cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Design of a computer-assisted speechreading training system for Japanese
Creators: name: Fujiu, Masako
Publisher: name: University of British Columbia
Year: 2010

description: Speechreading is known to play an important role in speech perception, particularly for hearing-impaired individuals. Computer-Aided Speechreading Training (CAST) systems have been implemented for English and French, to train adults with mild-to-moderate hearing loss to improve their communicative ability with an effective use of visual speech information. Recent tests have shown that the CAST system is effective in improving speechreading performance. The purpose of this study is to design a similar system for Japanese, which will be called CAST-J. CAST-J follows the basic principles used for the English and French versions of CAST: (1) it uses the method of discourse tracking, in which training is focused on the perception of ongoing speech; (2) it aims at training subjects to integrate visual information, auditory information, and linguistic redundancy of the message; (3) it is designed for post-lingually hearing-impaired adults. Adults with cochlear implants are also considered as a possible target population for CAST-J, as long as they use auditory information of speech as a primary source in speech perception. The lessons of CAST-J are organized around the concept of viseme. Fifteen visemes of Japanese have been determined for this study, more specifically, five vowel visemes: { i }, { e }, { a }, { o }, and { u }, seven consonant visemes: { p, b, m }, { w, Φ }, { r }, { s, z, t, d, n, ts, dz }, { k, g, h }, { f }, and { j, q, ∫, t∫, d₃, η }, and three haku visemes: { N }, { Q }, and { R }. The four sections of each lesson are designed (1) to review previously taught visemes; (2) to practice the recognition of a new viseme; (3) to practice new and old visemes by the tracking method; and (4) to recap the lesson. The lessons progress from easy-to-recognize visemes to difficult-to-recognize visemes. There are sixteen lessons, and two extra lessons are available for pre-and post-training comparison. The hardware required by CAST-J includes a microcomputer, a video disc player, a high resolution video monitor, and a printer. The system allows the instructor (an audiologist) to select the appropriate speaking rate for the video (fast or slow), whether the trainee will practice with or without audio signal, and to skip if wanted the optional lessons or part of a lesson, depending upon the level of the trainee.
Is a gas of strongly interacting atomic fermions a nearly perfect fluid?
Creators: name: Turlapov, A.
name: Kinast, J.
name: Clancy, B.
name: Luo, Le
name: Joseph, J.
name: Thomas, J. E.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We use all-optical methods to produce a highly-degenerate Fermi gas of spin-1/2 $^6$Li atoms. A magnetic field tunes the gas near a collisional (Feshbach) resonance, producing strong interactions between spin-up and spin-down atoms. This atomic gas is a paradigm for strong interactions in nature, and provides tests of current quantum many-body calculational methods for diverse systems, including very high temperature superconductors, nuclear matter in neutron stars, and the quark-gluon plasma of the Big Bang. We have measured properties of a breathing mode over a wide range of temperatures. At temperatures both below and well above the superfluid transition, the frequency of the mode is nearly constant and very close to the hydrodynamic value. However, explaining both the frequency and the damping rate in the normal collisional regime has not been achieved. Our measurements of the damping rate as a function of the energy of the gas are used to estimate an upper bound on the viscosity. Using our new measurements of the entropy of the gas, we estimate the ratio of the shear viscosity to the entropy density, and compare the result with the lower bound for quantum viscosity recently predicted using string theory methods.
description: 10 pages, 5 figures
Machine Learning Universal Bosonic Functionals
Creators: name: Schmidt, Jonathan
name: Fadel, Matteo
name: Benavides-Riveros, Carlos L.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: The one-body reduced density matrix $γ$ plays a fundamental role in describing and predicting quantum features of bosonic systems, such as Bose-Einstein condensation. The recently proposed reduced density matrix functional theory for bosonic ground states establishes the existence of a universal functional $\mathcal{F}[γ]$ that recovers quantum correlations exactly. Based on a novel decomposition of $γ$, we have developed a method to design reliable approximations for such universal functionals: our results suggest that for translational invariant systems the constrained search approach of functional theories can be transformed into an unconstrained problem through a parametrization of an Euclidian space. This simplification of the search approach allows us to use standard machine-learning methods to perform a quite efficient computation of both $\mathcal{F}[γ]$ and its functional derivative. For the Bose-Hubbard model, we present a comparison between our approach and Quantum Monte Carlo.
