Mass anomalous dimension in SU(2) with six fundamental fermions
Bursa, Francis; Del Debbio, Luigi; Keegan, Liam; Pica, Claudio; Pickup, Thomas
2010-01-01
We simulate SU(2) gauge theory with six massless fundamental Dirac fermions. We measure the running of the coupling and the mass in the Schroedinger Functional scheme. We observe very slow running of the coupling constant. We measure the mass anomalous dimension gamma, and find it is between 0.13.......135 and 1.03 in the range of couplings consistent with the existence of an IR fixed point.......We simulate SU(2) gauge theory with six massless fundamental Dirac fermions. We measure the running of the coupling and the mass in the Schroedinger Functional scheme. We observe very slow running of the coupling constant. We measure the mass anomalous dimension gamma, and find it is between 0...
Mass anomalous dimension of SU(2) with Nf=8 using the spectral density method
Suorsa, Joni M; Rantaharju, Jarno; Rantalaiho, Teemu; Rummukainen, Kari; Tuominen, Kimmo; Weir, David J
2015-01-01
SU(2) with Nf=8 is believed to have an infrared conformal fixed point. We use the spectral density method to evaluate the coupling constant dependence of the mass anomalous dimension for massless HEX smeared, clover improved Wilson fermions with Schr\\"odinger functional boundary conditions.
Anomalous scaling in an age-dependent branching model
Keller-Schmidt, Stephanie; Tugrul, Murat; Eguiluz, Victor M.; Hernandez-Garcia, Emilio; Klemm, Konstantin
2010-01-01
We introduce a one-parametric family of tree growth models, in which branching probabilities decrease with branch age $\\tau$ as $\\tau^{-\\alpha}$. Depending on the exponent $\\alpha$, the scaling of tree depth with tree size $n$ displays a transition between the logarithmic scaling of random trees and an algebraic growth. At the transition ($\\alpha=1$) tree depth grows as $(\\log n)^2$. This anomalous scaling is in good agreement with the trend observed in evolution of biological species, thus p...
Anomalous scaling in an age-dependent branching model
Keller-Schmidt, Stephanie; Tugrul, Murat; Eguíluz, Víctor M.; Hernández-García, Emilio; Klemm, Konstantin
2015-01-01
We introduce a one-parametric family of tree growth models, in which branching probabilities decrease with branch age $\\tau$ as $\\tau^{-\\alpha}$. Depending on the exponent $\\alpha$, the scaling of tree depth with tree size $n$ displays a transition between the logarithmic scaling of random trees and an algebraic growth. At the transition ($\\alpha=1$) tree depth grows as $(\\log n)^2$. This anomalous scaling is in good agreement with the trend observed in evolution of biological species, thus p...
Anomalous scaling in an age-dependent branching model.
Keller-Schmidt, Stephanie; Tuğrul, Murat; Eguíluz, Víctor M; Hernández-García, Emilio; Klemm, Konstantin
2015-02-01
We introduce a one-parametric family of tree growth models, in which branching probabilities decrease with branch age τ as τ(-α). Depending on the exponent α, the scaling of tree depth with tree size n displays a transition between the logarithmic scaling of random trees and an algebraic growth. At the transition (α=1) tree depth grows as (logn)(2). This anomalous scaling is in good agreement with the trend observed in evolution of biological species, thus providing a theoretical support for age-dependent speciation and associating it to the occurrence of a critical point. PMID:25768548
Quark mass anomalous dimension from the twisted mass Dirac operator spectrum
Cichy, Krzysztof [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Poznan Univ. (Poland). Faculty of Physics
2013-12-15
We investigate whether it is possible to extract the quark mass anomalous dimension and its scale dependence from the spectrum of the twisted mass Dirac operator in Lattice QCD. The answer to this question appears to be positive, provided that one goes to large enough eigenvalues, sufficiently above the non-perturbative regime. The obtained results are compared to continuum perturbation theory. By analyzing possible sources of systematic effects, we find the domain of applicability of the approach, extending from an energy scale of around 1.5 to 4 GeV. The lower limit is dictated by physics (non-perturbative effects at low energies), while the upper bound is set by the ultraviolet cut-off of present-day lattice simulations. We use gauge field configuration ensembles generated by the European Twisted Mass Collaboration (ETMC) with 2 flavours of dynamical twisted mass quarks, at 4 lattice spacings in the range between around 0.04 and 0.08 fm.
Anomalous scaling in an age-dependent branching model
Keller-Schmidt, Stephanie; Tugrul, Murat; Víctor M Eguíluz; Hernández-García, Emilio; Klemm, Konstantin
2015-01-01
© 2015 American Physical Society. We introduce a one-parametric family of tree growth models, in which branching probabilities decrease with branch age τ as τ-α. Depending on the exponent α, the scaling of tree depth with tree size n displays a transition between the logarithmic scaling of random trees and an algebraic growth. At the transition (α=1) tree depth grows as (logn)2. This anomalous scaling is in good agreement with the trend observed in evolution of biological species, thus provid...
On the anomalous mass defect of strange stars in the Field Correlator Method
Pereira, F. I. M.
2016-09-01
We investigate general aspects of the mass defects of strange stars in the context of the Field Correlator Method, without magnetic field. The main parameters of the model that enter the corresponding nonperturbative equation of state of the quark gluon plasma are the gluon condensate G2 and the large distance static Q Q bar potential V1. We calculate mass defects of stellar configurations in the central density range 11 mass defects are strongly dependent on the model parameters. For a large range of values of G2 and V1, we obtain anomalous mass defects with magnitudes around 1053 erg, of the same order of the observed energies of gamma-ray bursts and neutrino emissions in SN1987A, and of the theoretically predicted energies of the quark-novae explosions.
Propagators and Time-Dependent Diffusion Coefficients for Anomalous Diffusion
Wu, Jianrong; Berland, Keith M.
2008-01-01
Complex diffusive dynamics are often observed when one is investigating the mobility of macromolecules in living cells and other complex environments, yet the underlying physical or chemical causes of anomalous diffusion are often not fully understood and are thus a topic of ongoing research interest. Theoretical models capturing anomalous dynamics are widely used to analyze mobility data from fluorescence correlation spectroscopy and other experimental measurements, yet there is significant ...
Anomalous reaction-transport processes: the dynamics beyond the Mass Action Law
Campos Moreno, Daniel; Fedotov, Sergei; Méndez López, Vicenç
2008-01-01
In this paper we reconsider the Mass Action Law (MAL) for the anomalous reversible reaction $A\\rightleftarrows B$ with diffusion. We provide a mesoscopic description of this reaction when the transitions between two states $A$ and $B$ are governed by anomalous (heavy-tailed) waiting-time distributions. We derive the set of mesoscopic integro-differential equations for the mean densities of reacting and diffusing particles in both states. We show that the effective reaction rate memory kernels...
Lepton anomalous magnetic moments from twisted mass fermions
Burger, Florian; Jansen, Karl; Petschlies, Marcus
2014-01-01
We present our results for the leading-order hadronic quark-connected contributions to the electron, the muon, and the tau anomalous magnetic moments obtained with four dynamical quarks. Performing the continuum limit and an analysis of systematic effects, full agreement with phenomenological results is found. To estimate the impact of omitting the quark-disconnected contributions to the hadronic vacuum polarisation we investigate them on one of the four-flavour ensembles. Additionally, the light quark contributions on the four-flavour sea are compared to the values obtained for $N_f=2$ physically light quarks. In the latter case different methods to fit the hadronic vacuum polarisation function are tested.
Neutrino masses, anomalous U(1) gauge symmetry and doublet-triplet splitting
We propose an attractive scenario of grand unified theories in which doublet-triplet splitting is naturally realized in SO(10) unification using the Dimopoulos-Wilczek mechanism. The anomalous U(1)A gauge symmetry plays an essential role in the double-triplet splitting mechanism. It is interesting that the anomalous U(1)A charges determine the unification scale and mass spectrum of additional particles, as well as the order of the Yukawa couplings of quarks and leptons. For the neutrino sector, bi-maximal mixing angles are naturally obtained, and proton decay via dimension 5 operators is suppressed. It is suggestive that the anomalous U(1)A gauge symmetry motivated by superstring theory effectively solves the two biggest problems in grand unified theories, the fermion mass hierarchy problem and doublet-triplet splitting problem. (author)
Dependence of (anomalous) fading of infra-red stimulated luminescence on trap occupancy in feldspars
Morthekai, P.; Jain, Mayank; Gach, Grzegorz; Elema, Dennis Ringkjøbing; Prip, Henrik
2013-01-01
after 90Sr/90Y beta particle irradiation (3.5–15%/decade) for all the measured feldspar mineral specimens. Similarly, the fading rates after x-rays of 50 kV and 10 kV fall in between those of beta particle and proton irradiations. Our results suggest that rate of anomalous fading in feldspars depends on......Dose dependency of anomalous fading of infra-red stimulated luminescence (IRSL) from feldspars has been investigated using radiations of different ionisation qualities. The rate of fading of the IRSL signal after proton irradiation (9.4–30%/decade) is on an average almost twice compared to that...
Anomalous Temperature Dependence of Vibrational Lifetimes in Water and Ice
Woutersen, Sander; Emmerichs, Uli; Nienhuys, Han-Kwang; Bakker, Huib J.
1998-08-01
We have used femtosecond two-color midinfrared spectroscopy to determine the temperature dependence of the OH-stretching lifetime in dilute HDO:D2O solution, both in the liquid and solid (ice Ih) state. Like many other properties of water, the vibrational lifetime shows a remarkable temperature dependence: In liquid water the vibrational relaxation of the OH-stretching mode is twice as slow as in ice, and becomes even slower with increasing temperature.
Mass anomalous dimension of SU(2) with N_{f}=8 using the spectral density method
Suorsa, Joni M.; Leino, Viljami; Rantaharju, Jarno; Rantalaiho, Teemu; Rummukainen, Kari; Tuominen, Kimmo; Weir, David J.
2015-01-01
SU(2) with Nf=8 is believed to have an infrared conformal fixed point. We use the spectral density method to evaluate the coupling constant dependence of the mass anomalous dimension for massless HEX smeared, clover improved Wilson fermions with Schr\\"odinger functional boundary conditions....
Anomalous temperature dependence of excitation transfer between quantum dots
Král, Karel; Menšík, Miroslav
2015-01-01
Roč. 7, č. 4 (2015), 325-330. ISSN 2164-6627 R&D Projects: GA MŠk(CZ) LD14011; GA MŠk LH12236; GA MŠk LH12186 Institutional support: RVO:68378271 ; RVO:61389013 Keywords : excitation transfer * quantum dots * temperature dependence * electron-phonon interaction Subject RIV: BM - Solid Matter Physics ; Magnetism
Anomalous temperature dependence of the fluorescence lifetime of phycobiliproteins
Using a single photon counting technique we have investigated fluorescence decay spectra of phycobiliproteins with picosecond time resolution. The studies were performed in a wide range of temperatures—from 4 to 300 K. Comparing the fluorescence decay kinetics of samples rapidly frozen in liquid nitrogen with samples that were frozen slowly revealed that the temperature-dependent changes of phycobiliproteins fluorescence lifetime reflect the presence of three different stages, with a phase transition between 273 and 263 K that strongly depends on the rate of freezing. When the temperature decreases from 300 to 273 K, the fluorescence lifetime increases from 1.6 to 1.8 ns. In the region from 273 to 263 K we observed a decrease of the fluorescence lifetime, which strongly depends on the freezing rate: a slight decrease at high freezing rate and a drop down to 200 ps lifetime at slow freezing rate. In the low-temperature regime from 263 to 4 K a linear increase in the fluorescence lifetime was observed for all samples. It was found that the strong temperature dependence of the phycobiliprotein fluorescence, especially in the range between 263 and 273 K, is due to the interaction of the solvent with the chromophore bound to the protein. This feature is explained by a photoisomerization of the phycobiliproteins into a quenching form which is naturally prevented by the protein environment. The formation of ice microcrystals at low freezing rate eliminates this ‘protective’ effect of the protein environment. (letter)
Anomalous temperature dependence of the fluorescence lifetime of phycobiliproteins
Maksimov, E. G.; Schmitt, F.-J.; Hätti, P.; Klementiev, K. E.; Paschenko, V. Z.; Renger, G.; Rubin, A. B.
2013-05-01
Using a single photon counting technique we have investigated fluorescence decay spectra of phycobiliproteins with picosecond time resolution. The studies were performed in a wide range of temperatures—from 4 to 300 K. Comparing the fluorescence decay kinetics of samples rapidly frozen in liquid nitrogen with samples that were frozen slowly revealed that the temperature-dependent changes of phycobiliproteins fluorescence lifetime reflect the presence of three different stages, with a phase transition between 273 and 263 K that strongly depends on the rate of freezing. When the temperature decreases from 300 to 273 K, the fluorescence lifetime increases from 1.6 to 1.8 ns. In the region from 273 to 263 K we observed a decrease of the fluorescence lifetime, which strongly depends on the freezing rate: a slight decrease at high freezing rate and a drop down to 200 ps lifetime at slow freezing rate. In the low-temperature regime from 263 to 4 K a linear increase in the fluorescence lifetime was observed for all samples. It was found that the strong temperature dependence of the phycobiliprotein fluorescence, especially in the range between 263 and 273 K, is due to the interaction of the solvent with the chromophore bound to the protein. This feature is explained by a photoisomerization of the phycobiliproteins into a quenching form which is naturally prevented by the protein environment. The formation of ice microcrystals at low freezing rate eliminates this ‘protective’ effect of the protein environment.
Frequency dependence of anomalous transport in field theory and holography⋆,⋆⋆
Megías Eugenio
2014-01-01
Full Text Available We study the frequency dependence of anomalous transport coefficients for a relativistic gas of free chiral fermions and for a strongly coupled conformal field theory with holographic dual. We perform the computation by using the Kubo formulae for- malism, and compare with a hydrodynamic calculation of two point functions. Some implications for heavy ion physics are discussed.
Pauli equation with position-dependent mass
The motion of electron with position-dependent mass is studied. The number of zero modes for an electron with position dependent mass in magnetic field is found as well. This result is the generation of Aharonov-Casher theorem obtained for constant mass for the case of position-dependent mass
Origin of the anomalous temperature dependence of coercivity in soft ferromagnets
We report on the origin of the anomalous temperature dependence of coercivity observed in some soft ferromagnets by studying the magnetic and electronic properties of FeZr films doped using ion implantation by H, He, B, C, and N. The anomalous increase of the coercivity with temperature was observed only in the C- and B-doped samples. Using x-ray photoelectron spectroscopy, we show that the anomalous behavior of the coercivity coincides with the occurrence of an electron charge transfer for those implanted samples. The origin of the anomaly is discussed in terms of (i) magnetic softness, (ii) nature of the Fe-C and -B covalent bonds, and (iii) large charge transfer
Polarization dependent diffraction anomalous fine structure of rutile TiO2 001 and 111 reflections
Energy and polarization dependent Diffraction Anomalous Fine Structure (DAFS) also known as Anisotropic Anomalous Scattering (AAS) can be employed in addition to X-ray Absorption Fine Structure (XAFS) to study electronic transitions from core states to unoccupied states. Here, we present results from resonant X-ray diffraction experiments on TiO2 rutile, space group (136) P42/mnm. For this model structure, site symmetry information was extracted from determination of the structure factor tensor by refining elements of Ti atomic scattering factor tensors. Influences of oxygen vacancies on the anomalous scattering contributions have been studied on a series of rutile wafers of different oxygen concentration. Samples investigated were 10 x 10 x 1 mm3 single crystal wafers and experiments were carried out at DESY/HASYLAB beamlines C and E2 using a Si(111) double crystal monochromator in the vicinity of the Ti-K absorption edge. Considered reflections include the 'forbidden' 001 and allowed 111 reflection.
Anomalous Temperature Dependence of Magnetic Moment in Monodisperse Antiferromagnetic Nanoparticles
Gillaspie, Dane; Gu, B.; Wang, W.; Shen, J.
2005-03-01
1 Condensed Matter Sciences Division, Oak Ridge National Laboratory*, TN 37831 2 Department of Physics and Astronomy, The University of Tennessee, TN 37996 3 Environmental Sciences Division, Oak Ridge National Laboratory*, TN 37831 Recent experiments [1] and theory [2] from AFM nanoparticles showed that they exhibit sizable net magnetization, which increases with increasing temperature. In order to further understand such peculiar temperature dependence, we have measured the magnetic properties of monodisperse hematite (α-Fe2O3) nanoparticles, grown using a microemulsion precipitation technique, which minimizes the impact of the particle moment distribution on the measured properties of the samples. Our measured results indicate that the net magnetization of these nanoparticles, when small, indeed increases linearly with increasing temperature. This is in sharp contrast to the bulk-like behavior of α-Fe2O3, which was observed in particles with size larger than 120 nm. [1] M. Seehra et al, Phys. Rev. B 61, 3513 (2000) [2] S. Mørup, C. Frandsen, Phys. Rev. Lett. 92, 217201 (2004) *Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under contract DE-AC05-00OR22725
Capilla, J. E.; Sanchez Fuster, I.; Sanchez Barrero, L.
2012-12-01
The limitations of the classical Advection-Dispersion Equation (ADE) approach to model mass transport remain a subject of research. The term anomalous transport is usually applied when the ADE fails to reproduce real field or lab experiments tracer tests data. Some authors address this limitation using high-resolution heterogeneous hydraulic conductivity (K) fields. Besides, the non-Fickian behavior of transport is another issue addressed. However, the effects of the spatial variability of dispersivity, and the influence of the model support scale on this property, have been rarely studied. The lack of experimental knowledge on the dispersivity behavior leads to model this basic parameter as an averaged calibrated parameter highly dependent on the model discretization size. In order to study the local behavior of the dispersivity a porous medium tank was designed and built at the Technical University of Valencia (Spain). This paper presents new results and conclusions obtained from the experiments conducted in this lab prototype. The steady flow through the porous medium tank lab is quasi-2D, and the K field imitates the patterns of spatial variability found in a real and highly heterogeneous formation (MADE2 site). The tracer tests are run using a conservative dye tracer and the tank is monitored by a grid of pressure transducers and taking digital images that are processed to map the evolution of solute concentrations in the tank. The set of exhaustive head and concentration data is used to compute detail local information of the effective dispersivity field at different time steps, and at different support scales. The analysis of results shows that the dispersivity field displays patterns of spatial variability related with the physical nature of the local material and also with the local evolution of concentrations at every grid block. We have found that the anomalous transport behavior observed in the lab tank can be accurately modeled using the classical ADE
The origin of compact galaxies with anomalously high black hole masses.
Barber, C.; Schaye, J.; Bower, R. G.; Crain, R. A.; Schaller, M.; Theuns, T.
2016-01-01
Observations of local galaxies harbouring supermassive black holes (BH) of anomalously high mass, MBH, relative to their stellar mass, M*, appear to be at odds with simple models of the co-evolution between galaxies and their central BHs. We study the origin of such outliers in a Λ cold dark matter context using the EAGLE cosmological, hydrodynamical simulation. We find 15 ‘MBH(M*)-outlier' galaxies, defined as having MBH more than 1.5 dex above the median MBH(M*) relation in the simulation, ...
Constraint on the QED vertex from the mass anomalous dimension γm = 1
We discuss the structure of the non-perturbative fermion-boson vertex in quenched QED. We show that it is possible to construct a vertex which not only ensures that the fermion propagator is multiplicatively renormalizable, obeys the appropriate Ward-Takahashi identity, reproduces perturbation theory for weak couplings and guarantees that the critical coupling at which the mass is dynamically generated is gauge independent but also makes sure that the value for the anomalous dimension for the mass function is strictly 1, as Holdom and Mahanta have proposed. (author). 8 refs
The origin of compact galaxies with anomalously high black hole masses.
Barber, C; Schaye, J.; Bower, R. G.; Crain, R.A.; Schaller, M.; Theuns, T.
2016-01-01
Observations of local galaxies harbouring supermassive black holes (BHs) of anomalously high mass, M_BH, relative to their stellar mass, M_star, appear to be at odds with simple models of the co-evolution between galaxies and their central BHs. We study the origin of such outliers in a Lambda cold dark matter context using the EAGLE cosmological, hydrodynamical simulation. We find 15 'M_BH(M_star)-outlier' galaxies, defined as having M_BH more than 1.5 dex above the median M_BH(M_star) relati...
Dependence of (anomalous) fading of infra-red stimulated luminescence on trap occupancy in feldspars
Dose dependency of anomalous fading of infra-red stimulated luminescence (IRSL) from feldspars has been investigated using radiations of different ionisation qualities. The rate of fading of the IRSL signal after proton irradiation (9.4–30%/decade) is on an average almost twice compared to that after 90Sr/90Y beta particle irradiation (3.5–15%/decade) for all the measured feldspar mineral specimens. Similarly, the fading rates after x-rays of 50 kV and 10 kV fall in between those of beta particle and proton irradiations. Our results suggest that rate of anomalous fading in feldspars depends on the number density of the trapped charge carriers. These results support the hypothesis that anomalous fading occurs across randomly distributed donor-acceptor distances as opposed to pairs with a fixed distance. -- Highlights: • Proton irradiated IRSL in feldspar fades twice as fast as that of beta particles. • Systematic increase of fading rates with beta particles, x-rays and proton. • Observation suggests the dose rate is dose dependent i.e., burial age. • Tunnelling model with randomly distributed sites is favoured by the results
Anomalous temperature dependency of the Anderson-Grüneisen parameters in high ionic conductors
The Anderson-Grüneisen (AG) parameter carries information on the anharmonicity of the atomic vibrations of the materials. Therefore, its study is expected to provide useful insights to understand the ion transport properties in solids. However, few attentions on the AG parameter of ionic conductors have been paid till now. In the present paper, a comparative study on the temperature dependence of the AG parameter in superionic materials and other crystals is presented. It is shown that the AG parameter of superionic materials exhibit anomalously large temperature dependencies. The relations of this finding with the material properties of ionic conductors are briefly discussed.
Anomalous Fano resonance of massive Dirac particle through a time-dependent barrier
Zhang, Cunxi; Liu, Jie; Fu, Libin
2015-06-01
As is well known Fano resonance arises from the interference between a localized state and a continuum state. Using the standard Floquet theory and the scattering matrix method, we study theoretically the massive Dirac particle transmission over a quantum barrier with an oscillating field. It is found that the massive relativistic particles can generate not only normal Fano resonance in the transmission due to the interference between a localized state (bound state) and the continuum state, but also anomalous Fano resonance due to the interference between a delocalized state (extended state) and the continuum state. The dependence of line shapes on driving parameters for these two kinds of Fano resonances is quite different. For normal Fano resonance the asymmetry parameter is approximately proportional to a power law of the amplitude of the oscillating field, while for the anomalous Fano resonance the asymmetry parameters change slightly with different oscillation amplitudes. In practice, the anomalous Fano resonance can be identified by observing asymmetry parameters in experiment.
Higgs mass and muon anomalous magnetic moment in the U(1) extended MSSM
Endo, Motoi; Iwamoto, Sho; Nakayama, Kazunori; Yokozaki, Norimi
2011-01-01
We study phenomenological aspects of the MSSM with extra U(1) gauge symmetry. We find that the lightest Higgs boson mass can be increased up to 125GeV without introducing a large SUSY scale or large A-terms, in the frameworks of the CMSSM and gauge mediated SUSY breaking (GMSB) models. This scenario can simultaneously explain the discrepancy of the muon anomalous magnetic moment (muon g-2) at the 1 sigma / 2 sigma level for U(1)-extended CMSSM / GMSB models. In the CMSSM case, the dark matter abundance can also be explained.
Anomalous coupling, top-mass and parton-shower effects in W + W - production
Bellm, J.; Gieseke, S.; Greiner, N.; Heinrich, G.; Plätzer, S.; Reuschle, C.; von Soden-Fraunhofen, J. F.
2016-05-01
We calculate the process ppto {W}+{W}-to {e}+{ν}_e{μ}-{overline{ν}}_{μ } at NLO QCD, including also effective field theory (EFT) operators mediating the ggW + W - interaction, which first occur at dimension eight. We further combine the NLO and EFT matrix elements produced by G oS am with the H erwig7/M atchbox framework, which offers the possibility to study the impact of a parton shower. We assess the effects of the anomalous couplings by comparing them to top-mass effects as well as uncertainties related to variations of the renormalisation, factorisation and hard shower scales.
Migliori, A.; Maxton, P.M.; Clogston, A.M.; Zirngiebl, E.; Lowe, M.
1988-12-15
We measured the temperature dependence of the intensity of the two lowest Raman modes in single crystals of l-alanine. The sum of the intensities obeys Maxwell-Boltzman statistics accurately from 20 to 340 K but the intensities of the individual lines are anomalous. This behavior is explained by assuming that both lines share the same degrees of freedom but that a mode instability is triggered abruptly at an occupation of seven quanta. This instability, which has an activation energy of 500 K, is observed at temperatures as low as 20 K, possibly indicating the existence of dynamic localization of vibrational energy.
Gao, Xing; Shi, Zhijun; Lau, Andrew; Liu, Changqin; Yang, Guang; Silberschmidt, Vadim V
2016-05-01
This study is focused on anomalous strain-rate-dependent behaviour of bacterial cellulose (BC) hydrogel that can be strain-rate insensitive, hardening, softening, or strain-rate insensitive in various ranges of strain rate. BC hydrogel consists of randomly distributed nanofibres and a large content of free water; thanks to its ideal biocompatibility, it is suitable for biomedical applications. Motivated by its potential applications in complex loading conditions of body environment, its time-dependent behaviour was studied by means of in-aqua uniaxial tension tests at constant temperature of 37 °C at various strain rates ranging from 0.000 1s(-1) to 0.3s(-1). Experimental results reflect anomalous strain-rate-dependent behaviour that was not documented before. Micro-morphological observations allowed identification of deformation mechanisms at low and high strain rates in relation to microstructural changes. Unlike strain-rate softening behaviours in other materials, reorientation of nanofibres and kinematics of free-water flow dominate the softening behaviour of BC hydrogel at high strain rates. PMID:26952406
Anomalous roughness of turbulent interfaces with system size dependent local roughness exponent
In a system far from equilibrium the system size can play the role of control parameter that governs the spatiotemporal dynamics of the system. Accordingly, the kinetic roughness of interfaces in systems far from equilibrium may depend on the system size. To get an insight into this problem, we performed a detailed study of rough interfaces formed in paper combustion experiments. Using paper sheets of different width λ, we found that the turbulent flame fronts display anomalous multi-scaling characterized by non-universal global roughness exponent α and by the system size dependent spectrum of local roughness exponents, ζq(λ)=ζ1(1)q-ωλφq=0.93q-0.15. The structure factor of turbulent flame fronts also exhibits unconventional scaling dependence on λ. These results are expected to apply to a broad range of far from equilibrium systems when the kinetic energy fluctuations exceed a certain critical value.
