cssi/SciSciGPT-SciSciNet huggingface dataset:
Deep Learning Reveals Underlying Physics of Light–Matter Interactions in Nanophotonic Devices

In this paper, we present a deep learning-based (DL-based) algorithm, as a purely mathematical platform, for providing intuitive understanding of the properties of electromagnetic (EM) wave-matter interaction in nanostructures. This approach is based on using the dimensionality reduction (DR) technique to significantly reduce the dimensionality of a generic EM wave-matter interaction problem without imposing significant error. Such an approach implicitly provides useful information about the role of different features (or design parameters such as geometry) of the nanostructure in its response functionality. To demonstrate the practical capabilities of this DL-based technique, we apply it to a reconfigurable optical metadevice enabling dual-band and triple-band optical absorption in the telecommunication window. Combination of the proposed approach with existing commercialized full-wave simulation tools offers a powerful toolkit to extract basic mechanisms of wave-matter interaction in complex EM devices and facilitate the design and optimization of nanostructures for a large range of applications including imaging, spectroscopy, and signal processing. It is worth to mention that the demonstrated approach is general and can be used in a large range of problems as long as enough training data can be provided.
Effects of fluid velocity gradients on heavy quark energy loss

We use holographic duality to analyze the drag force on, and consequent energy loss of, a heavy quark moving through a strongly coupled conformal fluid with non-vanishing gradients in its velocity and temperature. We derive the general expression for the drag force to first order in the fluid gradients. Using this general expression, we show that a quark that is instantaneously at rest, relative to the fluid, in a fluid whose velocity is changing with time feels a nonzero force. And, we show that for a quark that is moving ultra-relativistically, the first order gradient “corrections” become larger than the zeroth order drag force, suggesting that the gradient expansion may be unreliable in this regime. We illustrate the importance of the fluid gradients for heavy quark energy loss by considering a fluid with one-dimensional boost invariant Bjorken expansion as well as the strongly coupled plasma created by colliding sheets of energy.
Free-standing silicon shadow masks for transmon qubit fabrication

Nanofabrication techniques for superconducting qubits rely on resist-based masks patterned by electron-beam or optical lithography. We have developed an alternative nanofabrication technique based on free-standing silicon shadow masks fabricated from silicon-on-insulator wafers. These silicon shadow masks not only eliminate organic residues associated with resist-based lithography, but also provide a pathway to better understand and control surface-dielectric losses in superconducting qubits by decoupling mask fabrication from substrate preparation. We have successfully fabricated aluminum 3D transmon superconducting qubits with these shadow masks and found coherence quality factors comparable to those fabricated with standard techniques.
The Distribution of High-Redshift Galaxy Colors: Line-of-Sight Variations in Neutral Hydrogen Absorption

We model, via Monte Carlo simulations, the distribution of observed U-B, B-V, and V-I galaxy colors in the range 1.75 3 galaxy luminosity function from color-selected samples is to measure the (observed) distribution of redshifts and intrinsic SED types and then consider the variation in color for each SED and redshift. A similar argument applies to the estimation of the luminosity function of color-selected, high-redshift QSOs.
A Systematic DNN Weight Pruning Framework Using Alternating Direction Method of Multipliers

Weight pruning methods for deep neural networks (DNNs) have been investigated recently, but prior work in this area is mainly heuristic, iterative pruning, thereby lacking guarantees on the weight reduction ratio and convergence time. To mitigate these limitations, we present a systematic weight pruning framework of DNNs using the alternating direction method of multipliers (ADMM). We first formulate the weight pruning problem of DNNs as a nonconvex optimization problem with combinatorial constraints specifying the sparsity requirements, and then adopt the ADMM framework for systematic weight pruning. By using ADMM, the original nonconvex optimization problem is decomposed into two subproblems that are solved iteratively. One of these subproblems can be solved using stochastic gradient descent, the other can be solved analytically. Besides, our method achieves a fast convergence rate.
Selection of quasi-stationary states in the Navier─Stokes equation on the torus

The two dimensional incompressible Navier–Stokes equation on with , periodic boundary conditions, and viscosity is considered. Bars and dipoles, two explicitly given quasi-stationary states of the system, evolve on the time scale and have been shown to play a key role in its long-time evolution. Of particular interest is the role that δ plays in selecting which of these two states is observed. Recent numerical studies suggest that, after a transient period of rapid decay of the high Fourier modes, the bar state will be selected if , while the dipole will be selected if . Our results support this claim and seek to mathematically formalize it. We consider the system in Fourier space, project it onto a center manifold consisting of the lowest eight Fourier modes, and use this as a model to study the selection of bars and dipoles. It is shown for this ODE model that the value of δ controls the behavior of the asymptotic ratio of the low modes, thus determining the likelihood of observing a bar state or dipole after an initial transient period. Moreover, in our model, for all , there is an initial time period in which the high modes decay at the rapid rate , while the low modes evolve at the slower rate. The results for the ODE model are proven using energy estimates and invariant manifolds and further supported by formal asymptotic expansions and numerics.
Conductivity and quasinormal modes in holographic theories