description: 13 pages, 6 figures; close to the published version
title: The assessment-related logics of practice at a South West Multi-Academy Trust
Creators: name: Morahan, Samuel Gordon
Publisher: name: University of Plymouth
Year: 2024
Subjects: subject: Assessment
subject: Alternative Provision
subject: Marketisation
subject: Commodification
subject: Other (e.g., MD, EdD, DBA, DClinPsy)

description: Over the last 40 years there have been widescale changes to the British education system. Through the process of neoliberalisation, education has become a commodity to be bought and sold with an ever-increasing emphasis on performativity and its related measures. Within this educational market, alternative provision settings provide commissioning schools with opportunities to purchase placements and packages for pupils, who for a variety of reasons, are unable to engage in mainstream education. Alternative provision settings must evidence value for money to these schools, whilst meeting statutory inspection requirements. Assessment practices and the numerical data they generate are central within this commodified and performative climate. Following the removal of what was considered a flawed national curriculum levels system, schools in England, including the one which forms the site for this research, were tasked with the design and implementation of their own assessment systems. Considering the above, this research addresses the following questions: (1) What are the assessment-related logics of practice at a South West Multi-Academy Trust? (2) How are these logics of practice formed within the educational landscape of commodification? It gains insight from eight professionals in a South West Multi-Academy Trust. The analysis focuses on levels of assessment and an analytics of government to show how assessment logics are formed in the commodified landscape and subsequent impact of performativity on schools, professionals and pupils. The findings highlight the market function of the assessment system whereby the South West Multi-Academy Trust, through metrics, evidences progress and value for money to stakeholders and commissioners. The study highlights a lack of common understanding between staff, pupils and stakeholders and further identifies inconsistencies that exist at the judgement, decision and impact levels of assessment. In drawing conclusions, the research recommends a process of review related to the current assessment system at the South West Multi-Academy Trust and reflects on the need for a holistic model of assessment which puts the pupils at the heart of its existence. This thesis contributes to knowledge within the areas of commodification and marketisation of education and examines the implications for assessment policy and practice in alternative provision.
Another Odd Thing About Unparticle Physics
Creators: name: Georgi, Howard
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The peculiar propagator of scale invariant unparticles has phases that produce unusual patterns of interference with standard model processes. We illustrate some of these effects in $e^+e^-\toμ^+μ^-$.
description: 9 pages, 8 figures - minor wording changes and additional reference in v2
Electric-field-induced displacement of a charged spherical colloid embedded in an elastic Brinkman medium
Creators: name: Hill, Reghan J.
name: Ostoja-Starzewski, Martin
Publisher: name: arXiv
Year: 2007
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: When an electric field is applied to an electrolyte-saturated polymer gel embedded with charged colloidal particles, the force that must be exerted by the hydrogel on each particle reflects a delicate balance of electrical, hydrodynamic and elastic stresses. This paper examines the displacement of a single charged spherical inclusion embedded in an uncharged hydrogel. We present numerically exact solutions of coupled electrokinetic transport and elastic-deformation equations, where the gel is treated as an incompressible, elastic Brinkman medium. This model problem demonstrates how the displacement depends on the particle size and charge, the electrolyte ionic strength, and Young's modulus of the polymer skeleton. The numerics are verified, in part, with an analytical (boundary-layer) theory valid when the Debye length is much smaller than the particle radius. Further, we identify a close connection between the displacement when a colloid is immobilized in a gel and its velocity when dispersed in a Newtonian electrolyte. Finally, we describe an experiment where nanometer-scale displacements might be accurately measured using back-focal-plane interferometry. The purpose of such an experiment is to probe physicochemical and rheological characteristics of hydrogel composites, possibly during gelation.
Magnon-mediated quantum battery under systematic errors
Creators: name: Qi, Shi-fan
name: Jing, Jun
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum battery is one of the most prominent micro-devices in the rapid-developing quantum thermodynamics. We propose a quantum charging protocol in which both battery and charger are consisted of a many-spin system. The battery and charger are connected via the Kittle mode of the magnon system, that serves as a charging wire and then enables a long-range charging protocol. Counter-intuitively, we find that the spin-spin couplings insider both battery and charger can be used to promote the charging performance in comparison to the noninteracting condition. And a remarkable promotion is realized at a "sweet" spot in terms of the average coupling strength. Moreover, we apply the quantum-state-diffusion equation to test the robustness of our magnon-mediated charging protocol to the systematic errors about the magnon frequency.