Quanli; Dong; Dawei; Yuan; Shoujun; Wang; Xun; Liu; Yutong; Li; Xiaoxuan; Lin; Huigang; Wei; Jiayong; Zhong; Shaoen; Jiang; Yongkun; Ding; Bobin; Jiang; Kai; Du; Yongjian; Tang; Mingyang; Yu; Xiantu; He; Neng; Hua; Zhanfeng; Qiao; Kuixi; Huang; Ming; Chen; Jianqiang; Zhu; Gang; Zhao; Zhengming; Sheng; Jie; Zhang
2013-01-01
The driving mechanism of solar flares and coronal mass ejections is a topic of ongoing debate, apart from the consensus that magnetic reconnection plays a key role during the impulsive process. While present solar research mostly depends on observations and theoretical models, laboratory experiments based on high-energy density facilities provide the third method for quantitatively comparing astrophysical observations and models with data achieved in experimental settings.In this article, we show laboratory modeling of solar flares and coronal mass ejections by constructing the magnetic reconnection system with two mutually approaching laser-produced plasmas circumfused of self-generated megagauss magnetic fields. Due to the Euler similarity between the laboratory and solar plasma systems, the present experiments demonstrate the morphological reproduction of flares and coronal mass ejections in solar observations in a scaled sense,and confirm the theory and model predictions about the current-sheet-born anomalous plasmoid as the initial stage of coronal mass ejections, and the behavior of moving-away plasmoid stretching the primary reconnected field lines into a secondary current sheet conjoined with two bright ridges identified as solar flares.
Anomalous dependence of population growth on the birth rate in the plant-herbivore system
Cui, Xue M. [Chungbuk National University, Cheongju (Korea, Republic of); Yanbian University, Yanji (China); Han, Seung K.; Chung, Jean S. [Chungbuk National University, Cheongju (Korea, Republic of)
2010-12-15
We performed a simulation of the two-species plant-herbivore system by using the agent-based NetLogo program and constructed a dynamic model of populations consistent with the simulation results. The dynamic model is a three-dimensional system including the mean energy of the herbivore in addition to two variables denoting the populations of plants and herbivores. A steady-state analysis of the dynamic model shows that the dependence of the herbivore population on the birth and the death rates observed from the agent model is consistent with the prediction of the dynamic model. Especially, the anomalous dependence of the herbivore population on the birth rate, where the population decreases with the birth rate for small death rate, is consistently explained by a phase plane analysis of the dynamic model.
Anomalous strain rate dependence of the flow stress in polycrystalline TiAl intermetallic compounds
Plastic deformation of TiAl and TiAl-V intermetallic compounds have been studied by compression experiment at various temperatures and strain rates. The results showed that plastic deformation was controlled primarily by Peierls Nabarro, cross slip and creep mechanisms of dislocations in distinct temperature ranges. In TiAl-V alloy deformed at range of 600-700K, anomalous strain rate dependence of flow stress was observed, i.e., the larger the plastic strain was, the more negative the dependence. A possible mechanism of the anomaly could be interpreted by thermal activation of dislocation cross slipping. The effects of temperature and strain rate on work-hardening exponent were also studied and discussed in the present paper
The temperature dependent anomalous Hall effect in La-Ca-Mn-O films
The colossal magnetoresistance of La1-xCaxMnO3 has been reported in many experiments. The authors present their study of the anomalous Hall effect in epitaxial La0.67Ca0.33MnO3 thin films. They have measured the temperature dependence of resistivity, magnetization and AHE coefficients between 300K and 5K for the samples grown on different substrates. From these studies, the relation between the resistivity and AHE coefficient as well as the temperature dependence of AHE coefficient are explored. The results show that the direction of AHE is reversed below approximately 100K. This sign reversal is discussed in term of the change of band structure and the co-existence of hole-like and electron-like conduction
Gopalswamy, Nat; Akiyama, Sachiko; Yashiro, Seiji; Xie, Hong; Makela, Pertti; Michalek, Grzegorz
2014-01-01
The familiar correlation between the speed and angular width of coronal mass ejections (CMEs) is also found in solar cycle 24, but the regression line has a larger slope: for a given CME speed, cycle 24 CMEs are significantly wider than those in cycle 23. The slope change indicates a significant change in the physical state of the heliosphere, due to the weak solar activity. The total pressure in the heliosphere (magnetic + plasma) is reduced by approximately 40%, which leads to the anomalous expansion of CMEs explaining the increased slope. The excess CME expansion contributes to the diminished effectiveness of CMEs in producing magnetic storms during cycle 24, both because the magnetic content of the CMEs is diluted and also because of the weaker ambient fields. The reduced magnetic field in the heliosphere may contribute to the lack of solar energetic particles accelerated to very high energies during this cycle.
The temperature dependence of the magneto-conductance (MC) in organic electron donor-acceptor hybrid and layer heterojunction diodes was studied. The MC value increased with temperature in layer heterojunction and in 10 wt. % hybrid devices. An anomalous decrease of the MC with temperature was observed in 25 wt. %–50 wt. % hybrid devices. Further increasing donor concentration to 75 wt. %, the MC again increased with temperature. The endothermic exciplex-exciton energy transfer and the change in electroplex/exciton ratio caused by change in charge transport with temperature may account for these phenomena. Comparative studies of the temperature evolutions of the IV curves and the electroluminescence and photoluminescence spectra back our hypothesis
The origin of compact galaxies with anomalously high black hole masses
Barber, Christopher; Bower, Richard G; Crain, Robert A; Schaller, Matthieu; Theuns, Tom
2016-01-01
Observations of local galaxies harbouring supermassive black holes (BH) of anomalously high mass, M_BH, relative to their stellar mass, M_star, appear to be at odds with simple models of the co-evolution between galaxies and their central BHs. We study the origin of such outliers in a LCDM context using the EAGLE cosmological, hydrodynamical simulation. We find 15 "M_BH(M_star)-outlier" galaxies, defined as having M_BH more than 1.5 dex above the median M_BH(M_star) relation in the simulation, M_{BH,med}. All M_BH(M_star)-outliers are satellite galaxies, typically with M_star ~ 10^10 M_sun and M_BH ~ 10^8 M_sun. They have all become outliers primarily due to tidal stripping of their outer stellar component acting over several Gyr, with a secondary effect of rapid BH growth at high-z causing some to lie approximately 1 dex above the z=0 relation prior to stripping. The same mechanisms also cause the M_BH(M_star)-outlier satellites to be amongst the most compact galaxies in the simulation, making them ideal can...
The four-loop DRED gauge β-function and fermion mass anomalous dimension for general gauge groups
We present four-loop results for the gauge β-function and the fermion mass anomalous dimension for a gauge theory with a general gauge group and a multiplet of fermions transforming according to an arbitrary representation, calculated using the dimensional reduction scheme. In the special case of a supersymmetric theory we confirm previous calculations of both the gauge β-function and the gaugino mass β-function
Shear viscosity of liquid mixtures: Mass dependence
Expressions for zeroth, second, and fourth sum rules of transverse stress autocorrelation function of two component fluid have been derived. These sum rules and Mori's memory function formalism have been used to study shear viscosity of Ar-Kr and isotopic mixtures. It has been found that theoretical result is in good agreement with the computer simulation result for the Ar-Kr mixture. The mass dependence of shear viscosity for different mole fraction shows that deviation from ideal linear model comes even from mass difference in two species of fluid mixture. At higher mass ratio shear viscosity of mixture is not explained by any of the emperical model. (author)
The origin of compact galaxies with anomalously high black hole masses
Barber, Christopher; Schaye, Joop; Bower, Richard G.; Crain, Robert A.; Schaller, Matthieu; Theuns, Tom
2016-07-01
Observations of local galaxies harbouring supermassive black holes (BH) of anomalously high mass, MBH, relative to their stellar mass, M*, appear to be at odds with simple models of the co-evolution between galaxies and their central BHs. We study the origin of such outliers in a Λ cold dark matter context using the EAGLE cosmological, hydrodynamical simulation. We find 15 `MBH(M*)-outlier' galaxies, defined as having MBH more than 1.5 dex above the median MBH(M*) relation in the simulation, MBH, med(M*). All MBH(M*)-outliers are satellite galaxies, typically with M* ˜ 1010 M⊙ and MBH ˜ 108 M⊙. They have all become outliers due to a combination of tidal stripping of their outer stellar component acting over several Gyr and early formation times leading to rapid BH growth at high redshift, with the former mechanism being most important for 67 per cent of these outliers. The same mechanisms also cause the MBH(M*)-outlier satellites to be amongst the most compact galaxies in the simulation, making them ideal candidates for ultracompact dwarf galaxy progenitors. The 10 most extreme central galaxies found at z = 0 (with log10(MBH/MBH, med(M*)) ∈ [1.2, 1.5]) grow rapidly in MBH to lie well above the present-day MBH - M* relation at early times (z ≳ 2), and either continue to evolve parallel to the z = 0 relation or remain unchanged until the present day, making them `relics' of the high-redshift universe. This high-z formation mechanism may help to explain the origin of observed MBH(M*)-outliers with extended dark matter haloes and undisturbed morphologies.
Anomalous length dependence of the conductance of graphene nanoribbons with zigzag edges
Bilić, Ante
2013-01-01
Charge transport through two sets of symmetric graphene nanoribbons with zigzag shaped edges in a two-terminal device has been investigated, using density functional theory combined with the non-equilibrium Green\\'s function method. The conductance has been explored as a function of nanoribbon length, bias voltage, and the strength of terminal coupling. The set of narrower nanoribbons, in the form of thiolated linear acenes, shows an anomalous length dependence of the conductance, which at first exhibits a drop and a minimum, followed by an evident rise. The length trend is shown to arise because of a gradual transformation in the transport mechanism, which changes from being governed by a continuum of out-of-plane π type and in-plane state channels to being fully controlled by a single, increasingly more resonant, occupied π state channel. For the set of nanoribbons with a wider profile, a steady increase is observed across the whole length range, owing to the absence of the former transport mechanism. The predicted trends are confirmed by the inclusion of self-interaction correction in the calculations. For both sets of nanoribbons the replacement of the strongly coupling thiol groups by weakly bonding phenathroline has been found to cause a strong attenuation with the length and a generally low conductance. © 2013 American Institute of Physics.
Kim, Sang-Il; Seo, Min-Su; Park, Seung-Young, E-mail: parksy@kbsi.re.kr [Division of Materials Science, Korea Basic Science Institute, Daejeon 305-806 (Korea, Republic of); Kim, Dong-Jun; Park, Byong-Guk [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of)
2015-05-07
The dependence of the measured DC voltage on the non-magnetic material (NM) in NM/CoFeB and CoFeB/NM bilayers is studied under ferromagnetic resonance conditions in a TE{sub 011} resonant cavity. The directional change of the inverse spin Hall effect (ISHE) voltage V{sub ISHE} for the stacking order of the bilayer can separate the pure V{sub ISHE} and the anomalous Hall effect (AHE) voltage V{sub AHE} utilizing the method of addition and subtraction. The Ta and Ti NMs show a broad deviation of the spin Hall angle θ{sub ISH}, which originates from the AHE in accordance with the high resistivity of NMs. However, the Pt and Pd NMs show that the kinds of NMs with low resistivity are consistent with the previously reported θ{sub ISH} values. Therefore, the characteristics that NM should simultaneously satisfy to obtain a reasonable V{sub ISHE} value in bilayer systems are large θ{sub ISH} and low resistivity.
Layer-dependent quantum cooperation of electron and hole states in the anomalous semimetal WTe2
Das, Pranab Kumar; di Sante, D.; Vobornik, I.; Fujii, J.; Okuda, T.; Bruyer, E.; Gyenis, A.; Feldman, B. E.; Tao, J.; Ciancio, R.; Rossi, G.; Ali, M. N.; Picozzi, S.; Yadzani, A.; Panaccione, G.; Cava, R. J.
2016-02-01
The behaviour of electrons and holes in a crystal lattice is a fundamental quantum phenomenon, accounting for a rich variety of material properties. Boosted by the remarkable electronic and physical properties of two-dimensional materials such as graphene and topological insulators, transition metal dichalcogenides have recently received renewed attention. In this context, the anomalous bulk properties of semimetallic WTe2 have attracted considerable interest. Here we report angle- and spin-resolved photoemission spectroscopy of WTe2 single crystals, through which we disentangle the role of W and Te atoms in the formation of the band structure and identify the interplay of charge, spin and orbital degrees of freedom. Supported by first-principles calculations and high-resolution surface topography, we reveal the existence of a layer-dependent behaviour. The balance of electron and hole states is found only when considering at least three Te-W-Te layers, showing that the behaviour of WTe2 is not strictly two dimensional.
Layer-dependent quantum cooperation of electron and hole states in the anomalous semimetal WTe2.
Das, Pranab Kumar; Di Sante, D; Vobornik, I; Fujii, J; Okuda, T; Bruyer, E; Gyenis, A; Feldman, B E; Tao, J; Ciancio, R; Rossi, G; Ali, M N; Picozzi, S; Yadzani, A; Panaccione, G; Cava, R J
2016-01-01
The behaviour of electrons and holes in a crystal lattice is a fundamental quantum phenomenon, accounting for a rich variety of material properties. Boosted by the remarkable electronic and physical properties of two-dimensional materials such as graphene and topological insulators, transition metal dichalcogenides have recently received renewed attention. In this context, the anomalous bulk properties of semimetallic WTe2 have attracted considerable interest. Here we report angle- and spin-resolved photoemission spectroscopy of WTe2 single crystals, through which we disentangle the role of W and Te atoms in the formation of the band structure and identify the interplay of charge, spin and orbital degrees of freedom. Supported by first-principles calculations and high-resolution surface topography, we reveal the existence of a layer-dependent behaviour. The balance of electron and hole states is found only when considering at least three Te-W-Te layers, showing that the behaviour of WTe2 is not strictly two dimensional. PMID:26924386
Quark mass dependence of H-dibaryon
Yamaguchi, Yasuhiro
2016-01-01
The H-dibaryon is the exotic multiquark state with baryon number 2 and strangeness $-2$. The existence of the deeply bound H-dibaryon is excluded by the observation of the double hypernuclei. However the recent Lattice QCD simulations have found the bound state below the $\\Lambda\\Lambda$ threshold with large quark masses by HALQCD and NPLQCD collaborations. In this talk, the quark mass dependence of the H-dibaryon mass is discussed using the pionless effective field theory (EFT) where a bare H-dibaryon field is coupled with two-baryon states. We determine the parameters in this theory by fitting the recent Lattice QCD results in the SU(3) limit. As a result, we obtain the attractive scattering length at the physical point where the H-dibaryon is unbound.
Thickness Dependence of the Quantum Anomalous Hall Effect in Magnetic Topological Insulator Films.
Feng, Xiao; Feng, Yang; Wang, Jing; Ou, Yunbo; Hao, Zhenqi; Liu, Chang; Zhang, Zuocheng; Zhang, Liguo; Lin, Chaojing; Liao, Jian; Li, Yongqing; Wang, Li-Li; Ji, Shuai-Hua; Chen, Xi; Ma, Xucun; Zhang, Shou-Cheng; Wang, Yayu; He, Ke; Xue, Qi-Kun
2016-08-01
The evolution of the quantum anomalous Hall effect with the thickness of Cr-doped (Bi,Sb)2 Te3 magnetic topological insulator films is studied, revealing how the effect is caused by the interplay of the surface states, band-bending, and ferromagnetic exchange energy. Homogeneity in ferromagnetism is found to be the key to high-temperature quantum anomalous Hall material. PMID:27166762
Charge-dependent correlations from event-by-event anomalous hydrodynamics
Hirono, Yuji; Kharzeev, Dmitri E
2016-01-01
We report on our recent attempt of quantitative modeling of the Chiral Magnetic Effect (CME) in heavy-ion collisions. We perform 3+1 dimensional anomalous hydrodynamic simulations on an event-by-event basis, with constitutive equations that contain the anomaly-induced effects. We also develop a model of the initial condition for the axial charge density that captures the statistical nature of random chirality imbalances created by the color flux tubes. Basing on the event-by-event hydrodynamic simulations for hundreds of thousands of collisions, we calculate the correlation functions that are measured in experiments, and discuss how the anomalous transport affects these observables.
Layer-dependent quantum cooperation of electron and hole states in the anomalous semimetal WTe2
Das, P. K.; Di Sante, D.; Vobornik, I.; Fujii, J.; Okuda, T; Bruyer, E.; Gyenis, A.; Feldman, B; Tao, J.; Ciancio, R.; Rossi, G.; Ali, M.(National Centre for Particle Physics, Universiti Malaya, Kuala Lumpur, Malaysia); Picozzi, S.; Yazdani, A.; G. Panaccione
2016-01-01
The behaviour of electrons and holes in a crystal lattice is a fundamental quantum phenomenon, accounting for a rich variety of material properties. Boosted by the remarkable electronic and physical properties of two-dimensional materials such as graphene and topological insulators, transition metal dichalcogenides have recently received renewed attention. In this context, the anomalous bulk properties of semimetallic WTe2 have attracted considerable interest. Here we report angle- and spin-r...
Čermák, Jiří; Král, Lubomír
Ostrava : Tanger Ltd, 2014. ISBN 978-80-87294-52-9. [Metal 2014. International Conference on Metallurgy and Materials /23./. Brno (CZ), 21.05.2014-23.05.2014] R&D Projects: GA ČR(CZ) GAP108/11/0148; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : Diffusion * Carbon * phase decomposition * Carbon-supersaturation * Cr-Mo steels Subject RIV: BJ - Thermodynamics http://www.metal2014.com/cz/zobrazit-seznam-prispevku/2498-carbon-diffusion-in-carbon-supersaturated-9cr-1mo-steel-anomalous-temperature-dependence-of-carbon-diffusivity/
Gorczyca, I.; Kamińska, A.; Staszczak, G.;
2010-01-01
The pressure-induced changes in the electronic band structures of In-containing nitride alloys, InxGa1-xN and InxAl1-xN are examined experimentally as well as by ab initio calculations. It is found that the band gap pressure coefficients, dEg/dp, exhibit very large bowing with x, and calculations...... with existing data for InxGa1-xN layers. We discuss possible explanations of the anomalously large magnitude of the dEg/dp bowing in these nitride alloys....
Resonant cavity mode dependence of anomalous and inverse spin Hall effect
The direct current electric voltage induced by the Inverse Spin Hall Effect (ISHE) and Anomalous Hall Effect (AHE) was investigated in the TE011 and TE102 cavities. The ISHE and AHE components were distinguishable through the fitting of the voltage spectrum. The unwanted AHE was minimized by placing the DUT (Device Under Test) at the center of both the TE011 and TE102 cavities. The voltage of ISHE in the TE011 cavity was larger than that in the TE102 cavity due to the higher quality factor of the former. Despite optimized centering, AHE voltage from TE011 cavity was also higher. The reason was attributed to the E-field distribution inside the cavity. In the case of the TE011 cavity, the DUT was easily exposed to the E-field in all directions. Therefore, the parasitic AHE voltage in the TE102 cavity was less sensitive than that in the TE011 cavity to decentering problem
The excitation wavelength dependence of the anomalous circular photogalvanic effect (ACPGE) current arising from the reciprocal spin Hall effect (RSHE) in undoped InGaAs/AlGaAs quantum wells is measured under normal incidence of circularly polarized light at room temperature. We found that the spot location with the maximum ACPGE current is wavelength independent. And the normalized ACPGE current decreases at smaller wavelengths, which can be attributed to the sharp decrease of the spin relaxation time (τs) and the hot electron relaxation time (τ1) at smaller wavelengths. The study of the excitation wavelength dependence of ACPGE current is a good supplement to the in-depth investigation of RSHE
Inosov, D. S.; Fink, J.; Kordyuk, A. A.; Borisenko, S. V.; Zabolotnyy, V. B.; Schuster, R.; Knupfer, M.; Büchner, B.; Follath, R.; Dürr, H. A.; Eberhardt, W.; Hinkov, V.; Keimer, B.; Berger, H.
2007-12-01
Using high-resolution angle-resolved photoemission spectroscopy we have studied the momentum and photon energy dependence of the anomalous high-energy dispersion, termed waterfalls, between the Fermi level and 1 eV binding energy in several high-Tc superconductors. We observe strong changes of the dispersion between different Brillouin zones and a strong dependence on the photon energy around 75 eV, which we associate with the resonant photoemission at the Cu3p→3dx2-y2 edge. We conclude that the high-energy “waterfall” dispersion results from a strong suppression of the photoemission intensity at the center of the Brillouin zone due to matrix element effects and is, therefore, not an intrinsic feature of the spectral function. This indicates that the new high-energy scale in the electronic structure of cuprates derived from the waterfall-like dispersion may be incorrect.
Juan Yang; Yu Liu; Daqi Zhang; Xiao Wang; Ruoming Li; Yan Li
2015-01-01
Owing to the unique conjugated structure, the chemical-reaction selectivity of single-walled carbon nanotubes （SWNTs） has attracted great attention. By utilizing the radial deformation of SWNTs caused by the strong interactions with the quartz lattice, we achieve an anomalous diameter-dependent reaction selectivity of quartz lattice-oriented SWNTs in treatment with iodine vapor; this is distinctly different from the widely reported and well accepted higher reaction activity in small-diameter tubes compared to large-diameter tubes. The radial deformation of SWNTs on quartz substrate is verified by detailed Raman spectroscopy and mappings in both G-band and radial breathing mode. Due to the strong interaction between SWNTs and the quartz lattice, large-diameter tubes present a larger degree of radial deformation and more delocalized partial electrons are distributed at certain sidewall sites with high local curvature. It is thus easier for the carbon--carbon bonds at these high-curvature sites on large-diameter tubes to break down during reaction. This anomalous reaction activity offers a novel approach for selective removal of small-band~aD large-diameter tubes.
Relaxation and anomalous T- and H-dependence of the μ coefficient in (K,Ba)BiO3 superconductors
Ac shielding and classical DC relaxation experiments have been used to study the flux creep phenomena in the cubic (K,Ba)BiO3 superconductor (Tc ∝ 30 K). The relaxation rate is found to be constant (S ∝ 1.5%) at low temperature and magnetic field and increases sharply as the vortex-glass transition line is approached. This behavior can be attributed to an anomalous decrease of the μ exponent (U(J) = U0(J0/J)μ) close to Tg(H). In this regime, the temperature dependence of the apparent critical current J is then directly related to μ(T) as J(T) = J0/[kT/U0.ln(1/ωτ)] μ(T). A similar analysis can be made on the J(B) data recently published by Abulafia et al. (1996) on YBaCuO single crystals. (orig.)
Anomalous temperature dependence of PAL and 2D-ACAR in Ni-rich Ni-Ti alloy
Ni-rich NiTi alloys have been investigated by means of PAL spectroscopy, electrical resistivity measurement, 2D-ACAR and first principle calculation. An anomaly of positron lifetime has been observed for Ni52Ti48 alloy which does not exhibit the martensitic transformation: positron lifetime increases by about 25% with lowering temperature. Almost the same change in positron lifetime is observed on the subsequent heating run with little hysteresis. The 2D-ACAR for the same alloy also depends on temperature anomalously: the peak height of the 2D-ACAR increases by 20% and the anisotropy decreases by 60% with lowering temperature. Experimental results are discussed with the idea of Fermi surface nesting of B2-NiTi which has been evaluated from the 2D-ACAR spectra by LCW theory. (orig.)
On the anomalous mass defect of strange stars in the Field Correlator Method
Pereira, F. I. M.
2016-09-01
We investigate general aspects of the mass defects of strange stars in the context of the Field Correlator Method, without magnetic field. The main parameters of the model that enter the corresponding nonperturbative equation of state of the quark gluon plasma are the gluon condensate G2 and the large distance static Q Q bar potential V1. We calculate mass defects of stellar configurations in the central density range 11 quark-novae explosions.
Biswas, Anirban; Khan, Sarif
2016-01-01
The observation of neutrino masses, mixing and the existence of dark matter are amongst the most important signatures of physics beyond the Standard Model (SM). In this paper, we propose to extend the SM by a local $L_\\mu - L_\\tau$ gauge symmetry, two additional complex scalars and three right-handed neutrinos. The $L_\\mu - L_\\tau$ gauge symmetry is broken spontaneously when one of the scalars acquires a vacuum expectation value. The $L_\\mu - L_\\tau$ gauge symmetry is known to be anomaly free and can explain the beyond SM measurement of the anomalous muon $({\\rm g-2})$ through additional contribution arising from the extra $Z_{\\mu\\tau}$ mediated diagram. Small neutrino masses are explained naturally through the Type-I seesaw mechanism, while the mixing angles are predicted to be in their observed ranges due to the broken $L_\\mu-L_\\tau$ symmetry. The second complex scalar is shown to be stable and becomes the dark matter candidate in our model. We show that while the $Z_{\\mu\\tau}$ portal is ineffective for the...
Current mass dependence of the quark condensate and the constituent quark mass
Musakhanov, M.
2001-01-01
We discuss the current mass dependence of the basic quantities of the quark models -- constituent quark mass M and quark condensate i. The framework of the consideration is QCD instanton vacuum model.
Burger, Florian; Hotzel, Grit; Jansen, Karl; Petschlies, Marcus; Renner, Dru B
2013-01-01
We present results for the leading order QCD correction to the anomalous magnetic moment of the muon including the first two generations of quarks as dynamical degrees of freedom. Several light quark masses are examined in order to yield a controlled extrapolation to the physical pion mass. We analyse ensembles for three different lattice spacings and several volumes in order to investigate lattice artefacts and finite-size effects, respectively. We also provide preliminary results for this quantity for two flavours of mass-degenerate quarks at the physical value of the pion mass.
Burger, Florian [Humboldt U. Berlin; Feng, Xu [KEK; Hotzel, Grit [Humboldt U. Berlin; Jansen, Karl [DESY; Petschlies, Marcus [The Cyprus Institute; Renner, Dru B. [JLAB
2013-11-01
We present results for the leading order QCD correction to the anomalous magnetic moment of the muon including the first two generations of quarks as dynamical degrees of freedom. Several light quark masses are examined in order to yield a controlled extrapolation to the physical pion mass. We analyse ensembles for three different lattice spacings and several volumes in order to investigate lattice artefacts and finite-size effects, respectively. We also provide preliminary results for this quantity for two flavours of mass-degenerate quarks at the physical value of the pion mass.
Burger, Florian; Hotzel, Grit [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Feng, Xu [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Petschlies, Marcus [The Cyprus Institute, Nicosia (Cyprus); Renner, Dru B. [Jefferson Lab, Newport News, VA (United States)
2013-12-15
We present results for the leading order QCD correction to the anomalous magnetic moment of the muon including the first two generations of quarks as dynamical degrees of freedom. Several light quark masses are examined in order to yield a controlled extrapolation to the physical pion mass. We analyse ensembles for three different lattice spacings and several volumes in order to investigate lattice artefacts and finite-size effects, respectively. We also provide preliminary results for this quantity for two flavours of mass-degenerate quarks at the physical value of the pion mass.
