Results for "Yoon-Hyun Ryu"

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Microlensing by a wide-separation planet: detectability and boundnessJun 05 2013We explore the detection condition of a wide-separation planet through the perturbation induced by the planetary caustic for various microlensing parameters, especially for the size of the source stars. By constructing the fractional deviation maps at ... More
Microlensing Optical Depth Revisited with Recent Star CountsAug 19 2008More reliable constraints on the microlensing optical depth comes from a better understanding of the Galactic model. Based on well-constrained Galactic bulge and disk models constructed from survey observations, such as, HST, 2MASS, and SDSS, we calculate ... More
Gravitational Microlensing: A Tool for Detecting and Characterizing Free-Floating PlanetsNov 18 2003Various methods have been proposed to search for extrasolar planets. Compared to the other methods, microlensing has unique applicabilities to the detections of Earth-mass and free-floating planets. However, the microlensing method is seriously flawed ... More
Effective scalar four-fermion interaction for Ge-phobic exothermic dark matter and the CDMS-II Silicon excessOct 28 2014Feb 02 2015We discuss within the framework of effective four-fermion scalar interaction the phenomenology of a Weakly Interacting Massive Particle (WIMP) Dirac Dark Matter candidate which is exothermic (i.e. is metastable and interacts with nuclear targets down-scattering ... More
Two-Dimensional Axisymmetric Collapse of Thermally Unstable Primordial CloudsNov 08 2002We have performed two-dimensional hydrodynamic simulations of the collapse of isolated axisymmetric clouds condensing via radiative cooling in a primordial background gas. In order to study the development of the so-called ``shape-instability'', we have ... More
Efficient magneto-optical trapping of Yb atoms with a violet laser diodeSep 05 2003We report the first efficient trapping of rare-earth Yb atoms with a high-power violet laser diode (LD). An injection-locked violet LD with a 25 mW frequency-stabilized output was used for the magneto-optical trapping (MOT) of fermionic as well as bosonic ... More
Binary optimal linear codes from posets of the disjoint union of two chainsJun 28 2019Recently, Chang and Hyun obtained some classes of binary optimal codes via simplicial complexes. In this letter, we utilize posets of the disjoint union of two chains to construct binary optimal linear codes.
NASA ExoPAG Study Analysis Group 11: Preparing for the WFIRST Microlensing SurveySep 09 2014NASA's proposed WFIRST-AFTA mission will discover thousands of exoplanets with separations from the habitable zone out to unbound planets, using the technique of gravitational microlensing. The Study Analysis Group 11 of the NASA Exoplanet Program Analysis ... More
Properties of Central Caustics in Planetary MicrolensingMay 18 2005May 20 2005To maximize the number of planet detections, current microlensing follow-up observations are focusing on high-magnification events which have a higher chance of being perturbed by central caustics. In this paper, we investigate the properties of central ... More
Effects of Rotation on Thermal-Gravitational Instability in the Protogalactic Disk EnvironmentApr 26 2006Thermal-gravitational instability (TGI) is studied in the protogalactic environment. We extend our previous work, where we found that dense clumps first form out of hot background gas by thermal instability and later a small fraction of them grow to virialized ... More
Three-Dimensional Numerical Simulations of Thermal-Gravitational Instability in Protogalactic Halo EnvironmentJun 08 2005We study thermal-gravitational instability in simplified models for protogalactic halos using three-dimensional hydrodynamic simulations. The simulations followed the evolution of gas with radiative cooling down to T = 10^4 K, background heating, and ... More
Enhancing entanglement detection of quantum optical frequency combs via stimulated emissionFeb 12 2019Mar 26 2019We investigate the performance of a certain nonclassicality identifier, expressed via integrated second-order intensity moments of optical fields, in revealing bipartite entanglement of quantum-optical frequency combs (QOFCs), which are generated in both ... More
DAMA/LIBRA-phase2 in WIMP effective modelsApr 20 2018Jul 04 2018The DAMA/LIBRA collaboration has recently released updated results from their search for the annual modulation signal expected from Dark Matter (DM) scattering in their NaI detectors. We have fitted the updated DAMA result for the modulation amplitudes ... More
