Centro Brasileiro de Pesquisas Fisicas
We present high signal-to-noise galaxy-galaxy lensing measurements of the BOSS CMASS sample using 250 square degrees of weak lensing data from CFHTLenS and CS82. We compare this signal with predictions from mock catalogs trained to match observables including the stellar mass function and the projected and two dimensional clustering of CMASS. We show that the clustering of CMASS, together with standard models of the galaxy-halo connection, robustly predicts a lensing signal that is 20-40% larger than observed. Detailed tests show that our results are robust to a variety of systematic effects. Lowering the value of S8=σ8Ωm/0.3S_{\rm 8}=\sigma_{\rm 8} \sqrt{\Omega_{\rm m}/0.3} compared to Planck2015 reconciles the lensing with clustering. However, given the scale of our measurement (r<10 h1h^{-1} Mpc), other effects may also be at play and need to be taken into consideration. We explore the impact of baryon physics, assembly bias, massive neutrinos, and modifications to general relativity on ΔΣ\Delta\Sigma and show that several of these effects may be non-negligible given the precision of our measurement. Disentangling cosmological effects from the details of the galaxy-halo connection, the effects of baryons, and massive neutrinos, is the next challenge facing joint lensing and clustering analyses. This is especially true in the context of large galaxy samples from Baryon Acoustic Oscillation surveys with precise measurements but complex selection functions.
We present high signal-to-noise galaxy-galaxy lensing measurements of the BOSS CMASS sample using 250 square degrees of weak lensing data from CFHTLenS and CS82. We compare this signal with predictions from mock catalogs trained to match observables including the stellar mass function and the projected and two dimensional clustering of CMASS. We show that the clustering of CMASS, together with standard models of the galaxy-halo connection, robustly predicts a lensing signal that is 20-40% larger than observed. Detailed tests show that our results are robust to a variety of systematic effects. Lowering the value of S8=σ8Ωm/0.3S_{\rm 8}=\sigma_{\rm 8} \sqrt{\Omega_{\rm m}/0.3} compared to Planck2015 reconciles the lensing with clustering. However, given the scale of our measurement (r<10 h1h^{-1} Mpc), other effects may also be at play and need to be taken into consideration. We explore the impact of baryon physics, assembly bias, massive neutrinos, and modifications to general relativity on ΔΣ\Delta\Sigma and show that several of these effects may be non-negligible given the precision of our measurement. Disentangling cosmological effects from the details of the galaxy-halo connection, the effects of baryons, and massive neutrinos, is the next challenge facing joint lensing and clustering analyses. This is especially true in the context of large galaxy samples from Baryon Acoustic Oscillation surveys with precise measurements but complex selection functions.
We introduce the α\alpha-Gauss-Logistic map, a new nonlinear dynamics constructed by composing the logistic and α\alpha-Gauss maps. Explicitly, our model is given by $x_{t+1} = f_L(x_t)x_t^{-\alpha} - \lfloor f_L(x_t)x_t^{-\alpha} \rfloor where where f_L(x_t) = r x_t (1-x_t)$ is the logistic map and \lfloor \ldots \rfloor is the integer part function. Our investigation reveals a rich phenomenology depending solely on two parameters, rr and α\alpha. For \alpha &lt; 1, the system exhibits a gradual period-doubling route to chaos as the parameter rr is increased, interspersed with stability windows within the chaotic attractor. In contrast, for $1 \leq \alpha < 2$, the onset of chaos is abrupt, occurring without any prior bifurcations, and the resulting chaotic attractors emerge without stability windows. For α2\alpha \geq 2, the regular behavior is absent. The special case of α=1\alpha = 1 allows an analytical treatment, yielding a closed-form formula for the Lyapunov exponent and conditions for an exact uniform invariant density, using the Perron-Frobenius equation. Chaotic regimes for α=1\alpha = 1 can exhibit gaps or be gapless. Surprisingly, the golden ratio Φ\Phi marks the threshold for the disappearance of the largest gap in the regime diagram. Additionally, at the edge of chaos in the abrupt transition regime, the invariant density approaches a qq-Gaussian with q=2q=2, which corresponds to a Cauchy distribution.
