10,940 research outputs found
Gravitational resonances on -brane
In this paper, we investigate various -brane models and compare their
gravitational resonance structures with the corresponding general relativity
(GR)-branes. {Starting from some known GR-brane solutions}, we derive thick
-brane solutions such that the metric, scalar field, and scalar potential
coincide with those of the corresponding GR-branes. {We find that for branes
generated by a single or several canonical scalar fields, there is no obvious
distinction between the GR-branes and corresponding -branes in terms of
gravitational resonance structure.} Then we discuss the branes generated by
K-fields. In this case, there could exist huge differences between GR-branes
and -branes.Comment: 17 pages, 14 figures, published versio
The structure of -brane model
Recently, a family of interesting analytical brane solutions were found in
gravity with in Ref. [Phys. Lett. B 729, 127
(2014)]. In these solutions, inner brane structure can be turned on by tuning
the value of the parameter . In this paper, we investigate how the
parameter affects the localization and the quasilocalization of the
tensorial gravitons around these solutions. It is found that, in a range of
, despite the brane has an inner structure, there is no graviton
resonance. However, in some other regions of the parameter space, although the
brane has no internal structure, the effective potential for the graviton KK
modes has a singular structure, and there exists a series of graviton resonant
modes. The contribution of the massive graviton KK modes to the Newton's law of
gravity is discussed shortly.Comment: v2: 10 pages, 8 figures, to be published in EPJ
Joint Power Splitting and Secure Beamforming Design in the Wireless-powered Untrusted Relay Networks
In this work, we maximize the secrecy rate of the wireless-powered untrusted
relay network by jointly designing power splitting (PS) ratio and relay
beamforming with the proposed global optimal algorithm (GOA) and local optimal
algorithm (LOA). Different from the literature, artificial noise (AN) sent by
the destination not only degrades the channel condition of the eavesdropper to
improve the secrecy rate, but also becomes a new source of energy powering the
untrusted relay based on PS. Hence, it is of high economic benefits and
efficiency to take advantage of AN compared with the literature. Simulation
results show that LOA can achieve satisfactory secrecy rate performance
compared with that of GOA, but with less computation time.Comment: Submitted to GlobeCom201
Phenomenological relationship between eccentric and quasi-circular orbital binary black hole waveform
Eccentricity, an important parameter of gravitational waves, has been paid
more and more attention because it can reflect the dynamics of compact object
mergers. Obtaining an accurate and fast gravitational waveform template is of
great significance for the estimation of gravitational wave parameters. This
paper aims to do an extended study of the phenomenological fitting model
proposed by Setyawati and Ohme for adding eccentricity to quasi-circular
orbital waveforms. It can be applied to higher eccentricity up to e = 0.4. But
the higher the eccentricity, the less the accuracy. For e in [0, 0.1], it gives
an overlap of more than 99.99%. For e in [0.1, 0.2], it gives an overlap of
more than 99.9%. For e in [0.2, 0.3], it gives an overlap of more than 99%. For
e in [0.3, 0.4], it gives an overlap of more than 90%. The reason for these
phenomena is that the larger the eccentricity, the larger the deviation of the
eccentricity estimator from the cosine function due to the large change in the
morphology of the eccentric waveform, and the worse the fitting effect of the
model. It can be applied to higher-order modes and gives the same overlap
behavior. After adding a shift parameter, it can be applied to spin-aligned or
spin-antialigned waveforms. After obtaining spin-precessing effect, it can be
applied to the spin-precessing case. In summary, non-spining, spin-aligned,
spin-antialigned or spin-precessing waveforms with eccentricity can be
constructed from quasi-circular non-spining waveforms by the phenomenological
model, which is not only helpful for us to quickly construct phenomenological
gravitational wave templates, but also reveals a phenomenological and universal
relationship between eccentric waveform and quasi-circular orbital waveform.Comment: 19 pages, 18 figure
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