4,787 research outputs found
A pure-carbon ring transistor: The role of topology and structure
We report results on the rectification properties of a carbon nanotube (CNT)
ring transistor, contacted by CNT leads, whose novel features have been
recently communicated by Watanabe et al. [Appl. Phys. Lett. 78, 2928 (2001)].
This paper contains results which are validated by the experimental
observations. Moreover, we report on additional features of the transmission of
this ring device which are associated with the possibility of breaking the lead
inversion symmetry. The linear conductance displays a "chessboard"-like
behavior alternated with anomalous zero-lines which should be directly
observable in experiments. We are also able to discriminate in our results
structural properties (quasi-onedimensional confinement) from pure topological
effects (ring configuration), thus helping to gain physical intuition on the
rich ring phenomenology.Comment: 3 pages, 4 figure
Condensates induced by interband coupling in a double-well lattice
We predict novel inter-band physics for bosons in a double-well lattice. An
intrinsic coupling between the s and px band due to interaction gives rise to
larger Mott regions on the phase diagram at even fillings than the ones at odd
fillings. On the other hand, the ground state can form various types of
condensates, including a mixture of single-particle condensates of both bands,
a mixture of a single-particle condensate of one band and a pair-condensate of
the other band, and a pair-condensate composed of one particle from one band
and one hole from the other band. The predicted phenomena should be observable
in current experiments on double-well optical lattices.Comment: Published versio
Mapping the Americanization of English in Space and Time
As global political preeminence gradually shifted from the United Kingdom to
the United States, so did the capacity to culturally influence the rest of the
world. In this work, we analyze how the world-wide varieties of written English
are evolving. We study both the spatial and temporal variations of vocabulary
and spelling of English using a large corpus of geolocated tweets and the
Google Books datasets corresponding to books published in the US and the UK.
The advantage of our approach is that we can address both standard written
language (Google Books) and the more colloquial forms of microblogging messages
(Twitter). We find that American English is the dominant form of English
outside the UK and that its influence is felt even within the UK borders.
Finally, we analyze how this trend has evolved over time and the impact that
some cultural events have had in shaping it.Comment: 16 pages, 6 figures, 2 tables. Published versio
Spin induced multipole moments for the gravitational wave amplitude from binary inspirals to 2.5 Post-Newtonian order
Using the NRGR effective field theory formalism we calculate the remaining
source multipole moments necessary to obtain the spin contributions to the
gravitational wave amplitude to 2.5 Post-Newtonian (PN) order. We also
reproduce the tail contribution to the waveform linear in spin at 2.5PN arising
from the nonlinear interaction between the current quadrupole and the mass
monopole.Comment: 17 pages, 4 figures. v2 Minor changes, to appear in JCA
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