Perturbative Approach For Non Renormalizable Theories

Renormalization procedure is generalized to be applicable for non renormalizable theories. It is shown that introduction of an extra expansion parameter allows to get rid of divergences and express physical quantities as series of finite number of interdependent expansion parameters. Suggested method is applied to quantum (Einstein's) gravity.Comment: 14 pages (LaTEX file

Implementation of a Gauss convoluted Pandel PDF for track reconstruction in Neutrino Telescopes

A probability distribution function is presented which provides a realistic description of the detection of scattered photons. The resulting probabilities can be described analytically by means of a superposition of several special functions. These exact expressions can be evaluated numerically only for small distances and limited time residuals, due to computer accuracy limitations. In this report we provide approximations for the exact expressions in different regions of the distance-time residual space, defined by the detector geometry and the space-time scale of an event. These approximations can be evaluated numerically with a relative error with respect to the exact expression at the boundaries of less than 0.001.Comment: 9 pages, 4 figures Revision 1 : extended content 12 pages, 4 figures Accepted for publication in Astroparticle Physic

Insulator-metal-insulator transition and selective spectral weight transfer in a disordered strongly correlated system

We investigate the metal insulator transitions at finite temperature for the Hubbard model with diagonal alloy disorder. We solve the dynamical mean field theory equations with the non crossing approximation and we use the coherent potential approximation to handle disorder. The excitation spectrum is given for various correlation strength $U$ and disorder. Two successive metal insulator transitions are observed at integer filling values as $U$ is increased. An important selective transfer of spectral weight arises upon doping. The strong influence of the temperature on the low energy dynamics is studied in details.Comment: submitted to Phys. Rev.

Band-Insulator-Metal-Mott-Insulator transition in the half--filled t−t′t-t^{\prime} ionic-Hubbard chain

We investigate the ground state phase diagram of the half-filled $t-t^{\prime}$ repulsive Hubbard model in the presence of a staggered ionic potential $\Delta$, using the continuum-limit bosonization approach. We find, that with increasing on-site-repulsion $U$, depending on the value of the next-nearest-hopping amplitude $t^{\prime}$, the model shows three different versions of the ground state phase diagram. For $t^{\prime} < t^{\prime}_{\ast}$, the ground state phase diagram consists of the following three insulating phases: Band-Insulator at $U<U_{c}$, Ferroelectric Insulator at $U_{c} U_{c}$. For $t^{\prime} > t^{\prime}_{c}$ there is only one transition from a spin gapped metallic phase at $U U_{c}$. Finally, for intermediate values of the next-nearest-hopping amplitude $t^{\prime}_{\ast} < t^{\prime} < t^{\prime}_{c}$ we find that with increasing on-site repulsion, at $U_{c1}$ the model undergoes a second-order commensurate-incommensurate type transition from a band insulator into a metallic state and at larger $U_{c2}$ there is a Kosterlitz-Thouless type transition from a metal into a ferroelectric insulator.Comment: 9 pages 3 figure

Neuronal networks in epileptic encephalopathies with CSWC [Abstract]

Aim: Continues spikes and waves during slow sleep (CSWS) is an agerelated epileptic encephalopathy characterized by occurrence of diffuse,continues spike and wave discharges during NREM sleep, seizures andpsychomotor impairment. The aim of our study was to investigate theneuronal networks underling background oscillations of CSWC using thesource analysis method Dynamic Imaging of Coherent Sources (DICS)and renormalized partial directed coherence (RPDC). Methods: In order to investigate underlying network and effective con-nectivity within the detected network, a DICS analyses and renormalizedpartial directed coherence (RPDC) methods were applied. The baselinesleep EEG recordings and follow up sleep EEG recordings from 12Patients with CSWS were used for the analyses. Results and Conclusions: The results revealed that independent of aeti-ology and severely of the disease CSWS EEG pattern is associated withthe complex network of coherent sources in medial prefrontal cortex,somatosensory association cortex/posterior cingulate cortex, medial pre-frontal cortex, middle temporal gyrus/parahippocampal gyrus/insularcortex, Thalamus and cerebellum. The described network underlyingCSWS was found on both group and individual levels and was no longerobserved in follow up EEGs of the patients with normalized sleep EEGs,suggesting the specificity of the network for the CSWS pattern. Furtheron, for the first time, using RPDC analyses we investigated the hierarchywithin the described network, which showed that Thalamus, togetherwith mesial temporal and parietal regions may be seen as a central hub ofthe underlying network. The involvement of this thalamocortical net-work, which was no longer observed in normalized EEGs, and a furtherpropagation towards the frontal region may interfere with restructuringof cognitive networks in the sensitive phase of development

Long-range spin chirality dimer order in the Heisenberg chain with modulated Dzyaloshinskii-Moriya interactions

