Can chaotic quantum energy levels statistics be characterized using information geometry and inference methods?

In this paper, we review our novel information-geometrodynamical approach to chaos (IGAC) on curved statistical manifolds and we emphasize the usefulness of our information-geometrodynamical entropy (IGE) as an indicator of chaoticity in a simple application. Furthermore, knowing that integrable and chaotic quantum antiferromagnetic Ising chains are characterized by asymptotic logarithmic and linear growths of their operator space entanglement entropies, respectively, we apply our IGAC to present an alternative characterization of such systems. Remarkably, we show that in the former case the IGE exhibits asymptotic logarithmic growth while in the latter case the IGE exhibits asymptotic linear growth.At this stage of its development, IGAC remains an ambitious unifying information-geometric theoretical construct for the study of chaotic dynamics with several unsolved problems. However, based on our recent findings, we believe that it could provide an interesting, innovative and potentially powerful way to study and understand the very important and challenging problems of classical and quantum chaos.     

Can macaques perceive place of articulation from formant transition information?

An important problem in speech perception is to determine how humans extract the perceptually invariant place of articulation information in the speech wave across variable acoustic contexts. Although analyses have been developed that attempted to classify the voiced stops /b/ versus /d/ from stimulus onset information, most of the human perceptual research to date suggests that formant transition information is more important than onset information. The purpose of the present study was to determine if animal subjects, specifically Japanese macaque monkeys, are capable of categorizing /b/ versus /d/ in synthesized consonant-vowel (CV) syllables using only formant transition information. Three monkeys were trained to differentiate CV syllables with a "go-left" versus a "go-right" label. All monkeys first learned to differentiate a /za/ versus /da/ manner contrast and easily transferred to three new vowel contexts /[symbol: see text], epsilon, I/. Next, two of the three monkeys learned to differentiate a /ba/ versus /da/ stop place contrast, but were unable to transfer it to the different vowel contexts. These results suggest that animals may not use the same mechanisms as humans do for classifying place contrasts, and call for further investigation of animal perception of formant transition information versus stimulus onset information in place contrasts.     

Can the photon velocity be derived from the Klein-Gordon equation?

In their most recent article, Grado-Caffaro et al. have addressed the question of the ‘photon velocity’. They have expressed the photon velocity in terms of the wavefunctions of the Klein-Gordon equation (Grado-Caffaro and Grado-Caffaro [4]). In this note, we closely follow their work and explicitly obtain the photon velocity using the free solutions of the Klein-Gordon equation. It is shown that the plane wave solutions give rise to six possible values of the photon velocity. Two of these solutions are the most expected (v=±c). The remaining four solutions, the real pair ±0.786c and the imaginary pair ±1.272ic are difficult to comprehend.     

Can particle creation by a black hole be described in terms of more familiar laboratory processes?

Particle creation by a black hole is described in terms of temperature corrections to the Casimir effect. The results of Levin, Polevoy, and Ritov for spectral and total Poynting vector for a fluctuating electromagnetic field in a plane vacuum gap between two arbitrary media with different temperatures in flat spacetime are applied to clarify the situation that exists between the horizon of a nonrotating black hole and spatial infinity. This helps to reveal the mechanism of particle creation. The Hawking radiation is born inside the bell formed by a potential barrier of a black hole in all the region [2M, ]. Its blackbody spectrum is due to the interaction of field fluctuations with the surface of the bell. The particles between the walls are virtual ones. They can become real after passing through the [3M, ] tail, appearing to an observer at future infinityJ ⁺ as real ones. The arguments for and against the present standpoint are discussed.     

Can contributions to B_s→l~+l~-γ from the magnetic-penguin operator with real photons in the standard model be neglected?

Using the Bs meson wave function extracted from non-leptonic Bs decays, we reevaluate the rare decays Bs→l+l- γ,(l=e,μ) in the Standard Model, including two kinds of contributions from the magnetic-penguin operator with virtual and real photons. We find that contributions to the exclusive decays from the magnetic-penguin operator b→sγ with real photons, which were regarded as negligible in the previous literature, are large and the branching ratios Bs→l+l-γ are enhanced by a factor of almost 2. With the predicted branching ratios of the order of 10-8, it is expected that these radiative dileptonic decays will be detected in LHC-b and B factories in the near future.     

Can the eigenstates of a many-body Hamiltonian be represented exactly using a general two-body cluster expansion?

It is proved that a recent conjecture that the exact ground-state wave function of an arbitrary many-fermion system with one- and two-body interactions may be represented by an exponential cluster expansion employing finite two-body operators, starting from any reference function sufficiently close to the exact eigenfunction, is not valid. We show that the space of initial reference functions which lead to the exact ground state is of dimension equal to the number of two-body operators. If the dimension of the multiparticle space is greater than the number of two-body operators, then the space of good reference functions is of measure zero in it.     

Can the crystallization rate be independent from the crystallization enthalpy? The case of amorphous silicon

The crystallization enthalpy measured in a large series of amorphous silicon (a-Si) materials varies within a factor of 2 from sample to sample (Kail et al 2011 Phys. Status Solidi RRL 5 361). According to the classical theory of nucleation, this variation should produce large differences in the crystallization kinetics leading to crystallization temperatures and activation energies exceeding 550?°C and 1.7 eV, respectively, the 'standard' values measured for a-Si obtained by self-implantation. In contrast, the observed crystallization kinetics is very similar for all the samples studied and has no correlation with the crystallization enthalpy. This discrepancy has led us to propose that crystallization in a-Si begins in microscopic domains that are almost identical in all samples, independently of their crystallization enthalpy. Probably the existence of microscopic inhomogeneities also plays a crucial role in the crystallization kinetics of other amorphous materials and glasses.     

Can climate sensitivity be estimated from short-term relationships of top-of-atmosphere net radiation and surface temperature?

Increasing the knowledge in climate radiative feedbacks is critical for current climate studies. This work focuses on short-term relationships between global mean surface temperature and top-of-atmosphere (TOA) net radiation. The relationships may be used to characterize the climate feedback as suggested by some recent studies. As those recent studies, an energy balance model with ocean mixed layer and both radiative and non-radiative heat sources is used here. The significant improvement of current model is that climate system memories are considered.Based on model simulations, short-term relationship between global mean surface temperature and TOA net radiation (or the linear striation feature as suggested by previous studies) might represent climate feedbacks when the system had no memories. However, climate systems with the same short-term feedbacks but different memories would have a similar linear striation feature. This linear striation feature reflects only fast components of climate feedbacks and may not represent the total climate feedback even when the memory length of climate systems is minimal. The potential errors in the use of short-term relationships in estimations of climate sensitivity could be big. In short time scales, fast climate processes may overwhelm long-term climate feedbacks. Thus, the climate radiative feedback parameter obtained from short-term data may not provide a reliable estimate of climate sensitivity. This result also suggests that long-term observations of global surface temperature and TOA radiation are critical in the understanding of climate feedbacks and sensitivities.     

Can the SU(5) running be neglected in the minimal N = 1 Sugra model?

The radiative breaking of the electroweak symmetry is analysed in the minimal N = 1 supergravity model when the running of the parameters between the Planck and the grand unification scales is considered. The SU(5) running opens up the parameter space of the SU(2) × U(1) breaking solutions, and in particular all the values ߊ₀| > 3 are allowed. The SU(5) running will modify the structure of the low-energy mass spectra and will lead to the possibility of having realistic ones for very small values of the gravitino mass m_3/2. Indeed, if the SU(5) evolution is considered, no lower bound on m_3/2 is needed to obtain acceptable spectra.