Impact parameter dependence of isospin effects on the mass dependence of balance energy
Gautam, Sakshi; Sood, Aman D.
2010-01-01
We study the effect of isospin degree of freedom on the balance energy as well as its mass dependence throughout the mass range 48-270 for two sets of isobaric systems with N/Z = 1 and 1.4 using isospin-dependent quantum molecular dynamics (IQMD) model. Our fndings reveal the dominance of Coulomb repulsion in isospin effects on balance energy as well as its mass dependence throughout the range of the colliding geometry.
Anomalous temperature dependence of the Casimir force for thin metal films.
Yampol'skii, V A; Savel'ev, Sergey; Mayselis, Z A; Apostolov, S S; Nori, Franco
2008-08-29
Within the framework of the Drude dispersive model, we predict an unusual nonmonotonic temperature dependence of the Casimir force for thin metal films. For certain conditions, this force decreases with temperature due to the decrease of the metallic conductivity, whereas the force increases at high temperatures due to the increase of the thermal radiation pressure. We consider the attraction of a film to: either (i) a bulk ideal metal with a planar boundary, or (ii) a bulk metal sphere (lens). The experimental observation of the predicted decreasing temperature dependence of the Casimir force can put an end to the long-standing discussion on the role of the electron relaxation in the Casimir effect. PMID:18851637
Arrese-Igor, Silvia; Alegría, Ángel; Moreno Segurado, Ángel J.; Colmenero de León, Juan
2011-01-01
We address the general question of how the molecular weight dependence of chain dynamics in unentangled polymers is modified by blending. By dielectric spectroscopy we measure the normal mode relaxation of polyisoprene in blends with a slower component of poly(ter-butylstyrene). Unentangled polyisoprene in the blend exhibits strong deviations from Rouse scaling, approaching 'entangled-like' behavior at low temperatures in concomitance with the increase of the dynamic asymmetry in the blend. T...
Molecular dynamics simulations of amorphous silica nanowires under tension were analyzed for size and surface stress effects on mechanical properties and for structural modifications via bond angle distributions. Their fracture behavior was also investigated beyond the elastic limit. The Young’s moduli of silica nanowires were predicted to be about 75–100 GPa, depending on the nanowire size. The ultimate strength was calculated to be ∼10 GPa, depending on the diameter, which is in excellent agreement with the experiments. The dependence of the Young’s modulus on nanowire diameter is explained in terms of surface compressive stress effects. The fracture behavior of nanowires was also found to be influenced by surface compressive stresses. Bond angle distribution analysis of various nanowires reveals significant compressive surface states, as evidenced by the appearance of a secondary peak in the Si-O-Si bond angle distribution at ∼97°, which is absent in bulk silica. The strain rate was found to have a negligible effect on the Young’s modulus of the silica nanowires, but it has a critical role in determining their fracture mode. (paper)
Anomalous temperature-dependent spin-valley polarization in monolayer WS2
Hanbicki, A. T.; Kioseoglou, G.; Currie, M.; Hellberg, C. Stephen; McCreary, K. M.; Friedman, A. L.; Jonker, B. T.
2016-01-01
Single layers of transition metal dichalcogenides (TMDs) are direct gap semiconductors with nondegenerate valley indices. An intriguing possibility for these materials is the use of their valley index as an alternate state variable. Several limitations to such a utility include strong intervalley scattering, as well as multiparticle interactions leading to multiple emission channels. We prepare single-layer WS2 films such that the photoluminescence is from either the neutral or charged exciton (trion). After excitation with circularly polarized light, the neutral exciton emission has zero polarization. However, the trion emission has a large polarization (28%) at room temperature. The trion emission also has a unique, non-monotonic temperature dependence that is a consequence of the multiparticle nature of the trion. This temperature dependence enables us to determine that intervalley scattering, electron-hole radiative recombination, and Auger processes are the dominant mechanisms at work in this system. Because this dependence involves trion systems, one can use gate voltages to modulate the polarization (or intensity) emitted from TMD structures.
Dependence of Quark Effective Mass on Gluon Propagators
HE Xiao-Rong; ZHOU Li-Juan; MA Wei-Xing
2005-01-01
Based on Dyson-Schwinger Equations (DSEs) in the "rainbow" approximation, the dependence of quark effective mass on gluon propagator is investigated by use of three different phenomenological gluon propagators with two parameters, the strength parameter x and range parameter △. Our theoretical calculations for the quark effective mass Mf(p2), defined by the self-energy functions Af(p2) and Bf(p2) of the DSEs, show that the dynamically running quark effective mass is strongly dependent on gluon propagator. Therefore, because gluon propagator is completely unknown,the quark effective mass cannot be exactly determined theoretically.
Four-loop β function and mass anomalous dimension in dimensional reduction
Within the framework of QCD we compute renormalization constants for the strong coupling and the quark masses to four-loop order. We apply the D-bar R-bar scheme and put special emphasis on the additional couplings which have to be taken into account. This concerns the ε-scalar-quark Yukawa coupling as well as the vertex containing four ε-scalars. For a supersymmetric Yang Mills theory, we find, in contrast to a previous claim, that the evanescent Yukawa coupling equals the strong coupling constant through three loops as required by supersymmetry
Glacier mass balance in high-arctic areas with anomalous gravity
Sharov, A.; Rieser, D.; Nikolskiy, D.
2012-04-01
All known glaciological models describing the evolution of Arctic land- and sea-ice masses in changing climate treat the Earth's gravity as horizontally constant, but it isn't. In the High Arctic, the strength of the gravitational field varies considerably across even short distances under the influence of a density gradient, and the magnitude of free air gravity anomalies attains 100 mGal and more. On long-term base, instantaneous deviations of gravity can have a noticeable effect on the regime and mass budget of glaciological objects. At best, the gravity-induced component of ice mass variations can be determined on topographically smooth, open and steady surfaces, like those of arctic planes, regular ice caps and landfast sea ice. The present research is devoted to studying gravity-driven impacts on glacier mass balance in the outer periphery of four Eurasian shelf seas with a very cold, dry climate and rather episodic character of winter precipitation. As main study objects we had chosen a dozen Russia's northernmost insular ice caps, tens to hundreds of square kilometres in extent, situated in a close vicinity of strong gravity anomalies and surrounded with extensive fields of fast and/or drift ice for most of the year. The supposition about gravitational forcing on glacioclimatic settings in the study region is based on the results of quantitative comparison and joint interpretation of existing glacier change maps and available data on the Arctic gravity field and solid precipitation. The overall mapping of medium-term (from decadal to half-centennial) changes in glacier volumes and quantification of mass balance characteristics in the study region was performed by comparing reference elevation models of study glaciers derived from Russian topographic maps 1:200,000 (CI = 20 or 40 m) representing the glacier state as in the 1950s-1980s with modern elevation data obtained from satellite radar interferometry and lidar altimetry. Free-air gravity anomalies were
Iha, Hisashi; Suzuki, Hiroshi
2016-01-01
We study four-dimensional conformal field theories with an $SU(N)$ global symmetry by employing the numerical conformal bootstrap. We consider the crossing relation associated with a four-point function of a spin~$0$ operator~$\\phi_i^{\\Bar{k}}$ which belongs to the adjoint representation of~$SU(N)$. For~$N=12$ for example, we found that the theory contains a spin~$0$ $SU(12)$-breaking relevant operator if the scaling dimension of~$\\phi_i^{\\Bar{k}}$, $\\Delta_{\\phi_i^{\\Bar{k}}}$, is smaller than~$1.63$. Considering the lattice simulation of the many-flavor QCD with $12$~flavors on the basis of the staggered fermion, the above $SU(12)$-breaking relevant operator, if it exists, would be induced by the flavor breaking effect of the staggered fermion and would prevent an approach to an infrared fixed point. Actual lattice simulations do not show such signs. Thus, assuming the absence of the above $SU(12)$-breaking relevant operator, we have an upper bound on the mass anomalous dimension at the fixed point~$\\gamma_m...
Iha, Hisashi; Makino, Hiroki; Suzuki, Hiroshi
2016-05-01
We study four-dimensional conformal field theories with an SU(N) global symmetry by employing the numerical conformal bootstrap. We consider the crossing relation associated with a four-point function of a spin 0 operator φ _i^{bar {k}} which belongs to the adjoint representation of SU(N). For N=12 for example, we found that the theory contains a spin 0 SU(12)-breaking relevant operator when the scaling dimension of φ _i^{bar {k}}, Δ _{φ _i^{bar {k}}}, is smaller than 1.71. Considering the lattice simulation of many-flavor quantum chromodynamics with 12 flavors on the basis of the staggered fermion, the above SU(12)-breaking relevant operator, if it exists, would be induced by the flavor-breaking effect of the staggered fermion and prevent an approach to an infrared fixed point. Actual lattice simulations do not show such signs. Thus, assuming the absence of the above SU(12)-breaking relevant operator, we have an upper bound on the mass anomalous dimension at the fixed point γ _m^*≤ 1.29 from the relation γ _m^*=3-Δ _{φ _i^{bar {k}}}. Our upper bound is not so strong practically but it is strict within the numerical accuracy. We also find a kink-like behavior in the boundary curve for the scaling dimension of another SU(12)-breaking operator.
Seki, Kazuhiko; Bagchi, Kaushik; Bagchi, Biman
2016-05-21
Diffusion in one dimensional rugged energy landscape (REL) is predicted to be pathologically different (from any higher dimension) with a much larger chance of encountering broken ergodicity [D. L. Stein and C. M. Newman, AIP Conf. Proc. 1479, 620 (2012)]. However, no quantitative study of this difference has been reported, despite the prevalence of multidimensional physical models in the literature (like a high dimensional funnel guiding protein folding/unfolding). Paradoxically, some theoretical studies of these phenomena still employ a one dimensional diffusion description for analytical tractability. We explore the dimensionality dependent diffusion on REL by carrying out an effective medium approximation based analytical calculations and compare them with the available computer simulation results. We find that at an intermediate level of ruggedness (assumed to have a Gaussian distribution), where diffusion is well-defined, the value of the effective diffusion coefficient depends on dimensionality and changes (increases) by several factors (∼5-10) in going from 1d to 2d. In contrast, the changes in subsequent transitions (like 2d to 3d and 3d to 4d and so on) are far more modest, of the order of 10-20% only. When ruggedness is given by random traps with an exponential distribution of barrier heights, the mean square displacement (MSD) is sub-diffusive (a well-known result), but the growth of MSD is described by different exponents in one and higher dimensions. The reason for such strong ruggedness induced retardation in the case of one dimensional REL is discussed. We also discuss the special limiting case of infinite dimension (d = ∞) where the effective medium approximation becomes exact and where theoretical results become simple. We discuss, for the first time, the role of spatial correlation in the landscape on diffusion of a random walker. PMID:27208935
Kimball, Derek F.J.; Lacey, Ian; Valdez, Julian; Swiatlowski, Jerlyn; Rios, Cesar; Peregrina-Ramirez, Rodrigo; Montcrieffe, Caitlin; Kremer, Jackie; Dudley, Jordan; Sanchez, C. [Department of Physics, California State University - East Bay, Hayward, California, 94542-3084 (United States)
2013-07-15
The experimental concept of a search for a long-range coupling between rubidium (Rb) nuclear spins and the mass of the Earth is described. The experiment is based on simultaneous measurement of the spin precession frequencies for overlapping ensembles of {sup 85}Rb and {sup 87}Rb atoms contained within an evacuated, antirelaxation-coated vapor cell. Rubidium atoms are spin-polarized in the presence of an applied magnetic field by synchronous optical pumping with circularly polarized laser light. Spin precession is probed by measuring optical rotation of far-off-resonant, linearly polarized laser light. Simultaneous measurement of {sup 85}Rb and {sup 87}Rb spin precession frequencies enables suppression of magnetic-field-related systematic effects. The nuclear structure of the Rb isotopes makes the experiment particularly sensitive to anomalous spin-dependent interactions of the proton. Experimental sensitivity and a variety of systematic effects are discussed, and initial data are presented. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Mass-dependent Lorentz Violation and Neutrino Velocity
Li, Miao
2011-01-01
Motivated by a recent and several earlier measurement results of the neutrino velocity, we attempt to resolve the apparent discrepancies between them from the viewpoint of mass-energy relation in special relativity. It is argued that a complicated tachyonic neutrino model or a mass-dependent Lorentz violation theory can do this job.
High temperature, self-propagating reactions are observed in vapor-deposited Al/Zr multilayered foils of overall atomic ratios 3 Al:1 Zr and 2 Al:1 Zr and nanoscale layer thicknesses; however, the reaction velocities do not exhibit the inverse dependence on bilayer thickness that is expected based on changes in the average diffusion distance. Instead, for bilayer thicknesses of 20-30 nm, the velocity is essentially constant at ∼7.7 m/s. We explore several possible explanations for this anomalous behavior, including microstructural factors, changes in the phase evolution, and phase transformations in the reactant layers, but find no conclusive explanations. We determine that the phase evolution during self-propagating reactions in foils with a 3 Al:1 Zr stoichiometry is a rapid transformation from Al/Zr multilayers to the equilibrium intermetallic Al3Zr compound with no intermediate crystalline phases. This phase evolution is the same for foils of 90 nm bilayer thicknesses and foils of bilayer thicknesses in the range of 27 nm to 35 nm. Further, for foils with a bilayer thickness of 90 nm and a 3 Al:1 Zr overall chemistry, the propagation front is planar and steady, in contrast to unsteady reaction fronts in foils with 1 Al:1 Zr overall chemistry and similar bilayer thicknesses
Anand, Mohit; Sinha, Anil K
2012-12-01
Kinetic studies and product profiling was done to understand the anomalous cracking of jathropha oil triglycerides in the presence of sulfided Co-Mo/Al(2)O(3) catalyst. At temperatures between 320 and 340 °C, only deoxygenation and oligomerization reactions took place whereas at temperatures above 340 °C, internal conversions between the products and direct conversion to lighter and middle distillates were favored High pressures (80 bar) and H(2)/feed ratios (>1500) were necessary to minimize oligomerization of the products and to increase the lifespan of the catalyst. Lumped kinetic models were validated with experimental results. Activation energies for the formation of lighter (83 kJ/mol) and middle fractions (126 kJ/mol) were higher than those for the heavy (47 kJ/mol) and deoxygenated (47 kJ/mol) products. Jatropha oil triglycerides hydroconversion pathways were dependent on temperature and the triglycerides could be hydrocracked to lower range hydrocarbons (C5-C14) by increasing the reaction temperatures. PMID:23073102
Harmonic oscillator with time - dependent mass and frequency
A general treatment of the quantal harmonic oscillator with time-dependent mass and frequency is presented. The treatment is based on the use of some time-dependent transformations in the method of invariants of Lewis and Riesenfeld. Exact coherent states for such a system are also constructed. (A.C.A.S.)
Yang, Y. J.; Bao, J.; Gao, C., E-mail: zlluo@ustc.edu.cn, E-mail: cgao@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230026 (China); CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Yang, M. M.; Luo, Z. L., E-mail: zlluo@ustc.edu.cn, E-mail: cgao@ustc.edu.cn; Hu, C. S.; Chen, X. C.; Pan, G. Q. [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230026 (China); Huang, H. L. [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, S.; Wang, J. W.; Li, P. S.; Liu, Y.; Zhao, Y. G. [Department of Physics and State Key Laboratory of New Ceramics, Fine Processing, Tsinghua University, Beijing 100084 (China); Jiang, T.; Liu, Y. K.; Li, X. G. [Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science, Technology of China, Hefei, Anhui 230026 (China)
2014-05-07
A series of Zn{sub x}Fe{sub 3−x}O{sub 4} (ZFO, x = 0.4) thin films were epitaxially deposited on single-crystal (001)-SrTiO{sub 3} (STO) substrates by radio frequency magnetron sputtering. The anomalous thickness-dependent strain states of ZFO films were found, i.e., a tensile in-plane strain exists in the thinner ZFO film and which monotonously turns into compressive in the thicker films. Considering the lattice constant of bulk ZFO is bigger than that of STO, this strain state cannot be explained in the conventional framework of lattice-mismatch-induced strain in the hetero-epitaxial system. This unusual phenomenon is proposed to be closely related to the Volmer-Weber film growth mode in the thinner films and incorporation of the interstitial atoms into the island's boundaries during subsequent epitaxial growth of the thicker films. The ZFO/STO epitaxial film is found in the nature of magnetic semiconductor by transport measurements. The in-plane magnetization of the ZFO/STO films is found to increase as the in-plane compressive strain develops, which is further proved in the (001)-ZFO/PMN-PT film where the film strain state can be in situ controlled with applied electric field. This compressive-strain-enhanced magnetization can be attributed to the strain-mediated electric-field-induced in-plane magnetic anisotropy field enhancement. The above results indicate that strain engineering on magnetic oxide semiconductor ZFO films is promising for novel oxide-electronic devices.
Yang, Y. J.; Yang, M. M.; Luo, Z. L.; Hu, C. S.; Bao, J.; Huang, H. L.; Zhang, S.; Wang, J. W.; Li, P. S.; Liu, Y.; Zhao, Y. G.; Chen, X. C.; Pan, G. Q.; Jiang, T.; Liu, Y. K.; Li, X. G.; Gao, C.
2014-05-01
A series of ZnxFe3-xO4 (ZFO, x = 0.4) thin films were epitaxially deposited on single-crystal (001)-SrTiO3 (STO) substrates by radio frequency magnetron sputtering. The anomalous thickness-dependent strain states of ZFO films were found, i.e., a tensile in-plane strain exists in the thinner ZFO film and which monotonously turns into compressive in the thicker films. Considering the lattice constant of bulk ZFO is bigger than that of STO, this strain state cannot be explained in the conventional framework of lattice-mismatch-induced strain in the hetero-epitaxial system. This unusual phenomenon is proposed to be closely related to the Volmer-Weber film growth mode in the thinner films and incorporation of the interstitial atoms into the island's boundaries during subsequent epitaxial growth of the thicker films. The ZFO/STO epitaxial film is found in the nature of magnetic semiconductor by transport measurements. The in-plane magnetization of the ZFO/STO films is found to increase as the in-plane compressive strain develops, which is further proved in the (001)-ZFO/PMN-PT film where the film strain state can be in situ controlled with applied electric field. This compressive-strain-enhanced magnetization can be attributed to the strain-mediated electric-field-induced in-plane magnetic anisotropy field enhancement. The above results indicate that strain engineering on magnetic oxide semiconductor ZFO films is promising for novel oxide-electronic devices.
The high-pressure compression behaviour of 3 different cation forms of gallosilicate zeolite with CGS topology has been investigated using in situ synchrotron X-ray powder diffraction and a diamond-anvil cell technique. Under hydrostatic conditions mediated by a nominally penetrating pressure-transmitting medium, unit-cell lengths and volume compression is modulated by different degrees of pressure-induced hydration and accompanying channel distortion. In a Na-exchanged CGS (Na10Ga10Si22O64.16H2O), the unit-cell volume expands by ca. 0.6% upon applying hydrostatic pressure to 0.2 GPa, whereas, in an as-synthesized K-form (K10Ga10Si22O64.5H2O), this initial volume expansion is suppressed to ca. 0.1% at 0.16 GPa. In the early stage of hydrostatic compression below ∼1 GPa, relative decrease in the ellipticity of the non-planar 10-rings is observed, which is then reverted to a gradual increase in the ellipticity at higher pressures above ∼1 GPa, implying a change in the compression mechanism. In a Sr-exchanged sample (Sr5Ga10Si22O64.19H2O), on the other hand, no initial volume expansion is observed. Instead, a change in the slope of volume contraction is observed near 1.5 GPa, which leads to a 2-fold increase in the compressibility. This is interpreted as pressure-induced rearrangement of water molecules to facilitate further volume contraction at higher pressures. - Graphical abstract: Three different cation forms of gallosilicate CGS zeolites have been investigated using synchrotron X-ray powder diffraction and a diamond-anvil cell. Under hydrostatic conditions, unit-cell lengths and volume show anomalous compression behaviours depending on the non-framework cation type and initial hydration level, which implies different modes of pressure-induced hydration and channel distortion
Pan, S. S., E-mail: sspan@issp.ac.cn, E-mail: ghli@issp.ac.cn; Li, F. D.; Liu, Q. W.; Xu, S. C.; Luo, Y. Y. [Key Laboratory of Materials Physics, Anhui Key Laboratory of Nanomaterials and Nanostructures, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Li, G. H., E-mail: sspan@issp.ac.cn, E-mail: ghli@issp.ac.cn [Key Laboratory of Materials Physics, Anhui Key Laboratory of Nanomaterials and Nanostructures, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026 (China)
2015-05-07
SnO{sub 2} quantum dots (QDs) are potential materials for deep ultraviolet (DUV) light emitting devices. In this study, we report the temperature and excitation power-dependent exciton luminescence from SnO{sub 2} QDs. The exciton emission exhibits anomalous blue shift, accompanied with band width reduction with increasing temperature and excitation power above 300 K. The anomalous temperature dependences of the peak energy and band width are well interpreted by the strongly localized carrier thermal hopping process and Gaussian shape of band tails states, respectively. The localized wells and band tails at conduction minimum are considered to be induced by the surface oxygen defects and local potential fluctuation in SnO{sub 2} QDs.
Pion-mass dependence of three-nucleon observables
Hammer, H. -W.; D. R. Phillips; Platter, L.
2007-01-01
We use an effective field theory (EFT) which contains only short-range interactions to study the dependence of a variety of three-nucleon observables on the pion mass. The pion-mass dependence of input quantities in our ``pionless'' EFT is obtained from a recent chiral EFT calculation. To the order we work at, these quantities are the 1S0 scattering length and effective range, the deuteron binding energy, the 3S1 effective range, and the binding energy of one three-nucleon bound state. The ch...
Isotopic mass-dependence of noble gas diffusion coefficients inwater
Bourg, I.C.; Sposito, G.
2007-06-25
Noble gas isotopes are used extensively as tracers inhydrologic and paleoclimatic studies. These applications requireknowledge of the isotopic mass (m) dependence of noble gas diffusioncoefficients in water (D), which has not been measured but is estimatedusing experimental D-values for the major isotopes along with an untestedrelationship from kinetic theory, D prop m-0.5. We applied moleculardynamics methods to determine the mass dependence of D for four noblegases at 298 K, finding that D prop m-beta with beta<0.2, whichrefutes the kinetic theory model underlying all currentapplications.
On the quark-mass dependence of the baryon ground-state masses
Semke, A
2011-01-01
We perform a chiral extrapolation of the baryon octet and decuplet masses in a relativistic formulation of chiral perturbation theory. A partial summation is assumed as implied by the use of physical baryon and meson masses in the one-loop diagrams. Upon a chiral expansion our results are consistent with strict chiral perturbation theory at the next-to-next-to-next-to-leading order. All counter terms are correlated by a large-$N_c$ operator analysis. Our results are confronted with recent results of unquenched three flavor lattice simulations. We adjust the parameter set to the pion-mass dependence of the nucleon and omega masses as computed by the BMW group and predict the pion-mass dependence of the remaining baryon octet and decuplet states. The current lattice simulations can be described accurately and smoothly up to pion masses of about 600 MeV. In particular we recover the recent results of HSC without any further adjustments.
Analysis of the mass formula dependence of spallation product distribution
A new version of a spallation reaction simulation code NUCLEUS has been developed by incorporating the newly revised Uno and Yamada's mass formula. The mass formula dependence of the spallation product distribution has been investigated by comparing the new results with those calculated by the original version which uses the combination of the Cameron's mass formula and the mass table compiled by Wapstra et al. Detailed differences between these two mass formulas are shown in the comparisons of mass excess values. The distributions of spallation products of a uranium target nucleus bombarded by high energy (0.38 - 2.9 GeV) protons have been calculated with the new and original versions of NUCLEUS. The calculated results show that there is no significant discrepancy in the non-fission component of cumulative product yields such as the mass distribution and the number of emitted neutrons but in the fission component Uno and Yamada's mass formula reproduces the measured data obtained from thin foil experiments significantly better, especially in the neutron excess side, than the Cameron's one. (author)
Haham, N.; Konczykowski, M.; Kuiper, B.; Koster, G.; Klein, L.
2013-01-01
We measure the anomalous Hall effect (AHE) in several patterns of the itinerant ferromagnet SrRuO 3 before and after the patterns are irradiated with electrons. The irradiation increases the resistivity of the patterns due to the introduction of point defects and we find that the AHE coefficient R
Inclination Dependence of Estimated Galaxy Masses and Star Formation Rates
Hernandez, Betsy; Maller, Ariyeh; McKernan, Barry; Ford, Saavik
2016-01-01
We examine the inclination dependence of inferred star formation rates and galaxy mass estimates in the Sloan Digital Sky Survey by combining the disk/bulge de-convolved catalog of Simard et al 2011 with stellar mass estimates catalog of Mendel et al 2014 and star formation rates measured from spectra by Brinchmann et al 2004. We know that optical star formation indicators are reddened by dust, but calculated star formation rates and stellar mass estimates should account for this. However, we find that face-on galaxies have a higher calculated average star formation rates than edge-on galaxies. We also find edge-on galaxies have ,on average, slightly smaller but similar estimated masses to face-on galaxies, suggesting that there are issues with the applied dust corrections for both models.
The dependence of quasar variability on black hole mass
Wold, M; Shang, Z
2006-01-01
In order to investigate the dependence of quasar variability on fundamental physical parameters like black hole mass, we have matched quasars from the QUEST1 Variability Survey with broad-lined objects from the Sloan Digital Sky Survey. The matched sample contains approximately 100 quasars, and the Sloan spectra are used to estimate black hole masses and bolometric luminosities. Variability amplitudes are measured from the QUEST1 light curves. We find that black hole mass correlates with several measures of the variability amplitude at the 99% significance level or better. The correlation does not appear to be caused by obvious selection effects inherent to flux-limited quasar samples, host galaxy contamination or other well-known correlations between quasar variability and luminosity/redshift. We evaluate variability as a function of rest-frame time lag using structure functions, and find further support for the variability--black hole mass correlation. The correlation is strongest for time lags of the order...
The dependence of convective core overshooting on stellar mass
Claret, Antonio
2016-01-01
Convective core overshooting extends the main-sequence lifetime of a star. Evolutionary tracks computed with overshooting are quite different from those that use the classical Schwarzschild criterion, which leads to rather different predictions for the stellar properties. Attempts over the last two decades to calibrate the degree of overshooting with stellar mass using detached double-lined eclipsing binaries have been largely inconclusive, mainly due to a lack of suitable observational data. Here we revisit the question of a possible mass dependence of overshooting with a more complete sample of binaries, and examine any additional relation there might be with evolutionary state or metal abundance Z. We use a carefully selected sample of 33 double-lined eclipsing binaries strategically positioned in the H-R diagram, with accurate absolute dimensions and component masses ranging from 1.2 to 4.4 solar masses. We compare their measured properties with stellar evolution calculations to infer semi-empirical value...