We show that in field theories with a holographic dual the retarded Green’s function of a conserved current can be represented as a convergent sum over the quasinormal modes. We find that the zero-frequency conductivity is related to the sum over quasinormal modes and their high-frequency asymptotics via a sum rule. We derive the asymptotics of the quasinormal mode frequencies and their residues using the phase-integral (WKB) approach and provide analytic insight into the existing numerical observations concerning the asymptotic behavior of the spectral densities.
Non-singular twisted S-branes from rotating branes

We show that rotating p-brane solutions admit an analytical continuation to become twisted Sp-branes. Although a rotating p-brane has a naked singularity for large angular momenta, the corresponding S-brane configuration is regular everywhere and exhibits a smooth bounce between two phases of Minkowski spacetime. If the foliating hyperbolic space of the transverse space is of even dimension, such as for the twisted SM5-brane, then for an appropriate choice of parameters the solution smoothly flows from a warped product of two-dimensional de Sitter spacetime, five-dimensional euclidean space and a hyperbolic 4-space in the infinite past to Minkowski spacetime in the infinite future. We also show that non-singular S-Kerr solutions can arise from higher-dimensional Kerr black holes, so long as all (all but one) angular momenta are non-vanishing for even (odd) dimensions.
Machine learning and serving of discrete field theories

A method for machine learning and serving of discrete field theories in physics is developed. The learning algorithm trains a discrete field theory from a set of observational data on a spacetime lattice, and the serving algorithm uses the learned discrete field theory to predict new observations of the field for new boundary and initial conditions. The approach of learning discrete field theories overcomes the difficulties associated with learning continuous theories by artificial intelligence. The serving algorithm of discrete field theories belongs to the family of structure-preserving geometric algorithms, which have been proven to be superior to the conventional algorithms based on discretization of differential equations. The effectiveness of the method and algorithms developed is demonstrated using the examples of nonlinear oscillations and the Kepler problem. In particular, the learning algorithm learns a discrete field theory from a set of data of planetary orbits similar to what Kepler inherited from Tycho Brahe in 1601, and the serving algorithm correctly predicts other planetary orbits, including parabolic and hyperbolic escaping orbits, of the solar system without learning or knowing Newton’s laws of motion and universal gravitation. The proposed algorithms are expected to be applicable when the effects of special relativity and general relativity are important.
Geometric Correction for Diffusive Expansion of Steady Neutron Transport Equation

We revisit the diffusive limit of a steady neutron transport equation in a two-dimensional unit disk with one-speed velocity. A classical theorem by Bensoussan et al. (Publ Res Inst Math Sci 15(1):53–157, 1979) states that its solution can be approximated in L ∞ by the leading order interior solution plus the Knudsen layer in the diffusive limit. In this paper, we construct a counterexample to this result via a different boundary layer expansion with geometric correction.
Limitations of Chemical Propulsion for Interstellar Escape from Habitable Zones Around Low-mass Stars

The habitable zones of low-mass stars are characterized by escape speeds that can be a few times higher than the Earth's orbit around the Sun. Owing to the exponential dependence of the required fuel mass on the terminal speed for chemical rockets, interstellar travel may not be easy for technological species inhabiting planets around M-dwarfs.
The time-scale for core collapse in spherical star clusters

Abstract The collapse time for a cluster of equal-mass stars is usually stated to be either 330 central relaxation times (trc) or 12-19 half-mass relaxation times (trh). But the first of these times applies only to the late stage of core collapse, and the second only to low-concentration clusters. To clarify how the time depends on the density profile, the Fokker-Planck equation is solved for the evolution of a variety of isotropic cluster models, including King models, models with power-law density cusps of ρ ∼ r−γ, and models with nuclei. The collapse times for King models vary considerably with the cluster concentration when expressed in units of trc or trh, but vary much less when expressed in units of trc divided by a dimensionless measure of the temperature gradient in the core. Models with cusps have larger temperature gradients and evolve faster than King models, but not all of them collapse: those with 0 Scott D. Tremaine
Honey from the Hives: A Theoretical and Computational Exploration of Combinatorial Hives

We begin with a review of combinatorial hives as introduced by Knutson and Tao, and focus on a conjecture by Danilov and Koshevoy for generating hives from Hermitian matrix pairs. We examine a prop...
Asymptotic syzygies of algebraic varieties

We study the asymptotic behavior of the syzygies of a smooth projective variety as the positivity of the embedding line bundle grows. The main result asserts that the syzygy modules are non-zero in almost all degrees allowed by Castelnuovo–Mumford regularity. We also give an effective statement for Veronese varieties that we conjecture to be optimal.
An effective field theory approach to two trapped particles