We present in this work an exact renormalization group (RG) treatment of a one-dimensional pp-wave superconductor. The model proposed by Kitaev consists of a chain of spinless fermions with a pp-wave gap. It is a paradigmatic model of great actual interest since it presents a weak pairing superconducting phase that has Majorana fermions at the ends of the chain. Those are predicted to be useful for quantum computation. The RG allows to obtain the phase diagram of the model and to study the quantum phase transition from the weak to the strong pairing phase. It yields the attractors of these phases and the critical exponents of the weak to strong pairing transition. We show that the weak pairing phase of the model is governed by a chaotic attractor being non-trivial from both its topological and RG properties. In the strong pairing phase the RG flow is towards a conventional strong coupling fixed point. Finally, we propose an alternative way for obtaining pp-wave superconductivity in a one-dimensional system without spin-orbit interaction.
Context: The induced gravitational collapse (IGC) paradigm addresses the very energetic (10^{52}-10^{54}erg) long gamma-ray bursts (GRBs) associated to supernovae (SNe). Unlike the traditional "collapsar" model, an evolved FeCO core with a companion neutron star (NS) in a tight binary system is considered as the progenitor. This special class of sources, here named "binary driven hypernovae" (BdHNe), presents a composite sequence composed of four different episodes [...]. Aims: We first compare and contrast the steep decay, the plateau and the power-law decay of the X-ray luminosities of three selected BdHNe [...]. Second, to explain the different sizes and Lorentz factors of the emitting regions of the four Episodes, [...]. Finally, we show the possible role of r-process, which originates in the binary system of the progenitor.. Methods: We compare and contrast the late X-ray luminosity of the above three BdHNe. We examine correlations between the time at the starting point of the constant late power-law decay, t^*_a, the average prompt luminosity, , and the luminosity at the end of the plateau, L_a. We analyze a thermal emission (~0.97-0.29 keV), observed during the X-ray steep decay phase of GRB 090618. Results: The late X-ray luminosities of the three BdHNe [...] show a precisely constrained "nested" structure [...]. Conclusions: We confirm a constant slope power-law behavior for the late X-ray luminosity in the source rest-frame, which may lead to a new distance indicator for BdHNe. These results, as well as the emitter size and Lorentz factor, appear to be inconsistent with the traditional afterglow model based on synchrotron emission from an ultra-relativistic [...] collimated jet outflow. We argue, instead, for the possible role of r-process, originating in the binary system, to power the mildly relativistic X-ray source.
CNRS logoCNRSMichigan State University logoMichigan State UniversityCharles UniversityNew York University logoNew York UniversityUniversity of Chicago logoUniversity of ChicagoNikhefINFN logoINFNPennsylvania State UniversityCONICETUniversidade de LisboaLouisiana State UniversityUniversidad de GranadaColorado State UniversityUniversity of Tokyo logoUniversity of TokyoPolitecnico di MilanoCase Western Reserve UniversityFermi National Accelerator LaboratoryBergische Universität WuppertalUniversidade Federal FluminenseObservatorio Pierre AugerUniversidade Federal do ABCUniversity of DelawareUniversidad Nacional de La PlataUniversidade Federal do Rio de JaneiroMichigan Technological UniversityUniversität SiegenInstitute of Physics