Zhu, Laipan; Liu, Yu; Gao, Hansong; Qin, Xudong; Li, Yuan; Wu, Qing; Chen, Yonghai
2014-01-01
We observed an anomalous linear photogalvanic effect (ALPGE) in undoped InGaAs/AlGaAs multiple quantum well and studied its wavelength dependence in details. This effect is believed to originate from the optical momentum alignment effect and the inhomogeneity of light intensity. We find that the spot location with the maximum ALPGE current is wavelength independent. And the normalized ALPGE current decreasing at smaller wavelengths is attributed to the sharp decrease of the momentum and energy relaxation time. The electrical measurement of the spectra dependence of ALPGE is highly sensitive proving to be an effective method for detecting the momentum anisotropy of photoinduced carriers and band coupling. PMID:25258612
Quark mass dependence of the X(3872) binding energy
Baru, V; Filin, A A; Hanhart, C; Meißner, U -G; Nefediev, A V
2013-01-01
We explore the quark-mass dependence of the pole position of the X(3872) state within the molecular picture. The calculations are performed within the framework of a nonrelativistic Faddeev-type three-body equation for the $D\\bar{D}\\pi$ system in the $J^{PC}=1^{++}$ channel. The $\\pi D$ interaction is parametrised via a $D^*$ pole, and a three-body force is included to render the equations well defined. Its strength is adjusted such that the X(3872) appears as a $D\\bar{D}^*$ bound state 0.5 MeV below the neutral threshold. We find that the trajectory of the X(3872) depends strongly on the assumed quark-mass dependence of the short-range interactions which can be determined in future lattice QCD calculations. At the same time we are able to provide nontrivial information on the chiral extrapolation in the $X$ channel.
Anomalous Dimensions of Conformal Baryons
Pica, Claudio
2016-01-01
We determine the anomalous dimensions of baryon operators for the three color theory as function of the number of massless flavours within the conformal window to the maximum known order in perturbation theory. We show that the anomalous dimension of the baryon is controllably small for a wide range of number of flavours. We also find that this is always smaller than the anomalous dimension of the fermion mass operator. These findings challenge the partial compositeness paradigm.
A Stellar-mass-dependent Drop in Planet Occurrence Rates
Mulders, Gijs D.; Pascucci, Ilaria; Apai, Dániel
2015-01-01
The Kepler spacecraft has discovered a large number of planets with up to one-year periods and down to terrestrial sizes. While the majority of the target stars are main-sequence dwarfs of spectral type F, G, and K, Kepler covers stars with effective temperatures as low as 2500 K, which corresponds to M stars. These cooler stars allow characterization of small planets near the habitable zone, yet it is not clear if this population is representative of that around FGK stars. In this paper, we calculate the occurrence of planets around stars of different spectral types as a function of planet radius and distance from the star and show that they are significantly different from each other. We further identify two trends. First, the occurrence of Earth- to Neptune-sized planets (1-4 R ⊕) is successively higher toward later spectral types at all orbital periods probed by Kepler; planets around M stars occur twice as frequently as around G stars, and thrice as frequently as around F stars. Second, a drop in planet occurrence is evident at all spectral types inward of a ~10 day orbital period, with a plateau further out. By assigning to each spectral type a median stellar mass, we show that the distance from the star where this drop occurs is stellar mass dependent, and scales with semi-major axis as the cube root of stellar mass. By comparing different mechanisms of planet formation, trapping, and destruction, we find that this scaling best matches the location of the pre-main-sequence co-rotation radius, indicating efficient trapping of migrating planets or planetary building blocks close to the star. These results demonstrate the stellar-mass dependence of the planet population, both in terms of occurrence rate and of orbital distribution. The prominent stellar-mass dependence of the inner boundary of the planet population shows that the formation or migration of planets is sensitive to the stellar parameters.
A STELLAR-MASS-DEPENDENT DROP IN PLANET OCCURRENCE RATES
The Kepler spacecraft has discovered a large number of planets with up to one-year periods and down to terrestrial sizes. While the majority of the target stars are main-sequence dwarfs of spectral type F, G, and K, Kepler covers stars with effective temperatures as low as 2500 K, which corresponds to M stars. These cooler stars allow characterization of small planets near the habitable zone, yet it is not clear if this population is representative of that around FGK stars. In this paper, we calculate the occurrence of planets around stars of different spectral types as a function of planet radius and distance from the star and show that they are significantly different from each other. We further identify two trends. First, the occurrence of Earth- to Neptune-sized planets (1-4 R ⊕) is successively higher toward later spectral types at all orbital periods probed by Kepler; planets around M stars occur twice as frequently as around G stars, and thrice as frequently as around F stars. Second, a drop in planet occurrence is evident at all spectral types inward of a ∼10 day orbital period, with a plateau further out. By assigning to each spectral type a median stellar mass, we show that the distance from the star where this drop occurs is stellar mass dependent, and scales with semi-major axis as the cube root of stellar mass. By comparing different mechanisms of planet formation, trapping, and destruction, we find that this scaling best matches the location of the pre-main-sequence co-rotation radius, indicating efficient trapping of migrating planets or planetary building blocks close to the star. These results demonstrate the stellar-mass dependence of the planet population, both in terms of occurrence rate and of orbital distribution. The prominent stellar-mass dependence of the inner boundary of the planet population shows that the formation or migration of planets is sensitive to the stellar parameters
A STELLAR-MASS-DEPENDENT DROP IN PLANET OCCURRENCE RATES
Mulders, Gijs D.; Pascucci, Ilaria [Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States); Apai, Dániel [Department of Astronomy, The University of Arizona, Tucson, AZ 85721, USA. (United States)
2015-01-10
The Kepler spacecraft has discovered a large number of planets with up to one-year periods and down to terrestrial sizes. While the majority of the target stars are main-sequence dwarfs of spectral type F, G, and K, Kepler covers stars with effective temperatures as low as 2500 K, which corresponds to M stars. These cooler stars allow characterization of small planets near the habitable zone, yet it is not clear if this population is representative of that around FGK stars. In this paper, we calculate the occurrence of planets around stars of different spectral types as a function of planet radius and distance from the star and show that they are significantly different from each other. We further identify two trends. First, the occurrence of Earth- to Neptune-sized planets (1-4 R {sub ⊕}) is successively higher toward later spectral types at all orbital periods probed by Kepler; planets around M stars occur twice as frequently as around G stars, and thrice as frequently as around F stars. Second, a drop in planet occurrence is evident at all spectral types inward of a ∼10 day orbital period, with a plateau further out. By assigning to each spectral type a median stellar mass, we show that the distance from the star where this drop occurs is stellar mass dependent, and scales with semi-major axis as the cube root of stellar mass. By comparing different mechanisms of planet formation, trapping, and destruction, we find that this scaling best matches the location of the pre-main-sequence co-rotation radius, indicating efficient trapping of migrating planets or planetary building blocks close to the star. These results demonstrate the stellar-mass dependence of the planet population, both in terms of occurrence rate and of orbital distribution. The prominent stellar-mass dependence of the inner boundary of the planet population shows that the formation or migration of planets is sensitive to the stellar parameters.
Mass-dependence of self-diffusion coefficients in disparate-mass binary fluid mixtures
I. Binas; I.Mryglod
2009-01-01
Self-diffusion coefficients of a binary fluid mixture with components differing only in their particle masses are studied, in particular the case when mass ratio μ of light and heavy particles tends to zero. These coefficients were calculated within the memory function formalism, using the systematic subsequence of approximations for the relaxation times of velocity autocorrelation function. We obtained a general relation for the self-diffusion coefficients which show polynomial dependence on...
Exactly solvable potentials with finite positive position-dependent mass
Complete text of publication follows. Quantum mechanical potential problems with position-dependent mass occur in various branches of physics. There have been considerable efforts recently to obtain the exact analytical solution of the Schroedinger equation with various effective masses, but the results are less numerous and less systematic than in the case of constant-mass potential problems. The quantum mechanically acceptable one-dimensional position-dependent mass problems can be transformed to the form (- d/dx 1/M(x) d/dx + Veff (x)) ψ(x) = Eψ(x). (1) The procedure of solving this equation is usually done by adapting the methods applied in the constant mass case, i.e. Eq. (1) is transformed to the differential equation of some F special function of mathematical physics by substituting ψ(x) = f(x)F(g(x)). The g(x) function maps the domain of definition of ψ to that of F in a monotonous way. The mass function M(x) also has to be included in this procedure, and in the previous works it has been defined in terms of the derivative of g(x). Since g(x) and g'(x) are usually not bound and can be zero, the resulting mass function also has these features typically. The physical interpretation of the zeros and the singularities of M(x) usually need some kind of justification, but it may not be compatible with the actual physical nature of the problem. Recently we generalized the procedure of solving the position-dependent mass Schroedinger equation in a way that guarantees that M(x) remains finite and positive everywhere. We developed the formalism for the generalized Laguerre polynomials F(g) = Lnα (g) and considered the mass function M(g(x)) M0(γ + g(x))(δ + g(x))-1. The g(x) function was defined by g'(x) g(x)[B(δ + g(x)]-1/2, which contains as special cases the g(x) functions generating the harmonic oscillator (δ = 0) and the Morse potential (δ → ∞, Bδ = const.). Integrating g'(x) results in an implicit x(g) function x + K = (Bδ)1/2 ln ((δ + g)1/2 -
Anomalous Magnetohydrodynamics
Giovannini, Massimo
2013-01-01
Anomalous symmetries induce currents which can be parallel rather than orthogonal to the hypermagnetic field. Building on the analogy with charged liquids at high magnetic Reynolds numbers, the persistence of anomalous currents is scrutinized for parametrically large conductivities when the plasma approximation is accurate. Different examples in globally neutral systems suggest that the magnetic configurations minimizing the energy density with the constraint that the helicity be conserved co...
Anomalous bootstrap current due to drift waves
An anomalous parallel current driven by radial flux in tokamak is discussed. Drift waves, which cause an anomalous cross field diffusion, can generate a parallel current in a sheared magnetic field, if the fluctuation level has radial dependence. (author)
Noncommutativity into Dirac Equation with mass dependent on the position
Full text: In recent years, there is growing interest in the study of theories in non-commutative spaces. Non-commutative fields theories are related with compactifications of M theory, string theory and the quantum Hall effect. Moreover, the role of the non-commutativity of theories of a particle finds large applications when analyzed in scenarios of quantum mechanics and relativistic quantum mechanics. In these contexts investigations on the Schrodinger and Dirac equations with mass depending on the position (MDP) has attracted much attention in the literature. Systems endowed with MDP models are useful for the study of many physical problems. In particular, they are used to study the energy density in problems of many bodies, determining the electronic properties of semiconductor heterostructures and also to describe the properties of heterojunctions and quantum dots. In particular, the investigation of relativistic effects it is important for systems containing heavy atoms or doping by heavy ions. For these types of materials, the study of the properties of the Dirac equation, in the case where the mass becomes variable is of great interest. In this paper, we seek for the non-relativistic limit of the Dirac Hamiltonian in the context of a theory of effective mass, through a Foldy-Wouthuysen transformation. We analyse the Dirac equation with mass dependent on the position, in a smooth step shape mass distribution, in non-commutative space (NC). This potential type kink was recently discussed by several authors in the commutative context and now we present our results in the non-commutative context. (author)
Galaxy metallicities depend primarily on stellar mass and molecular gas mass
Bothwell, M S; Cicone, C; Peng, Y; Wagg, J
2016-01-01
In this work we present an analysis of the behaviour of galaxies in a four-dimensional parameter space defined by stellar mass, metallicity, star formation rate, and molecular gas mass. We analyse a combined sample of 227 galaxies, which draws from a number of surveys across the redshift range 0 90% of the sample at z~0), and covers > 3 decades in stellar mass.Using Principle Component Analysis, we demonstrate that galaxies in our sample lie on a 2-dimensional plane within this 4D parameter space, indicative of galaxies that exist in an equilibrium between gas inflow and outflow. Furthermore, we find that the metallicity of galaxies depends only on stellar mass and molecular gas mass. In other words, gas-phase metallicity has a negligible dependence on star formation rate, once the correlated effect of molecular gas content is accounted for. The well-known `fundamental metallicity relation', which describes a close and tight relationship between metallicity and SFR (at fixed stellar mass) is therefore entire...
Quark mass dependence of the X(3872) binding energy
Baru, V., E-mail: vadimb@tp2.rub.de [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya 25, 117218 Moscow (Russian Federation); Epelbaum, E. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Filin, A.A. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya 25, 117218 Moscow (Russian Federation); Hanhart, C. [Forschungszentrum Jülich, Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, D-52425 Jülich (Germany); Meißner, U.-G. [Forschungszentrum Jülich, Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, D-52425 Jülich (Germany); Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn (Germany); Nefediev, A.V. [Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya 25, 117218 Moscow (Russian Federation); National Research Nuclear University MEPhI, 115409, Moscow (Russian Federation); Moscow Institute of Physics and Technology, 141700, Dolgoprudny, Moscow Region (Russian Federation)
2013-10-07
We explore the quark-mass dependence of the pole position of the X(3872) state within the molecular picture. The calculations are performed within the framework of a nonrelativistic Faddeev-type three-body equation for the DD{sup ¯}π system in the J{sup PC}=1{sup ++} channel. The πD interaction is parametrised via a D{sup ⁎} pole, and a three-body force is included to render the equations well defined. Its strength is adjusted such that the X(3872) appears as a DD{sup ¯⁎} bound state 0.5 MeV below the neutral threshold. We find that the trajectory of the X(3872) depends strongly on the assumed quark-mass dependence of the short-range interactions which can be determined in future lattice QCD calculations. At the same time we are able to provide nontrivial information on the chiral extrapolation in the X channel.
Hadron Spectra and Quark Mass Dependence in Holographic QCD
Hashimoto, K.
Hadron masses and their quark-mass dependence are imporatant observablesin strongly coupled QCD. We apply holography, a string theory technique, to this problem, and find a qualitative coincidence with observed data of baryon spectra. This talk, presented on 9th Feruary 2010 in ``NFQCD'' workshop at YITP, is based on three papers written with my collaborators [K.~Hashimoto, T.~Hirayama, F.~L.~Lin and H.~U.~Yee, J. High Energy Phys. 07 (2008), 089, arXiv:0803.4192. K.~Hashimoto, T.~Hirayama and D.~K.~Hong, Phys. Rev. D 81 (2010), 045016, arXiv:0906.0402. K.~Hashimoto, N.~Iizuka, T.~Ishii and D.~Kadoh, Phys. Lett. B 691 (2010), 65, arXiv:0910.1179.
Kuentz, M
2003-01-01
A two-dimensional lattice gas automaton (LGA) is used for simulating concentration-dependent diffusion in a microscopically random heterogeneous structure. The heterogeneous medium is initialized at a low density rho sub 0 and then submitted to a steep concentration gradient by continuous injection of particles at a concentration rho sub 1 >rho sub 0 from a one-dimensional source to model spreading of a density front. Whereas the nonlinear diffusion equation generally used to describe concentration-dependent diffusion processes predicts a scaling law of the type phi = xt sup - sup 1 sup / sup 2 in one dimension, the spreading process is shown to deviate from the expected t sup 1 sup / sup 2 scaling. The time exponent is found to be larger than 1/2, i.e. diffusion of the density front is enhanced with respect to standard Fickian diffusion. It is also established that the anomalous time exponent decreases as time elapses: anomalous spreading is thus not a timescaling process. We demonstrate that occurrence of a...
Gunawardhana, M L P; Sharp, R G; Brough, S; Taylor, E; Bland-Hawthorn, J; Maraston, C; Tuffs, R J; Popescu, C C; Wijesinghe, D; Jones, D H; Croom, S; Sadler, E; Wilkins, S; Driver, S P; Liske, J; Norberg, P; Baldry, I K; Bamford, S P; Loveday, J; Peacock, J A; Robotham, A S G; Zucker, D B; Parker, Q A; Conselice, C J; Cameron, E; Frenk, C S; Hill, D T; Kelvin, L S; Kuijken, K; Madore, B F; Nichol, B; Parkinson, H R; Pimbblet, K A; Prescott, M; Sutherland, W J; Thomas, D; van Kampen, E
2011-01-01
The stellar initial mass function (IMF) describes the distribution in stellar masses produced from a burst of star formation. For more than fifty years, the implicit assumption underpinning most areas of research involving the IMF has been that it is universal, regardless of time and environment. We measure the high-mass IMF slope for a sample of low-to-moderate redshift galaxies from the Galaxy And Mass Assembly survey. The large range in luminosities and galaxy masses of the sample permits the exploration of underlying IMF dependencies. A strong IMF-star formation rate dependency is discovered, which shows that highly star forming galaxies form proportionally more massive stars (they have IMFs with flatter power-law slopes) than galaxies with low star formation rates. This has a significant impact on a wide variety of galaxy evolution studies, all of which rely on assumptions about the slope of the IMF. Our result is supported by, and provides an explanation for, the results of numerous recent explorations ...
RESOLVE and ECO: The Halo Mass-dependent Shape of Galaxy Stellar and Baryonic Mass Functions
Eckert, Kathleen D.; Kannappan, Sheila J.; Stark, David V.; Moffett, Amanda J.; Berlind, Andreas A.; Norris, Mark A.
2016-06-01
In this work, we present galaxy stellar and baryonic (stars plus cold gas) mass functions (SMF and BMF) and their halo mass dependence for two volume-limited data sets. The first, RESOLVE-B, coincides with the Stripe 82 footprint and is extremely complete down to baryonic mass M bary ∼ 109.1 M ⊙, probing the gas-rich dwarf regime below M bary ∼ 1010 M ⊙. The second, ECO, covers a ∼40× larger volume (containing RESOLVE-A) and is complete to M bary ∼ 109.4 M ⊙. To construct the SMF and BMF we implement a new “cross-bin sampling” technique with Monte Carlo sampling from the full likelihood distributions of stellar or baryonic mass. Our SMFs exhibit the “plateau” feature starting below M star ∼ 1010 M ⊙ that has been described in prior work. However, the BMF fills in this feature and rises as a straight power law below ∼1010 M ⊙, as gas-dominated galaxies become the majority of the population. Nonetheless, the low-mass slope of the BMF is not as steep as that of the theoretical dark matter halo MF. Moreover, we assign group halo masses by abundance matching, finding that the SMF and BMF, separated into four physically motivated halo mass regimes, reveal complex structure underlying the simple shape of the overall MFs. In particular, the satellite MFs are depressed below the central galaxy MF “humps” in groups with mass <1013.5 M ⊙ yet rise steeply in clusters. Our results suggest that satellite destruction and stripping are active from the point of nascent group formation. We show that the key role of groups in shaping MFs enables reconstruction of a given survey’s SMF or BMF based on its group halo mass distribution.
The dependence of the nucleon mass on the pion mass in the extended quark sigma model
The dependence of the nucleon mass on the pion mass is studied in the framework of the extended quark sigma model. We apply the modified quark sigma model to analyze the pion–nucleon sigma term. Analytic expressions are derived using the Feynman–Hellman theorem. The field equations are solved in the mean-field approximation. The results are compared with the CP-PACS group and the cloudy bag model. The results indicate that the extended linear sigma model provides good agreement compared to other models in the mean-field approximation. (author)
Lapas, Luciano C., E-mail: luciano.lapas@unila.edu.br [Universidade Federal da Integração Latino-Americana, Caixa Postal 2067, 85867-970 Foz do Iguaçu, Paraná (Brazil); Ferreira, Rogelma M. S., E-mail: rogelma.maria@gmail.com [Centro de Ciências Exatas e Tecnológicas, Universidade Federal do Recôncavo da Bahia, 44380-000 Cruz das Almas, Bahia (Brazil); Rubí, J. Miguel, E-mail: mrubi@ub.edu [Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Av. Diagonal 647, 08028 Barcelona (Spain); Oliveira, Fernando A., E-mail: fernando.oliveira@pq.cnpq.br [Instituto de Física and Centro Internacional de Física da Matéria Condensada, Universidade de Brasília, Caixa Postal 04513, 70919-970 Brasília, Distrito Federal (Brazil)
2015-03-14
We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton’s law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.
We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton’s law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics
Lapas, Luciano C.; Ferreira, Rogelma M. S.; Rubí, J. Miguel; Oliveira, Fernando A.
2015-03-01
We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.
Mass-dependence of self-diffusion coefficients in disparate-mass binary fluid mixtures
I. Binas
2009-01-01
Full Text Available Self-diffusion coefficients of a binary fluid mixture with components differing only in their particle masses are studied, in particular the case when mass ratio μ of light and heavy particles tends to zero. These coefficients were calculated within the memory function formalism, using the systematic subsequence of approximations for the relaxation times of velocity autocorrelation function. We obtained a general relation for the self-diffusion coefficients which show polynomial dependence on the mass ratio μ. The obtained expression has a correct Brownian limit. We developed the hierarchy of approximations for the self-diffusion coefficients that tends to an exact result from above and below when the order of approximations increases.
Yang, Yongzhang; Li, Zhengxin; Ping, Jinsong
2012-08-01
The relation between the gravity changes and the plumb line variations on ground, in case of the presentation of an anomalous mass underground is stud ied theoretically, formulas are figured out, including the one which describes the relation between the gravity change and the plumb line variation in a more simple way. In a simulation the actual precision of the obtained result is estimated, while the gr avity data of the West Yunnan gravity network, China is also used for the same purpose at the same time. Additionally, by taking use data of this network (32 batches during 1985 - 1998), we analyzed the obtained results of plumb line variation determined at certain sites, and found the similar phenomena which have been reported previously for the Northern China area.
RESOLVE and ECO: The Halo Mass-Dependent Shape of Galaxy Stellar and Baryonic Mass Functions
Eckert, Kathleen D; Stark, David V; Moffett, Amanda J; Berlind, Andreas A; Norris, Mark A
2016-01-01
In this work, we present galaxy stellar and baryonic (stars plus cold gas) mass functions (SMF and BMF) and their halo mass dependence for two volume-limited data sets. The first, RESOLVE-B, coincides with the Stripe 82 footprint and is extremely complete down to baryonic mass Mbary ~ 10^9.1 Msun, probing the gas-rich dwarf regime below Mbary ~ 10^10 Msun. The second, ECO, covers a ~40 times larger volume (containing RESOLVE-A) and is complete to Mbary ~ 10^9.4 Msun. To construct the SMF and BMF we implement a new "cross-bin sampling" technique with Monte Carlo sampling from the full likelihood distributions of stellar or baryonic mass. Our SMFs exhibit the "plateau" feature starting below Mstar ~ 10^10 Msun that has been described in prior work. However, the BMF fills in this feature and rises as a straight power law below ~10^10 Msun, as gas-dominated galaxies become the majority of the population. Nonetheless, the low-mass slope of the BMF is not as steep as that of the theoretical dark matter halo MF. Mor...
Data dependent systems methodology for lumped mass modeling of structures
Pandit, Sudhakar M.
1988-01-01
Limitations of the frequency domain methods in analyzing structura1 vibrations has created an awareness of the comparative merits of the time domain methods. Although time domain methods would be ideal for modeling large precisions space systems, the popular methods based on fitting theoretical response to actual data by least squares are too sensitive to noise and require too much data to be suitable for orbiting space crafts. This paper briefly reviews the theory and illustrative applications of a time domain methodology called Data Dependent Systems (DDS) that eliminates these limitations. Simulation results are presented to demonstrate a better than 4-place accuracy in the identifications of all system parameters, both modal (frequencies, damping ratios, and mode shapes) and physical (mass, stiffness, and damping matrices).
Superintegrable and shape invariant systems with position dependent mass
Second order integrals of motion for 3d quantum mechanical systems with position dependent masses (PDM) are classified. Namely, all PDM systems are specified which, in addition to their rotation invariance, admit at least 1 second order integral of motion. All such systems appear to be also shape invariant and exactly solvable. Moreover, some of them possess the property of double shape invariance and can be solved using two different superpotentials. Among them there are systems with double shape invariance which present nice bridges between the Coulomb and isotropic oscillator systems. A simple algorithm for calculating the discrete spectrum and the corresponding state vectors for the considered PDM systems is presented and applied to solve five of the found systems. (paper)
How Lyman Alpha Emission Depends On Galaxy Stellar Mass
Oyarzún, Grecco A; González, Valentino; Mateo, Mario; Bailey, John I; Finkelstein, Steven L; Lira, Paulina; Crane, Jeffrey D; Olszewski, Edward W
2016-01-01
In this work, we show how the stellar mass (M) of galaxies affects the 3
Unparticles and anomalous dimensions in the cuprates
Karch, Andreas; Limtragool, Kridsanaphong; Phillips, Philip W.
2016-03-01
Motivated by the overwhelming evidence some type of quantum criticality underlies the power-law for the optical conductivity and T-linear resistivity in the cuprates, we demonstrate here how a scale-invariant or unparticle sector can lead to a unifying description of the observed scaling forms. We adopt the continuous mass formalism or multi band (flavor) formalism of the unparticle sector by letting various microscopic parameters be mass-dependent. In particular, we show that an effective mass that varies with the flavor index as well as a running band edge and lifetime capture the AC and DC transport phenomenology of the cuprates. A key consequence of the running mass is that the effective dynamical exponent can differ from the underlying bare critical exponent, thereby providing a mechanism for realizing the fractional values of the dynamical exponent required in a previous analysis [1]. We also predict that regardless of the bare dynamical exponent, z, a non-zero anomalous dimension for the current is required. Physically, the anomalous dimension arises because the charge depends on the flavor, mass or energy. The equivalent phenomenon in a d + 1 gravitational construction is the running of the charge along the radial direction. The nature of the superconducting instability in the presence of scale invariant stuff shows that the transition temperature is not necessarily a monotonic function of the pairing interaction.
Position-dependent mass quantum Hamiltonians: general approach and duality
We analyze a general family of position-dependent mass (PDM) quantum Hamiltonians which are not self-adjoint and include, as particular cases, some Hamiltonians obtained in phenomenological approaches to condensed matter physics. We build a general family of self-adjoint Hamiltonians which are quantum mechanically equivalent to the non-self-adjoint proposed ones. Inspired by the probability density of the problem, we construct an ansatz for the solutions of the family of self-adjoint Hamiltonians. We use this ansatz to map the solutions of the time independent Schrödinger equations generated by the non-self-adjoint Hamiltonians into the Hilbert space of the solutions of the respective dual self-adjoint Hamiltonians. This mapping depends on both the PDM and on a function of position satisfying a condition that assures the existence of a consistent continuity equation. We identify the non-self-adjoint Hamiltonians here studied with a very general family of Hamiltonians proposed in a seminal article of Harrison (1961 Phys. Rev. 123 85) to describe varying band structures in different types of metals. Therefore, we have self-adjoint Hamiltonians that correspond to the non-self-adjoint ones found in Harrison’s article. (paper)
Gabor, M. S.; Petrisor, T.; Pop, O.; Colis, S.; Tiusan, C.