We discuss the problem of two particles interacting via short-range interactions within a harmonic-oscillator trap. The interactions are organized according to their number of derivatives and defined in truncated model spaces made from a bound-state basis. Leading-order (LO) interactions are iterated to all orders, while corrections are treated in perturbation theory. We show explicitly that next-to-LO and next-to-next-to-LO interactions improve convergence as the model space increases. In the large-model-space limit we regain results from a pseudopotential. Arbitrary scattering lengths are considered, as well as a generalization to include the non-vanishing range of the interaction.
On Shannon-Jaynes Entropy and Fisher Information

The fundamentals of the Maximum Entropy principle as a rule for assigning and updating probabilities are revisited. The Shannon‐Jaynes relative entropy is vindicated as the optimal criterion for use with an updating rule. A constructive rule is justified which assigns the probabilities least sensitive to coarse‐graining. The implications of these developments for interpreting physics laws as rules of inference upon incomplete information are briefly discussed.
When “Optimal Filtering” Isn’t

The so-called “optimal filter” analysis of a microcalorimeter's x-ray pulses is statistically optimal only if all pulses have the same shape, regardless of energy. However, the shapes of pulses from a nonlinear detector can and do depend on the pulse energy. A pulse-fitting procedure that we call “tangent filtering” accounts for the energy dependence of the shape and should, therefore, achieve superior energy resolution. We take a geometric view of the pulse-fitting problem and give expressions to predict how much the energy resolution stands to benefit from such a procedure. We also demonstrate the method with a case study of K-line fluorescence from several 3d transition metals. The method improves the resolution from 4.9 to 4.2 eV at the Cu K $\alpha$ line (8.0 keV).
Operation of a THGEM-based detector in low-pressure Helium

In view of a possible application as a charge-particle track readout for an Active Target Time Projection Chamber (AT-TPC), the operating properties of THick Gaseous Electron Multipliers (THGEM) in pure low-pressure Helium were investigated. This paper includes the effective gain dependence on pressure for different detector configurations (single-, double-, triple-cascade setup), long-term gain stability and energy resolution from tracks of 5.5 MeV alpha particles. Stable operational conditions and maximum detector gains of 104–107 have been achieved in pure Helium at pressure ranging from 100 torr up to 760 torr. Energy resolution of 6.65% (FWHM) for 690 keV of energy deposited by 5.5 MeV alpha particles at 350 torr was measured. The expected energy resolution for the full track is around 2.4% (FWHM). These results, together with the robustness of THGEM electrodes against spark damage, make THGEM structures highly competitive compared to other technologies considered for TPC applications in an active target operating with pure noble gases, requiring a high dynamic range and a wide operating pressure range down to few hundred torr.
Neutrino oscillation, finite self-mass and general Yang–Mills symmetry

The conservation of lepton number is assumed to be associated with a general Yang–Mills (gYM) symmetry. New transformations involve (Lorentz) vector gauge functions and characteristic phase functions, and they form a group. General Yang–Mills fields are associated with new fourth-order equations and linear potentials. Lepton self-masses turn out to be finite and proportional to the inverse of lepton masses, which implies that neutrinos should have nonzero masses. Thus, gYM symmetry could provide an understanding of neutrino oscillations and suggests that neutrinos with masses and very weak leptonic force may play a role in dark matter.
Global MHD Simulations of Accretion Disks in Cataclysmic Variables (CVs). II. The Relative Importance of MRI and Spiral Shocks

We perform global three-dimensional MHD simulations of unstratified accretion disks in cataclysmic variables (CVs). By including mass inflow via an accretion stream, we are able to evolve the disk to a steady state. We investigate the relative importance of spiral shocks and the magnetorotational instability (MRI) in driving angular momentum transport and how each depend on the geometry and strength of seed magnetic field and the Mach number of the disk (where Mach number is ratio of the azimuthal velocity and the sound speed of gas). We use a locally isothermal equation of state and adopt temperature profiles that are consistent with CV disk observations. Our results indicate that the relative importance of spiral shocks and MRI in driving angular momentum transport is controlled by the gas Mach number and the seed magnetic field strength. MRI and spiral shocks provide comparable efficiency of angular momentum transport when the disk Mach number is around 10 and the seed magnetic field has plasma $\beta=400$ (where $\beta$ is ratio of gas pressure and magnetic pressure). The MRI dominates whenever the seed field strength, or the disk Mach number, is increased. Among all of our simulations, the effective viscosity parameter $\alpha_{eff} \sim 0.016-0.1$ after MRI saturates and the disk reaches steady state. Larger values of $\alpha_{eff}$ are favored when the seed magnetic field has vertical components or the flow has stronger magnetization ($1/\beta$). Our models all indicate that the role of MRI in driving angular momentum transport thus mass accretion in CV disks is indispensable, especially in cool disks with weak spiral shocks.
The chromatic polynomials of signed Petersen graphs

