Hierarchical Spectrum Research Articles

Natural fermion hierarchies from random Yukawa couplings

The Standard Model of particle physics requires Yukawa matrices with eigenvalues that differ by orders of magnitude. We propose a novel way to explain this fact without any small or large parameters. The mechanism is based on the observation that products of matrices of random order-one numbers have hierarchical spectra. The same mechanism can easily account for the hierarchical structure of the quark mixing matrix.

Caste Hierarchies and Social Tensions in Cuttack: 1920–30

The emergence of caste as a key category of classification, enumeration and control under colonial rule has created a refectory taxonomy of administrative categories through officially enforced labelling activities. The census categories made an opportunity to occupy institutional space and promoted identification with caste and stimulated lower caste people, such as the Bauri community, for their rights and representations. The stigma associated with the native agencies, such as Chamars, Pig Herds (Ghusuria) and others in the Hindu stratification, was challenged by the anti-colonial nationalist, who re-signified them as sites of cultural authenticity and collective sovereignty. The government’s passion for labels and pigeonhole, which led to crystallisation of caste system, could hardly tame intractability or ‘vagueness’ of social category in the middle rung and spurred a series of negotiations and contestations among the caste groups across the Hindu hierarchical spectrum. As against, it transfigured in the colonial modernity’s endeavour to grapple with tensions between the universal and particular, normative and stigmatised subjects leading to caste radicalism’s re-exegesis of Hindu religious tradition to produce an original ( Adidharma) view of social stratification and the post-colonial state reinforcing it by a rational legal regime opposed to the idea of civic inequality.

New and trivialCPsymmetry for extendedA4flavor

The combination of $\nu_\mu$-$\nu_\tau$ exchange together with CP conjugation in the neutrino sector (known as $\mathrm{CP}^{\mu\tau}$ symmetry or $\mu\tau$-reflection) is known to predict the viable pattern: $\theta_{23}=45^\circ$, maximal Dirac CP phase and trivial Majorana phases. We implement such a CP symmetry as a new CP symmetry in theories with $A_4$ flavor. The implementation in a complete renormalizable model leads to a new form for the neutrino mass matrix that leads to further predictions: normal hierarchical spectrum with lightest mass and $m_{\beta\beta}$ ($0\nu\beta\beta$) of only few meV, and either $\nu_1$ or $\nu_2$ has opposite CP parity. An approximate $L_\mu-L_\tau$ symmetry arises naturally and controls the flavor structure of the model. The light neutrino masses are generated by the extended seesaw mechanism with 6 right-handed neutrinos (RHNs). The requirement of negligible one-loop corrections to light neutrino masses, validity of the extended seesaw approximation and not too long-lived BSM states to comply with BBN essentially restricts the parameters of the model to a small region: three relatively light right-handed neutrinos at the GeV scale, heavier neutrinos at the electroweak scale and Yukawa couplings smaller than the electron Yukawa. Such a small Yukawa couplings render these RHNs unobservable in terrestrial experiments.

Hierarchical Pairwise Error Probability for Hierarchical Decode and Forward Strategy in PLNC

Pairwise error probability (PEP) is an essential tool allowing to design practical optimized coding schemes. It reveals the connection between the performance and the decoding metric that is directly related to the codeword and/or constellation properties. The application of this principle to the hierarchical PEP used to describe the decoding performance of many-to-one message functions (hierarchical network code maps) in physical layer network coding (PLNC) is addressed in this letter. Unlike for the single-user case, the hierarchical PEP reveals a complicated dependence on the structure of the hierarchical codeword/constellation. The structure is defined in terms of hierarchical distance and hierarchical self-distance spectra . We show that the network coded modulation (NCM) minimizing the hierarchical decoding error probability should have zero self-distance spectrum leading to self-folded NCM design criterion .

Outage Analysis of a Multiple-Antenna Cognitive Radio System With Cooperative Decode-and-Forward Relaying

In this paper, we analyze a two-phase hierarchical spectrum sharing protocol based on cooperative decode and forward relay transmission wherein it is assumed that the cognitive (i.e secondary) system is equipped with multiple antennas. The performance of the licensed (i.e. primary) as well as cognitive system is quantified by deriving the closed form expressions for outage probability. The theoretical and simulation results show that by exploiting multiple antennas at secondary transmitter (ST), we can drastically improve the performance of both primary and secondary systems as compared to conventional spectrum sharing schemes.

