cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
On the possibility of a novel (A)dS/CFT relationship emerging in Asymptotic Safety
Creators: name: Ferrero, Renata
name: Reuter, Martin
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Quantum Einstein Gravity (QEG), nonperturbatively renormalized by means of a certain asymptotically safe renormalization group (RG) trajectory, is explored by solving its scale dependent effective field equations and embedding the family of emerging 4-dimensional spacetimes into a single 5-dimensional manifold, which thus encodes the complete information about all scales. By construction the latter manifold is furnished with a natural foliation. Heuristically, its leaves are interpreted as physical spacetime observed on different scales of the experimental resolution. Generalizing earlier work on the embedding of $d$-dimensional Euclidean QEG spacetimes in $(d + 1)$-dimensional flat or Ricci flat manifolds, we admit Lorentzian signature in this paper and we consider embeddings in arbitrary $(d + 1)$-dimensional Einstein spaces. Special attention is paid to the sector of maximally symmetric metrics, and the fundamental definition of QEG in $d = 4$ that employs the cross-over trajectory connecting the non-Gaussian to the Gaussian RG fixed point. Concerning the embedding of the resulting family of 4D de Sitter solutions with a running Hubble parameter, we find that there are only two possible 5D spacetimes, namely the anti-de Sitter manifold AdS$_5$ and the de Sitter manifold dS$_5$. To arrive at this result essential use is made of the monotone scale dependence of the running cosmological constant featured by the gravitational effective average action. We show that if the scale invariance of the QEG fixed points extends to full conformal invariance, the 5D picture of the resulting geometric and field theoretic structure displays a novel kind of "AdS/CFT correspondence". While strongly reminiscent of the usual string theory-based AdS/CFT correspondence, also clear differences are found.
description: 47 pages, 10 figures; further remarks and explanations added, title changed
The evolution of the disc variability along the hard state of the black hole transient GX 339-4
Creators: name: De Marco, B.
name: Ponti, G.
name: Muñoz-Darias, T.
name: Nandra, K.
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We report on the analysis of hard-state power spectral density function (PSD) of GX 339-4 down to the soft X-ray band, where the disc significantly contributes to the total emission. At any luminosity probed, the disc in the hard state is intrinsically more variable than in the soft state. However, the fast decrease of disc variability as a function of luminosity, combined with the increase of disc intensity, causes a net drop of fractional variability at high luminosities and low energies, which reminds the well-known behaviour of disc-dominated energy bands in the soft state. The peak-frequency of the high-frequency Lorentzian (likely corresponding to the high-frequency break seen in active galactic nuclei, AGN) scales with luminosity, but we do not find evidence for a linear scaling. In addition, we observe that this characteristic frequency is energy-dependent. We find that the normalization of the PSD at the peak of the high-frequency Lorentzian decreases with luminosity at all energies, though in the soft band this trend is steeper. Together with the frequency shift, this yields quasi-constant high frequency (5-20 Hz) fractional rms at high energies, with less than 10 percent scatter. This reinforces previous claims suggesting that the high frequency PSD solely scales with BH mass. On the other hand, this constancy breaks down in the soft band (where the scatter increases to ~30 percent). This is a consequence of the additional contribution from the disc component, and resembles the behaviour of optical variability in AGN.
description: 12 pages, 8 figures, accepted for publication in MNRAS
Leading edge vortex formation and wake trajectory: Synthesizing measurements, analysis, and machine learning
Creators: name: Lee, Howon
name: Simone, Nicholas
name: Su, Yunxing
name: Zhu, Yuanhang
name: Ribeiro, Bernardo Luiz R.
name: Franck, Jennifer A.
name: Breuer, Kenneth
Publisher: name: arXiv
Year: 2022
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: The strength and trajectory of a leading edge vortex (LEV) formed by a pitching-heaving hydrofoil (chord $c$) is studied. The LEV is identified using the $Q$-criterion method, which is calculated from the 2D velocity field obtained from PIV measurements. The relative angle of attack at mid-stroke, ${α_{T/4}} $, proves to be an effective method of combining heave amplitude ($h_0/c$), pitch amplitude ($θ_0$), and reduced frequency ($f^*$) into a single variable that predicts the maximum value of $Q$ over a wide range of operating conditions. Once the LEV separates from the foil, it travels downstream and rapidly weakens and diffuses. The downstream trajectory of the LEV has two characteristic shapes. At low values of ${α_{T/4}}$, it travels straight downstream after separating from the foil, while at higher values of ${α_{T/4}} $, an accompanying Trailing Edge Vortex (TEV) forms and the induced velocity generates a cross-stream component to the vortex trajectories. This behavior is accurately predicted using a potential flow model for the LEV and TEV. Supervised machine learning algorithms, namely Support Vector Regression and Gaussian Process Regression, are used to create regression models that predicts the vortex strength, shape and trajectory during growth and after separation. The regression model successfully captures the features of two vortex regimes observed at different values of ${α_{T/4}} $. However, the predicted LEV trajectories are somewhat smoother than observed in the experiments. The strengths of the vortex is often under-predicted. Both of these shortcomings may be attributed to the relatively small size of the training data set.