Witnessing the formation of a galaxy cluster at z=0.485: optical and X-ray properties of RX J1117.4+0743 ([VMF 98] 097)
Creators: name: Carrasco, E. R.
name: Cypriano, E. S.
name: Neto, G. B. Lima
name: Cuevas, H.
name: Sodre, L.
name: de Oliveira, C. Mendes
name: Ramirez, A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present a multiwavelength study of the poor cluster RX J1117.4+0743 ([VMF 98] 097) at z=0.485, based on GMOS/Gemini South g', r' photometry and spectroscopy, and XMM-Newton observations. We examine its nature and surroundings by analyzing the projected galaxy distribution, the galaxy velocity distribution, the weak-lensing mass reconstruction, and the X-ray spectroscopy and imaging. The cluster shows a complex morphology. It is composed by at least two structures along the line-of-sight, with velocity dispersions of 592+-82 km s^-1 and 391+-85 km s^-1 respectively. Other structures are also detected in X-ray, in the galaxy projected number density map, and by weak-lensing. One of these clumps, could be gravitationally bound and associated to the main cluster. The derived temperature and bolometric X-ray luminosity reveal that [VMF 98] 097 behave like a normal cluster, in agreement with Lx-Tx correlation found for both local (z=0) and moderate redshift (z~0.4) clusters. We find that the mass determination inferred from weak-lensing is in average 3 to 4.8 times higher (depending on the model assumed) than the X-ray mass. We have two possible explanations for this discrepancy: i) the cluster is in non-equilibrium, then the deviation of the X-ray estimated mass from the true value can be as high as a factor of two; ii) the intervening mass along the line-of-sight of the cluster is producing an over-estimation of the weak-lensing mass. Based on the analysis presented, we conclude that [VMF 98] 097 is a perturbed cluster with at least two substructures in velocity space and with other nearby structures at projected distances of about 1 h^-1 Mpc. This cluster is an example of a poor cluster caught in the process of accreting sub-structures to become a rich cluster.
description: 16 pages, 11 figures.emulateapj.cls style. Accepted for publication in The Astrophysical Journal
Dynamical invariants and nonadiabatic geometric phases in open quantum systems
Creators: name: Sarandy, M. S.
name: Duzzioni, E. I.
name: Moussa, M. H. Y.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We introduce an operational framework to analyze non-adiabatic Abelian and non-Abelian, cyclic and non-cyclic, geometric phases in open quantum systems. In order to remove the adiabaticity condition, we generalize the theory of dynamical invariants to the context of open systems evolving under arbitrary convolutionless master equations. Geometric phases are then defined through the Jordan canonical form of the dynamical invariant associated with the super-operator that governs the master equation. As a by-product, we provide a sufficient condition for the robustness of the phase against a given decohering process. We illustrate our results by considering a two-level system in a Markovian interaction with the environment, where we show that the non-adiabatic geometric phase acquired by the system can be constructed in such a way that it is robust against both dephasing and spontaneous emission.
description: 9 pages, 3 figures. v2: minor corrections and subsection IV.D added. Published version
Spectrum of very excited $Σ_g^+$ flux tubes in SU(3) gauge theory
Creators: name: Bicudo, P.
name: Cardoso, N.
name: Sharifian, A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: Spectra with full towers of levels are expected due to the quantization of the string vibrations, however different theoretical models exist for the excitation spectra. First principle computations are important to test the different models and to search for novel phenomena, but so far only a few excited states of QCD flux tubes have been studied with pure gauge SU(3) lattice QCD in 3+1 dimensions. We thus aim to study a spectrum of flux tubes with static quark and antiquark sources up to a significant number of excitations. We specialize on the spectrum of the most symmetric case, namely $Σ_g^+$, where up to two levels are already published in the literature. To achieve the highest possible excitation level, we construct a large set of operators with the correct symmetry, solve the generalized eigenvalue problem and compare the results of different lattice QCD gauge actions with different lattice spacings and anisotropies.
description: 15 pages, 11 figures and 3 tables
Impact of momentum resolution on factorial moments due to power-law correlations between particles
Creators: name: Samanta, Subhasis
name: Czopowicz, Tobiasz
name: Gazdzicki, Marek
Publisher: name: arXiv
Year: 2021
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The effect of momentum resolution on factorial moments due to the power-law correlation function is studied. The study is motivated by the search for the critical point of the strongly interacting matter in heavy-ion collisions using the intermittency method. We observe that factorial moments are significantly affected by the finite momentum resolution. The effect is superficially significant compared to intuitive expectations. The results depend on the power of the correlation function and the number of uncorrelated particles.
