19,642 research outputs found
Observational constraints on dark matter-dark energy scattering cross section
In this letter, we report precise and robust observational constraints on
dark matter-dark energy scattering cross section, using the latest data from
cosmic microwave background (CMB) Planck temperature and polarization, baryon
acoustic oscillations (BAO) measurements and weak gravitational lensing data
from Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS). The scattering
scenario consists of a pure momentum exchange between the dark components, and
we find at 95\% CL from the joint analysis
(CMB + BAO + CFHTLenS), for typical dark matter particle mass of the order 1-10
. We notice that the scattering among the dark components may
influence the growth of large scale structure in the Universe, leaving the
background cosmology unaltered.Comment: 6 pages, 4 figures, 1 table, Minor changes/additions, Matches the
version published in EPJ
Emergence of Complex Spatio-Temporal Behavior in Nonlinear Field Theories
We investigate the emergence of time-dependent nonperturbative configurations
during the evolution of nonlinear scalar field models with symmetric and
asymmetric double-well potentials. Complex spatio-temporal behavior emerges as
the system seeks to establish equipartition after a fast quench. We show that
fast quenches may dramatically modify the decay rate of metastable states in
first order phase transitions. We briefly suggest possible applications
incondensed matter systems and early universe cosmology.Comment: 6 pages, 8 figure
Resonant emergence of global and local spatiotemporal order in a nonlinear field model
We investigate the nonequilibrium evolution of a scalar field in (2+1)
dimensions. The field is set in a double-well potential in contact (open) or
not (closed) with a heat bath. For closed systems, we observe the synchronized
emergence of coherent spatiotemporal configurations, identified with oscillons.
This initial global ordering degenerates into localized order until all
oscillons disappear. We show that the synchronization is driven by resonant
parametric oscillations of the field's zero mode and that local ordering is
only possible outside equipartition. None of these orderings occur for open
systems.Comment: 4 pages, 5 figures, LaTeX, minor corrections to eqs. 1,3,
Flexible quantum circuits using scalable continuous-variable cluster states
We show that measurement-based quantum computation on scalable
continuous-variable (CV) cluster states admits more quantum-circuit flexibility
and compactness than similar protocols for standard square-lattice CV cluster
states. This advantage is a direct result of the macronode structure of these
states---that is, a lattice structure in which each graph node actually
consists of several physical modes. These extra modes provide additional
measurement degrees of freedom at each graph location, which can be used to
manipulate the flow and processing of quantum information more robustly and
with additional flexibility that is not available on an ordinary lattice.Comment: (v2) consistent with published version; (v1) 11 pages (9 figures
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