S. Chatterjee - Cornell Uni

S. Chatterjee
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Name
S. Chatterjee
Affiliation
Cornell Uni
City
Irvine
Country
United States

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High Energy Astrophysical Phenomena (11)
 
Cosmology and Nongalactic Astrophysics (6)
 
Physics - Materials Science (6)
 
Instrumentation and Methods for Astrophysics (5)
 
Astrophysics of Galaxies (4)
 
Solar and Stellar Astrophysics (4)
 
Physics - Biological Physics (3)
 
General Relativity and Quantum Cosmology (3)
 
Computer Science - Human-Computer Interaction (3)
 
Physics - Chemical Physics (3)
 
High Energy Physics - Phenomenology (3)
 
Quantum Physics (3)
 
High Energy Physics - Theory (3)
 
Physics - Strongly Correlated Electrons (2)
 
Computer Science - Computer Vision and Pattern Recognition (2)
 
Statistics - Applications (2)
 
Mathematics - Information Theory (1)
 
Physics - Statistical Mechanics (1)
 
Quantitative Biology - Molecular Networks (1)
 
Nuclear Theory (1)
 
Quantitative Biology - Subcellular Processes (1)
 
Computer Science - Information Theory (1)
 
Statistics - Methodology (1)
 
Quantitative Biology - Quantitative Methods (1)
 
High Energy Physics - Experiment (1)
 
Statistics - Theory (1)
 
Mathematics - Probability (1)
 
Mathematical Physics (1)
 
Mathematics - Statistics (1)
 
Mathematics - Mathematical Physics (1)
 
Statistics - Machine Learning (1)

Publications Authored By S. Chatterjee

Plasma lenses in the host galaxies of fast radio bursts (FRBs) can strongly modulate FRB amplitudes for a wide range of distances, including the $\sim $ Gpc distance of the repeater FRB121102. To produce caustics, the lens' dispersion-measure depth (${\rm DM}_{\ell}$), scale size ($a$), and distance from the source ($d_{\rm sl}$) must satisfy ${\rm DM}_{\ell} d_{\rm sl} / a^2 \gtrsim 0.65~ {\rm pc^2 \ AU^{-2} \ cm^{-3}}$. Read More

2017Mar
Affiliations: 1ALMA Time-domain Special Interest Group, 2ALMA Time-domain Special Interest Group, 3ALMA Time-domain Special Interest Group, 4ALMA Time-domain Special Interest Group, 5ALMA Time-domain Special Interest Group, 6ALMA Time-domain Special Interest Group, 7ALMA Time-domain Special Interest Group, 8ALMA Time-domain Special Interest Group, 9ALMA Time-domain Special Interest Group, 10ALMA Time-domain Special Interest Group, 11ALMA Time-domain Special Interest Group, 12ALMA Time-domain Special Interest Group, 13ALMA Time-domain Special Interest Group, 14ALMA Time-domain Special Interest Group, 15ALMA Time-domain Special Interest Group, 16ALMA Time-domain Special Interest Group, 17ALMA Time-domain Special Interest Group, 18ALMA Time-domain Special Interest Group, 19ALMA Time-domain Special Interest Group, 20ALMA Time-domain Special Interest Group, 21ALMA Time-domain Special Interest Group, 22ALMA Time-domain Special Interest Group, 23ALMA Time-domain Special Interest Group, 24ALMA Time-domain Special Interest Group, 25ALMA Time-domain Special Interest Group, 26ALMA Time-domain Special Interest Group, 27ALMA Time-domain Special Interest Group, 28ALMA Time-domain Special Interest Group, 29ALMA Time-domain Special Interest Group, 30ALMA Time-domain Special Interest Group, 31ALMA Time-domain Special Interest Group, 32ALMA Time-domain Special Interest Group, 33ALMA Time-domain Special Interest Group, 34ALMA Time-domain Special Interest Group, 35ALMA Time-domain Special Interest Group, 36ALMA Time-domain Special Interest Group, 37ALMA Time-domain Special Interest Group