Zaslavsky proved in 2012 that, up to switching isomorphism, there are six different signed Petersen graphs and that they could be told apart by their chromatic polynomials, by showing that the latter give distinct results when evaluated at 3. He conjectured that the six different signed Petersen graphs also have distinct zero-free chromatic polynomials, and that both types of chromatic polynomials have distinct evaluations at any positive integer. We developed and executed a computer program (running in SAGE) that efficiently determines the number of proper k-colorings for a given signed graph; our computations for the signed Petersen graphs confirm Zaslavsky’s conjecture. We also computed the chromatic polynomials of all signed complete graphs with up to five vertices. Graph coloring problems are ubiquitous in many areas within and outside of mathematics. We are interested in certain enumerative questions about coloring signed graphs. A signed graph Σ = (Γ, σ) consists of a graph Γ = (V,E) and a signature σ ∈ {±} . The underlying graph Γ may have multiple edges and, besides the usual links and loops, also half edges (with only one endpoint) and loose edges (no endpoints); the last are irrelevant for coloring questions, and so we assume in this paper that Σ has no loose edges. An unsigned graph can be realized by a signed graph all of whose edges are labelled with +. Signed graphs originated in the social sciences and have found applications also in biology, physics, computer science, and economics; see [4] for a comprehensive bibliography. The chromatic polynomial cΣ(2k+1) counts the proper k-colorings x ∈ {0,±1, . . . ,±k} , namely, those colorings that satisfy for any edge vw ∈ E xv 6= σvw xw and xv 6= 0 for any v ∈ V incident with some half edge. Zaslavsky [2] proved that cΣ(2k + 1) is indeed a polynomial in k. It comes with a companion, the zero-free chromatic polynomial cΣ(2k), which counts all proper k-colorings x ∈ {±1, . . . ,±k} . The Petersen graph has served as a reference point to many proposed results in graph theory. Considering signed Petersen graphs, Zaslavsky [5] showed that, while there are 215 ways to assign a signature to the fifteen edges, only six of these are different up to switching isomorphism (a notion that we will make precise below), depicted in Figure 1. (In our figures we represent a positive edge with a solid line and a negative edge with a dashed line.) In [5] Zaslavsky proved that these six signed Petersen graphs have distinct chromatic polynomials; thus they can be distinguished by this signed-graph invariant. He did not compute the chromatic polynomials but showed that they evaluate to distinct numbers at 3 [5, Table 9.2]. He conjectured Date: 18 December 2014. 2000 Mathematics Subject Classification. Primary 05C22; Secondary 05A15, 05C15.
Opacity Limit for Supermassive Protostars

We present a model for the evolution of supermassive protostars from their formation at until their growth to . To calculate the initial properties of the object in the optically thick regime, we follow two approaches: one based on idealized thermodynamic considerations, and another based on a more detailed one-zone model. Both methods derive a similar value of for the density of the object when opacity becomes important, i.e., the opacity limit. The subsequent evolution of the growing protostar is determined by the accretion of gas onto the object and can be described by a mass–radius relation of the form during the early stages, and of the form when internal luminosity becomes important. For the case of a supermassive protostar, this implies that the radius of the star grows from to during its evolution. Finally, we use this model to construct a subgrid recipe for accreting sink particles in numerical simulations. A prime ingredient thereof is a physically motivated prescription for the accretion radius and the effective temperature of the growing protostar embedded inside it. From the latter, we can conclude that photoionization feedback can be neglected until very late in the assembly process of the supermassive object.
Coherent and incoherent vortex flow states in crossed channels

We examine vortex flow states in periodic square pinning arrays with one row and one column of pinning sites removed to create an easy-flow crossed-channel geometry. When a drive is simultaneously applied along both major symmetry axes of the pinning array such that vortices move in both channels, a series of coherent-flow states develop in the channel intersection at rational ratios of the drive components in each symmetry direction when the vortices can cross the intersection without local collisions. The coherent-flow states are correlated with a series of anomalies in the velocity force curves, and in some cases can produce negative differential conductivity. The same general behavior could also be realized in other systems including colloids, particle traffic in microfluidic devices, or Wigner crystals in crossed one-dimensional channels.
Non-L–space integral homology $3$–spheres with no nice orderings

We give infinitely many examples of non-L–space irreducible integer homology 3–spheres whose fundamental groups do not have nontrivial PSL˜2(ℝ) representations.
Effect of Dot Size on Exciton Binding Energy and Electron–Hole Recombination Probability in CdSe Quantum Dots

