteins after alpha helices and beta sheets and play many key structural and functional roles. Turn backbone (BB) geometry has been classified at multiple levels of precision, but the current picture of side chain (SC) structure and interaction in turns is incomplete, because the distribution of SC conformations associated with each sequence motif has commonly been represented only by a static image of a single, typical structure for each turn BB geometry, and only motifs which specify a single amino acid (e.g. aspartic acid at turn position 1) have been systematically investigated. Furthermore, no general evaluation has been made of the SC interactions between turns and their BB neighborhoods. Finally, the visualization and comparison of the wide range of turn conformations has been hampered by the almost exclusive characterization of turn structure in BB dihedral-angle (Ramachandran) space. This work introduces MapTurns, a web server for motif maps, which employ a turn-local Euclidean-space coordinate system and a global turn alignment to comprehensively map the distributions of BB and SC structure and H-bonding associated with sequence motifs in beta turns and their local BB contexts. Maps characterize many new SC motifs, provide detailed rationalizations of sequence preferences, and support mutational analysis and the general study of SC interactions, and they should prove useful in applications such as protein design. MapTurns is available at www.betaturn.com. Sample code is available at: https://github.com/nenewell/MapTurns/tree/main.

UNTANGLING THE VALLEY STRUCTURE OF STATES FOR INTRAVALLEY EXCHANGE ANISOTROPY IN LEAD CHALCOGENIDES QUANTUM DOTS

We put forward a generalized procedure which allows to restore the bulk-like electron and hole wave functions localized in certain valleys from the wave functions of quantum confined electron/hole states obtained in atomistic calculations of nanostructures. The procedure is applied to the lead chalcogenide quantum dots to accurately extract the intravalley velocity matrix elements and the constants of the effective intravalley Hamiltonian of the exchange interaction for the ground exciton state in PbS and PbSe quantum dots. Our results suggest that intravalley parameters in PbS quantum dots are much more anisotropic than the ones in PbSe. Renormalization of the velocity matrix elements, forbidden band gap, valley and exchange splittings of exciton and exciton binding energy are also calculated.

Photoinduced Melting of V4O7 Correlated State

AbstractThe compound V4O7 is one of the Magnéli phase (VnO2n − 1, n = 3, 4, …, 9) correlated vanadium oxides with distinct intriguing electronic and structural properties. The possibility to manipulate the phase state of V4O7 on an ultrafast time scale by light makes this material promising for potential applications in photonics, optoelectronics, quantum, and neuromorphic circuit design. In this work, the ultrafast spectroscopy of V4O7 reveals the second‐order nature of the photoinduced insulator‐to‐metal transition, emphasizing electronic and lattice contributions. The findings reveal the influence of the laser excitation level and temperature on these dynamics, providing a comprehensive understanding of V4O7 structural changes and response to external stimuli. The phenomenological model based on the Landau–Ginzburg formalism provides a robust framework for explaining the photoinduced transition dynamics, showing a detailed picture of the light interaction with the electronic and lattice subsystems. This integrated approach significantly enhances the understanding of V4O7 complex behavior upon photoexcitation, opening new possibilities for developing new optoelectronic devices and noninvasive optical control of the phase transition pathways in vanadates.

The Influence of MuseScore Software on Students' Creative Thinking in Music

ABSTRACTAs pedagogical training becomes more advanced and intensive, new methods of instruction that incorporate information technology are becoming increasingly important. The purpose of this article is to investigate how using the MuseScore scorewriter to teach solfeggio affects music students' ability to think creatively. The program designed for a quasi‐experimental study was implemented with two groups of students (N = 87) at the Conservatory of Music, Ningbo University. One group used the MuseScore scorewriter to practice solfeggio during weekly music lessons, while the other group used written notation. A mixed within/between‐subject ANOVA test was used to examine students' mean pre‐and post‐test scores. The analysis revealed significant differences in total scores between the mean pre‐and post‐test scores. The experimental group significantly improved their creative thinking scores due to the intervention, whereas the control group showed only minor changes. More research is required to gain a fuller picture of music students' interactions with music technology and how they view its use in the classroom. Future research should expand on these findings by delving deeper into the reasons and motivations behind musicians' technology usage decisions, as well as the innovative ways in which they incorporate technology into their teaching methods.