Apriority, Super-Rigidity, and Fregean Content
Creators: name: Smithson, Robert
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2012

description: What is the difference between an utterance of the sentence Hesperus is Hesperus and an utterance of the sentence Hesperus is Phosphorus? David Chalmers claims that these sentences are psychologically and epistemologically distinct because they are associated with distinct fine-grained Fregean propositions. In The Nature of Epistemic Space, Chalmers offers a rigorous analysis of epistemic possibility that he claims can be used to ground an account of Fregean content that is available to a wide variety of theorists. In this thesis, I will identify the assumptions required by Chalmers' construction of epistemic space in order to evaluate whether it is indeed capable of grounding a widely acceptable account of Fregean content. I conclude the thesis by comparing Chalmers' Fregean content to alternative Russellian accounts of cognitive significance.
Selected Topics of Social Physics: Nonequilibrium Systems
Creators: name: Yukalov, V. I.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: Biological Physics (physics.bio-ph)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Biological sciences
subject: FOS: Physical sciences

description: This review article is the second part of the project ``Selected Topics of Social Physics". The first part has been devoted to equilibrium systems. The present part considers nonequilibrium systems. The style of the paper combines the features of a tutorial and a review, which, from one side, makes it easy to read for nonspecialists aiming at grasping the basics of social physics, and from the other side, describes several rather recent original models containing new ideas that could be of interest to experienced researchers in the field. The present material is based on the lectures that the author had been giving during several years at the Swiss Federal Institute of Technology in Zurich (ETH Zurich).
description: Review, 60 pages
The Structure of Energy Fluxes in Wave Turbulence
Creators: name: Dematteis, Giovanni
name: Lvov, Yuri V.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Chaotic Dynamics (nlin.CD)
subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: FOS: Physical sciences

description: We calculate the net energy per unit time exchanged between two sets of modes in a generic system governed by a three-wave kinetic equation. Our calculation is based on the property of detailed energy conservation of the triadic resonant interactions. In a first application to isotropic systems, we rederive the standard formula for the energy flux as a particular case for adjacent sets. We then exploit the new formalism to quantify the level of locality of the energy transfers in the example of surface capillary waves. A second application to anisotropic wave systems expands the currently available set of tools to investigate magnitude and direction of the energy fluxes in these systems. We illustrate the use of the formalism by characterizing the energy pathways in the oceanic internal wavefield. Our proposed approach, unlike traditional approaches, is not limited to stationarity, scale-invariance and strict locality. In addition, we define a number $w$ that quantifies the scale separation necessary for two sets of modes to be energetically disconnected, with potential consequences in the interpretation of wave-turbulence experiments. The methodology presented here provides a general, simple and systematic approach to energy fluxes in wave turbulence.
Generation of long-lived $W$ states via reservoir engineering in dissipatively coupled systems
Creators: name: Zhang, Guo-Qiang
name: Feng, Wei
name: Xiong, Wei
name: Su, Qi-Ping
name: Yang, Chui-Ping
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Very recently, dissipative coupling was discovered, which develops and broadens methods for controlling and utilizing light-matter interactions. Here, we propose a scheme to generate the tripartite $W$ state in a dissipatively coupled system, where one qubit and two resonators simultaneously interact with a common reservoir. With appropriate parameters, we find the $W$ state is a dark state of the system. By driving the qubit, the dissipatively coupled system will evolve from the ground state to the tripartite $W$ state. Because the initial state is the ground state of the system and no measurement is required, our scheme is easy to implement in experiments. Moreover, the $W$ state decouples from the common reservoir and thus has a very long lifetime. This scheme is applicable to a wide class of dissipatively coupled systems, and we specifically illustrate how to prepare the $W$ state in a hybrid qubit-photon-magnon system by using this scheme.
description: 10 pages, 5 figures
The impact of non-nutritive sucking habits of the risk for sleep disordered breathing in children
Creators: name: Al-Talib, Tanya
Publisher: name: University of North Carolina at Chapel Hill Graduate School
Year: 2015
Subjects: subject: Neurosciences
subject: FOS: Clinical medicine
subject: Dentistry

description: Objective: Sleep disordered breathing (SDB) is prevalent in children and commonly managed with tonsillectomy and adenoidectomy. The aim of the study was to investigate the relationship between non-nutritive sucking (NNS) habits and the risk of SDB in children. Materials and methods: A convenience sample of 84 children 4-12 years of age was recruited for this study. Subjects were categorized as high risk and low risk for SDB based on the Pediatric Sleep Questionnaire (PSQ). The presence or absence of NNS was determined using a customized habit questionnaire. Results: Relative to NNS, there was no statistically significant difference between children in the low risk and high risk groups for SDB (p=0.2), while the risk for SDB between breast fed (BF) and bottle fed children was significantly different (p<0.001). Conclusion: NNS did not reduce the risk for SDB in the study groups, but breastfeeding dramatically reduced the risk.