The ground-state phase diagram of a spin S = 1 2 XXZ Heisenberg chain with spatially modulated Dzyaloshinskii-Moriya interaction H= n{J(Sx nSx n+1 +Sy nSy n+1 )+JzSz nSz n+1 +[D0 +(−1)nD1](Sx nSy n+1 −S y nSx n+1 )}is studied using the continuum-limit bosonization approach and extensive density-matrix renormalizationgroupcomputations.Itisshownthattheeffectivecontinuum-limitbosonizedtheoryofthemodelisgivenby the double-frequency sine-Gordon model (DSG) where the frequencies, i.e., the scaling dimensions of the two competing cosine perturbation terms, depend on the effective anisotropy parameter γ∗ =Jz/ J2 +D2 0 +D2 1. Exploring the ground-state properties of the DSG model we show that the zero-temperature phase diagram contains the following four phases: (i) the ferromagnetic phase at γ∗ −1; (ii) the gapless Luttinger-liquid (LL) phase at−1 γ∗ C2 > 1 the gapped composite (C2) phase characterized in addition to the coexisting spin dimerization and alternating chirality patterns, by the presence of LRO antiferromagnetic order. The transition from the LL to the C1 phase at γ∗ C1 belongs to the Berezinskii-Kosterlitz-Thouless universality class, while the transition at γ∗ = γ∗ C2 from C1 to C2 phase is of the Ising type.Fil: Avalishvili, N.. Ilia State University; Georgia. Andronikashvili Institute of Physics; GeorgiaFil: Japaridze, G. I.. Ilia State University; Georgia. Andronikashvili Institute of Physics; GeorgiaFil: Rossini, Gerardo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin

PB15. Neurophysiological biomarker for the clinical development of tuberous sclerosis [Abstract]

Aim To investigate the neuronal networks in children with tuberous sclerosis complex (TS) undergoing treatment with Everolimus. Methods Sleep and wake electroencephalography (EEG) before and one year after the start of the treatment with Everolimus were investigated in 13 patients with TS. To investigate functional and effective connectivity within the network generating the delta and theta activity in the background sleep and wake EEG, the methods of dynamic imaging of coherent sources (DICS) and renormalized partial directed coherence (RPDC) were applied. Results Sources before the treatment. Independent of location of the tubera and severity of epilepsy, delta activity in the background EEG pattern in patients with TS was associated with the sources in the medial prefrontal cortex, the supplementary motor area and the putamen during sleep. Theta waves during sleep were associated with sources in the prefrontal cortex, sensory cortex, hippocampus and the thalamus. The sources of delta frequency during wakefulness were identified at the posterior parietal cortex, the parahippocampal gyrus and the Broca area. Sources at theta frequency were found at the sensorymotor cortex, the prefrontal cortex, the primary visual cortex and the thalamus at awake state. Sources after the treatment. The sources one year after the start of the therapy, for both delta and delta frequencies were located in the same areas as before, however with a significantly weaker strength of coherence. The RPDC analysis at baseline showed strong bidirectional connections between described sources. The RPDC analyses after the one year of treatment showed significantly weaker unidirectional connections within the described network. At the follow up patients were grouped in two groups; group 1: five patients with >50% reduction of seizures and spike wave index, group 2: eight patients with <50% reduction of seizures and spike wave index. Interestingly, at follow up patients from the group 1 had decreased values in absolute power of the sources, coherence values and strength of connections. Whereas, patients from the group 2 had increased values in all above mentioned parameters. Conclusion The current study described the neuronal network in children with severe epilepsies due to TS. Regardless of the locations of the tubera the DICS analyses showed a complex network of cortical and subcortical sources with strong bidirectional connections. The described network was significantly weaker after one year under the treatment with Everolimus and appears to be characteristic for the children with TS and severe epilepsy

POSSIBILITIES OF PURIFICATION OF HEAVY METALS CONTAMINATION IN SOILS

Methods of neutralisation of different types of soils contaminated with heavy metals are studied. Certain strains of microorganisms have been selected, local microflora has been studied and identified at the genus level in laboratory conditions. Considering the conducted works, development of modified forms of humic acids, stimulation of local microorganisms and creation of geochemical barriers using local natural raw materials is recomended. Obtained results makes possible to develop comprehensive and rational model by means of inovative technologies for effective purification of soils contaminated with heavy metals.Methods of neutralisation of different types of soils contaminated with heavy metals are studied. Certain strains of microorganisms have been selected, local microflora has been studied and identified at the genus level in laboratory conditions. Considering the conducted works, development of modified forms of humic acids, stimulation of local microorganisms and creation of geochemical barriers using local natural raw materials is recomended. Obtained results makes possible to develop comprehensive and rational model by means of inovative technologies for effective purification of soils contaminated with heavy metals

Space of State Vectors in PT Symmetrical Quantum Mechanics

Space of states of PT symmetrical quantum mechanics is examined. Requirement that eigenstates with different eigenvalues must be orthogonal leads to the conclusion that eigenfunctions belong to the space with an indefinite metric. The self consistent expressions for the probability amplitude and average value of operator are suggested. Further specification of space of state vectors yield the superselection rule, redefining notion of the superposition principle. The expression for the probability current density, satisfying equation of continuity and vanishing for the bound state, is proposed.Comment: Revised version, explicit expressions for average values and probability amplitude adde