Exciton binding energy and electron–hole recombination probability are presented as two important metrics for investigating effect of dot size on electron–hole interaction in CdSe quantum dots. Direct computation of electron–hole recombination probability is challenging because it requires an accurate mathematical description of the electron–hole wave function in the neighborhood of the electron–hole coalescence point. In this work, we address this challenge by solving the electron–hole Schrodinger equation using the electron–hole explicitly correlated Hartree–Fock (eh-XCHF) method. The calculations were performed for a series of CdSe clusters ranging from Cd20Se19 to Cd74608Se74837 that correspond to dot diameter range 1–20 nm. The calculated exciton binding energies and electron–hole recombination probabilities were found to decrease with increasing dot size. Both of these quantities were found to scale as Ddot–n with respect to the dot diameter D. One of the key insights from this study is that the ele...
The numerics of phase retrieval

Phase retrieval, i.e. the problem of recovering a function from the squared magnitude of its Fourier transform, arises in many applications, such as X-ray crystallography, diffraction imaging, optics, quantum mechanics and astronomy. This problem has confounded engineers, physicists, and mathematicians for many decades. Recently, phase retrieval has seen a resurgence in research activity, ignited by new imaging modalities and novel mathematical concepts. As our scientific experiments produce larger and larger datasets and we aim for faster and faster throughput, it is becoming increasingly important to study the involved numerical algorithms in a systematic and principled manner. Indeed, the past decade has witnessed a surge in the systematic study of computational algorithms for phase retrieval. In this paper we will review these recent advances from a numerical viewpoint.
Weaponizing Unicodes with Deep Learning -Identifying Homoglyphs with Weakly Labeled Data

Visually similar characters, or homoglyphs, can be used to perform social engineering attacks or to evade spam and plagiarism detectors. It is thus important to understand the capabilities of an attacker to identify homoglyphs – particularly ones that have not been previously spotted – and leverage them in attacks. We investigate a deep-learning model using embedding learning, transfer learning, and augmentation to determine the visual similarity of characters and thereby identify potential homoglyphs. Our approach uniquely takes advantage of weak labels that arise from the fact that most characters are not homoglyphs. Our model drastically outperforms the Normal-ized Compression Distance approach on pairwise homoglyph identification, for which we achieve an average precision of 0.97. We also present the first attempt at clustering homoglyphs into sets of equivalence classes, which is more efficient than pairwise information for security practitioners to quickly lookup homoglyphs or to normalize confusable string encodings. To measure clustering performance, we propose a metric (mBIOU) building on the classic Intersection-Over-Union (IOU) metric. Our clustering method achieves 0.592 mBIOU, compared to 0.430 for the naive baseline. We also use our model to predict over 8,000 previously unknown homoglyphs, and find good early indications that many of these may be true positives. Source code and list of predicted homoglyphs are uploaded to Github: https://github.com/PerryXDeng/weaponizing_unicode
TEASER: Fast and Certifiable Point Cloud Registration

We propose the first fast and certifiable algorithm for the registration of two sets of three-dimensional (3-D) points in the presence of large amounts of outlier correspondences. A certifiable algorithm is one that attempts to solve an intractable optimization problem (e.g., robust estimation with outliers) and provides readily checkable conditions to verify if the returned solution is optimal (e.g., if the algorithm produced the most accurate estimate in the face of outliers) or bound its suboptimality or accuracy. Toward this goal, we first reformulate the registration problem using a truncated least squares (TLS) cost that makes the estimation insensitive to a large fraction of spurious correspondences. Then, we provide a general graph-theoretic framework to decouple scale, rotation, and translation estimation, which allows solving in cascade for the three transformations. Despite the fact that each subproblem (scale, rotation, and translation estimation) is still nonconvex and combinatorial in nature, we show that 1) TLS scale and (component-wise) translation estimation can be solved in polynomial time via an adaptive voting scheme, 2) TLS rotation estimation can be relaxed to a semidefinite program (SDP) and the relaxation is tight, even in the presence of extreme outlier rates, and 3) the graph-theoretic framework allows drastic pruning of outliers by finding the maximum clique. We name the resulting algorithm TEASER ( Truncated least squares Estimation And SEmidefinite Relaxation ). While solving large SDP relaxations is typically slow, we develop a second fast and certifiable algorithm, named TEASER++, that uses graduated nonconvexity to solve the rotation subproblem and leverages Douglas-Rachford Splitting to efficiently certify global optimality. For both algorithms, we provide theoretical bounds on the estimation errors, which are the first of their kind for robust registration problems. Moreover, we test their performance on standard benchmarks, object detection datasets, and the 3DMatch scan matching dataset, and show that 1) both algorithms dominate the state-of-the-art (e.g., RANSAC, branch-&-bound, heuristics) and are robust to more than $\text{99}\%$ outliers when the scale is known, 2) TEASER++ can run in milliseconds and it is currently the fastest robust registration algorithm, and 3) TEASER++ is so robust it can also solve problems without correspondences (e.g., hypothesizing all-to-all correspondences), where it largely outperforms ICP and it is more accurate than Go-ICP while being orders of magnitude faster. We release a fast open-source C++ implementation of TEASER++.
Impact of Gender on Doctor-Patient Communication and Emotion: Exploratory Analysis

