38,331 research outputs found
Differential Chow Form for Projective Differential Variety
In this paper, a generic intersection theorem in projective differential
algebraic geometry is presented. Precisely, the intersection of an irreducible
projective differential variety of dimension d>0 and order h with a generic
projective differential hyperplane is shown to be an irreducible projective
differential variety of dimension d-1 and order h. Based on the generic
intersection theorem, the Chow form for an irreducible projective differential
variety is defined and most of the properties of the differential Chow form in
affine differential case are established for its projective differential
counterpart. Finally, we apply the differential Chow form to a result of linear
dependence over projective varieties given by Kolchin.Comment: 17 page
Measuring the ratio of and couplings through production
For a generic Higgs boson, measuring the relative sign and magnitude of its
couplings with the and bosons is essential in determining its origin.
Such a test is also indispensable for the 125-GeV Higgs boson. We propose that
the ratio of the and couplings can be directly
determined through the production, where denotes a generic Higgs
boson, owing to the tree-level interference effect. While this is impractical
at the LHC due to the limited sensitivity, it can be done at future
colliders, such as a 500-GeV ILC with the beam polarization
in the and
channels. The discovery potential of a
general ratio and the power to discriminate it from the SM value are studied in
detail. Combining the cross section of with the
measurements of coupling at the HL-LHC, one can further improve the
sensitivity of .Comment: 24 pages, 10 figures, 2 table
Exact Cosmological Solutions of Theories via Hojman Symmetry
Nowadays, theory has been one of the leading modified gravity theories
to explain the current accelerated expansion of the universe, without invoking
dark energy. It is of interest to find the exact cosmological solutions of
theories. Besides other methods, symmetry has been proved as a powerful
tool to find exact solutions. On the other hand, symmetry might hint the deep
physical structure of a theory, and hence considering symmetry is also well
motivated. As is well known, Noether symmetry has been extensively used in
physics. Recently, the so-called Hojman symmetry was also considered in the
literature. Hojman symmetry directly deals with the equations of motion, rather
than Lagrangian or Hamiltonian, unlike Noether symmetry. In this work, we
consider Hojman symmetry in theories in both the metric and Palatini
formalisms, and find the corresponding exact cosmological solutions of
theories via Hojman symmetry. There exist some new solutions significantly
different from the ones obtained by using Noether symmetry in theories.
To our knowledge, they also have not been found previously in the literature.
This work confirms that Hojman symmetry can bring new features to cosmology and
gravity theories.Comment: 16 pages, revtex4; v2: discussions added, Nucl. Phys. B in press; v3:
published version. arXiv admin note: text overlap with arXiv:1505.0754
Coherent transport of armchair graphene constrictions
The coherent transport properties of armchair graphene nanoconstrictions(GNC)
are studied using tight-binding approach and Green's function method. We find a
non-bonding state at zero Fermi energy which results in a zero conductance
valley, when a single vacancy locates at of a perfect metallic
armchair graphene nanoribbon(aGNR). However, the non-bonding state doesn't
exist when a vacancy locates at y=3n, and the conductance behavior of lowest
conducting channel will not be affected by the vacancy. For the square-shaped
armchair GNC consisting of three metallic aGNR segments, resonant tunneling
behavior is observed in the single channel energy region. We find that the
presence of localized edge state locating at the zigzag boundary can affect the
resonant tunneling severely. A simplified one dimensional model is put forward
at last, which explains the resonant tunneling behavior of armchair GNC very
well.Comment: 6 pages, 11 figure
Fast DGT Based Receivers for GFDM in Broadband Channels
Generalized frequency division multiplexing (GFDM) is a recent multicarrier
5G waveform candidate with flexibility of pulse shaping filters. However, the
flexibility of choosing a pulse shaping filter may result in inter carrier
interference (ICI) and inter symbol interference (ISI), which becomes more
severe in a broadband channel. In order to eliminate the ISI and ICI, based on
discrete Gabor transform (DGT), in this paper, a transmit GFDM signal is first
treated as an inverse DGT (IDGT), and then a frequency-domain DGT is formulated
to recover (as a receiver) the GFDM signal. Furthermore, to reduce the
complexity, a suboptimal frequency-domain DGT called local DGT (LDGT) is
developed. Some analyses are also given for the proposed DGT based receivers.Comment: 28 pages, 8 figure
- β¦