On the sensitivity of present direct detection experiments to WIMP-quark and WIMP-gluon effective interactions: a systematic assessment and new model-independent approachesOct 01 2018Aug 06 2019Assuming for Weakly Interacting Massive Particles (WIMPs) a Maxwellian velocity distribution in the Galaxy we provide an assessment of the sensitivity of existing Dark Matter (DM) direct detection (DD) experiments to operators up to dimension 7 of the ... More
Simple proofs for duality of generalized minimum poset weights and weight distributions of (Near-)MDS poset codesApr 06 2011In 1991, Wei introduced generalized minimum Hamming weights for linear codes and showed their monotonicity and duality. Recently, several authors extended these results to the case of generalized minimum poset weights by using different methods. Here, ... More
Theory of three-pulse photon echo spectroscopy with dual frequency combsMay 28 2019A theoretical analysis is carried out for the recently developed three-pulse photon echo spectroscopy employing dual frequency combs (DFC) as the light sources. In this method, the molecular sample interacts with three pulse trains derived from the DFC ... More
Laser induced birefringence in a wavelength-mismatched cascade system of inhomogeneously broadened Yb atomsNov 03 2004We report the observation of laser induced birefringence (LIB) in a wavelength-mismatched cascade system (J=0 \leftrightarrow J=1 \leftrightarrow J=0 transitions) of inhomogeneously broadened ytterbium atoms with strong pump and probe fields. We investigate ... More
3D Semantic Trajectory Reconstruction from 3D Pixel ContinuumDec 04 2017This paper presents a method to reconstruct dense semantic trajectory stream of human interactions in 3D from synchronized multiple videos. The interactions inherently introduce self-occlusion and illumination/appearance/shape changes, resulting in highly ... More
Fluorescence detection of single lithium atoms in an optical lattice using Doppler-cooling beamsMar 21 2017We demonstrate in situ fluorescence detection of $^7$Li atoms in a 1D optical lattice with single atom precision. Even though illuminated lithium atoms tend to boil out, when the lattice is deep, molasses beams without extra cooling retain the atoms while ... More
Effective models of WIMP Direct Detection in DAMA/LIBRA-phase2Oct 25 2018Since the DAMA/LIBRA collaboration released updated results from their search for the annual modulation signal expected from Dark Matter (DM) scattering in their NaI detectors, we have fitted the updated DAMA result for the modulation amplitudes for a ... More
Present and projected sensitivities of Dark Matter direct detection experiments to effective WIMP-nucleus couplingsMay 16 2018Feb 28 2019Assuming for Weakly Interacting Massive Particles (WIMPs) a Maxwellian velocity distribution in the Galaxy we explore in a systematic way the relative sensitivity of an extensive set of existing and projected Dark Matter (DM) direct detection experiments ... More
Properties of microlensing events by wide separation planets with a moonJun 02 2016We investigate the properties of microlensing events caused by planetary systems where planets with a moon are widely separated from their host stars. From this investigation, we find that the moon feature generally appears as an very short-duration perturbation ... More
Microlensing under ShearAug 18 2007We investigate the distortions due to this shear in the microlensing light curves and in the astrometric microlensing centroid shift trajectories. As expected, the light curve deviation increases as the shear increases and the impact parameter decreases. ... More
KMT-2016-BLG-1820 and KMT-2016-BLG-2142: Two Microlensing Binaries Composed of Planetary-mass Companions and Very-Low-Mass PrimariesMay 25 2018Sep 18 2018We present the analyses of two short-timescale $(t_{\rm E} \sim 5~{\rm days})$ microlensing events, KMT-2016-BLG-1820 and KMT-2016-BLG-2142. In both light curves, the brief anomalies were clearly captured and densely covered by the Korea Microlensing ... More
KMT-2016-BLG-1107: A New Hollywood-Planet Close/Wide DegeneracyMay 22 2018Nov 13 2018We show that microlensing event KMT-2016-BLG-1107 displays a new type of degeneracy between wide-binary and close-binary Hollywood events in which a giant-star source envelops the planetary caustic. The planetary anomaly takes the form of a smooth, two-day ... More
