Results for "Edward W. Schwieterman"

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A limited habitable zone for complex lifeFeb 13 2019The habitable zone (HZ) is defined as the range of distances from a host star within which liquid water, a key requirement for life, may exist at a planet's surface. Substantially more CO2 than present in Earth's modern atmosphere is required to maintain ... More
Earth: Atmospheric Evolution of a Habitable PlanetMar 15 2018Our present-day atmosphere is often used as an analog for potentially habitable exoplanets, but Earth's atmosphere has changed dramatically throughout its 4.5 billion year history. For example, molecular oxygen is abundant in the atmosphere today but ... More
Atmospheric Seasonality as an Exoplanet BiosignatureJun 12 2018Current investigations of exoplanet biosignatures have focused on static evidence of life, such as the presence of biogenic gases like O2 or CH4. However, the expected diversity of terrestrial planet atmospheres and the likelihood of both false positives ... More
Is the Pale Blue Dot unique? Optimized photometric bands for identifying Earth-like exoplanetsDec 01 2015Jan 29 2016The next generation of ground and space-based telescopes will image habitable planets around nearby stars. A growing literature describes how to characterize such planets with spectroscopy, but less consideration has been given to the usefulness of planet ... More
Rethinking CO Antibiosignatures in the Search for Life Beyond the Solar SystemMar 18 2019Some atmospheric gases have been proposed as counter indicators to the presence of life on an exoplanet if remotely detectable at sufficient abundance (i.e., antibiosignatures), informing the search for biosignatures and potentially fingerprinting uninhabited ... More
Detecting Ocean Glint on Exoplanets Using Multiphase MappingJan 15 2019Rotational mapping and glint are two proposed methods to directly detect liquid water on the surface of habitable exoplanets. However, false positives for both methods may prevent the unambiguous detection of exoplanet oceans. We use simulations of Earth ... More
Identifying Planetary Biosignature Impostors: Spectral Features of CO and O4 Resulting from Abiotic O2/O3 ProductionFeb 17 2016O2 and O3 have been long considered the most robust individual biosignature gases in a planetary atmosphere, yet multiple mechanisms that may produce them in the absence of life have been described. However, these abiotic planetary mechanisms modify the ... More
The Importance of UV Capabilities for Identifying Inhabited Exoplanets with Next Generation Space TelescopesJan 09 2018The strongest remotely detectable signature of life on our planet today is the photosynthetically produced oxygen (O2) in our atmosphere. However, recent studies of Earth's geochemical proxy record suggest that for all but the last ~500 million years, ... More
The remote detectability of Earth's biosphere through time and the importance of UV capability for characterizing habitable exoplanetsMar 13 2019Thousands of planets beyond our solar system have been discovered to date, dozens of which are rocky in composition and are orbiting within the circumstellar habitable zone of their host star. The next frontier in life detection beyond our solar system ... More
The Habitability of Proxima Centauri b: II: Environmental States and Observational DiscriminantsAug 30 2016Proxima Centauri b provides an unprecedented opportunity to understand the evolution and nature of terrestrial planets orbiting M dwarfs. Although Proxima Cen b orbits within its star's habitable zone, multiple plausible evolutionary paths could have ... More
Exoplanet Biosignatures: Future DirectionsMay 23 2017Aug 08 2017Exoplanet science promises a continued rapid accumulation of new observations in the near future, energizing a drive to understand and interpret the forthcoming wealth of data to identify signs of life beyond our Solar System. The large statistics of ... More
Exoplanet Biosignatures: A Review of Remotely Detectable Signs of LifeMay 16 2017Jun 25 2018In the coming years and decades, advanced space- and ground-based observatories will allow an unprecedented opportunity to probe the atmospheres and surfaces of potentially habitable exoplanets for signatures of life. Life on Earth, through its gaseous ... More