Emergence of polarization in coevolving networks
Creators: name: Liu, Jiazhen
name: Huang, Shengda
name: Aden, Nathan
name: Johnson, Neil
name: Song, Chaoming
Publisher: name: arXiv
Year: 2022
Subjects: subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: Polarization is a ubiquitous phenomenon in social systems. Empirical studies document substantial evidence for opinion polarization across social media, showing a typical bipolarized pattern devising individuals into two groups with opposite opinions. While coevolving network models have been proposed to understand polarization, existing works cannot generate a stable bipolarized structure. Moreover, a quantitative and comprehensive theoretical framework capturing generic mechanisms governing polarization remains unaddressed. In this paper, we discover a universal scaling law for opinion distributions, characterized by a set of scaling exponents. These exponents classify social systems into bipolarized and depolarized phases. We find two generic mechanisms governing the polarization dynamics and propose a coevolving framework that counts for opinion dynamics and network evolution simultaneously. Under a few generic assumptions on social interactions, we find a stable bipolarized community structure emerges naturally from the coevolving dynamics. Our theory analytically predicts two-phase transitions across three different polarization phases in line with the empirical observations for the Facebook and blogosphere datasets. Our theory not only accounts for the empirically observed scaling laws but also allows us to predict scaling exponents quantitatively.
Introducing Non-Linear Activations into Quantum Generative Models
Creators: name: Gili, Kaitlin
name: Sveistrys, Mykolas
name: Ballance, Chris
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Machine Learning (cs.LG)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Due to the linearity of quantum mechanics, it remains a challenge to design quantum generative machine learning models that embed non-linear activations into the evolution of the statevector. However, some of the most successful classical generative models, such as those based on neural networks, involve highly non-linear dynamics for quality training. In this paper, we explore the effect of these dynamics in quantum generative modeling by introducing a model that adds non-linear activations via a neural network structure onto the standard Born Machine framework - the Quantum Neuron Born Machine (QNBM). To achieve this, we utilize a previously introduced Quantum Neuron subroutine, which is a repeat-until-success circuit with mid-circuit measurements and classical control. After introducing the QNBM, we investigate how its performance depends on network size, by training a 3-layer QNBM with 4 output neurons and various input and hidden layer sizes. We then compare our non-linear QNBM to the linear Quantum Circuit Born Machine (QCBM). We allocate similar time and memory resources to each model, such that the only major difference is the qubit overhead required by the QNBM. With gradient-based training, we show that while both models can easily learn a trivial uniform probability distribution, on a more challenging class of distributions, the QNBM achieves an almost 3x smaller error rate than a QCBM with a similar number of tunable parameters. We therefore provide evidence that suggests that non-linearity is a useful resource in quantum generative models, and we put forth the QNBM as a new model with good generative performance and potential for quantum advantage.
Understanding the relationship between type 2 diabetes and depression: lessons from genetically informative study designs
Creators: name: Bergmans, R. S.
name: Rapp, A.
name: Kelly, K. M.
name: Weiss, D.
name: Mezuk, Briana
Publisher: name: Wiley Periodicals, Inc.
Year: 2021
Subjects: subject: Medicine (General)
subject: Health Sciences

description: AimsTo conduct a systematic review in order to comprehensively synthesize the findings from a diverse range of genetically informative studies on comorbid depression and type 2 diabetes.MethodsDatabase searches (1 January 2008 to 1 June 2020) in PubMed and EMBASE were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta‐analyses (PRISMA) guidelines. Eligible reports employed any type of genetically informed design, including twin modelling, Mendelian randomization, genome‐wide association studies, polygenetic risk scores, or linkage disequilibrium score regression. Searches generated 451 unique citations, and 16 manuscripts met the inclusion criteria.ResultsThe included studies addressed three aetiological models of the depression–diabetes relationship: uni‐ or bi‐directional phenotypic causation; shared genetic liability; or gene–environment interaction. From these studies, there is modest evidence that type 2 diabetes is causally related to risk of developing depression, but much more limited evidence that depression is causally related to risk of diabetes. There is little evidence of shared genetic liability between depression and diabetes or of gene–environment interaction.ConclusionsFindings from genetically informed studies are mixed but provide some support for the uni‐ or bi‐directional phenotypic model of depression and type 2 diabetes. Future studies should also explore the hypothesis that this relationship may be influenced by shared environmental risk factors. Findings can inform multifaceted approaches to diabetes prevention and care that reflect how psychosocial factors contribute to type 2 diabetes risk and outcomes.
