cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Dark Matter Catalyzed Baryon Destruction
Creators: name: Ema, Yohei
name: McGehee, Robert
name: Pospelov, Maxim
name: Ray, Anupam
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: WIMP-type dark matter may have additional interactions that break baryon number, leading to induced nucleon decays which are subject to direct experimental constraints from proton decay experiments. In this work, we analyze the possibility of continuous baryon destruction, deriving strong limits from the dark matter accumulating inside old neutron stars, as such a process leads to excess heat generation. We construct the simplest particle dark matter model that breaks baryon and lepton numbers separately but conserves $B-L$. Virtual exchange by DM particles in this model results in di-nucleon decay via $nn\to n\barν$ and $np\to ne^+$ processes.
description: v2: 9 pages, 3 figures. Minor changes (text improved), Conclusions Unchanged. Matches version published in PRD
Lösungsorientierung o d e r Problemorientierung? Kompetenzorientierung o d e r Defizitorientierung? Jede Frage, die ein Gutachter, Berater oder Therapeut stellt, ist schon eine Intervention!
Creators: name: Himmelreich, Arndt
Publisher: name: Leibniz Institut für Psychologie (ZPID)
Year: 2001
Subjects: subject: Verkehrspsychologie
subject: Psychoanalyse
subject: Verkehrstherapie
subject: Fahreignungsbegutachtung
subject: Systemtherapie
subject: lösungsorientierte Kurzzeittherapie
subject: Hypnotherapie
subject: Driver Improvement
subject: 150

description: Vortrag von Arndt Himmelreich. Thema: Lösungsorientierung bzw. Problemorientierung in der Verkehrstherapie. Ambivalenz-Coaching: hypno-systemische Methoden zur Erhöhung der Rollen- und Kontextflexibilität durch Offenlegung innerer Konflikte (konstruktive, sinnlich faßbare Externalisierung der "mich innerlich auffressenden Monster") nach Milton H. Erickson und Gunther Schmidt; Balance von lösungsorientierter ("Ab-Lösung von dem hypnotisch starren Blick auf das Problem") mit eben auch der problemorientierten ("Würdigung des Leids") Kurzzeit-Beratung (Gunther Schmidts Veränderung des Modells von Steve de Shazer und Insoo Kim Berg); Kundenorientierung und Erstgespräche in Begutachtungsstellen, Beratungen, Therapien sowie auch in Behörden (Burn-out-Prophylaxe) - Die geschichtlichen Phasen der Fahreignungsdiagnostik in Deutschland (mit Zukunftsprognose): Kann eine Begutachtungssituation (MPU) "therapieähnlich" sein? Quelle: Driver Improvement. 7. Internationaler Kongress. Ausgewählte Beiträge. 8. bis 10. Oktober 2001 in Salzburg. Hg. v. E. Panosch. Veranstaltet von Kuratorium für Verkehrssicherheit (KfV), Wien, Österreich, Bundesanstalt für Straßenwesen (BASt), Bergisch Gladbach, Deutschland, Schweizerische Beratungsstelle für Unfallverhütung (bfu), Bern, Schweiz. [Herausgeber: Kuratorium für Verkehrssicherheit (KfV) am Kuratorium für Schutz und Sicherheit, Wien.] Wien (Druck und Verleger: Kuratorium für Schutz und Sicherheit, Wien) 2002, S. 289-321
Ratchet Loading and Multi-Ensemble Operation in an Optical Lattice Clock
Creators: name: Hassan, Youssef S.
name: Kobayashi, Takumi
name: Bothwell, Tobias
name: Seigel, Jacob L.
name: Hunt, Benjamin D.
name: Beloy, Kyle
name: Gibble, Kurt
name: Grogan, Tanner
name: Ludlow, Andrew D.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We demonstrate programmable control over the spatial distribution of ultra-cold atoms confined in an optical lattice. The control is facilitated through a combination of spatial manipulation of the magneto-optical trap and atomic population shelving to a metastable state. We first employ the technique to load an extended (5 mm) atomic sample with uniform density in an optical lattice clock, reducing atomic interactions and realizing remarkable frequency homogeneity across the atomic cloud. We also prepare multiple spatially separated atomic ensembles and realize multi-ensemble clock operation within the standard one-dimensional (1D) optical lattice clock architecture. Leveraging this technique, we prepare two oppositely spin-polarized ensembles that are independently addressable, offering a platform for implementing spectroscopic protocols for enhanced tracking of local oscillator phase. Finally, we demonstrate a relative fractional frequency instability at one second of $2.4(1) \times10^{-17}$ between two ensembles, useful for characterization of intra-lattice differential systematics.