2015-10-01
We report a detailed study of the temperature dependence of the magnetic anisotropy in Ta/Co2FeAl/MgO structures by means of Anomalous Hall Effect measurements. The volume magnetic anisotropy, although negligible at room temperature, shows a non-negligible value at low temperatures and favors an in-plane easy magnetization axis. The surface magnetic anisotropy, which promotes the perpendicular magnetic easy axis, shows an increase from 0.76 ± 0.05 erg /cm2 at 300 K, up to 1.08 ± 0.04 erg /cm2 at 5 K, attributed to the evolution of the Co2FeAl layer saturation magnetization with temperature.
A stellar-mass-dependent drop in planet occurrence rates
Mulders, Gijs D; Apai, Daniel
2014-01-01
The Kepler Space Telescope has discovered a large number of planets up to one year periods and down to terrestrial sizes. The cool star subsample allows characterization of small planets near the habitable zone, yet it is not clear if this population is representative of that around sun-like stars. In this paper, we show that occurrence rates of planets around M, K, G, and F stars observed with Kepler are significantly different from each other. We identify two trends with stellar mass: First, the occurrence of Earth to Neptune-sized planets (1 to 4 Earth radii) is successively higher towards cooler stars at all orbital periods probed by Kepler, confirming the result of Howard et al. (2012) and extending it down to Earth-sized planets; Second, a drop in occurrence rates towards the star is evident for all spectral types inwards of a ~10 day orbital period, with a plateau further out. The distance from the star where this drop occurs depends on spectral type, and scales with semi-major axis as the cube root of...
Microbial mass-dependent fractionation of chromium isotopes
Sikora, E.R.; Johnson, T.M.; Bullen, T.D.
2008-01-01
Mass-dependent fractionation of Cr isotopes occurs during dissimilatory Cr(VI) reduction by Shewanella oneidensis strain MR-1. Cells suspended in a simple buffer solution, with various concentrations of lactate or formate added as electron donor, reduced 5 or 10 ??M Cr(VI) to Cr(III) over days to weeks. In all nine batch experiments, 53Cr/52Cr ratios of the unreacted Cr(VI) increased as reduction proceeded. In eight experiments covering a range of added donor concentrations up to 100 ??M, isotopic fractionation factors were nearly invariant, ranging from 1.0040 to 1.0045, with a mean value somewhat larger than that previously reported for abiotic Cr(VI) reduction (1.0034). One experiment containing much greater donor concentration (10 mM lactate) reduced Cr(VI) much faster and exhibited a lesser fractionation factor (1.0018). These results indicate that 53Cr/52Cr measurements should be effective as indicators of Cr(VI) reduction, either bacterial or abiotic. However, variability in the fractionation factor is poorly constrained and should be studied for a variety of microbial and abiotic reduction pathways. ?? 2008 Elsevier Ltd.
Position-dependent mass, finite-gap systems, and supersymmetry
Bravo, Rafael
2016-01-01
The ordering problem in quantum systems with position-dependent mass (PDM) is treated by inclusion of the classically fictitious similarity transformation into the kinetic term. This provides a generation of supersymmetry with the first order supercharges from the kinetic term alone, while inclusion of the potential term allows to generate also nonlinear supersymmetry with higher order supercharges. A broad class of finite-gap systems with PDM is obtained by different reduction procedures, and general results on supersymmetry generation are applied to them. We show that elliptic finite-gap systems of Lame and Darboux-Treibich-Verdier types can be obtained by reduction to Seiffert's spherical spiral and Bernoulli lemniscate in the presence of Calogero-like or harmonic oscillator potentials, or by angular momentum reduction of a free motion on some AdS_2-related surfaces in the presence of Aharonov-Bohm flux. The limiting cases include the Higgs and Mathews-Lakshmanan oscillator models as well as a reflectionle...
Position-dependent mass, finite-gap systems, and supersymmetry
Bravo, Rafael; Plyushchay, Mikhail S.
2016-05-01
The ordering problem in quantum systems with position-dependent mass (PDM) is treated by inclusion of the classically fictitious similarity transformation into the kinetic term. This provides a generation of supersymmetry with the first-order supercharges from the kinetic term alone, while inclusion of the potential term allows us also to generate nonlinear supersymmetry with higher-order supercharges. A broad class of finite-gap systems with PDM is obtained by different reduction procedures, and general results on supersymmetry generation are applied to them. We show that elliptic finite-gap systems of Lamé and Darboux-Treibich-Verdier types can be obtained by reduction to Seiffert's spherical spiral and Bernoulli lemniscate in the presence of Calogero-like or harmonic oscillator potentials, or by angular momentum reduction of a free motion on some AdS2 -related surfaces in the presence of Aharonov-Bohm flux. The limiting cases include the Higgs and Mathews-Lakshmanan oscillator models as well as a reflectionless model with PDM exploited recently in the discussion of cosmological inflationary scenarios.
Galaxy Mergers and Dark Matter Halo Mergers in LCDM: Mass, Redshift, and Mass-Ratio Dependence
Stewart, Kyle R.; Bullock, James S.; Barton, Elizabeth J.; /UC, Irvine; Wechsler, Risa H.; /KIPAC, Menlo Park /SLAC
2009-08-03
We employ a high-resolution LCDM N-body simulation to present merger rate predictions for dark matter halos and investigate how common merger-related observables for galaxies - such as close pair counts, starburst counts, and the morphologically disturbed fraction - likely scale with luminosity, stellar mass, merger mass ratio, and redshift from z = 0 to z = 4. We provide a simple 'universal' fitting formula that describes our derived merger rates for dark matter halos a function of dark halo mass, merger mass ratio, and redshift, and go on to predict galaxy merger rates using number density-matching to associate halos with galaxies. For example, we find that the instantaneous merger rate of m/M > 0.3 mass ratio events into typical L {approx}> fL{sub *} galaxies follows the simple relation dN/dt {approx_equal} 0.03(1+f)Gyr{sup -1} (1+z){sup 2.1}. Despite the rapid increase in merger rate with redshift, only a small fraction of > 0.4L{sub *} high-redshift galaxies ({approx} 3% at z = 2) should have experienced a major merger (m/M > 0.3) in the very recent past (t < 100 Myr). This suggests that short-lived, merger-induced bursts of star formation should not contribute significantly to the global star formation rate at early times, in agreement with observational indications. In contrast, a fairly high fraction ({approx} 20%) of those z = 2 galaxies should have experienced a morphologically transformative merger within a virial dynamical time. We compare our results to observational merger rate estimates from both morphological indicators and pair-fraction based determinations between z = 0-2 and show that they are consistent with our predictions. However, we emphasize that great care must be made in these comparisons because the predicted observables depend very sensitively on galaxy luminosity, redshift, overall mass ratio, and uncertain relaxation timescales for merger remnants. We show that the majority of bright galaxies at z = 3 should have undergone a
We use recent experimental measurements of tau branching fractions to determine the weak charged current magnetic and electric dipole moments of the tau and the Michel parameter η with unprecedented precision. These results are then used to constrain the tau compositeness scale and the allowed parameter space for Higgs doublet models. We also present new constraints on the mass of the tau neutrino and its mixing with a fourth generation neutrino
We study electron hopping in thin metal-insulator-metal structures which involves two defect centres with a strong electron-phonon coupling. We calculate the dependences of the current, J, on voltage, V, and temperature, T, and show that they are consistent with those observed in molecular monolayers of fatty acids. We analyse in detail an unusual, near-exponential temperature dependence of the current: J(T) ∝ exp (T/T0) T ≥ 50 K in eicosanoic acid (C20) organic monolayers sandwiched between Pt electrodes, where the parameter T0 increases with the bias voltage. We show that at relatively high voltages the two-defect small-polaron hopping results in N-shape current-voltage characteristics which were observed in some organic molecular monolayers
Biswas, Anirban; Choubey, Sandhya; Khan, Sarif
2016-01-01
The observation of neutrino masses, mixing and the existence of dark matter are amongst the most important signatures of physics beyond the Standard Model (SM). In this paper, we propose to extend the SM by a local $L_\\mu - L_\\tau$ gauge symmetry, two additional complex scalars and three right-handed neutrinos. The $L_\\mu - L_\\tau$ gauge symmetry is broken spontaneously when one of the scalars acquires a vacuum expectation value. The $L_\\mu - L_\\tau$ gauge symmetry is known to be anomaly free...
Compositions of Normal and Anomalous Eucrite-Type Mafic Achondrites
Mittlefehldt, D. W.; Peng, Z. X.; Mertzman, S. A.
2016-01-01
The most common asteroidal igneous meteorites are eucrite-type mafic achondrites - basalts and gabbros composed of ferroan pigeonite, ferroan augite, calcic plagioclase, silica, ilmenite, troilite, Ca-phosphate, chromite and Fe-metal. These rocks are thought to have formed on a single asteroid along with howardites and diogenites. However, high precision O-isotopic analyses have shown that some mafic achondrites have small, well-resolved, non-mass-dependent differences that have been interpreted as indicating derivation from different asteroids. Some of these O-anomalous mafic achondrites also have anomalous petrologic characteristics, strengthening the case that they hail from distinct parent asteroids. We present the results of bulk compositional studies of a suite of normal and anomalous eucrite-type basalts and cumulate gabbros.
Jia, Lian-Bao
2016-01-01
The WIMPs are considered one of the most favorable dark matter (DM) candidates, but as the upper bound on the interaction between DM and standard model (SM) particles obtained by the upgraded facilities for direct detection of DM gets lower and lower. Researchers turn their attention to search for less massive DM candidates, i.e. light dark matter of MeV scale. The recently measured anomalous transition in $^8$Be suggests that there exists a vectorial boson which may mediate the interaction between DM and SM particles. Based on this scenario, we combine the relevant cosmological data to constrain the mass range of DM, and have found that there exists a model parameter space where the requirements are satisfied, a range of $10.4 \\lesssim m_{\\phi} \\lesssim 16.7 $ MeV for scalar DM, and $13.6 \\lesssim m_{V} \\lesssim 16.7$ MeV for vectorial DM is demanded. Then a possibility of directly detecting such light DM particles at the earth detector via the DM-electron scattering is briefly studied in this framework.
Dependence of lattice hadron masses on external magnetic fields
We study the variation of the hadron masses in the presence of external magnetic fields of strength of the order of the masses themselves. We identify the main factors affecting the lattice simulation results: - The boundary discontinuities for eB2a2. - The SU(6) choice of the hadron wave-function. We confirm qualitatively the earlier theoretical ansatz on the linear behaviour of the masses with the magnetic field and, as a by-product, we improve the lattice measurements of the nucleon magnetic moments. However our systematic and statistical errors preclude us from measuring the theoretically predicted field strength at which the proton becomes heavier than the neutron. (orig.)
Charm quark mass dependence in a global QCD analysis
Gao, Jun; Guzzi, Marco; Nadolsky, Pavel M.
2013-01-01
We study the effect of the charm quark mass in the CTEQ global analysis of parton distribution functions (PDFs) of the proton. Constraints on the $\\bar{\\rm MS}$ mass of the charm quark are examined at the next-to-next-to-leading order (NNLO) accuracy in the S-ACOT-$\\chi$ heavy-quark factorization scheme. The value of the charm quark mass from the hadronic scattering data in the CT10 NNLO fit, including semiinclusive charm production in DIS at HERA collider, is found to agree with the world av...
Role of isospin degree of freedom on the mass dependence of balance energy
Gautam, Sakshi; Sood, Aman D.
2010-01-01
The effect of isospin degree of freedom on balance energy and its mass dependence has been studied for the mass range between 50 and 350. Our results shows the dominance of Coulomb potential in isospin effects.
Is the Binary Mass Ratio Distribution Separation-Dependent?
Gullikson, Kevin; Kraus, Adam L.
2016-01-01
Recent discoveries of planets orbiting retired A-stars on close orbits and young A-stars on very wide orbits have renewed interest in the properties of nearby intermediate-mass stars. Especially interesting are the young stars because directly-imaged planets orbiting them may be bright enough for characterization (e.g. HR 8799, Beta Pictoris, etc). However, intermediate-mass stars and especially young intermediate mass stars are part of multiple systems more often than not. Close stellar companions may affect the formation and orbital evolution of any planets, and the properties of the companions can help constrain the binary formation mechanism. The mass ratio distribution of a population of binary stars, especially if the distribution for close companions is significantly different from that of wide companions, is helpful to distinguish companions that were born in or affected by the circumstellar disk from those which formed through fragmentation of the molecular core. Previous imaging surveys have found that binary systems with A-type primary stars tend to have cool companions with extreme mass ratios. There are hints at a much flatter mass ratio distribution for close companions, but strong completeness effects complicate the picture. We have conducted a spectroscopic survey of ~400 nearby main sequence A- and B-type stars, aimed at detecting stellar companions as late as M4 for all orbital separations stars by cross-correlating the spectra against model templates for F-M type stars; a significant peak in the cross-correlation function indicates a detection. Our cross-correlation technique can detect low-mass companions with orbits that are too wide to detect with radial velocity monitoring and too small to detect with imaging techniques, making it complementary to work already done. We will present results from our survey and compare the mass ratio distribution we measure to the corresponding distribution for wide companions.
The mass dependence of dwarf satellite galaxy quenching
We combine observations of the Local Group with data from the NASA-Sloan Atlas to show the variation in the quenched fraction of satellite galaxies from low-mass dwarf spheroidals and dwarf irregulars to more massive dwarfs similar to the Magellanic Clouds. While almost all of the low-mass (M * ≲ 107 M ☉) dwarfs are quenched, at higher masses the quenched fraction decreases to approximately 40%-50%. This change in the quenched fraction is large and suggests a sudden change in the effectiveness of quenching that correlates with satellite mass. We combine this observation with models of satellite infall and ram pressure stripping to show that the low-mass satellites must quench within 1-2 Gyr of pericenter passage to maintain a high quenched fraction, but that many more massive dwarfs must continue to form stars today even though they likely fell into their host >5 Gyr ago. We also characterize how the susceptibility of dwarfs to ram pressure must vary as a function of mass if it is to account for the change in quenched fractions. Though neither model predicts the quenching effectiveness a priori, this modeling illustrates the physical requirements that the observed quenched fractions place on possible quenching mechanisms.
The Mass Dependence of Dwarf Satellite Galaxy Quenching
Slater, Colin T
2014-01-01
We combine observations of the Local Group with data from the NASA-Sloan Atlas to show the variation in the quenched fraction of satellite galaxies from low mass dwarf spheroidals and dwarf irregulars to more massive dwarfs similar to the Magellanic clouds. While almost all of the low mass ($M_\\star \\lesssim 10^7$ $M_\\odot$) dwarfs are quenched, at higher masses the quenched fraction decreases to approximately 40-50%. This change in the quenched fraction is large, and suggests a sudden change in the effectiveness of quenching that correlates with satellite mass. We combine this observation with models of satellite infall and ram pressure stripping to show that the low mass satellites must quench within 1-2 Gyr of pericenter passage to maintain a high quenched fraction, but that many more massive dwarfs must continue to form stars today even though they likely fell in to their host >5 Gyr ago. We also characterize how the susceptibility of dwarfs to ram pressure must vary as a function of mass if it is to acco...
The mass dependence of dwarf satellite galaxy quenching
Slater, Colin T.; Bell, Eric F., E-mail: ctslater@umich.edu, E-mail: ericbell@umich.edu [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)
2014-09-10
We combine observations of the Local Group with data from the NASA-Sloan Atlas to show the variation in the quenched fraction of satellite galaxies from low-mass dwarf spheroidals and dwarf irregulars to more massive dwarfs similar to the Magellanic Clouds. While almost all of the low-mass (M {sub *} ≲ 10{sup 7} M {sub ☉}) dwarfs are quenched, at higher masses the quenched fraction decreases to approximately 40%-50%. This change in the quenched fraction is large and suggests a sudden change in the effectiveness of quenching that correlates with satellite mass. We combine this observation with models of satellite infall and ram pressure stripping to show that the low-mass satellites must quench within 1-2 Gyr of pericenter passage to maintain a high quenched fraction, but that many more massive dwarfs must continue to form stars today even though they likely fell into their host >5 Gyr ago. We also characterize how the susceptibility of dwarfs to ram pressure must vary as a function of mass if it is to account for the change in quenched fractions. Though neither model predicts the quenching effectiveness a priori, this modeling illustrates the physical requirements that the observed quenched fractions place on possible quenching mechanisms.
Mass Dependence of the Entropy Product and Sum
Zhang, Yuan
2014-01-01
For black holes with multiple horizons, the area product of all horizons has been proven to be mass independent in many cases. Counterexamples were also found in some occasions. In this paper, we first prove a theorem derived from the first law of black hole thermodynamics and a mathematical lemma related to the Vandermonde determinant. With these arguments, we develop some general criterion for the mass independence of the entropy product as well as the entropy sum. In particular, if a $d$-dimensional spacetime is spherically symmetric and its the radial metric function $f(r)$ is a Laurent series in $r$ with the lowest power $-m$ and the highest power $n$, we find the criteria is extremely simple: The entropy product is mass independent if and only if $m\\geq d-2$ and $n\\geq4-d$. The entropy sum is mass independent if and only if $m\\geq d-2$ and $n\\geq 2$. Compared to previous works, our method does not require an exact expression of the metric. Our arguments turn out to be useful even for rotating black hole...
Nonlocal Anomalous Hall Effect
Zhang, Steven S.-L.; Vignale, Giovanni
2016-04-01
The anomalous Hall (AH) effect is deemed to be a unique transport property of ferromagnetic metals, caused by the concerted action of spin polarization and spin-orbit coupling. Nevertheless, recent experiments have shown that the effect also occurs in a nonmagnetic metal (Pt) in contact with a magnetic insulator [yttrium iron garnet (YIG)], even when precautions are taken to ensure that there is no induced magnetization in the metal. We propose a theory of this effect based on the combined action of spin-dependent scattering from the magnetic interface and the spin-Hall effect in the bulk of the metal. At variance with previous theories, we predict the effect to be of first order in the spin-orbit coupling, just as the conventional anomalous Hall effect—the only difference being the spatial separation of the spin-orbit interaction and the magnetization. For this reason we name this effect the nonlocal anomalous Hall effect and predict that its sign will be determined by the sign of the spin-Hall angle in the metal. The AH conductivity that we calculate from our theory is in order of magnitude agreement with the measured values in Pt /YIG structures.
Mass- and isospin-dependence of short-range correlated pairs
Mosel, U
2016-01-01
The target-mass number dependence of nucleon-nucleon pairs with short-range correlations is explored in a physically transparent geometrical model. The observed $A$-dependence of 2-nucleon ejection cross sections in $(e,e')$ reactions is found to reflect the mass-dependence of nuclear density distributions. The dependence of proton-proton vs. proton-neutron pairs is also analyzed in this model. The mass-number dependence relative to $^{12}C$ can be understood using simple combinatorics.
On the quark-mass dependence of baryon ground-state masses
Semke, Alexander
2010-02-17
Baryon masses of the flavour SU(3) octet and decuplet baryons are calculated in the framework of the Chiral Perturbations Theory - the effective field theory of the strong interaction. The chiral extrapolation to the higher meson (quark) masses is carried out. The comparison with the recent results on the baryon masses from lattice calculations are presented. (orig.)
On the quark-mass dependence of baryon ground-state masses
Baryon masses of the flavour SU(3) octet and decuplet baryons are calculated in the framework of the Chiral Perturbations Theory - the effective field theory of the strong interaction. The chiral extrapolation to the higher meson (quark) masses is carried out. The comparison with the recent results on the baryon masses from lattice calculations are presented. (orig.)
Axel Schulze-Halberg
2005-01-01
We study space-time transformations of the time-dependent Schr(o)dinger equation (TDSE) with time- and position-dependent (effective) mass. We obtain the most general space-time transformation that maps such a TDSE onto another one of its kind. The transformed potential is given in explicit form.
THE MASS DEPENDENCE BETWEEN PROTOPLANETARY DISKS AND THEIR STELLAR HOSTS
We present a substantial extension of the millimeter (mm) wave continuum photometry catalog for circumstellar dust disks in the Taurus star-forming region, based on a new ''snapshot'' λ = 1.3 mm survey with the Submillimeter Array. Combining these new data with measurements in the literature, we construct a mm-wave luminosity distribution, f(Lmm), for Class II disks that is statistically complete for stellar hosts with spectral types earlier than M8.5 and has a 3σ depth of roughly 3 mJy. The resulting census eliminates a longstanding selection bias against disks with late-type hosts, and thereby demonstrates that there is a strong correlation between Lmm and the host spectral type. By translating the locations of individual stars in the Hertzsprung-Russell diagram into masses and ages, and adopting a simple conversion between Lmm and the disk mass, Md , we confirm that this correlation corresponds to a statistically robust relationship between the masses of dust disks and the stars that host them. A Bayesian regression technique is used to characterize these relationships in the presence of measurement errors, data censoring, and significant intrinsic scatter: the best-fit results indicate a typical 1.3 mm flux density of ∼25 mJy for 1 M☉ hosts and a power-law scaling Lmm∝M*1.5-2.0. We suggest that a reasonable treatment of dust temperature in the conversion from Lmm to Md favors an inherently linear Md ∝M* scaling, with a typical disk-to-star mass ratio of ∼0.2%-0.6%. The measured rms dispersion around this regression curve is ±0.7 dex, suggesting that the combined effects of diverse evolutionary states, dust opacities, and temperatures in these disks imprint a full width at half-maximum range of a factor of ∼40 on the inferred Md (or Lmm) at any given host mass. We argue that this relationship between Md and M* likely represents the origin of the inferred correlation between giant planet frequency and host star mass in the exoplanet population, and
QCD One-Loop Effective Coupling Constant and Quark Mass Given in a Mass-Dependent Renormalization
SU Jun-Chen; SHAN Lian-You; CAO Ying-Hui
2001-01-01
The QCD one-loop renormalization is restudied in a mass-dependent subtraction scheme in which the quark mass is not set to vanish and the renormalization point is chosen to be an arbitrary time-like momentum. The correctness of the subtraction is ensured by the Ward identities which are respected in all the processes of subtraction.By considering the mass effect, the effective coupling constant and the effective quark masses derived by solving the renormalization group equations are given in improved expressions which are different from the previous results.PACS numbers: 11.10.Gh, 11.10.Hi, 12.38.-t, 12.38.Bx
Quark Mass Dependence of Nucleon Magnetic Moment and Charge Radii
MA Wei-Xing; ZHOU Li-Juan; GU Yun-Ting; PING Rong-Gang
2005-01-01
Understanding hadron structure within the framework of QCD is an extremely challenging problem. Our purpose here is to explain the model-independent consequences of the approximated chiral symmetry of QCD for two famous results concerning the quark structure of the nucleon. We show that both the apparent success of the constituent quark model in reproducing the ratio of proton to neutron magnetic moments and the apparent success of the Foldy term in reproducing the observed charge radius of the neutron are coincidental. That is, a relatively small change of the current quark mass would spoil both results.
Isospin dependence of nucleon effective masses in neutron-rich matter
Li, Bao-An; Chen, Lie-Wen; Li, Xiao-Hua
2016-01-01
In this talk, we first briefly review the isospin dependence of the total nucleon effective mass $M^{\\ast}_{J}$ inferred from analyzing nucleon-nucleus scattering data within an isospin dependent non-relativistic optical potential model, and the isospin dependence of the nucleon E-mass $M^{\\ast,\\rm{E}}_{J}$ obtained from applying the Migdal-Luttinger theorem to a phenomenological single-nucleon momentum distribution in nuclei constrained by recent electron-nucleus scattering experiments. Combining information about the isospin dependence of both the nucleon total effective mass and E-mass, we then infer the isospin dependence of nucleon k-mass using the well-known relation $M^{\\ast}_{J}=M^{\\ast,\\rm{E}}_{J}\\cdot M^{\\ast,\\rm{k}}_{J}$. Implications of the results on the nucleon mean free path (MFP) in neutron-rich matter are discussed.
Ladder operators and associated algebra for position-dependent effective mass systems
Amir, Naila; Iqbal, Shahid
2015-07-01
An algebraic treatment of shape-invariant quantum-mechanical position-dependent effective mass systems is discussed. Using shape invariance, a general recipe for construction of ladder operators and associated algebraic structure of the pertaining system, is obtained. These operators are used to find exact solutions of general one-dimensional systems with spatially varying mass. We apply our formalism to specific translationally shape-invariant potentials having position-dependent effective mass.
Quark mass density- and temperature- dependent model for bulk strange quark matter
al, Yun Zhang et.
2002-01-01
It is shown that the quark mass density-dependent model can not be used to explain the process of the quark deconfinement phase transition because the quark confinement is permanent in this model. A quark mass density- and temperature-dependent model in which the quark confinement is impermanent has been suggested. We argue that the vacuum energy density B is a function of temperature. The dynamical and thermodynamical properties of bulk strange quark matter for quark mass density- and temper...
Binary accretion rates: dependence on temperature and mass-ratio
Young, Matthew D
2015-01-01
We perform a series of 2D smoothed particle hydrodynamics (SPH) simulations of gas accretion onto binaries via a circumbinary disc, for a range of gas temperatures and binary mass ratios ($q$). We show that increasing the gas temperature increases the accretion rate onto the primary for all values of the binary mass ratio: for example, for $q=0.1$ and a fixed binary separation, an increase of normalised sound speed by a factor of $5$ (from our "cold" to "hot" simulations) changes the fraction of the accreted gas that flows on to the primary from $ 10\\%$ to $\\sim40\\%$. We present a simple parametrisation for the average accretion rate of each binary component accurate to within a few percent and argue that this parametrisation (rather than those in the literature based on warmer simulations) is relevant to supermassive black hole accretion and all but the widest stellar binaries. We present trajectories for the growth of $q$ during circumbinary disc accretion and argue that the period distribution of stellar "...
Anomalous Hall effect in polycrystalline Ni films
Guo, Zaibing
2012-02-01
We systematically studied the anomalous Hall effect in a series of polycrystalline Ni films with thickness ranging from 4 to 200 nm. It is found that both the longitudinal and anomalous Hall resistivity increased greatly as film thickness decreased. This enhancement should be related to the surface scattering. In the ultrathin films (46 nm thick), weak localization corrections to anomalous Hall conductivity were studied. The granular model, taking into account the dominated intergranular tunneling, has been employed to explain this phenomenon, which can explain the weak dependence of anomalous Hall resistivity on longitudinal resistivity as well. © 2011 Elsevier Ltd. All rights reserved.
Spatial dependence of 2MASS luminosity and mass functions in the old open cluster NGC 188
Bonatto, C; Santos, J F C
2005-01-01
Luminosity and mass functions in the old open cluster NGC 188 are analysed by means of J and H 2MASS photometry. Within the uncertainties, the observed projected radial density profile of NGC 188 departs from the two-parameter King model in two inner regions, which reflects the non-virialized dynamical state and possibly, some degree of non-sphericity in the spatial shape of this old open cluster. Fits with two and three-parameter King models to the radial distribution of stars resulted in a core radius of 1.3 pc and a tidal radius of 21 pc. The present 2MASS analysis resulted in significant slope variations with distance in the mass function $\\phi(m)\\propto m^{-(1+\\chi)}$, being flat in the central parts ($\\chi=0.6\\pm0.7$) and steep in the cluster outskirts ($\\chi=7.2\\pm0.6$). The overall mass function has a slope $\\chi=1.9\\pm0.7$, slightly steeper than a standard Salpeter mass function. Solar metallicity Padova isochrone fits to the near-infrared colour-magnitude diagram of NGC 188 resulted in an age of $7....
