66 research outputs found
Null boundary gravitational charges from local Lorentz symmetries
In this paper, we revisit the null boundary gravitational charge in the
Newman-Penrose formalism with special emphasis on the charges from local
Lorentz transformations. We find that there is one more charge derived from the
local Lorentz transformation and the new charge is purely from the Holst term.
This reveals a remarkable fact that trivial terms which do not change classical
equations of motion can not only affect the boundary degrees of freedom through
their contributions to the boundary charges but also have their own rights to
create new boundary degrees of freedom.Comment: 10 page
Does Customersâ Emotion toward Voice-based Service AI Cause Negative Reactions? Empirical Evidence from a Call Center
Many companies are introducing voice-based artificial intelligence (AI) into their call centers. Little is known about the relationship between customersâ emotions to voice-based AI service and customersâ negative reactions. This study investigates the link between customersâ emotions toward voice-based AI service and customersâ negative reactions. Our results reveal that customersâ emotion toward voice-based AI service could significantly affect their complaint behavior, and customersâ complaints differ among emotion types. Customersâ negative and positive emotions toward voice-based AI services have a significantly negative and positive effect, respectively, on customer complaint behavior than neutral emotions. We also find that the exchange round of human-computer interaction moderates the effect of the customer emotion by attenuating its effect on customer complaints. This study is the first to empirically test the impact of customersâ emotions toward voice-based AI service on customersâ complaint behavior in the service industry
Notes on self-dual gravity
In this paper, we study self-dual gravity in the Newman-Penrose formalism. We
specify the self-dual solution space from the Newman-Unti solutions. We show
that the asymptotic symmetries of the self-dual gravity are still the
(extended) BMS symmetries. We transform the self-dual Taub-NUT solution into
the Newman-Unti gauge in analytical form.Comment: 11+4 page
Simulations of Triple Microlensing Events I: Detectability of a scaled Sun-Jupiter-Saturn System
Up to date, only 13 firmly established triple microlensing events have been
discovered, so the occurrence rates of microlensing two-planet systems and
planets in binary systems are still uncertain. With the upcoming space-based
microlensing surveys, hundreds of triple microlensing events will be detected.
To provide clues for future observations and statistical analyses, we initiate
a project to investigate the detectability of triple-lens systems with
different configurations and observational setups. As the first step, in this
work we develop the simulation software and investigate the detectability of a
scaled Sun-Jupiter-Saturn system with the recently proposed microlensing
telescope of the ``Earth 2.0 (ET)'' mission. We find that the detectability of
the scaled Sun-Jupiter-Saturn analog is about 1%. In addition, the presence of
the Jovian planet suppresses the detectability of the Saturn-like planet by
13% regardless of the adopted detection threshold. This
suppression probability could be at the same level as the Poisson noise of
future space-based statistical samples of triple-lenses, so it is inappropriate
to treat each planet separately during detection efficiency calculations.Comment: 14 pages, 11 figures, submitted to MNRAS, comments welcome
Measurement of Source Star Colors with the K2C9-CFHT Multi-color Microlensing Survey
K2 Campaign 9 (K2C9) was the first space-based microlensing parallax survey
capable of measuring microlensing parallaxes of free-floating planet candidate
microlensing events. Simultaneous to K2C9 observations we conducted the K2C9
Canada-France-Hawaii Telescope Multi-Color Microlensing Survey (K2C9-CFHT MCMS)
in order to measure the colors of microlensing source stars to improve the
accuracy of K2C9's parallax measurements. We describe the difference imaging
photometry analysis of the K2C9-CFHT MCMS observations, and present the
project's first data release. This includes instrumental difference flux
lightcurves of 217 microlensing events identified by other microlensing
surveys, reference image photometry calibrated to PanSTARRS data release 1
photometry, and tools to convert between instrumental and calibrated flux
scales. We derive accurate analytic transformations between the PanSTARRS
bandpasses and the Kepler bandpass, as well as angular diameter-color relations
in the PanSTARRS bandpasses. To demonstrate the use of our data set, we analyze
ground-based and K2 data of a short timescale microlensing event,
OGLE-2016-BLG-0795. We find the event has a timescale ~days and microlens parallax or , subject to the standard satellite parallax degeneracy. We argue that the
