cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Dynamics of the Magnetic Flux Trapped in Fractal Clusters of a Normal Phase in Percolative Superconductors
Creators: name: Kuzmin, Yuriy I.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The effect of the fractal clusters of a normal phase, which act as pinning centers, on the dynamics of magnetic flux in percolative type-II superconductor is considered. The main features of these clusters are studied in detail: the cluster statistics is analyzed; the fractal dimension of their boundary is estimated; the distribution of critical currents is obtained, and its peculiarities are explored. It is found that there is the range of fractal dimension where this distribution has anomalous statistical properties, specifically, its dispersion becomes infinite. It is examined how the finite resolution capacity of the cluster geometric size measurement affects the estimated value of fractal dimension. The effect of fractal properties of the normal phase clusters on the electric field arisen from magnetic flux motion is investigated for the cluster area distribution of different kinds. The voltage-current characteristics of fractal superconducting structures in the resistive state are obtained for an arbitrary fractal dimension. It is revealed that the fractality of the boundaries of the normal phase clusters intensifies the magnetic flux trapping and thereby raises the critical current of a superconductor.
description: Invited Talk at NATO Advanced Research Workshop "Vortex Dynamics in High Temperature Superconductors", Chimgan Mts., Uzbekistan, May 17-22 (2002); 13 pages, 9 figures, 55 refs
Linear Abadi and Plotkin Logic
Creators: name: Birkedal, Lars
name: Møgelberg, Rasmus E.
name: Petersen, Rasmus Lerchedahl
Publisher: name: arXiv
Year: 2006
Subjects: subject: Logic in Computer Science (cs.LO)
subject: FOS: Computer and information sciences
subject: F.4.1; D.3.3

description: We present a formalization of a version of Abadi and Plotkin's logic for parametricity for a polymorphic dual intuitionistic/linear type theory with fixed points, and show, following Plotkin's suggestions, that it can be used to define a wide collection of types, including existential types, inductive types, coinductive types and general recursive types. We show that the recursive types satisfy a universal property called dinaturality, and we develop reasoning principles for the constructed types. In the case of recursive types, the reasoning principle is a mixed induction/coinduction principle, with the curious property that coinduction holds for general relations, but induction only for a limited collection of ``admissible'' relations. A similar property was observed in Pitts' 1995 analysis of recursive types in domain theory. In a future paper we will develop a category theoretic notion of models of the logic presented here, and show how the results developed in the logic can be transferred to the models.
Note esegetiche e testuali alla 'Descriptio orbis' di Dionisio d’Alessandria (III)
Creators: name: Amato, Eugenio
Publisher: name: Göttinger Forum für Altertumswissenschaft
Year: 2021

description: Göttinger Forum für Altertumswissenschaft, Bd. 7 (2004): Göttinger Forum für Altertumswissenschaft
New Hadron States
Creators: name: Zhu, Shi-Lin
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Lattice (hep-lat)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The past four years has witnessed the renaissance of the hadron spectroscopy. Many interesting new hadron states were discovered experimentally, some of which do not fit into the quark model easily. I will give a concise overview of these states and their possible interpretations. Topics covered in this review are: (1) candidates of new light hadrons including $p {\bar p}$ threshold enhancement, X(1835), X(1576), $f_0(1810)$, recent candidates of the $1^{-+}$ exotic mesons, Y(2175), $p\barΛ$ threshold enhancement etc; (2) charmed mesons including p-wave non-strange charmed mesons, $D_{sj}(2317)$ and $D_{sj}(2460)$, recent candidates of higher excited charmed mesons, $D_{sj}(2632)$ etc; (3) charmonium and charmonium-like states such as X(3872), Y(4260), X(3940), Y(3940), Z(3930) etc. The effect from the nearby S-wave open channels on the quark model spectrum above or near strong decay threshold is emphasized. Dynamical lattice simulations of $D K$ and $D^0\bar D^{\ast 0}$ scattering and the extraction of their phase shifts may help resolve the underlying structure of $D_{sj}(2317)$, $D_{sj}(2460)$ and X(3872).
description: Brief review, 29 pages, comments and suggestions welcome
Branching Ratio and CP-asymmetry for B-> 1^{1}P_{1}gamma decays
Creators: name: Aslam, M. Jamil
name: Riazuddin
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We calculate the branching ratios for B_{d}^{0}->(b_{1},h_{1})gamma at next-to-leading order (NLO) of alpha_{s} where b_{1} and h_{1} are the corresponding radially excited axial vector mesons of rho and omega respectively. Using the SU(3)symmetry for the form factor, the branching ratio for B_{d}^{0}->(b_{1},h_{1})gamma is expressed in terms of the branching ratio of the B_{d}^{0}-> K_{1}gamma and it is found to be B(B_{d}^{0}->b_{1}gamma)=0.71* 10^{-6} and B(B_{d}^{0}-> h_{1}gamma) =0.74*10^{-6}. We also calculate direct CP asymmetry for these decays and find, in confirmity with the observations made in the literature, that the hard spectator contributions significantely reduces the asymmetry arising from the vertex corrections alone. The value of CP-asymmetry is 10% and is negative like rho and omega in the Standard Model.
