Showing papers on "Naturalness published in 2016"

On the naturalness of software

Abstract: Natural languages like English are rich, complex, and powerful. The highly creative and graceful use of languages like English and Tamil, by masters like Shakespeare and Avvaiyar, can certainly delight and inspire. But in practice, given cognitive constraints and the exigencies of daily life, most human utterances are far simpler and much more repetitive and predictable. In fact, these utterances can be very usefully modeled using modern statistical methods. This fact has led to the phenomenal success of statistical approaches to speech recognition, natural language translation, question-answering, and text mining and comprehension.We begin with the conjecture that most software is also natural, in the sense that it is created by humans at work, with all the attendant constraints and limitations---and thus, like natural language, it is also likely to be repetitive and predictable. We then proceed to ask whether (a) code can be usefully modeled by statistical language models and (b) such models can be leveraged to support software engineers. Using the widely adopted n-gram model, we provide empirical evidence supportive of a positive answer to both these questions. We show that code is also very regular, and, in fact, even more so than natural languages. As an example use of the model, we have developed a simple code completion engine for Java that, despite its simplicity, already improves Eclipse's completion capability. We conclude the paper by laying out a vision for future research in this area.

On the "naturalness" of buggy code

Abstract: Real software, the kind working programmers produce by the kLOC to solve real-world problems, tends to be “natural”, like speech or natural language; it tends to be highly repetitive and predictable. Researchers have captured this naturalness of software through statistical models and used them to good effect in suggestion engines, porting tools, coding standards checkers, and idiom miners. This suggests that code that appears improbable, or surprising, to a good statistical language model is “unnatural” in some sense, and thus possibly suspicious. In this paper, we investigate this hypothesis. We consider a large corpus of bug fix commits (ca. 7,139), from 10 different Java projects, and focus on its language statistics, evaluating the naturalness of buggy code and the corresponding fixes. We find that code with bugs tends to be more entropic (i.e. unnatural), becoming less so as bugs are fixed. Ordering files for inspection by their average entropy yields cost-effectiveness scores comparable to popular defect prediction methods. At a finer granularity, focusing on highly entropic lines is similar in cost-effectiveness to some well-known static bug finders (PMD, FindBugs) and or- dering warnings from these bug finders using an entropy measure improves the cost-effectiveness of inspecting code implicated in warnings. This suggests that entropy may be a valid, simple way to complement the effectiveness of PMD or FindBugs, and that search-based bug-fixing methods may benefit from using entropy both for fault-localization and searching for fixes.

See-saw composite Higgs model at the LHC: Linking naturalness to the 750 GeV diphoton resonance

Abstract: We explore the possibility of explaining the recent ∼750 GeV excesses observed by ATLAS and CMS in the γγ spectrum in the context of a compelling theory of naturalness. The potential spin-zero resonance responsible for the excesses also requires the existence of new heavy charged states. We show that both such features are naturally realized in a see-saw composite Higgs model for electroweak symmetry breaking, where the new pseudo-Goldstone bosons are expected to be comparatively heavier than the Standard Model Higgs, and the new fermions have masses in the TeV range. If confirmed, the existence of this new resonance could be the first stone in the construction of a new theory of naturalness.

Cosmological Signals of a Mirror Twin Higgs

Abstract: We investigate the cosmology of the minimal model of neutral naturalness, the mirror Twin Higgs. The softly-broken mirror symmetry relating the Standard Model to its twin counterpart leads to significant dark radiation in tension with BBN and CMB observations. We quantify this tension and illustrate how it can be mitigated in several simple scenarios that alter the relative energy densities of the two sectors while respecting the softly-broken mirror symmetry. In particular, we consider both the out-of-equilibrium decay of a new scalar as well as reheating in a toy model of twinned inflation, Twinflation. In both cases the dilution of energy density in the twin sector does not merely reconcile the existence of a mirror Twin Higgs with cosmological constraints, but predicts contributions to cosmological observables that may be probed in current and future CMB experiments. This raises the prospect of discovering evidence of neutral naturalness through cosmology rather than colliders.