description: 10 pages, 6 figures
Polarization modes of gravitational waves in general Einstein-vector theory
Creators: name: Lai, Xiao-Bin
name: Dong, Yu-Qi
name: Liu, Yu-Qiang
name: Liu, Yu-Xiao
Publisher: name: arXiv
Year: 2024
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the polarization modes of gravitational waves in general Einstein-vector theory with an arbitrary constant background vector field under a Minkowski background. We compare these polarization modes with those of other vector-tensor theories and constrain the parameter spaces based on the gravitational-wave event GW170817 with its electromagnetic counterpart GRB170817A and observations of pulsar timing arrays. The presence of the background vector field leads to the anisotropy of space and a rich variety of gravitational wave contents. Our results reveal that the polarization modes of gravitational waves depend on the parameter spaces. There are at least two and at most five independent polarization modes in one parameter space. In different parameter spaces, some mixture modes are allowed, including tensor-vector, tensor-scalar, tensor-vector-scalar, vector-scalar, and scalar-scalar mixture modes, as well as five independent modes (excluding $P_l$): $P_+$, $P_{\times}$, $P_x$, $P_y$, and $P_b$. In all regions of the parameter spaces, there are always two tensor modes, which can be either independent of or mixed with other modes. The independent $P_b$ mode consistently exhibits the same speed as light. If the speed of tensorial gravitational waves strictly equals that of light, only the $P_+$, $P_{\times}$, and $P_b$ modes are permitted. Furthermore, through comparisons of some vector-tensor theories and based on the observations of gravitational waves, the $P_b$ mode is expected to be allowed.
Single-beam grating-chip 3D and 1D optical lattices
Creators: name: Bregazzi, Alan
name: McGilligan, James P.
name: Griffin, Paul F.
name: Riis, Erling
name: Arnold, Aidan S.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Ultracold atoms are crucial for unlocking truly precise and accurate quantum metrology, and provide an essential platform for quantum computing, communication and memories. One of the largest ongoing challenges is the miniaturization of these quantum devices. Here, we show that the typically macroscopic optical lattice architecture at the heart of many ultra-precise quantum technologies can be realized with a single input laser beam on the same diffractive chip already used to create the ultracold atoms. Moreover, this inherently ultra-stable platform enables access to a plethora of new lattice dimensionalities and geometries, ideally suited for the design of high-accuracy, portable quantum devices.
description: 7 pages, 3 figures, Supplementary Material, to appear in Phys. Rev. Lett
Effective short distance interaction in Calogero-Sutherland quantum fluids
Creators: name: Bottesi, Federico L.
name: Zemba, Guillermo R.
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We consider the effective conformal field theory with symmetry W-infinity x W-infinity that describes the thermodynamic limit of the Calogero-Sutherland model. In the repulsive regime of the free fermion formulation, we identify an attractive interaction between opposite moving particle-hole pairs that dominates the short distance behavior and that is proposed as responsible for the destabilization of the ground state, leading to a new one of bosonic nature. The process is described by a Bogoliubov transformation of the free fermion bilinear operators into bosonic ones, preserving the form of the W-infinity algebra but decoupling the opposite chirality terms in the hamiltonian, as expected in the low energy limit. In coordinate space this interaction has a short range component that arises due to the quantum regularization of the theory. The described dynamical process may be considered as a mechanism of the emergence of the known charge and quantum statistics fractionalization of the low lying excitations of the theory, as predicted in both first and second quantization studies.
description: 9 pages. arXiv admin note: text overlap with arXiv:2404.10011
Empirische Generalisierung Vs. ,Einfachheit'. Zur Zuordnung Zwischen Formalen Und Logischen Eigenschaften Von Sätzen Im Deutschen
Creators: name: Höhle, Tilman N.
Publisher: name: Zenodo
Year: 2018

description: Empirische Generalisierung vs. ,Einfachheit‘. Zur Zuordnung zwischen formalen und logischen Eigenschaften von Sätzen im Deutschen
Regularizing infrared divergences in de Sitter spacetime: Loops, dimensional regularization, and cutoffs
Creators: name: Huenupi, Javier
name: Hughes, Ellie
name: Palma, Gonzalo A.
name: Sypsas, Spyros
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Correlation functions of light scalar fields in de Sitter spacetime, computed via standard perturbation theory, often exhibit secular growth characterized by time-dependent divergent terms in the form of powers of $\ln a(t)$, where $a(t)$ is the scale factor describing cosmic expansion. It is widely believed that loop corrections further enhance this secular growth. We argue that this is not necessarily the case: Loop corrections can be systematically handled using standard perturbative techniques, such as dimensional regularization, without introducing new $\ln a(t)$ terms. We focus on a canonical massless scalar field $φ$ with self-interactions described by a potential $\mathcal{V}(φ)$, and analyze correlation functions represented by diagrams with a single vertex and an arbitrary number of loops. In this framework, infrared divergences can be systematically eliminated with counterterms at each order in perturbation theory, leading to loop-corrected correlation functions that are indistinguishable from their tree-level forms, with no secular growth from loops. Furthermore, adopting a Wilsonian perspective, we explore the role of cutoffs in computing loop corrections within effective field theory and identify the effective potential $\mathcal{V}_{\rm eff}(φ)$, which guarantees cutoff-independent observables. We conclude that when infrared comoving cutoffs are used to regularize loop integrals, time-dependent Wilsonian coefficients are necessary to maintain cutoff-free correlation functions. Neglecting this time dependence results in secular growth from loops.