description: 10 pages, 2 figures
Chapter 1-3
Creators: name: Lullaby Cry
Publisher: name: figshare
Year: 2021
Subjects: subject: 80611 Information Systems Theory
subject: FOS: Computer and information sciences
subject: 80609 Information Systems Management
subject: 120201 Building Construction Management and Project Planning
subject: FOS: Civil engineering

description: project management; organizational theory; risk; oil and gas construction
Design of performance indicators for Angola's scientific and publishing activity in Open Access
Creators: name: United Nations Educational, Scientific and Cultural Organization
name: Ministério Do Ensino Superior, Ciência
name: Redalyc-Universidad Autónoma Del Estado De México
name: AmeliCA
name: Universidade Óscar Ribas
Publisher: name: Zenodo
Year: 2022
Subjects: Open Access
Angola
Africa
Performance indicators
Angola's scientific activity
Angola's editorial activity

description: Work derived from the collaborative project among Redalyc UAEM, AmeliCA, MESCTI and U. Óscar Ribas funded by UNESCO for the development of an Open Access strategy in Angola. Vol. 17 of 38
description: {"references": ["Aguado-Lopez, E., Becerril-Garcia, A., Macedo-Garcia, A., Godinez-Larios, S. & Gonz\u00e1lezMorales, L. (2022). Metodolog\u00eda para la evaluaci\u00f3n de la ciencia en Acceso Abierto Diamante. Santiago de Chile: Ariadna Ediciones."]}
The Spatial Averaging Limit of Covariant Macroscopic Gravity - Scalar Corrections to the Cosmological Equations
Creators: name: Paranjape, Aseem
name: Singh, T. P.
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Astrophysics (astro-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: It is known that any explicit averaging scheme of the type essential for describing the large scale behaviour of the Universe, must necessarily yield corrections to the Einstein equations applied in the Cosmological setting. The question of whether or not the resulting corrections to the Einstein equations are significant, is still a subject of debate, partly due to possible ambiguities in the averaging schemes available. In particular, it has been argued in the literature that the effects of averaging could be gauge artifacts. We apply the formalism of Zalaletdinov's Macroscopic Gravity (MG) which is a fully covariant and nonperturbative averaging scheme, in an attempt to construct gauge independent corrections to the standard Friedmann-Lemaitre-Robertson-Walker (FLRW) equations. We find that whereas one cannot escape the problem of dependence on \emph{one} gauge choice -- which is inherent in the assumption of large scale homogeneity and isotropy -- it is however possible to construct \emph{spacetime scalar} corrections to the standard FLRW equations. This partially addresses the criticism concerning the corrections being gauge artifacts. For a particular initial choice of gauge which simplifies the formalism, we explicitly construct these scalars in terms of the underlying inhomogeneous geometry, and incidentally demonstrate that the formal structure of the corrections with this gauge choice is identical to that of analogous corrections derived by Buchert in the context of spatial averaging of scalars.
description: 18 pages, no figures, revtex4; v2 - minor clarifications added; v3 - minor changes in presentation to improve clarity, reference added, to appear in Phys. Rev. D
Efficient initial designs for binary response data
Creators: name: Karvanen, Juha
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistics Theory (math.ST)
subject: Methodology (stat.ME)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: 62L05; 62K05; 62P35

description: In this paper we introduce a binary search algorithm that efficiently finds initial maximum likelihood estimates for sequential experiments where a binary response is modeled by a continuous factor. The problem is motivated by switching measurements on superconducting Josephson junctions. In this quantum mechanical experiment, the current is the factor controlled by the experimenter and a binary response indicating the presence or the absence of a voltage response is measured. The prior knowledge on the model parameters is typically poor, which may cause the common approaches of initial estimation to fail. The binary search algorithm is designed to work reliably even when the prior information is very poor. The properties of the algorithm are studied in simulations and an advantage over the initial estimation with equally spaced factor levels is demonstrated. We also study the cost-efficiency of the binary search algorithm and find the approximately optimal number of measurements per stage when there is a cost related to the number of stages in the experiment. KEY WORDS: optimal design, binary search, logistic regression, complementary log-log, quantum physics, switching measurement
Network of recurrent events for the Olami-Feder-Christensen model
Creators: name: Peixoto, Tiago P.
name: Davidsen, Joern
Publisher: name: arXiv
Year: 2008
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: We numerically study the dynamics of a discrete spring-block model introduced by Olami, Feder and Christensen (OFC) to mimic earthquakes and investigate to which extent this simple model is able to reproduce the observed spatiotemporal clustering of seismicty. Following a recently proposed method to characterize such clustering by networks of recurrent events [Geophys. Res. Lett. {\bf 33}, L1304, 2006], we find that for synthetic catalogs generated by the OFC model these networks have many non-trivial statistical properties. This includes characteristic degree distributions -- very similar to what has been observed for real seismicity. There are, however, also significant differences between the OFC model and earthquake catalogs indicating that this simple model is insufficient to account for certain aspects of the spatiotemporal clustering of seismicity.