A new solution to the Callan Rubakov effect

In this paper we study the scattering of massive fermions off of smooth, spherically symmetric monopoles in 4d SU(2) gauge theory. We propose a complete physical picture of the monopole-fermion interaction which encompasses all angular momentum modes. We show that as an in-going fermion scatters off a monopole, it excites trapped W-bosons in the monopole core by a version of the Witten effect so that the monopole can accrue charge and transform into a dyon at parametrically low energies. The imparted electric charge is then protected from decay by an emergent ℤN generalized global symmetry, creating a stable dyon. At sufficiently low energies, the scattered fermion can be trapped by the dyon’s electrostatic potential, forming a bound state, which can decay into spherically symmetric fermion modes subject to the preserved ℤN global symmetry. We propose that monopole-fermion scattering can be described in this way without needing to add “new” states to the Hilbert space, thereby eliminating a long standing confusion in the Callan Rubakov effect.

Gender Differences in Immersive Reading With Interactive Electronic Picture Books

This study examined the effectiveness of interactive electronic picture (IEP) books during immersive reading, impact on mental health education, and integrating gaming elements in educational settings. The mixed-methods experiment combined quantitative data from surveys with qualitative insights from in-depth interviews. The findings revealed that males have higher levels of immersion during interactive reading. This study contributes to digital learning by providing empirical evidence on the benefits of integrating interactive technology into education as well as emphasizing IEP books’ potential to revolutionize mental health education and the importance of considering gender differences when designing educational tools.

Quantum Gates with Different Robust Merits

AbstractA protocol for implementing a universal set of quantum gates, which are safeguarded from noise through geometric, dephasing‐free, and dynamical‐decoupling approaches is proposed. With properly designed Hamiltonians, the desired interactions are realized directly within the Schrödinger picture rather than relying on the interaction picture. This design confers two advantages. One is that the system's evolution remains continuously protected by the noise‐mitigation strategies at every stage, eliminating the need to revert to the Schrödinger picture. The other one is that the dynamical decoupling technique effectively averages out small residual free terms in the system's Hamiltonian, thus reducing the stringent requirements for precise control of system parameters to avoid errors. Furthermore, numerical results are presented to support our protocol by finding gate fidelities in the absence (presence) of noises or errors, without or with dynamical decoupling technique.

The interaction between modality and negation in Turkish

Abstract This paper investigates the scope interaction between modality and negation in Turkish. We observe that modals display a complex picture of scope interaction with negation: both possibility and necessity modals can have scope above or under negation on the one hand and both epistemic and root modals can take wide scope over or narrow scope under negation. This suggests that modals are interpreted in accordance with modal relations, bases, and sources closely associated with discourse and pragmatic factors, but not with lexical idiosyncrasies through which modals are classified as Modal1, Modal2. The study also presents empirical evidence for the idea that scope relations are determined by syntactic structure, indicating that complex grammatical operations are unnecessary to maintain the linear order of the sentence. This suggests that Turkish exhibits scope rigidity in syntax-semantics interface, a situation also noted for scope relations between NPIs and negation. For otherwise cases where scope relations are not read off syntactically, we offer LF movement of negation to a higher position, an operation which has already been introduced for independent grammatical phenomena such as NPI licensing. Hence, there is no need to postulate overt or covert head movement of modals to structurally higher positions to outscope negation.

Treelike process tensor contraction for automated compression of environments

The algorithm “automated compression of environments” (ACE) [M. Cygorek , ] provides a versatile way of simulating an extremely broad class of open quantum systems. This is achieved by encapsulating the influence of the environment, which is determined by the interaction Hamiltonian(s) and initial states, into compact process tensor matrix product operator (PT-MPO) representations. The generality of the ACE method comes at high numerical cost. Here, we demonstrate that orders-of-magnitude improvement of ACE is possible by changing the order of PT-MPO contraction from a sequential to a treelike scheme. The problem of combining two partial PT-MPOs with large inner bonds is solved by a preselection approach. The drawbacks of the preselection approach are that the MPO compression is suboptimal and that it is more prone to error accumulation than sequential combination and compression. We therefore also identify strategies to mitigate these disadvantages by fine-tuning compression parameters. This results in a scheme that is similar in compression efficiency and accuracy to the original ACE algorithm, yet is significantly faster. Our numerical experiments reach similar conclusions for bosonic and fermionic test cases, suggesting that our findings are characteristic of the combination of PT-MPOs more generally. Published by the American Physical Society 2024