description: 13 pages + references. V3: fixed typos, added several clarifications and refs. Matches published version
D2.2: Report On Users' Needs And Technical Requirements
Creators: name: Paoli, Stefano
name: Forbes, Paula
Publisher: name: Zenodo
Year: 2015

description: The Deliverable D2.2 – STEP User and Technical Requirements - is part of the Work Package 2 Requirements and Analysis. The purpose of this deliverable is to present the research activities conducted for the definition of user and technical requirements for the STEP Platform. The intended audience for this deliverable is preliminarily the project partners. However the research work conducted for the definition of requirements will be of interest for a wider audience (e.g. policy makers, researchers, the public).
Parameterized quasinormal frequencies and Hawking radiation for axial gravitational perturbations of a holonomy-corrected black hole
Creators: name: Yang, Sen
name: Guo, Wen-Di
name: Tan, Qin
name: Zhao, Li
name: Liu, Yu-Xiao
Publisher: name: arXiv
Year: 2024
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: As the fingerprints of black holes, quasinormal modes are closely associated with many properties of black holes. Especially, the ringdown phase of gravitational waveforms from the merger of compact binary components can be described by quasinormal modes. Serving as a model-independent approach, the framework of parameterized quasinormal frequencies offers a universal method for investigating quasinormal modes of diverse black holes. In this work, we first obtain the Schrödinger-like master equation of the axial gravitational perturbation of a holonomy-corrected black hole. We calculate the corresponding quasinormal frequencies using the Wentzel-Kramers-Brillouin approximation and asymptotic iteration methods. We investigate the numerical evolution of an initial wave packet on the background spacetime. Then, we deduce the parameterized expression of the quasinormal frequencies and find that $r_0 \leq 10^{-2}$ is a necessary condition for the parameterized approximation to be valid. We also study the impact of the quantum parameter $r_0$ on the greybody factor and Hawking radiation. With more ringdown signals of gravitational waves detected in the future, our research will contribute to the study of the quantum properties of black holes.
description: 14 pages,6 figures,and 8 tables
Enhanced particle acceleration in a pulsar wind interacting with a companion
Creators: name: Richard-Romei, Valentina
name: Cerutti, Benoît
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Pulsar winds have been shown to be preferred sites of particle acceleration and high-energy radiation. Numerous studies have been conducted to better characterize the general structure of such relativistic plasmas in isolated systems. However, many pulsars are found in binary systems and there are currently no ab initio models available that would include both the pulsar magnetosphere and the wind of the pulsar in interaction with a spherical companion. We investigate the interaction between a pulsar wind and a companion to probe the rearrangement of the pulsar wind, assess whether it leads to an enhancement of particle acceleration, and predict the high-energy radiative signature that stems from this interaction. We perform two-dimensional equatorial particle-in-cell simulations of an inclined pulsar surrounded by a spherical, unmagnetized, perfectly conducting companion settled in its wind. We find that the presence of the companion significantly alters the structure of the wind. When the companion lies beyond the fast magnetosonic point, a shock is established and the perturbations are advected in a cone behind the companion. We observe an enhancement of particle acceleration due to forced reconnection as the current sheet reaches the companion surface. Hence, high-energy synchrotron radiation is also amplified. The orbital light curves display two broad peaks reaching up to 14 times the high-energy pulsed flux emitted by an isolated pulsar magnetosphere. These effects increase with the growth of the companion size and with the decrease of the pulsar-companion separation. The present study suggests that a pulsar wind interacting with a companion induces a significant enhancement of high-energy radiation that takes the form of an orbital-modulated hollow cone of emission, which should be detectable by galactic-plane surveys, possibly with long-period radio transient counterparts.
description: 11 pages, 11 figures, accepted for publication in Astronomy and Astrophysics, few corrections to match the published version
Substrate interference and strain in the second harmonic generation from MoSe$_2$ monolayers
Creators: name: Puri, S.
name: Patel, S.
name: Cabellos, J. L.
name: Rosas-Hernandez, L. E.
name: Barraza-Lopez, S.
name: Mendoza, B.
name: Nakamura, H.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Nonlinear optical materials of atomic thickness--such as non-centrosymmetric 2H transition metal dichalcogenide monolayers--have a second order nonlinear susceptibility ($χ^{(2)}$) whose intensity can be tuned by strain. However, whether $χ^{(2)}$ is enhanced or reduced by tensile strain is a subject of conflicting reports. Here, we grow high-quality MoSe$_2$ monolayers under controlled biaxial strain created by two different substrates, and study their linear and non-linear optical responses with a combination of experimental and theoretical approaches. A 15-fold overall enhancement in second harmonic generation (SHG) intensity is observed on MoSe$_2$ monolayers grown on SiO$_2$ when compared to its value when on a Si$_3$N$_4$ substrate. A seven-fold enhancement was ascertained to substrate interference, and a factor of two to the enhancement of $χ^{(2)}$ arising from biaxial strain: substrate interference and strain are independent handles to engineer the SHG strength of non-centrosymmetric 2D materials.
