cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Electromagnetic Casimir densities induced by a conducting cylindrical shell in the cosmic string spacetime
Creators: name: de Mello, E. R. Bezerra
name: Bezerra, V. B.
name: Saharian, A. A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We investigate the renormalized vacuum expectation values of the field square and the energy-momentum tensor for the electromagnetic field inside and outside of a conducting cylindrical shell in the cosmic string spacetime. By using the generalized Abel-Plana formula, the vacuum expectation values are presented in the form of the sum of boundary-free and boundary-induced parts. The asymptotic behavior of the vacuum expectation values of the field square, energy density and stresses are investigated in various limiting cases.
description: 14 pages, 2 figures, discussion and references added, accepted for publication in Phys. Lett. B
Influence of initial distributions on robust cooperation in evolutionary Prisoner's Dilemma
Creators: name: Chen, Xiaojie
name: Fu, Feng
name: Wang, Long
Publisher: name: arXiv
Year: 2007
Subjects: subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: We study the evolutionary Prisoner's Dilemma game on scale-free networks for different initial distributions. We consider three types of initial distributions for cooperators and defectors: initially random distribution with different frequencies of defectors; intentional organization with defectors initially occupying the most connected nodes with different fractions of defectors; intentional assignment for cooperators occupying the most connected nodes with different proportions of defectors at the beginning. It is shown that initial configurations for cooperators and defectors can influence the stationary level of cooperation and the evolution speed of cooperation. Organizations with the vertices with highest connectivity representing individuals cooperators could exhibit the most robust cooperation and drive evolutionary process to converge fastest to the high steady cooperation in the three situations of initial distributions. Otherwise, we determine the critical initial frequencies of defectors above which the extinction of cooperators occurs for the respective initial distributions, and find that the presence of network loops and clusters for cooperators can favor the emergence of cooperation.
description: Submitted to EPL
Dynamic hedging with non-martingale futures prices and time-varying volatilities
Creators: name: Marlowe, D. J.
Publisher: name: University of British Columbia
Year: 2009

description: Conventional hedging theory fails to take into account a number of stylized facts about exchange rate dynamics, most importantly the time-varying nature of volatility and the cointegration between spot and futures prices. In an effort to address this, recent studies have re-examined the hedging problem using both error correction models and GARCH error structures. These studies, however, rely on the questionable assumption of martingale futures prices. This implies that a strategy of holding futures contracts should never produce a non-zero expected profit, since the expectation of any subsequent futures price will always equal today's futures price. This paper derives a hedging model which does not impose this assumption, and uses out-of-sample testing to assess its performance relative to both the timevarying martingale model and other static models. Comparisons reveal that the martingale assumption is non-trivial, and that the hedge ratios derived under this assumption will differ greatly from those derived without it. Moreover, those derived without the martingale assumption can produce a higher expected utility for the hedger under certain circumstances.
Floquet Majorana bound states in voltage-biased Planar Josephson Junctions
Creators: name: Peng, Changnan
name: Haim, Arbel
name: Karzig, Torsten
name: Peng, Yang
name: Refael, Gil
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We study a planar Josephson junction under an applied DC voltage bias in the presence of an in-plane magnetic field. Upon tuning the bias voltage across the junction, $V_{\rm J}$, the two ends of the junction are shown to simultaneously host both $0$- and $π$-Majorana modes. These modes can be probed using either a Scanning-Tunneling-Microscopy measurement or through resonant Andreev tunneling from a lead coupled to the junction. While these modes are mostly bound to the junction's ends, they can hybridize with the bulk by absorbing or emitting photons. We analyze this process both numerically and analytically, demonstrating that it can become negligible under typical experimental conditions. Transport signatures of the $0$- and $π$-Majorana states are shown to be robust to moderate disorder.
description: 10 pages, 5 figures
Toward a Deterministic Model of Planetary Formation V. Accumulation Near the Ice Line
Creators: name: Ida, Shigeru
name: Lin, D. N. C.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We address two outstanding issues in the sequential accretion scenario for gas giant planet formation, the retention of dust grains in the presence of gas drag and that of cores despite type I migration. The efficiency of these processes is determined by the disk structure. Theoretical models suggest that planets form in protostellar disk regions with an inactive neutral ``dead zone'' near the mid plane, sandwiched together by partially ionized surface layers where magnetorotational instability is active. Due to a transition in the abundance of dust grains, the active layer's thickness decreases abruptly near the ice line. Over a range of modest accretion rates ($\sim 10^{-9}-10^{-8} M_\odot$ yr$^{-1}$), the change in the angular momentum transfer rate leads to local surface density and pressure distribution maxima near the ice line. The azimuthal velocity becomes super-Keplerian and the grains accumulate in this transition zone. This barrier locally retains protoplanetary cores and enhances the heavy element surface density to the critical value needed to initiate efficient gas accretion. It leads to a preferred location and epoch of gas giant formation. We simulate and reproduce the observed frequency and mass-period distribution of gas giants around solar type stars without having to greatly reduce the type I migration strength. The mass function of the short-period planets can be utilized to calibrate the efficiency of type I migration and to extrapolate the fraction of stars with habitable terrestrial planets.