of the Czech Academy of SciencesGran Sasso Science Institute (GSSI)Max-Planck-Institut für RadioastronomieUniversity of AdelaideInstituto BalseiroKarlsruhe Institute of Technology (KIT)Benemérita Universidad Autónoma de PueblaUniversità dell’AquilaASTRONNational Centre for Nuclear ResearchRadboud University NijmegenUniversidade de Santiago de CompostelaGrenoble-INPUniversidad Michoacana de San Nicolás de HidalgoUNCUYOCNEAIJCLabCentrum Wiskunde & Informatica (CWI)Universidade Federal Rural do Rio de JaneiroUniversidad Industrial de SantanderJ. Stefan InstitutePontif ́ıcia Universidade Cat ́olica do Rio de JaneiroPalacky UniversityUniversità di MilanoOberlin CollegeUniversidade Federal de Sao CarlosInstitute for Cosmic Ray ResearchUniversidad Nacional de San LuisCentro Brasileiro de Pesquisas FisicasUniversità Federico II di NapoliCAFPEUniversity of Nova GoricaIFLPInstitute for Space SciencesUniversidade Estadual de Feira de SantanaUNSAMUniversity of Ł ́od ́zUNRLaboratoire de Physique Subatomique et de Cosmologie (LPSC)Universidade São PauloUniversidade Federal de Itajub ́a – UNIFEIHoria Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH)Comisión Nacional de Energ ́ıa AtómicaInteruniversity Institute for High-Energy Physics (IIHE)Laboratoire de Physique Nucle ́naire et de Hautes Energies (LPNHE)Laboratório de Instrumentac ̧ão e F ́ısica Experimental de Part ́ıculas – LIPUniversidade Federal Tecnológica do ParanáUniversidad Tecnol ́ogica Nacional – Facultad Regional Buenos AiresInstituto de Tecnolog ́ıas en Detección y Astropart ́ıculas (ITeDA)ITP – Universidade Federal de São CarlosComisión Nacional de Actividades Espaciales (CONAE)Instituto Argentino de Radioastronom ́ıa (IAR)Universit di CataniaUniversidad Nacional Autónoma de M´exicoSorbonne Universit eUniversit ´e Grenoble AlpesUniversit del SalentoUniversit Libre de BruxellesInstituto Superior T ecnico ISTRWTH Aachen UniversityUniversit e Paris-SaclayUniversit di TorinoCentro At ómico BarilocheUniversit e Paris DiderotUniversit di Roma Tor VergataUniversity of Wisconsin ","MilwaukeeVrije Universiteit Brussel
We report a measurement of the energy spectrum of cosmic rays above 2.5×10182.5{\times} 10^{18} eV based on 215,030215,030 events. New results are presented: at about 1.3×10191.3{\times} 10^{19} eV, the spectral index changes from 2.51±0.03 (stat.)±0.05 (sys.)2.51 \pm 0.03 \textrm{ (stat.)} \pm 0.05 \textrm{ (sys.)} to 3.05±0.05 (stat.)±0.10 (sys.)3.05 \pm 0.05 \textrm{ (stat.)}\pm 0.10\textrm{ (sys.)}, evolving to 5.1±0.3 (stat.)±0.1 (sys.)5.1\pm0.3\textrm{ (stat.)} \pm 0.1\textrm{ (sys.)} beyond 5×10195{\times} 10^{19} eV, while no significant dependence of spectral features on the declination is seen in the accessible range. These features of the spectrum can be reproduced in models with energy-dependent mass composition. The energy density in cosmic rays above 5×10185{\times} 10^{18} eV is (5.66±0.03 (stat.)±1.40 (sys.))×1053 (5.66 \pm 0.03 \textrm{ (stat.)} \pm 1.40 \textrm{ (sys.)} ) {\times} 10^{53}~erg Mpc3^{-3}.
We present a quantum version of the vacuum Bianchi IX model by implementing affine coherent state quantization combined with a Born-Oppenheimer-like adiabatic approximation. The analytical treatment is carried out on both quantum and semiclassical levels. The resolution of the classical singularity occurs by means of a repulsive potential generated by our quantization procedure. The quantization of the oscillatory degrees of freedom produces a radiation energy density term in the semiclassical constraint equation. The Friedmann-like lowest energy eigenstates of the system are found to be dynamically stable.