Black Hole Field Theory with a Firewall in two spacetime dimensions
Creators: name: Ho, C. T. Marco
name: Su, Daiqin
name: Mann, Robert B.
name: Ralph, Timothy C.
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose that the vacuum state of a scalar field around a black hole is a modified Unruh vacuum. In (1+1) dimensions, we show that a free-faller close to such an horizon can be modelled as an inertial observer in a modified Minkowski vacuum. The modification allows for information-leaking correlations at high frequencies. Using a Gaussian detector centred at $k_0$, we find that the expectation value of the number operator for a detector crossing the horizon is proportional to $1/|k_0|$, implying that the free-faller will observe unbounded numbers of high energy photons, i.e. a firewall.
description: 6 pages, 3 figures
Housekeeping and excess entropy production for general nonlinear dynamics
Creators: name: Yoshimura, Kohei
name: Kolchinsky, Artemy
name: Dechant, Andreas
name: Ito, Sosuke
Publisher: name: arXiv
Year: 2022
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Functional Analysis (math.FA)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We propose a housekeeping/excess decomposition of entropy production for general nonlinear dynamics in a discrete space, including chemical reaction networks and discrete stochastic systems. We exploit the geometric structure of thermodynamic forces to define the decomposition; this does not rely on the notion of a steady state, and even applies to systems that exhibit multistability, limit cycles, and chaos. In the decomposition, distinct aspects of the dynamics contribute separately to entropy production: the housekeeping part stems from a cyclic mode that arises from external driving, generalizing Schnakenberg's cyclic decomposition to non-steady states, while the excess part stems from an instantaneous relaxation mode that arises from conservative forces. Our decomposition refines previously known thermodynamic uncertainty relations and speed limits. In particular, it not only improves an optimal-transport-theoretic speed limit, but also extends the optimal transport theory of discrete systems to nonlinear and nonconservative settings.
description: 27 pages, 7 figures
Womanist performative pedagogy
Creators: name: Hardy, Kimberly Annette
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2009

description: For African American young women of color, the experiences in education rarely address how race and gender specifically intersect as a cultural way of knowing. The purpose of this work is to theorize Womanist Performative Pedagogy in an attempt to answer the call for pedagogies that specifically engage to the experiences of adolescent women of color in the classroom. Womanist Performative Pedagogy, grounded in the social change theory of womanism, as an anti-oppressive, vernacular, communitarian, and spiritual way of teaching, which seeks to create sacred spaces for the purpose of integrating the body, mind, and spirit towards the humanization of students, teachers, and communities in the process of education. This pedagogy engages the performative to enact womanist caring through exhibiting an ethic of care that embraces the maternal, acts with political clarity, and engages an ethic of risk.
Geometrical frustration versus Kitaev interactions in BaCo$_2$(AsO$_4$)$_2$
Creators: name: Halloran, Thomas
name: Desrochers, Félix
name: Zhang, Emily Z.
name: Chen, Tong
name: Chern, Li Ern
name: Xu, Zhijun
name: Winn, Barry
name: Graves-Brook, M. K.
name: Stone, M. B.
name: Kolesnikov, Alexander I.
name: Qui, Yiming
name: Zhong, Ruidan
name: Cava, Robert
name: Kim, Yong Baek
name: Broholm, Collin
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Recently, Co-based honeycomb magnets have been proposed as promising candidate materials to host the Kitaev spin liquid state. One of the front-runners is BaCo$_2$(AsO$_4$)$_2$ (BCAO), where it was suggested that the exchange processes between Co$^{2+}$ ions via the surrounding edge-sharing oxygen octahedra could give rise to bond-dependent Kitaev interactions. In this work, we present and analyze comprehensive inelastic neutron scattering studies of BCAO with fields in the honeycomb plane. Combining the constraints from the magnon excitations in the high-field polarized state and the inelastic spin structure factor measured in zero magnetic field, we examine two leading theoretical models: the Kitaev-type \JKG model and the \XXZ model. We show that the existing experimental data can be consistently accounted for by the \XXZ model but not by the \JKG model, and we discuss the implications of these results for the realization of a spin liquid phase in BCAO and more generally for the realization of the Kitaev model in cobaltates.
description: 15 pages, 10 figures
Surface valence transition in SmS by alkali metal adsorption
Creators: name: Nakamura, Takuto
name: Nakaya, Toru
name: Ohtsubo, Yoshiyuki
name: Sugihara, Hiroki
name: Tanaka, Kiyohisa
name: Yukawa, Ryu
name: Kitamura, Miho
name: Kumigashira, Hiroshi
name: Imura, Keiichiro
name: Suzuki, Hiroyuki S.
name: Sato, Noriaki K.