description: 11 pages, 16 figures
Analysis of physical processes in eruptive YSOs with near infrared spectra and multi-wavelength light curves
Creators: name: Guo, Zhen
name: Lucas, P. W.
name: Peña, C. Contreras
name: Smith, L. C.
name: Morris, C.
name: Kurtev, R. G.
name: Borissova, J.
name: Alonso-García, J.
name: Minniti, D.
name: Chené, A. -N.
name: Kumar, M. S. N.
name: Garatti, A. Caratti o
name: Froebrich, D.
name: Stimson, W. H.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The decade-long Vista Variables in the Via Lactea (VVV) survey has detected numerous highly variable young stellar objects (YSOs). We present a study of 61 highly variable VVV YSOs ($ΔK_s$ = 1-5 mag), combining near infrared spectra from Magellan and VLT with VVV and NEOWISE light curves to investigate physical mechanisms behind eruptive events. Most sources are spectroscopically confirmed as eruptive variables (typically Class I YSOs) but variable extinction is also seen. Among them, magnetically controlled accretion, identified by H{\sc i} recombination emission (usually accompanied by CO emission), is observed in 46 YSOs. Boundary layer accretion, associated with FU Ori-like outbursts identified by CO overtone and H$_2$O absorption, is observed only in longer duration events ($\ge$5 yr total duration). However, even in long duration events, the magnetically controlled accretion mode predominates, with amplitudes similar to the boundary layer mode. Shorter (100-700 days) eruptive events usually have lower amplitudes and these events are generally either periodic accretors or multiple timescale events, wherein large photometric changes occur on timescales of weeks and years. We find that the ratio of amplitudes in $K_s$ and $W2$ can distinguish between variable accretion and variable extinction. Several YSOs are periodic or quasi-periodic variables. We identify examples of periodic accretors and extinction-driven periodicity among them (with periods up to 5 yr) though more data are needed to classify some cases. The data suggest that dynamic interactions with a companion may control the accretion rate in a substantial proportion of eruptive systems, although star-disc interactions should also be considered.
description: 37 pages, 16 figures. Submitted to MNRAS
Discovery of a Young Substellar Companion in Chamaeleon
Creators: name: Luhman, K. L.
name: Wilson, J. C.
name: Brandner, W.
name: Skrutskie, M. F.
name: Nelson, M. J.
name: Smith, J. D.
name: Peterson, D. E.
name: Cushing, M. C.
name: Young, E.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: During an imaging survey of the Chamaeleon I star-forming region with the ACS aboard HST, we have discovered a candidate substellar companion to the young low-mass star CHXR 73 (~2 Myr, M=0.35 Msun). We measure a projected separation of 1.3+/-0.03" for the companion, CHXR 73 B, which corresponds to 210 AU at the distance of the cluster. A near-infrared spectrum of this source obtained with CorMASS at the Magellan II telescope exhibits strong steam absorption that confirms its late-type nature (>=M9.5). In addition, the gravity-sensitive shapes of the H- and K-band continua demonstrate that CHXR 73 B is a young, pre-main-sequence object rather than a field star. The probability that CHXR 73A and B are unrelated members of Chamaeleon I is ~0.001. We estimate the masses of CHXR 73 B and other known substellar companions in young clusters with a method that is consistent with the dynamical measurements of the eclipsing binary brown dwarf 2M 0535-0546, which consists of a comparison of the bolometric luminosities of the companions to the values predicted by the evolutionary models of Chabrier & coworkers and Burrows & coworkers. We arrive at mass estimates of 0.003-0.004, 0.024+/-0.012, 0.011+0.01/-0.003, and 0.012+0.008/-0.005 Msun for 2M 1207-3932 B, GQ Lup B, DH Tau B, and CHXR 73 B, respectively. Thus, DH Tau B and CHXR 73 B appear to be the least massive companions to stars outside the solar system that have been detected in direct images, and may have masses that are within the range observed for extrasolar planetary companions (M<=0.015 Msun). However, because these two objects (as well as 2M 1207-3932 B) probably did not form within circumstellar disks around their primaries, we suggest that they should be viewed as brown dwarf companions rather than planets.
description: Astrophysical Journal, in press
Novel Self-Sustained Modulation in Superconducting Stripline Resonators
Creators: name: Segev, Eran
name: Abdo, Baleegh
name: Shtempluck, Oleg
name: Buks, Eyal
Publisher: name: arXiv
Year: 2006
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We study thermal instability in a driven superconducting NbN resonator integrated with a microbridge. A monochromatic input drive is injected into the resonator and the response is measured as a function of the frequency and amplitude of the drive. Inside a certain zone in the frequency-amplitude plane the system has no steady state, and consequently self-sustained modulation of the reflected power off the resonator is generated. A theoretical model, according to which the instability originates by a hot spot forming in the microbridge, exhibits a good quantitative agreement with the experimental results.