Doctor-patient communication is one of the essential precursors of patient-centered care. The quality of this communication is influenced by several factors, including providers' communication style and the use of existing technologies. In our previous studies, we measured the impact of health information technology on doctor-patient communication. In this study, we used sentiment analysis to understand the impact of doctor-patient gender dyads on verbal communication. The findings showed a noticeable difference in the communication pattern between the same (concordance) and opposite gender dyads (discordance). The findings of this study also indicate that male doctors tend to talk more and in detail with their patients ( $p= 0.01$ for gender concordance; $p=0.01$ during gender discordance) than female doctors did with their patients ( $p=0.33$ for gender concordance; $p=0.41$ during gender discordance), irrespective of doctor-patient gender dyads. No significant differences were observed in doctor-patient sentiments and emotions. However, we observed more trust in gender concordance (20.9% & 17.6% of the time). In contrast, gender discordance resulted in more sadness (15.5% & 19.8% of the time), anticipation (17.3%), and joy (16.1% of the time). In conclusion, our study indicates that gender influences doctor-patient verbal communication. Further research with larger sample size is required to thoroughly understand the role of gender in overall healthcare communication.
Formal Verification of Arithmetic RTL: Translating Verilog to C++ to ACL2.

We present a methodology for formal verification of arithmetic RTL designs that combines sequential logic equivalence checking with interactive theorem proving. An intermediate model of a Verilog module is hand-coded in Restricted Algorithmic C (RAC), a primitive subset of C augmented by the integer and fixed-point register class templates of Algorithmic C. The model is designed to be as abstract and compact as possible, but sufficiently faithful to the RTL to allow efficient equivalence checking with a commercial tool. It is then automatically translated to the logic of ACL2, enabling a mechanically checked proof of correctness with respect to a formal architectural specification. In this paper, we describe the RAC language, the translation process, and some techniques that facilitate formal analysis of the resulting ACL2 code.
Resilient Control: Compromising to Adapt

In optimal control problems, disturbances are typically dealt with using robust solutions, such as ${\mathcal{H}_\infty }$ or tube model predictive control, that plan control actions feasible for the worst-case disturbance. Yet, planning for every contingency can lead to over-conservative, poorly performing solutions or even, in extreme cases, to infeasibility. Resilience addresses these shortcomings by adapting the underlying control problem, e.g., by relaxing its specifications, to obtain a feasible, possibly still valuable trajectory. Despite their different aspects, robustness and resilience are often conflated in the context of dynamical systems and control. The goal of this paper is to formalize, in the context of optimal control, the concept of resilience understood as above, i.e., in terms of adaptation. To do so, we introduce a resilient formulation of optimal control by allowing disruption-dependent modifications of the requirements that induce the desired resilient behavior. We then propose a framework to design these behaviors automatically by trading off control performance and requirement violations. We analyze this resilience-by-compromise method to obtain inverse optimality results and quantify the effect of disturbances on the induced requirement relaxations. By proving that robustness and resilience optimize different objectives, we show that these are in fact distinct system properties. We conclude by illustrating the effect of resilience in different control problems.
On Improving Hotspot Detection Through Synthetic Pattern-Based Database Enhancement

Design hotspots are layout patterns which may cause defects due to complex design and process interactions. Several machine learning and pattern matching-based methods have been proposed to identify and correct them early during design stages. However, almost all of them suffer from high false-alarm rates, mainly because they are oblivious to the root causes of hotspots. In this work, we seek to address this limitation by using a novel database enhancement approach through synthetic pattern generation based on a carefully crafted design of experiments. We evaluate the effectiveness of the proposed method using industry-standard tools and designs and demonstrate more than $3\times $ reduction in classification error in comparison to the state-of-the-art.
Moving from Design to Strategy: The Four Roles of Design-Led Strategy Consulting

Design professionals have increasingly sought to provide clients not only with design solutions to fit existing plans but also with strategic advice for future opportunities. How can designers serve such a role? This study was based on field research with London-based designers and identified four roles they played: that of strategy visualizer, core competence prospector, market exploiter, and process provider. Each role is described, and the implications for successful collaboration on strategic efforts are discussed.
Simplification and Saving

The daunting complexity of important financial decisions can lead to procrastination. We evaluate a low-cost intervention that substantially simplifies the retirement savings plan participation decision. Individuals received an opportunity to enroll in a retirement savings plan at a pre-selected contribution rate and asset allocation, allowing them to collapse a multidimensional problem into a binary choice between the status quo and the pre-selected alternative. The intervention increases plan enrollment rates by 10 to 20 percentage points. We find that a similar intervention can be used to increase contribution rates among employees who are already participating in a savings plan.
Originalism vs. Precedent: An Evolutionary Perspective

