114,542 research outputs found

    Reply to ``Comment on `On the inconsistency of the Bohm-Gadella theory with quantum mechanics'''

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    In this reply, we show that when we apply standard distribution theory to the Lippmann-Schwinger equation, the resulting spaces of test functions would comply with the Hardy axiom only if classic results of Paley and Wiener, of Gelfand and Shilov, and of the theory of ultradistributions were wrong. As well, we point out several differences between the ``standard method'' of constructing rigged Hilbert spaces in quantum mechanics and the method used in Time Asymmetric Quantum Theory.Comment: 13 page

    Quantitative Flow Field Imaging about a Hydrophobic Sphere Impacting on a Free Surface

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    This fluid dynamics video shows the impact of a hydrophobic sphere impacting a water surface. The sphere has a mass ratio of m* = 1.15, a wetting angle of 110 degrees, a diameter of 9.5 mm, and impacts the surface with a Froude number of Fr = 9.2. The first sequence shows an impact of a sphere on the free surface illustrating the formation of the splash crown and air cavity. The cavity grows both in the axial and radial direction until it eventually collapses at a point roughly half of the distance from the free surface to the sphere, which is known as the pinch-off point. The second set of videos shows a sphere impacting the free surface under the same conditions using Particle Image Velocimetry (PIV) to quantify the flow field. A laser sheet illuminates the mid-plane of the sphere, and the fluid is seeded with particles whose motion is captured by a high-speed video camera. Velocity fields are then calculated from the images. The video sequences from left to right depict the radial velocity, the axial velocity, and the vorticity respectively in the flow field. The color bar on the far left indicates the magnitude of the velocity and vorticity. All videos were taken at 2610 fps and the PIV data was processed using a 16 x 16 window with a 50% overlap.Comment: American Physical Society Division of Fluid Dynamics 2008 Annual Meeting Replaced previous version because abstract had LaTex markup and was too long, missing periods on middle initial of first two name

    Performance of novel silicon n-in-p planar Pixel Sensors

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    The performance of novel n-in-p planar pixel detectors, designed for future upgrades of the ATLAS Pixel system is presented. The n-in-p silicon sensors technology is a promising candidate for the pixel upgrade thanks to its radiation hardness and cost effectiveness, that allow for enlarging the area instrumented with pixel detectors. The n-in-p modules presented here are composed of pixel sensors produced by CiS connected by bump-bonding to the ATLAS readout chip FE-I3. The characterization of these devices has been performed before and after irradiation up to a fluence of 5 x 10**15 1 MeV neq cm-2 . Charge collection measurements carried out with radioactive sources have proven the functioning of this technology up to these particle fluences. First results from beam test data with a 120 GeV/c pion beam at the CERN-SPS are also discussed, demonstrating a high tracking efficiency of (98.6 \pm 0.3)% and a high collected charge of about 10 ke for a device irradiated at the maximum fluence and biased at 1 kV.Comment: Preprint submitted to Nuclear Instruments and Methods A. 7 pages, 13 figure

    The rigged Hilbert space approach to the Lippmann-Schwinger equation. Part II: The analytic continuation of the Lippmann-Schwinger bras and kets

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    The analytic continuation of the Lippmann-Schwinger bras and kets is obtained and characterized. It is shown that the natural mathematical setting for the analytic continuation of the solutions of the Lippmann-Schwinger equation is the rigged Hilbert space rather than just the Hilbert space. It is also argued that this analytic continuation entails the imposition of a time asymmetric boundary condition upon the group time evolution, resulting into a semigroup time evolution. Physically, the semigroup time evolution is simply a (retarded or advanced) propagator.Comment: 32 pages, 3 figure

    Derivation of the Planck Spectrum for Relativistic Classical Scalar Radiation from Thermal Equilibrium in an Accelerating Frame

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    The Planck spectrum of thermal scalar radiation is derived suggestively within classical physics by the use of an accelerating coordinate frame. The derivation has an analogue in Boltzmann's derivation of the Maxwell velocity distribution for thermal particle velocities by considering the thermal equilibrium of noninteracting particles in a uniform gravitational field. For the case of radiation, the gravitational field is provided by the acceleration of a Rindler frame through Minkowski spacetime. Classical zero-point radiation and relativistic physics enter in an essential way in the derivation which is based upon the behavior of free radiation fields and the assumption that the field correlation functions contain but a single correlation time in thermal equilibrium. The work has connections with the thermal effects of acceleration found in relativistic quantum field theory.Comment: 23 page
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