description: 20 pages, 7 figures, accepted for publication in ApJ
Current Algebra of the Pure Spinor Superstring in AdS(5) x S(5)
Creators: name: Bianchi, M.
name: Kluson, J.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We perform a Hamiltonian analysis of the classical type IIB superstring on AdS(5) x S(5) in the pure spinor approach. Taking the spatial components of the left-invariant (super)currents and the pure spinor ghosts as canonical variables, we compute the classical graded Poisson brackets of the currents and ghosts and identify the first class constraints associated to the local SO(4,1) x SO(5) symmetry and the pure spinor condition. We then study the properties of the BRST generators and the Hamiltonian along the constraints. For a natural choice of the the Lagrange multipliers, we show equivalence of the canonical equations of motion with the covariant ones. Finally we briefly discuss the (non) local currents, including the ghost contribution, that generate the global PSU(2,2|4) symmetry and its Yangian extension in the present framework.
description: 26 pages, v2:corrected typos
Disc tearing: numerical investigation of warped disc instability
Creators: name: Raj, Anagha
name: Nixon, Chris
name: Dogan, Suzan
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We present numerical simulations of misaligned discs around a spinning black hole covering a range of parameters. Previous simulations have shown that discs that are strongly warped by a forced precession -- in this case the Lense-Thirring effect from the spinning black hole -- can break apart into discrete discs or rings that can behave quasi-independently for short timescales. With the simulations we present here, we confirm that thin and highly inclined discs are more susceptible to disc tearing than thicker or low inclination discs, and we show that lower values of the disc viscosity parameter lead to instability at lower warp amplitudes. This is consistent with detailed stability analysis of the warped disc equations. We find that the growth rates of the instability seen in the numerical simulations are similar across a broad range of parameters, and are of the same order as the predicted growth rates. However, we did not find the expected trend of growth rates with viscosity parameter. This may indicate that the growth rates are affected by numerical resolution, or that the wavelength of the fastest growing mode is a function of local disc parameters. Finally, we also find that disc tearing can occur for discs with a viscosity parameter that is higher than predicted by a local stability analysis of the warped disc equations. In this case, the instability manifests differently producing large changes in the disc tilt locally in the disc, rather than the large changes in disc twist that typically occur in lower viscosity discs.
description: 17 pages, 7 figures, accepted for publication in The Astrophysical Journal
A Magnetic Model of the Tetragonal-Orthorhombic Transition in the Cuprates
Creators: name: Chen, Fang
name: Hu, Jiangping
name: Kivelson, Steven
name: Brown, Stuart
Publisher: name: arXiv
Year: 2006
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: It is shown that a quasi two dimensional (layered) Heisenberg antiferromagnet with fully frustrated interplane couplings ({\it e.g.} on a body-centered tetragonal lattice) generically exhibits two thermal phase transitions with lowering temperature -- an upper transition at $T_{TO}$ (``order from disorder without order'') in which the lattice point-group symmetry is spontaneously broken, and a lower Néel transition at $T_{N}$ at which spin-rotation symmetry is broken. Although this is the same sequence of transitions observed in La$_2$CuO$_4$, in the Heisenberg model (without additional lattice degrees of freedom) $(T_{TO}-T_N) /T_N$ is much smaller than is observed. The model may apply to the bilayer cuprate La$_2$CaCuO$_6$, in which the transitions are nearly coincident.
description: 10 pages, 4 figures
Graviton emission from a Gauss-Bonnet brane
Creators: name: Konya, Kenichiro
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the emission of gravitons by a homogeneous brane with the Gauss-Bonnet term into an Anti de Sitter five dimensional bulk spacetime. It is found that the graviton emission depends on the curvature scale and the Gauss-Bonnnet coupling and that the amount of emission generally decreases. Therefore nucleosynthesis constraints are easier to satisfy by including the Gauss-Bonnet term.
description: 6 pages, 5 figures; (V2) published version
Unveiling the rarest morphologies of the LOFAR Two-metre Sky Survey radio source population with self-organised maps
Creators: name: Mostert, Rafaël I. J.
name: Duncan, Kenneth J.
name: Röttgering, Huub J. A.
name: Polsterer, Kai L.
name: Best, Philip N.
name: Brienza, Marisa
name: Brüggen, Marcus
name: Hardcastle, Martin J.