Exoplanet Biosignatures: Understanding Oxygen as a Biosignature in the Context of Its EnvironmentMay 22 2017Here we review how environmental context can be used to interpret whether O2 is a biosignature in extrasolar planetary observations. This paper builds on the overview of current biosignature research discussed in Schwieterman et al. (2017), and provides ... More
Modeling pN2 through Geological Time: Implications for Planetary Climates and Atmospheric BiosignaturesDec 08 2016Nitrogen is a major nutrient for all life on Earth and could plausibly play a similar role in extraterrestrial biospheres. The major reservoir of nitrogen at Earth's surface is atmospheric N2, but recent studies have proposed that the size of this reservoir ... More
False negatives for remote life detection on ocean-bearing planets: Lessons from the early EarthFeb 03 2017Ocean-atmosphere chemistry on Earth has undergone dramatic evolutionary changes through its long history, with potentially significant ramifications for the emergence and long-term stability of atmospheric biosignatures. Though a great deal of work has ... More
Abiotic O$_{2}$ Levels on Planets around F, G, K, and M Stars: Possible False Positives for Life?Sep 25 2015In the search for life on Earth-like planets around other stars, the first (and likely only) information will come from the spectroscopic characterization of the planet's atmosphere. Of the countless number of chemical species terrestrial life produces, ... More
The Pale Orange Dot: The Spectrum and Habitability of Hazy Archean EarthOct 14 2016Recognizing whether a planet can support life is a primary goal of future exoplanet spectral characterization missions, but past research on habitability assessment has largely ignored the vastly different conditions that have existed in our planet's ... More
Pale Orange Dots: The Impact of Organic Haze on the Habitability and Detectability of Earthlike ExoplanetsFeb 09 2017Hazes are common in known planet atmospheres, and geochemical evidence suggests early Earth occasionally supported an organic haze with significant environmental and spectral consequences. The UV spectrum of the parent star drives organic haze formation ... More
A safety net for fast migrators: Interactions between gap-opening and sub-gap-opening bodies in a protoplanetary diskFeb 21 2005Young planets interact with their parent gas disks through tidal torques. An imbalance between inner and outer torques causes bodies of mass $\ga 0.1$ Earth masses to lose angular momentum and migrate inward rapidly relative to the disk; this is known ... More
Large scattering events and the formation of planetary systemsSep 16 2002In the nucleated instability picture of gas giant formation, the final stage is the rapid accretion of a massive gas envelope by a solid core, bringing about a tenfold or more increase in mass. This tends to trigger the scattering of any nearby bodies, ... More
Search for Baryons in the Radiative Penguin Decay b--> s gammaMay 05 2003We have searched for the baryon-containing radiative penguin decays B^- -> \Lambda p-bar \gamma and B^- -> \Sigma^0 p-bar \gamma, using a sample of 9.7 million BBbar events collected at the \Upsilon(4S) with the CLEO detector. We find no evidence for ... More
The Importance of 3D General Circulation Models for Characterizing the Climate and Habitability of Terrestrial Extrasolar PlanetsMar 12 2019While recently discovered exotic new planet-types have both challenged our imaginations and broadened our knowledge of planetary system workings, perhaps the most compelling objective of exoplanet science is to detect and characterize habitable and possibly ... More
Nonphotosynthetic Pigments as Potential BiosignaturesMay 18 2015Previous work on possible surface reflectance biosignatures for Earth-like planets has typically focused on analogues to spectral features produced by photosynthetic organisms on Earth, such as the vegetation red edge. Although oxygenic photosynthesis, ... More
Cosmological Bounds to the Magnetic Moment of Heavy Tau NeutrinosMar 12 1996The magnetic moment of tau neutrinos in the MeV mass range may be large enough to modify the cosmological freeze-out calculation and determine the tau-neutrino relic density. In this paper we revisit such a possibility. We calculate the evolution and ... More