Towards a No-Lose Theorem for Naturalness

Abstract: We derive a phenomenological no-lose theorem for naturalness up to the TeV scale, which applies when quantum corrections to the Higgs mass from top quarks are canceled by perturbative beyond Standard Model (BSM) particles (top partners) of similar multiplicity due to to some symmetry. Null results from LHC searches already seem to disfavor such partners if they are colored. Any partners with SM charges and ∼TeV masses will be exhaustively probed by the LHC and a future 100 TeV collider. Therefore, we focus on neutral top partners. While these arise in twin Higgs theories, we analyze neutral top partners as model-independently as possible using effective field theory and simplified model methods. We classify all perturbative neutral top partner structures in order to compute their irreducible low-energy signatures at proposed future lepton and hadron colliders, as well as the irreducible tunings suffered in each scenario. Central to our theorem is the assumption that SM-charged BSM states appear in the UV completion of neutral naturalness, which is the case in all known examples. Direct production at the 100 TeV collider then allows this scale to be probed at the ∼10 TeV level. We find that proposed future colliders probe any such scenario of naturalness with tuning of 10% or better. This provides very strong model-independent motivation for both new lepton and hadron colliders, which in tandem act as discovery machines for general naturalness. We put our results in context by discussing other possibilities for naturalness, including “swarms” of top partners, inherently nonperturbative or exotic physics, or theories without SM-charged states in the UV completion. Realizing a concrete scenario which avoids our arguments while still lacking experimental signatures remains an open model-building challenge.

Late-time cosmic acceleration: ABCD of dark energy and modified theories of gravity

Abstract: We briefly review the problems and prospects of the standard lore of dark energy. We have shown that scalar fields, in principle, cannot address the cosmological constant problem. Indeed, a fundamental scalar field is faced with a similar problem dubbed naturalness. In order to keep the discussion pedagogical, aimed at a wider audience, we have avoided technical complications in several places and resorted to heuristic arguments based on physical perceptions. We presented underlying ideas of modified theories based upon chameleon mechanism and Vainshtein screening. We have given a lucid illustration of recently investigated ghost-free nonlinear massive gravity. Again, we have sacrificed rigor and confined to the basic ideas that led to the formulation of the theory. The review ends with a brief discussion on the difficulties of the theory applied to cosmology.

Preference for naturalness of European organic consumers: First evidence of an attitude-liking gap

Abstract: Purpose The purpose of this paper is to provide insights into European organic consumers’ attitudes towards natural food and in their sensory preference for it. It explores whether there is any evidence for a latent dimension that represents consumers’ attitudes towards naturalness and which aspects can be assigned to this dimension. However, the main scope is to investigate whether attitudes towards naturalness are able to predict the liking of natural food. Design/methodology/approach Sensory tests of strawberry yoghurt are combined with consumer information obtained by means of a standardised questionnaire. About 1,800 organic consumers from France, Germany, Italy, the Netherlands, Poland and Switzerland were asked to blindly test two strawberry yoghurt samples that differed only in their absence/presence of an aroma additive. Findings On average, the consumers revealed a positive attitude towards natural food, but a negative sensory preference for the more natural yoghurt sample. Correlations between these two variables indicate that for most countries one cannot conclude that more naturalness-oriented consumers actually prefer the taste of more naturally flavoured yoghurts. This finding is interpreted as an attitude-liking gap. Research limitations/implications More research is necessary in order to clarify the reasons for the attitude-liking gap, since the authors can only speculate about these. Also, suitable data are needed to confirm the assumption made here that the naturalness of strawberry yoghurt can be determined by the degree of flavour intensity, especially against the background that the sensory skills of consumers are usually weak. Originality/value No attempt has been undertaken so far to test the claim that natural food products taste better and whether consumers with a positive attitude towards naturalness actually prefer the taste of a natural product over the taste of a more processed one. The present study attempts to fill this gap by exploring the preference for naturalness in a cross-national context.

The Multiverse and Particle Physics

Abstract: The possibility of fundamental theories with very many ground states, each with different physical parameters, changes the way that we approach the major questions of particle physics. Most importantly, it raises the possibility that these different parameters could be realized in different domains in the larger universe. In this review, I survey the motivations for the multiverse and the impact of the idea of the multiverse on the search for new physics beyond the Standard Model.