name: Jurlin, Nika
name: Mingo, Beatriz
name: Morganti, Raffaella
name: Shimwell, Tim
name: Smith, Dan
name: Williams, Wendy L.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The Low Frequency Array (LOFAR) Two-metre Sky Survey (LoTSS) is a low-frequency radio continuum survey of the Northern sky at an unparalleled resolution and sensitivity. In order to fully exploit this huge dataset and those produced by the Square Kilometre Array in the next decade, automated methods in machine learning and data-mining will be increasingly essential both for morphological classifications and for identifying optical counterparts to the radio sources. Using self-organising maps (SOMs), a form of unsupervised machine learning, we created a dimensionality reduction of the radio morphologies for the $\sim$25k extended radio continuum sources in the LoTSS first data release, which is only $\sim$2 percent of the final LoTSS survey. We made use of \textsc{PINK}, a code which extends the SOM algorithm with rotation and flipping invariance, increasing its suitability and effectiveness for training on astronomical sources. After training, the SOMs can be used for a wide range of science exploitation and we present an illustration of their potential by finding an arbitrary number of morphologically rare sources in our training data (424 square degrees) and subsequently in an area of the sky ($\sim$5300 square degrees) outside the training data. Objects found in this way span a wide range of morphological and physical categories: extended jets of radio active galactic nuclei, diffuse cluster haloes and relics, and nearby spiral galaxies. Finally, to enable accessible, interactive, and intuitive data exploration, we showcase the LOFAR-PyBDSF Visualisation Tool, which allows users to explore the LoTSS dataset through the trained SOMs.
description: 26 pages; accepted for publication in A&A
Theory of 2D superconductor with broken inversion symmetry
Creators: name: Dimitrova, Ol'ga
name: Feigel'man, M. V.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: A detailed theory of a phase diagram of a 2D surface superconductor in a parallel magnetic field is presented. A spin-orbital interaction of the Rashba type is known to produce at a high magnetic field $h$ (and in the absence of impurities) an inhomogeneous superconductive phase similar to the Larkin-Ovchinnikov-Fulde-Ferrel (LOFF) state with an order parameter $Δ(r) \propto \cos(Qr)$. We consider the case of a strong Rashba interaction with the spin-orbital splitting much larger than the superconductive gap $Δ$, and show that at low temperatures $T\leq 0.4 T_{c0}$ the LOFF-type state is separated from the usual homogeneous state by a first-order phase transition line. At higher temperatures another inhomogeneous state with $Δ(r) \propto \exp(i Qr)$ intervenes between the uniform BCS state and the LOFF-like state at $gμ_B h \approx 1.5 T_{c0}$. The modulation vector $Q$ in both phases is of the order of $gμ_B h/v_F$. The superfluid density $n_s^{yy}$ vanishes in the region around the second-order transition line between the BCS state and the new ``helical'' state. Non-magnetic impurities suppress both inhomogeneous states, and eliminate them completely at $T_{c0}τ\leq 0.11$. However, once an account is made of the next-order term over the small parameter $α/v_F \ll 1$, a relatively long-wave helical modulation with $Q \sim gμ_B hα/v_F^2$ is found to develop from the BCS state. This long-wave modulation is stable with respect to disorder. In addition, we predict that unusual vortex defects with a continuous core exist near the phase boundary between the helical and the LOFF-like states. In particular, in the LOFF-like state these defects may carry a half-integer flux.
description: 23 pages, 14 figures
The impact of financial attitudes and knowledge on financial management and satisfaction
Creators: name: Parotta, Jodi Lynne McFarlane
Publisher: name: University of British Columbia
Year: 2009

description: Using a model of financial management derived from the Deacon and Firebaugh (1988) Family Resource Management Model, this study examined the impact of financial attitudes and financial knowledge on financial management behaviours in a sample of recently married individuals. Attitudes and knowledge were examined both individually and conjointly. The moderating effect of financial knowledge on the relationship between financial attitudes and financial management behaviours was also investigated. In addition, the impact of financial management on satisfaction with financial status was assessed. In this assessment, two measures of financial management were compared on their relationship to satisfaction. The sample was recruited through a marriage preparation facility in Burnaby, British Columbia. Questionnaires were mailed to 565 past participants who took the course in 1992. The respondents were 194 recently married individuals, a response rate of 41%. When tested separately, both financial knowledge and financial attitudes were significantly related to financial management behaviours. When tested together, however, the effect financial knowledge had was lost, and only financial attitudes remained significantly related to financial management behaviours. Although it was expected that financial knowledge would moderate the relationship between financial attitudes and financial management behaviours, the results of this study did not provide support for this prediction. Results also showed that financial management behaviours were strongly related to satisfaction with financial status, and that the relationship between satisfaction with financial status and financial management behaviours was a function of the instrument used to measure the behaviours.