Kmt-2016-blg-1397b: Kmtnet-only discovery of a microlens giant planetOct 25 2018We report the discovery of a giant planet in the KMT-2016-BLG-1397 microlensing event, which was found by The Korea Microlensing Telescope Network (KMTNet) alone. The time scale of this event is t_E = 40.0 +- 0.5 days and the mass ratio between the lens ... More
KMT-2018-BLG-1990Lb: A Nearby Jovian Planet From A Low-Cadence Microlensing FieldMay 14 2019We report the discovery and characterization of KMT-2018-BLG-1990Lb, a Jovian planet $(m_p=0.57_{-0.25}^{+0.79}\,M_J)$ orbiting a late M dwarf $(M=0.14_{-0.06}^{+0.20}\,M_\odot)$, at a distance $(D_L=1.23_{-0.43}^{+1.06}\,\kpc)$, and projected at $2.6\pm ... More
The Korea Microlensing Telescope Network (KMTNet) Alert Algorithm and Alert SystemJun 20 2018We describe a new microlensing-event alert algorithm that is tailored to the Korea Microlensing Telescope Network (KMTNet) multi-observatory system. The algorithm focuses on detecting "rising" events, i.e., events whose brightness is increasing as a function ... More
Deep learning approach to coherent noise reduction in optical diffraction tomographyNov 16 2018We present a deep neural network to reduce coherent noise in three-dimensional quantitative phase imaging. Inspired by the cycle generative adversarial network, the denoising network was trained to learn a transform between two image domains: clean and ... More
Quasi-Scarred Resonances in a Spiral-Shaped MicrocavityMar 15 2004Sep 06 2004We study resonance patterns of a spiral-shaped dielectric microcavity with chaotic ray dynamics. Many resonance patterns of this microcavity, with refractive indices $n=2$ and 3, exhibit strong localization of simple geometric shape, and we call them ... More
Hadronic description for Omega baryon photoproductionJan 16 2014In the present work, we investigate subsequential production of three kaons and $\Omega^-$ baryon based on an effective Lagrangian approach. We only consider the intermediate states with the light mass baryon to suggest the minimum of the total cross ... More
Kaon condensation and composition of neutron star matter in modified quark-meson coupling modelJan 10 2006Mar 29 2007We use the modified quark-meson coupling (MQMC) model to study the composition profile of neutron star matter and compare the results with those calculated by quantum hadrodynamics (QHD). Both MQMC and QHD model parameters are adjusted to produce exactly ... More
Photoproduction of the scalar mesons $f_0(500)$ and $f_0(980)$ off the nucleonAug 04 2016Jul 19 2017We investigate photoproduction of the scalar mesona off the nucleon, using the effective Lagrangians and the Regge approach. We first study $f_0(980)$ photoproduction, replacing the Feynman propagator with the Regge ones for the $\rho$-meson exchange ... More
KMT-2016-BLG-2052L: Microlensing Binary Composed of M Dwarfs Revealed from a Very Long Time-scale EventJul 30 2018We present the analysis of a binary microlensing event KMT-2016-BLG-2052, for which the lensing-induced brightening of the source star lasted for 2 seasons. We determine the lens mass from the combined measurements of the microlens parallax $\pie$ and ... More
KMT-2018-BLG-0029Lb: A Very Low Mass-Ratio Spitzer Microlens PlanetJun 26 2019At $q=1.81\pm 0.20 \times 10^{-5}$, KMT-2018-BLG-0029Lb has the lowest planet-host mass ratio $q$ of any microlensing planet to date by more than a factor of two. Hence, it is the first planet that probes below the apparent "pile-up" at $q=5$--10 $\times ... More
Self-Supervised Adaptation of High-Fidelity Face Models for Monocular Performance TrackingJul 25 2019Improvements in data-capture and face modeling techniques have enabled us to create high-fidelity realistic face models. However, driving these realistic face models requires special input data, e.g. 3D meshes and unwrapped textures. Also, these face ... More
KMT-2017-BLG-0165Lb: A Super-Neptune mass planet Orbiting a Sun-like Host StarSep 05 2018Dec 27 2018We report the discovery of a low mass-ratio planet $(q = 1.3\times10^{-4})$, i.e., 2.5 times higher than the Neptune/Sun ratio. The planetary system was discovered from the analysis of the KMT-2017-BLG-0165 microlensing event, which has an obvious short-term ... More
KMT-2018-BLG-1292: A Super-Jovian Microlens Planet in the Galactic PlaneMay 13 2019We report the discovery of KMT-2018-BLG-1292Lb, a super-Jovian $M_{\rm planet} = 4.5\pm 1.3\,M_J$ planet orbiting an F or G dwarf $M_{\rm host} = 1.5\pm 0.4\,M_\odot$, which lies physically within ${\cal O}(10\,\pc)$ of the Galactic plane. The source ... More