Developing the Interactive Game-Based Picture Book "Food Ninja" to Enhance Creativity in Elementary School Students

Developing the Interactive Game-Based Picture Book "Food Ninja" to Enhance Creativity in Elementary School Students

A comprehensive study on H2 loading/deloading with PdAg alloy thin films using in-situ synchrotron radiation X-ray diffraction

The present study gives a comprehensive picture of interaction of hydrogen with Pd0.54Ag0.46 and Pd0.88Ag0.12 alloy thin films, at RT, 50 °C, 100 °C, 150 °C and200 °C, based on the experiments reported in the present work. During hydrogenation, the diffraction peaks shifted towards a lower angle, indicating an expansion of the lattice due to hydrogen incorporation revealed by in-situ synchrotron XRD. The cycles of hydrogen absorption and desorption were fully reversible, and no hysteresis was observed in the synthesized films. Our experiments suggest that at room temperature the magnitude of peak-shift on hydrogenation is larger with lower concentrations of Ag in Pd. Additionally, the interaction of PdAg alloy with hydrogen was observed to be temperature dependent. Increased hydrogenation temperature reduces the hydrogen sticking coefficient, reducing the peak shift magnitude for both samples. Additionally, at higher temperatures, hydrogen absorption is higher in Pd54Ag46 having smaller crystallite sizes than in Pd88Ag12.

Crystallographic insights into lipid-membrane protein interactions in microbial rhodopsins.

The primary goal of our work is to provide structural insights into the influence of the hydrophobic lipid environment on the membrane proteins (MPs) structure and function. Our work will not cover the well-studied hydrophobic mismatch between the lipid bilayer and MPs. Instead, we will focus on the less-studied direct molecular interactions of lipids with the hydrophobic surfaces of MPs. To visualize the first layer of amphiphiles surrounding MPs and analyze their interaction with the proteins, we use the available highest-quality crystallographic structures of microbial rhodopsins. The results of the structure-based analysis allowed us to formulate the hypothetical concept of the role of the nearest layer of the lipids as an integral part of the MPs that are important for their structure and function. We then discuss how the lipid-MPs interaction is influenced by exogenous hydrophobic molecules, noble gases, which can compete with lipids for the surface of MPs and can be used in the systematic approach to verify the proposed concept experimentally. Finally, we raise the problems of currently available structural data that should be overcome to obtain a more profound picture of the lipid-MP interactions.

Verification of electromagnetic simulation capabilities in global gyrokinetic particle-in-cell code GTS

Recently, the numerical scheme presented by Mishchenko et al. [Phys. Plasmas 21, 052113 (2014); 21, 092110 (2014)] enabled explicit gyrokinetic simulations of low-frequency electromagnetic instabilities in tokamaks at experimentally relevant values of plasma β. This scheme resolved the long-standing cancellation problem that previously hindered gyrokinetic particle-in-cell code simulations of magnetohydrodynamic phenomena with inherently small parallel electric fields. Moreover, the scheme did not employ approximations that eliminate critical tearing-type instabilities. Here, we report on the implementation of this numerical scheme in the global gyrokinetic particle-in-cell code GTS. This implementation allows for a more complete and accurate picture of interaction between small scale turbulence and MHD modes in tokamaks. Additionally, we present a comprehensive set of verification simulations of numerous electromagnetic instabilities relevant to present-day tokamaks. These simulations encompass the kinetic ballooning mode, the internal kink mode, the tearing mode, the micro-tearing mode, and the toroidal Alfven eigenmode destabilized by energetic ions, which are all instrumental in understanding tokamak physics. We will also showcase the preliminary nonlinear simulations of kinetic ballooning instabilities and (2,1) island formation due to tearing mode instability. These simulations validate the accuracy of the scheme implementation and pave the way for studying how these instabilities affect plasma confinement and performance.

Flavor neutrinos as unstable particles: an interaction picture view

Flavor neutrinos as unstable particles: an interaction picture view