Preheating and symmetry restoration in collisions of vacuum bubblesFeb 19 1996In first-order inflation a phase transition is completed by the collisions of expanding true-vacuum bubbles. If bubble collisions produce large numbers of soft scalar particles carrying quantum numbers associated with a spontaneously broken symmetry, ... More
A model of subjective supply-demand: the maximum Boltzmann/Shannon entropy solutionNov 13 2008We investigate activities that have different periods of duration. We define the profit intensity as a measure of this economic category. The profit intensity in a repeated trading has a unique property of attaining its maximum at a fixed point regardless ... More
The Astumian's ParadoxAug 27 2004We discuss some aspects of Astumian suggestions that combination of biased games (Parrondo's paradox) can explain performance of molecular motors. Unfortunately the model is flawed by explicit asymmetry overlooked by the author. In addition, we show that ... More
Kelly Criterion revisited: optimal betsJul 18 2006Kelly criterion, that maximizes the expectation value of the logarithm of wealth for bookmaker bets, gives an advantage over different class of strategies. We use projective symmetries for a explanation of this fact. Kelly's approach allows for an interesting ... More
The InterHourly-Variability (IHV) Index of Geomagnetic Activity and its Use in Deriving the Long-term Variation of Solar Wind SpeedJun 07 2007We describe the derivation of the InterHourly Variability (IHV) index of geomagnetic activity. The IHV-index for a geomagnetic element is mechanically derived from hourly values as the sum of the unsigned differences between adjacent hours over a seven-hour ... More
The relativistic velocity addition law optimizes a forecast gambler's profitSep 26 2007We extend the projective covariant bookmaker's bets model to the forecasting gamblers case. The probability of correctness of forecasts shifts probabilities of branching. The formula for the shift of probabilities leads to the velocity addition rule of ... More
Heliospheric Magnetic Field 1835-2009Feb 15 2010Mar 27 2010We use recently acquired geomagnetic archival data to extend our long-term reconstruction of the HMF strength. The 1835-2009 HMF series is based on an updated and substantiated IDV series from 1872-onwards and on Bartels' extension, by proxy, of his u-series ... More
Life Beyond the Solar System: Remotely Detectable BiosignaturesJan 20 2018For the first time in human history, we will soon be able to apply the scientific method to the question "Are We Alone?" The rapid advance of exoplanet discovery, planetary systems science, and telescope technology will soon allow scientists to search ... More
A Statistical Comparative Planetology Approach to Maximize the Scientific Return of Future Exoplanet Characterization EffortsMar 12 2019Provided that sufficient resources are deployed, we can look forward to an extraordinary future in which we will characterize potentially habitable planets. Until now, we have had to base interpretations of observations on habitability hypotheses that ... More
The Increasing Rotation Period of Comet 10P/Tempel 2Sep 15 2010We imaged comet 10P/Tempel 2 on 32 nights from 1999 April through 2000 March. R-band lightcurves were obtained on 11 of these nights from 1999 April through 1999 June, prior to both the onset of significant coma activity and perihelion. Phasing of the ... More
A Quarter-Century of Observations of Comet 10P/Tempel 2 at Lowell Observatory: Continued Spin-Down, Coma Morphology, Production Rates, and Numerical ModelingOct 03 2012We report on photometry and imaging of Comet 10P/Tempel 2 obtained at Lowell Observatory from 1983 through 2011. We measured a nucleus rotation period of 8.950 +/- 0.002 hr from 2010 September to 2011 January. This rotation period is longer than the period ... More
Detecting and Constraining N$_2$ Abundances in Planetary Atmospheres Using Collisional PairsJul 28 2015Characterizing the bulk atmosphere of a terrestrial planet is important for determining surface pressure and potential habitability. Molecular nitrogen (N$_2$) constitutes the largest fraction of Earth$'$s atmosphere and is likely to be a major constituent ... More
On the reheating stage after inflationJul 18 2003We point out that inflaton decay products acquire plasma masses during the reheating phase following inflation. The plasma masses may render inflaton decay kinematicaly forbidden, causing the temperature to remain frozen for a period at a plateau value. ... More