Water circulation, dissolved oxygen, and ammonia concentrations in fish-net cages
Creators: name: Gormican, Stephen Joseph
Publisher: name: University of British Columbia
Year: 2010

description: Fish farming in the protected waters of British Columbia is relatively new, but has undergone a phenomenal growth in the last ten years. Little investigation has been reported with respect to conditions within the net-cages employed in growing salmon at fish farms. In particular, the role of water quality and water exchange has not been examined in relation to local mariculture husbandry practices and hydrography. The first part of this study compared water quality and water flow in two locations, one in Jervis Inlet with a deep entrance sill and the- other in Sechelt Inlet which has a shallow entrance sill. Marked variations in hydrography occurred between the two sites as a result of the differences in sill depth. An internal wave generated at the Sechelt Inlet sill caused daily fluctuations in stratification and hence water properties within the net-cages. No such variations were observed at the Jervis Inlet site. In the second part of this study, water quality and water flow was_ measured in various locations in and near a raft of 24 net-cages. Generally, it was found that within the raft, water flow was diminished in those cages located downstream of the predominate flow direction. However, local topography was thought to have caused marked variation in water quality and water exchange patterns in two of the cages. Ammonia concentrations were not observed to exceed reported sublethal concentrations at any time, over a 25 h period, at any of the depths sampled, within the net-cages. Dissolved oxygen concentrations did, at some depths and times, approach values at which some stress may be felt due to low oxygen. Linear regressions between water quality and water speed were not found to be significant in most cases. The coefficient of determinations were low, indicating that current speed accounted for less than 27% of the variation in water quality.
GRB blastwaves through wind-shaped circumburst media
Creators: name: Meliani, Z.
name: Keppens, R.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Context:A significant fraction of progenitors for long gamma-ray bursts (GRBs) are believed to be massive stars. The investigation of long GRBs therefore requires modeling the propagation of ultra-relativistic blastwaves through the circumburst medium surrounding massive stars. We simulate the expansion of an isotropic, adiabatic relativistic fireball into the wind-shaped medium around a massive GRB progenitor. The circumburst medium is composed of a realistically stratified stellar wind zone up to its termination shock, followed by a region of shocked wind characterized by a constant density. Aims: We followed the evolution of the blastwave through all its stages, including the extremely rapid acceleration up to a Lorentz factor 75 flow, its deceleration by interaction with stellar wind, its passage of the wind termination shock, until its propagation through shocked wind. Methods: We used the adaptive mesh refinement versatile advection code to follow the evolution of the fireball. Results: We show that the acceleration from purely thermal to ultra-relativistic kinetic regimes is abrupt and produces an internally structured blastwave. We resolved the structure of this ultra-relativistic shell in all stages, thanks to the adaptive mesh. We comment on the dynamical roles played by forward and reverse shock pairs in the phase of interaction with the free stellar wind and clearly identify the complex shock-dominated structure created when the shell crosses the terminal shock. Conclusion: We show that in our model where the terminal shock is taken relatively close to the massive star, the phase of self-similar deceleration of Blandford-McKee type can only be produced in the constant density, shocked wind zone.
description: Accepted in A&A Letter (04/04/2007)
Optimization of Apodized Pupil Lyot Coronagraph for ELTs
Creators: name: Martinez, P.
name: Boccaletti, A.
name: Kasper, M.
name: Baudoz, P.
name: Cavarroc, C.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We study the optimization of the Apodized Pupil Lyot Coronagraph (APLC) in the context of exoplanet imaging with ground-based telescopes. The APLC combines an apodization in the pupil plane with a small Lyot mask in the focal plane of the instrument. It has been intensively studied in the literature from a theoretical point of view, and prototypes are currently being manufactured for several projects. This analysis is focused on the case of Extremely Large Telescopes, but is also relevant for other telescope designs. We define a criterion to optimize the APLC with respect to telescope characteristics like central obscuration, pupil shape, low order segment aberrations and reflectivity as function of the APLC apodizer function and mask diameter. Specifically, the method was applied to two possible designs of the future European-Extremely Large Telescope (E-ELT). Optimum configurations of the APLC were derived for different telescope characteristics. We show that the optimum configuration is a stronger function of central obscuration size than of other telescope parameters. We also show that APLC performance is quite insensitive to the central obscuration ratio when the APLC is operated in its optimum configuration, and demonstrate that APLC optimization based on throughput alone is not appropriate.
description: 9 pages, 17 figures, accepted for publication in Astronomy & Astrophysics
Cooling of a Micro-mechanical Resonator by the Back-action of Lorentz Force
Creators: name: Wang, Y. D.
name: Semba, K.
name: Yamaguchi, H.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Using a semi-classical approach, we describe an on-chip cooling protocol for a micro-mechanical resonator by employing a superconducting flux qubit. A Lorentz force, generated by the passive back-action of the resonator's displacement, can cool down the thermal motion of the mechanical resonator by applying an appropriate microwave drive to the qubit. We show that this onchip cooling protocol, with well-controlled cooling power and a tunable response time of passive back-action, can be highly efficient. With feasible experimental parameters, the effective mode temperature of a resonator could be cooled down by several orders of magnitude.
description: 10 pages, 4 figures
N=2 supergravity in three dimensions and its Godel supersymmetric background
Creators: name: Banados, Maximo
name: Faraggi, Alberto T.
name: Theisen, Stefan
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The four dimensional Godel spacetime is known to have the structure M_3 x R. It is also known that the three-dimensional factor M_3 is an exact solution of three-dimensional gravity coupled to a Maxwell-Chern-Simons theory. We build in this paper a N=2 supergravity extension for this action and prove that the Godel background preserves half of all supersymmetries.