Holographic mean field theory and Kondo lattice
Creators: name: Han, Young-Kwon
name: Ghorai, Debabrata
name: Yuk, Taewon
name: Sin, Sang-Jin
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We first study a non-relativistic field theory model for the Kondo lattice by introducing the Kondo condensation, whose main effect is the hybridization of the flat band of the localized electron with dispersive one of the itinerant electron. The problem here is that the resulting Kondo condensation arises only in strong coupling where the validity of the mean field theory is questionable. Therefore, we build a holographic mean field theory of the Kondo lattice with strong coupling by identifying the effect of the lattice with the fermion's spectral shape due to the coupling with the order parameter representing the symmetry breaking. For the flat band spectrum we use the mixed quantization, and for the dispersive spectrum we intoduce the second fermion in standard quantization. The coupling of the two fermions with the scalar order representing the Kondo condensation provides the hybrization of the two spectrum, reproducing the main feature of the Kondo lattice together with the fuzzy character of the spectrum of the strongly coupled system.
On Measuring Distances in the Quantum Gravity Landscape
Creators: name: Mohseni, Amineh
name: Montero, Miguel
name: Vafa, Cumrun
name: Valenzuela, Irene
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this note, we propose a generalized notion of distance between vacua in the theory of a scalar field $ϕ$ with scalar potential $V(ϕ)$ coupled to gravity. We propose the normalized tension of domain wall connecting different field values, with a varying normalization relative to a local energy scale, as the distance. We show this definition reproduces the usual moduli space distance for zero potential, as well as the $d\propto |\log Λ|$ behavior with the vacuum energy $Λ$ in the AdS case, previously proposed in the literature. In the case of large AdS we also obtain the expected exponent of mass versus distance in one particular case, when the mass of the light tower is $m\sim \sqrt Λ$ and there is a single extra dimension decompactifying. We also discuss the features and shortcomings of alternative but related proposals.
description: 27 pages, 3 figures, typos corrected, comments added, references added, published version
Modular properties of massive scalar partition functions
Creators: name: Aggarwal, Ankit
name: Barnich, Glenn
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We compute the exact thermal partition functions of a massive scalar field on flat spacetime backgrounds of the form $\mathbb R^{d-q}\times \mathbb T^{q+1}$ and show that they possess an ${\rm SL}(q+1,\mathbb Z)$ symmetry. Non-trivial relations between equivalent expressions for the result are obtained by doing the computation using functional, canonical and worldline methods. For $q=1$, the results exhibit modular symmetry and may be expressed in terms of massive Maass-Jacobi forms. In the complex case with chemical potential for ${\rm U}(1)$ charge turned on, the usual discussion of relativistic Bose-Einstein condensation is modified by the presence of the small dimensions.
description: 35 pages Latex file
Theory of spin and orbital charge conversion at the surface states of Bi_{1-x}Sb_x topological insulator
Creators: name: Pezo, Armando
name: George, Jean-Marie
name: Jaffrès, Henri
Publisher: name: arXiv
Year: 2024
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Topological insulators are quantum materials involving Time-reversal protected surface states(TSS) making them appealing candidates for the design of next generation of highly efficient spintronic devices. The very recent observation of large transient spin-charge conversion (SCC) and subsequent powerful THz emission from Co|Bi_{1-x}Sb_x bilayers clearly demonstrates such potentiality and feasibility for the near future. Amongst the exotic properties appearing in and at the surface of such quantum materials, spin-momentum locking (SML) and Rashba-Edelstein effects remain as key ingredients to effectively convert the spin degree of freedom into a charge or a voltage signal. In this work, we extend our analyses to the quantification of orbital momentum-locking and related orbital charge conversion effects in Bi_{0.85}Sb_{0.15} via orbital Rashba-Edelstein effects. In that sense, we will provide some clear theoretical and numerical insights implemented by multi-orbital and multi-layered tight-binding methods (TB) to clarify our recent experimental results obtained by THz-TDS spectroscopy.