Counting Vacua in Random Landscapes

Abstract: It is speculated that the correct theory of fundamental physics includes a large landscape of states, which can be described as a potential which is a function of N scalar fields and some number of discrete variables. The properties of such a landscape are crucial in determining key cosmological parameters including the dark energy density, the stability of the vacuum, the naturalness of inflation and the properties of the resulting perturbations, and the likelihood of bubble nucleation events. We codify an approach to landscape cosmology based on specifications of the overall form of the landscape potential and illustrate this approach with a detailed analysis of the properties of N-dimensional Gaussian random landscapes. We clarify the correlations between the different matrix elements of the Hessian at the stationary points of the potential. We show that these potentials generically contain a large number of minima. More generally, these results elucidate how random function theory is of central importance to this approach to landscape cosmology, yielding results that differ substantially from those obtained by treating the matrix elements of the Hessian as independent random variables.

Beyond the Standard Model

Abstract: We introduce aspects of physics beyond the Standard Model focusing on supersymmetry, extra dimensions, and a composite Higgs as solutions to the Hierarchy problem. Lectures given at the 2013 European School of High Energy Physics, Paradfurd˝ o, Hungary, 5 ‐ 18 June 2013. This document is based on lectures by C.C. on physics beyond the Standard Model at the 2013 European School of High-Energy Physics. We present a pedagogical introduction to supersymmetry, extra dimensions, and composite Higgs. We provide references to useful review literature and refer to those for more complete citations to original papers on these topics. We apologize for any omissions in our citations or choice of topics.

A Hierarchical Predictor of Synthetic Speech Naturalness Using Neural Networks

Abstract: A problem when developing and tuning speech synthesis systems is that there is no well-established method of automatically rating the quality of the synthetic speech. This research attempts to obtain a new automated measure which is trained on the result of large-scale subjective evaluations employing many human listeners, i.e., the Blizzard Challenge. To exploit the data, we experiment with linear regression, feed-forward and convolutional neural network models, and combinations of them to regress from synthetic speech to the perceptual scores obtained from listeners. The biggest improvements were seen when combining stimulusand system-level predictions.

Usefulness, localizability, humanness, and language-benefit: additional evaluation criteria for natural language dialogue systems

Abstract: Human---computer dialogue systems interact with human users using natural language. We used the ALICE/AIML chatbot architecture as a platform to develop a range of chatbots covering different languages, genres, text-types, and user-groups, to illustrate qualitative aspects of natural language dialogue system evaluation. We present some of the different evaluation techniques used in natural language dialogue systems, including black box and glass box, comparative, quantitative, and qualitative evaluation. Four aspects of NLP dialogue system evaluation are often overlooked: "usefulness" in terms of a user's qualitative needs, "localizability" to new genres and languages, "humanness" or "naturalness" compared to human---human dialogues, and "language benefit" compared to alternative interfaces. We illustrated these aspects with respect to our work on machine-learnt chatbot dialogue systems; we believe these aspects are worthwhile in impressing potential new users and customers.

Privileging Naturals Over Strivers The Costs of the Naturalness Bias

Abstract: A preference for "naturals" over "strivers" in performance judgments was investigated to test whether the effect is generalizable across domains, as well as to ascertain any costs imposed on decision quality by favoring naturals. Despite being presented with entrepreneurs equal in achievement, participants judged the natural and his business proposal to be superior to the striver and his proposal on multiple dimensions of performance and success (Study 1a and Study 1b). These findings were extended in Study 2, which quantified the costs of the naturalness bias using conjoint analysis to measure specific decision tradeoffs. Together, these three studies show that people tend to pass over better-qualified individuals in favor of apparent naturals.

Higgs naturalness and the scalar boson proliferation instability problem

Abstract: Sensitivity to the square of the cutoff scale of quantum corrections of the Higgs boson mass self-energy has led many authors to conclude that the Higgs theory suffers from a naturalness or fine-tuning problem. However, speculative new physics ideas to solve this problem have not manifested themselves yet at high-energy colliders, such as the Large Hadron Collider at CERN. For this reason, the role of naturalness as a guide to theory model-building is being severely questioned. Most attacks suggest that one should not resort to arguments involving gravity, which is a much less understood quantum field theory. Another line of attack is against the assumption that there exists a multitude of additional heavy states specifically charged under the Standard Model gauge symmetries. Nevertheless, if we give ground on both of these assaults on naturalness, what remains is a naturalness concern over the prospect of numerous additional spin-zero scalar states in nature. The proliferation of heavy scalars generically destabilizes the Higgs boson mass, raising it to the highest and most remote scalar mass values in nature, thus straining the legitimacy of the Standard Model. The copious use of extra scalars in theory model building, from explaining flavor physics to providing an inflationary potential and more, and the generic expectation of extra scalar bosons in nature argues for the proliferation instability problem being the central concern for naturalness of the Standard Model. Some approaches to solving this problem are presented.