A general framework for multimode Gaussian quantum optics and photo-detection: application to Hong-Ou-Mandel interference with filtered heralded single photon sources
Creators: name: Thomas, Oliver F.
name: McCutcheon, Will
name: McCutcheon, Dara P. S.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The challenging requirements of large scale quantum information processing using parametric heralded single photon sources involves maximising the interference visibility whilst maintaining an acceptable photon generation rate. By developing a general theoretical framework that allows us to include large numbers of spatial and spectral modes together with linear and non-linear optical elements, we investigate the combined effects of spectral and photon number impurity on the measured Hong--Ou--Mandel interference visibility of parametric photon sources, considering both threshold and number resolving detectors, together with the effects of spectral filtering. We find that for any degree of spectral impurity, increasing the photon generation rate necessarily decreases the interference visibility, even when using number resolving detection. While tight spectral filtering can be used to enforce spectral purity and increased interference visibility at low powers, we find that the induced photon number impurity results in a decreasing interference visibility and heralding efficiency with pump power, while the maximum generation rate is also reduced.
description: 24 pages, 10 figures
Disc tearing: implications for black hole accretion and AGN variability
Creators: name: Raj, Anagha
name: Nixon, Chris
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Accretion discs around black holes power some of the most luminous objects in the Universe. Discs that are misaligned to the black hole spin can become warped over time by Lense-Thirring precession. Recent work has shown that strongly warped discs can become unstable, causing the disc to break into discrete rings producing a more dynamic and variable accretion flow. In a companion paper, we present numerical simulations of this instability and the resulting dynamics. In this paper, we discuss the implications of this dynamics for accreting black hole systems, with particular focus on the variability of Active Galactic Nuclei (AGN). We discuss the timescales on which variability might manifest, and the impact of the observer orientation with respect to the black hole spin axis. When the disc warp is unstable near the inner edge of the disc, we find quasi periodic behaviour of the inner disc which may explain the recent quasi periodic eruptions observed in, for example, the Seyfert 2 galaxy GSN 069 and in the galactic nucleus of RX J1301.9+2747. These eruptions are thought to be similar to the `heartbeat' modes observed in some X-ray binaries (e.g. GRS 1915+105 and IGR J17091-3624). When the instability manifests at larger radii in the disc, we find that the central accretion rate can vary on timescales that may be commensurate with, e.g., changing-look AGN. We therefore suggest that some of the variability properties of accreting black hole systems may be explained by the disc being significantly warped, leading to disc tearing.
description: 13 pages, 4 figures, accepted for publication in The Astrophysical Journal
TDCOSMO VI: Distance Measurements in Time-delay Cosmography under the Mass-sheet transformation
Creators: name: Chen, Geoff C. -F.
name: Fassnacht, Christopher D.
name: Suyu, Sherry H.
name: Yıldırım, Akın
name: Komatsu, Eiichiro
name: Bernal, Jose Luis
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Time-delay cosmography with gravitationally lensed quasars plays an important role in anchoring the absolute distance scale and hence measuring the Hubble constant, $H_{0}$, independent of traditional distance ladder methodology. A current potential limitation of time delay distance measurements is the "mass-sheet transformation" (MST) which leaves the lensed imaging unchanged but changes the distance measurements and the derived value of $H_0$. In this work we show that the standard method of addressing the MST in time delay cosmography, through a combination of high-resolution imaging and the measurement of the stellar velocity dispersion of the lensing galaxy, depends on the assumption that the ratio, $D_{\rm s}/D_{\rm ds}$, of angular diameter distances to the background quasar and between the lensing galaxy and the quasar can be constrained. This is typically achieved through the assumption of a particular cosmological model. Previous work (TDCOSMO IV) addressed the mass-sheet degeneracy and derived $H_{0}$ under the assumption of $Λ$CDM model. In this paper we show that the mass sheet degeneracy can be broken without relying on a specific cosmological model by combining lensing with relative distance indicators such as supernovae type Ia and baryon acoustic oscillations, which constrain the shape of the expansion history and hence $D_{\rm s}/D_{\rm ds}$. With this approach, we demonstrate that the mass-sheet degeneracy can be constrained in a cosmological-model-independent way, and hence model-independent distance measurements in time-delay cosmography under mass-sheet transformations can be obtained.
