Results for "Michael Tsang"

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Detecting Statistical Interactions from Neural Network WeightsMay 14 2017Feb 27 2018Interpreting neural networks is a crucial and challenging task in machine learning. In this paper, we develop a novel framework for detecting statistical interactions captured by a feedforward multilayer neural network by directly interpreting its learned ... More
Bandwidth Allocation and Resource Adjustment for Stability Enhancement in Complex NetworksAug 27 2019We introduce the message passing algorithm and discrete Green's function to elucidate how resource fluctuations determine flow fluctuations in a network optimizing a global cost function. To enhance the robustness of the network against fluctuations, ... More
Linear Corotation Torques in Non-Barotropic DisksOct 31 2013Jan 13 2014I derive a fully analytic expression for the linear corotation torque to first order in eccentricity for planets in non-barotropic protoplanetary disks, taking into account the effect of disk entropy gradients. This torque formula is applicable to both ... More
Protoplanetary Disk Resonances and Type I MigrationJul 20 2011Oct 03 2011Waves reflected by the inner edge of a protoplanetary disk are shown to significantly modify Type I migration, even allowing the trapping of planets near the inner disk edge for small planets in a range of disk parameters. This may inform the distribution ... More
N derivatives are necessary for order N+1 convergence in quadrature: a converse resultJan 28 2014Results on the error bounds of quadrature methods are well known - most state that if the method has degree N, and the integrand has N derivatives, then the error is order N+1. We prove here a converse: that if the integrand fails to have N derivatives, ... More
Can Neutron-Star Mergers Explain the r-process Enrichment in Globular Clusters?Jun 26 2019Star-to-star dispersion of r-process elements has been observed in a significant number of old, metal-poor globular clusters. We investigate early-time neutron-star mergers as the mechanism for this enrichment. We show that neutron-star mergers cannot ... More
Quantum optimality of photon counting for temperature measurement of thermal astronomical sourcesApr 08 2015Jul 28 2015Using the quantum Cram\'{e}r-Rao bound from quantum estimation theory, we derive a fundamental quantum limit on the sensitivity of a temperature measurement of a thermal astronomical source. This limit is expressed in terms of the source temperature $T_s$, ... More
Fundamental quantum limits to waveform detectionApr 17 2012Oct 16 2012Ever since the inception of gravitational-wave detectors, limits imposed by quantum mechanics to the detection of time-varying signals have been a subject of intense research and debate. Drawing insights from quantum information theory, quantum detection ... More
Black Magic Investigation Made Simple: Monte Carlo Simulations and Historical Back Testing of Momentum Cross-Over Strategies Using FRACTI PatternsAug 23 2018To promote economic stability, finance should be studied as a hard science, where scientific methods apply. When a trading strategy is proposed, the underlying model should be transparent and defined robustly to allow other researchers to understand and ... More
Extracting Interpretable Concept-Based Decision Trees from CNNsJun 11 2019In an attempt to gather a deeper understanding of how convolutional neural networks (CNNs) reason about human-understandable concepts, we present a method to infer labeled concept data from hidden layer activations and interpret the concepts through a ... More
Extracting Interpretable Concept-Based Decision Trees from CNNsJun 11 2019Jun 16 2019In an attempt to gather a deeper understanding of how convolutional neural networks (CNNs) reason about human-understandable concepts, we present a method to infer labeled concept data from hidden layer activations and interpret the concepts through a ... More
The Blue Box White PaperOct 29 2013This white paper is an explanation of Ben and Dave's TARDIS time machine, written for laypeople who are interested in time travel, but have no technical knowledge of Einstein's Theory of General Relativity. The first part of this paper is an introduction ... More