Lorentz invariance violation in top-down scenarios of ultrahigh energy cosmic ray creationJun 29 2003Jan 28 2004The violation of Lorentz invariance (LI) has been invoked in a number of ways to explain issues dealing with ultrahigh energy cosmic ray (UHECR) production and propagation. These treatments, however, have mostly been limited to examples in the proton-neutron ... More
Relating Spectral Indices to Tensor and Scalar Amplitudes in InflationMar 01 1994Mar 19 1994Within an expansion in slow-roll inflation parameters, we derive the complete second-order expressions relating the ratio of tensor to scalar density perturbations and the spectral index of the scalar spectrum. We find that ``corrections'' to previously ... More
GUT Baryogenesis after PreheatingJun 07 1996Oct 24 1996At the end of inflation the universe is frozen in a near zero-entropy state with energy density in a coherent scalar field and must be ``defrosted'' to produce the observed entropy and baryon number. We propose that the baryon asymmetry is generated by ... More
Representing Structural Information of Helical Charge Distributions in Cylindrical CoordinatesDec 20 1996Structural information in the local electric field produced by helical charge distributions, such as dissolved DNA, is revealed in a straightforward manner employing cylindrical coordinates. Comparison of structure factors derived in terms of cylindrical ... More
Phase groups and the origin of non-locality for qubitsMar 25 2010We describe a general framework in which we can precisely compare the structures of quantum-like theories which may initially be formulated in quite different mathematical terms. We then use this framework to compare two theories: quantum mechanics restricted ... More
Non-Gaussianity from Broken SymmetriesNov 07 2005Recently we studied inflation models in which the inflaton potential is characterized by an underlying approximate global symmetry. In the first work we pointed out that in such a model curvature perturbations are generated after the end of the slow-roll ... More
Parameter estimation by fixed point of function of information processing intensityMar 31 2014We present a new method of estimating the dispersion of a distribution which is based on the surprising property of a function that measures information processing intensity. It turns out that this function has a maximum at its fixed point. We use a fixed-point ... More
Vector Bundles over Elliptic FibrationsSep 26 1997This paper gives various methods for constructing vector bundles over elliptic curves and more generally over families of elliptic curves. We construct universal families over generalized elliptic curves via spectral cover methods and also by extensions, ... More
Schrödinger type equation for subjective identification of supply and demandDec 20 2018The present authors have put forward a quantum game theory based model of market prices movements. By using Fisher information, we present a construction of an equation of Schr\"{o}dinger type for probability distributions for relationship between demand ... More
Proper Motion of the Leo II Dwarf Galaxy Based On Hubble Space Telescope ImagingAug 09 2016This article reports a measurement of the proper motion of Leo II, a dwarf galaxy that is a likely satellite of the Milky Way, based on imaging with the Hubble Space Telescope and Wide Field Camera 3. The measurement uses compact background galaxies as ... More
Proper Motion of the Draco Dwarf Galaxy Based On Hubble Space Telescope ImagingJul 13 2014We have measured the proper motion of the Draco dwarf galaxy using images at two epochs with a time baseline of about two years taken with the Hubble Space Telescope and the Advanced Camera for Surveys. Wide Field Channel 1 and 2 provide two adjacent ... More
Cosmological background solutions and cosmological backreactionsJan 28 2009Nov 20 2009The cosmological backreaction proposal, which attempts to account for observations without a primary dark energy source in the stress-energy tensor, has been developed and discussed by means of different approaches. Here, we focus on the concept of cosmological ... More