The Gauss map (or continued fraction map) is an important dissipative one-dimensional discrete-time dynamical system that exhibits chaotic behaviour and which generates a symbolic dynamics consisting of infinitely many different symbols. Here we introduce a generalization of the Gauss map which is given by xt+1=1xtα[1xtα]x_{t+1}=\frac{1}{x_t^\alpha} - \Bigl[\frac{1}{x_t^\alpha} \Bigr] where α0\alpha \geq 0 is a parameter and xt[0,1]x_t \in [0,1] (t=0,1,2,3,t=0,1,2,3,\ldots). The symbol [][\dots ] denotes the integer part. This map reduces to the ordinary Gauss map for α=1\alpha=1. The system exhibits a sudden `jump into chaos' at the critical parameter value α=αc0.241485141808811\alpha=\alpha_c \equiv 0.241485141808811\dots which we analyse in detail in this paper. Several analytical and numerical results are established for this new map as a function of the parameter α\alpha. In particular, we show that, at the critical point, the invariant density approaches a qq-Gaussian with q=2q=2 (i.e., the Cauchy distribution), which becomes infinitely narrow as ααc+\alpha \to \alpha_c^+. Moreover, in the chaotic region for large values of the parameter α\alpha we analytically derive approximate formulas for the invariant density, by solving the corresponding Perron-Frobenius equation. For α\alpha \to \infty the uniform density is approached. We provide arguments that some features of this transition scenario are universal and are relevant for other, more general systems as well.
It has previously been discovered that there is a universal power law behavior exhibited by the late X-ray emission (LXRE) of a "golden sample" (GS) of six long energetic GRBs, when observed in the rest-frame of the source. This remarkable feature, independent of the different isotropic energy (E_iso) of each GRB, has been used to estimate the cosmological redshift of some long GRBs. This analysis is extended here to a new class of 161 long GRBs, all with E_iso > 10^52 erg. These GRBs are indicated as binary-driven hypernovae (BdHNe) in view of their progenitors: a tight binary system composed of a carbon-oxygen core (CO_core) and a neutron star undergoing an induced gravitational collapse (IGC) to a black hole triggered by the CO_core explosion as a supernova (SN). We confirm the universal behavior of the LXRE for the "enlarged sample" (ES) of 161 BdHNe observed up to the end of 2015, assuming a double-cone emitting region. We obtain a distribution of half-opening angles peaking at 17.62 degrees, with a mean value of 30.05 degrees, and a standard deviation of 19.65 degrees. This, in turn, leads to the possible establishment of a new cosmological candle. Within the IGC model, such universal LXRE behavior is only indirectly related to the GRB and originates from the SN ejecta, of a standard constant mass, being shocked by the GRB emission. The fulfillment of the universal relation in the LXRE and its independence of the prompt emission, further confirmed in this article, establishes a crucial test for any viable GRB model.
We review the construction of the supersymmetric sigma model for unitary maps, using the color- flavor transformation. We then illustrate applications by three case studies in quantum chaos. In two of these cases, general Floquet maps and quantum graphs, we show that universal spectral fluctuations arise provided the pertinent classical dynamics are fully chaotic (ergodic and with decay rates sufficiently gapped away from zero). In the third case, the kicked rotor, we show how the existence of arbitrarily long-lived modes of excitation (diffusion) precludes universal fluctuations and entails quantum localization.
For the simulation of the scintillation and Cherenkov light propagation in large liquid scintillator detectors a detailed knowledge about the absorption and emission spectra of the scintillator molecules is mandatory. Furthermore reemission probabilities and quantum yields of the scintillator components influence the light propagation inside the liquid. Absorption and emission properties are presented for liquid scintillators using 2,5-Diphenyloxazole (PPO) and 4-bis-(2-Methylstyryl)benzene (bis-MSB) as primary and secondary wavelength shifter. New measurements of the quantum yields for various aromatic molecules are shown.