Timing Noise in Pulsars and Magnetars and the Magnetospheric Moment of InertiaFeb 18 2013Jul 17 2013We examine timing noise in both magnetars and regular pulsars, and find that there exists a component of the timing noise with strong magnetic field dependence above B ~ 10^{12.5} G. The dependence of the timing noise floor on the magnetic field is also ... More
The inverse Compton catastrophe and high brightness temperature radio sourcesNov 21 2006The occurrence of the inverse Compton catastrophe when the synchrotron brightness temperature exceeds a threshold value, usually estimated to be 10^{12} K, appears to be in contradiction with observation because: (i) the threshold is substantially exceeded ... More
Curriculum Loss: Robust Learning and Generalization against Label CorruptionMay 24 2019May 28 2019Generalization is vital important for many deep network models. It becomes more challenging when high robustness is required for learning with noisy labels. The 0-1 loss has monotonic relationship between empirical adversary (reweighted) risk, and it ... More
Can I trust you more? Model-Agnostic Hierarchical ExplanationsDec 12 2018Interactions such as double negation in sentences and scene interactions in images are common forms of complex dependencies captured by state-of-the-art machine learning models. We propose Mah\'e, a novel approach to provide Model-agnostic hierarchical ... More
Latent Adversarial Defence with Boundary-guided GenerationJul 16 2019Deep Neural Networks (DNNs) have recently achieved great success in many tasks, which encourages DNNs to be widely used as a machine learning service in model sharing scenarios. However, attackers can easily generate adversarial examples with a small ... More
Complementary Attributes: A New Clue to Zero-Shot LearningApr 17 2018Jul 22 2019Zero-shot learning (ZSL) aims to recognize unseen objects using disjoint seen objects via sharing attributes. The generalization performance of ZSL is governed by the attributes, which transfer semantic information from seen classes to unseen classes. ... More
Matching Pursuit LASSO Part II: Applications and Sparse Recovery over Batch SignalsFeb 20 2013Dec 24 2014Matching Pursuit LASSIn Part I \cite{TanPMLPart1}, a Matching Pursuit LASSO ({MPL}) algorithm has been presented for solving large-scale sparse recovery (SR) problems. In this paper, we present a subspace search to further improve the performance of MPL, ... More
Hierarchical Maximum Margin Learning for Multi-Class ClassificationFeb 14 2012Due to myriads of classes, designing accurate and efficient classifiers becomes very challenging for multi-class classification. Recent research has shown that class structure learning can greatly facilitate multi-class learning. In this paper, we propose ... More
Constraints on Skyrme Equations of State from Doubly Magic Nuclei, Ab-Initio Calculations of Low-Density Neutron Matter, and Neutron StarsAug 30 2019We use properties of doubly-magic nuclei, ab-initio calculations of low-density neutron matter, and of neutron stars to constrain the parameters of the Skyrme energy-density functional. We find all of these properties can be reproduced within a constrained ... More
The quantum Bell-Ziv-Zakai bounds and Heisenberg limits for waveform estimationSep 28 2014We propose quantum versions of the Bell-Ziv-Zakai lower bounds on the error in multiparameter estimation. As an application we consider measurement of a time-varying optical phase signal with stationary Gaussian prior statistics and a power law spectrum ... More
Parameterized tests of the strong-field dynamics of general relativity using gravitational wave signals from coalescing binary black holes: Fast likelihood calculations and sensitivity of the methodDec 23 2017Feb 27 2018Thanks to the recent discoveries of gravitational wave signals from binary black hole mergers by Advanced Laser Interferometer Gravitational Wave Observatory and Advanced Virgo, the genuinely strong-field dynamics of spacetime can now be probed, allowing ... More
Subdiffraction incoherent optical imaging via spatial-mode demultiplexingAug 09 2016I propose a spatial-mode demultiplexing (SPADE) scheme for the far-field imaging of arbitrary incoherent optical sources. For an object too small to be resolved by direct imaging under the diffraction limit, I show that SPADE can estimate the moments ... More