smaller value of the parallax is more likely, which implies that the lens is
likely a stellar-mass object in the Galactic bulge as opposed to a
super-Jupiter mass object in the Galactic disk.Comment: Submitted to PAS
An Earth-Mass Planet In A Time Of Covid-19: Kmt-2020-Blg-0414Lb
We report the discovery of KMT-2020-BLG-0414Lb, with a planet-to-host mass ratio q (2) = 0.9-1.2 x 10(-5) = 3-4 circle plus at 1 sigma, which is the lowest mass-ratio microlensing planet to date. Together with two other recent discoveries (4 less than or similar to q/q (circle plus) less than or similar to 6), it fills out the previous empty sector at the bottom of the triangular (log s, log q) diagram, where s is the planet-host separation in units of the angular Einstein radius theta E. Hence, these discoveries call into question the existence, or at least the strength, of the break in the mass-ratio function that was previously suggested to account for the paucity of very low-q planets. Due to the extreme magnification of the event, A (max) similar to 1450 for the underlying single-lens event, its light curve revealed a second companion with q (3) similar to 0.05 and |log s (3)| similar to 1, i.e., a factor similar to 10 closer to or farther from the host in projection. The measurements of the microlens parallax pi (E) and the angular Einstein radius theta E allow estimates of the host, planet and second companion masses, (M (1), M (2), M (3)) similar to (0.3 M (circle dot), 1.0 M (circle plus), 17 M-J ), the planet and second companion projected separations, (a (perpendicular to,2), a (perpendicular to,3)) similar to (1.5, 0.15 or 15) au, and system distance D (L) similar to 1 kpc. The lens could account for most or all of the blended light (I similar to 19.3) and so can be studied immediately with high-resolution photometric and spectroscopic observations that can further clarify the nature of the system. The planet was found as part of a new program of high-cadence follow-up observations of high-magnification events. The detection of this planet, despite the considerable difficulties imposed by COVID-19 (two KMT sites and OGLE were shut down), illustrates the potential utility of this program
OGLE-2018-BLG-0532Lb: Cold Neptune With Possible Jovian Sibling
We report the discovery of the planet OGLE-2018-BLG-0532Lb, with very obvious
signatures in the light curve that lead to an estimate of the planet-host mass
ratio . Although there are
no obvious systematic residuals to this double-lens/single-source (2L1S) fit,
we find that can be significantly improved by adding either a third
lens (3L1S, ) or second source (2L2S, ) to
the lens-source geometry. After thorough investigation, we conclude that we
cannot decisively distinguish between these two scenarios and therefore focus
on the robustly-detected planet. However, given the possible presence of a
second planet, we investigate to what degree and with what probability such
additional planets may affect seemingly single-planet light curves. Our best
estimates for the properties of the lens star and the secure planet are: a host
mass , system distance kpc and planet mass
with projected separation au.
However, there is a relatively bright (and also relatively blue) star
projected within mas of the lens, and if future high-resolution images
show that this is coincident with the lens, then it is possible that it is the
lens, in which case, the lens would be both more massive and more distant than
the best-estimated values above.Comment: 48 pages, 9 figures, 7 table
Parallax of OGLE-2018-BLG-0596: A Low-mass-ratio Planet around an M-dwarf
We report the discovery of a microlensing planet
OGLE-2018-BLG-0596Lb, with preferred planet-host mass ratio . The planetary signal, which is characterized by a short "bump" on the rising side of the lensing light curve, was densely
covered by ground-based surveys. We find that the signal can be explained by a
bright source that fully envelops the planetary caustic, i.e., a "Hollywood"
geometry. Combined with the source proper motion measured from , the
satellite parallax measurement makes it possible to precisely
constrain the lens physical parameters. The preferred solution, in which the
planet perturbs the minor image due to lensing by the host, yields a
Uranus-mass planet with a mass of orbiting
a mid M-dwarf with a mass of . There is also
a second possible solution that is substantially disfavored but cannot be ruled
out, for which the planet perturbs the major image. The latter solution yields
and . By
combining the microlensing and data together with a Galactic model, we
find in either case that the lens lies on the near side of the Galactic bulge
at a distance . Future adaptive optics
observations may decisively resolve the major image/minor image degeneracy.Comment: 34 pages, 8 figures, Submitted to AAS journa
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