Sharp conditions for the existence of an even $[a,b]$-factor in a graphSep 14 2018Let $a$ and $b$ be positive integers. An even $[a,b]$-factor of a graph $G$ is a spanning subgraph $H$ such that for every vertex $v \in V(G)$, $d_H(v)$ is even and $a \le d_H(v) \le b$. Matsuda conjectured that if $G$ is an $n$-vertex 2-edge-connected ... More
Horizontal-Branch Stars as an Age IndicatorJun 18 1999Surface temperature distribution of horizontal-branch (HB) stars is very sensitive to age in old stellar systems, which makes it an attractive age indicator. In this paper, we present the recent revision of our model calculations for the HB morphology ... More
Evolutionary models of red supergiants: Evidence for a metallicity-dependent mixing length and implications for Type IIP supernova progenitorsNov 09 2017Recent studies on the temperatures of red supergiants (RSGs) in the local universe provide us with an excellent observational constraint on RSG models. We calibrate the mixing length parameter by comparing model predictions with the empirical RSG temperatures ... More
Disjoint Multi-task Learning between Heterogeneous Human-centric TasksFeb 14 2018Human behavior understanding is arguably one of the most important mid-level components in artificial intelligence. In order to efficiently make use of data, multi-task learning has been studied in diverse computer vision tasks including human behavior ... More
Phosphorus in the Young Supernova Remnant Cassiopeia ADec 13 2013Phosphorus ($^{31}$P), which is essential for life, is thought to be synthesized in massive stars and dispersed into interstellar space when these stars explode as supernovae (SNe). Here we report on near-infrared spectroscopic observations of the young ... More
Comment on "Quasi-One-Dimensional Metal-Insulator Transitions in Compound Semiconductor Surfaces"Nov 25 2016May 10 2017In a recent Letter, Zhao et al. [1] reported the origin of quasi-one-dimensional metal-insulator (MI) transitions in compound semiconductor surfaces. Based on a density-functional theory (DFT) calculation within the generalized gradient approximation ... More
HUMBI 1.0: HUman Multiview Behavioral Imaging DatasetDec 01 2018This paper presents a new dataset called HUMBI - a large corpus of high fidelity models of behavioral signals in 3D from a diverse population measured by a massive multi-camera system. With our novel design of a portable imaging system (consists of 107 ... More
Bipolar resistive switching characteristics of poly(3,4-ethylene-dioxythiophene): poly(styrenesulfonate) thin filmAug 25 2009We investigated the reversible resistive switching of poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) thin films sandwiched between Al electrodes. The J-V sweep curve showed a hysteretic behavior which depends on the polarity of the ... More
Detection Probability of a Low-Mass Planet for Triple Lens Events: Implication of Properties of Binary-Lens SuperpositionOct 27 2010In view of the assumption that any planetary system is likely to be composed of more than one planet, and the multiple planet system with a large mass planet has more chance of detailed follow-up observations, the multiple planet system may be an efficient ... More
Correlations Between Planetary Microlensing ParametersSep 02 2010Characterization of microlensing planets requires modeling of observed light curves including many parameters. Studying the dependency of the pattern of light curves on the lensing parameters and the correlations between the parameters is important to ... More
Energy-Based Sequence GANs for Recommendation and Their Connection to Imitation LearningJun 28 2017Recommender systems aim to find an accurate and efficient mapping from historic data of user-preferred items to a new item that is to be liked by a user. Towards this goal, energy-based sequence generative adversarial nets (EB-SeqGANs) are adopted for ... More
Deep learning-enabled image quality control in tomographic reconstruction: Robust optical diffraction tomographyMar 05 2019In tomographic reconstruction, the image quality of the reconstructed images can be significantly degraded by defects in the measured two-dimensional (2D) raw image data. Despite the importance of screening defective 2D images for robust tomographic reconstruction, ... More