While the Atacama Large Millimeter/submillimeter Array (ALMA) is a uniquely powerful telescope, its impact in certain fields of astrophysics has been limited by observatory policies rather than the telescope's innate technical capabilities. In particular, several observatory policies present challenges for observations of variable, mobile, and/or transient sources --- collectively referred to here as "time-domain" observations. In this whitepaper we identify some of these policies, describe the scientific applications they impair, and suggest changes that would increase ALMA's science impact in Cycle 6 and beyond. Read More

The coordinate-space wave function $\psi(x)$ of quasi-one-dimensional atoms is defined in the $x\geq 0$ region only. This poses a typical problem to write a physically acceptable momentum-space wave function $\phi(p)$ from the Fourier transform of $\psi(x)$. We resolve the problem with special attention to the behavior of real and imaginary parts of the complex-valued function $\phi(p)$ as a function of $p$ and confirm that $\phi_i(p)$ (the imaginary part of $\phi(p)$) represents the correct momentum-space wave function. Read More

We make use of a Hylleraas-type wave function to derive an exact analytical model to quantify correlation in two-electron atomic/ionic systems and subsequently employ it to examine the role of inter-electronic repulsion in affecting (i) the bare (uncorrelated) single-particle position- and momentum-space charge distributions and (ii) corresponding Shannon's information entropies. The results presented for the first five members in the helium iso-electronic sequence, on the one hand, correctly demonstrate the effect of correlation on bare charge distributions and, on the other hand, lead us to some important results for the correlated and uncorrelated values of the entropies. These include the limiting behavior of the correlated entropy sum (sum of position- and momentum-space entropies) and geometrical realization for the variation of information entropies as a function of Z. Read More

Taking into account the current global information on neutrino oscillation parameters we forecast the capabilities of future long baseline experiments such as DUNE and T2HK in settling the atmospheric octant puzzle. We find that a good measurement of the reactor angle $\theta_{13}$ plays a key role in fixing the octant of the atmospheric angle $\theta_{23}$ with such future accelerator neutrino studies. Read More

The upcoming Ooty Wide Field Array (OWFA) will operate at $326.5 \, {\rm MHz}$ which corresponds to the redshifted 21-cm signal from neutral hydrogen (HI) at z = 3.35. Read More

Several analytic and numerical studies have indicated that the interstellar medium of a quasar host galaxy heated by feedback can contribute to a substantial secondary signal in the cosmic microwave background (CMB) through the thermal Sunyaev-Zel'dovich (SZ) effect. Recently, many groups have tried to detect this signal by cross-correlating CMB maps with quasar catalogs. Using a self-similar model for the gas in the intra-cluster medium and a realistic halo occupation distribution (HOD) prescription for quasars we estimate the level of SZ signal from gravitational heating of quasar hosts. Read More

Numerous experiments have reported discrete symmetry breaking in the high temperature pseudogap phase of the hole-doped cuprates, including breaking of one or more of lattice rotation, inversion, or time-reversal symmetries. In the absence of translational symmetry breaking or topological order, these conventional order parameters cannot explain the gap in the charged fermion excitation spectrum in the anti-nodal region. Zhao et al. Read More

The volume of data that will be produced by new-generation surveys requires automatic classification methods to select and analyze sources. Indeed, this is the case for the search for strong gravitational lenses, where the population of the detectable lensed sources is only a very small fraction of the full source population. In this paper, we present a morphological classification method for recognizing strong gravitational lenses. Read More

The poor contrast and the overlapping of cervical cell cytoplasm are the major issues in the accurate segmentation of cervical cell cytoplasm. This paper presents an automated unsupervised cytoplasm segmentation approach which can effectively find the cytoplasm boundaries in overlapping cells. The proposed approach first segments the cell clumps from the cervical smear image and detects the nuclei in each cell clump. Read More

We study trend filtering, a relatively recent method for univariate nonparametric regression. For a given integer $r \geq 1$, the trend filtering estimator of order $r$ is defined as the minimizer of the sum of squared errors when we constrain (or penalize) the sum of the absolute discrete derivatives of order $r$ over the input points. For $r = 1$, the estimator reduces to total variation regularization which has received much attention in the statistics and image processing literature. Read More