Natural coordinates for a class of Benenti systems
Creators: name: Blaszak, Maciej
name: Sergyeyev, Artur
Publisher: name: arXiv
Year: 2006
Subjects: subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: Mathematical Physics (math-ph)
subject: Differential Geometry (math.DG)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We present explicit formulas for the coordinates in which the Hamiltonians of the Benenti systems with flat metrics take natural form and the metrics in question are represented by constant diagonal matrices.
description: LaTeX 2e, 8 p., no figures; extended version with enlarged bibliography
High-quality Spectrophotometry of the Planetary Nebula in the Fornax dSph
Creators: name: Kniazev, A. Y.
name: Grebel, E. K.
name: Pustilnik, S. A.
name: Pramskij, A. G.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present results of NTT spectroscopy of the one known planetary nebula (PN) in the dwarf spheroidal galaxy Fornax, a gas-deficient Local Group galaxy that stopped its star formation activity a few hundred million years ago. We detected the [OIII] 4363 line with a signal-to-noise ratio of ~22. For the first time we detected the weak [SII] 6717,6731 lines (I(6717+6731) ~0.01 I(Hbeta)), determined the electron number density (Ne(SII) = 750 cm^-3), and calculated O, N, Ne, Ar, S, Cl, Fe, He and C abundances. The abundance analysis presented here is based on the direct calculation of the electron temperature Te and yields an oxygen abundance of 12+log(O/H) = 8.28+/-0.02. The analysis of the O, Ne, Ar and S abundances shows that the original ISM oxygen abundance was 0.27+/-0.10 dex lower and that third-dredge-up self-pollution in oxygen took place. The blue spectrum shows weak Wolf-Rayet features, and the progenitor star is classified as a weak emission-line star. Four of the five PNe in dwarf spheroidal galaxies are now known to show WR wind features. Overall, the metallicity of the progenitor of the PN fits in well with stellar spectroscopic abundances derived in previous studies as well as with the stellar age-metallicity relation of Fornax.
description: 9 pages, 3 figures, accepted for publication by A&A
A study on black-body radiation: classical and binary photons
Creators: name: Varro, Sandor
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The present study gives a detailed analysis of the black-body radiation based on classical random variables. It is shown that the energy of a mode of a chaotic radiation field (Gauss variable) can be uniquely decomposed into a sum of a discrete variable (Planck variable having the Planck-Bose distribution) and a continuous dark variable (with a truncated exponential distribution of finite support). The Planck variable is decomposed, on one hand, into a sum of binary variables representing the binary photons of energies 2^s*h*nu with s=0,1,2,etc. In this way the black-body radiation can be viewed as a mixture of thermodinamically independent fermion gases. The Planck variable can also be decomposed into a sum of independent Poisson components representing the classical photo-molecules of energies m*h*nu with m=1,2,3,etc. These classical photons have only particle-like fluctuations, on the other hand, the binary photons have wave-particle fluctuations of fermionic character.
description: 20 pages
Theoretical Study of Extrinsic Spin-current Generation in Ferromagnets Induced by Anisotropic Spin-flip Scattering
Creators: name: Yahagi, Yuta
name: Zelezny, Jakub
name: Miura, Daisuke
name: Sakuma, Akimasa
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The spin Hall effect (SHE) and the magnetic spin Hall effect (MSHE) are responsible for electrical spin current generation, which is a key concept of modern spintronics. We theoretically investigated the spin conductivity induced by spin-dependent s-d scattering in a ferromagnetic 3d alloy model by employing microscopic transport theory based on the Kubo formula. We derived a novel extrinsic mechanism that contributes to both the SHE and MSHE. This mechanism can be understood as the contribution from anisotropic (spatial-dependent) spin-flip scattering due to the combination of the orbital-dependent anisotropic shape of s-d hybridization and spin flipping, with the orbital shift caused by spin-orbit interaction with the d-orbitals. We also show that this mechanism is valid under crystal-field splitting among the d-orbitals in either the cubic or tetragonal symmetry.
description: 34 pages, 15 figures
Collisional Properties of p-Wave Feshbach Molecules
Creators: name: Inada, Yasuhisa
name: Horikoshi, Munekazu
name: Nakajima, Shuta
name: Kuwata-Gonokami, Makoto
name: Ueda, Masahito
name: Mukaiyama, Takashi
Publisher: name: arXiv
Year: 2008
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We detected the formation of p-wave Feshbach molecules for all three combinations of the two lowest atomic spin states of 6Li. By creating a pure molecular sample in an optical trap, we measured the inelastic collision rates of p-wave molecules. The elastic collision rate was measured from the thermalization rate of a breathing mode excited spontaneously upon molecular formation.