description: Enhanced text clarifying additional concepts absent in the previous version
Quantum Channel Learning
Creators: name: Belov, Mikhail Gennadievich
name: Dubov, Victor Victorovich
name: Filimonov, Alexey Vladimirovich
name: Malyshkin, Vladislav Gennadievich
Publisher: name: arXiv
Year: 2024
Subjects: subject: Machine Learning (cs.LG)
subject: Numerical Analysis (math.NA)
subject: Quantum Physics (quant-ph)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: The problem of an optimal mapping between Hilbert spaces $IN$ and $OUT$, based on a series of density matrix mapping measurements $ρ^{(l)} \to \varrho^{(l)}$, $l=1\dots M$, is formulated as an optimization problem maximizing the total fidelity $\mathcal{F}=\sum_{l=1}^{M} ω^{(l)} F\left(\varrho^{(l)},\sum_s B_s ρ^{(l)} B^{\dagger}_s\right)$ subject to probability preservation constraints on Kraus operators $B_s$. For $F(\varrho,σ)$ in the form that total fidelity can be represented as a quadratic form with superoperator $\mathcal{F}=\sum_s\left\langle B_s\middle|S\middle| B_s \right\rangle$ (either exactly or as an approximation) an iterative algorithm is developed. The work introduces two important generalizations of unitary learning: 1. $IN$/$OUT$ states are represented as density matrices. 2. The mapping itself is formulated as a mixed unitary quantum channel $A^{OUT}=\sum_s |w_s|^2 \mathcal{U}_s A^{IN} \mathcal{U}_s^{\dagger}$ (no general quantum channel yet). This marks a crucial advancement from the commonly studied unitary mapping of pure states $ϕ_l=\mathcal{U} ψ_l$ to a quantum channel, what allows us to distinguish probabilistic mixture of states and their superposition. An application of the approach is demonstrated on unitary learning of density matrix mapping $\varrho^{(l)}=\mathcal{U} ρ^{(l)} \mathcal{U}^{\dagger}$, in this case a quadratic on $\mathcal{U}$ fidelity can be constructed by considering $\sqrt{ρ^{(l)}} \to \sqrt{\varrho^{(l)}}$ mapping, and on a quantum channel, where quadratic on $B_s$ fidelity is an approximation -- a quantum channel is then obtained as a hierarchy of unitary mappings, a mixed unitary channel. The approach can be applied to studying quantum inverse problems, variational quantum algorithms, quantum tomography, and more.
description: The unitary learning from arXiv:2405.10263 is generalized to density matrices and quantum channels. A Schr\"odinger-like equation is derived for the quantum inverse problem, and a few solutions are presented
Phase-space localization at the lowest Landau level
Creators: name: Craps, Ben
name: De Clerck, Marine
name: Evnin, Oleg
name: Pavlov, Maxim
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We consider bosons with weak contact interactions in a harmonic trap and focus on states at the lowest Landau level. Motivated by the known nontrivial phase-space topography of the energy functional of the corresponding Gross-Pitaevskii equation, we explore Husimi distributions of quantum energy eigenstates in the classical phase space of the Schroedinger field. With interactions turned off, the energy levels are highly degenerate and the Husimi distributions do not manifest any particular localization properties. With interactions turned on, the degeneracy is lifted, and a selection of energy levels emerges whose Husimi distributions are localized around low-dimensional surfaces in the phase space.
description: v2: published version; MATLAB codes available at https://doi.org/10.5281/zenodo.12704876
Axion Window on New Macroscopic Forces
Creators: name: Di Luzio, Luca
name: Gisbert, Hector
name: Nesti, Fabrizio
name: Sørensen, Philip
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Axion-mediated forces are enhanced by the presence of CP-violating axion couplings, which are however tightly constrained by electric dipole moment (EDM) searches. We discuss the underlying hypotheses behind different sources of CP violation at high energies and the interplay between axion-mediated force experiments and EDM observables. Specifically, we identify various mechanisms, based on new sources of CP violation or Peccei-Quinn symmetry breaking, that can significantly relax EDM constraints, leading to a substantial redefinition of the QCD axion window for axion-mediated forces. By considerably enlarging the QCD axion parameter space, our results provide a well-motivated target for experiments probing scalar axion couplings to matter fields. These include fifth-force tests of gravity, as well as searches for spin-dependent forces via precision magnetometry, proton storage rings and ultracold molecules.
description: 8 pages, 1 figure, 1 appendix
Nontrivial solutions for a $(p,q)$-Kirchhoff type system with concave-convex nonlinearities on locally finite graphs
Creators: name: Yu, Zhangyi
name: Xie, Junping
name: Zhang, Xingyong
Publisher: name: arXiv
Year: 2024
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: By using the well-known mountain pass theorem and Ekeland's variational principle, we prove that there exist at least two fully-non-trivial solutions for a $(p,q)$-Kirchhoff elliptic system with the Dirichlet boundary conditions and perturbation terms on a locally weighted and connected finite graph $G=(V,E)$.We also present a necessary condition of the existence of semi-trivial solutions for the system. Moreover, by using Ekeland's variational principle and Clark's Theorem, respectively, we prove that the system has at least one or multiple semi-trivial solutions when the perturbation terms satisfy different assumptions. Finally, we present a nonexistence result of solutions.