We perform realistic simulations of the current and future long baseline experiments such as T2K, NO$\nu$A, DUNE and T2HK in order to determine their ultimate potential in probing neutrino oscillation parameters. We quantify the potential of these experiments to underpin the octant of the atmospheric angle $\theta_{23}$ as well as the value and sign of the CP phase $\delta_{CP}$ Read More

In this work, we investigate the local and nonlocal broadcasting of entanglement and correlations in more general sense for the general two-qubit mixed state using asymmetric Pauli cloners. Interestingly, we claim that non-optimal broadcasting of entanglement is not different from optimal broadcasting using asymmetric cloners. Surprisingly, this is exactly opposite to the behaviour for geometric discord, a measure of correlation beyond entanglement. Read More

This study examines the presence of the day-of-the-week effect on daily returns of biotechnology stocks over a 16-year period from January 2002 to December 2015. Using daily returns from the NASDAQ Biotechnology Index (NBI), we find that the stock returns were the lowest on Mondays, and compared to the Mondays the stock returns were significantly higher on Wednesdays, Thursdays, and Fridays. Moreover, the results from using the asymmetric GARCH processes reveal that momentum and small-firm effect were positively associated with the market risk-adjusted returns of the biotechnology stocks during this period. Read More

Fast radio bursts are astronomical radio flashes of unknown physical nature with durations of milliseconds. Their dispersive arrival times suggest an extragalactic origin and imply radio luminosities orders of magnitude larger than any other kind of known short-duration radio transient. Thus far, all FRBs have been detected with large single-dish telescopes with arcminute localizations, and attempts to identify their counterparts (source or host galaxy) have relied on contemporaneous variability of field sources or the presence of peculiar field stars or galaxies. Read More

2017Jan
Affiliations: 1JIVE, 2JIVE, 3ASTRON, 4JIVE, 5JIVE, 6Carleton College, 7ASTRON, 8Columbia U, 9ASIAA, 10NRAO Socorro, 11NRAO Socorro, 12JIVE, 13Cornell U, 14Cornell U, 15NRAO Socorro, 16U. of Manchester, 17NAIC Arecibo, 18McGill U, 19UC Berkeley, 20NASA JPL, 21U. of West Virginia Dept. of Physics and Astronomy, 22NRAO CV, 23NAIC Arecibo, 24DRAO, 25NAIC Arecibo, 26UC Berkeley, 27MPIfR, 28McGill U, 29Cornell U

The millisecond-duration radio flashes known as Fast Radio Bursts (FRBs) represent an enigmatic astrophysical phenomenon. Recently, the sub-arcsecond localization (~ 100mas precision) of FRB121102 using the VLA has led to its unambiguous association with persistent radio and optical counterparts, and to the identification of its host galaxy. However, an even more precise localization is needed in order to probe the direct physical relationship between the millisecond bursts themselves and the associated persistent emission. Read More

2017Jan
Affiliations: 1McGill U., 2ASTRON, 3Cornell U., 4ASIAA, 5UC Berkeley, 6Cornell U., 7ASTRON, 8Columbia U., 9NRAO, WVU, 10NRAO, 11NRAO, 12ASTRON, API, 13McGill U., 14JPL, 15ASTRON, 16JIVE, 17WVU, 18JIVE, 19NRAO, 20DRAO, 21Arecibo, 22MPIfR, 23JIVE, Leiden, 24Cornell U.