Semiclassical Method to Schr(o)dinger Equation with Position-Dependent Effective Mass
CHEN Gang; XUAN Pei-Cai; CHEN Zi-Dong
2006-01-01
In this paper, two novel semiclassical methods including the standard and supersymmetric WKB quantization conditions are suggested to discuss the Schrodinger equation with position-dependent effective mass. From a proper coordinate transformation, the formalism of the Schrodinger equation with position-dependent effective mass is mapped into isospectral one with constant mass and therefore for a given mass distribution and physical potential function the bound state energy spectrum can be determined easily by above method associated with a simple integral formula. It is shown that our method can give the analytical results for some exactly-solvable quantum systems.
Generalized Harmonic Oscillator and the Schr(o)dinger Equation with Position-Dependent Mass
JU Guo-Xing; CAI Chang-Ying; REN Zhong-Zhou
2009-01-01
We study the generalized harmonic oscillator that has both the position-dependent mass and the potential depending on the form of mass function in a more general framework. The explicit expressions of the eigenvalue and eigenfunction for such a system are given, they have the same forms as those for the usual harmonic oscillator with constant mass. The coherent state and its properties for the system with PDM are also discussed. We give the corresponding effective potentials for several mass functions, the systems with such potentials are isospectral to the usual harmonic oscillator.
Evolution of low-mass X-ray binaries: dependence on the mass of the compact object
Qian Xu; Tao Li; Xiang-Dong Li
2012-01-01
We perform numerical calculations to simulate the evolution of low-mass X-ray binary systems.For the accreting compact object we consider the initial mass of 1.4,10,20,100,200,500 and 1000 M☉,corresponding to neutron stars (NSs),stellarmass black holes (BHs) and intermediate-mass BHs.Mass transfer in these binaries is driven by nuclear evolution of the donors and/or orbital angular momentum loss due to magnetic braking and gravitational wave radiation.For the different systems,we determine their bifurcation periods Pbif that separate the formation of converging systems from the diverging ones,and show that Pbif changes from ～ 1 d to (≥)3 d for a 1 M☉ donor star,with increasing initial accretor mass from 1.4 to 1000 M☉.This means that the dominant mechanism of orbital angular momentum loss changes from magnetic braking to gravitational radiation.As an illustration we compare the evolution of binaries consisting of a secondary star of 1 M☉ at a fixed initial period of 2 d.In the case of the NS or stellar-mass BH accretor,the system evolves to a well-detached He white dwarf-neutron star/black hole pair,but it evolves to an ultracompact binary if the compact object is an intermediate-mass BH.Thus the binary evolution heavily depends upon the mass of the compact object.However,we show that the final orbital period-white dwarf mass relation found for NS low-mass X-ray binaries is fairly insensitive to the initial mass of the accreting star,even if it is an intermediate-mass BH.
Moments of heavy quark correlators with two masses: exact mass dependence to three loops
Grigo, Jonathan; Marquard, Peter; Steinhauser, Matthias
2012-01-01
We compute moments of non-diagonal correlators with two massive quarks. Results are obtained where no restriction on the ratio of the masses is assumed. Both analytical and numerical methods are applied in order to evaluate the two-scale master integrals at three loops. We provide explicit results for the latter which are useful for other calculations. As a by-product we obtain results for the electroweak $\\rho$ parameter up to three loops which can be applied to a fourth generation of quarks with arbitrary masses.
Effect of mass asymmetry on the mass dependence of balance energy
Goyal, Supriya
2011-01-01
We demonstrate the role of the mass asymmetry on the balance energy (Ebal) by studying asymmetric reactions throughout the periodic table and over entire colliding geometry. Our results, which are almost independent of the system size and as well as of the colliding geometries indicate a sizeable effect of the asymmetry of the reaction on the balance energy.
Temperature dependence of meson screening masses; a comparison of effective model with lattice QCD
Ishii, Masahiro; Kashiwa, Kouji; Kouno, Hiroaki; Yahiro, Masanobu
2015-01-01
Temperature dependence of pion and sigma-meson screening masses is evaluated by the Polyakov-loop extended Nambu--Jona-Lasinio model with the entanglement vertex (EPNJL model). We propose a practical way of calculating meson screening masses in the NJL-type effective models. The method based on the Pauli-Villars regularization solves the well-known difficulty that the evaluation of screening masses is not easy in the NJL-type effective models. The method is applied to analyze temperature dependence of pion screening masses calculated with state-of-the-art lattice simulations with success in reproducing the lattice QCD results. We predict the temperature dependence of pole mass by using EPNJL model.
Determination of the temperature dependence of the up- down-quark mass in QCD
Dominguez, C A
2016-01-01
The temperature dependence of the sum of the QCD up- and down-quark masses, $(m_u + m_d)$ and the pion decay constant, $f_\\pi$, are determined from two thermal finite energy QCD sum rules for the pseudoscalar-current correlator. This quark-mass remains mostly constant for temperatures well below the critical temperature for deconfinement/chiral-symmetry restoration. As this critical temperature is approached, the quark-mass increases sharply with increasing temperature. This increase is far more pronounced if the temperature dependence of the pion mass (determined independently from other methods) is taken into account. The behavior of $f_\\pi(T)$ is consistent with the expectation from chiral symmetry, i.e. that it should follow the thermal dependence of the quark condensate, independently of the quark mass.
Environment-dependent genetic correlations between development time and body mass in a scorpionfly
Engqvist, Leif
2007-01-01
Development time and body mass at maturation are two important fitness traits fundamental for our understanding of life history theory. Generally, fast development is associated with small adult body mass, as it will take longer to grow large. However, the strength of this trade-off may depend on average food availability, as the potential benefit of long development will depend on the rate of food intake. Here, I report results of a food manipulation experiment during larval development of t...
Beane, S R; Detmold, W; Lin, H W; Luu, T C; Orginos, K; Parreno, A; Savage, M J; Torok, A; Walker-Loud, A
2011-07-01
The volume dependence of the octet baryon masses and relations among them are explored with Lattice QCD. Calculations are performed with nf = 2 + 1 clover fermion discretization in four lattice volumes, with spatial extent L ? 2.0, 2.5, 3.0 and 4.0 fm, with an anisotropic lattice spacing of b_s ? 0.123 fm in the spatial direction, and b_t = b_s/3.5 in the time direction, and at a pion mass of m_\\pi ? 390 MeV. The typical precision of the ground-state baryon mass determination is dependence of the masses, the Gell-Mann Okubo mass-relation, and of other mass combinations. A comparison with the predictions of heavy baryon chiral perturbation theory is performed in both the SU(2)L ? SU(2)R and SU(3)L ? SU(3)R expansions. Predictions of the three-flavor expansion for the hadron masses are found to describe the observed volume dependences reasonably well. Further, the ?N? axial coupling constant is extracted from the volume dependence of the nucleon mass in the two-flavor expansion, with only small modifications in the three-flavor expansion from the inclusion of kaons and eta's. At a given value of m?L, the finite-volume contributions to the nucleon mass are predicted to be significantly smaller at m_\\pi ? 140 MeV than at m_\\pi ? 390 MeV due to a coefficient that scales as ? m_\\pi^3. This is relevant for the design of future ensembles of lattice gauge-field configurations. Finally, the volume dependence of the pion and kaon masses are analyzed with two-flavor and three-flavor chiral perturbation theory.
V K Gupta; Asha Gupta; S Singh; J D Anand
2003-10-01
We report on the study of the mass–radius (–) relation and the radial oscillations of magnetized proto strange stars. For the quark matter we have employed the very recent modiﬁcation, the temperature- and density-dependent quark mass model of the well-known density-dependent quark mass model. We ﬁnd that the effect of magnetic ﬁeld, both on the maximum mass and radial frequencies, is rather small. Also a proto strange star, whether magnetized or otherwise, is more likely to evolve into a strange star rather than transform into a black hole.
Color-flavor locked strange quark matter in a mass density-dependent model
Properties of color-flavor locked (CFL) strange quark matter have been studied in a mass-density-dependent model, and compared with the results in the conventional bag model. In both models, the CFL phase is more stable than the normal nuclear matter for reasonable parameters. However, the lower density behavior of the sound velocity in this model is completely opposite to that in the bag model, which makes the maximum mass of CFL quark stars in the mass-density-dependent model larger than that in the bag model. (authors)
Neutrino Masses, Scale-Dependent Growth, and Redshift-Space Distortions
Hernández, Oscar F
2016-01-01
Massive neutrinos leave a unique signature in the large scale clustering of matter. We investigate the wavenumber dependence of the growth factor arising from neutrino masses and use a Fisher analysis to determine the aspects of a galaxy survey needed to measure this scale dependence.
Conformally Flat Metric, Position-Dependent Mass and Cold Dark Matter
Tomilchik, L M; Tomilchik, Lev M.; Kudryashov, Vladimir V.
2004-01-01
The maximal acceleration (MA) problem associated with the position-dependent rest mass concept is considered. New arguments in favor of the mass-dependent maximal acceleration (MDMA) are put forward. The hypothesis that there exists a maximal force with the numerical value equal to the inverse Einstein's gravitation constant is advanced. The Lagrangian and Hamiltonian classical dynamics of a point-like particle with the coordinate-dependent mass is given. The effective Lagrangian for the pure gravitational interaction of a test particle is proposed. Within the scope of this model the typical spiral galaxy rotation is described. It is shown that by this model the peculiar form of the corresponding rotation curve is as a whole reproduced without recourse to the dark matter concept. Also, it is demonstrated that the canonical quantization of this model leads directly to the Dirac oscillator model for a particle with Plank's mass.
Production and Resource Scheduling in Mass Customization with Dependent Setup Consideration
Nielsen, Izabela Ewa; Bocewicz, G.; Do, Ngoc Anh Dung
2014-01-01
contribute to the success of mass customization. This paper addresses the problem of production and resource scheduling for a production system with dependent setup and internal transportation such as AGVs in a mass customization environment. A constraint-programming-based methodology is developed to satisfy......Mass customization has been implemented in services and manufactures to increase the competitiveness of companies. In a manufacturing company, the procedure for production and resource scheduling has to be changed to adapt to mass customization. A good production and resource scheduling will...... the customer demands on-time. An example is presented to illustrate the performance of the proposed methodology....
Does the body mass depend upon its speed. Discussion via exchange of letters
Amusia, Miron Ya
2013-01-01
The presented letters covers an almost year-long discussion of the author and a Very Qualified scientist, VQS, about the dependence of mass upon speed if relativistic corrections are taken into account. VQS believes that since mass is a scalar, it cannot depend upon speed and has to be the same in all inertial coordinate frames. In his view, the very idea of speed dependence of the mass of a particle or a body is incorrect and misleading. As such, the notion of speed dependence of a particle mass has to be eliminated from textbooks on physics and from teaching of this subject. The author claims that this notion has the right to exist, is easily understandable and convenient for most of the students, both non physicists and even physicist. His view is that it is nothing wrong in expressions like particle mass increases with the growth of speed. His view upon the debate is that both approaches are equally correct. His view is that the dilemma depends or not depends is a matter of taste and convenience, not of s...
A new methodology to test galaxy formation models using the dependence of clustering on stellar mass
Campbell, David J R; Mitchell, Peter D; Helly, John C; Gonzalez-Perez, Violeta; Lacey, Cedric G; Lagos, Claudia del P; Simha, Vimal; Farrow, Daniel J
2014-01-01
We present predictions for the two-point correlation function of galaxy clustering as a function of stellar mass, computed using two new versions of the GALFORM semi-analytic galaxy formation model. These models make use of a new high resolution, large volume N-body simulation, set in the WMAP7 cosmology. One model uses a universal stellar initial mass function (IMF), while the other assumes different IMFs for quiescent star formation and bursts. Particular consideration is given to how the assumptions required to estimate the stellar masses of observed galaxies (such as the choice of IMF, stellar population synthesis model and dust extinction) influence the perceived dependence of galaxy clustering on stellar mass. Broad-band spectral energy distribution fitting is carried out to estimate stellar masses for the model galaxies in the same manner as in observational studies. We show clear differences between the clustering signals computed using the true and estimated model stellar masses. As such, we highligh...
Analytical theory for the initial mass function: III time dependence and star formation rate
Hennebelle, Patrick
2013-01-01
The present paper extends our previous theory of the stellar initial mass function (IMF) by including the time-dependence, and by including the impact of magnetic field. The predicted mass spectra are similar to the time independent ones with slightly shallower slopes at large masses and peak locations shifted toward smaller masses by a factor of a few. Assuming that star-forming clumps follow Larson type relations, we obtain core mass functions in good agreement with the observationally derived IMF, in particular when taking into account the thermodynamics of the gas. The time-dependent theory directly yields an analytical expression for the star formation rate (SFR) at cloud scales. The SFR values agree well with the observational determinations of various Galactic molecular clouds. Furthermore, we show that the SFR does not simply depend linearly on density, as sometimes claimed in the literature, but depends also strongly on the clump mass/size, which yields the observed scatter. We stress, however, that ...
EVIDENCE FOR ENVIRONMENTAL DEPENDENCE OF THE UPPER STELLAR INITIAL MASS FUNCTION IN ORION A
We extend our previous study of the stellar population of L1641, the lower-density star-forming region of the Orion A cloud south of the dense Orion Nebula Cluster (ONC), with the goal of testing whether there is a statistically significant deficiency of high-mass stars in low-density regions. Previously, we compared the observed ratio of low-mass stars to high-mass stars with theoretical models of the stellar initial mass function (IMF) to infer a deficiency of the highest-mass stars in L1641. We expand our population study to identify the intermediate-mass (late B to G) L1641 members in an attempt to make a more direct comparison with the mass function of the nearby ONC. The spectral-type distribution and the K-band luminosity function of L1641 are similar to those of the ONC, but problems of incompleteness and contamination prevent us from making a detailed test for differences. We limit our analysis to statistical tests of the ratio of high-mass to low-mass stars, which indicate a probability of only 3% that the ONC and the southern region of L1641 were drawn from the same population, supporting the hypothesis that the upper-mass end of the IMF is dependent on environmental density.
THE MASS-DEPENDENCE OF ANGULAR MOMENTUM EVOLUTION IN SUN-LIKE STARS
Matt, Sean P.; Baraffe, Isabelle; Chabrier, Gilles [Department of Physics and Astronomy, University of Exeter, Physics Building, Stocker Road, Exeter, EX4 4QL (United Kingdom); Brun, A. Sacha [Laboratoire AIM Paris-Saclay, CEA/Irfu Université Paris-Diderot CNRS/INSU, F-91191 Gif-sur-Yvette (France); Bouvier, Jérôme, E-mail: s.matt@exeter.ac.uk [Université de Grenoble Alpes, IPAG, F-38000 Grenoble (France)
2015-02-01
To better understand the observed distributions of the rotation rate and magnetic activity of Sun-like and low-mass stars, we derive a physically motivated scaling for the dependence of the stellar wind torque on the Rossby number. The torque also contains an empirically derived scaling with stellar mass (and radius), which provides new insight into the mass-dependence of stellar magnetic and wind properties. We demonstrate that this new formulation explains why the lowest mass stars are observed to maintain rapid rotation for much longer than solar-mass stars, and simultaneously why older populations exhibit a sequence of slowly rotating stars, in which the low-mass stars rotate more slowly than solar-mass stars. The model also reproduces some previously unexplained features in the period-mass diagram for the Kepler field, notably: the particular shape of the ''upper envelope'' of the distribution, suggesting that ∼95% of Kepler field stars with measured rotation periods are younger than ∼4 Gyr; and the shape of the ''lower envelope'', corresponding to the location where stars transition between magnetically saturated and unsaturated regimes.
Jia, Lian-Bao; Li, Xue-Qian
2016-01-01
The WIMPs are considered one of the most favorable dark matter (DM) candidates, but as the upper bound on the interaction between DM and standard model (SM) particles obtained by the upgraded facilities for direct detection of DM gets lower and lower. Researchers turn their attention to search for less massive DM candidates, i.e. light dark matter of MeV scale. The recently measured anomalous transition in $^8$Be suggests that there exists a vectorial boson which may mediate the interaction b...
Midya, Bikashkali; Roychoudhury, Rajkumar
2010-01-01
Here we have studied first and second-order intertwining approach to generate isospectral partner potentials of position-dependent (effective) mass Schroedinger equation. The second-order intertwiner is constructed directly by taking it as second order linear differential operator with position depndent coefficients and the system of equations arising from the intertwining relationship is solved for the coefficients by taking an ansatz. A complete scheme for obtaining general solution is obtained which is valid for any arbitrary potential and mass function. The proposed technique allows us to generate isospectral potentials with the following spectral modifications: (i) to add new bound state(s), (ii) to remove bound state(s) and (iii) to leave the spectrum unaffected. To explain our findings with the help of an illustration, we have used point canonical transformation (PCT) to obtain the general solution of the position dependent mass Schrodinger equation corresponding to a potential and mass function. It is...
Higgs boson pair production in gluon fusion at NLO with full top-quark mass dependence
Borowka, S; Heinrich, G; Jones, S P; Kerner, M; Schlenk, J; Schubert, U; Zirke, T
2016-01-01
We present the calculation of the cross section and invariant mass distribution for Higgs boson pair production in gluon fusion at next-to-leading order (NLO) in QCD. Top-quark masses are fully taken into account throughout the calculation. The virtual two-loop amplitude has been generated using an extension of the program GoSam supplemented with an interface to Reduze for the integral reduction. The occurring integrals have been calculated numerically using the program SecDec. Our results, including the full top-quark mass dependence for the first time, allow us to assess the validity of various approximations proposed in the literature, which we also recalculate. We find substantial deviations between the NLO result and the different approximations, which emphasizes the importance of including the full top-quark mass dependence at NLO.
Panahi, H; Bakhshi, Z, E-mail: t-panahi@guilan.ac.ir [Department of Physics, University of Guilan, Rasht 51335-1914 (Iran, Islamic Republic of)
2011-04-29
We study the one-dimensional non-Hermitian imaginary potential with a real energy spectrum in the framework of the position-dependent effective mass Dirac equation. The Dirac equation is mapped into the exactly solvable Schroedinger-like equation endowed with position-dependent effective mass that we present a new procedure to solve it. The point canonical transformation in non-relativistic quantum mechanics is applied as an algebraic method to obtain the mass function and then by using the obtained mass function, the imaginary potential can be obtained. The spinor wavefunctions for some of the obtained electrostatic potentials are given in terms of orthogonal polynomials. We also obtain the relativistic bound state spectrum for each case in terms of the bound state spectrum of the solvable potentials.
We study the one-dimensional non-Hermitian imaginary potential with a real energy spectrum in the framework of the position-dependent effective mass Dirac equation. The Dirac equation is mapped into the exactly solvable Schroedinger-like equation endowed with position-dependent effective mass that we present a new procedure to solve it. The point canonical transformation in non-relativistic quantum mechanics is applied as an algebraic method to obtain the mass function and then by using the obtained mass function, the imaginary potential can be obtained. The spinor wavefunctions for some of the obtained electrostatic potentials are given in terms of orthogonal polynomials. We also obtain the relativistic bound state spectrum for each case in terms of the bound state spectrum of the solvable potentials.
Spin dependence of the quasiparticle masses in CeRu2Si2
We have measured the spin dependence of the quasiparticle masses on the two small ellipsoidal Fermi surface sheets of CeRu2Si2 via the dHvA effect. The field variation of the effective masses above the metamagnetic transition was obtained for the β' and γ' oscillations. We find that ma*(β')∼5m↑*(β'), ma*(γ')∼3m↑*(γ')
Mass dependence of shear viscosity in a binary fluid mixture: mode-coupling theory.
Ali, Sk Musharaf; Samanta, Alok; Choudhury, Niharendu; Ghosh, Swapan K
2006-11-01
An expression for the shear viscosity of a binary fluid mixture is derived using mode-coupling theory in order to study the mass dependence. The calculated results on shear viscosity for a binary isotopic Lennard-Jones fluid mixture show good agreement with results from molecular dynamics simulation carried out over a wide range of mass ratio at different composition. Also proposed is a new generalized Stokes-Einstein relation connecting the individual diffusivities to shear viscosity. PMID:17279895
Vitamin B12–dependent taurine synthesis regulates growth and bone mass
Roman-Garcia, Pablo; Quiros-Gonzalez, Isabel; Mottram, Lynda; Lieben, Liesbet; Sharan, Kunal; Wangwiwatsin, Arporn; Tubio, Jose; Lewis, Kirsty; Wilkinson, Debbie; Santhanam, Balaji; Sarper, Nazan; Clare, Simon; Vassiliou, George S; Velagapudi, Vidya R.; Dougan, Gordon
2014-01-01
Both maternal and offspring-derived factors contribute to lifelong growth and bone mass accrual, although the specific role of maternal deficiencies in the growth and bone mass of offspring is poorly understood. In the present study, we have shown that vitamin B12 (B12) deficiency in a murine genetic model results in severe postweaning growth retardation and osteoporosis, and the severity and time of onset of this phenotype in the offspring depends on the maternal genotype. Using integrated p...
The environmental dependence of the stellar mass-size relation in STAGES galaxies
Maltby, David T; Gray, Meghan E; Barden, Marco; Haeussler, Boris; Wolf, Christian; Peng, Chien Y; Jahnke, Knud; McIntosh, Daniel H; Boehm, Asmus; van Kampen, Eelco
2009-01-01
We present the stellar mass-size relations for elliptical, lenticular, and spiral galaxies in the field and cluster environments using HST/ACS imaging and data from the Space Telescope A901/2 Galaxy Evolution Survey (STAGES). We use a large sample of ~1200 field and cluster galaxies, and a sub-sample of cluster core galaxies, and quantify the significance of any putative environmental dependence on the stellar mass-size relation. For elliptical, lenticular, and high-mass (log M*/M_sun > 10) spiral galaxies we find no evidence to suggest any such environmental dependence, implying that internal drivers are governing their size evolution. For intermediate/low-mass spirals (log M*/M_sun < 10) we find evidence, significant at the 2-sigma level, for a possible environmental dependence on galaxy sizes: the mean effective radius a_e for lower-mass spirals is ~15-20 per cent larger in the field than in the cluster. This is due to a population of low-mass large-a_e field spirals that are largely absent from the clu...
Diffusion in time-dependent random environments: mass fluctuations and scaling properties
A mass-ejection model in a time-dependent random environment with both temporal and spatial correlations is introduced. When the environment has a finite correlation length, individual particle trajectories are found to diffuse at large times with a displacement distribution that approaches a Gaussian. The collective dynamics of diffusing particles reaches a statistically stationary state, which is characterized in terms of a fluctuating mass density field. The probability distribution of density is studied numerically for both smooth and non-smooth scale-invariant random environments. Competition between trapping in the regions where the ejection rate of the environment vanishes and mixing due to its temporal dependence leads to large fluctuations of mass. These mechanisms are found to result in the presence of intermediate power-law tails in the probability distribution of the mass density. For spatially differentiable environments, the exponent of the right tail is shown to be universal and equal to -3/2. However, at small values, it is found to depend on the environment. Finally, spatial scaling properties of the mass distribution are investigated. The distribution of the coarse-grained density is shown to possess some rescaling properties that depend on the scale, the amplitude of the ejection rate and the Hölder exponent of the environment. (paper)
Anomalous extracellular diffusion in rat cerebellum.
Xiao, Fanrong; Hrabe, Jan; Hrabetova, Sabina
2015-05-01
Extracellular space (ECS) is a major channel transporting biologically active molecules and drugs in the brain. Diffusion-mediated transport of these substances is hindered by the ECS structure but the microscopic basis of this hindrance is not fully understood. One hypothesis proposes that the hindrance originates in large part from the presence of dead-space (DS) microdomains that can transiently retain diffusing molecules. Because previous theoretical and modeling work reported an initial period of anomalous diffusion in similar environments, we expected that brain regions densely populated by DS microdomains would exhibit anomalous extracellular diffusion. Specifically, we targeted granular layers (GL) of rat and turtle cerebella that are populated with large and geometrically complex glomeruli. The integrative optical imaging (IOI) method was employed to evaluate diffusion of fluorophore-labeled dextran (MW 3000) in GL, and the IOI data analysis was adapted to quantify the anomalous diffusion exponent dw from the IOI records. Diffusion was significantly anomalous in rat GL, where dw reached 4.8. In the geometrically simpler turtle GL, dw was elevated but not robustly anomalous (dw = 2.6). The experimental work was complemented by numerical Monte Carlo simulations of anomalous ECS diffusion in several three-dimensional tissue models containing glomeruli-like structures. It demonstrated that both the duration of transiently anomalous diffusion and the anomalous exponent depend on the size of model glomeruli and the degree of their wrapping. In conclusion, we have found anomalous extracellular diffusion in the GL of rat cerebellum. This finding lends support to the DS microdomain hypothesis. Transiently anomalous diffusion also has a profound effect on the spatiotemporal distribution of molecules released into the ECS, especially at diffusion distances on the order of a few cell diameters, speeding up short-range diffusion-mediated signals in less permeable
The orientation dependence of quasar single-epoch black hole mass scaling relationships
Runnoe, Jessie C.; Brotherton, Michael; Shang, Zhaohui; Wills, Beverley; DiPompeo, Michael
2012-01-01
Black hole masses are estimated for radio-loud quasars using several self-consistent scaling relationships based on emission-line widths and continuum luminosities. The emission lines used, H-beta, Mg II, and C IV, have different dependencies on orientation as estimated by radio core dominance. We compare differences in the log of black hole masses estimated from different emission lines and show that they depend on radio core dominance in the sense that core-dominated, jet-on objects have sy...
Ishii, Masahiro; Yahiro, Masanobu
2016-01-01
We propose a practical effective model by introducing temperature ($T$) dependence to the coupling strengths of four-quark and six-quark Kobayashi-Maskawa-'t Hooft interactions in the 2+1 flavor Polyakov-loop extended Nambu-Jona-Lasinio model. The $T$ dependence is determined from LQCD data on the renormalized chiral condensate around the pseudocritical temperature $T_c^{\\chi}$ of chiral crossover and the screening-mass difference between $\\pi$ and $a_0$ mesons in $T > 1.1T_c^\\chi$ where only the $U(1)_{\\rm A}$-symmetry breaking survives. The model well reproduces LQCD data on screening masses $M_{\\xi}^{\\rm scr}(T)$ for both scalar and pseudoscalar mesons, particularly in $T \\ge T_c^{\\chi}$. Using this effective model, we predict meson pole masses $M_{\\xi}^{\\rm pole}(T)$ for scalar and pseudoscalar mesons. For $\\eta'$ meson, the prediction is consistent with the experimental value at finite $T$ measured in heavy-ion collisions. We point out that the relation $M_{\\xi}^{\\rm scr}(T)-M_{\\xi}^{\\rm pole}(T) \\approx...