Nonlinear Switch and Spatial Lattice Solitons of Photonic s-p Orbitals
Creators: name: Rajeevan, Gayathry
name: Mukherjee, Sebabrata
Publisher: name: arXiv
Year: 2024
Subjects: subject: Optics (physics.optics)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: We develop fs laser-fabricated asymmetric couplers and zig-zag arrays consisting of single and two-mode waveguides with bipartite nonlinearity. The fundamental mode ($s$ orbital) is near resonance with the neighboring higher-order $p$ orbital, causing efficient light transfer at low power. Due to Kerr nonlinearity, the coupler works as an all-optical switch between $s$ and $p$ orbitals. Single- and double-peak spatial solitons of $s$-$p$ orbitals form in the lattice due to the bipartite nature of the on-site nonlinearity. We probe highly localized bulk and edge solitons, peaked at the $s$ and $p$ orbitals, spectrally residing in the photonic band gap. Our work will be important for exploring inter-orbital couplings and nonlinear interactions in intricate photonic devices.
description: 4 pages, 7 figures and supplementary information
Probability-based approach to hybrid classical-quantum systems of any size: Generalized Gleason and Kraus theorems
Creators: name: Camalet, S.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Hybrid classical-quantum systems are of interest in numerous fields, from quantum chemistry to quantum information science. A fully quantum effective description of them is straightforward to formulate when the classical subsystem is discrete. But it is not obvious how to describe them in the general case. We propose a probability-based approach starting with four axioms for hybrid classical-quantum probability measures that readily generalize the usual ones for classical and quantum probability measures. They apply to discrete and non-discrete classical subsystems and to finite and infinite dimensional quantum subsystems. A generalized Gleason theorem that gives the mathematical form of the corresponding hybrid states is shown. This form simplifies when the classical subsystem probabilities are described by a probability density function with respect to a natural reference measure, for example the familiar Lebesgue measure. We formulate a requirement for the transformations, that is, the finite-time evolutions, of hybrid probability measures analogous to the complete positive assumption for quantum operations. For hybrid systems with reference measure, we prove a generalized Kraus theorem that fully determines the considered transformations provided they are continuous with respect to an appropriate metric. Explicit expressions for these transformations are derived when the classical and quantum subsystems are non-interacting, the classical subsystem is discrete, or the Hilbert space of the quantum subsystem is finite-dimensional. We also discuss the quantification of the correlations between the classical and quantum subsystems and a generalization of the quantum operations usually considered in the study of quantum entanglement.
description: Accepted for publication in Physical Review A
Symbolic dynamics of joint brain states during dyadic coordination
Creators: name: Pinto, Italo Ivo Lima Dias
name: Zhou, Zhibin
name: Garcia, Javier O.
name: Srinivasan, Ramesh
Publisher: name: arXiv
Year: 2024
Subjects: subject: Neurons and Cognition (q-bio.NC)
subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: FOS: Biological sciences
subject: FOS: Physical sciences

description: We propose a novel approach to investigate the brain mechanisms that support coordination of behavior between individuals. Brain states in single individuals defined by the patterns of functional connectivity between brain regions are used to create joint symbolic representations of the evolution of brain states in two or more individuals performing a task together. These symbolic dynamics can be analyzed to reveal aspects of the dynamics of joint brain states that are related to coordination or other interactive behaviors. We apply this approach to simultaneous electroencephalographic (EEG) data from pairs of subjects engaged in two different modes of finger-tapping coordination tasks (synchronization and syncopation) under different interaction conditions (Uncoupled, Leader-Follower, and Mutual) to explore the neural mechanisms of multi-person motor coordination. Our results reveal that the dyads exhibit mostly the same joint symbols in different interaction conditions - the most important differences are reflected in the symbolic dynamics. Recurrence analysis shows that interaction influences the dwell time in specific joint symbols and the structure of joint symbol sequences (motif length). In synchronization, increasing feedback promotes stability with longer dwell times and motif length. In syncopation, Leader-Follower interactions enhance stability (increase dwell time and motif length), but Mutual feedback dramatically reduces stability. Network analysis reveals distinct topological changes with task and feedback. In synchronization, stronger coupling stabilizes a few states restricting the pattern of flow between states, preserving a core-periphery structure of the joint brain states. In syncopation, a more distributed flow amongst a larger set of joint brain states reduces the dominance of core joint brain states.
description: 13 pages, 5 figures
Biaxial strain tuning of excitons in monolayer MoSe$_2$ by high-temperature physical vapor deposition
Creators: name: Patel, S.
name: Faltermeier, T.
name: Puri, S.
name: Rodriguez, R.
name: Reynolds, K.
name: Davari, S.
name: Churchill, H. O. H.
name: Borys, N. J.
name: Nakamura, H.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We present strain tuning of excitonic emission in monolayer MoSe$_2$ by using a high-temperature physical vapor deposition (PVD). The use of two amorphous substrates, Si$_{3}$N$_{4}$ and SiO$_{2}$, provides two setpoints to induce distinct amounts of \textit{biaxial} tensile strain determined by a thermal expansion mismatch between the monolayer and the substrate. The tuning rate of the $A$-exciton transition energy is found to be 103 meV/\% by photoluminescence (PL), which represents the highest value realized by biaxial strain in transition metal dichalcogenides. The biaxial nature of the tensile strain is confirmed by polarization-resolved second harmonic generation, which reveals unperturbed in-plane three-fold symmetry of the monolayer. Furthermore, a softening of $A_\mathrm{1g}$ out-of-plane lattice vibration is identified in the Raman spectroscopy, which is known to be insignificant for uniaxial strain. Concomitantly, PL mapping of our PVD monolayers demonstrates (i) larger strain occurs in the interior of the mono-domain islands compared to the edges and (ii) the absence of island-size dependence in the magnitude of induced strain. Our results demonstrate an effective path towards strain engineering of excitons by using growth substrates, which holds great promise as a building block for future optoelectronic applications.
