Now showing items 3-22 of 729

  • Accretion-powered stellar winds as a solution to the stellar angular momentum problem 

    Matt, Sean P.; Pudritz, Ralph E. (American Astronomical Society, 2005-10-20)
    We compare the angular momentum extracted by a wind from a pre-main-sequence star to the torques arising from the interaction between the star and its Keplerian accretion disk. We find that the wind alone can counteract ...
  • Accretion-powered stellar winds. II. Numerical solutions for stellar wind torques 

    Matt, Sean P.; Pudritz, Ralph E. (Institute of Physics (IOP) Publishing, 2008-05-10)
    In order to explain the slow rotation observed in a large fraction of accreting pre-main-sequence stars (CTTSs), we explore the role of stellar winds in torquing down the stars. For this mechanism to be effective, the ...
  • Accretion-powered stellar winds. III. spin-equilibrium solutions 

    Matt, Sean P.; Pudritz, Ralph E., (Institute of Physics (IOP) Publishing, 2008-07-01)
    We compare the stellar wind torque calculated in a previous work (Paper II) to the spin-up and spin-down torques expected to arise from the magnetic interaction between a slowly rotating (∼10% of breakup) pre-main-sequence ...
  • Accuracy of stellar parameters of exoplanet-host stars determined from asteroseismology 

    Mulet-Marquis, C.; Baraffe, I.; Aigrain, Suzanne; Pont, F. (EDP Sciences, 2009)
    Context. In the context of the space-based mission CoRoT, devoted to asteroseismology and search for planet transits, we analyse the accuracy of fundamental stellar parameters (mass, radius, luminosity) that can be obtained ...
  • Accuracy tests of radiation schemes used in hot Jupiter global circulation models 

    Amundsen, David S.; Baraffe, I.; Tremblin, Pascal; Manners, James; Hayek, W.; Mayne, Nathan J.; Acreman, David M. (EDP Sciences for European Southern Observatory (ESO), 2014)
    The treatment of radiation transport in global circulation models (GCMs) is crucial to correctly describe Earth and exoplanet atmospheric dynamics processes. The two-stream approximation and correlated-k method are currently ...
  • An acoustic double fishnet using Helmholtz resonators 

    Murray, Alasdair R.J.; Summers, I.R.; Sambles, J. Roy; Hibbins, Alastair P. (Acoustical Society of America, 2014)
    The acoustic transmission of a closely spaced pair of patterned and perforated rigid plates is explored in air. The structure resembles an acoustic double fishnet design, with each plate modified such that the gap between ...
  • Acoustoelectric photoresponse in graphene 

    Bandhu, Lokeshwar; Nash, Geoffrey R.; Poole, Timothy (AIP Publishing, 2015-03-30)
    The acoustoelectric current in graphene has been investigated as a function of illumination, using blue (450nm) and red (735nm) light-emitting diodes (LEDs), and surface acoustic wave (SAW) intensity and frequency. The ...
  • Active absorption of electromagnetic pulses in a cavity 

    Horsley, S.A.R.; Foster, RN; Tyc, T; Philbin, Thomas G. (IOP Publishing, 2015-05-28)
    We show that a pulse of electromagnetic radiation launched into a cavity can be completely absorbed into an infinitesimal region of space, provided one has a high degree of control over the current flowing through this ...
  • Activity and magnetic field structure of the Sun-like planet-hosting star HD 1237 

    Alvarado-Gómez, JD; Hussain, GAJ; Grunhut, J; Fares, R; Donati, J-F; Alecian, E; Kochukhov, O; Oksala, M; Morin, J; Redfield, S; Cohen, O; Drake, JJ; Jardine, M; Matt, Sean P.; Petit, P; Walter, FM (EDP Sciences, 2015-10-01)
    We analyse the magnetic activity characteristics of the planet-hosting Sun-like star, HD 1237, using HARPS spectro-polarimetric time-series data. We find evidence of rotational modulation of the magnetic longitudinal field ...
  • Addendum: “The two-dimensional hydrogen atom revisited” [J. Math. Phys. 43, 4681 (2002)] 

    Parfitt, D.G.W.; Portnoi, M.E. (American Institute of Physics, 2003)
  • Adiabatic graph-state quantum computation 

    Antonio, B.; Markham, D.; Anders, Janet (Institute of Physics Publishing, 2014-11-26)
    Measurement-based quantum computation (MBQC) and holonomic quantum computation (HQC) are two very different computational methods. The computation in MBQC is driven by adaptive measurements executed in a particular order ...
  • Age Gradients in the Stellar Populations of Massive Star Forming Regions Based on a New Stellar Chronometer 