The double mass hierarchy pattern: Simultaneously understanding quark and lepton mixing

The charged fermion masses of the three generations exhibit the two strong hierarchies m3≫m2≫m1. We assume that also neutrino masses satisfy mν3>mν2>mν1 and derive the consequences of the hierarchical spectra on the fermionic mixing patterns. The quark and lepton mixing matrices are built in a general framework with their matrix elements expressed in terms of the four fermion mass ratios, mu/mc, mc/mt, md/ms and ms/mb, and me/mμ, mμ/mτ, mν1/mν2 and mν2/mν3, for the quark and lepton sector, respectively. In this framework, we show that the resulting mixing matrices are consistent with data for both quarks and leptons, despite the large leptonic mixing angles. The minimal assumption we take is the one of hierarchical masses and minimal flavor symmetry breaking that strongly follows from phenomenology. No special structure of the mass matrices has to be assumed that cannot be motivated by this minimal assumption. This analysis allows us to predict the neutrino mass spectrum and set the mass of the lightest neutrino well below 0.01 eV. The method also gives the 1σ allowed ranges for the leptonic mixing matrix elements. Contrary to the common expectation, leptonic mixing angles are found to be determined solely by the four leptonic mass ratios without any relation to symmetry considerations as commonly used in flavor model building. Still, our formulae can be used to build up a flavor model that predicts the observed hierarchies in the masses — the mixing follows then from the procedure which is developed in this work.

Limits on new physics from black holes

Black holes emit high energy particles which induce a finite density potential for any scalar field $\phi$ coupling to the emitted quanta. Due to energetic considerations, $\phi$ evolves locally to minimize the effective masses of the outgoing states. In theories where $\phi$ resides at a metastable minimum, this effect can drive $\phi$ over its potential barrier and classically catalyze the decay of the vacuum. Because this is not a tunneling process, the decay rate is not exponentially suppressed and a single black hole in our past light cone may be sufficient to activate the decay. Moreover, decaying black holes radiate at ever higher temperatures, so they eventually probe the full spectrum of particles coupling to $\phi$. We present a detailed analysis of vacuum decay catalyzed by a single particle, as well as by a black hole. The former is possible provided large couplings or a weak potential barrier. In contrast, the latter occurs much more easily and places new stringent limits on theories with hierarchical spectra. Finally, we comment on how these constraints apply to the standard model and its extensions, e.g. metastable supersymmetry breaking.

Water Extraction in High Resolution Remote Sensing Image Based on Hierarchical Spectrum and Shape Features

This paper addresses the problem of water extraction from high resolution remote sensing images (including R, G, B, and NIR channels), which draws considerable attention in recent years. Previous work on water extraction mainly faced two difficulties. 1) It is difficult to obtain accurate position of water boundary because of using low resolution images. 2) Like all other image based object classification problems, the phenomena of "different objects same image" or "different images same object" affects the water extraction. Shadow of elevated objects (e.g. buildings, bridges, towers and trees) scattered in the remote sensing image is a typical noise objects for water extraction. In many cases, it is difficult to discriminate between water and shadow in a remote sensing image, especially in the urban region. We propose a water extraction method with two hierarchies: the statistical feature of spectral characteristic based on image segmentation and the shape feature based on shadow removing. In the first hierarchy, the Statistical Region Merging (SRM) algorithm is adopted for image segmentation. The SRM includes two key steps: one is sorting adjacent regions according to a pre-ascertained sort function, and the other one is merging adjacent regions based on a pre-ascertained merging predicate. The sort step is done one time during the whole processing without considering changes caused by merging which may cause imprecise results. Therefore, we modify the SRM with dynamic sort processing, which conducts sorting step repetitively when there is large adjacent region changes after doing merging. To achieve robust segmentation, we apply the merging region with six features (four remote sensing image bands, Normalized Difference Water Index (NDWI), and Normalized Saturation-value Difference Index (NSVDI)). All these features contribute to segment image into region of object. NDWI and NSVDI are discriminate between water and some shadows. In the second hierarchy, we adopt the shape features to remove more shadows. The water polygons are generated by vectorization algorithm after water segmentation, and then some shape parameters (Compact, Critical Point and Symmetry) are considered to remove shadow. To evaluate the performance of the proposed method, we collect several Quick Bird images at 0.61-m resolution which are acquired in May 2009 at GUANGZHOU province of China. The proposed method is compared with four other methods in water extraction, including pixel-based segmentation by NDWI, Mean-sift segmentation by NDWI, and SVM with different channels. Experimental results show that the proposed method can increase extraction accuracy and reduce the influence of shadows.