Life history stage ratios of Iridaea cordate and factors controlling these ratios in intertidal populations
Creators: name: Green, Lesley Gail
Publisher: name: University of British Columbia
Year: 2010

description: Two populations of Iridaea cordata (Turner) Bory in Vancouver Harbour, Vancouver, British Columbia were examined. Both of the populations alternate between diploid dominance in the winter and haploid dominance in the summer. There was a significant difference between the ratio of diploid to haploid plants at the two sites. The alternation in dominance observed in the population as a whole was also seen in three different size classes (<5cm, 5-15cm and >20 cm) examined. Clearance experiments done in the field indicate that it can take up to 1 year for Iridaea to recolonize a disturbed area. When recolonization does occur the ratio of diploid to haploid plants mirrors the ratio at the time of clearing, not the ratio at the time of regrowth. This suggests that the spores settle when the rocks are cleared but remain dormant until conditions allow for growth and formation of upright plants. The influence of apomeiosis on the number of diploid plants is probably negligible, since only 2% of cultured tetraspores showed evidence of this phenomenon. Some physical characteristics of Iridaea, bearing on reproduction were also explored. Tetrasporophytes and gametophytes have significantly different surface areas, with the gametophytes being larger, and they have significantly different densities of reproductive structures, with the tetrasporophytes having more. As a result, both plant types have statistically the same net number of reproductive structures per plant. There was little difference with respect to surface area or density of reproductive structures between the high and low intertidal plants of either ploidy.
Bright $\mathrm{\textit{ab-initio}}$ photoluminescence of NV+ in diamond
Creators: name: Karim, Akib
name: Lyskov, Igor
name: Russo, Salvy P.
name: Peruzzo, Alberto
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The positively charged nitrogen vacancy (NV+) centre in diamond has been traditionally treated as a dark state due to the experimental lack of an optical signature. Recent computational studies have shown that it is possible for the NV+ defect to have an excited state transition equivalent to that of the negatively charged (NV-) centre, but no PL predictions have been reported so far. We report the first $\mathrm{\textit{ab-initio}}$ calculation showing that the NV+ center presents quantum emission, with zero phonon line at 765 nm and a non-zero transition dipole moment, approximately 4x smaller than the transition dipole moment of NV-. We calculate the energy levels of the multielectron states under time-dependent density functional theory (singlet and triplet E states), and using our recently developed frequency cutoff method, we predict the full PL spectrum. Our results suggest that this state cannot be considered intrinsically 'dark' and charge specific quenching mechanisms should be investigated as the cause of the lack of optical activity in experimental characterizations.
Monte Carlo simulation of uncoupled continuous-time random walks yielding a stochastic solution of the space-time fractional diffusion equation
Creators: name: Fulger, Daniel
name: Scalas, Enrico
name: Germano, Guido
Publisher: name: arXiv
Year: 2007
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We present a numerical method for the Monte Carlo simulation of uncoupled continuous-time random walks with a Levy alpha-stable distribution of jumps in space and a Mittag-Leffler distribution of waiting times, and apply it to the stochastic solution of the Cauchy problem for a partial differential equation with fractional derivatives both in space and in time. The one-parameter Mittag-Leffler function is the natural survival probability leading to time-fractional diffusion equations. Transformation methods for Mittag-Leffler random variables were found later than the well-known transformation method by Chambers, Mallows, and Stuck for Levy alpha-stable random variables and so far have not received as much attention; nor have they been used together with the latter in spite of their mathematical relationship due to the geometric stability of the Mittag-Leffler distribution. Combining the two methods, we obtain an accurate approximation of space- and time-fractional diffusion processes almost as easy and fast to compute as for standard diffusion processes.
description: 7 pages, 5 figures, 1 table. Presented at the Conference on Computing in Economics and Finance in Montreal, 14-16 June 2007; at the conference "Modelling anomalous diffusion and relaxation" in Jerusalem, 23-28 March 2008; etc
A fake doublet solution to the muon anomalous magnetic moment
Creators: name: Anselmi, Damiano
name: Kannike, Kristjan
name: Marzo, Carlo
name: Marzola, Luca
name: Melis, Aurora
name: Müürsepp, Kristjan
name: Piva, Marco
name: Raidal, Martti
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Extensions to the Standard Model that use strictly off-shell degrees of freedom - the fakeons - allow for new measurable interactions at energy scales usually precluded by the constraints that target the on-shell propagation of new particles. Here we employ the interactions between a new fake scalar doublet and the muon to explain the recent Fermilab measurement of its anomalous magnetic moment. Remarkably, unlike in the case of usual particles, the experimental result can be matched for fakeon masses below the electroweak scale without contradicting the stringent precision data and collider bounds on new light degrees of freedom. Our analysis, therefore, demonstrates that the fakeon approach offers unexpected viable possibilities to model new physics naturally at low scales.