The Yin and Yang of High Energy Chromodynamics: Scattering in Black and White
Creators: name: Kovner, Alex
name: Lublinsky, Michael
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We further discuss the QCD Reggeon field theory (RFT) as it emerges from the JIMWLK/KLWMIJ evolution equation and beyond. We give an explicit expression for the calculation of scattering amplitude in terms of the eigenstates of the RFT Hamiltonian. We point out that the spectrum of RFT is doubly degenerate, the degeneracy being related to the spontaneous breaking of the Dense-Dilute Duality symmetry of RFT. The degeneracy is between the "almost white" states (the Yang sector) which contain a small number of gluons, and "almost black" states (the Yin sector). The excitations above the Yang vacuum have natural interpretation in terms of gluons. Analogously the excitations above the Yin vacuum have natural interpretation as "holes" in the black disk - points at which an incoming gluon does not scatter with unit probability. We discuss in detail the spectrum of the "parton model approximation" to the KLWMIJ evolution introduced in our previous paper, and prove that it is explicitly selfdual. This allows us to find explicitly the counterpart hole states in this approximation. We also present an argument to the effect that the end point of the evolution for any physical state cannot be a "grey disk" but must necessarily be the "black disk" Yin vacuum state. Finally, we suggest an approximation scheme for including the Pomeron loop contribution to the evolution which requires only the solution of the JIMWLK/KLWMIJ Hamiltonian.
description: 25 pages, 1 figure
Charged black holes and unusual wormholes in scalar-tensor gravity
Creators: name: Bronnikov, K. A.
name: Chernakova, M. S.
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We consider static, spherically symmetric, electrically or/and magnetically charged configurations of a minimally coupled scalar field with an arbitrary potential $V(ϕ)$ in general relativity. Using the inverse problem method, we obtain a four-parameter family of asymptotically dS, flat and AdS solutions, including those with naked singularities and both extreme and non-extreme black-hole (BH) solutions. The parameters are identified as the asymptotic cosmological constant, an arbitrary length scale, mass and charge. In all asymptotically flat BH solutions, the potential $V(ϕ)$ is partly negative, in accord with Bekenstein and Mayo's no-hair theorem. The well-known conformal mapping extends the BH solutions to Jordan's pictures of a general class of scalar-tensor theories (STT) of gravity under the condition that the nonminimal coupling function $f(ϕ)$ is everywhere positive. Relaxing the latter condition and assuming $f=0$ at some value of $ϕ$, we obtain wormhole solutions in a particular subclass of STT. In such solutions, the double horizon of an extreme BH in Einstein's picture maps into the second spatial infinity in Jordan's. However, at this second infinity, the effective gravitational coupling infinitely grows.
description: 5 pages, 3 figures, GC style
Single Particle Tunneling in Strongly Driven Double Well Potentials
Creators: name: Kierig, E.
name: Schnorrberger, U.
name: Schietinger, A.
name: Tomkovic, J.
name: Oberthaler, M. K.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We report on the first direct observation of coherent control of single particle tunneling in a strongly driven double well potential. In our setup atoms propagate in a periodic arrangement of double wells allowing the full control of the driving parameters such as frequency, amplitude and even the space-time symmetry. Our experimental findings are in quantitative agreement with the predictions of the corresponding Floquet theory and are also compared to the predictions of a simple two mode model. Our experiments reveal directly the critical dependence of coherent destruction of tunneling on the generalized parity symmetry.
description: 4 pages, 5 figures
Infrared and THz studies of polar phonons and improper magnetodielectric effect in multiferroic BFO3 ceramics
Creators: name: Kamba, S.
name: Nuzhnyy, D.
name: Savinov, M.
name: Sebek, J.
name: Petzelt, J.
name: Prokleska, J.
name: Haumont, R.
name: Kreisel, J.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: BFO3 ceramics were investigated by means of infrared reflectivity and time domain THz transmission spectroscopy at temperatures 20 - 950 K, and the magnetodielectric effect was studied at 10 - 300 K, with the magnetic field up to 9 T. Below 175 K, the sum of polar phonon contributions into the permittivity corresponds to the value of measured permittivity below 1 MHz. At higher temperatures, a giant low-frequency permittivity was observed, obviously due to the enhanced conductivity and possible Maxwell-Wagner contribution. Above 200 K the observed magnetodielectric effect is caused essentially through the combination of magnetoresistance and the Maxwell-Wagner effect, as recently predicted by Catalan (Appl. Phys. Lett. 88, 102902 (2006)). Since the magnetodielectric effect does not occur due to a coupling of polarization and magnetization as expected in magnetoferroelectrics, we call it improper magnetodielectric effect. Below 175 K the magnetodielectric effect is by several orders of magnitude lower due to the decreased conductivity. Several phonons exhibit gradual softening with increasing temperature, which explains the previously observed high-frequency permittivity increase on heating. The observed non-complete phonon softening seems to be the consequence of the first-order nature of the ferroelectric transition.
description: subm. to PRB. revised version according to referees' reports
D3.2. Documents for engaging the policy-makers, including a plan for standardization of PPB-based products of COST Action PurpleGain CA21146
Creators: name: King Juan Carlos University
Publisher: name: Zenodo
Year: 2024
Subjects: purplegain

description: WG3 is focused on the relationships among academia, industry, and public entities related to the production and use of biomasses of purple phototrophic bacteria (PPB) and associated bioproducts. Some products examples from PPB are single-cell proteins, polyhydroxyalkanoates, carotenoids,  or nutrient-rich biomass. The deliverable D3.1 showed the state of the art of PPB-based technologies currently used in different sectors across the biotechnology, food, and environmental industries, among others. An analysis of how similar and competing technologies are used will be made to establish benchmarks for PPB, as well as how the potential PPB-based products fit over the current policy practices in the EU and overseas, trying to fill the gap between direct engagement with policymakers.