name: Kimura, Shin-ichi
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The electronic structure changes of SmS surfaces under potassium (K) doping are elucidated using synchrotron-based core-level photoelectron spectroscopy and angle-resolved photoelectron spectroscopy (ARPES). The Sm core-level and ARPES spectra indicate that the Sm mean valence of the surface increased from the nearly divalent to trivalent states, with increasing K deposition. Carrier-induced valence transition (CIVT) from Sm$^{2+}$ to Sm$^{3+}$ exhibits a behavior opposite to that under conventional electron doping. Excess electrons are trapped by isolated excitons, which is inconsistent with the phase transition from the black insulator with Sm$^{2+}$ to the gold metal with Sm$^{3+}$ under pressure. This CIVT helps to clarify the pressure-induced black-to-golden phase transition in this material, which originates from the Mott transition of excitons.
description: 7 pages, 6 figures
Policies and procedures: an analysis of the UNC Ram's Clubs decision making process
Creators: name: Mock, Che Becori Ptolemy
Publisher: name: University of North Carolina at Chapel Hill
Year: 2010

description: This study examined whether the UNC Rams Club incorporates strategic management principles when implementing policies and procedures. Data was collected for this study from archived records, online materials, and in person interviews with Directors of the UNC Rams Club. A set number of uniform planning questions were posed to each subject, each participant was asked to answer the questions relative to the operation of the organization as a whole. The researcher conducted a careful analysis of the participants' responses to the interview questions. The research concluded that the UNC Rams Club's process for changing policies and procedures is inconsistent with strategic management theory. The application and use of the findings were discussed. Research concludes with how to incorporate strategic management principles. A policies and procedures fundraising manual template which details how policies and procedures can be organized for UNC Rams Club is suggested at the end of the study.
ADM mass in warp drive spacetimes
Creators: name: Schuster, Sebastian
name: Santiago, Jessica
name: Visser, Matt
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: What happens when a warp bubble has mass? This seemingly innocent question forces one to carefully formalize exactly what one means by a warp bubble, exactly what one means by having the warp bubble "move" with respect to the fixed stars, and forces one to more carefully examine the notion of mass in warp-drive spacetimes. This is the goal of the present article. In this process, we will see that often-made throw-away comments regarding "payloads" are even simpler than commonly assumed, while there are two further, distinct yet subtle ways in which a mass can appear in connection with a warp drive space-time: One, that the warp bubble (not its payload) has the mass; two, that the mass is a background feature in front of which the warp drive moves. For simplicity, we consider generic Natário warp drives with zero-vorticity flow field. The resulting spacetimes are sufficiently simple to allow an exact and fully explicit computation of all of the stress-energy components, and verify that (as expected) the null energy condition (NEC) is violated. Likewise the weak, strong, and dominant energy conditions (WEC, SEC, DEC) are violated. Indeed, this confirms the community's folk wisdom, and recent (fully general, but implicit) results of the present authors which closed previous gaps in the argument. However, folk wisdom should be carefully and critically examined before being believed, and the present examples for general results will greatly aid physical intuition.
description: V1:19 pages; V2: 22 pages. Authors re-ordered, abstract rewritten; 4 references added; improved presentation and discussion; calculations unaltered; physics conclusions unaltered
Resummation and cancellation of the VIA source in electroweak baryogenesis
Creators: name: Postma, Marieke
name: van de Vis, Jorinde
name: White, Graham
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We re-derive the vev-insertion approximation (VIA) source in electroweak baryogenesis. In contrast to the original derivation, we rely solely on 1-particle-irreducible self-energy diagrams. We solve the Green's function equations both perturbatively and resummed over all vev-insertions. The VIA source corresponds to the leading order contribution in the gradient expansion of the Kadanoff-Baym (KB) equations. We find that it vanishes both for bosons and fermions, both in the perturbative and in the resummed approach. Interestingly, the non-existence of the source is a result of a cancellation between different terms in the KB equations, and not of a pathology in the vev-insertion approximation itself.
description: 29 Pages
No contextual advantage in non-paradoxical scenarios of two state vector formalism
Creators: name: Singh, Jaskaran
name: Bhati, Rajendra Singh
name: Arvind
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The two state vector formalism (TSVF) was proposed by Aharonov, Bergmann, and Lebowitz (ABL) to provide a way for the counterfactual assignment of the probabilities of outcomes of contemplated but unperformed measurements on quantum systems. This formalism underlies various aspects of foundations of quantum theory and has been used significantly in the development of weak values and several proofs of quantum contextuality. We consider the application of TSVF, with pre- and post-selection (PPS) and the corresponding ABL rule, as a means to unearth quantum contextuality. We use the principle of exclusivity to classify the resultant pre- and post-selection scenarios as either paradoxical or non-paradoxical. In light of this, we find that several previous proofs of the emergence of contextuality in PPS scenarios are only possible if the principle of exclusivity is violated and are therefore classified as paradoxical. We argue that these do not constitute a proper test of contextuality. Furthermore, we provide a numerical analysis for the KCBS scenario as applied in the paradigm of TSVF and find that non-paradoxical scenarios do not offer any contextual advantage. Our approach can be easily generalized for other contextual scenarios as well.