Video Contents Prior Storing Server for Optical Access NetworkApr 08 2015One of the most important multimedia applications is Internet protocol TV (IPTV) for next-generation networks. IPTV provides triple-play services that require high-speed access networks with the functions of multicasting and quality of service (QoS) guarantees. ... More
Quantum Semiparametric EstimationJun 24 2019Jul 08 2019In the study of quantum limits to parameter estimation, the high dimensionality of the density operator and that of the unknown parameters have long been two of the most difficult challenges. Here I propose a theory of quantum semiparametric estimation ... More
Quantum limits on the time-bandwidth product of an optical resonatorSep 28 2017Dec 22 2017A thought-provoking proposal by Tsakmakidis et al. [Science 356, 1260 (2017)] suggests that nonreciprocal optics can break a time-bandwidth limit to passive resonators. Here I quantize their resonator model and show that quantum mechanics does impose ... More
Quantum Imaging beyond the Diffraction Limit by Optical Centroid MeasurementsJan 30 2009Jun 22 2009I propose a quantum imaging method that can beat the Rayleigh-Abbe diffraction limit and achieve de Broglie resolution without requiring a multiphoton absorber as the detector. Using the same non-classical states of light as those for quantum lithography, ... More
Multiparameter Heisenberg limitMar 17 2014Feb 01 2016Using a quantum version of the Bell-Ziv-Zakai bound, I derive a Heisenberg limit to multiparameter estimation for any Gaussian prior probability density. The mean-square error lower bound is shown to have a universal quadratic scaling with respect to ... More
Optimal waveform estimation for classical and quantum systems via time-symmetric smoothing. II. Applications to atomic magnetometry and Hardy's paradoxSep 13 2009The quantum smoothing theory [Tsang, Phys. Rev. Lett. 102, 250403 (2009); Phys. Rev. A, in press (e-print arXiv:0906.4133)] is extended to account for discrete jumps in the classical random process to be estimated, discrete variables in the quantum system, ... More
Optimal waveform estimation for classical and quantum systems via time-symmetric smoothingJun 22 2009Aug 11 2009Classical and quantum theories of time-symmetric smoothing, which can be used to optimally estimate waveforms in classical and quantum systems, are derived using a discrete-time approach, and the similarities between the two theories are emphasized. Application ... More
Decoherence of Quantum-Enhanced Timing AccuracyApr 05 2007Quantum enhancement of optical pulse timing accuracy is investigated in the Heisenberg picture. Effects of optical loss, group-velocity dispersion, and Kerr nonlinearity on the position and momentum of an optical pulse are studied via Heisenberg equations ... More
Semiparametric estimation for incoherent optical imagingJun 11 2019Jun 17 2019The theory of semiparametric estimation offers an elegant way of computing the Cram\'er-Rao bound for a parameter of interest in the midst of infinitely many nuisance parameters. Here I apply the theory to the problem of moment estimation for incoherent ... More
Temperature determination from the lattice gas modelSep 30 1996Determination of temperature from experimental data has become important in searches for critical phenomena in heavy ion collisions. Widely used methods are ratios of isotopes (which rely on chemical and thermal equilibrium), population ratios of excited ... More
Liquid-gas phase transition in nuclear multifragmentationSep 11 2000Oct 23 2000The equation of state of nuclear matter suggests that at suitable beam energies the disassembling hot system formed in heavy ion collisions will pass through a liquid-gas coexistence region. Searching for the signatures of the phase transition has been ... More
Subdiffraction incoherent optical imaging via spatial-mode demultiplexingAug 09 2016Nov 15 2016I propose a spatial-mode demultiplexing (SPADE) measurement scheme for the far-field imaging of arbitrary incoherent optical sources. For any object too small to be resolved by direct imaging under the diffraction limit, I show that SPADE can estimate ... More