Toward Robust Early Detection of Alzheimer's Disease via an Integrated Multimodal Learning Approach
Creators: name: Chen, Yifei
name: Zhu, Shenghao
name: Fang, Zhaojie
name: Liu, Chang
name: Zou, Binfeng
name: Wang, Yuhe
name: Chang, Shuo
name: Jia, Fan
name: Qin, Feiwei
name: Fan, Jin
name: Peng, Yong
name: Wang, Changmiao
Publisher: name: arXiv
Year: 2024
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Alzheimer's Disease (AD) is a complex neurodegenerative disorder marked by memory loss, executive dysfunction, and personality changes. Early diagnosis is challenging due to subtle symptoms and varied presentations, often leading to misdiagnosis with traditional unimodal diagnostic methods due to their limited scope. This study introduces an advanced multimodal classification model that integrates clinical, cognitive, neuroimaging, and EEG data to enhance diagnostic accuracy. The model incorporates a feature tagger with a tabular data coding architecture and utilizes the TimesBlock module to capture intricate temporal patterns in Electroencephalograms (EEG) data. By employing Cross-modal Attention Aggregation module, the model effectively fuses Magnetic Resonance Imaging (MRI) spatial information with EEG temporal data, significantly improving the distinction between AD, Mild Cognitive Impairment, and Normal Cognition. Simultaneously, we have constructed the first AD classification dataset that includes three modalities: EEG, MRI, and tabular data. Our innovative approach aims to facilitate early diagnosis and intervention, potentially slowing the progression of AD. The source code and our private ADMC dataset are available at https://github.com/JustlfC03/MSTNet.
description: 5 pages, 2 figures
Design of stacked intelligent metasurfaces with reconfigurable amplitude and phase for multiuser downlink beamforming
Creators: name: Darsena, Donatella
name: Verde, Francesco
name: Iudice, Ivan
name: Galdi, Vincenzo
Publisher: name: arXiv
Year: 2024
Subjects: subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: A novel technology based on stacked intelligent metasurfaces (SIM) has recently emerged. This platform involves cascading multiple metasurfaces, each acting as a digitally programmable physical layer within a diffractive neural network. SIM enable the implementation of signal-processing transformations directly in the electromagnetic wave domain, eliminating the need for expensive, high-precision, and power-intensive digital platforms. However, existing studies employing SIM in wireless communication applications rely solely on nearly passive structures that control only the phase of the meta-atoms in each layer. In this study, we propose a SIM-aided downlink multiuser transmission scheme, where the SIM at the base station (BS) end is designed by combining nearly passive layers with phase-only reconfiguration capabilities and active layers integrated with amplifier chips to enable amplitude control. Our optimal design aims at maximizing the sum rate for the best group of users by jointly optimizing the transmit power allocation at the BS and the wave-based beamforming at the SIM. In addition to the standard sum-power constraint at the BS, our optimization framework includes two additional constraints: (i) a per-stream power preserving constraint to prevent propagation losses across the SIM, and (ii) an amplitude constraint to account for power limitations for each active layer. To further reduce the complexity of the optimal beamforming solution, we explore a simple yet suboptimal zero-forcing (ZF) beamforming design, where the wave-based transformation implemented by the SIM is selected to eliminate interference among user streams. Finally, extensive Monte Carlo simulations demonstrate that incorporating both nearly passive and active layers within the SIM significantly enhances capacity compared to previously reported phase-only coding SIM.
description: 21 pages, 13 figures, 1 table, accepted for publication in IEEE Open Journal of Communications Society
Two-field models in the presence of impurities
Creators: name: Bazeia, D.
name: Liao, M. A.
name: Marques, M. A.
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: This work deals with systems of two real scalar fields coupled to impurity functions, meant to model inhomogeneities often encountered in real physical applications. We investigate the theoretical properties of these systems and some of the consequences of impurity doping. We show that the theory may be modified in a way that preserves some BPS sectors, while also greatly impacting the behavior and internal structure of the solution, and exemplify those results with an investigation of a few interesting models in which impurities are coupled to a theory with a quartic potential. It is shown that, in the presence of impurities, the asymptotic behavior of field configurations may be changed, leading to solutions with different long-range properties, which are relevant to several physical applications. Our examples also highlight other important consequences that may follow from the addition of impurities, such as the presence of zero-modes that can significantly change the internal structure of a given solution without altering its energy, the creation of new topological sectors that did not exist in the impurity-free theory, and the possibility of stable, nontrivial configurations generated by topologically trivial boundary conditions. We have also shown that it is sometimes possible to find energy minimizers in BPS sectors which were unpopulated in the canonical theory. These features show that impurities allow for significant flexibility in both the form of energy minimizers and the boundary conditions used to generate them, which may potentially broaden the range of applicability of the theory.