The precise localization of the repeating fast radio burst (FRB 121102) has provided the first unambiguous association (chance coincidence probability $p\lesssim3\times10^{-4}$) of an FRB with an optical and persistent radio counterpart. We report on optical imaging and spectroscopy of the counterpart and find that it is an extended ($0.6^{\prime\prime}-0. Read More

2017Jan
Affiliations: 1Dept. of Astronomy, University of Florida, 2Dept. of Astronomy, University of Florida, 3CIERA, Northwestern University

We investigate the formation and early evolution of star clusters assuming that they form from a turbulent starless clump of given mass bounded inside a parent self-gravitating molecular cloud characterized by a particular mass surface density. As a first step we assume instantaneous star cluster formation and gas expulsion. We draw our initial conditions from observed properties of starless clumps. Read More

Plages are the magnetically active chromospheric structures prominently visible in Ca $\scriptsize{{\textrm{II}}}$ K line (3933.67 \r{A}). A plage may or may not be associated with a sunspot which is a magnetic structure visible in the solar photosphere. Read More

Electron transfer (ET) in molecular donor-acceptor dye systems is crucial for charge transport in organic semiconductors. Classically, ET rates should decrease with increasing donor-acceptor distance while the microscopic mechanism is more complex and shows intricate dependencies on the excitation conditions. In this paper, we introduce highly soluble N,N'-dialkyl perylene dihydrazides (PDH) - perylene dyes with a dialkylamino -NR$_2$ donor functionality directly bonded to both of their imide nitrogen atoms. Read More

Carrier multiplication by singlet exciton fission enhances photovoltaic conversion efficiencies in organic solids. This decay of one singlet exciton into two triplet states promises to overcome the Shockley-Queisser limit as up to two electrons may be harvested per absorbed photon. Intermolecular coupling is deemed mandatory for both, singlet exciton fission and a band-like transport. Read More

Probabilistic models of directed polymers in random environment have received considerable attention in recent years. Much of this attention has focused on integrable models. In this paper, we introduce some new computational tools that do not require integrability. Read More

The great majority of electronic and optoelectronic devices depends on interfaces between n-type and p-type semiconductors. Finding such matching donor-acceptor systems in molecular crystals remains a challenging endeavor. Structurally compatible molecules may not necessarily be suitable with respect to their optical and electronic properties: large exciton binding energies may favor bound electron-hole pairs rather than charge separation by exciton dissociation, and free, band-like transport is challenging to achieve as hopping commonly dominates charge motion. Read More

We analyze dispersion measure (DM) variations of 37 millisecond pulsars in the 9-year NANOGrav data release and constrain the sources of these variations. Variations are significant for nearly all pulsars, with characteristic timescales comparable to or even shorter than the average spacing between observations. Five pulsars have periodic annual variations, 14 pulsars have monotonically increasing or decreasing trends, and 13 pulsars show both effects. Read More

Plant electrical signals often contains low frequency drifts with or without the application of external stimuli. Quantification of the randomness in plant signals in a stimulus-specific way is hindered because the knowledge of vital frequency information in the actual biological response is not known yet. Here we design an optimum Infinite Impulse Response (IIR) filter which removes the low frequency drifts and preserves the frequency spectrum corresponding to the random component of the unstimulated plant signals by bringing the bias due to unknown artifacts and drifts to a minimum. Read More

Plants sense their environment by producing electrical signals which in essence represent changes in underlying physiological processes. These electrical signals, when monitored, show both stochastic and deterministic dynamics. In this paper, we compute 11 statistical features from the raw non-stationary plant electrical signal time series to classify the stimulus applied (causing the electrical signal). Read More

The study of solar active longitudes has generated a great interest in the recent years. In this work we have used an unique continuous sunspot data series obtained from Kodaikanal observatory and revisited the problem. Analysis of the data shows a persistent presence of the active longitude during the whole 90 years of data duration. Read More

We propose Hilbert transform (HT) and analytic signal (AS) construction for signals over graphs. This is motivated by the popularity of HT, AS, and modulation analysis in conventional signal processing, and the observation that complementary insight is often obtained by viewing conventional signals in the graph setting. Our definitions of HT and AS use a conjugate-symmetry-like property exhibited by the graph Fourier transform (GFT). Read More

In pulsar timing, timing residuals are the differences between the observed times of arrival and the predictions from the timing model. A comprehensive timing model will produce featureless residuals, which are presumably composed of dominating noise and weak physical effects excluded from the timing model (e.g. Read More