description: Comments are welcome
Force-detected Magnetic Resonance Imaging of Influenza Viruses in the Overcoupled Sensor Regime
Creators: name: Krass, Marc-Dominik
name: Prumbaum, Nils
name: Pachlatko, Raphael
name: Grob, Urs
name: Takahashi, Hiroki
name: Yamauchi, Yohei
name: Degen, Christian L.
name: Eichler, Alexander
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: Long and thin scanning force cantilevers are sensitive to small forces, but also vulnerable to detrimental non-contact interactions. Here we present an experiment with a cantilever whose spring constant and static deflection are dominated by the interaction between the tip and the surface, a regime that we refer to as ``overcoupled''. The interactions are an obstacle for ultrasensitive measurements like nanoscale magnetic resonance imaging (nanoMRI). We discuss several strategies to overcome the challenges presented by the overcoupling, and demonstrate proton nanoMRI measurements of individual influenza virus particles.
description: 9 pages, 9 figures
Disk storage management for LHCb based on Data Popularity estimator
Creators: name: Hushchyn, Mikhail
name: Charpentier, Philippe
name: Ustyuzhanin, Andrey
Publisher: name: arXiv
Year: 2015
Subjects: subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: Machine Learning (cs.LG)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: This paper presents an algorithm providing recommendations for optimizing the LHCb data storage. The LHCb data storage system is a hybrid system. All datasets are kept as archives on magnetic tapes. The most popular datasets are kept on disks. The algorithm takes the dataset usage history and metadata (size, type, configuration etc.) to generate a recommendation report. This article presents how we use machine learning algorithms to predict future data popularity. Using these predictions it is possible to estimate which datasets should be removed from disk. We use regression algorithms and time series analysis to find the optimal number of replicas for datasets that are kept on disk. Based on the data popularity and the number of replicas optimization, the algorithm minimizes a loss function to find the optimal data distribution. The loss function represents all requirements for data distribution in the data storage system. We demonstrate how our algorithm helps to save disk space and to reduce waiting times for jobs using this data.
Fuel Residence Times for Clean Combustion of Coal in a Pressurized Fluidized Bed - Cold Flow Study
Creators: name: Séguin, Marc-André
Publisher: name: Université d'Ottawa / University of Ottawa
Year: 2017
Subjects: Fluidized bed
Residence time
Tube Bank
Pressure
Entrainment
Fines

description: Anthropogenic Climate Change is amongst the greatest challenges of human civilization. A key area that will play a large role in mitigating its effects are clean fossil fuel applications. Clean coal combustion is one such application with an urgent timeline. This can be achieved with an oxygen-fired pressurized fluidized bed combustor with downstream carbon capture and sequestration. In relation to pressurized fluidization processes, understanding the influence of pressure on bed hydrodynamics and in turn their effect on parameters including fuel residence time is essential. For the proposed combustor, the heat exchanger boiler tubes are submerged in the fluidized bed such that the effect of a horizontal tube bank on the fuel residence time is also of great importance. The main focus of present work was to evaluate the impact of gas velocity, pressure, presence of a tube bank and fuel feed rate on the average fuel residence time. Experiments were conducted under cold flow conditions in a pilot-scale pressurized fluidized bed with an inner diameter of 0.15 m. The fluidization material was relatively large glass beads (1.0 mm in diameter) while the fuel particles were simulated with smaller glass beads (40 to 138 μm in diameter), susceptible to entrainment. Operating pressures and superficial gas velocities tested were between 101.3 and 1200 kPa and 0.4 and 1.1 m/s respectively. To simulate coal combustors, experiments were then conducted in a continuous mode where the fuel particles were continuously fed to the fluidized bed of large particles over a desired period of time. Downstream, entrained particles were continuously captured to determine the entrainment rate and mass of fuel particles inside the fluidized bed at steady state, which yielded the average fuel residence time. The combination of elevated pressure with the tube bank present was found to enhance gas bubble break up and reduce the average gas bubble size. In turn, this increased the average fuel residence time of 83 μm particles by nearly 3 fold to a value of 77 s in comparison to 27 s at atmospheric pressure. The effect of gas velocity was not found to be statistically significant under the range tested. Similarly the effect of increased fuel feed rate by 50% neither had a statistically significant impact.