This essay asks whether originalist interpretive methods, on average, are likely to produce better or worse rules than nonoriginalist methods. By "originalist" I mean to refer to any text-based decision-making technique that permits its user to ignore intervening learning and rely on some aspect of the original text whenever the two conflict. I am not asking about legitimacy; originalist methods may well produce more legitimate outcomes. My focus is rather on the merits of the resulting rules themselves. The approach the essay takes is to describe how cultures learn and, on the basis of that description, assert that such learning is itself generally adaptive. If cultures learn and such learning is adaptive, then any decision-making procedure that systematically ignores such learning is problematic.
PROPORTIONALITY: THE STRUGGLE FOR BALANCE IN U.S. IMMIGRATION POLICY†

The current debate regarding state and local enforcement of national immigration laws is not primarily a struggle to achieve a more perfect balance in state-federal relations. Rather, it is an underlying, substantive disagreement about the content of our immigration policies.Another way to describe this more fundamental disagreement is as one about proportionality – whether the sanction of removal fits the offense for which it is meted out. Proportionality is a concept with ancient roots in Anglo-American law, and is reflected in numerous common law rules and constitutional provisions. In the United States, judicial enforcement of the constitutional command of proportionality tends to operate as a limiting principle, restricting government action only in extreme cases. The principle may have useful application in the immigration context. Removal orders should be subject to proportionality review by courts, both on a case-by-case basis and categorically. This is so under the Eighth Amendment, at least in cases where a removal order is the result of a criminal conviction. This is also so under the Fifth Amendment Due Process Clause, even where deportation is not the result of a criminal conviction, because a removal order is a punitive sanction that mandates departure and also bars lawful return for a period of years. Respondents in removal proceedings might argue that their removal – whether because relief has been denied, or because no relief is available at all – would violate the constitutional requirement of proportionality. Courts will honor these principles, and Supreme Court precedent, by adjudicating both case-by-case and categorical proportionality challenges. In appropriate cases, courts should find that removal is so grossly disproportionate to the gravity of the offense as to be forbidden by the Constitution.
Intertemporal price–quality discrimination and the Coase conjecture

Abstract We examine time-consistent intertemporal price–quality discrimination by a durable goods monopolist, when there are a continuum of buyer demand-intensities with respect to product quality, and it is profitable for the monopolist to trade with the marginal buyer-type (i.e., the “gap” case). We show that along every subgame perfect equilibrium path, with probability 1, prices and qualities decline over time, and the market is completely and monotonically depleted according to buyer-type in a finite number of offers. But, unlike the fixed quality literature, the monopolist may randomize over price–quality offers along the equilibrium path. We also show that the Coase conjecture continues to be valid here, but in a form that is significantly different from the usual formulation. In the limit, as the time between offers evaporates, the monopolist makes a continuum of offers and perfectly screens the market. However, he effectively cannot price-discriminate, because the equilibrium profits converge to the complete “pooling” profits that would be made if the entire market had the marginal buyer-type’s valuation.
Acquiring Information through Peers

We study information acquisition from peers when agents’ actions balance adaptation and coordination motives. Agents acquire information personally and may obtain additional infor- mation by connecting to other agents. Although equally informative regarding adaptation, the source’s relative position in the information structure is relevant to form expectations about actions of other players. In our setting, information sources are not perfectly substitutable, and the information of an “opinion maker”—an agent whose information is more public—is more informative of how others act. We show that, when players choose their connections, (i) it is always preferable to connect to opinion makers, and (ii) opinion makers have less incentives to form links. These two results characterize the endogenous shape of the network: Any strict equilibrium of the network formation game generates a hierarchical information structure. Fur- thermore, if the marginal cost of acquiring information is increasing, the information structure is “core-periphery”. We take advantage of the simplicity of the equilibrium information struc- ture to provide two applications. First, we use data on earnings-per-share forecasts to provide an example of how much of the aggregate volatility of forecast can the information structure account for. Second, we focus on the origins of leadership: how individual characteristics influence the role of the agent in the information structure.
Optimal Savings Distortions with Recursive Preferences

Abstract This paper derives an intertemporal optimality condition for economies with private information, focusing on a class of recursive preferences. By comparing it to the situation where agents can freely save in a risk-free asset market, we derive the optimal savings distortions necessary for constrained optimality. Our recursive preferences are homogeneous and satisfy a balanced-growth condition, while allowing us to separate the role of risk aversion and intertemporal elasticity of substitution. We perform some quantitative exercises that disentangle the respective roles played by these two parameters in optimal distortions and the implied welfare gains.
Involved Appellate Judging