description: 11 pages, 8 figures
Detection of charge states of an InAs nanowire triple quantum dot with an integrated nanowire charge sensor
Creators: name: Li, Weijie
name: Mu, Jingwei
name: Huang, Shaoyun
name: Pan, Dong
name: Zhao, Jianhua
name: Xu, H. Q.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A linear triple quantum dot (TQD) integrated with a quantum dot (QD) charge sensor is realized. The TQD and the charge sensor are built from two adjacent InAs nanowires by fine finger gate technique. The charge state configurations of the nanowire TQD are studied by measurements of the direct transport signals of the TQD and by detection of the charge state transitions in the TQD via the nanowire QD sensor. Excellent agreements in the charge stability diagrams of the TQD obtained by the direct transport measurements and by the charge-state transition detection measurements are achieved. It is shown that the charge stability diagrams are featured by three groups of charge state transition lines of different slopes, corresponding to the changes in the electron occupation numbers of the three individual QDs in the TQD. It is also shown that the integrated nanowire QD sensor is highly sensitive and can detect the charge state transitions in the cases where the direct transport signals of the TQD are too weak to be measurable. Tuning to a regime, where all the three QDs in the TQD are close to be on resonance with the Fermi level of the source and drain reservoirs and co-existence of triple and quadruple points becomes possible, has also been demonstrated with the help of the charge sensor in the region where the direct transport signals of the TQD are hardly visible.
description: 17 pages, 5 figures
Manifestly Gauge Invariant QCD
Creators: name: Morris, Tim R.
name: Rosten, Oliver J.
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: Building on recent work in SU(N) Yang-Mills theory, we construct a manifestly gauge invariant exact renormalization group for QCD. A gauge invariant cutoff is constructed by embedding the physical gauge theory in a spontaneously broken SU(N|N) gauge theory, regularized by covariant higher derivatives. Intriguingly, the construction is most efficient if the number of flavours is a multiple of the number of colours. The formalism is illustrated with a very compact calculation of the one-loop beta function, achieving a manifestly universal result and without fixing the gauge.
description: 30 pages, 6 figures
How to enhance quantum generative adversarial learning of noisy information
Creators: name: Braccia, Paolo
name: Caruso, Filippo
name: Banchi, Leonardo
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: Quantum Machine Learning is where nowadays machine learning meets quantum information science. In order to implement this new paradigm for novel quantum technologies, we still need a much deeper understanding of its underlying mechanisms, before proposing new algorithms to feasibly address real problems. In this context, quantum generative adversarial learning is a promising strategy to use quantum devices for quantum estimation or generative machine learning tasks. However, the convergence behaviours of its training process, which is crucial for its practical implementation on quantum processors, have not been investigated in detail yet. Indeed here we show how different training problems may occur during the optimization process, such as the emergence of limit cycles. The latter may remarkably extend the convergence time in the scenario of mixed quantum states playing a crucial role in the already available noisy intermediate scale quantum devices. Then, we propose new strategies to achieve a faster convergence in any operating regime. Our results pave the way for new experimental demonstrations of such hybrid classical-quantum protocols allowing to evaluate the potential advantages over their classical counterparts.
description: 16 pages, 9 figures
Scaling laws of turbulent dynamos
Creators: name: Fauve, Stephan
name: Petrelis, Francois
Publisher: name: arXiv
Year: 2007
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We consider magnetic fields generated by homogeneous isotropic and parity invariant turbulent flows. We show that simple scaling laws for dynamo threshold, magnetic energy and Ohmic dissipation can be obtained depending on the value of the magnetic Prandtl number.
description: 6 pages, 1 figure
Anomalous Hall effect in weak-itinerant ferrimagnet FeCr$_2$Te$_4$
Creators: name: Liu, Yu
name: Tan, Hengxin
name: Hu, Zhixiang
name: Yan, Binghai
name: Petrovic, C.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We carried out a comprehensive study of electronic transport, thermal and thermodynamic properties in FeCr$_2$Te$_4$ single crystals. It exhibits bad-metallic behavior and anomalous Hall effect (AHE) below a weak-itinerant paramagentic-to-ferrimagnetic transition $T_c$ $\sim$ 123 K. The linear scaling between the anomalous Hall resistivity $ρ_{xy}$ and the longitudinal resistivity $ρ_{xx}$ implies that the AHE in FeCr$_2$Te$_4$ is most likely dominated by extrinsic skew-scattering mechanism rather than intrinsic KL or extrinsic side-jump mechanism, which is supported by our Berry phase calculations.
description: arXiv admin note: text overlap with arXiv:1811.07015
Governor Robert Dinwiddie and his political struggle to defend colonial Virginia
Creators: name: Gallagher, James R.
Publisher: name: Maryland Shared Open Access Repository
Year: 2009
Subjects: Robert Dinwiddie
Colonial Virginia
French and Indian War
American history

description: Governor Robert Dinwiddie struggled against many internal and external forces to perform his duties in securing the colony's borders against the intrusions of France and her Native American allies. Dinwiddie found himself bombarded by internal distractions and obstructions from other colonial governors, members of Virginia's House of Burgesses, the colonial militia, beside those advances against Virginia in the Ohio River Valley. He was able to overcome these issues and govern the colony at a time when the entire frontier was ablaze with war. Robert Dinwiddie's efforts as colonial governor during the French and Indian War proved his capabilities as a leader of men, and it was due much to these efforts that Virginia survived this conflict in the manner that it did.