Resummed one-loop determination of the phase boundary of the SU(3)_R x SU(3)_L linear sigma model in the m_pi-m_K-plane
Creators: name: Herpay, T.
name: Szep, Zs.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Complete one-loop parametrization of the linear sigma model is performed and the phase boundary between first order and crossover transition regions of the m_pi-m_K-plane is determined using the optimized perturbation theory as a resummation tool of perturbative series. Away from the physical point the parameters of the model were determined by making use of chiral perturbation theory. Along the diagonal m_pi=m_K of the mass--plane we estimate m_pi^c=110 +- 20 MeV. The location of the tricritical point on the m_pi=0 axis is estimated in the interval m_K^TCP in (1700,1850) MeV.
description: RevTeX4, 11 pages, 6 figures, with macro package feynmf
The Challenges of Assessing and Evaluating the Students at Distance
Creators: name: Almeida, Fernando
name: Monteiro, José
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: The COVID-19 pandemic has caused a strong effect on higher education institutions with the closure of classroom teaching activities. In this unprecedented crisis, of global proportion, educators and families had to deal with unpredictability and learn new ways of teaching. This short essay aims to explore the challenges posed to Portuguese higher education institutions and to analyze the challenges posed to evaluation models. To this end, the relevance of formative and summative assessment models in distance education is explored and the perception of teachers and students about the practices adopted in remote assessment is discussed. On the teachers' side, there is a high concern about adopting fraud-free models, and an excessive focus on the summative assessment component that in the distance learning model has less preponderance when compared to the gradual monitoring and assessment processes of the students, while on the students' side, problems arise regarding equipment to follow the teaching sessions and concerns about their privacy, particularly when intrusive IT solutions request the access to their cameras, audio, and desktop.
description: 8 pages, 10 references
Global denken – global handeln
Creators: name: Klauser, Hella
Publisher: name: Humboldt-Universität zu Berlin
Year: 2019
Subjects: subject: International Federation of Library Associations and Institutions
subject: Bibliothekspersonal
subject: Globalisierung
subject: Öffentliche Bibliothek
subject: Interessenvertretung
subject: 020 Bibliotheks- und Informationswissenschaften

description: „Du musst hier raus!“ lautet eines der Postkartenmotive der Kampagne des Arbeitsbereichs Internationale Kooperation im Kompetenznetzwerk für Bibliotheken (knb). Diese forsche Aufforderung soll zeigen, dass es für den Bibliotheksbereich stärker denn je ein „Muss“ ist, den Blick über die eigenen Grenzen hinaus auszuweiten und internationale Kontakte und Erfahrungen für die eigene Arbeit zu nutzen. Der internationale Bibliotheksverband IFLA begegnet der Erstellung von Zukunftskonzepten für den Bibliotheksbereich mit der globalen Vision für die Bibliotheken der Zukunft. Gesellschaftliche Herausforderungen, technische Entwicklungen, sich ändernde Anforderungen usw. können im internationalen Austausch deutlich besser gemeistert werden. Und wie das noch alles im Alltag stemmen, finanzieren, umsetzen? Die Internationalisierung der eigenen Arbeit ist machbar, sobald die Mauer im eigenen Kopf überwunden ist.
CDMS, Supersymmetry and Extra Dimensions
Creators: name: Baudis, Laura
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The CDMS experiment aims to directly detect massive, cold dark matter particles originating from the Milky Way halo. Charge and lattice excitations are detected after a particle scatters in a Ge or Si crystal kept at ~30 mK, allowing to separate nuclear recoils from the dominating electromagnetic background. The operation of 12 detectors in the Soudan mine for 75 live days in 2004 delivered no evidence for a signal, yielding stringent limits on dark matter candidates from supersymmetry and universal extra dimensions. Thirty Ge and Si detectors are presently installed in the Soudan cryostat, and operating at base temperature. The run scheduled to start in 2006 is expected to yield a one order of magnitude increase in dark matter sensitivity.