Quantum oscillation and wave packet revival in conical graphene structure
Creators: name: Sinha, Debabrata
name: Berche, Bertrand
Publisher: name: arXiv
Year: 2015
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We present analytical expressions for the eigenstates and eigenvalues of electrons confined in a graphene monolayer in the presence of a disclination. The calculations are performed in the continuum limit approximation in the vicinity of the Dirac points, solving Dirac equation by freezing out the carrier radial motion. We include the effect of an external magnetic field and show the appearence of Aharonov-Bohm oscillation and find out the conditions of gapped and gapless states in the spectrum. We show that the gauge field due to a disclination lifts the orbital degeneracy originating from the existence of two valleys. The broken valley degeneracy has a clear signature on quantum oscillations and wave packet dynamics.
Média et crises politiques : Le rôle professionnel des journalistes de la RTI (Radiotélévision ivoirienne) dans la crise post-électorale de 2010 en Côte d’Ivoire
Creators: name: Kako, Denise
Publisher: name: Université d'Ottawa / University of Ottawa
Year: 2017
Subjects: Rôle professionnel
Piliers normatifs
Journalisme de crise
Conflits armés
Contexte
Côte d’Ivoire

description: La présente recherche se penche sur le rôle professionnel des journalistes de la RTI (Radiotélévision ivoirienne) dans la crise post-électorale de 2010 en Côte d’Ivoire. En effet, à la fin des élections présidentielles du 28 novembre 2010, la Côte d’Ivoire s’est vue plongée dans une crise sans précédent. Cette crise, connue sous l’appellation de « crise postélectorale », a eu pour élément déclencheur la proclamation des résultats, par le président de la Commission électorale indépendante (CEI) Youssouf Bakayoko, le 2 décembre 2010 qui donnaient Alassane Dramane Ouattara vainqueur avec 54,10 % des voix, contre 45,90 % pour Laurent Gbagbo avec un taux de participation de 81,1%. Ces résultats seront invalidés et inversés le lendemain par le président du Conseil Constitutionnel Paul Yao N'Dré, qui a crédité Laurent Gbagbo de 51,45 % contre 48,55 % pour Ouattara. Dès lors, le pays s’est retrouvé avec deux présidents. Tandis que les militants se sont mis à revendiquer la victoire de part et d’autre, nous assistions à la création, par les partisans d’Alassane Dramane Ouattara, d’une chaine de télévision dénommée TCI (Télévision Côte d’Ivoire). Dès lors, certains journalistes ont fait le choix d’aller servir à la TCI ou de demeurer en poste à la RTI (Radiotélévision ivoirienne). À travers cette migration d’une télévision à une autre, nous nous demandons quels rôles professionnels les journalistes de la RTI ont-ils joué exactement dans cette crise? Pour répondre à cette question, nous avons choisi comme cadre référentiel les conclusions des travaux de Mellado et de Lagos dans lesquels ont été répertorié six rôles du journalisme que sont : l’interventionnisme, le chien de garde, le loyalisme, le journalisme de proximité, le sensationnalisme et le civisme (Mellado et Lagos, 2014). Pour mener à bien cette recherche, nous avons opté pour la méthode qualitative avec comme technique de collecte de données l’entrevue semi-dirigée. Cette technique nous a permis de rencontrer et interviewer des journalistes, témoins privilégiés et acteurs compétents de ce mouvement migratoire entre la RTI et la TCI. Ceci en vue d’appréhender leurs sentiments, leurs opinions, leurs motivations, leurs expériences d’une part et d’autre part de mieux cibler leurs rôles pendant la crise.
Sharpening the Distance Conjecture in Diverse Dimensions
Creators: name: Etheredge, Muldrow
name: Heidenreich, Ben
name: Kaya, Sami
name: Qiu, Yue
name: Rudelius, Tom
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The Distance Conjecture holds that any infinite-distance limit in the scalar field moduli space of a consistent theory of quantum gravity must be accompanied by a tower of light particles whose masses scale exponentially with proper field distance $\Vertϕ\Vert$ as $m \sim \exp(- λ\Vertϕ\Vert)$, where $λ$ is order-one in Planck units. While the evidence for this conjecture is formidable, there is at present no consensus on which values of $λ$ are allowed. In this paper, we propose a sharp lower bound for the lightest tower in a given infinite-distance limit in $d$ dimensions: $λ\geq 1/\sqrt{d-2}$. In support of this proposal, we show that (1) it is exactly preserved under dimensional reduction, (2) it is saturated in many examples of string/M-theory compactifications, including maximal supergravity in $d= \text{4 - 10}$ dimensions, and (3) it is saturated in many examples of minimal supergravity in $d= \text{4 - 10}$ dimensions, assuming appropriate versions of the Weak Gravity Conjecture. We argue that towers with $λ< 1/\sqrt{d-2}$ discussed previously in the literature are always accompanied by even lighter towers with $λ\geq 1/\sqrt{d-2}$, thereby satisfying our proposed bound. We discuss connections with and implications for the Emergent String Conjecture, the Scalar Weak Gravity Conjecture, the Repulsive Force Conjecture, large-field inflation, and scalar field potentials in quantum gravity. In particular, we argue that if our proposed bound applies beyond massless moduli spaces to scalar fields with potentials, then accelerated cosmological expansion cannot occur in asymptotic regimes of scalar field space in quantum gravity.