Strong Admissibility for Abstract Dialectical Frameworks
Creators: name: Zafarghandi, Atefeh Keshavarzi
name: Verbrugge, Rineke
name: Verheij, Bart
Publisher: name: arXiv
Year: 2020
Subjects: subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Abstract dialectical frameworks (ADFs) have been introduced as a formalism for modeling and evaluating argumentation allowing general logical satisfaction conditions. Different criteria used to settle the acceptance of arguments are called semantics. Semantics of ADFs have so far mainly been defined based on the concept of admissibility. However, the notion of strongly admissible semantics studied for abstract argumentation frameworks has not yet been introduced for ADFs. In the current work we present the concept of strong admissibility of interpretations for ADFs. Further, we show that strongly admissible interpretations of ADFs form a lattice with the grounded interpretation as top element.
description: 9 pages, 3 Figures, SAC '21 conference: The 36th ACM/SIGAPP Symposium on Applied Computing
NOVEL METHODOLOGY FOR CALCIUM MEASUREMENTS IN CONSCIOUS MICE: AN APPLICATION TO ARTERIOLAR VASOMOTION
Creators: name: Zviman, Adam Lyle
Publisher: name: Digital Repository at the University of Maryland
Year: 2015
Subjects: subject: Physiology
subject: FOS: Biological sciences
subject: Cardiovascular
subject: Hypertension
subject: Physiology

description: We developed a method employing two-photon microscopy and genetically engineered ‘Ca2+- biosensor’ mice to measure Ca2+ signaling in arteries of conscious, head-fixed mice. Arterial blood pressure was measured simultaneously via implanted telemetric pressure transducers. These methods allowed, for the first time, the study of control of arterial [Ca2+], diameter, and blood pressure by sympathetic nerve activity (SNA) as it normally exists in conscious animals. We tested the hypothesis that arterial vasomotion, observed more frequently in conscious animals than in anesthetized animals, was generated by SNA that caused synchronous Ca2+-oscillations in smooth muscle. We also measured the changes in arterial [Ca2+] that occur during the time course of experimental hypertension. Pharmacological block of SNA and isoflurane anesthesia eliminated and attenuated, respectively, vasomotion and reduced arterial [Ca2+] (320 ± 48 nM to 241 ± 20 nM and 302 ± 48 nM). This method allows for longitudinal studies of important chronic vascular pathologies.
Low- and Intermediate-p$_T$ Di-hadron Distributions in Au+Au Collisions at $\sqrt{s_{NN}}=200$ GeV from STAR
Creators: name: Horner, M. J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We present a study of low- and intermediate-p$_T$ correlated azimuthal angular distributions in Au+Au collisions at $\sqrt{s_{NN}}=200 \rm{GeV}$ from STAR. The near-side associated yields in Au+Au collisions are found to be strongly enhanced, due to contributions from large $Δη$. The enhancement is reduced for high \pTtrig. We show a strong broadening and enhancement of the away-side yield. The evolution of the away-side shape may be explained as the sum of a broad structure from bulk response and a narrow peak from jet fragmentation.
description: 4 pages, 3 figures
Energy translation and Proper-Time Eigenstates
Creators: name: Wang, Zhi-Yong
name: Xiong, Cai-Dong
name: Zhang, Ai-Lin
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The usual quantum mechanics describes the mass eigenstates. To describe the proper-time eigenstates, a duality theory of the usual quantum mechanics was developed. The time interval is treated as an operator on an equal footing with the space interval, and the quantization of the space-time intervals between events is obtained. As a result, one can show that there exists a zero-point time interval.
description: 15 pages, No figure
Spreading height and critical conditions for the collapse of turbulent fountains in stratified media
Creators: name: Sarasua, L. G.
name: Freire, D.
name: Cabeza, C.
name: Marti, Arturo C.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: Axisymmetric fountains in stratified environments rise until reaching a maximum height, where the vertical momentum vanishes, and then falls and spread radially as an annular plume following a well-known top-hat profile. Here, firstly, we generalize the model of Morton et al. (Proc. R. Soc. Lond. A \textbf{234}, 1, 1956), in order to correctly determine the dependence of the maximum height and the spreading height with the parameters involved. We obtain the critical conditions for the collapse of the fountain, \textit i.e. when the jet falls up to the source level, and show that the spreading height must be expressed as a function of at least two parameters. To improve the quantitative agreement with the experiments we modify the criterion to take the mixing process in the down flow into account. Numerical simulations were implemented to estimate the parameter values that characterizes this merging. We show that our generalized model agrees very well with the experimental measurements.