Light-cone averages in a swiss-cheese universeOct 29 2007Dec 21 2007We analyze a toy swiss-cheese cosmological model to study the averaging problem. In our model, the cheese is the EdS model and the holes are constructed from a LTB solution. We study the propagation of photons in the swiss-cheese model, and find a phenomenological ... More
Light-cone observations and cosmological models: implications for inhomogeneous models mimicking dark energyNov 19 2009Cosmological observables are used to construct cosmological models. Since cosmological observations are limited to the light cone, a fixed number of observables (even measured to arbitrary accuracy) may not uniquely determine a cosmological model without ... More
Large-amplitude isothermal fluctuations and high-density dark-matter clumpsMar 07 1994Large-amplitude isothermal fluctuations in the dark matter energy density, parameterized by $\Phi\equiv\delta\rhodm/\rhodm$, are studied within the framework of a spherical collapse model. For $\Phi \ga 1$, a fluctuation collapses in the radiation-dominated ... More
Non-Linear Axion Dynamics and Formation of Cosmological Pseudo-SolitonsNov 15 1993The $(3+1)$-dimensional evolution of an inhomogeneous axion field configuration around the QCD epoch is studied numerically, including important non-linear effects due to the attractive self-interaction. It is found that axion perturbations on scales ... More
Planetary Migration and Eccentricity and Inclination Resonances in Extrasolar Planetary SystemsJul 28 2009The differential migration of two planets due to planet-disk interaction can result in capture into the 2:1 eccentricity-type mean-motion resonances. Both the sequence of 2:1 eccentricity resonances that the system is driven through by continued migration ... More
An Introduction To The Web-Based FormalismJun 12 2015Jun 22 2016This paper summarizes our rather lengthy paper, "Algebra of the Infrared: String Field Theoretic Structures in Massive ${\cal N}=(2,2)$ Field Theory In Two Dimensions," and is meant to be an informal, yet detailed, introduction and summary of that larger ... More
Robust Designs via Geometric ProgrammingAug 22 2018An approximate formulation of a robust geometric program (RGP) as a convex program is proposed. Interest in using geometric programs (GPs) to model complex engineering systems has been growing, and this has motivated explicitly modeling the uncertainties ... More
Detection of Ocean Glint and Ozone Absorption Using LCROSS Earth ObservationsMay 18 2014The Lunar CRater Observation and Sensing Satellite (LCROSS) observed the distant Earth on three occasions in 2009. These data span a range of phase angles, including a rare crescent phase view. For each epoch, the satellite acquired near-infrared and ... More
Variations in Abundance Enhancements in Impulsive Solar Energetic-Particle Events and Related CMEs and FlaresJul 29 2014We study event-to-event variations in the abundance enhancements of the elements He through Pb for Fe-rich impulsive solar energetic-particle (SEP) events, and their relationship with properties of associated coronal mass ejections (CMEs) and solar flares. ... More
Incomplete Nested DissectionMay 23 2018We present an asymptotically faster algorithm for solving linear systems in well-structured 3-dimensional truss stiffness matrices. These linear systems arise from linear elasticity problems, and can be viewed as extensions of graph Laplacians into higher ... More
The subpulse modulation properties of pulsars at 21 cmJul 12 2005We present the results of a systematic, unbiased search for subpulse modulation of 187 pulsars performed with the Westerbork Synthesis Radio Telescope (WSRT) in the Netherlands at an observing wavelength of 21 cm. Using new observations and archival WSRT ... More
Statistics of the drifting subpulse phenomenonMay 08 2006We present the statistical results of a systematic, unbiased search for subpulse modulation of 187 pulsars performed with the Westerbork Synthesis Radio Telescope (WSRT) in the Netherlands at an observing wavelength of 21 cm (Weltevrede et al. 2006). ... More
The Radionactive UniverseJun 17 2003Aug 04 2003In a large class of extra-dimensional models, a scalar degree of freedom known as the radion is long-lived, or even stable, on cosmological scales. In this paper we investigate the impact of radionactivity on the evolution of the universe. We demonstrate ... More