The parametrized probabilistic finite-state transducer probe game player fingerprint modelJan 29 2014Fingerprinting operators generate functional signatures of game players and are useful for their automated analysis independent of representation or encoding. The theory for a fingerprinting operator which returns the length-weighted probability of a ... More
Semiparametric estimation for incoherent optical imagingJun 11 2019The theory of semiparametric estimation offers an elegant way to compute the Cram\'er-Rao bound for a parameter of interest in the midst of infinitely many nuisance parameters. Here I apply the theory to the problem of moment estimation for incoherent ... More
Realizable classes and embedding problemsFeb 07 2016Jul 25 2016Let $K$ be a number field with ring of integers $\mathcal{O}_K$ and let $G$ be a finite group. Given a $G$-Galois $K$-algebra $K_h$, let $\mathcal{O}_h$ denote its ring of integers. If $K_h/K$ is tame, then a classical theorem of E. Noether implies that ... More
On the multiple holomorph of groups of squarefree or odd prime power orderJun 20 2019Let $G$ be a group and write $\mbox{Perm}(G)$ for its symmetric group. Define $\mbox{Hol}(G)$ to be the holomorph of $G$, regarded as a subgroup of $\mbox{Perm}(G)$, and let $\mbox{NHol}(G)$ denote its normalizer. The quotient $T(G) = \mbox{NHol}(G)/\mbox{Hol}(G)$ ... More
Quantum limit to subdiffraction incoherent optical imagingJun 07 2018Jan 03 2019The application of quantum estimation theory to the problem of imaging two incoherent point sources has recently led to new insights and better measurements for incoherent imaging and spectroscopy. To establish a more general limit beyond the case of ... More
Subdiffraction incoherent optical imaging via spatial-mode demultiplexingAug 09 2016Feb 28 2017I propose a spatial-mode demultiplexing (SPADE) measurement scheme for the far-field imaging of spatially incoherent optical sources. For any object too small to be resolved by direct imaging under the diffraction limit, I show that SPADE can estimate ... More
Quantum metrology with open dynamical systemsJan 24 2013Jun 12 2013This paper studies quantum limits to dynamical sensors in the presence of decoherence. A modified purification approach is used to obtain tighter quantum detection and estimation error bounds for optical phase sensing and optomechanical force sensing. ... More
Spectral phase conjugation via extended phase matchingJun 15 2005Nov 21 2005It is shown that the copropagating three-wave-mixing parametric process, with appropriate type-II extended phase matching and pumped with a short second-harmonic pulse, can perform spectral phase conjugation and parametric amplification, which shows a ... More
Ziv-Zakai Error Bounds for Quantum Parameter EstimationNov 15 2011May 10 2012I propose quantum versions of the Ziv-Zakai bounds as alternatives to the widely used quantum Cram\'er-Rao bounds for quantum parameter estimation. From a simple form of the proposed bounds, I derive both a "Heisenberg" error limit that scales with the ... More
Quantum Nonlocality in Weak-Thermal-Light InterferometryAug 08 2011Nov 17 2011In astronomy, interferometry of light collected by separate telescopes is often performed by physically bringing the optical paths together in the form of Young's double-slit experiment. Optical loss severely limits the efficiency of this so-called direct ... More
Quantum Semiparametric EstimationJun 24 2019In the study of quantum limits to parameter estimation, the high dimensionality of the density operator and that of the unknown parameters have long been two of the most difficult challenges. Here I propose a theory of quantum semiparametric estimation ... More
Conservative error measures for classical and quantum metrologyMay 12 2016The classical and quantum Cram\'er-Rao bounds have become standard measures of parameter-estimation uncertainty for a variety of sensing and imaging applications in recent years, but their assumption of unbiased estimators potentially undermines their ... More
Hopf-Galois structures on a Galois $S_n$-extensionDec 16 2018In this paper, we shall determine the exact number of Hopf-Galois structures on a Galois $S_n$-extension, where $S_n$ denotes the symmetric group on $n$ letters.