description: 10 pages, 13 figures, several typos corrected
Regularization of conical singularities in warped six-dimensional compactifications
Creators: name: Papantonopoulos, Eleftherios
name: Papazoglou, Antonios
name: Zamarias, Vassilios
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the regularization of the codimension-2 singularities in six-dimensional Einstein-Maxwell axisymmetric models with warping. These singularities are replaced by codimension-1 branes of a ring form, situated around the axis of symmetry. We assume that there is a brane scalar field with Goldstone dynamics, which is known to generate a brane energy momentum tensor of a particular structure necessary for the above regularization to be successful. We study these compactifications in both a non-supersymmetric and a supersymmetric setting. We see that in the non-supersymmetric case, there is a restriction to the admissible warpings and furthermore to the quantum numbers of the bulk gauge field and the brane scalar field. On the contrary, in the supersymmetric case, the warping can be arbitrary.
description: 22 pages, 1 figure, comments added
title: Laramide Shortening in the Clark Mountain Thrust Complex: Reinterpretation of the Timing of the Winters Pass Thrust, Mojave Desert, SE California
Creators: name: Kombrink, Hayden
Publisher: name: University of Nevada, Las Vegas
publisherIdentifier: https://ror.org/0406gha72
publisherIdentifierScheme: ROR
Year: 2024

description: The transition to flat slab subduction, around ~90-80 Ma during the Laramide orogeny, marks a pivotal shift in the style of deformation for the North American Cordillera. Late Cretaceous deformation associated with the change in subduction angle is observed throughout the Mojave, paradoxically manifesting as extensional strain deforming the thickened crust formed during the Sevier orogeny. The Winters Pass thrust, located in the Mesquite Mountains of southeastern California, has long been regarded to be the southern continuation of the Wheeler Pass thrust of the NW Spring Mountains, 50 km to the north, and the northern continuation of the Pachalka thrust, 20 km to the south in the Clark Mountains. This study uses 40Ar 39Ar geochronology on synkinematic muscovite to provide direct geochronologic constraints on mylonitic deformation for the Winters Pass, Powerline Road and Pachalka thrusts. Structural data paired with kinematic and microstructural data from petrographic and SEM observations, and data collected with electron backscatter diffraction on recrystallized quartz allows for temperatures of deformation, the geometry of the thrust complex and transport direction of the upper-plate(s) to be determined. This study provides deformation timing constraints of ~73 Ma for the Winters Pass thrust, ~81 Ma for the Powerline Road thrust, and looser constraints on the Pachalka thrust of ~70-85 Ma. Structural data shows an overall NE-E direction of transport for the upper plate. These data suggest that these faults record a Laramide thrust complex with a backwards-breaking thrust sequence and are not correlative to any thrusts of the southern Sevier fold-thrust-belt in the Spring Mountains. We discuss possible drivers of contractional strain in the Mojave during this time and suggest that subduction of the conjugate Shatsky Rise paired with the proximity of the paleo rift-margin played a critical role in the unique style and age of deformation that is reported herein for this portion of the eastern Mojave Desert.
Quantizing Strings in de Sitter Space
Creators: name: Li, Miao
name: Song, Wei
name: Song, Yushu
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We quantize a string in the de Sitter background, and we find that the mass spectrum is modified by a term which is quadratic in oscillating numbers, and also proportional to the square of the Hubble constant.
description: 13 pages. Version published in JHEP
Measurement of biogenic hydrocarbon emissions from vegetation in the Lower Fraser Valley, British Columbia
Creators: name: Drewitt, Gordon
Publisher: name: University of British Columbia
Year: 2009

description: Biogenic volatile organic compounds (VOCs) are a diverse class of hydrocarbon released during the normal physiological processes of some species of vegetation. These substances can participate in many chemical reactions and in some cases have potential to promote the formation of ground level ozone. The Fraser Valley located in southwestern British Columbia occasionally experiences these air pollution episodes during the summer. In order to effectively reduce the frequency and magnitude of these episodes, it is important that we understand the relative role of biogenic hydrocarbons from the abundant vegetated surfaces in the region. The thesis presents the results of measurements conducted on four common tree species in the lower Fraser Valley using a branch enclosure apparatus. Hydrocarbon emission rates from Cottonwoods trees were approximately one hundred times greater than those from coniferous trees and were dominated by the compound isoprene. Monoterpenoid emissions from four tree species were highly variable in magnitude and demonstrated no statistically significant relationship with temperature. Comparison of the observed results with a simple model from the literature shows relatively close agreement in the case of isoprene but poor agreement with monoterpene emissions. Results of these branch enclosure studies were extrapolated to larger scales to yield an areal emission rate assuming reasonable biomass densities. Isoprene measurements in this study reveal an areal emission rate approximately twenty times that of the assumed value in current emissions inventories. This discrepancy could be quite significant considering its magnitude and the possible sensitivity of the chemical reactions that produce ground level ozone to changes in isoprene concentration.