Technique of Software Fault Localization Based on Hierarchical Slicing Spectrum

A commonly-used software fault localization technique mainly utilizes testing coverage information to calculate the suspiciousness of each program statement to find the faulty statement.However,this technique does not fully take dependences of the program into account;thus,its capacity for precisely locating faults is limited.This paper proposes a more effective hierarchical slicing spectrum-based software fault localization(HSS-SFL) technique for object-oriented programs.HSS-SFL first analyzes the dependence among the elements at different granularity levels including package level,class level,method level and statement level,and deletes some elements which are unrelated to the failed testing outputs.Next,the technique builds the hierarchical slicing spectrum model for these hierarchical slices obtained from the previous step,and further defines a suspiciousness method for each slice element.Finally,the faulty statement is located according to the suspiciousness results.Experimental results on real application programs show that HSS-SFL is more effective to locate the fault than program spectrum-based Tarantula technique,Union technique and Intersection technique.

Hierarchical spectrum market and the design of contracts for mobile providers

In this paper, we propose a hierarchical market structure and contracting mechanisms that could be used by wireless/mobile service providers to trade spectrum and spectrum-derived services with each other. This market advances beyond the current contracting mechanisms between service providers that, due to availability of only long-term contract choices, do not lead to efficient utilization of spectrum resources and service innovation for the customers. We describe the spectrum market structure in terms of the role of the providers and the different spectrum contract types that could be traded in the marketplace. Finally, the role and function of present day mobile virtual networks operators (MVNO) and the mobile network operators (MNO) are discussed from the context of the proposed market structure.

Can heavy neutrinos dominate neutrinoless double beta decay?

We study whether a dominant contribution to neutrinoless double beta decay coming from extra heavy degrees of freedom, introduced to generate the light neutrino masses, can dominate over the light neutrino contribution. It has been shown that this may occur at tree-level if the light neutrino contribution partially cancels out. Here we focus on this case, specifically in the context of type-I seesaw models paying special attention to the one-loop corrections to light neutrino masses, their contribution to the process and correlation with the heavy sector. We perform a general analysis without restricting the study to any particular region of the parameter space, although interesting limits associated with inverse and extended seesawlike models are discussed in more detail. It turns out that the heavy neutrinos can dominate the process only in those limits. For the inverse seesaw limit, we find a very constrained allowed region of the parameter space, with heavy neutrino masses around 5 GeV. The extended seesaw case allows for a larger region, but in general, a hierarchical spectrum of heavy neutrinos with masses above and below $\sim100$ MeV is required.

Ultrametricity of the state space in glasses

We review the results related to the ultrametricity notion in glasses. We present the proof of the ultrametricity of the replica space for an arbitrary spin glass model with reflection symmetry. We solve the problem of describing the dynamics of a system with an ultrametric state space using the Keldysh functional method for nonequilibrium dynamics in which the quasinonergodicity of the system is taken into account by introducing a hierarchical spectrum of relaxation times.

Dynamic Cooperative Secondary Access in Hierarchical Spectrum Sharing Networks

We address the challenge of energy efficiency in hierarchical spectrum sharing networks with dynamic traffic. We consider a primary and a cognitive secondary transmitter–receiver pair, where the secondary transmitter can utilize cooperative transmission to relay primary traffic while superimposing its own information. The secondary user meets a dilemma in this scenario. By choosing cooperation, it can transmit a packet immediately, but it has to bear the additional cost of relaying. Otherwise, it can wait for the primary user to become idle, which increases the queuing delay that secondary packets experience. To solve this dilemma and trade off delay and energy consumption, we propose dynamic cooperative secondary access control that takes the state of the spectrum sharing network into account. We formulate the problem as a Markov decision process and prove the existence of a stationary policy that is average cost optimal. We evaluate reinforcement learning to find optimal transmission strategy when the traffic and link statistics are not known. We demonstrate that dynamic cooperation is necessary for the secondary system to be able to adapt to changing network conditions and show that optimal sequential decision can significantly improve the tradeoff of the energy consumption and the delay.

Statistical Routing for Multihop Wireless Cognitive Networks

To account for the randomness of propagation channels and interference levels in hierarchical spectrum sharing, a novel approach to multihop routing is introduced for cognitive random access networks, whereby packets are randomly routed according to outage probabilities. Leveraging channel and interference level statistics, the resultant cross-layer optimization framework provides optimal routes, transmission probabilities, and transmit-powers, thus enabling cognizant adaptation of routing, medium access, and physical layer parameters to the propagation environment. The associated optimization problem is non-convex, and hence hard to solve in general. Nevertheless, a successive convex approximation approach is adopted to efficiently find a Karush-Kuhn-Tucker solution. Augmented Lagrangian and primal decomposition methods are employed to develop a distributed algorithm, which also lends itself to online implementation. Enticingly, the fresh look advocated here permeates benefits also to conventional multihop wireless networks in the presence of channel uncertainty.

Hierarchically acting sterile neutrinos

AbstractWe propose that a hierarchical spectrum of sterile neutrinos (eV, keV, 1013–15 GeV) is considered as the explanation for MiniBooNE and LSND oscillation anomalies, dark matter, and baryon asymmetry of the universe (BAU), respectively. The scenario can also realize the smallness of active neutrino masses by the seesaw mechanism.

