65,383 research outputs found
Temporal networks: slowing down diffusion by long lasting interactions
Interactions among units in complex systems occur in a specific sequential
order thus affecting the flow of information, the propagation of diseases, and
general dynamical processes. We investigate the Laplacian spectrum of temporal
networks and compare it with that of the corresponding aggregate network.
First, we show that the spectrum of the ensemble average of a temporal network
has identical eigenmodes but smaller eigenvalues than the aggregate networks.
In large networks without edge condensation, the expected temporal dynamics is
a time-rescaled version of the aggregate dynamics. Even for single sequential
realizations, diffusive dynamics is slower in temporal networks. These
discrepancies are due to the noncommutability of interactions. We illustrate
our analytical findings using a simple temporal motif, larger network models
and real temporal networks.Comment: 5 pages, 2 figures, v2: minor revision + supplemental materia
Effect of limited statistics on higher order cumulants measurement in heavy-ion collision experiments
We have studied the effect of limited statistics of data on measurement of
the different order of cumulants of net-proton distribution assuming that the
proton and antiproton distributions follow Possionian and Binomial
distributions with initial parameters determined from experimental results for
two top center of mass energies ( and GeV)
in most central (%) AuAu collisions at Relativistic Heavy Ion Collider
(RHIC). In this simulation, we observe that the central values for higher order
cumulants have a strong dependence on event sample size and due to statistical
randomness the central values of higher order cumulants could become negative.
We also present a study on the determination of the statistical error on
cumulants using delta theorem, bootstrap and sub-group methods and verified
their suitability by employing a Monte Carlo procedure. Based on our study we
find that the bootstrap method provides a robust way for statistical error
estimation on high order cumulants. We also present the exclusion limits on the
minimum event statistics needed for determination of cumulants if the signal
strength (phase transition or critical point) is at a level of % and %
above the statistical level. This study will help the experiments to arrive at
the minimum required event statistics and choice of proper method for
statistical error estimation for high order cumulant measurements.Comment: 14 pages, 16 figure
Two Jovian-Mass Planets in Earthlike Orbits
We report the discovery of two new planets: a 1.94 M_Jup planet in a 1.8-year
orbit of HD 5319, and a 2.51 M_Jup planet in a 1.1-year orbit of HD 75898. The
measured eccentricities are 0.12 for HD 5319 b and 0.10 for HD 75898 b, and
Markov Chain Monte Carlo simulations based on derived orbital parameters
indicate that the radial velocities of both stars are consistent with circular
planet orbits. With low eccentricity and 1 < a < 2 AU, our new planets have
orbits similar to terrestrial planets in the solar system. The radial velocity
residuals of both stars have significant trends, likely arising from substellar
or low-mass stellar companions.Comment: 32 pages, including 11 figures and 5 tables. Accepted by Ap
Making SPIFFI SPIFFIER: Upgrade of the SPIFFI instrument for use in ERIS and performance analysis from re-commissioning
SPIFFI is an AO-fed integral field spectrograph operating as part of SINFONI
on the VLT, which will be upgraded and reused as SPIFFIER in the new VLT
instrument ERIS. In January 2016, we used new technology developments to
perform an early upgrade to optical subsystems in the SPIFFI instrument so
ongoing scientific programs can make use of enhanced performance before ERIS
arrives in 2020. We report on the upgraded components and the performance of
SPIFFI after the upgrade, including gains in throughput and spatial and
spectral resolution. We show results from re-commissioning, highlighting the
potential for scientific programs to use the capabilities of the upgraded
SPIFFI. Finally, we discuss the additional upgrades for SPIFFIER which will be
implemented before it is integrated into ERIS.Comment: 20 pages, 12 figures. Proceedings from SPIE Astronomical Telescopes
and Instrumentation 201
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