Direct Band Gap Semiconducting Holey Graphyne: Structure, Synthesis and Potential ApplicationsJul 08 2019Here we report two-dimensional (2D) single-crystalline holey-graphyne (HGY) created an interfacial two-solvent system through a Castro-Stephens coupling reaction from 1,3,5-tribromo-2,4,6-triethynylbenzene. HGY is a new type of 2D carbon allotrope whose ... More
GPS Receiver with Enhanced User Positioning TimeOct 11 2015This paper introduces a Global Positioning System (GPS) Receiver that locates user's position instantly. Recently, many mobile devices require location information to add user position into their contents, and some applications require quick positioning ... More
End-to-end losses based on speaker basis vectors and all-speaker hard negative mining for speaker verificationFeb 07 2019Jul 17 2019In recent years, speaker verification has primarily performed using deep neural networks that are trained to output embeddings from input features such as spectrograms or Mel-filterbank energies. Studies that design various loss functions, including metric ... More
Mechanical force involved multiple fields switching of both local ferroelectric and magnetic domain in a Bi5Ti3FeO15 thin filmSep 26 2016Multiferroics have received intense attention due to their great application potential in multi-state information storage devices and new types of sensors. Coupling among ferroic orders such as ferroelectricity, (anti-)ferromagnetism, ferroelasticity, ... More
Intraoperative margin assessment of human breast tissue in optical coherence tomography images using deep neural networksMar 31 2017Objective: In this work, we perform margin assessment of human breast tissue from optical coherence tomography (OCT) images using deep neural networks (DNNs). This work simulates an intraoperative setting for breast cancer lumpectomy. Methods: To train ... More
A Planetary Microlensing Event with an Unusually Red Source Star: MOA-2011-BLG-291Jun 15 2018We present the analysis of planetary microlensing event MOA-2011-BLG-291, which has a mass ratio of $q=(3.8\pm0.7)\times10^{-4}$ and a source star that is redder (or brighter) than the bulge main sequence. This event is located at a low Galactic latitude ... More
Anomalous spin-orbit torque switching due to field-like torque-assisted domain wall reflectionNov 15 2017Spin-orbit torques (SOT) allow the electrical control of magnetic states. Current-induced SOT switching of the perpendicular magnetization is of particular technological importance. The SOT consists of damping-like and field-like torques so that the efficient ... More
OGLE-2018-BLG-0532Lb: Cold Neptune With Possible Jovian SiblingMay 15 2019We 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 $q=M_{\rm planet}/M_{\rm host}\simeq 1\times10^{-4}$. Although there are no obvious systematic ... More
MOA-2016-BLG-319Lb: Microlensing Planet Subject to Rare Minor-Image Perturbation Degeneracy in Determining Planet ParameterSep 21 2018We present the analysis of the planetary microlensing event MOA-2016-BLG-319. The event light curve is characterized by a brief ($\sim 3$ days) anomaly near the peak produced by minor-image perturbations. From modeling, we find two distinct solutions ... More
Optical properties of iron-based superconductor LiFeAs single crystalJan 04 2013Jul 01 2013We have measured the reflectivity spectra of the iron based superconductor LiFeAs (Tc = 17.6 K) in the temperature range from 4 to 300 K. In the superconducting state (T < Tc), the clear opening of the optical absorption gap was observed below 25 cm-1, ... More
The Limited Impact of Outflows: Integral-Field Spectroscopy of 20 Local AGNsFeb 07 2017To investigate AGN outflows as a tracer of AGN feedback on star-formation, we perform integral-field spectroscopy of 20 type 2 AGNs at z<0.1, which are luminous AGNs with the [O III] luminosity >10$^{41.5}$ erg/s, and exhibit strong outflow signatures ... More
SPEAR Far Ultraviolet Spectral Images of the Cygnus LoopJan 26 2006We present far-ultraviolet (FUV) spectral images, measured at C IV 1550, He II 1640, Si IV+O IV] 1400, and O III] 1664, of the entire Cygnus Loop, observed with the Spectroscopy of Plasma Evolution from Astrophysical Radiation (SPEAR) instrument, also ... More
Interplay of Inhomogeneous Electrochemical Reactions with Mechanical Responses in Silicon-Graphite Anode and its Impacts on DegradationJan 06 2019Jun 10 2019Enhanced EV market penetration requires durability of the battery with high energy throughput. For long-term cycle stability of silicon-graphite anode capable of high energy density, the reversible redox reactions are crucial. Here, we unveil intriguing ... More