We investigate the constrained Minimal Supersymmetric Standard Model (cMSSM) in the light of constraining experimental and observational data from precision measurements, astrophysics, direct supersymmetry searches at the LHC and measurements of the properties of the Higgs boson, by means of a global fit using the program Fittino. As in previous studies, we find rather poor agreement of the best fit point with the global data. We also investigate the stability of the electro-weak vacuum in the preferred region of parameter space around the best fit point. We find that the vacuum is metastable, with a lifetime significantly longer than the age of the Universe. For the first time in a global fit of supersymmetry, we employ a consistent methodology to evaluate the goodness-of-fit of the cMSSM in a frequentist approach by deriving p-values from large sets of toy experiments. We analyse analytically and quantitatively the impact of the choice of the observable set on the p-value, and in particular its dilution when confronting the model with a large number of barely constraining measurements. Finally, for the preferred sets of observables, we obtain p-values for the cMSSM below 10%, i.e. we exclude the cMSSM as a model at the 90% confidence level.
In a paper by Umarov, Tsallis and Steinberg (2008), a generalization of the Fourier transform, called the qq-Fourier transform, was introduced and applied for the proof of a qq-generalized central limit theorem (qq-CLT). Subsequently, Hilhorst illustrated (2009 and 2010) that the qq-Fourier transform for q>1q>1 is not invertible in the space of density functions. Indeed, using an invariance principle, he constructed a family of densities with the same qq-Fourier transform and noted that "as a consequence, the qq-central limit theorem falls short of achieving its stated goal". The distributions constructed there have compact support. We prove now that the limit distribution in the qq-CLT is unique and can not have a compact support. This result excludes all the possible counterexamples which can be constructed using the invariance principle and fills the gap mentioned by Hilhorst.
Transverse spectra of both jets and hadrons obtained in high-energy pppp and ppˉp\bar p collisions at central rapidity exhibit power-law behavior of 1/pTn1/p_T^n at high pTp_T. The power index nn is 4-5 for jet production and is 6-10 for hadron production. Furthermore, the hadron spectra spanning over 14 orders of magnitude down to the lowest pTp_T region in pppp collisions at LHC can be adequately described by a single nonextensive statistical mechanical distribution that is widely used in other branches of science. This suggests indirectly the possible dominance of the hard-scattering process over essentially the whole pTp_T region at central rapidity in high-energy pppp and ppˉp \bar p collisions. We show here direct evidences of such a dominance of the hard-scattering process by investigating the power indices of UA1 and ATLAS jet spectra over an extended pTp_T region and the two-particle correlation data of the STAR and PHENIX Collaborations in high-energy pppp and ppˉp \bar p collisions at central rapidity. We then study how the showering of the hard-scattering product partons alters the power index of the hadron spectra and leads to a hadron distribution that may be cast into a single-particle nonextensive statistical mechanical distribution. Because of such a connection, the nonextensive statistical mechanical distribution may be considered as a lowest-order approximation of the hard-scattering of partons followed by the subsequent process of parton showering that turns the jets into hadrons, in high energy pppp and ppˉp\bar p collisions.
We explicitly calculate the Green functions describing quantum changes of topology in Friedman-Lemaitre-Robertson-Walker Universes whose spacelike sections are compact but endowed with distinct topologies. The calculations are performed using the long wavelength approximation at second order in the gradient expansion. We argue that complex metrics are necessary in order to obtain a non-vanishing Green functions and interpret this fact as demonstrating that a quantum topology change can be viewed as a quantum tunneling effect. We demonstrate that quantum topological transitions between curved hypersurfaces are allowed whereas no transition to or from a flat section is possible, establishing thus a selection rule. We also show that the quantum topology changes in the direction of negatively curved hypersurfaces are strongly enhanced as time goes on, while transitions in the opposite direction are suppressed.