Entrainment in Pedestrian Direction Giving: How Many Kinds of Entrainment?

Abstract: Human conversants in dialog adjust their behavior to their conversational partner in many ways. In terms of language use, they adapt to their partners both lexically and syntactically, by using the same referring expressions or sentence structure. In this paper, we describe a natural language generator personage-primed, which can produce utterances entrained to a range of utterance features used in prior utterances by a human user, and represented in the discourse context. Personage-primed can entrain to the user’s referring expressions, tense-modality selection, verb and noun lexical selection, hedge and cue word choice, and syntactic template selection, or any combination of these. To our knowledge, there is no other NLG engine that can dynamically generate all these types of entrainment in any utterance. We report an experiment testing all possible combinations of entrainment in a particular discourse context in order to test whether some types of entrainment are preferred, either because they make the utterance more natural, or because humans perceive the system as more friendly. Our experimental results suggest that human judgements of naturalness are distinct from friendliness: entraining on a user’s hedges increase perceptions of friendliness while reducing naturalness, while entraining on user’s referring expressions, syntactic template selection and tense/modal choices increase perceptions of both naturalness and friendliness.

Ecological Nature: A Non-Dualistic Concept for Rethinking Humankind's Place in the World

Abstract: This paper puts forward a concept of naturalness as an alternative to the wilderness concept, which has been criticized for problematically situating human beings outside the natural world and thus conceptually foreclosing the possibility of humans living in harmony with nature. After examining and finding inadequate two concepts of naturalness dominant in the work of environmental ethicists, namely the natural as opposed to the supernatural and the natural as opposed to the anthropogenic, the paper delineates a concept of ecological naturalness, which links naturalness to ecological normality and ecosystem health. Tracing the historical roots of this concept back to classical Aristotelian philosophy, the paper shows that a contemporary ecological version of it actually underpins the intuitive views of many current-day environmentalists and ecologists. The paper concludes that the concept of ecological naturalness is better suited than the wilderness concept to support efforts at enabling humans to inhabit the earth’s ecosystems in ecologically sustainable ways.

Naturalness index for a tone-mapped high dynamic range image.

Abstract: High dynamic range (HDR) images can only be backward-compatible with existing low dynamic range (LDR) imaging systems after being processed by tone-mapping operators. Hence, the quality assessment (QA) of tone-mapped HDR images has become an important and challenging issue in HDR imaging research. In this paper, we propose a naturalness index for a tone-mapped image to predict its quality. First, we extract the statistical features of the tone-mapped image's luminance value and use it to evaluate the brightness naturalness with no reference information. Meanwhile, we use perceptive color, image contrast, and detail information to represent the image content and predict their naturalness qualities, respectively. Then, the four components of the naturalness qualities are combined to yield the overall naturalness quality of the tone-mapped image. Experimental results on a publicly available database demonstrated that, in comparison with a traditional LDR image QA method and a leading tone-mapped image QA method, the proposed method has better performance in evaluating a tone-mapped image's quality.

Dark Matter and the Higgs in Natural SUSY

Abstract: Null results from dark matter (DM) direct detection experiments and the 125 GeV Higgs both pose serious challenges to minimal supersymmetry. In this paper, we propose a simple extension of the MSSM that economically solves both problems: a "dark sector" consisting of a singlet and a pair of $SU(2)$ doublets. Loops of the dark sector fields help lift the Higgs mass to 125 GeV consistent with naturalness, while the lightest fermion in the dark sector can be viable thermal relic DM, provided that it is mostly singlet. The DM relic abundance is controlled by s-wave annihilation to tops and Higgsinos, leading to a tight relation between the relic abundance and the spin-dependent direct detection cross section. As a result, the model will be fully probed by the next generation of direct detection experiments. Finally we discuss the discovery potential at LHC Run II.