Far-Ultraviolet Cooling Features of the Antlia Supernova RemnantOct 08 2007Oct 09 2007We present far-ultraviolet observations of the Antlia supernova remnant obtained with Far-ultraviolet IMaging Spectrograph (FIMS, also called SPEAR). The strongest lines observed are C IV 1548,1551 and C III 977. The C IV emission of this mixed-morphology ... More
A Planetary lensing feature in caustic-crossing high-magnification microlensing eventsMar 19 2012Current microlensing follow-up observations focus on high-magnification events because of the high efficiency of planet detection. However, central perturbations of high-magnification events caused by a planet can also be produced by a very close or a ... More
A New Application of the Astrometric Method to Break Severe Degeneracies in Binary Microlensing EventsJan 28 2009Jan 29 2009When a source star is microlensed by one stellar component of a widely separated binary stellar components, after finishing the lensing event, the event induced by the other binary star can be additionally detected. In this paper, we investigate whether ... More
Efficient Hybrid White Organic Light-Emitting Diodes for Application of Triplet Harvesting with Simple StructureMay 23 2016In this study, we fabricated hybrid white organic light-emitting diodes (WOLEDs) based on triplet harvesting with simple structure. All the hole transporting material and host in emitting layer (EML) of devices were utilized with same material by using ... More
Comb-rooted multi-channel synthesis of ultra-narrow optical frequencies of few Hz linewidthMar 26 2019We report a multi-channel optical frequency synthesizer developed to generate extremely stable continuous wave lasers directly out of the optical comb of an Er-doped fiber oscillator. Being stabilized to a high-finesse cavity with a fractional frequency ... More
An atomic array optical clock with single-atom readoutAug 15 2019Measuring time is central to all sciences. Currently, the most accurate and stable clocks are based on optical interrogation of either a single ion or an ensemble of neutral atoms confined in an optical lattice. Here we demonstrate a new optical clock ... More
Oscillatory spin-orbit torque switching induced by field-like torquesNov 15 2017Deterministic magnetization switching using spin-orbit torque (SOT) has recently emerged as an efficient means to electrically control the magnetic state of ultrathin magnets. The SOT switching still lacks in oscillatory switching characteristics over ... More
VPGNet: Vanishing Point Guided Network for Lane and Road Marking Detection and RecognitionOct 17 2017In this paper, we propose a unified end-to-end trainable multi-task network that jointly handles lane and road marking detection and recognition that is guided by a vanishing point under adverse weather conditions. We tackle rainy and low illumination ... More
OGLE-2015-BLG-1670Lb: A Cold Neptune beyond the Snow Line in the Provisional WFIRST Microlensing Survey FieldSep 28 2018Jun 24 2019We present the analysis of the microlensing event OGLE-2015-BLG-1670, detected in a high-extinction field, very close to the Galactic plane. Due to the dust extinction along the line of sight, this event was too faint to be detected before it reached ... More
OGLE-2016-BLG-0156: Microlensing Event With Pronounced Microlens-Parallax Effects Yielding Precise Lens Mass MeasurementJan 19 2019We analyze the gravitational binary-lensing event OGLE-2016-BLG-0156, for which the lensing light curve displays pronounced deviations induced by microlens-parallax effects. The light curve exhibits 3 distinctive widely-separated peaks and we find that ... More
OGLE-2018-BLG-0022: First Prediction of an Astrometric Microlensing Signal from a Photometric Microlensing EventMar 30 2019Apr 04 2019In this work, we present the analysis of the binary microlensing event OGLE-2018-BLG-0022 that is detected toward the Galactic bulge field. The dense and continuous coverage with the high-quality photometry data from ground-based observations combined ... More
Spitzer Microlensing of MOA-2016-BLG-231L : A Counter-Rotating Brown Dwarf Binary in the Galactic DiskFeb 08 2019Feb 12 2019We analyze the binary microlensing event MOA-2016-BLG-231, which was observed from the ground and from Spitzer. The lens is composed of very low-mass brown dwarfs (BDs) with $M_1 = 21^{+12}_{-5} \ M_J$ and $M_2 = 9^{+5}_{-2}\ M_J$, and it is located in ... More