In 1910 Einstein published a crucial aspect of his understanding of Boltzmann entropy. He essentially argued that the likelihood function of any system composed by two probabilistically independent subsystems {\it ought} to be factorizable into the likelihood functions of each of the subsystems. Consistently he was satisfied by the fact that Boltzmann (additive) entropy fulfills this epistemologically fundamental requirement. We show here that entropies (e.g., the qq-entropy on which nonextensive statistical mechanics is based) which generalize the BG one through violation of its well known additivity can {\it also} fulfill the same requirement. This fact sheds light on the very foundations of the connection between the micro- and macro-scopic worlds.
The Boltzmann-Gibbs-von Neumann entropy of a large part (of linear size L) of some (much larger) d-dimensional quantum systems follows the so-called area law (as for black holes), i.e., it is proportional to Ld1L^{d-1}. Here we show, for d=1,2, that the (nonadditive) entropy S_q satisfies, for a special value of $q \neq 1$, the classical thermodynamical prescription for the entropy to be extensive, i.e., SqLdS_q \propto L^d. Therefore, we reconcile with classical thermodynamics the area law widespread in quantum systems. Recently, a similar behavior was exhibited, by M. Gell-Mann, Y. Sato and one of us (C.T.), in mathematical models with scale-invariant correlations. Finally, we find that the system critical features are marked by a maximum of the special entropic index q.
We briefly review Boltzmann-Gibbs and nonextensive statistical mechanics as well as their connections with Fokker-Planck equations and with existing central limit theorems. We then provide some hints that might pave the road to the proof of a new central limit theorem, which would play a fundamental role in the foundations and ubiquity of nonextensive statistical mechanics. The basic novelty introduced within this conjectural theorem is the {\it generalization of the hypothesis of independence} of the NN random variables being summed. In addition to this, we also advance some nonlinear dynamical (possibly exact) relations which generalize the concepts of Lyapunov exponents, entropy production per unit time, and their interconnection as first proved by Pesin for chaotic systems.
In this lecture we briefly review the definition, consequences and applications of an entropy, SqS_q, which generalizes the usual Boltzmann-Gibbs entropy SBGS_{BG} (S1=SBGS_1=S_{BG}), basis of the usual statistical mechanics, well known to be applicable whenever ergodicity is satisfied at the microscopic dynamical level. Such entropy SqS_q is based on the notion of qq-exponential and presents properties not shared by other available alternative generalizations of SBGS_{BG}. The thermodynamics proposed in this way is generically {\it nonextensive} in a sense that will be qualified. The present framework seems to describe quite well a vast class of natural and artificial systems which are not ergodic nor close to it. The a priori calculation of qq is necessary to complete the theory and we present some models where this has already been achieved.
As early as 1902, Gibbs pointed out that systems whose partition function diverges, e.g. gravitation, lie outside the validity of the Boltzmann-Gibbs (BG) theory. Consistently, since the pioneering Bekenstein-Hawking results, physically meaningful evidence (e.g., the holographic principle) has accumulated that the BG entropy SBGS_{BG} of a (3+1)(3+1) black hole is proportional to its area L2L^2 (LL being a characteristic linear length), and not to its volume L3L^3. Similarly it exists the \emph{area law}, so named because, for a wide class of strongly quantum-entangled dd-dimensional systems, SBGS_{BG} is proportional to lnL\ln L if d=1d=1, and to Ld1L^{d-1} if d>1d>1, instead of being proportional to LdL^d (d1d \ge 1). These results violate the extensivity of the thermodynamical entropy of a dd-dimensional system. This thermodynamical inconsistency disappears if we realize that the thermodynamical entropy of such nonstandard systems is \emph{not} to be identified with the BG {\it additive} entropy but with appropriately generalized {\it nonadditive} entropies. Indeed, the celebrated usefulness of the BG entropy is founded on hypothesis such as relatively weak probabilistic correlations (and their connections to ergodicity, which by no means can be assumed as a general rule of nature). Here we introduce a generalized entropy which, for the Schwarzschild black hole and the area law, can solve the thermodynamic puzzle.
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