99,411 research outputs found
Global behavior of cosmological dynamics with interacting Veneziano ghost
In this paper, we shall study the dynamical behavior of the universe
accelerated by the so called Veneziano ghost dark energy component locally and
globally by using the linearization and nullcline method developed in this
paper. The energy density is generalized to be proportional to the Hawking
temperature defined on the trapping horizon instead of Hubble horizon of the
Friedmann-Robertson-Walker (FRW) universe. We also give a prediction of the
fate of the universe and present the bifurcation phenomenon of the dynamical
system of the universe. It seems that the universe could be dominated by dark
energy at present in some region of the parameter space.Comment: 8 pages, 7 figures, accepted for publication in JHE
Equilibrium states of the pressure function for products of matrices
Let be a non-trivial family of complex
matrices, in the sense that for any , there exists such that . Let be the pressure function of . We show
that for each , there are at most ergodic -equilibrium states of
, and each of them satisfies certain Gibbs property.Comment: 12 pages. To appear in DCD
Anticipating a New Golden Age
The standard model of fundamental interactions is remarkably successful, but
it leaves an unfinished agenda. Several major questions seem ripe for
exploration in the near future. I anticipate that the coming decade will be a
Golden Age of discovery in fundamental physics.Comment: 25 pages, 15 figures. Version 3: Added references, caption to Figure
14 correcte
A citizen-science approach to muon events in imaging atmospheric Cherenkov telescope data: the Muon Hunter
Event classification is a common task in gamma-ray astrophysics. It can be
treated with rapidly-advancing machine learning algorithms, which have the
potential to outperform traditional analysis methods. However, a major
challenge for machine learning models is extracting reliably labelled training
examples from real data. Citizen science offers a promising approach to tackle
this challenge.
We present "Muon Hunter", a citizen science project hosted on the Zooniverse
platform, where VERITAS data are classified multiple times by individual users
in order to select and parameterize muon events, a product from cosmic ray
induced showers. We use this dataset to train and validate a convolutional
neural-network model to identify muon events for use in monitoring and
calibration. The results of this work and our experience of using the
Zooniverse are presented.Comment: 8 pages, 3 figures, in Proceedings of the 35th International Cosmic
Ray Conference (ICRC 2017), Busan, South Kore
Single spin detection by qubit SWAP to a molecular nanomagnet
Spin state detection is a key but very challenging step for any spin-based
solid-state quantum computing technology. In fullerene based quantum computer
technologies, we here propose to detect the single spin inside a fullerene by
transferring the quantum information from the endohedral spin to the ground
states of a molecular nanomagnet Fe, with large spin S=10. We show how to
perform the required SWAP operation and how to read out the information through
state-of-the-art techniques such as micro-SQUID.Comment: Europhysics Letters 69,699 (2005
On the signature of certain intersection forms
We prove a conjecture of Zuber on the signature of intersection froms
associated with affine algebras of type A.Comment: 10 pages, Amste
A new approach to investigate wave dissipation in viscoelastic tubes: Application of wave intensity analysis
Wave dissipation in elastic and viscoelastic medium has been investigated extensively in the frequency domain. The aim of this study is to examine the pattern of wave dissipation in the time-domain using wave intensity analysis. A single semi-sinusoidal pulse was generated in 8 mm and 16 mm diameter tubes; each is of 200 cm in length. Pressure and flow measurements were taken at intervals of 5 cm along the tube. In order to examine the effect of the wall mechanical properties on wave dissipation, we also modified the wall of the 16 mm tube; a thread of strong cotton was wound with a pitch of approximately 30deg around the circumference of the tube in the longitudinal direction. The separated forward pressure, wave intensity and wave energy were calculated using wave intensity analysis. The amplitudes of the forward pressure wave, wave intensity and wave energy dissipated exponentially with distance. In the 8 mm diameter tube, the dissipation of forward pressure, wave intensity and wave energy were greater than those in 16 mm tube. For the same sized of tube, there was no significant difference in the dissipation of forward pressure, wave intensity and wave energy between the modified and normal wall tubes. It is concluded that the size of tube has a significant effect on the wave dissipation but the mechanical properties of the wall do not have a discernable effect on wave dissipatio
Determination of wave intensity in flexible tubes using measured diameter and velocity
Wave intensity (WI) is a hemodynamics index, which is the product of changes in pressure and velocity across the wave-front. Wave Intensity Analysis, which is a time domain technique allows for the separation of running waves into their forward and backward directions and traditionally uses the measured pressure and velocity waveforms. However, due to the possible difficulty in obtaining reliable pressure waveforms non-invasively, investigating the use of wall displacement instead of pressure signals in calculating WI may have clinical merits. In this paper, we developed an algorithm in which we use the measured diameter of flexible tube's wall and flow velocity to separate the velocity waveform into its forward and backward directions. The new algorithm is also used to separate wave intensity into its forward and backward directions. In vitro experiments were carried out in two sized flexible tubes, 12 mm and 16 mm in diameters, each is of 2 m in length. Pressure, velocity and diameter were taken at three measuring sites. A semi-sinusoidal wave was generated using a piston pump, which ejected 40 cc water into each tube. The results show that separated wave intensity into the forward and backward directions of the new algorithm using the measured diameter and velocity are almost identical in shape to those traditionally using the measured pressure and velocity. We conclude that the new algorithm presented in this work, could have clinical advantages since the required information can be obtained non-invasively
Recommended from our members
Advances and challenges in commercializing radiative cooling
Radiative cooling (RC) dissipates terrestrial heat to outer space through the atmospheric window, without external energy input and production of environmental pollutants. More and more efforts have been devoted to this clean promising cooling technology; thus diverse radiative coolers have emerged. However, the performance, cost, and effectiveness of various radiative coolers are not exactly the same. In addition, the large-scale application of RC technology is impeded by the low energy density, uncontrollable cooling power, and limited sky-facing area. Here, we critically review the recent progress of RC technology, evaluate the cooling performance of various radiative coolers, and discuss the challenges and feasible solutions to commercialize RC technology. Furthermore, valuable insights are provided to make new breakthroughs in this field
- …