On the multiple holomorph of a finite almost simple groupApr 22 2019Let $G$ be a group and write $\mbox{Perm}(G)$ for its symmetric group. The holomorph $\mbox{Hol}(G)$ of $G$ is defined to be the normalizer of the subgroup of left translations in $\mbox{Perm}(G)$. Its normalizer $\mbox{NHol}(G)$ in $\mbox{Perm}(G)$ in ... More
On the multiple holomorph of a finite almost simple groupApr 22 2019May 29 2019Let $G$ be a group. Let $\mathrm{Perm}(G)$ denote its symmetric group and write $\mathrm{Hol}(G)$ for the normalizer of the subgroup of left translations in $\mathrm{Perm}(G)$. The multiple holomorph $\mathrm{NHol}(G)$ of $G$ is in turn defined to be ... More
Non-existence of Hopf-Galois structures and bijective crossed homomorphismsMay 28 2018Sep 15 2018By work of C. Greither and B. Pareigis as well as N. P. Byott, the enumeration of Hopf-Galois structures on a Galois extension of fields with Galois group $G$ may be reduced to that of regular subgroups of $\mbox{Hol}(N)$ isomorphic to $G$ as $N$ ranges ... More
On the self-duality of rings of integers in tame and abelian extensionsMar 09 2017Dec 06 2018Let $L/K$ be a tame and Galois extension of number fields with group $G$. It is well-known that any ambiguous ideal in $L$ is locally free over $\mathcal{O}_KG$ (of rank one), and so it defines a class in the locally free class group of $\mathcal{O}_KG$, ... More
Quantum limits to optical point-source localizationNov 11 2014Jul 27 2015Motivated by the importance of optical microscopes to science and engineering, scientists have pondered for centuries how to improve their resolution and the existence of fundamental resolution limits. In recent years, a new class of microscopes that ... More
Mismatched Quantum Filtering and Entropic InformationOct 01 2013Jan 27 2014Quantum filtering is a signal processing technique that estimates the posterior state of a quantum system under continuous measurements and has become a standard tool in quantum information processing, with applications in quantum state preparation, quantum ... More
Beating the spatial standard quantum limits via adiabatic soliton expansionApr 18 2006May 09 2006Spatial quantum enhancement effects are studied under a unified framework. It is shown that the multiphoton absorption rate of photons with a quantum-enhanced lithographic resolution is reduced, not enhanced, contrary to popular belief. The use of adiabatic ... More
Quantum Semiparametric EstimationJun 24 2019Jul 31 2019In the study of quantum limits to parameter estimation, the high dimensionality of the density operator and that of the unknown parameters have long been two of the most difficult challenges. Here I propose a theory of quantum semiparametric estimation ... More
Estimating Robot Strengths with Application to Selection of Alliance Members in FIRST Robotics CompetitionsOct 12 2018Jun 20 2019Since the inception of the FIRST, which is an international youth organization "For Inspiration and Recognition of Science and Technology", Robotics Competition (FRC) and its special playoff system, robotics teams have longed to appropriately quantify ... More
Shattering Flares During Close Encounters of Neutron StarsJul 12 2013We demonstrate that resonant shattering flares can occur during close passages of neutron stars in eccentric or hyperbolic encounters. We provide updated estimates for the rate of close encounters of compact objects in dense stellar environments, which ... More
On the Galois module structure of the square root of the inverse different in abelian extensionsJul 16 2014Jun 09 2015Let $K$ be a number field with ring of integers $\mathcal{O}_K$ and $G$ a finite group of odd order. If $K_h$ is a weakly ramified $G$-Galois $K$-algebra, then its square root $A_h$ of the inverse different is a locally free $\mathcal{O}_{K}G$-module ... More
Hopf-Galois structures on a Galois $S_n$-extensionDec 16 2018May 20 2019In this paper, we shall determine the exact number of Hopf-Galois structures on a Galois $S_n$-extension, where $S_n$ denotes the symmetric group on $n$ letters.