Cluster analysis has become one of the most exercised research areas over the past few decades in computer science. As a consequence, numerous clustering algorithms have already been developed to find appropriate partitions of a set of objects. Given multiple such clustering solutions, it is a challenging task to obtain an ensemble of these solutions. Read More

We propose a new class of nonconvex penalty functions in the paradigm of multitask sparse penalized regression that are based on data depth-based inverse ranking. Focusing on a one-step sparse estimator of the coefficient matrix using local linear approximation of the penalty function, we derive its theoretical properties and provide the algorithm for its computation. For orthogonal design and independent responses, the resulting thresholding rule enjoys near-minimax optimal risk performance, similar to the adaptive lasso (Zou, 2006). Read More

We report here the magneto-transport properties of the newly synthesized Heusler compound Cr2NiGa which crystallizes in a disordered cubic B2 structure belonging to Pm-3m space group. The sample is found to be paramagnetic down to 2 K with metallic character. On application of magnetic field, a significantly large increase in resistivity is observed which corresponds to magnetoresistance as high as 112% at 150 kOe of field at the lowest temperature. Read More

It is well known that Kasner geometry with spacelike singularity can be extended to bulk AdS-like geometry, furthermore one can study field theory on this Kasner space via its gravity dual. In this paper, we show that there exists a Kasner-like geometry with timelike singularity for which one can construct a dual gravity description. We then study various minimal surfaces including spacelike geodesics. Read More

Gravitational wave astronomy using a pulsar timing array requires high-quality millisecond pulsars, correctable interstellar propagation delays, and high-precision measurements of pulse times of arrival. Here we identify noise in timing residuals that exceeds that predicted for arrival time estimation for millisecond pulsars observed by the North American Nanohertz Observatory for Gravitational Waves. We characterize the excess noise using variance and structure function analyses. Read More

The Galactic center has some of the highest stellar densities in the Galaxy and a range of interstellar scattering properties that may aid in the detection of new radio-selected transient events. Here we describe a search for radio transients in the Galactic center using over 200 hours of archival data from the Very Large Array (VLA) at 5 and 8.4 GHz. Read More

Structural, resistivity, thermoelectric power and magneto-transport properties of Cu doped Bi2Te3 topological insulators have been investigated. The occurrence of the tuning of charge carriers from n type to p type by Cu doping at Te sites of Bi2Te3 is observed both from Hall effect and thermoelectric power measurements. Carrier mobility decreases with the doping of Cu which provides evidence of the movement of Fermi level from bulk conduction band to the bulk valence band. Read More

2016Sep
Affiliations: 1Department of Physics and Material Sciences Center, Philipps-University Marburg, Germany, 2Institute of Applied Physics, Justus-Liebig-University Giessen, Germany, 3Institute of Experimental Physics I, Justus-Liebig-University Giessen, Germany, 4Institute of Experimental Physics I, Justus-Liebig-University Giessen, Germany, 5Institute of Applied Physics, Justus-Liebig-University Giessen, Germany, 6Department of Physics and Material Sciences Center, Philipps-University Marburg, Germany

We studied the electron transfer from excitons in adsorbed indoline dye layers across the organic-inorganic interface. The hybrids consist of indoline derivatives on the one hand and different inorganic substrates (TiO$_2$, ZnO, SiO$_2$(0001), fused silica) on the other. We reveal the electron transfer times from excitons in dye layers to the organic-inorganic interface by analyzing the photoluminescence transients of the dye layers after femtosecond excitation and applying kinetic model calculations. Read More

Using numerical models for star clusters spanning a wide range in ages and metallicities (Z) we study the masses of binary black holes (BBHs) produced dynamically and merging in the local universe ($z\lesssim0.2$). After taking into account cosmological constraints on star-formation rate and metallicity evolution, which realistically relate merger delay times obtained from models with merger redshifts, we show here for the first time that while old, metal-poor globular clusters can naturally produce merging BBHs with heavier components, as observed in GW150914, lower-mass BBHs like GW151226 are easily formed dynamically in younger, higher-metallicity clusters. Read More