Improving naturalness in gauge mediation with nonunified messenger sectors

Abstract: We study models of gauge-mediated supersymmetry breaking with messengers that do not belong to complete representations of grand-unified gauge groups. We show that certain setups characterized by a heavy Wino can greatly improve the fine-tuning with respect to models with unified messengers, such as minimal gauge mediation. The typical models with low-tuning feature multi-TeV superparticles, with the exception of the Higgsinos and possibly Bino and right-handed sleptons. As a consequence, the absence of signals for supersymmetry at the LHC is trivially accommodated in our framework. On the other hand, testing these models will be challenging at the LHC. We finally show that the gravitino can be a consistent candidate for cold dark matter, provided a rather low reheating temperature, if a standard thermal history of the Universe is assumed.

Low-mass neutralino dark matter in supergravity scenarios: Phenomenology and naturalness

Abstract: The latest experimental results from the LHC and dark matter (DM) searches suggest that the parameter space allowed in supersymmetric theories is subject to strong reductions. These bounds are especially constraining for scenarios entailing light DM particles. Previous studies have shown that light neutralino DM in the Minimal Supersymmetric Standard Model (MSSM), with parameters defined at the electroweak scale, is still viable when the low energy spectrum of the model features light sleptons, in which case, the relic density constraint can be fulfilled. In view of this, we have investigated the viability of light neutralinos as DM candidates in the MSSM, with parameters defined at the grand unification scale. We have analysed the optimal choices of non-universalities in the soft supersymmetry-breaking parameters for both, gauginos and scalars, in order to avoid the stringent experimental constraints. We show that light neutralinos, with a mass as low as 25 GeV, are viable in supergravity scenarios if the gaugino mass parameters at high energy are very non universal, while the scalar masses can remain of the same order. These scenarios typically predict a very small cross section of neutralinos off protons and neutrons, thereby being very challenging for direct detection experiments. However, a potential detection of smuons and selectrons at the LHC, together with a hypothetical discovery of a gamma-ray signal from neutralino annihilations in dwarf spheroidal galaxies could shed light on this kind of solutions. Finally, we have investigated the naturalness of these scenarios, taking into account all the potential sources of tuning. Besides the electroweak fine-tuning, we have found that the tuning to reproduce the correct DM relic abundance and that to match the measured Higgs mass can also be important when estimating the total degree of naturalness.

An Analysis of Intrinsicality

Abstract: The leading account of intrinsicality over the last thirty years has arguably been David Lewis's account in terms of perfect naturalness. Lewis's account, however, has three serious problems: i) it cannot allow necessarily coextensive properties to differ in whether they are intrinsic; ii) it falsely classifies non-qualitative properties like being Obama as non-intrinsic; and iii) it is incompatible with a number of metaphysical theories that posit irreducibly non-categorical properties. I argue that, as a result of these problems, Lewis's account should be rejected and replaced with an alternative account, which also analyses intrinsicality in terms of perfect naturalness, but which avoids these problems.

Lorentz violation naturalness revisited

Abstract: We revisit here the naturalness problem of Lorentz invariance violations on a simple toy model of a scalar field coupled to a fermion field via a Yukawa interaction. We first review some well-known results concerning the low-energy percolation of Lorentz violation from high energies, presenting some details of the analysis not explicitly discussed in the literature and discussing some previously unnoticed subtleties. We then show how a separation between the scale of validity of the effective field theory and that one of Lorentz invariance violations can hinder this low-energy percolation. While such protection mechanism was previously considered in the literature, we provide here a simple illustration of how it works and of its general features. Finally, we consider a case in which dissipation is present, showing that the dissipative behaviour does not percolate generically to lower mass dimension operators albeit dispersion does. Moreover, we show that a scale separation can protect from unsuppressed low-energy percolation also in this case.

Surprises with nonrelativistic naturalness

Abstract: We explore the landscape of technical naturalness for nonrelativistic systems, finding surprises which challenge and enrich our relativistic intuition already in the simplest case of a single scalar field. While the immediate applications are expected in condensed matter and perhaps in cosmology, the study is motivated by the leading puzzles of fundamental physics involving gravity: the cosmological constant problem and the Higgs mass hierarchy problem.