Exotic massive hadrons and ultra-high energy cosmic raysMay 11 1998Oct 02 1998We investigate the proposal that primary cosmic rays of energy above the Greisen-Zatsepin-Kuzmin cutoff are exotic massive strongly interacting particles (uhecrons). We study the properties of air showers produced by uhecrons and find that masses in excess ... More
WMAPping inflationary physicsMay 12 2003Aug 01 2003We extract parameters relevant for distinguishing among single-field inflation models from the Wilkinson Microwave Anisotropy Probe (WMAP) data set, and from a combination of the WMAP data and seven other Cosmic Microwave Background (CMB) experiments. ... More
The Velocity Dispersion Profile of the Remote Dwarf Spheroidal Galaxy Leo I: A Tidal Hit and Run?Aug 09 2007(abridged) We present kinematic results for a sample of 387 stars located near Leo I based on spectra obtained with the MMT's Hectochelle spectrograph near the MgI/Mgb lines. We estimate the mean velocity error of our sample to be 2.4 km/s, with a systematic ... More
Momentum-space engineering of gaseous Bose-Einstein condensatesSep 03 2010Nov 19 2010We show how the momentum distribution of gaseous Bose--Einstein condensates can be shaped by applying a sequence of standing-wave laser pulses. We present a theory, whose validity for was demonstrated in an earlier experiment [L.\ Deng, et al., \prl {\bf ... More
From mean-motion resonances to scattered planets: Producing the Solar System, eccentric exoplanets and Late Heavy BombardmentsJun 08 2007We show that interaction with a gas disk may produce young planetary systems with closely-spaced orbits, stabilized by mean-motion resonances between neighbors. On longer timescales, after the gas is gone, interaction with a remnant planetesimal disk ... More
Revisiting the Sunspot NumberJul 11 2014Our knowledge of the long-term evolution of solar activity and of its primary modulation, the 11-year cycle, largely depends on a single direct observational record: the visual sunspot counts that retrace the last 4 centuries, since the invention of the ... More
Extra dimensions present a new flatness problemAug 14 2000There is no known fundamental reason to demand as a cosmological initial condition that the bulk possess an SO(3,1) isometry. On the contrary, one expects bulk curvature terms that violate the SO(3,1) isometry at early epochs, leading to a violation of ... More
Production of massive particles during reheatingSep 18 1998What is commonly called the reheat temperature, $T_{RH}$, is not the maximum temperature obtained after inflation. The maximum temperature is, in fact, much larger than $T_{RH}$. As an application of this we consider the production of massive stable dark-matter ... More
On the relic abundance of light photinosMar 22 1997We solve the coupled Boltzmann equation for the system of light photinos interacting with pions and $R^0$'s (the gluon-gluino bound state) to determine the relic abundance of light photinos in the light gaugino scenario. Cosmology bounds the ratio r of ... More
Structure of the Draco Dwarf Spheroidal GalaxyJan 17 2002This article studies the structure of the Draco dwarf spheroidal galaxy with an emphasis on the question of whether the spatial distribution of its stars has been affected by the tidal interaction with the Milky Way, using R- and V-band CCD photometry ... More
Oligarchic growth of giant planetsMar 12 2003Runaway growth ends when the largest protoplanets dominate the dynamics of the planetesimal disk; the subsequent self-limiting accretion mode is referred to as ``oligarchic growth.'' Here, we begin by expanding on the existing analytic model of the oligarchic ... More
The Neutron Star Mass-Radius Relation and the Equation of State of Dense MatterMay 31 2012The equation of state (EOS) of dense matter has been a long-sought goal of nuclear physics. Equations of state generate unique mass versus radius (M-R) relations for neutron stars, the ultra-dense remnants of stellar evolution. In this work, we determine ... More
Type I X-ray Bursts at Low Accretion RatesNov 02 2006Nov 02 2006Neutron stars, with their strong surface gravity, have interestingly short timescales for the sedimentation of heavy elements. Recent observations of unstable thermonuclear burning (observed as X-ray bursts) on the surfaces of slowly accreting neutron ... More