description: 7 pages, 5 figures, PRD version
Interferences in the Stochastic Gravitational Wave Background
Creators: name: da Cunha, Disrael Camargo Neves
name: Ringeval, Christophe
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Although the expansion of the Universe explicitly breaks the time-translation symmetry, cosmological predictions for the stochastic gravitational wave background (SGWB) are usually derived under the so-called stationary hypothesis. By dropping this assumption and keeping track of the time dependence of gravitational waves at all length scales, we derive the expected unequal-time (and equal-time) waveform of the SGWB generated by scaling sources, such as cosmic defects. For extinct and smooth enough sources, we show that all observable quantities are uniquely and analytically determined by the holomorphic Fourier transform of the anisotropic stress correlator. Both the strain power spectrum and the energy density parameter are shown to have an oscillatory fine structure, they significantly differ on large scales while running in phase opposition at large wavenumbers $k$. We then discuss scaling sources that are never extinct nor smooth and which generate a singular Fourier transform of the anisotropic stress correlator. For these, we find the appearance of interferences on top of the above-mentioned fine-structure as well as atypical behaviour at small scales. For instance, we expect the rescaled strain power spectrum $k^2 \mathcal{P}_h$ generated by long cosmic strings in the matter era to oscillate around a scale invariant plateau. These singular sources are also shown to produce orders of magnitude difference between the rescaled strain spectra and the energy density parameter suggesting that only the former should be used for making reliable observable predictions. Finally, we discuss how measuring such a fine structure in the SGWB could disambiguate the possible cosmological sources.
description: 40 pages, 7 figures, uses jcappub. References and discussions added, matches published version
Unified approach to electrical and thermal transport in high-$T_c$ superconductors
Creators: name: Boyack, Rufus
name: Wang, Zhiqiang
name: Chen, Qijin
name: Levin, K.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: In this paper we present a consolidated equation for all low-field transport coefficients, based on a reservoir approach developed for non-interacting quasiparticles. This formalism allows us to treat the two distinct types of charged (fermionic and bosonic) quasiparticles that can be simultaneously present, as for example in superconductors. Indeed, in the underdoped cuprate superconductors these two types of carriers result in two onset temperatures with distinct features in transport: $T^*$, where the fermions first experience an excitation (pseudo)gap, and $T_c$, where bosonic conduction processes are dominant and often divergent. This provides the central goal of this paper, which is to address the challenges in thermoelectric transport that stem from having two characteristic temperatures as well as two types of charge carriers whose contributions can in some instances enhance each other and in others compete. We show how essential features of the cuprates (their bad-metal character and the presence of Fermi arcs) provide an explanation for the classic pseudogap onset signatures at $T^*$ in the longitudinal resistivity, $ρ_{xx}$. Based on the fits to the temperature-dependent $ρ_{xx}$, we present the implications for all of the other thermoelectric transport properties.
description: Published version
Towards a trustful digital world: exploring self-sovereign identity ecosystems
Creators: name: Laatikainen, Gabriella
name: Kolehmainen, Taija
name: Li, Mengcheng
name: Hautala, Markus
name: Kettunen, Antti
name: Abrahamsson, Pekka
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: In the current global situation-burdened by, among others, a vast number of people without formal identification, digital leap, the need for health passports and contact tracking applications-providing private and secure digital identity for individuals, organizations and other entities is crucial. The emerging self-sovereign identity (SSI) solutions rely on distributed ledger technologies and verifiable credentials and have the potential to enable trustful digital interactions. In this human-centric paradigm, trust among actors can be established in a decentralized manner while the identity holders are able to own and control their confidential data. In this paper, we build on observations gathered in a field study to identify the building blocks, antecedents and possible outcomes of SSI ecosystems. We also showcase opportunities for researchers and practitioners to investigate this phenomenon from a wide range of domains and theories, such as the digital innovation ecosystems, value co-creation, surveillance theory, or entrepreneurship theories.