$Spitzer$ Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-Rotating Low-Mass Brown DwarfMay 22 2018Jan 18 2019The kinematics of isolated brown dwarfs in the Galaxy, beyond the solar neighborhood, is virtually unknown. Microlensing has the potential to probe this hidden population, as it can measure both the mass and five of the six phase-space coordinates (all ... More
Spectroscopic Mass and Host-star Metallicity Measurements for Newly Discovered Microlensing Planet OGLE-2018-BLG-0740LbMay 01 2019Jul 03 2019We report the discovery of the microlensing planet OGLE-2018-BLG-0740Lb. The planet is detected with a very strong signal of $\Delta\chi^2\sim 4630$, but the interpretation of the signal suffers from two types of degeneracies. One type is caused by the ... More
$Spitzer$ Parallax of OGLE-2018-BLG-0596: A Low-mass-ratio Planet around an M-dwarfMay 14 2019We report the discovery of a $Spitzer$ microlensing planet OGLE-2018-BLG-0596Lb, with preferred planet-host mass ratio $q \sim 2\times10^{-4}$. The planetary signal, which is characterized by a short $(\sim 1~{\rm day})$ "bump" on the rising side of the ... More
Exactly solvable potentials with finitely many discrete eigenvalues of arbitrary choiceFeb 22 2014We address the problem of possible deformations of exactly solvable potentials having finitely many discrete eigenvalues of arbitrary choice. As Kay and Moses showed in 1956, reflectionless potentials in one dimensional quantum mechanics are exactly solvable. ... More
Symmetric Morse potential is exactly solvableNov 18 2016Morse potential $V_M(x)= g^2\exp (2x)-g(2h+1)\exp(x)$ is defined on the full line, $-\infty<x<\infty$ and it defines an exactly solvable 1-d quantum mechanical system with finitely many discrete eigenstates. By taking its right half $0\le x<\infty$ and ... More
Exactly and quasi-exactly solvable `discrete' quantum mechanicsApr 27 2010Brief introduction to the discrete quantum mechanics is given together with the main results on various exactly solvable systems. Namely, the intertwining relations, shape invariance, Heisenberg operator solutions, annihilation/creation operators, dynamical ... More
Quasi Exactly Solvable Difference EquationsAug 06 2007Oct 11 2007Several explicit examples of quasi exactly solvable `discrete' quantum mechanical Hamiltonians are derived by deforming the well-known exactly solvable Hamiltonians of one degree of freedom. These are difference analogues of the well-known quasi exactly ... More
Williams' Decomposition Theorem, Shift-Flip Equivalence, and the Lind Zeta functions for Shift-Flip Systems of Finite TypeJul 15 2014Shift-flip systems of finite type can be represented by a pair of zero-one square matrices, which is called a flip pair. The concepts of half elementary equivalence, strong shift-flip equivalence, and shift-flip equivalence between flip pairs are introduced. ... More
Confining non-analytic exponential potential $V(x)= g^2\exp\,(2|x|)$ and its exact Bessel-function solvabilityNov 08 2016In a previous paper we have shown that Schr\"{o}dinger equation with the non-analytic attractive exponential potential $V(x)= -g^2\exp (-|x|)$ is exactly solvable. It has finitely many discrete eigenstates described by the Bessel function of the first ... More
Stable systolic category of the product of spheresJul 17 2010The stable systolic category of a closed manifold M indicates the complexity in the sense of volume. This is a homotopy invariant, even though it is defined by some relations between homological volumes on M. We show an equality of the stable systolic ... More
Exactly Solvable Birth and Death ProcessesMar 18 2009Many examples of exactly solvable birth and death processes, a typical stationary Markov chain, are presented together with the explicit expressions of the transition probabilities. They are derived by similarity transforming exactly solvable `matrix' ... More
New Quasi Exactly Solvable Difference EquationDec 17 2007Exact solvability of two typical examples of the discrete quantum mechanics, i.e. the dynamics of the Meixner-Pollaczek and the continuous Hahn polynomials with full parameters, is newly demonstrated both at the Schroedinger and Heisenberg picture levels. ... More
Theoretical Modeling of ME effect at Low frequency and Resonance Frequency for Magnetoelectric Laminates with Anisotropic Piezoelectric PropertiesNov 29 2012Dec 09 2012A new theory is developed for the magnetoelectric (ME) coupling in a symmetric 2-2 ME laminate having a representative piezoelectric crystal (PMN-PT) particularly with anisotropic piezoelectric properties. Considering the average field method, the theoretical ... More