Erratum: Renormalization group evolution in the type I and type II seesaw model [Phys. Rev. D76, 073010 (2007)

We carefully analyze the renormalization group equations in the type I + II seesaw scenario in the extended standard model (SM) and minimal supersymmetric standard model (MSSM). Furthermore, we present analytic formulae of the mixing angles and phases and discuss the RG effect on the different mixing parameters in the type II seesaw scenario. The renormalization group equations of the angles have a contribution which is proportional to the mass squared difference for a hierarchical spectrum. This is in contrast to the inverse proportionality to the mass squared difference in the effective field theory case.

Cross-Layer QoS Provisioning in Cognitive Radio Networks

This letter investigates the quality of service provisioning in infrastructure-based secondary cognitive radio networks operating in compliance with the hierarchical spectrum overlay approach for dynamic spectrum access. A cross-layer analytical model is developed and a novel cross-layer approach for quality of service provisioning of the secondary users is proposed and validated by extensive simulation experiments.

Naturally split supersymmetry

Abstract Nonobservation of superparticles till date, new Higgs mass limits from the CMS and ATLAS experiments, WMAP constraints on relic density, various other low energy data, and the naturalness consideration, all considered simultaneously imply a paradigm shift of supersymmetric model building. In this paper we perform, for the first time, a detailed numerical study of brane-world induced supersymmetry breaking for both minimal and next-to-minimal scenarios. We observe that a naturally hierarchical spectrum emerges through an interplay of bulk, brane-localized and quasi-localized fields, which can gain more relevance in the subsequent phases of the LHC run.

Spread Supersymmetry

In the multiverse the scale of supersymmetry breaking, $$ \widetilde{m} = {F_X}/{M_{ * }} $$ ∗, may scan and environmental constraints on the dark matter density may exclude a large range of m from the reheating temperature after inflation down to values that yield a lightest supersymmetric particle (LSP) mass of order a TeV. After selection effects, for example from the cosmological constant, the distribution for $$ \widetilde{m} $$ in the region that gives a TeV LSP may prefer larger values. A single environmental constraint from dark matter can then lead to multi-component dark matter, including both axions and the LSP, giving a TeV-scale LSP somewhat lighter than the corresponding value for single-component LSP dark matter. If supersymmetry breaking is mediated to the Standard Model sector at order X † X and higher, only squarks, sleptons and one Higgs doublet acquire masses of order $$ \widetilde{m} $$ . The gravitino mass is lighter by a factor of M ∗ /M Pl and the gaugino masses are suppressed by a further loop factor. This Spread Supersymmetry spectrum has two versions, one with Higgsino masses arising from supergravity effects of order the gravitino mass giving a wino LSP, and another with the Higgsino masses generated radiatively from gaugino masses giving a Higgsino LSP. The environmental restriction on dark matter fixes the LSP mass to the TeV domain, so that the squark and slepton masses are order 103 TeV and 106 TeV in these two schemes. We study the spectrum, dark matter and collider signals of these two versions of Spread Supersymmetry. The Higgs boson is Standard Model-like and predicted to lie in the range 110-145 GeV; monochromatic photons in cosmic rays arise from dark matter annihilations in the halo; exotic short charged tracks occur at the LHC, at least for the wino LSP; and there are the eventual possibilities of direct detection of dark matter and detailed exploration of the TeV-scale states at a future linear collider. Gauge coupling unification is at least as precise as in minimal supersymmetric theories. If supersymmetry breaking is also mediated at order X, a much less hierarchical spectrum results. The spectrum in this case is similar to that of the Minimal Supersymmetric Standard Model, but with the superpartner masses 1-2 orders of magnitude larger than those expected in natural theories.

On the Gain of Primary Exclusion Region and Vertical Cooperation in Spectrum Sharing Wireless Networks

The emerging cognitive radio (CR) technology enables the introduction of hierarchical spectrum sharing in wireless networks, where the primary users (PUs) have transmission guarantees, but the coexisting secondary users (SUs) need to be cognitive toward primary activities and adjust their transmissions to conform to the primary constraints. We consider large-scale coexisting primary and secondary networks, where concurrent primary and secondary transmissions are allowed and where the SUs control the interference at the primary receivers by tuning the probability of transmitting and by forming a primary exclusive region (PER) around each primary receiver within which all SUs have to be silent. Moreover, the primary source-destination pairs utilize vertical cooperation by selecting a nearby SU to act as a cooperative relay. We define a unified analytic framework to model cognition and cooperative transmission in large-scale networks. We characterize the achievable gains considering the transmission density region and show that both of the networks have strong incentives to participate in the collaboration.