Revealing Carrier-Envelope Phase through Frequency Mixing and Interference in Frequency Resolved Optical GatingJan 20 2015We demonstrate that full temporal characterisation of few-cycle electromagnetic pulses, including retrieval of the carrier envelope phase (CEP), can be directly obtained from Frequency Resolved Optical Gating (FROG) techniques in which the interference ... More
Error correcting codes for adiabatic quantum computationDec 20 2005Oct 10 2006Recently, there has been growing interest in using adiabatic quantum computation as an architecture for experimentally realizable quantum computers. One of the reasons for this is the idea that the energy gap should provide some inherent resistance to ... More
Modeling Thermal Fluctuations: Phase Mixing and PercolationDec 05 1995We consider the nonequilibrium dynamics of a a real scalar field in a degenerate double-well potential. The system is prepared in the lowest free energy state in one of the wells and the dynamics is driven by the coupling of the field to a thermal bath. ... More
The Growth & Migration of Jovian Planets in Evolving Protostellar Disks with Dead ZonesSep 22 2008The growth of Jovian mass planets during migration in their protoplanetary disks is one of the most important problems that needs to be solved in light of observations of the exosolar planets. Studies of the migration of planets in standard gas disk models ... More
Saving Planetary Systems: Dead Zones & Planetary MigrationJun 09 2006Jan 16 2007The tidal interaction between a disk and a planet leads to the planet's migration. A long-standing question regarding this mechanism is how to stop the migration before planets plunge into their central stars. In this paper, we propose a new, simple mechanism ... More
Inequalities for the overpartition functionAug 15 2018Aug 16 2018Let $\overline{p}(n)$ denote the overpartition funtion. Engel showed that for $n\geq2$, $\overline{p}(n)$ satisfied the Tur\'{a}n inequalities, that is, $\overline{p}(n)^2-\overline{p}(n-1)\overline{p}(n+1)>0$ for $n\geq2$. In this paper, we prove several ... More
Ribbons on the CBR Sky: A Powerful Test of a Baryon Symmetric UniverseApr 09 1997May 02 1997If the Universe consists of domains of matter and antimatter, annihilations at domain interfaces leave a distinctive imprint on the Cosmic Background Radiation (CBR) sky. The signature is anisotropies in the form of long, thin ribbons of width $\theta_W\sim ... More
Resonance Trapping in Protoplanetary Disks. I. Coplanar SystemsJan 12 2008Sep 23 2008Mean-motion resonances (MMRs) are likely to play an important role both during and after the lifetime of a protostellar gas disk. We study the dynamical evolution and stability of planetary systems containing two giant planets on circular orbits near ... More
High resolution cathodoluminescence hyperspectral imaging of surface features in InGaN/GaN multiple quantum well structuresFeb 09 2011Jul 18 2011InGaN/GaN multiple quantum wells (MQWs) have been studied by using cathodoluminescence hyperspectral imaging with high spatial resolution. Variations in peak emission energies and intensities across trench-like features and V-pits on the surface of the ... More
Mechanism of stimulated Hawking radiation in a laboratory Bose-Einstein condensateMay 03 2016Sep 07 2016We model a sonic black hole analog in a quasi one-dimensional Bose-Einstein condensate, using a Gross-Pitaevskii equation matching the configuration of a recent experiment by Steinhauer. The model agrees well with important features of the experimental ... More
Cosmic microwave background measurements can discriminate among inflation modelsFeb 19 1997Quantum fluctuations during inflation may be responsible for temperature anisotropies in the cosmic microwave background (CMB). Observations of CMB anisotropies can be used to falsify many currently popular models. In this paper we discuss the prospectus ... More
Stars of the Draco Dwarf Spheroidal Galaxy Beyond its Measured Tidal BoundaryNov 01 2000We report R- and V-band photometry derived from CCD imaging for objects in nine fields in and around the Draco dwarf spheroidal galaxy. The most distant fields are about 1.3 degrees from the center. We use these data to search for Draco stars outside ... More
Copula Modeling of Multivariate Longitudinal Data with DropoutOct 10 2018Feb 09 2019Joint multivariate longitudinal and time-to-event data are gaining increasing attention in the biomedical sciences where subjects are followed over time to monitor the progress of a disease or medical condition. In the insurance context, claims outcomes ... More