description: This is a preprint of an article published in the PACIS 2021 Proceedings. Recommended citation: Laatikainen, Gabriella; Kolehmainen, Taija; Li, Mengcheng; Hautala, Markus; Kettunen, Antti; and Abrahamsson, Pekka, "Towards a Trustful Digital World: Exploring Self-Sovereign Identity Ecosystems" (2021). PACIS 2021 Proceedings. 19. https://aisel.aisnet.org/pacis2021/19
The Eternal Sunshine of the Spotless Mind
Creators: name: Easther, Richard
name: Lim, Eugene A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We extend the worldline measure for pocket formation in eternal inflation to allow for time-ordered bubble formation. Such a time-ordering is equivalent to imposing a preferred time-slicing on the "parent" de Sitter space. Using this measure, we describe a covariant version of the youngness paradox and show that the youngness paradox is a gauge artifact if the parent spacetime is an unbroken de Sitter space, due to the lack of an explicit time-ordering for the bubble nucleation events. We then show that one can add a "clock" to the de Sitter space, in the form of a vector field with a spontaneously broken symmetry that defines a unique timelike direction accessible to all observers. Once this is done, the existence of a preferred slicing means that the youngness paradox cannot be easily resolved. We use this to elucidate the apparent "persistence of memory" discussed recently by Garriga, Guth and Vilenkin, for inflationary universes produced by bubble nucleation.
description: 18 pages, 5 figures
Anti-Poiseuille flow in neutral graphene
Creators: name: Narozhny, B. N.
name: Gornyi, I. V.
name: Titov, M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Hydrodynamic flow of charge carriers in graphene is an energy flow unlike the usual mass flow in conventional fluids. In neutral graphene, the energy flow is decoupled from the electric current, making it difficult to observe the hydrodynamic effects and measure the viscosity of the electronic fluid by means of electric current measurements. In particular, we show that the hallmark Poiseuille flow in a narrow channel cannot be driven by the electric field irrespective of boundary conditions at the channel edges. Nevertheless one can observe nonuniform current densities similarly to the case of the well-known ballistic-diffusive crossover. The standard diffusive behavior with the uniform current density across the channel is achieved under the assumptions of specular scattering on the channel boundaries. This flow can also be made nonuniform by applying weak magnetic fields. In this case, the curvature of the current density profile is determined by the quasiparticle recombination processes dominated by the disorder-assisted electron-phonon scattering -- the so-called supercollisions.
description: 12pages, 2 figures
การพัฒนาผลสัมฤทธิ์ทางการเรียนรายวิชานวัตกรรมและเทคโนโลยีสารสนเทศทางการศึกษา โดยใช้อีเลิร์นนิงและการเรียนรู้แบบร่วมมือ ของนักศึกษาชั้นปีที่ 2 คณะศิลปศึกษาสถาบันบัณฑิตพัฒนศิลป์
Creators: name: พิชญา ดำนิล
Publisher: name: Walailak University
Year: 2019
Subjects: ผลสัมฤทธิ์ทางการเรียน
อีเลิร์นนิง
การเรียนแบบร่วมมือ

description: วารสารนวัตกรรมการเรียนรู้ มหาวิทยาลัยวลัยลักษณ์, 5, 1, 101-126
Is diversity good?
Creators: name: Bouville, Mathieu
Publisher: name: arXiv
Year: 2007
Subjects: subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: Prominent ethical and policy issues such as affirmative action and female enrollment in science and engineering revolve around the idea that diversity is good. However, even though diversity is an ambiguous concept, a precise definition is seldom provided. We show that diversity may be construed as a factual description, a craving for symmetry, an intrinsic good, an instrumental good, a symptom, or a side effect. These acceptions differ vastly in their nature and properties. The first one cannot lead to any action and the second one is mistaken. Diversity as intrinsic good is a mere opinion, which cannot be concretely applied; moreover, the most commonly invoked forms of diversity (sexual and racial) are not intrinsically good. On the other hand, diversity as instrumental good can be evaluated empirically and can give rise to policies, but these may be very weak. Finally, symptoms and side effects are not actually about diversity. We consider the example of female enrollment in science and engineering, interpreting the various arguments found in the literature in light of this polysemy. Keywords: ethics, policy, higher education, female students, minority students, affirmative action
description: 7 pages
Six Conjectures which Generalize or Are Related to Andrica's Conjecture
Creators: name: Smarandache, Florentin
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Mathematics (math.GM)
subject: FOS: Mathematics
subject: 11A67

description: Six conjectures on pairs of consecutive primes are listed in this paper, together with examples for each case.
description: 3 pages
Dirac quasinormal modes of D-dimensional de Sitter spacetime
Creators: name: Lopez-Ortega, A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We find exact solutions to the Dirac equation in D-dimensional de Sitter spacetime. Using these solutions we analytically calculate the de Sitter quasinormal (QN) frequencies of the Dirac field. For the massive Dirac field this computation is similar to that previously published for massive fields of half-integer spin moving in four dimensions. However to calculate the QN frequencies of the massless Dirac field we must use distinct methods in odd and even dimensions, therefore the computation is different from that already known for other massless fields of integer spin.