What happens when the parties to an appeal simply miss the point? This article explores the extent to which an appellate court should involve itself in the process by adding to or refining the arguments the parties have made to support the issues they have properly raised. It examines whether the role of an appellate court is simply to decide among the arguments explicitly set before it, or to reflect on the issue the parties have brought to the court and to reach the best resolution of that issue in light of their own contribution to the analysis. Furthermore, the article looks at the extent to which the court must or should involve the parties - the extent to which they must afford the parties an opportunity to engage with the new argument or reasoning before issuing an opinion - in the event that the court does come up with its own alternative arguments or reasoning on a particular issue. It ultimately concludes that, above all else, these questions require further open and deliberate examination by the appellate courts that deal with them on a regular basis. It appears that judges may currently engage in this kind of involved judging without making it explicit, and/or without explaining why they are justified in so involving themselves. This article suggests that judges serve in some respects as trustees or custodians of the law, and therefore have an active role to play in directing individual cases to the best and clearest conclusions. Until any further self-examination by appellate courts should occur, the article proposes that judges, as trustees of the law, should at least be strongly encouraged to be more involved, by using their discretion, to improve the state of the common law by implementing what they see as the most correct reasoning.
When Did Education Become a Civil Right? An Assessment of State Constitutional Provisions for Education 1776-1900

Today, education is perhaps the most important function of state and local governments. Compulsory school attendance laws and the great expenditures for education both demonstrate our recognition of the importance of education to our democratic society. It is required in the performance of our most basic public responsibilities, even service in the armed forces. It is the very foundation of good citizenship. Today it is a principal instrument in awakening the child to cultural values, in preparing him for later professional training, and in helping him to adjust normally to his environment. In these days, it is doubtful that any child may reasonably be expected to succeed in life if he is denied the opportunity of an education.2
Insurance and the Law

This article is a revision of the previous edition article by T. Baker, volume 11, pp. 7587–7591, © 2001, Elsevier Ltd.
What Did the Framers Know, and When Did They Know It? Fictional Originalism in Crawford v. Washington

Justice Scalia made two originalist claims about the application of the Sixth Amendment Confrontation Clause to hearsay evidence in his opinion for the Court in Crawford v. Washington, 541 U.S. 36 (2004). He interpreted the framing-era content of the confrontation right to include a cross-examination rule under which testimonial hearsay statements were admissible only if the declarant was unavailable and the defendant had had a prior opportunity to cross-examine. However, he interpreted the scope of the framing-era right narrowly by asserting that the Framers were concerned only with regulating testimonial hearsay but did not intend to prohibit the admissibility of casual, nontestimonial hearsay. This article argues that neither of these claims was historically sound. The primary historical issue regarding the cross-examination rule involved the admissibility in a felony criminal trial of the written record of a post-arrest examination of a sworn witness taken by a justice of the peace under the Marian statutes. Justice Scalia recognized that such examinations were once admissible provided only that the witness had become genuinely unavailable (for example, had died prior to the trial), but asserted that a 1696 case had made cross-examination a condition for admissibility, and also asserted that three English cases decided in 1787, 1789, and 1791 had removed any doubt as to the cross-examination requirement. This article argues that the 1696 case dealt only with a misdemeanor and thus was inapplicable to the felony prosecutions to which the Marian statutes applied, and that none of the three later cases were published in London early enough to have come to the Framers' attention when the Bill of Rights was framed in 1789. Instead, it documents that the treatises and justice of the peace manuals available in framing-era America simply stated that Marian witness examinations were admissible if the witness had become genuinely unavailable. Thus, Crawford's cross-examination rule claim was prochronistic; although such a rule was adopted in England and America after the framing, it was not a part of the Framers' understanding. The salient feature of Justice Scalia's originalist claim that the scope of the confrontation right was limited to only testimonial but not nontestimonial hearsay is that he offered no actual historical evidence of any such distinction. Rather, as Chief Justice Rehnquist noted in his concurring opinion in Crawford, the historical rule was that hearsay is no evidence. Thus, the Framers had no occasion to consider the application of the confrontation right to unsworn hearsay, because they expected that such hearsay would not be admissible in any event. The article concludes by arguing that the fictional history in Crawford's rationale provides further evidence that the distance between framing-era and contemporary doctrine and institutions is so great that originalism is not a feasible approach to constitutional interpretation.
PARTICIPANT REACTION AND THE PERFORMANCE OF FUNDS OFFERED BY 401(K) PLANS

Abstract This is the first study to examine both how well plan administrators select funds for 401(k) plans and how participants react to plan administrator decisions. We find that, on average, administrators select funds that outperform randomly selected funds of the same type although they do not outperform index funds of the same type. When administrators change offerings, they choose funds that did well in the past, but, after the change, added funds do no better than dropped funds. Plan participants in aggregate change their allocation decisions in a way that accentuates the changes in allocation caused by returns. The change in allocation due to the investment of new money and interfund transfers is about the same size, and in the same direction, as the change due to returns. Participant allocations in aggregate do no better than naive allocation rules, such as equal investment in each offering.