description: 83 pages, 6 figures
The Application of Affordance Theory in Understanding Social Media Users' Perception of Algorithms
Creators: name: Kim, Jisu
Publisher: name: Singapore Institute of Technology
Year: 2023
Subjects: Human-computer interaction

description: Social media algorithms have been used by different social media platforms to sort and filter content on their main feeds according to their predetermined rules. Most content that social media users see on platforms is chosen by their algorithms, and thus social media algorithms play a crucial role in structuring our online experience. However, due to the opacity of social media algorithms, our understanding of platforms is limited, and users have different perceptions and attitudes toward algorithmic decision-making on social media. Although a few scholars have examined how social media users make sense of and engage with algorithms based on different concepts and theories, we still do not have a clear concept or theoretical framework to understand how social media users have different perceptions of social media algorithms. Thus, this paper proposes how affordance theory can be applied in understanding user interaction with social media algorithms.
Constraints on Light Leptophilic Dark Matter Mediators from Decay Experiments
Creators: name: Bickendorf, Gerrit
name: Drees, Manuel
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the influence of leptophilic dark matter interactions on decays of muons and ground state mesons in existing experiments. We consider a secluded dark sector exclusively interacting with leptons via either a (leptophilic) scalar or vector mediator. These interactions will therefore influence leptonic decays and deform the energy spectra. We first study the Michel decay of muons, $μ^+\rightarrow e^+ν_e \barν_μ$, which allow us to constrain the parameter space reasonably well. Secondly, the rare $π^\pm$, $K^\pm$, $D^\pm$ and $D_s^\pm$ decays to $eν$ will be considered. Scalar mediators would remove the Standard Model helicity suppression, so that strong constraints can be derived. The resulting bounds on the couplings of the light mediators to electrons and muons still turn out to be somewhat weaker than those from searches at low--energy $e^+e^-$ colliders and the magnetic moment of the muon, respectively. Finally, we show that kaon and pion decays basically exclude a ''Co--SIMP'' scenario where a scalar dark matter particle has a dimension--5 coupling to electrons.
description: 18 pages, 8 figures
Star formation histories of UV-luminous galaxies at $z \simeq 6.8$: implications for stellar mass assembly at early cosmic times
Creators: name: Whitler, Lily
name: Stark, Daniel P.
name: Endsley, Ryan
name: Leja, Joel
name: Charlot, Stéphane
name: Chevallard, Jacopo
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The variety of star formation histories (SFHs) of $z\gtrsim6$ galaxies provides important insights into early star formation, but has been difficult to systematically quantify. Some observations suggest that many $z\sim6-9$ galaxies are dominated by $\gtrsim200$ Myr stellar populations, implying significant star formation at $z\gtrsim9$, while others find that most reionization era galaxies are $\lesssim10$ Myr, consistent with little $z\gtrsim9$ star formation. Here, we quantify the distribution of ages of UV-bright ($-22.5\lesssim M_{UV}\lesssim-21$) galaxies colour-selected to lie at $z\simeq6.6-6.9$, an ideal redshift range to systematically study the SFHs of reionization era galaxies with ground-based observatories and Spitzer. We infer galaxy properties with two SED modelling codes and compare results, finding that stellar masses are largely insensitive to the model, but the inferred ages can vary by an order of magnitude. We infer a distribution of ages assuming a simple, parametric SFH model, finding a median age of $\sim30-70$ Myr depending on SED model. We quantify the fractions of $\leq10$ Myr and $\geq250$ Myr galaxies, finding that these systems comprise $\sim15-30$ percent and $\sim20-25$ percent of the population, respectively. With a flexible SFH model, the shapes of the SFHs are consistent with those implied by the simple model (e.g. young galaxies have rapidly rising SFHs). However, stellar masses can differ significantly, with those of young systems sometimes being more than an order of magnitude larger with the flexible SFH. We quantify the implications of these results for $z\gtrsim9$ stellar mass assembly and discuss improvements expected from JWST.
description: 24 pages, 20 figures, 2 appendices, accepted to MNRAS
Theory of Muon g-2
Creators: name: Malaescu, Bogdan
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The longstanding discrepancy between the measured and the predicted values of the anomalous magnetic moment of the muon, $a_μ= (g-2)/2$, is one of the most intriguing potential hints of new physics in particle physics. After a brief introduction, the status of the theoretical prediction of g-2 is presented, with some focus on the contributions yielding the dominant uncertainties. The status of the comparison with the experimental measurement is then discussed.
description: 7 pages, 5 figures, contribution to the proceedings of the SPIN2021 symposium