description: 18 pages, 18 figures. Version to appear in Chaos, Solitons and Fractals
D2.3: Guidelines For Handling Ethical, Legal Issues, And Data Protection
Creators: name: Yümlü, Serdar
name: Tosunoğlu, Caner
name: Acar, Ibrahim
name: Demir, Gonca Kara
Publisher: name: Zenodo
Year: 2015

description: The Deliverable D2.3 – STEP Guidelines for Ethical, legal issues and data protection is part of the Work Package 2 Requirements and Analysis. The purpose of this deliverable is to present EU level and national based regulatory frameworks for potential ethical issues that may arise in the conduction of the STEP project. Ethical issues presented in this deliverable have been identified by pilot and technical partners and guidelines for the STEP platform are provided. The intended audience for this deliverable is preliminarily the project partners as the work contained in this document will support the implementation of STEP. However, the research work conducted for the EU regulatory framework on privacy & data protection, national frameworks of pilot countries, ethical analysis of e-Government, cloud and participation based STEP platform will be of interest for a wider audience (e.g. policy makers, researchers, the public).
Reinforcement Learning-based Model Predictive Control for Greenhouse Climate Control
Creators: name: Mallick, Samuel
name: Airaldi, Filippo
name: Dabiri, Azita
name: Sun, Congcong
name: De Schutter, Bart
Publisher: name: arXiv
Year: 2024
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Greenhouse climate control is concerned with maximizing performance in terms of crop yield and resource efficiency. One promising approach is model predictive control (MPC), which leverages a model of the system to optimize the control inputs, while enforcing physical constraints. However, prediction models for greenhouse systems are inherently inaccurate due to the complexity of the real system and the uncertainty in predicted weather profiles. For model-based control approaches such as MPC, this can degrade performance and lead to constraint violations. Existing approaches address uncertainty in the prediction model with robust or stochastic MPC methodology; however, these necessarily reduce crop yield due to conservatism and often bear higher computational loads. In contrast, learning-based control approaches, such as reinforcement learning (RL), can handle uncertainty naturally by leveraging data to improve performance. This work proposes an MPC-based RL control framework to optimize the climate control performance in the presence of prediction uncertainty. The approach employs a parametrized MPC scheme that learns directly from data, in an online fashion, the parametrization of the constraints, prediction model, and optimization cost that minimizes constraint violations and maximizes climate control performance. Simulations show that the approach can learn an MPC controller that significantly outperforms the current state-of-the-art in terms of constraint violations and efficient crop growth.
description: 15 pages, 10 figures, code available at https://github.com/SamuelMallick/mpcrl-greenhouse, accepted for publication in Smart Agricultural Technology
Transformers in Uniform TC$^0$
Creators: name: Chiang, David
Publisher: name: arXiv
Year: 2024
Subjects: subject: Computational Complexity (cs.CC)
subject: Formal Languages and Automata Theory (cs.FL)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Previous work has shown that the languages recognized by average-hard attention transformers (AHATs) and softmax-attention transformers (SMATs) are within the circuit complexity class TC$^0$. However, these results assume limited-precision arithmetic: using floating-point numbers with O(log n) bits (where n is the length of the input string), Strobl showed that AHATs can be approximated in L-uniform TC$^0$, and Merrill and Sabharwal showed that SMATs can be approximated in DLOGTIME-uniform TC$^0$. Here, we improve these results, showing that AHATs with no approximation, SMATs with O(poly(n)) bits of floating-point precision, and SMATs with at most $2^{-O(poly(n))}$ absolute error are all in DLOGTIME-uniform TC$^0$.
Pair size and quantum geometry in a multiband Hubbard model
Creators: name: Iskin, M.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study the size of two-body bound states and Cooper pairs within a multiband Hubbard model that features time-reversal symmetry and uniform pairing on a generic lattice. Our analysis involves (i) an exact calculation of the localization tensor to determine the size of lowest-lying two-body bound state in vacuum, and (ii) an evaluation of the analogous tensor to estimate the average size of Cooper pairs within the mean-field BCS-BEC crossover theory at zero temperature. Beyond the conventional intraband contribution that depends on Bloch bands, we show that pair size also has a geometric contribution governed by the quantum-metric tensor of the Bloch states and their band-resolved quantum-metric tensors. As a concrete example, we investigate the pyrochlore-Hubbard model numerically and demonstrate that, while the pair size diverges in the weakly interacting BCS regime of dispersive bands, it remains finite and relatively small in the flat-band regime, even for infinitesimal interaction, perfectly matching the exact two-body result in the dilute limit.
description: 8 pages with 3 figures; to appear in PRB