Data selection for naturalness in HMM-based speech synthesis

Abstract: I Can we identify which utterances in a corpus are the best to use for voice training, based on acoustic/prosodic features, and which utterances should be excluded because they will introduce noise, artifacts, or inconsistency into the voice? I Can we use found data such as radio broadcast news to build HMM-based synthesized voices? I Can we select a subset of training utterances from a corpus of found data to produce a better voice than one trained on all of the data? I Which voice training and modeling approaches work best for this type of data?

Face-to-face versus one-way and two-way videoconferencing: How medium naturalness and personality traits influence achievement and perceived learning?

Abstract: During the last years, an increasing portion of face-to-face teaching-learning processes in the academia is being replaced with online synchronous sessions. According to the Media Naturalness Theory [1], the effectiveness of e-learning is affected by differences in naturalness level of the communication media. The present study compared between learning in a face-to-face environment and learning in two online conditions (one-way and two-way video conferencing). We examined the influence of medium naturalness and personality traits (extroversion-introversion and emotional stability-neuroticism) on students' achievements and perceived learning. A controlled experiment was conducted with 76 participants attending a lesson that was composed of several teaching-learning components: frontal lecture, instructor-students interactions, students-instructor interactions, and peer interactions. Zoom videoconferencing application, which allows spontaneous participation, was utilized for e-learning. Results indicate that for the face-to-face learning condition, achievement was higher compared to one-way videoconferencing only for fact-related questions, but not for inference questions or overall test score. We also found that low level of medium naturalness was associated with lower scores only for neurotic students. No clear evidence that links extroversion-introversion trait to academic performance was found. All aspects of perceived learning showed consistent advantage for emotionally stable participants and extroverts, compared to neurotic students and introverts.1

Data Selection and Adaptation for Naturalness in HMM-Based Speech Synthesis.

Abstract: We describe experiments in building HMM text-to-speech voices on professional broadcast news data from multiple speakers. We build on earlier work comparing techniques for selecting utterances from the corpus and voice adaptation to produce the most natural-sounding voices. While our ultimate goal is to develop intelligible and natural-sounding synthetic voices in low-resource languages rapidly and without the expense of collecting and annotating data specifically for text-to-speech, we focus on English initially, in order to develop and evaluate our methods. We evaluate our approaches using crowdsourced listening tests for naturalness. We have found that removing utterances that are outliers with respect to hyper-articulation, as well as combining the selection of hypoarticulated utterances and low mean f0 utterances, produce the most natural-sounding voices.

Lorentz violation naturalness revisited

Abstract: We revisit here the naturalness problem of Lorentz invariance violations on a simple toy model of a scalar field coupled to a fermion field via a Yukawa interaction. We first review some well-known results concerning the low-energy percolation of Lorentz violation from high energies, presenting some details of the analysis not explicitly discussed in the literature and discussing some previously unnoticed subtleties. We then show how a separation between the scale of validity of the effective field theory and that one of Lorentz invariance violations can hinder this low-energy percolation. While such protection mechanism was previously considered in the literature, we provide here a simple illustration of how it works and of its general features. Finally, we consider a case in which dissipation is present, showing that the dissipative behaviour does not percolate generically to lower mass dimension operators albeit dispersion does. Moreover, we show that a scale separation can protect from unsuppressed low-energy percolation also in this case.

Neutral naturalness with bifundamental gluinos

Abstract: We study constraints on one-loop neutral naturalness at the LHC by considering gluon partners which are required to ameliorate the tuning in the Higgs mass-squared arising at two loops. This is done with a simple orbifold model of folded supersymmetry which not only contains color-neutral stops but also bifundamental gluinos that are charged under the Standard Model color group $SU(3)_C$ and a separate $SU(3)_C'$ group. The bifundamental gluinos reduce the Higgs mass tuning at two loops and maintain naturalness provided the gluinos are lighter than approximately 1.9 TeV for a 5 TeV cutoff scale. Limits from the LHC already forbid bifundamental gluinos below 1.4 TeV, and other non-colored states such as electroweakinos, $Z'$ bosons and dark sector bound states may be probed at future colliders. The search for bifundamental gluinos therefore provides a direct probe of one-loop neutral naturalness that can be fully explored at the LHC.