Galois module structure of the square root of the inverse different over maximal ordersJul 25 2016Let $K$ be a number field with ring of integers $\mathcal{O}_K$ and let $G$ be a \mbox{finite group of} odd order. Given a $G$-Galois $K$-algebra $K_h$, let $A_h$ be the square root of the inverse different of $K_h/K$, which exists by Hilbert's formula. ... More
Quantum Semiparametric EstimationJun 24 2019Jun 27 2019In the study of quantum limits to parameter estimation, the high dimensionality of the density operator and that of the unknown parameters have long been two of the most difficult challenges. Here I propose a theory of quantum semiparametric estimation ... More
Resolving starlight: a quantum perspectiveJun 05 2019The wave-particle duality of light introduces two fundamental problems to imaging, namely, the diffraction limit and the photon shot noise. Quantum information theory can tackle them both in one holistic formalism: model the light as a quantum object, ... More
Conservative classical and quantum resolution limits for incoherent imagingMay 12 2016Mar 26 2017I propose classical and quantum limits to the statistical resolution of two incoherent optical point sources from the perspective of minimax parameter estimation. Unlike earlier results based on the Cram\'er-Rao bound, the limits proposed here, based ... More
A Bayesian quasi-probability approach to inferring the past of quantum observablesMar 13 2014Apr 01 2014I describe a method of inferring the past of quantum observables given the initial state and the subsequent measurement results using Wigner quasi-probability representations. The method is proved to be compatible with logic for large subclasses of quantum ... More
Testing quantum mechanics: a statistical approachJun 12 2013Jan 27 2014As experiments continue to push the quantum-classical boundary using increasingly complex dynamical systems, the interpretation of experimental data becomes more and more challenging: when the observations are noisy, indirect, and limited, how can we ... More
Continuous Quantum Hypothesis TestingOct 23 2011Apr 27 2012I propose a general quantum hypothesis testing theory that enables one to test hypotheses about any aspect of a physical system, including its dynamics, based on a series of observations. For example, the hypotheses can be about the presence of a weak ... More
Time-Symmetric Quantum Theory of SmoothingApr 13 2009Jul 14 2009Smoothing is an estimation technique that takes into account both past and future observations, and can be more accurate than filtering alone. In this Letter, a quantum theory of smoothing is constructed using a time-symmetric formalism, thereby generalizing ... More
Fundamental Quantum Limit to Multiphoton Absorption Rate for Monochromatic LightFeb 04 2008Jul 22 2008The local multiphoton absorption rate for an arbitrary quantum state of monochromatic light, taking into account the photon number, momentum, and polarization degrees of freedom, is shown to have an upper bound that can be reached by coherent fields. ... More
Quantum temporal correlations and entanglement via adiabatic control of vector solitonsMar 10 2006May 29 2007It is shown that optical pulses with a mean position accuracy beyond the standard quantum limit can be produced by adiabatically expanding an optical vector soliton followed by classical dispersion management. The proposed scheme is also capable of entangling ... More
Cavity quantum electro-optics. II. Input-output relations between traveling optical and microwave fieldsMay 11 2011Aug 12 2011In the previous paper [M. Tsang, Phys. Rev. A 81, 063837 (2010), e-print arXiv:1003.0116], I proposed a quantum model of a cavity electro-optic modulator, which can coherently couple an optical cavity mode to a microwave resonator mode and enable novel ... More
Cavity quantum electro-opticsFeb 27 2010Jun 30 2010The quantum dynamics of the coupling between a cavity optical field and a resonator microwave field via the electro-optic effect is studied. This coupling has the same form as the opto-mechanical coupling via radiation pressure, so all previously considered ... More
Subspace Methods That Are Resistant to a Limited Number of Features Corrupted by an AdversaryFeb 19 2019Jul 29 2019In this paper, we consider batch supervised learning where an adversary is allowed to corrupt instances with arbitrarily large noise. The adversary is allowed to corrupt any $l$ features in each instance and the adversary can change their values in any ... More