Protein multi-scale organization through graph partitioning and robustness analysis: Application to the myosin-myosin light chain interactionSep 20 2011Despite the recognized importance of the multi-scale spatio-temporal organization of proteins, most computational tools can only access a limited spectrum of time and spatial scales, thereby ignoring the effects on protein behavior of the intricate coupling ... More
Probing dark matter couplings to top and bottom at the LHCMar 26 2013Monojet searches are a powerful way to place model-independent constraints on effective operators coupling dark matter to the standard model. For operators generated by the exchange of a scalar mediator, however, couplings to light quarks are suppressed ... More
Exoplanet Science Priorities from the Perspective of Internal and Surface Processes for Silicate and Ice Dominated WorldsApr 13 2018The geophysics of extrasolar planets is a scientific topic often regarded as standing largely beyond the reach of near-term observations. This reality in no way diminishes the central role of geophysical phenomena in shaping planetary outcomes, from formation, ... More
Tunneling phase gate for neutral atoms in a double-well latticeDec 12 2007We propose a new two--qubit phase gate for ultra--cold atoms confined in an experimentally realized tilted double--well optical lattice [Sebby--Strabley et al., Phys. Rev. A {\bf 73} 033605 (2006)]. Such a lattice is capable of confining pairs of atoms ... More
Astrophysical False Positives Encountered in Wide-Field Transit SearchesJan 07 2004Wide-field photometric transit surveys for Jupiter-sized planets are inundated by astrophysical false positives, namely systems that contain an eclipsing binary and mimic the desired photometric signature. We discuss several examples of such false alarms. ... More
The genomic impacts of drift and selection for hybrid performance in maizeJul 27 2013Modern maize breeding relies upon selection in inbreeding populations to improve the performance of cross-population hybrids. The United States Department of Agriculture - Agricultural Research Service reciprocal recurrent selection experiment between ... More
Consequence of superfluidity on the expansion of a rotating Bose-Einstein condensateJun 05 2001We study the time evolution of a rotating condensate, that expands after being suddenly released from the confining trap, by solving the hydrodynamic equations of irrotational superfluids. For slow initial rotation speeds, $\Omega_{0}$, we find that the ... More
Probing Planckian physics: resonant production of particles during inflation and features in the primordial power spectrumOct 21 1999The phenomenon of resonant production of particles {\it after} inflation has received much attention in the past few years. In a new application of resonant production of particles, we consider the effect of a resonance {\em during} inflation. We show ... More
Reconstructing the Inflaton Potential --- an OverviewAug 17 1995Oct 25 1996We review the relation between the inflationary potential and the spectra of density (scalar) perturbations and gravitational waves (tensor perturbations) produced, with particular emphasis on the possibility of reconstructing the inflaton potential from ... More
Reconstructing the Inflaton Potential---in Principle and in PracticeMar 22 1993Generalizing the original work by Hodges and Blumenthal, we outline a formalism which allows one, in principle, to reconstruct the potential of the inflaton field from knowledge of the tensor gravitational wave spectrum or the scalar density fluctuation ... More
Observing the Inflaton PotentialApr 07 1993We show how observations of the density perturbation (scalar) spectrum and the gravitational wave (tensor) spectrum allow a reconstruction of the potential responsible for cosmological inflation. A complete functional reconstruction or a perturbative ... More
The Michigan/MIKE Fiber System Survey of Stellar Radial Velocities in Dwarf Spheroidal Galaxies: Acquisition and Reduction of DataMar 12 2007Mar 14 2007We introduce a stellar velocity survey of dwarf spheroidal galaxies, undertaken using the Michigan/MIKE Fiber System (MMFS) at the Magellan/Clay 6.5 m telescope at Las Campanas Observatory. As of 2006 November we have used MMFS to collect 6415 high-resolution ... More