description: To be published in the proceedings of the 7th UCLA symposium on sources and detection of dark matter and dark energy in the universe, Marina del Rey, Feb 22-24, 2006
Field-induced confinement in (TMTSF)2ClO4 under accurately aligned magnetic fields
Creators: name: Joo, Nada
name: Auban-Senzier, Pascale
name: Pasquier, Claude. R
name: Yonezawa, Shingo
name: Higashinaka, Ryuji
name: Maeno, Yoshiteru
name: Haddad, Sonia
name: Charfi-Kaddour, Samia
name: Héritier, Michel
name: Bechgaard, Klaus
name: Jérome, Denis
Publisher: name: arXiv
Year: 2006
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We present transport measurements along the least conducting c direction of the organic superconductor (TMTSF)2ClO4, performed under an accurately aligned magnetic field in the low temperature regime. The experimental results reveal a two-dimensional confinement of the carriers in the (a,b) planes which is governed by the magnetic field component along the b' direction. This 2-D confinement is accompanied by a metal-insulator transition for the c axis resistivity. These data are supported by a quantum mechanical calculation of the transverse transport taking into account in self consistent treatment the effect of the field on the interplane Green function and on the intraplane scattering time.
Self-sustained spatiotemporal oscillations induced by membrane-bulk coupling
Creators: name: Gomez-Marin, A.
name: Garcia-Ojalvo, J.
name: Sancho, J. M.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We propose a novel mechanism leading to spatiotemporal oscillations in extended systems that does not rely on local bulk instabilities. Instead, oscillations arise from the interaction of two subsystems of different spatial dimensionality. Specifically, we show that coupling a passive diffusive bulk of dimension d with an excitable membrane of dimension d-1 produces a self-sustained oscillatory behavior. An analytical explanation of the phenomenon is provided for d=1. Moreover, in-phase and anti-phase synchronization of oscillations are found numerically in one and two dimensions. This novel dynamic instability could be used by biological systems such as cells, where the dynamics on the cellular membrane is necessarily different from that of the cytoplasmic bulk.
description: Accepted for publication in Physical Review Letters
Extended QED with CPT violation : clarifying some controversies
Creators: name: Bonneau, Guy
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We rediscuss the controversy on a possible Chern-Simons like term generated through radiative corrections in QED with a CPT violating term. We analyse some consequences of the division of the Lagrangian density between "free part" and "interaction part". We also emphasize the fact that any absence of an {\sl a priori} divergence should be explained by some symmetry or some non-renormalisation theorem and show that the so-called "unambiguous result" based upon "maximal SO(3) residual symmetry " does not offer a solution.
description: 11 pages, latex file, no figure
Stability of thermal structures with an internal heating source
Creators: name: Sanchez, Nestor
name: Lopez, Eugenio
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We study the thermal equilibrium and stability of isobaric, spherical structures having a radiation source located at its center. The thermal conduction coefficient, external heating and cooling rates are represented as power laws of the temperature. The internal heating decreases with distance from the source r approximately as exp(-tau)/(r**2), being tau the optical depth. We find that the influence of the radiation source is important only in the central region, but its effect is enough to make the system thermally unstable above a certain threshold central temperature. This threshold temperature decreases as the internal heating efficiency increases, but, otherwise, it does not depend on the structure size. Our results suggest that a solar-like star migrating into a diffuse interstellar region may destabilize the surrounding medium.
description: 16 pages including 4 figures. Accepted for publication in Revista Mexicana de Fisica
Spiral Structure Boosts Star Formation in Disk Galaxies
Creators: name: Yu, Si-Yue
name: Ho, Luis C.
name: Wang, Jing
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We investigate the impact of spiral structure on global star formation using a sample of 2226 nearby bright disk galaxies. Examining the relationship between spiral arms, star formation rate (SFR), and stellar mass, we find that arm strength correlates well with the variation of SFR as a function of stellar mass. Arms are stronger above the star-forming galaxy main sequence (MS) and weaker below it: arm strength increases with higher $\log\,({\rm SFR}/{\rm SFR}_{\rm MS})$, where ${\rm SFR}_{\rm MS}$ is the SFR along the MS. Likewise, stronger arms are associated with higher specific SFR. We confirm this trend using the optical colors of a larger sample of 4378 disk galaxies, whose position on the blue cloud also depends systematically on spiral arm strength. This link is independent of other galaxy structural parameters. For the subset of galaxies with cold gas measurements, arm strength positively correlates with HI and H$_2$ mass fraction, even after removing the mutual dependence on $\log\,({\rm SFR}/{\rm SFR}_{\rm MS})$, consistent with the notion that spiral arms are maintained by dynamical cooling provided by gas damping. For a given gas fraction, stronger arms lead to higher $\log\,({\rm SFR}/{\rm SFR}_{\rm MS})$, resulting in a trend of increasing arm strength with shorter gas depletion time. We suggest a physical picture in which the dissipation process provided by gas damping maintains spiral structure, which, in turn, boosts the star formation efficiency of the gas reservoir.
description: 11 pages, 7 figures, accepted for publication in ApJ
Optical forces arising from phase gradients
Creators: name: Roichman, Yohai
name: Sun, Bo
name: Roichman, Yael
name: Amato-Grill, Jesse
name: Grier, David G.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We demonstrate both theoretically and experimentally that gradients in the phase of a light field exert forces on illuminated objects, including forces transverse to the direction of propagation. This effect generalizes the notion of the photon orbital angular momentum carried by helical beams of light. We further demonstrate that these forces generally violate conservation of energy, and briefly discuss some ramifications of their non-conservativity.