While most studies emphasize on certain aspects of Pathogen-Host Interactions (PHI), such as the preferential attachment of bacteria or virus to its human receptor homolog, studies have attempted to methodically classify interactions among pathogenic proteins and their host proteins. Here we have analyzed 182 pathogens from The Pathogen-Host Interaction Search Tool (PHISTO) and could identify the proteins/protein coding genes that act on both virus and bacteria. Importantly there were few proteins viz. Read More

Providing opinions through labeling of images, tweets, etc. have drawn immense interest in crowdsourcing markets. This invokes a major challenge of aggregating multiple opinions received from different crowd workers for deriving the final judgment. Read More

In presence of multiple clustering solutions for the same dataset, a clustering ensemble approach aims to yield a single clustering of the dataset by achieving a consensus among the input clustering solutions. The goal of this consensus is to improve the quality of clustering. It has been seen that there are some image clustering tasks that cannot be easily solved by computer. Read More

We present the improved visibility based Tapered Gridded Estimator (TGE) for the power spectrum of the diffuse sky signal. The visibilities are gridded to reduce the computation, and tapered through a convolution to suppress the contribution from the outer regions of the telescope's field of view. The TGE also internally estimates the noise bias, and subtracts this out to give an unbiased estimate of the power spectrum. Read More

We report the discovery and timing results for five millisecond pulsars (MSPs) from the Arecibo PALFA survey: PSRs J1906+0055, J1914+0659, J1933+1726, J1938+2516, and J1957+2516. Timing observations of the 5 pulsars were conducted with the Arecibo and Lovell telescopes for time spans ranging from 1.5 to 3. Read More

We report on the discovery and timing observations of 29 distant long-period pulsars discovered in the ongoing Arecibo PALFA pulsar survey. Following discovery with the Arecibo Telescope, confirmation and timing observations of these pulsars over several years at Jodrell Bank Observatory have yielded high-precision positions and measurements of rotation and radiation properties. We have used multi-frequency data to measure the interstellar scattering properties of some of these pulsars. Read More

We report the discovery of two long-term intermittent radio pulsars in the ongoing Arecibo PALFA pulsar survey. Following discovery with the Arecibo Telescope, extended observations of these pulsars over several years at Jodrell Bank Observatory have revealed the details of their rotation and radiation properties. PSRs J1910+0517 and J1929+1357 show long-term extreme bi-modal intermittency, switching between active (ON) and inactive (OFF) emission states and indicating the presence of a large, hitherto unrecognised, underlying population of such objects. Read More

Several time dependent backgrounds, with perfect fluid matter, can be used to construct solutions of Einstein equations in the presence of a negative cosmological constant along with some matter sources. In this work we focus on the non-vacuum Kasner-AdS geometry and its solitonic generalization. To characterize these space-times, we provide ways to embed them in higher dimensional flat space-times. Read More

In this article, we report negative thermal expansion and spin frustration in hexagonal GdInO$_{3}$. Rietveld refinement of the XRD patterns reveal that the negative thermal expansion in the temperature range of 50-100K stems from the triangular lattice of Gd$^{3+}$ ions. At low temperature, the downward deviation of the inverse susceptibility ($\chi^{-1}$) vs. Read More

Dynamic cooperativity in monomeric enzymes is characterized in terms of a non-Michaelis-Menten kinetic behaviour. The latter is believed to be associated with mechanisms that include multiple reaction pathways due to enzymatic conformational fluctuations. Recent advances in single-molecule fluorescence spectroscopy have provided new fundamental insights on the possible mechanisms underlying reactions catalyzed by fluctuating enzymes. Read More

Ultra-relativistic Heavy-Ion Collision (HIC) generates very strong initial magnetic field ($\vec B$) inducing a vorticity in the reaction plane. The high $\vec{B}$ influences the evolution dynamics that is opposed by the large Faraday current due to electric field generated by the time varying $\vec{B}$. We show that the resultant effects entail a significantly large directed flow ($v_1$) of charm quarks (CQs) compared to light quarks due to a combination of several favorable conditions for CQs, mainly: (i) unlike light quarks formation time scale of CQs, $\tau_f \simeq \, 0. Read More