Domain-adversarial Network AlignmentAug 15 2019Network alignment is a critical task to a wide variety of fields. Many existing works leverage on representation learning to accomplish this task without eliminating domain representation bias induced by domain-dependent features, which yield inferior ... More
Energy-Efficient Sensor Censoring for Compressive Distributed Sparse Signal RecoveryDec 05 2017Jan 15 2018To strike a balance between energy efficiency and data quality control, this paper proposes a sensor censoring scheme for distributed sparse signal recovery via compressive-sensing based wireless sensor networks. In the proposed approach, each sensor ... More
Hyperuniform disordered photonic crystal polarizersAug 02 2019Aug 11 2019An ultra-broadband transverse magnetic (TM) pass hyperuniform disordered photonic crystal (HUDPC) polarizer is proposed and demonstrated on a silicon-on-insulator platform. Propagation of the transverse electric mode is blocked by three combined effects, ... More
Fourier sparsity, spectral norm, and the Log-rank conjectureApr 04 2013Apr 09 2013We study Boolean functions with sparse Fourier coefficients or small spectral norm, and show their applications to the Log-rank Conjecture for XOR functions f(x\oplus y) --- a fairly large class of functions including well studied ones such as Equality ... More
On the realizable classes of the square root of the inverse different in the unitary class groupSep 21 2015Dec 08 2015Let $K$ be a number field with ring of integers $\mathcal{O}_K$ and let $G$ be a finite abelian group of odd order. Given a $G$-Galois $K$-algebra $K_h$, let $A_h$ denote its square root of the inverse different, which exists by Hilbert's formula. If ... More
Hopf-Galois structures of isomorphic type on a non-abelian characteristically simple extensionNov 28 2018Mar 15 2019Let $L/K$ be a finite Galois extension whose Galois group $G$ is non-abelian and characteristically simple. Using tools from graph theory, we shall give a closed formula for the number of Hopf-Galois structures on $L/K$ with associated group isomorphic ... More
Subdiffraction incoherent optical imaging via spatial-mode demultiplexing: semiclassical treatmentMar 26 2017Feb 21 2018I present a semiclassical analysis of a spatial-mode demultiplexing (SPADE) measurement scheme for far-field incoherent optical imaging under the effects of diffraction and photon shot noise. Building on previous results that assume two point sources ... More
Volterra filters for quantum estimation and detectionSep 07 2015Dec 14 2015The implementation of optimal statistical inference protocols for high-dimensional quantum systems is often computationally expensive. To avoid the difficulties associated with optimal techniques, here I propose an alternative approach to quantum estimation ... More
Quantum transition-edge detectorsMay 08 2013Aug 14 2013Small perturbations to systems near critical points of quantum phase transitions can induce drastic changes in the system properties. Here I show that this sensitivity can be exploited for weak-signal detection applications. This is done by relating a ... More
Ultimate Energy Densities for Electromagnetic PulsesMar 06 2008The ultimate electric and magnetic energy densities that can be attained by bandlimited electromagnetic pulses in free space are calculated using an ab initio quantized treatment, and the quantum states of electromagnetic fields that achieve the ultimate ... More
On the Relationship between Resolution Enhancement and Multiphoton Absorption Rate in Quantum LithographyJul 17 2006Feb 28 2007The proposal of quantum lithography [Boto et al., Phys. Rev. Lett. 85, 2733 (2000)] is studied via a rigorous formalism. It is shown that, contrary to Boto et al.'s heuristic claim, the multiphoton absorption rate of a ``NOON'' quantum state is actually ... More
Degeneration in VAE: in the Light of Fisher Information LossFeb 19 2018Sep 25 2018While enormous progress has been made to Variational Autoencoder (VAE) in recent years, similar to other deep networks, VAE with deep networks suffers from the problem of degeneration, which seriously weakens the correlation between the input and the ... More
On the solvability of regular subgroups in the holomorph of a finite solvable groupJan 30 2019In this paper, we shall exhibit an infinite family of non-solvable numbers $n$ for which the holomorph of any solvable group of order $n$ has no insolvable regular subgroup.