description: 6 pages, 4 figures
Four point functions in CFT's with slightly broken higher spin symmetry
Creators: name: Silva, Joao A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We compute spinning four point functions in the quasi-fermionic three dimensional conformal field theory with slightly broken higher spin symmetry at finite t'Hooft coupling. More concretely, we obtain a formula for $\langle j_s j_{\tilde{0}} j_{\tilde{0}} j_{\tilde{0}} \rangle$, where $j_s$ is a higher spin current and $j_{\tilde{0}}$ is the scalar single trace operator. Our procedure consists in writing a plausible ansatz in Mellin space and using crossing, pseudo-conservation and Regge boundedness to fix all undetermined coefficients. Our method can potentially be generalised to compute all spinning four point functions in these theories.
description: Prepared for submission at JHEP
Evolutionary Quantum Dynamics of a Generic Universe
Creators: name: Battisti, Marco Valerio
name: Montani, Giovanni
Publisher: name: arXiv
Year: 2006
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The implications of an Evolutionary Quantum Gravity are addressed in view of formulating a new dark matter candidate. We consider a Schrödinger dynamics for the gravitational field associated to a generic cosmological model and then we solve the corresponding eigenvalues problem, inferring its phenomenological issue for the actual Universe. The spectrum of the super-Hamiltonian is determined including a free inflaton field, the ultrarelativistic thermal bath and a perfect gas into the dynamics. We show that, when a Planckian cut-off is imposed in the theory and the classical limit of the ground state is taken, then a dark matter contribution can not arise because its critical parameter $Ω_{dm}$ is negligible today when the appropriate cosmological implementation of the model is provided. Thus, we show that, from a phenomenological point of view, an Evolutionary Quantum Cosmology overlaps the Wheeler-DeWitt approach and therefore it can be inferred as appropriate to describe early stages of the Universe without significant traces on the later evolution. Finally, we provide indications that the horizon paradox can be solved in the Planck era by the morphology of the Universe wave function.
description: 7 pages, to appear on Phys. Lett. B
Collective excitations of superfluid Fermi gases near the transition temperature
Creators: name: Klimin, S. N.
name: Tempere, J.
name: Kurkjian, H.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: Studying the collective pairing phenomena in a two-component Fermi gas, we predict the appearance near the transition temperature $T_c$ of a well-resolved collective mode of quadratic dispersion. The mode is visible both above and below $T_c$ in the system's response to a driving pairing field. When approaching $T_c$ from below, the phononic and pair-breaking branches, characteristic of the zero temperature behavior, reduce to a very low energy-momentum region when the pair correlation length reaches its critical divergent behavior $ξ_{\rm pair}\propto|T_c-T|^{-1/2}$; elsewhere, they are replaced by the quadratically-dispersed pairing resonance, which thus acts as a precursor of the phase transition. In the strong-coupling and Bose-Einstein Condensate regime, this mode is a weakly-damped propagating mode associated to a Lorentzian resonance. Conversely, in the BCS limit it is a relaxation mode of pure imaginary eigenenergy. At large momenta, the resonance disappears when it is reabsorbed by the lower-edge of the pairing continuum. At intermediate temperatures between 0 and $T_c$, we unify the newly found collective phenomena near $T_c$ with the phononic and pair-breaking branches predicted from previous studies, and we exhaustively classify the roots of the analytically continued dispersion equation, and show that they provided a very good summary of the pair spectral functions.
description: 44 pages, 17 figures, accepted in Physical Review A (2021)
Status of SM calculations of b > s transitions
Creators: name: Hurth, Tobias
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We report recent progress in SM calculations of $b \to s$ transitions. We discuss the first NNLL prediction of the $\bar B \to X_s γ$ branching ratio, including important additional subtleties due to non-perturbative corrections and logarithmically-enhanced cut effects, and also recent results on the inclusive mode $\bar B \to X_s \ell^+ \ell^-$. Moreover, new results on the corresponding exclusive modes are reviewed. Finally, we comment on the present status of the so-called $B \to K π$ puzzle in hadronic $b \to s$ transitions
description: 10 pages, 6 figures, minor changes, published version
Quantum Gases in Optical Boxes
Creators: name: Navon, Nir
name: Smith, Robert P.
name: Hadzibabic, Zoran
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Atomic Physics (physics.atom-ph)
subject: Optics (physics.optics)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Advances in light shaping for optical trapping of neutral particles have led to the development of box traps for ultracold atoms and molecules. These traps have allowed the creation of homogeneous quantum gases and opened new possibilities for studies of many-body physics. They simplify the interpretation of experimental results, provide more direct connections with theory, and in some cases allow qualitatively new, hitherto impossible experiments. Here we review progress in this emerging field.
description: 11 pages, 6 figures. Comments welcome