    Getman, KV; Feigelson, ED; Kuhn, MA; Broos, PS; Townsley, LK; Naylor, T; Povich, MS; Luhman, KL; Garmire, GP (American Astronomical Society, 2014-05-09)
    A major impediment to understanding star formation in massive star forming regions (MSFRs) is the absence of a reliable stellar chronometer to unravel their complex star formation histories. We present a new estimation of ...
  • Aharonov-Bohm quantum rings in high-Q microcavities 

    Alexeev, Arseny; Shelykh, I.A.; Portnoi, M.E. (American Physical Society, 2013)
    A single-mode microcavity with an embedded Aharonov-Bohm quantum ring, which is pierced by a magnetic flux and subjected to a lateral electric field, is studied theoretically. It is shown that external electric and magnetic ...
  • All-frequency reflectionlessness 

    Philbin, Thomas G. (IOP Publishing, 2015-12-11)
    We derive planar permittivity profiles that do not reflect perpendicularly exiting radiation of any frequency. The materials obey the Kramers-Kronig relations and have no regions of gain. Reduction of the Casimir force by ...
  • All-graphene photodetectors 

    Withers, Freddie; Bointon, Thomas H.; Craciun, Monica F.; Russo, Saverio (American Chemical Society, 2013)
    We investigate the optoelectronic properties of novel graphene/FeCl3-intercalated few-layer graphene (FeCl3-FLG, dubbed graphexeter) heterostructures using photovoltage spectroscopy. We observe a prominent photovoltage ...
  • All-Optical Generation of Surface Plasmons in Graphene 

    Constant, Thomas J.; Hornett, Samuel M.; Chang, D.E.; Hendry, Euan (Cornell University, 2015-05-01)
    Here we present an all-optical plasmon coupling scheme, utilising the intrinsic nonlinear optical response of graphene. We demonstrate coupling of free-space, visible light pulses to the surface plasmons in a planar, ...
  • An alternative calculation of the Casimir forces between birefringent plates 

    Philbin, Thomas G.; Leonhardt, Ulf (American Physical Society, 2008)
    Barash has calculated the Casimir forces between parallel birefringent plates with optical axes parallel to the plate boundaries [Izv. Vyssh. Uchebn.\ Zaved., Radiofiz., {\bf 12}, 1637 (1978)]. The interesting new feature ...
  • AMBER/VLTI high spectral resolution observations of the Brγ emitting region in HD 98922. A compact disc wind launched from the inner disc region 

    Caratti o Garatti, A; Tambovtseva, LV; Garcia Lopez, R; Kraus, Stefan; Schertl, D.; Grinin, VP; Weigelt, Gerd; Hofmann, Karl-Heinz; Massi, F.; Lagarde, S.; Vannier, M.; Malbet, F. (EDP Sciences, 2015-10)
    Context. High angular and spectral resolution observations can provide us with fundamental clues to the complex circumstellar structure of young stellar objects (YSOs) and to the physical processes taking place close to ...
  • AMBER/VLTI observations of the B[e] star MWC 300 

    Wang, Y.; Weigelt, Gerd; Kreplin, Alexander; Hofmann, Karl-Heinz; Kraus, Stefan; Miroshnichenko, A.S.; Schertl, D.; Chelli, A.; Domiciano de Souza, A.; Massi, F.; Robbe-Dubois, S. (EDP Sciences for European Southern Observatory (ESO), 2012)
    Aims. We study the enigmatic B[e] star MWC 300 to investigate its disk and binary with milli-arcsecond-scale angular resolution. Methods. We observed MWC 300 with the VLTI/AMBER instrument in the H and K bands and ...
  • AMI-LA radio continuum observations of Spitzer c2d small clouds and cores: Perseus region 

    Scaife, Anna M.M.; Hatchell, Jennifer; Davies, Matthew; Franzen, Thomas M.O.; Grainge, Keith J.B.; Hobson, Michael P.; Hurley-Walker, Natasha; Lasenby, Anthony N.; Olamaie, Malak; Perrott, Yvette C.; Pooley, Guy G.; Rodríguez-Gonzálvez, Carmen; Saunders, Richard D.E.; Schammel, Michel P.; Scott, Paul F.; Shimwell, Timothy; Titterington, David; Waldram, Elizabeth (Oxford University Press / Royal Astronomical Society, 2011)
    We present deep radio continuum observations of the cores identified as deeply embedded young stellar objects in the Perseus molecular cloud by the Spitzer c2d programme at a wavelength of 1.8 cm with the Arcminute Microkelvin ...