The He-McKellar-Wilkens effect for spin one particles in non-commutative quantum mechanics
Creators: name: Dulat, Sayipjamal
name: Li, Kang
name: Wang, Jianhua
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mathematical Physics (math-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The He-McKellar-Wilkens(HMW) effect for spin one neutral particle in non-commutative quantum mechanics is studied. By solving the Kemmer like equations on non-commutative (NC) space and non-commutative phase space, we obtain topological He-McKellar-Wilkens phase on NC space and NC phase space respectively, where the additional terms related to the space-space and momentum-momentum non-commutativity are given explicitly.
description: 10 pages
OGLE-2007-BLG-224L: Confirmation of Terrestrial Parallax
Creators: name: Shan, Yutong
name: Yee, Jennifer C.
name: Bailey, Vanessa P.
name: Close, Laird M.
name: Hinz, Phil M.
name: Males, Jared R.
name: Morzinski, Katie M.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: We present limits on the lens flux of OGLE-2007-BLG-224 based on MagAO imaging taken seven years after the microlensing event. At the time of the observations, the lens should have been separated from the microlensing source by 292 mas. However, no new sources are detected with MagAO. We place an upper limit on the lens flux of $H>20.57$. This measurement supports the conclusion of Gould et al. (2009) that the lens in this event should be a brown dwarf. This is the first test of a prediction based on the terrestrial microlens parallax effect and the first AO confirmation of a sub-stellar/dark microlens.
description: Submitted to AAS Journals
Quantum critical phase transition between two topologically-ordered phases in the Ising toric code bilayer
Creators: name: Wiedmann, R.
name: Lenke, L.
name: Walther, M. R.
name: Mühlhauser, M.
name: Schmidt, K. P.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We demonstrate that two toric code layers on the square lattice coupled by an Ising interaction display two distinct phases with intrinsic topological order. The second-order quantum phase transition between the weakly-coupled $\mathbb{Z}_2\times\mathbb{Z}_2$ and the strongly-coupled $\mathbb{Z}_2$ topological order can be described by the condensation of bosonic quasiparticles from both sides and belongs to the 3d Ising$^*$ universality class. This can be shown by an exact duality transformation to the transverse-field Ising model on the square lattice, which builds on the existence of an extensive number of local $\mathbb{Z}_2$ conserved parities. These conserved quantities correspond to the product of two adjacent star operators on different layers. Notably, we show that the low-energy effective model derived about the limit of large Ising coupling is given by an effective single-layer toric code in terms of the conserved quantities of the Ising toric code bilayer. The two topological phases are further characterized by the topological entanglement entropy which serves as a non-local order parameter.
description: 6 pages, 3 figures
Aboriginal fishing rights, Sparrow, the law and social transformation : a case study of the Supreme Court of Canada decision in R. v. Sparrow
Creators: name: Sharma, Parnesh
Publisher: name: University of British Columbia
Year: 2009

description: Aboriginal rights, and aboriginal fishing rights in particular, are topics which elicit a variety of responses ranging from the positive to hostile. In British Columbia, fish is big business and it is the fourth largest industry in the province. The stakes are high and the positions of the various user groups and stakeholders are clearly demarcated. The fight over fish has pitted aboriginal groups against other aboriginal groups as well as against the federal government and its department of fisheries and oceans - however, the fight becomes vicious, underhanded, and mean spirited when the aboriginal groups are matched against the commercial industry. In an attempt to even the odds the aboriginal peoples have turned to the courts for recognition and protection of what they view as inherent rights - that is a right to fish arising out of the very nature of being an aboriginal person. Up until the Supreme Court of Canada decision in R. v. Sparrow aboriginal rights had been virtually ignored by both the courts and the state. However Sparrow changed all that and significantly altered the fight over fish. And that fight has become a virtual no-holds barred battle. The Sparrow decision remains to this day one of the most important Supreme Court decisions pertaining to aboriginal rights. This thesis is a case study of Sparrow - it will examine the decision from a perspective of whether subordinate or disadvantaged groups are able to use the law to advance their causes of social progress and equality. The thesis examines the status and nature of aboriginal fishing rights before and after the Sparrow decision. The thesis will examine whether the principles of the decision have been upheld or followed by the courts and the government of Canada. Data will consist of interviews with representatives of the key players in the fishing industry, namely, the Musqueam Indian Band, the Department of Fisheries and Oceans, and the commercial industry. In brief, the findings of my research do not bode well for the aboriginal peoples - the principles of the Sparrow decision have not been followed by the government of Canada and aboriginal fishing rights remain subject to arbitrary control. The thesis will examine why and how this happened.