description: 19 pages
Effect of suppressed excitation on the amplitude distribution of 5-min oscillations in sunspots
Creators: name: Parchevsky, K. V.
name: Kosovichev, A. G.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Five-minute oscillations on the Sun (acoustic and surface gravity waves) are excited by subsurface turbulent convection. However, in sunspots the excitation is suppressed because strong magnetic field inhibits convection. We use 3D simulations to investigate how the suppression of excitation sources affects the distribution of the oscillation power in sunspot regions. The amplitude of random acoustic sources was reduced in circular-shaped regions to simulate the suppression in sunspots. The simulation results show that the amplitude of the oscillations can be approximately 2-4 times lower in the sunspot regions in comparison to the quiet Sun, just because of the suppressed sources. Using SOHO/MDI data we measured the amplitude ratio for the same frequency bands outside and inside sunspots, and found that this ratio is approximately 3-4. Hence, the absence of excitation sources inside sunspots makes a significant contribution (about 50% or higher) to the observed amplitude ratio and must be taken into account in sunspot seismology.
description: 12 pages, 5 figures, accepted to ApJL
The young, wide and very low mass visual binary LOri167
Creators: name: Navascues, D. Barrado y
name: Bayo, A.
name: Morales-Calderon, M.
name: Huelamo, N.
name: Stauffer, J. R.
name: Bouy, H.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We look for wide, faint companions around members of the 5 Myr Lambda Orionis open cluster. We used optical, near-infrared, and Spitzer/IRAC photometry. We report the discovery of a very wide very low mass visual binary, LOri167, formed by a brown dwarf and a planetary-mass candidate located at 5 arcsec, which seems to belong to the cluster. We derive Teff of 2125 and 1750 K. If they are members, comparisons with theoretical models indicate masses of 17 (20-15) Mjup and 8 (13-7) Mjup, with a projected separation of 2000 AU. Such a binary system would be difficult to explain in most models, particularly those where substellar objects form in the disks surrounding higher mass stars.
description: Astronomy & Astrophysics Letters, in press
Anomalous diffusion and Lévy walks distinguish active from inertial turbulence
Creators: name: Mukherjee, Siddhartha
name: Singh, Rahul K.
name: James, Martin
name: Ray, Samriddhi Sankar
Publisher: name: arXiv
Year: 2021
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Chaotic Dynamics (nlin.CD)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Bacterial swarms display intriguing dynamical states like active turbulence. Using a hydrodynamic model we now show that such dense active suspensions manifest super-diffusion, via Lévy walks, which masquerades as a crossover from ballistic to diffusive scaling in measurements of mean-squared-displacements, and is tied to the emergence of hitherto undetected oscillatory streaks in the flow. Thus, while laying the theoretical framework of an emergent advantageous strategy in the collective behaviour of microorganisms, our study underlines the essential differences between active and inertial turbulence.
description: 7 pages, 7 figures; Minor change in title; Published in Physical Review Letters: https://doi.org/10.1103/PhysRevLett.127.118001
The Shared Reward Dilemma
Creators: name: Cuesta, J. A.
name: Jimenez, R.
name: Lugo, H.
name: Sanchez, A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: FOS: Biological sciences

description: One of the most direct human mechanisms of promoting cooperation is rewarding it. We study the effect of sharing a reward among cooperators in the most stringent form of social dilemma, namely the Prisoner's Dilemma. Specifically, for a group of players that collect payoffs by playing a pairwise Prisoner's Dilemma game with their partners, we consider an external entity that distributes a fixed reward equally among all cooperators. Thus, individuals confront a new dilemma: on the one hand, they may be inclined to choose the shared reward despite the possibility of being exploited by defectors; on the other hand, if too many players do that, cooperators will obtain a poor reward and defectors will outperform them. By appropriately tuning the amount to be shared a vast variety of scenarios arises, including traditional ones in the study of cooperation as well as more complex situations where unexpected behavior can occur. We provide a complete classification of the equilibria of the $n$-player game as well as of its evolutionary dynamics.
description: Major rewriting, new appendix, new figures
Discontinuity of the Lempert function and the Kobayashi--Royden metric of the spectral ball
Creators: name: Nikolov, Nikolai
name: Thomas, Pascal J.
name: Zwonek, Wlodzimierz
Publisher: name: arXiv
Year: 2007
Subjects: subject: Complex Variables (math.CV)
subject: FOS: Mathematics
subject: Primary: 32F45; Secondary: 32A07

description: Some results on the discontinuity properties of the Lempert function and the Kobayashi pseudometric in the spectral ball are given.
description: After submitting this paper to a journal in January the authors received a paper by G. Bharali (see arXiv:0704.1966), where some of the problems are similar to that in our paper