Corotational Damping of Diskoseismic C-modes in Black Hole Accretion DiscsOct 07 2008Nov 14 2008Diskoseismic c-modes in accretion discs have been invoked to explain low-frequency variabilities observed in black-hole X-ray binaries. These modes are trapped in the inner-most region of the disc and have frequencies much lower than the rotation frequency ... More
Electromagnetically induced transparency and optical memories in an optomechanical system with $N$ membranesMar 06 2014We study the propagation of a weak probe field through an optomechanical system in which $N$ nearly degenerate mechanical membranes are inside a Febry-Perot cavity, and couple dispersively to an intracavity field. We derive a general analytical expression ... More
Coupled-Resonator Optical Near-Field LithographyApr 21 2008The problem of pattern formation in resonantly-enhanced near-field lithography by the use of dielectric or plasmonic planar resonators is investigated. Sub-diffraction-limited bright or dark spots can be produced by taking advantage of the rotational ... More
Mode-Division Multiplexing for Silicon Photonic Network-on-chipFeb 09 2017Optical interconnect is a potential solution to attain the large bandwidth on-chip communications needed in high performance computers in a low power and low cost manner. Mode-division multiplexing (MDM) is an emerging technology that scales the capacity ... More
Self-Trapping of Diskoseismic Corrugation Modes in Neutron Star SpacetimesNov 05 2015We examine the effects of higher-order multipole contributions of rotating neutron star (NS) spacetimes on the propagation of corrugation (c-)modes within a thin accretion disk. We find that the Lense-Thirring precession frequency, which determines the ... More
Magnifying perfect lens and superlens design by coordinate transformationAug 02 2007Nov 29 2007The coordinate transformation technique is applied to the design of perfect lenses and superlenses. In particular, anisotropic metamaterials that magnify two-dimensional planar images beyond the diffraction limit are designed by the use of oblate spheroidal ... More
Far-field Superresolution of Thermal Electromagnetic Sources at the Quantum LimitApr 04 2016Nov 28 2016We obtain the ultimate quantum limit for estimating the transverse separation of two thermal point sources using a given imaging system with limited spatial bandwidth. We show via the quantum Cram\'er-Rao bound that, contrary to the Rayleigh limit in ... More
A Multiple Source Hourglass Deep Network for Multi-Focus Image FusionAug 28 2019Multi-Focus Image Fusion seeks to improve the quality of an acquired burst of images with different focus planes. For solving the task, an activity level measurement and a fusion rule are typically established to select and fuse the most relevant information ... More
Meta-surface-enabled ultra-sharp multimode waveguide bends on siliconOct 14 2018Mode-division-multiplexing (MDM) is attractive as a means to increase the link capacity of a single wavelength for optical interconnects via the use of multiple mode-channels in multimode bus waveguide.In order to route the data in MDM systems, waveguide ... More
Far-field Super-resolution of Thermal Electromagnetic Sources at the Quantum LimitApr 04 2016Jul 06 2016We obtain the ultimate quantum limit for estimating the transverse separation of two thermal point sources using a given imaging system with limited spatial bandwidth. Via the quantum Cramer-Rao bound, we show that, contrary to the Rayleigh limit in conventional ... More
On the solvability of regular subgroups in the holomorph of a finite solvable groupJan 30 2019Mar 20 2019In this paper, we shall exhibit an infinite family of non-solvable numbers $n$ for which the holomorph of any solvable group of order $n$ has no insolvable regular subgroup.
Third Order Intermodulation Power Estimation for N Sinusoidal ChannelsNov 23 2013In this paper analysis is given to find the third order intermodulation power given sinusoids are fed into a nonlinear device. A simple expression of the third order intermodulation power is given for the case that the center frequencies of the input ... More
Corotational Instability of Inertial-Acoustic Modes in Black Hole Accretion Discs and Quasi-Periodic OscillationsOct 01 2008Nov 14 2008We study the global stability of non-axisymmetric p-modes (also called inertial-acoustic modes) trapped in the inner-most regions of accretion discs around black holes. We show that the lowest-order (highest-frequency) p-modes, with frequencies $\omega=(0.5-0.7) ... More