The volume and Chern-Simons invariant of a Dehn-filled manifoldJan 25 2018Feb 16 2019For a compact 3-manifold $N$ with non-empty boundary, Zickert gave a combinatorial formula for computing the volume and Chern-Simons invariant of a boundary parabolic representation $\pi_1(N)\rightarrow \mathrm{PSL}(2,\mathbb{C})$. In this paper, we introduce ... More
On the potential functions for a link diagramOct 22 2018For an oriented diagram of a link $L$ in the 3-sphere, Cho and Murakami defined the potential function whose critical point, slightly different from the usual sense, corresponds to a boundary parabolic $\mathrm{PSL}(2,\mathbb{C})$-representation of $\pi_1(S^3 ... More
Rotational properties of Maria asteroid familyNov 21 2013Maria family is regarded as an old-type (~3 +/- 1 Gyr) asteroid family which has experienced substantial collisional and dynamical evolution in the Main-belt. It is located nearby the 3:1 Jupter mean motion resonance area that supplies Near-Earth asteroids ... More
Absolute frequency measurement of 1S0 (F = 1/2) - 3P0 (F = 1/2) transition of 171Yb atoms in a one-dimensional optical lattice at KRISSDec 27 2011Jan 25 2013We measured the absolute frequency of the optical clock transition 1S0 (F = 1/2) - 3P0 (F = 1/2) of 171Yb atoms confined in a one-dimensional optical lattice and it was determined to be 518 295 836 590 863.5(8.1) Hz. The frequency was measured against ... More
Magnetic Domain-Wall Tilting due to Domain-Wall Speed AsymmetryApr 27 2017Jun 26 2017Chiral magnetic materials provide a number of challenging issues such as the highly efficient domain wall (DW) and skyrmion motions driven by electric current, as of the operation principles of emerging spintronic devices. The DWs in the chiral materials ... More
Search for an exotic light particle at BelleJun 05 2010Jun 11 2010The HyperCP experiment reported the observation of three events for the $\Sigma^+ \rightarrow p \mu^+\mu^-$ decay. The dimuon masses of the observed events are clustered within the detector resolution of 1 MeV/$c^2$. These decays might be interpreted ... More
Discovery of a Supercluster at $z\sim$0.91 and Testing the $Λ$CDM Cosmological ModelApr 12 2016The $\Lambda$CDM cosmological model successfully reproduces many aspects of the galaxy and structure formation of the universe. However, the growth of large-scale structures (LSSs) in the early universe is not well tested yet with observational data. ... More
The Background Geometry of DLCQ SupergravityFeb 05 1998Apr 15 1998By following Seiberg's prescriptions on DLCQ of $M$ theory, we give the background geometries of DLCQ supergravity associated with $N$ sector of DLCQ of $M$ theory on $T^p$ with vanishingly small radii. Most of these are the product of anti-de Sitter ... More
The Infrared Medium-deep Survey. IV. Low Eddington Ratio of A Faint Quasar at $z\sim6$: Not Every Supermassive Black Hole is Growing Fast in the Early UniverseFeb 08 2018To date, most of the luminous quasars known at $z\sim6$ have been found to be in maximal accretion with the Eddington ratios, $\lambda_{\rm{Edd}}\sim1$, suggesting enhanced nuclear activities in the early universe. However, this may not be the whole picture ... More
Oxygen Partial Pressure during Pulsed Laser Deposition: Deterministic Role on Thermodynamic Stability of Atomic Termination Sequence at SrRuO3/BaTiO3 InterfaceAug 10 2017With recent trends on miniaturizing oxide-based devices, the need for atomic-scale control of surface/interface structures by pulsed laser deposition (PLD) has increased. In particular, realizing uniform atomic termination at the surface/interface is ... More
The Infrared Medium-deep Survey. III. Survey of Luminous Quasars at 4.7 $\leq$ z $\leq$ 5.4Jun 26 2017We present our first results of the survey for high redshift quasars at $5 \lesssim {\rm z} \lesssim 5.7$. The search for quasars in this redshift range has been known to be challenging due to limitations of filter sets used in previous studies. We conducted ... More
Discovery of A Faint Quasar at z~6 and Implications for Cosmic ReionizationNov 05 2015Recent studies suggest that faint active galactic nuclei may be responsible for the reionization of the universe. Confirmation of this scenario requires spectroscopic identification of faint quasars ($M_{1450}>-24$ mag) at $z \gtrsim6$, but only a very ... More