The Debye screening masses of the σ, ω and neutral ρ mesons and the photon are calculated in the relativistic mean-field approximation. As the density of the nucleon increases, all the screening masses of mesons increase. A different result with Brown–Rho scaling is shown, which implies a reduction in the mass of all the mesons in the nuclear matter, except the pion. Replacing the masses of the mesons with their corresponding screening masses in the Walecka-1 model, five saturation properties of the nuclear matter are fixed reasonably, and then a density-dependent relativistic mean-field model is proposed without introducing the nonlinear self-coupling terms of mesons. (author)
Remarks on the solution of the position-dependent mass Schroedinger equation
An approximate method is proposed to solve the position-dependent mass (PDM) Schroedinger equation. The procedure suggested here leads to the solution of the PDM Schroedinger equation without transforming the potential function to the mass space or vice versa. The method based on the asymptotic Taylor expansion of the function produces an approximate analytical expression for eigenfunction and numerical results for eigenvalues of the PDM Schroedinger equation. The results show that the PDM and constant mass Schroedinger equations are not isospectral. The calculations are carried out with the aid of a computer system of symbolic or numerical calculation by constructing a simple algorithm.
Asymptotic Behavior of a Viscous Liquid-Gas Model with Mass-Dependent Viscosity and Vacuum
liu, Qingqing
2011-01-01
In this paper, we consider two classes of free boundary value problems of a viscous two-phase liquid-gas model relevant to the flow in wells and pipelines with mass-dependent viscosity coefficient. The liquid is treated as an incompressible fluid whereas the gas is assumed to be polytropic. We obtain the asymptotic behavior and decay rates of the mass functions $n(x,t)$,\\$m(x,t)$ when the initial masses are assumed to be connected to vacuum both discontinuously and continuously, which improves the corresponding result about Navier-Stokes equations in \\cite{Zhu}.
Asymptotic behavior of a viscous liquid-gas model with mass-dependent viscosity and vacuum
Liu, Qingqing; Zhu, Changjiang
In this paper, we consider two classes of free boundary value problems of a viscous two-phase liquid-gas model relevant to the flow in wells and pipelines with mass-dependent viscosity coefficient. The liquid is treated as an incompressible fluid whereas the gas is assumed to be polytropic. We obtain the asymptotic behavior and decay rates of the mass functions n(x,t), m(x,t) when the initial masses are assumed to be connected to vacuum both discontinuously and continuously, which improves the corresponding result about Navier-Stokes equations in Zhu (2010) [23].
Asymptotic Behavior of a Viscous Liquid-Gas Model with Mass-Dependent Viscosity and Vacuum
Liu, Qingqing; Zhu, Changjiang
2011-01-01
In this paper, we consider two classes of free boundary value problems of a viscous two-phase liquid-gas model relevant to the flow in wells and pipelines with mass-dependent viscosity coefficient. The liquid is treated as an incompressible fluid whereas the gas is assumed to be polytropic. We obtain the asymptotic behavior and decay rates of the mass functions $n(x,t)$,\\$m(x,t)$ when the initial masses are assumed to be connected to vacuum both discontinuously and continuously, which improve...
Meier, Matthias M M; Marty, Bernard
2016-01-01
We have measured the concentration, isotopic composition and thermal release profiles of Mercury (Hg) in a suite of meteorites, including both chondrites and achondrites. We find large variations in Hg concentration between different meteorites (ca. 10 ppb to 14'000 ppb), with the highest concentration orders of magnitude above the expected bulk solar system silicates value. From the presence of several different Hg carrier phases in thermal release profiles (150 to 650 {\\deg}C), we argue that these variations are unlikely to be mainly due to terrestrial contamination. The Hg abundance of meteorites shows no correlation with petrographic type, or mass-dependent fractionation of Hg isotopes. Most carbonaceous chondrites show mass-independent enrichments in the odd-numbered isotopes 199Hg and 201Hg. We show that the enrichments are not nucleosynthetic, as we do not find corresponding nucleosynthetic deficits of 196Hg. Instead, they can partially be explained by Hg evaporation and redeposition during heating of ...
Velter-Stefanescu, M.; Duliu, O. G.
2007-04-01
A ceramic high temperature superconductor [HTS] of Y-Ba-Cu-O type has been investigated at 77 K by using a standard X-band Electron Paramagnetic Resonance (EPR) configuration. At very low microwave power (DPPH signal, pleading for an unambiguous absorption process, but it commutes to a typical superconductor signal (i.e. opposite to DPPH signal phase) with increasing the microwave power. At the same time, Cu2+ signal appreciably changes its shape with increasing microwave power. These anomalous behaviors could be in part explained by a conventional SQUID response at microwave frequency by taking into account that the sample itself could be described by a collection of both Josephson and proximity junctions.
The ATLAS and CMS Collaborations
2016-01-01
A procedure is presented to combine data from the ATLAS and CMS experiments on $ZZ$ production to obtain constraints on anomalous neutral triple gauge boson couplings. Statistical and systematic uncertainties and their correlations are taken into account. Data from $pp$ collisions at a center-of-mass energy of 7 TeV delivered by the LHC are used. The datasets correspond to integrated luminosities of 4.6 and 5.0 $\\rm{fb^{−1}}$ for ATLAS and CMS, respectively. The combination is performed in the fully leptonic decay channels ZZ → 2l2ν (ATLAS) and ZZ → 4l (ATLAS, CMS). Combined limits on the coupling parameters are −0.010 < f4γ < 0.011, −0.0087 < f4Z < 0.0091, −0.011 < f5γ < 0.010, and −0.0091 < f5Z < 0.0089 at 95% C.L., where all other parameters are fixed to the standard model values. These results represent the first combined limits of the ATLAS and CMS collaborations for anomalous gauge boson couplings.
Singhal, R K; Dalela, S; Sekhar, B; Jain, D C; Garg, K B
2003-01-01
Some experiments have recently shown that in the YBCO detwinned system charge aggregation takes place in the Cu-O sub 2 plane along the b-axis at T>>T sub c followed by formation of Cooper pairs, again in the normal state. Polarised X-ray absorption measurements at the O K and Cu L sub 3 absorption edges in E parallel b orientation have been carried out on underdoped and overdoped single crystals of La sub 2 sub - sub x Sr sub x CuO sub 4 through a temperature range of 10-300 K to study the dependence of the itinerant hole density. Both the crystals do show an anomalous temperature dependence but there is a wide divergence in the earlier and our results. This paper discusses the results and possible causes for the difference.
NEW CONSTRAINTS ON MASS-DEPENDENT DISRUPTION OF STAR CLUSTERS IN M51
We use UBVI Hα images of the Whirlpool galaxy, M51, taken with the Advanced Camera for Surveys and WFPC2 cameras on the Hubble Space Telescope (HST) to select star clusters, and to estimate their masses and ages by comparing their observed colors with predictions from population synthesis models. We construct the mass function of intermediate-age (1-4 x 108 yr) clusters, and find that it is well described by a power law, ψ(M) ∝ Mβ, with β = -2.1 ± 0.2, for clusters more massive than M ∼ 6 x 103 Msun. This extends the mass function of intermediate-age clusters in M51 to masses lower by nearly a factor of five over previous determinations. The mass function does not show evidence for curvature at either the high or low mass end. This shape indicates that there is no evidence for the earlier disruption of lower mass clusters compared with their higher mass counterparts (i.e., no mass-dependent disruption) over the observed range of masses and ages, or for a physical upper mass limit MC with which clusters in M51 can form. These conclusions differ from previous suggestions based on poorer-quality HST observations. We discuss their implications for the formation and disruption of the clusters. Ages of clusters in two 'feathers', stellar features extending from the outer portion of a spiral arm, show that the feather with a larger pitch angle formed earlier, and over a longer period, than the other.
Quantum particles trapped in a position-dependent mass barrier; a d-dimensional recipe
We consider a free particle, V(r)=0, with a position-dependent mass m(r)=1/(1+σ2r2)2 in the d-dimensional Schrodinger equation. The effective potential turns out to be a generalized Poschl-Teller potential that admits exact solution
Flatland Position-Dependent-Mass: Polar Coordinates, Separability and Exact Solvability
Omar Mustafa
2010-10-01
Full Text Available The kinetic energy operator with position-dependent-mass in plane polar coordinates is obtained. The separability of the corresponding Schrödinger equation is discussed. A hypothetical toy model is reported and two exactly solvable examples are studied.
Properties of Quasi-Oscillator in Position-Dependent Mass Formalism
Zare, Soroush
2016-01-01
After introducing Schr\\"odinger equation within position- dependent mass formalism, a quasi-oscillator has been considered. Eigen functions and energy spectra have been obtained analytical. Then thermodynamic properties, information entropy and uncertainty in coordinate and momentum corresponding the considered system have calculated as well as some depicted.
Environmental dependence of the H I mass function in the ALFALFA 70% catalogue
Jones, Michael G.; Papastergis, Emmanouil; Haynes, Martha P.; Giovanelli, Riccardo
2016-04-01
We search for environmental dependence of the H I mass function in the Arecibo Legacy Fast ALFA survey (ALFALFA) 70 per cent catalogue. The catalogue is split into quartiles of environment density based on the projected neighbour density of neighbours found in both Sloan Digital Sky Survey (SDSS) and 2MASS Redshift Survey (2MRS) volume-limited reference catalogues. We find the Schechter function `knee' mass to be dependent on environment, with the value of log (M*/M⊙) shifting from 9.81 ± 0.02 to 10.00 ± 0.03 between the lowest and highest density quartiles. However, this dependence was only observed when defining environment based on the SDSS reference catalogue, not 2MRS. We interpret these results as meaning that the local environment is the dominant cause of the shift in M*, and that the larger scales that 2MRS probes (compared to SDSS) are almost irrelevant. In addition, we also use a fixed aperture method to probe environment, and find tentative evidence that H I-deficiency depresses the value of M* in the highest density regions. We find no significant dependence of the low-mass slope on environment in any test, using either method. Tensions between these results and those from the literature, are discussed and alternative explanations are explored.
鞠国兴
2011-01-01
Using the coordinate transformation method, we study the polynomial solutions of the Schr6dinger equation with position-dependent mass （PDM）. The explicit expressions for the potentials, energy eigenvalues, and eigenfunctions of the systems are given. The issues related to normalization of the wavefunetions and Hermiticity of the Hamiltonian are also analyzed.
New scenarios for classical and quantum mechanical systems with position dependent mass
Morris, J R
2015-01-01
An inhomogeneous Kaluza-Klein compactification to four dimensions, followed by a conformal transformation, results in a system with position dependent mass (PDM). This origin of a PDM is quite different from the condensed matter one. A substantial generalization of a previously studied nonlinear oscillator with variable mass is obtained, wherein the position dependence of the mass of a nonrelativistic particle is due to a dilatonic coupling function emerging from the extra dimension. Previously obtained solutions for such systems can be extended and reinterpreted as nonrelativistic particles interacting with dilaton fields, which, themselves, can have interesting structures. An application is presented for the nonlinear oscillator, where within the new scenario the particle is coupled to a dilatonic string.
Parity nonconservation in nuclear fission: does it depend on fragment mass/energy?
For fission of 233U induced by polarized cold neutrons the dependence of the PNC asymmetry coefficient αnf(mLF, TKE) on light fragment mass mLF and total kinetic energy TKE was studied. Concurrently the angular distribution predicted for PNC reactions was tested. Altogether more than 2x1010 fission events with high mass/energy resolution have been collected. This corresponds to an increase in the statistics compared to previous experiments (U. Graf, F. Goennenwein, P. Geltenbort, et al., Z. Phys. A 351 (1995) 281 and V.A. Vesna, V.A. Knyaz'kov, E.A. Kolomenskii et al., JETP. Lett. 31 (1980) 663) by a factor of about 20. The preliminary analysis of the PNC asymmetry shows no significant variation of αnf for different fragment masses/energies, whereas the prediction concerning the angular dependence was confirmed with a precision not obtained up to now
The mass dependence of the signal peak height of a Bragg-curve ionization chamber
The Bragg-curve detector of the parallel plate ionization chamber type generates a signal that is a distorted replica of the original Bragg-curve. In result of this distortion, the signal peak height is not only a function of the atomic number of the heavy ion, as it is often stated, but also of the particle mass. This mass effect was studied with the aid of computer simulation, and it was found to be dependent on the Frisch grid to anode gap width and on the detector gas. The charge resolution of the detector is affected very significantly by this mass dependence of the signal peak height. Therefore, a careful selection of the detector gas and the grid to anode gap width is necessary, if good charge resolution over a wide range of heavy ions is required. (orig.)
The mass dependence of the signal peak height of a Bragg-curve ionization chamber
Shenhav, N. J.; Stelzer, H.
1985-01-01
The Bragg-curve detector of the parallel plate ionization chamber type generates a signal that is a distorted replica of the original Bragg-curve. In result of this distortion, the signal peak height is not only a function of the atomic number of the heavy ion, as it is often stated, but also of the particle mass. This mass effect was studied with the aid of computer simulation, and it was found to be dependent on the Frisch grid to anode gap width and on the detector gas. The charge resolution of the detector is affected very significantly by this mass dependence of the signal peak height. Therefore, a careful selection of the detector gas and the grid to anode gap width is necessary, if good charge resolution over a wide range of heavy ions is required.
The mass spectra of vapor-phase n-hexane, cyclohexane, and diethyl ether are measured as a function of temperature by photoionization mass spectrometry. Three fixed wavelengths are used, the Kr I, Ar I, and Ne I resonance lines. The results are interpreted on the basis of a simplified version of the quasi-equilibrium theory. In this model it is assumed that the density of states of a transition state can be described by the density of states of the neutral molecule multiplied by a phase space scaling factor. The phase space scaling factors are fitted for an optimum reconstruction of the photon and temperature-dependent mass spectra. The knowledge obtained about the fragmentation reaction rates of n-hexane is applied to field ionization mass spectra, which results in an estimate of the average energy deposition in the molecular ion of 0.77 ± 0.1 eV
Orbital Evolution of Mass-transferring Eccentric Binary Systems. I. Phase-dependent Evolution
Dosopoulou, Fani; Kalogera, Vicky
2016-07-01
Observations reveal that mass-transferring binary systems may have non-zero orbital eccentricities. The time evolution of the orbital semimajor axis and eccentricity of mass-transferring eccentric binary systems is an important part of binary evolution theory and has been widely studied. However, various different approaches to and assumptions on the subject have made the literature difficult to comprehend and comparisons between different orbital element time evolution equations not easy to make. Consequently, no self-consistent treatment of this phase has ever been included in binary population synthesis codes. In this paper, we present a general formalism to derive the time evolution equations of the binary orbital elements, treating mass loss and mass transfer as perturbations of the general two-body problem. We present the self-consistent form of the perturbing acceleration and phase-dependent time evolution equations for the orbital elements under different mass loss/transfer processes. First, we study the cases of isotropic and anisotropic wind mass loss. Then, we proceed with non-isotropic ejection and accretion in a conservative as well as a non-conservative manner for both point masses and extended bodies. We compare the derived equations with similar work in the literature and explain the existing discrepancies.
Evidence for non-analytic light quark mass dependence in the baryon spectrum
Walker-Loud, Andre
2011-01-01
Using precise lattice QCD computations of the baryon spectrum, we present the first direct evidence for the presence of contributions to the baryon masses which are non-analytic in the light quark masses; contributions which are often denoted "chiral logarithms". We isolate the poor convergence of SU(3) baryon chiral perturbation theory to the flavor-singlet mass combination. The flavor-octet baryon mass splittings, which are corrected by chiral logarithms at next to leading order in SU(3) chiral perturbation theory, yield baryon-pion axial coupling constants D, F, C and H consistent with QCD values; the first evidence of chiral logarithms in the baryon spectrum. The Gell-Mann--Okubo relation, a flavor-27 baryon mass splitting, which is dominated by chiral corrections from light quark masses, provides further evidence for the presence of non-analytic light quark mass dependence in the baryon spectrum; we simultaneously find the GMO relation to be inconsistent with the first few terms in a taylor expansion in ...
The charmonium dissociation in an "anomalous wind"
Sadofyev, Andrey V
2016-01-01
We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries ``anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the ``anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the ``anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and {\\it qualitative} difference between anomalous effects on the charmonium color screening length which are {\\it model-dependent} and those on the heavy quark drag force which are fixed by the second law of thermodynamics. We speculate on the possible charmonium dissociation induced by chiral anomaly in heavy ion collisions.
The charmonium dissociation in an "anomalous wind"
Sadofyev, Andrey V.; Yin, Yi
2016-01-01
We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries "anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the "anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the "anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and qualitative difference between anomalous effects on the charmonium color screening length which are model-dependent and those on the heavy quark drag force which are fixed by the second law of thermodynamics. We speculate on the possible charmonium dissociation induced by the chiral anomaly in heavy ion collisions.
Ortenzi, L.; Gretarsson, H.; Kasahara, S.; Matsuda, Y.; Shibauchi, T.; Finkelstein, K. D.; Wu, W.; Julian, S. R.; Kim, Young-June; Mazin, I. I.; Boeri, L.
2015-01-01
We report a combination of Fe K β x-ray emission spectroscopy and density functional reduced Stoner theory calculations to investigate the correlation between structural and magnetic degrees of freedom in CaFe2(As1-xPx) 2 . The puzzling temperature behavior of the local moment found in rare earth-doped CaFe2As2 [H. Gretarsson et al., Phys. Rev. Lett. 110, 047003 (2013)] is also observed in CaFe2(As1-xPx) 2 . We explain this phenomenon based on first-principles calculations with scaled magnetic interaction. One scaling parameter is sufficient to describe quantitatively the magnetic moments in both CaFe2(As1-xPx) 2 (x =0.055 ) and Ca0.78La0.22Fe2As2 at all temperatures. The anomalous growth of the local moments with increasing temperature can be understood from the observed large thermal expansion of the c -axis lattice parameter combined with strong magnetoelastic coupling. These effects originate from the strong tendency to form As-As dimers across the Ca layer in the CaFe2As2 family of materials. Our results emphasize the dual local-itinerant character of magnetism in Fe pnictides.
2002-01-01
The proposal concerns an extension to higher energies of previous experiments which have provided evidence for anomalously short reaction mean free paths among projectile fragments from heavy ion interactions.\\\\ \\\\ It is intended to provide information on the interaction properties of projectile fragments, mainly 3He, P, D, T as well as of scattered 4He nuclei in passive detectors exposed to beams of energies exceeding those available in previous experim factor of about 7. \\\\ \\\\ Interaction mean free paths and event topologies will be measured in a nuclear emulsion stack (LBL) of 7.5~cm~x~5~cm~x~25~cm dimensions. Decay effects will be recorded by comparing the activity of spallation residues in dense and diluted copper target assemblies (Marburg). Target fragmentation will be studied in a stack of silverchloride crystal foils (Frankfurt) of about 7~cm~x~6~cm~x~1~cm dimensions. The \\alpha beam ejected at EJ~62 will be used to provide both exposures at high intensity of 10|1|2 alphas on th and at low intensity ...
Temperature dependence of the cyclotron mass in ZnCdSe/ZnSe multi-QWs
The temperature dependence of the cyclotron resonance mass (CRM) of the magnetopolaron in ZnCdSe/ZnSe multi-quantum wells with strong magnetic field is investigated theoretically using the Lee-Low-Pines variational method. Contributions to the CRM, due to the nonparabolicity of the conduction band and the coupling of electron with both confined longitudinal optical and interface optical phonons, are considered. Results of our calculations are compared with the experimental data, and a qualitative agreement is found over a large temperature range. We show that these three contributions complement each other to determine the cyclotron mass as a function of the temperature. (author)
Mass dispersions in a time-dependent mean-field approach
Characteristic functions for single-particle (s.p.) observables are evaluated by means of a time-dependent variational principle, which involves a state and an observable as conjugate variables. This provides a mean-field expression for fluctuations of s.p. observables, such as mass dispersions. The result differs from TDHF, it requires only the use of existing codes, and it presents attractive theoretical features. First numerical tests are encouraging. In particular, a calculation for 16O + 16O provides a significant increase of the predicted mass dispersion
Bulk viscosity of strange quark matter in density dependent quark mass model
J D Anand; N Chandrika Devi; V K Gupta; S Singh
2000-05-01
We have studied the bulk viscosity of strange quark matter in the density dependent quark mass model (DDQM) and compared results with calculations done earlier in the MIT bag model where , masses were neglected and ﬁrst order interactions were taken into account. We ﬁnd that at low temperatures and high relative perturbations, the bulk viscosity is higher by 2 to 3 orders of magnitude while at low perturbations the enhancement is by 1–2 order of magnitude as compared to earlier results. Also the damping time is 2–3 orders of magnitude lower implying that the star reaches stability much earlier than in MIT bag model calculations.
Time dependent quantum harmonic oscillator subject to a sudden change of mass: continuous solution
Moya C, H. [INAOE, Coordinacion de Optica, AP 51 y 216, 72000 Puebla (Mexico); Fernandez G, M. [Depto. de Fisica, CBI, Universidad Autonoma Metropolitana - Iztapalapa, 09340, Mexico, D.F. AP 55-534 (Mexico)
2007-07-01
We show that a harmonic oscillator subject to a sudden change of mass produces squeezed states. Our study is based on an approximate analytic solution to the time-dependent harmonic oscillator equation with a sub period function parameter. This continuous treatment differs from former studies that involve the matching of two time-independent solutions at the discontinuity. This formalism requires an ad hoc transformation of the original differential equation and is also applicable for rapid, although not necessarily instantaneous, mass variations. (Author)
Improved angular momentum evolution model for solar-like stars II. Exploring the mass dependence
Gallet, Florian
2015-01-01
We developed angular momentum evolution models for 0.5 and 0.8 $M_{\\odot}$ stars. The parametric models include a new wind braking law based on recent numerical simulations of magnetised stellar winds, specific dynamo and mass-loss rate prescriptions, as well as core/envelope decoupling. We compare model predictions to the distributions of rotational periods measured for low mass stars belonging to star forming regions and young open clusters. Furthermore, we explore the mass dependence of model parameters by comparing these new models to the solar-mass models we developed earlier. Rotational evolution models are computed for slow, median, and fast rotators at each stellar mass. The models reproduce reasonably well the rotational behaviour of low-mass stars between 1~Myr and 8-10~Gyr, including pre-main sequence to zero-age main sequence spin up, prompt zero-age main sequence spin down, and early-main sequence convergence of the surface rotation rates. Fast rotators are found to have systematically shorter di...
Halo mass dependence of H I and O VI absorption: evidence for differential kinematics
We studied a sample of 14 galaxies (0.1 < z < 0.7) using HST/WFPC2 imaging and high-resolution HST/COS or HST/STIS quasar spectroscopy of Lyα, Lyβ, and O VI λλ1031, 1037 absorption. The galaxies, having 10.8 ≤ log (M h/M ☉) ≤ 12.2, lie within D = 300 kpc of quasar sightlines, probing out to D/R vir = 3. When the full range of M h and D/R vir of the sample are examined, ∼40% of the H I absorbing clouds can be inferred to be escaping their host halo. The fraction of bound clouds decreases as D/R vir increases such that the escaping fraction is ∼15% for D/R vir < 1, ∼45% for 1 ≤ D/R vir < 2, and ∼90% for 2 ≤ D/R vir < 3. Adopting the median mass log M h/M ☉ = 11.5 to divide the sample into 'higher' and 'lower' mass galaxies, we find a mass dependency for the hot circumgalactic medium kinematics. To our survey limits, O VI absorption is found in only ∼40% of the H I clouds in and around lower mass halos as compared to ∼85% around higher mass halos. For D/R vir < 1, lower mass halos have an escape fraction of ∼65%, whereas higher mass halos have an escape fraction of ∼5%. For 1 ≤ D/R vir < 2, the escape fractions are ∼55% and ∼35% for lower mass and higher mass halos, respectively. For 2 ≤ D/R vir < 3, the escape fraction for lower mass halos is ∼90%. We show that it is highly likely that the absorbing clouds reside within 4R vir of their host galaxies and that the kinematics are dominated by outflows. Our finding of 'differential kinematics' is consistent with the scenario of 'differential wind recycling' proposed by Oppenheimer et al. We discuss the implications for galaxy evolution, the stellar to halo mass function, and the mass-metallicity relationship of galaxies.
The outcome of supernovae in massive binaries; removed mass, and its separation dependence
Hirai, Ryosuke; Sawai, Hidetomo; Yamada, Shoichi [Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo 169-8555 (Japan)
2014-09-01
The majority of massive stars are formed in binary systems. It is hence reasonable to expect that most core-collapse supernovae (CCSNe) take place in binaries and the existence of a companion star may leave some imprints in observed features. Having this in mind, we have conducted two-dimensional hydrodynamical simulations of the collisions of CCSNe ejecta with the companion star in an almost-equal-mass (∼10 M {sub ☉}) binary to find out possible consequences of such events. In particular we pay attention to the amount of mass removed and its dependence on the binary separation. In contrast to the previous surmise, we find that the companion mass is stripped not by momentum transfer but by shock heating. Up to 25% of the original mass can be removed for the closest separations and the removed mass decreases as M {sub ub}∝a {sup –4.3} with the binary separation a. By performing some experimental computations with artificially modified densities of incident ejecta, we show that if the velocity of ejecta is fixed, the density of incident ejecta is the single important parameter that actually determines the removed mass as M{sub ub}∝ρ{sub ej}{sup 1.4}. On the other hand, another set of simulations with modified velocities of incident ejecta demonstrate that the strength of the forward shock, which heats up the stellar material and causes the mass loss of the companion star, is actually the key parameter for the removed mass.
M.Eshghi; M.Hamzavi; S.M.Ikhdair
2013-01-01
The spatially-dependent mass Dirac equation is solved exactly for attractive scalar and repulsive vector Coulomb potentials,including a tensor interaction under the spin and pseudospin symmetric limits.Closed forms of the energy eigenvalue equation and wave functions are obtained for arbitrary spin-orbit quantum number κ.Some numerical results are also given,and the effect of tensor interaction on the bound states is presented.It is shown that tensor interaction removes the degeneracy between two states in the spin doublets.We also investigate the effects of the spatially-dependent mass on the bound states under spin symmetric limit conditions in the absence of tensor interaction.
Various aspects of the Deformation Dependent Mass model of nuclear structure
Petrellis, D; Minkov, N
2015-01-01
Recently, a variant of the Bohr Hamiltonian was proposed where the mass term is allowed to depend on the beta variable of nuclear deformation. Analytic solutions of this modified Hamiltonian have been obtained using the Davidson and the Kratzer potentials, by employing techniques from supersymmetric quantum mechanics. Apart from the new set of analytic solutions, the newly introduced Deformation-Dependent Mass (DDM) model offered a remedy to the problematic behaviour of the moment of inertia in the Bohr Hamiltonian, where it appears to increase proportionally to the square of beta. In the DDM model the moments of inertia increase at a much lower rate, in agreement with experimental data. The current work presents an application of the DDM-model suitable for the description of nuclei at the point of shape/phase transitions between vibrational and gamma-unstable or prolate deformed nuclei and is based on a method that was successfully applied before in the context of critical point symmetries.
Quadratic algebras and position-dependent mass Schr\\"odinger equations
Quesne, C
2007-01-01
During recent years, exact solutions of position-dependent mass Schr\\"odinger equations have inspired intense research activities, based on the use of point canonical transformations, Lie algebraic methods or supersymmetric quantum mechanical techniques. Here we highlight the interest of another approach to such problems, relying on quadratic algebras. We illustrate this point by constructing spectrum generating algebras for a class of $d$-dimensional radial harmonic oscillators with $d\\ge2$ (including the one-dimensional oscillator on the line via some minor changes) and a specific mass choice. This provides us with a counterpart of the well-known su(1,1) Lie algebraic approach to the constant-mass oscillators.
Anomalous Hall effect in YIG$|$Pt bilayers
Meyer, Sibylle; Schlitz, Richard; Geprägs, Stephan; Opel, Matthias; Huebl, Hans; Gross, Rudolf; Goennenwein, Sebastian T. B.
2015-01-01
We measure the ordinary and the anomalous Hall effect in a set of yttrium iron garnet$|$platinum (YIG$|$Pt) bilayers via magnetization orientation dependent magnetoresistance experiments. Our data show that the presence of the ferrimagnetic insulator YIG leads to an anomalous Hall like signature in Pt, sensitive to both Pt thickness and temperature. Interpretation of the experimental findings in terms of the spin Hall anomalous Hall effect indicates that the imaginary part of the spin mixing ...
Classical oscillator with position-dependent mass in a complex domain
Ghosh, Subir; Modak, Sujoy Kumar
2008-01-01
We study complexified Harmonic Oscillator with a position-dependent mass, termed as Complex Exotic Oscillator (CEO). The complexification induces a gauge invariance [19,11]. The role of PT -symmetry is discussed from the perspective of classical trajectories of CEO for real energy. Some trajectories of CEO are similar to those for the particle in a quartic potential in the complex domain [10, 32].
Improved Quark Mass Density-Dependent Model with Non-Linear Scalar Interaction
WU Chen; QIAN Wei-Liang; SU Ru-Keng
2005-01-01
@@ We present an improved quark mass density-dependent model which includes the quark and non-linear scalar field coupling. The wavefunction of quark is given. The rms charge radius, the magnetic moment, and the ratio between the axial-vector and the vectorβ-decay coupling constants of the nucleon are calculated. We find that the results given the present model are in agreement with experiments.
The environmental dependence of the stellar mass fundamental plane of early-type galaxies
Hou, Lei
2016-01-01
Aims. We investigate the environmental dependence of the stellar mass fundamental plane (FP$_*$) using the early-type galaxy sample from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7). Methods. The FP$_*$ is calculated by replacing the luminosity in the fundamental plane (FP) with stellar mass. Based on the SDSS group catalog, we characterize the galaxy environment according to the mass of the host dark matter halo and the position in the halo. In halos with the same mass bin, the color distributions of central and satellite galaxies are different. Therefore, we calculate FP$_*$ coefficients of galaxies in different environments and compare them with those of the FP to study the contribution of the stellar population. Results. We find that coefficient $a$ of the FP$_*$ is systematically larger than that of the FP, but coefficient $b$ of the FP$_*$ is similar to the FP. Moreover, the environmental dependence of the FP$_*$ is similar to that of the FP. For central galaxies, FP$_*$ coefficients are signi...
Star cluster life-times: dependence on mass, radius and environment
Gieles, Mark; Baumgardt, Holger
2007-01-01
The dissolution time (t_dis) of clusters in a tidal field does not scale with the ``classical'' expression for the relaxation time. First, the scaling with N, and hence cluster mass, is shallower due to the finite escape time of stars. Secondly, the cluster half-mass radius is of little importance. This is due to a balance between the relative tidal field strength and internal relaxation, which have an opposite effect on t_dis, but of similar magnitude. When external perturbations, such as encounters with giant molecular clouds (GMC) are important, t_dis for an individual cluster depends strongly on radius. The mean dissolution time for a population of clusters, however, scales in the same way with mass as for the tidal field, due to the weak dependence of radius on mass. The environmental parameters that determine t_dis are the tidal field strength and the density of molecular gas. We compare the empirically derived t_dis of clusters in six galaxies to theoretical predictions and argue that encounters with G...
Anomalous Chiral Superfluidity
Lublinsky, Michael(Physics Department, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel); Zahed, Ismail
2009-01-01
We discuss both the anomalous Cartan currents and the energy-momentum tensor in a left chiral theory with flavour anomalies as an effective theory for flavored chiral phonons in a chiral superfluid with the gauged Wess-Zumino-Witten term. In the mean-field (leading tadpole) approximation the anomalous Cartan currents and the energy momentum tensor take the form of constitutive currents in the chiral superfluid state. The pertinence of higher order corrections and the Adler-Bardeen theorem is ...
PRIMUS: The dependence of AGN accretion on host stellar mass and color
Aird, James; Moustakas, John; Blanton, Michael R; Burles, Scott M; Cool, Richard J; Eisenstein, Daniel J; Smith, M Stephen M; Wong, Kenneth C; Zhu, Guangtun
2011-01-01
We present evidence that the incidence of active galactic nuclei (AGN) and the distribution of their accretion rates do not depend on the stellar masses of their host galaxies, contrary to previous studies. We use hard (2-10 keV) X-ray data from three extragalactic fields (XMM-LSS, COSMOS and ELAIS-S1) with redshifts from the PRIsm MUlti-object Survey (PRIMUS) to identify 264 AGN with L_{2-10 keV}=10^{42-44} erg/s within a parent sample of ~25,000 galaxies at 0.2
The Outcome of Supernovae in Massive Binaries; Removed Mass, and its Separation Dependence
Hirai, Ryosuke; Yamada, Shoichi
2014-01-01
The majority of massive stars are formed in binary systems. It is hence reasonable to expect that most core-collapse supernovae (CCSNe) take place in binaries and the existence of a companion star may leave some imprints in observed features. Having this in mind, we have conducted two-dimensional hydrodynamical simulations of the collisions of CCSNe ejecta with the companion star in an almost-equal-mass ($\\sim 10M_\\odot$) binary to find out possible consequences of such events. In particular we pay attention to the amount of mass removed and its dependence on the binary separation. In contrast to the previous surmise, we find that the companion mass is stripped not by momentum transfer but by shock heating. Up to $25\\%$ of the original mass can be removed for the closest separations and the removed mass decreases as $M_{ub} \\propto a^{-4.2}$ with the binary separation $a$. By performing some experimental computations with artificially-modified densities of incident ejecta, we show that if the velocity of ejec...
Anomalous Growth of Aging Populations
Grebenkov, Denis S.
2016-04-01
We consider a discrete-time population dynamics with age-dependent structure. At every time step, one of the alive individuals from the population is chosen randomly and removed with probability q_k depending on its age, whereas a new individual of age 1 is born with probability r. The model can also describe a single queue in which the service order is random while the service efficiency depends on a customer's "age" in the queue. We propose a mean field approximation to investigate the long-time asymptotic behavior of the mean population size. The age dependence is shown to lead to anomalous power-law growth of the population at the critical regime. The scaling exponent is determined by the asymptotic behavior of the probabilities q_k at large k. The mean field approximation is validated by Monte Carlo simulations.
Metallicity dependence of high-mass X-ray binary populations
Douna, V. M.; Pellizza, L. J.; Mirabel, I. F.; Pedrosa, S. E.
2015-07-01
Context. High-mass X-ray binaries (HMXBs) might have contributed a non-negligible fraction of the energy feedback to the interstellar and intergalactic media at high redshift, becoming important sources for the heating and ionization history of the Universe. However, the importance of this contribution depends on the hypothesized increase in the number of HMXBs formed in low-metallicity galaxies and in their luminosities. Aims: In this work we test the aforementioned hypothesis, and quantify the metallicity dependence of HMXB population properties. Methods: We compile from the literature a large set of data on the sizes and X-ray luminosities of HMXB populations in nearby galaxies with known metallicities and star formation rates. We use Bayesian inference to fit simple Monte Carlo models that describe the metallicity dependence of the size and luminosity of the HMXB populations. Results: We find that HMXBs are typically ten times more numerous per unit star formation rate in low-metallicity galaxies (12 + log (O / H) < 8, namely <20% solar) than in solar-metallicity galaxies. The metallicity dependence of the luminosity of HMXBs is small compared to that of the population size. Conclusions: Our results support the hypothesis that HMXBs are more numerous in low-metallicity galaxies, implying the need to investigate the feedback in the form of X-rays and energetic mass outflows of these high-energy sources during cosmic dawn.
Parkin loss leads to PARIS-dependent declines in mitochondrial mass and respiration.
Stevens, Daniel A; Lee, Yunjong; Kang, Ho Chul; Lee, Byoung Dae; Lee, Yun-Il; Bower, Aaron; Jiang, Haisong; Kang, Sung-Ung; Andrabi, Shaida A; Dawson, Valina L; Shin, Joo-Ho; Dawson, Ted M
2015-09-15
Mutations in parkin lead to early-onset autosomal recessive Parkinson's disease (PD) and inactivation of parkin is thought to contribute to sporadic PD. Adult knockout of parkin in the ventral midbrain of mice leads to an age-dependent loss of dopamine neurons that is dependent on the accumulation of parkin interacting substrate (PARIS), zinc finger protein 746 (ZNF746), and its transcriptional repression of PGC-1α. Here we show that adult knockout of parkin in mouse ventral midbrain leads to decreases in mitochondrial size, number, and protein markers consistent with a defect in mitochondrial biogenesis. This decrease in mitochondrial mass is prevented by short hairpin RNA knockdown of PARIS. PARIS overexpression in mouse ventral midbrain leads to decreases in mitochondrial number and protein markers and PGC-1α-dependent deficits in mitochondrial respiration. Taken together, these results suggest that parkin loss impairs mitochondrial biogenesis, leading to declining function of the mitochondrial pool and cell death. PMID:26324925
The Optical-UV Emissivity of Quasars: Dependence on Black Hole Mass and Radio Loudness
Shankar, Francesco; Calderone, Giorgio; Knigge, Christian; Matthews, James; Buckland, Rachel; Hryniewicz, Krzysztof; Sivakoff, Gregory; Dai, Xinyu; Richardson, Kayleigh; Riley, Jack; Gray, James; La Franca, Fabio; Altamirano, Diego; Croston, Judith; Gandhi, Poshak; Hönig, Sebastian; McHardy, Ian; Middleton, Matthew
2016-02-01
We analyzed a large sample of radio-loud and radio-quiet quasar spectra at redshift 1.0 ≤ z ≤ 1.2 to compare the inferred underlying quasar continuum slopes (after removal of the host galaxy contribution) with accretion disk models. The latter predict redder (decreasing) α3000 continuum slopes ({L}ν \\propto {ν }α at 3000 Å) with increasing black hole mass, bluer α3000 with increasing luminosity at 3000 Å, and bluer α3000 with increasing spin of the black hole, when all other parameters are held fixed. We find no clear evidence for any of these predictions in the data. In particular, we find the following. (i) α3000 shows no significant dependence on black hole mass or luminosity. Dedicated Monte Carlo tests suggest that the substantial observational uncertainties in the black hole virial masses can effectively erase any intrinsic dependence of α3000 on black hole mass, in line with some previous studies. (ii) The mean slope α3000 of radio-loud sources, thought to be produced by rapidly spinning black holes, is comparable to, or even redder than, that of radio-quiet quasars. Indeed, although quasars appear to become more radio loud with decreasing luminosity, we still do not detect any significant dependence of α3000 on radio loudness. The predicted mean α3000 slopes tend to be bluer than in the data. Disk models with high inclinations and dust extinction tend to produce redder slopes closer to empirical estimates. Our mean α3000 values are close to the ones independently inferred at z < 0.5, suggesting weak evolution with redshift, at least for moderately luminous quasars.
Meier, Matthias M. M.; Cloquet, Christophe; Marty, Bernard
2016-06-01
We have measured the concentration, isotopic composition and thermal release profiles of Mercury (Hg) in a suite of meteorites, including both chondrites and achondrites. We find large variations in Hg concentration between different meteorites (ca. 10 ppb to 14,000 ppb), with the highest concentration orders of magnitude above the expected bulk solar system silicates value. From the presence of several different Hg carrier phases in thermal release profiles (150-650 °C), we argue that these variations are unlikely to be mainly due to terrestrial contamination. The Hg abundance of meteorites shows no correlation with petrographic type, or mass-dependent fractionation of Hg isotopes. Most carbonaceous chondrites show mass-independent enrichments in the odd-numbered isotopes 199Hg and 201Hg. We show that the enrichments are not nucleosynthetic, as we do not find corresponding nucleosynthetic deficits of 196Hg. Instead, they can partially be explained by Hg evaporation and redeposition during heating of asteroids from primordial radionuclides and late-stage impact heating. Non-carbonaceous chondrites, most achondrites and the Earth do not show these enrichments in vapor-phase Hg. All meteorites studied here have however isotopically light Hg (δ202Hg = ∼-7 to -1) relative to the Earth's average crustal values, which could suggest that the Earth has lost a significant fraction of its primordial Hg. However, the late accretion of carbonaceous chondritic material on the order of ∼2%, which has been suggested to account for the water, carbon, nitrogen and noble gas inventories of the Earth, can also contribute most or all of the Earth's current Hg budget. In this case, the isotopically heavy Hg of the Earth's crust would have to be the result of isotopic fractionation between surface and deep-Earth reservoirs.
Wang, Zhuhong; Chen, Jiubin; Feng, Xinbin; Hintelmann, Holger; Yuan, Shengliu; Cai, Hongming; Huang, Qiang; Wang, Shuxiao; Wang, Fengyang
2015-11-01
The isotopic composition of mercury (Hg) is increasingly used to constrain the sources and pathways of this metal in the atmosphere. Though China has the highest Hg production, consumption and emission in the world, Hg isotope ratios are rarely reported for Chinese wet deposition. In this study, we examined, for the first time outside North America, both mass-dependent fractionation (MDF, expressed as δ202Hg) and mass-independent fractionation of odd (odd-MIF, Δ199Hg) and even (even-MIF, Δ200Hg) Hg isotopes in 15 precipitation samples collected from September 2012 to August 2013 in Guiyang (SW China). All samples displayed significant negative δ202Hg (-0.44 ∼ -4.27‰), positive Δ199Hg (+0.19 to +1.16‰) and slightly positive Δ200Hg (-0.01‰ to +0.20‰). Potential sources of Hg in precipitation were identified by coupling both MDF and MIF of Hg isotopes with a back-trajectory model. The results showed that local emission from coal-fired power plants and cement plants and western long-range transportation are two main contributing sources, while the contribution of Hg from south wind events would be very limited on an annual basis. The relatively lower Δ200Hg values in Guiyang precipitation may indicate a dilution effect by local sources and/or insignificant even-MIF in the tropopause contribution of this subtropical region. Our study demonstrates the usefulness of isotope fractionation, especially MIF for tracing sources and pathways of Hg in the atmosphere.
Anomalous transport effects in magnetically-confined plasma columns
The evolution of density structure in a magnetized plasma column is analyzed accounting for anomalous diffusion due to the lower hybrid drift instability. The plasma column is found to be divided into regions of classical, anomalous, and intermediate diffusivity. The bulk behavior, described in terms of radial confinement time, depends most sensitively upon the particle line density (ion/cm). For broad plasmas (large line density), the transport is characteristic of classical diffusion, and for slender plasmas (small line density) the transport is characteristic of anomalous diffusion. For intermediate line densities, the transport undertakes a rapid transition from classical to anomalous. Correlations between the theoretical results and past experiments are described
Quantum information entropies for position-dependent mass Schrödinger problem
Yañez-Navarro, G. [Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Edificio 9, UPALM, Mexico D. F. 07738 (Mexico); Sun, Guo-Hua, E-mail: sunghdb@yahoo.com [Centro Universitario Valle de Chalco, Universidad Autónoma del Estado de México, Valle de Chalco Solidaridad, Estado de México, 56615 (Mexico); Dytrych, T., E-mail: tdytrych@gmail.com [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001 (United States); Launey, K.D., E-mail: kristina@baton.phys.lsu.edu [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001 (United States); Dong, Shi-Hai, E-mail: dongsh2@yahoo.com [Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Edificio 9, UPALM, Mexico D. F. 07738 (Mexico); Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001 (United States); Draayer, J.P., E-mail: draayer@sura.org [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001 (United States)
2014-09-15
The Shannon entropy for the position-dependent Schrödinger equation for a particle with a nonuniform solitonic mass density is evaluated in the case of a trivial null potential. The position S{sub x} and momentum S{sub p} information entropies for the three lowest-lying states are calculated. In particular, for these states, we are able to derive analytical solutions for the S{sub x} entropy as well as for the Fourier transformed wave functions, while the S{sub p} quantity is calculated numerically. We notice the behavior of the S{sub x} entropy, namely, it decreases as the mass barrier width narrows and becomes negative beyond a particular width. The negative Shannon entropy exists for the probability densities that are highly localized. The mass barrier determines the stability of the system. The dependence of S{sub p} on the width is contrary to the one for S{sub x}. Some interesting features of the information entropy densities ρ{sub s}(x) and ρ{sub s}(p) are demonstrated. In addition, the Bialynicki-Birula–Mycielski (BBM) inequality is tested for a number of states and found to hold for all the cases.
Quantum information entropies for position-dependent mass Schrödinger problem
The Shannon entropy for the position-dependent Schrödinger equation for a particle with a nonuniform solitonic mass density is evaluated in the case of a trivial null potential. The position Sx and momentum Sp information entropies for the three lowest-lying states are calculated. In particular, for these states, we are able to derive analytical solutions for the Sx entropy as well as for the Fourier transformed wave functions, while the Sp quantity is calculated numerically. We notice the behavior of the Sx entropy, namely, it decreases as the mass barrier width narrows and becomes negative beyond a particular width. The negative Shannon entropy exists for the probability densities that are highly localized. The mass barrier determines the stability of the system. The dependence of Sp on the width is contrary to the one for Sx. Some interesting features of the information entropy densities ρs(x) and ρs(p) are demonstrated. In addition, the Bialynicki-Birula–Mycielski (BBM) inequality is tested for a number of states and found to hold for all the cases
Hao, Weiqiang; Wang, Junde; Zhang, Xiangmin
2006-12-01
In order to investigate the concentration dependence of mass transfer coefficients in RPLC, experimental breakthrough curves obtained by staircase frontal analysis (FA) were fitted to the simplified models such as multiplate (MP) model, equilibrium dispersive (ED) model, and transport model, and the sophisticated models such as lumped pore diffusion (POR) model and general rate (GR) model. The MP model was used to obtain the initial guesses of the parameters of the ED and the transport models. Then the best values were obtained by minimizing the differences between theoretical and experimental values with a nonlinear fitting procedure. The values of the parameters of the POR and the GR models can be calculated by using the expressions derived from the plate height equations, which was further validated by using the fitting method. It was found that the mass transfer coefficients would depend on the solute concentration. This can be ascribed to the surface diffusivity, which correlates with the concentration and is lumped into the mass transfer coefficients for both simplified and sophisticated models. PMID:17305235
Bohr Hamiltonian with a deformation-dependent mass term: physical meaning of the free parameter
Bonatsos, Dennis; Petrellis, D
2015-01-01
Embedding of the 5-dimensional (5D) space of the Bohr Hamiltonian with a deformation-dependent mass (DDM) into a 6-dimensional (6D) space shows that the free parameter in the dependence of the mass on the deformation is connected to the curvature of the 5D space, with the special case of constant mass corresponding to a flat 5D space. Comparison of the DDM Bohr Hamiltonian to the 5D classical limit of Hamiltonians of the 6D interacting boson model (IBM), shows that the DDM parameter is proportional to the strength of the pairing interaction in the U(5) (vibrational) symmetry limit, while it is proportional to the quadrupole-quadrupole interaction in the SU(3) (rotational) symmetry limit, and to the difference of the pairing interactions among s, d bosons and d bosons alone in the O(6) (gamma-soft) limit. The presence of these interactions leads to a curved 5D space in the classical limit of IBM, in contrast to the flat 5D space of the original Bohr Hamiltonian, which is made curved by the introduction of the ...
An Update on the Non-Mass-Dependent Isotope Fractionation under Thermal Gradient
Sun, Tao; Niles, Paul; Bao, Huiming; Socki, Richard; Liu, Yun
2013-01-01
Mass flow and compositional gradient (elemental and isotope separation) occurs when flu-id(s) or gas(es) in an enclosure is subjected to a thermal gradient, and the phenomenon is named thermal diffusion. Gas phase thermal diffusion has been theoretically and experimentally studied for more than a century, although there has not been a satisfactory theory to date. Nevertheless, for isotopic system, the Chapman-Enskog theory predicts that the mass difference is the only term in the thermal diffusion separation factors that differs one isotope pair to another,with the assumptions that the molecules are spherical and systematic (monoatomic-like structure) and the particle collision is elastic. Our previous report indicates factors may be playing a role because the Non-Mass Dependent (NMD) effect is found for both symmetric and asymmetric, linear and spherical polyatomic molecules over a wide range of temperature (-196C to +237C). The observed NMD phenomenon in the simple thermal-diffusion experiments demands quantitative validation and theoretical explanation. Besides the pressure and temperature dependency illustrated in our previous reports, efforts are made in this study to address issues such as the role of convection or molecular structure and whether it is a transient, non-equilibrium effect only.
Quark mass dependence of H-dibaryon in $\\Lambda\\Lambda$ scattering
Yamaguchi, Yasuhiro
2016-01-01
We study the quark mass dependence of the H-dibaryon in the strangeness $S=-2$ baryon-baryon scattering. A low-energy effective field theory is used to describe the coupled-channel scattering, in which the quark mass dependence is incorporated so as to reproduce the lattice QCD data in the SU(3) limit. We point out the existence of the Castillejo-Dalitz-Dyson (CDD) pole in the $\\Lambda\\Lambda$ scattering amplitude below the threshold in the SU(3) limit, which may cause the Ramsauer-Townsend effect near the $N\\Xi$ threshold at the physical point. The H-dibaryon is unbound at the physical point, and a resonance appears just below the $N\\Xi$ threshold. As a consequence of the coupled-channel dynamics, the pole associated with the resonance is not continuously connected to the bound state in the SU(3) limit. Through the extrapolation in quark masses, we show that the unitary limit of the $\\Lambda\\Lambda$ scattering is achieved between the physical point and the SU(3) limit. We discuss the possible realization of ...
Anomalous diffraction in hyperbolic materials
Alberucci, Alessandro; Boardman, Allan D; Assanto, Gaetano
2016-01-01
We demonstrate that light is subject to anomalous (i.e., negative) diffraction when propagating in the presence of hyperbolic dispersion. We show that light propagation in hyperbolic media resembles the dynamics of a quantum particle of negative mass moving in a two-dimensional potential. The negative effective mass implies time reversal if the medium is homogeneous. Such property paves the way to diffraction compensation, spatial analogue of dispersion compensating fibers in the temporal domain. At variance with materials exhibiting standard elliptic dispersion, in inhomogeneous hyperbolic materials light waves are pulled towards regions with a lower refractive index. In the presence of a Kerr-like optical response, bright (dark) solitons are supported by a negative (positive) nonlinearity.
The Mass Dependance of Satellite Quenching in Milky Way-like Halos
Phillips, John I; Cooper, Michael C; Boylan-Kolchin, Michael; Bullock, James S; Tollerud, Erik
2014-01-01
Using the Sloan Digital Sky Survey, we examine the quenching of satellite galaxies around isolated Milky Way-like hosts in the local Universe. We find that the efficiency of satellite quenching around isolated galaxies is low and roughly constant over two orders of magnitude in satellite stellar mass ($M_{*}$ = $10^{8.5}-10^{10.5} \\, M_{\\odot}$), with only $\\sim~20\\%$ of systems quenched as a result of environmental processes. While largely independent of satellite stellar mass, satellite quenching does exhibit clear dependence on the properties of the host. We show that satellites of passive hosts are substantially more likely to be quenched than those of star-forming hosts, and we present evidence that more massive halos quench their satellites more efficiently. These results extend trends seen previously in more massive host halos and for higher satellite masses. Taken together, it appears that galaxies with stellar masses larger than about $10^{8}~M_{\\odot}$ are uniformly resistant to environmental quench...
Orbital evolution of mass-transferring eccentric binary systems. I. Phase-dependent evolution
Dosopoulou, Fani
2016-01-01
Observations reveal that a large amount of close binary systems have a finite eccentricity. The time-evolution of the orbital semi-major axis and eccentricity of mass-transferring eccentric binary systems is an important part of binary evolution theory and has been widely studied. However, various different approaches and assumptions on the subject have made the literature difficult to comprehend and comparisons between different orbital element time-evolution equations not easy to make. Consequently, no self-consistent treatment of this phase has been ever included in binary population synthesis codes. In this paper, we present a general formalism to derive the time-evolution equations of the binary orbital elements, treating mass-loss and mass-transfer as perturbations to the general two-body problem. We present the self-consistent form of the perturbing acceleration and the phase-dependent time-evolution equations for the orbital elements under different mass-loss/transfer processes. First, we study the ca...
The Absence of an Environmental Dependence in the Mass-Metallicity Relation at z=2
Kacprzak, Glenn G; Nanayakkara, Themiya; Kobayashi, Chiaki; Tran, Kim-Vy H; Kewley, Lisa J; Glazebrook, Karl; Spitler, Lee; Taylor, Philip; Cowley, Michael; Labbé, Ivo; Straatman, Caroline; Tomczak, Adam
2015-01-01
We investigate the environmental dependence of the mass-metallicity relation at z=2 with MOSFIRE/Keck as part of the ZFIRE survey. Here, we present the chemical abundance of a Virgo-like progenitor at z=2.095 that has an established red sequence. We identified 43 cluster ($=2.095\\pm0.004$) and 74 field galaxies ($=2.195\\pm0.083$) for which we can measure metallicities. For the first time, we show that there is no discernible difference between the mass-metallicity relation of field and cluster galaxies to within 0.02dex. Both our field and cluster galaxy mass-metallicity relations are consistent with recent field galaxy studies at z~2. We present hydrodynamical simulations for which we derive mass-metallicity relations for field and cluster galaxies. We find at most a 0.1dex offset towards more metal-rich simulated cluster galaxies. Our results from both simulations and observations are suggestive that environmental effects, if present, are small and are secondary to the ongoing inflow and outflow processes t...