Flavor Mixing, Neutrino Masses and Neutrino Oscillations

We study a model for the mass matrices of the leptons. We are ablte to relate the mass eigenvalues of the charged leptons and of the neutrinos to the mxiing angles and can predict the masses of the neutrinos. We find a normal hierarchy -the masses are 0.004 eV, 0.01 eV and 0.05 eV. The atmospheric mixing angle is given by the mass ratios of the charged leptons and of the neutrinos. We find 38 degrees, consistent with the experiments. The mixing element, connecting the first neutrino with the electron, is found to be 0.05.Comment: 4 page

Possible mechanisms for initiating macroscopic left-right asymmetry in developing organisms

How might systematic left-right (L/R) asymmetry of the body plan originate in multicellular animals (and plants)? Somehow, the microscopic handedness of biological molecules must be brought up to macroscopic scales. Basic symmetry principles suggest that the usual "biological" mechanisms -- diffusion and gene regulation -- are insufficient to implement the "right-hand rule" defining a third body axis from the other two. Instead, on the cellular level, "physical" mechanisms (forces and collective dynamic states) are needed involving the long stiff fibers of the cytoskeleton. I discuss some possible scenarios; only in the case of vertebrate internal organs is the answer currently known (and even that is in dispute).Comment: 9 pp latex, 6 figures. Proc. Landau 100 Memorial Conf. (Chernogolovka, June 2008); to appear AIP Conf. series. (v2: added 4 ref's + revised Sec 2.2.

Statistical physics of dyons and quark confinement

We present a semiclassical approach to the SU(N) Yang--Mills theory whose partition function at nonzero temperatures is approximated by a saddle point -- an ensemble of an infinite number of interacting dyons of N kinds. The ensemble is governed by an exactly solvable 3d quantum field theory, allowing calculation of correlations functions relevant to confinement. We show that known criteria of confinement are satisfied in this semiclassical approximation: (i) the average Polyakov line is zero below some critical temperature, and nonzero above it, (ii) a quark-antiquark pair has linear rising potential energy, (iii) the average spatial Wilson loop falls off exponentially with the area, (iv) N^2 gluons are canceled out from the spectrum, (v) the critical deconfinement temperature is in good agreement with lattice data. Using the same approximation, we find confinement for the exceptional gauge group G(2) and a first-order deconfinement transition, also in agreement with lattice findings.Comment: Invited talk at the Landau Memorial Conference "Advances in Theoretical Physics", June 22-26, 2008, Chernogolovka, to be published in the Proceeding

Neurofeedback Therapy for Enhancing Visual Attention: State-of-the-Art and Challenges

We have witnessed a rapid development of brain-computer interfaces (BCIs) linking the brain to external devices. BCIs can be utilized to treat neurological conditions and even to augment brain functions. BCIs offer a promising treatment for mental disorders, including disorders of attention. Here we review the current state of the art and challenges of attention-based BCIs, with a focus on visual attention. Attention-based BCIs utilize electroencephalograms (EEGs) or other recording techniques to generate neurofeedback, which patients use to improve their attention, a complex cognitive function. Although progress has been made in the studies of neural mechanisms of attention, extraction of attention-related neural signals needed for BCI operations is a difficult problem. To attain good BCI performance, it is important to select the features of neural activity that represent attentional signals. BCI decoding of attention-related activity may be hindered by the presence of different neural signals. Therefore, BCI accuracy can be improved by signal processing algorithms that dissociate signals of interest from irrelevant activities. Notwithstanding recent progress, optimal processing of attentional neural signals remains a fundamental challenge for the development of efficient therapies for disorders of attention

Relativistic magnetotransport in graphene

We study the thermal and electric transport of a fluid of interacting Dirac fermions as they arise in single-layer graphene. We include Coulomb interactions, a dilute density of charged impurities and the presence of a magnetic field to describe both the static and the low frequency response as a function of temperature T and chemical potential mu. In the critical regime mu << T where both bands above and below the Dirac point contribute to transport we find pronounced deviations from Fermi liquid behavior, universal, collision-dominated values for transport coefficients and a cyclotron resonance of collective nature. In the collision-dominated high temperature regime the linear thermoelectric transport coefficients are shown to obey the constraints of relativistic magnetohydrodynamics which we derive microscopically from Boltzmann theory. The latter also allows us to describe the crossover to disorder-dominated Fermi liquid behavior at large doping and low temperatures, as well as the crossover to the ballistic regime at high fields.Comment: Proceedings of the Landau Memorial Conference 200

Coexistence of triplet superconductivity and itinerant ferromagnetism

The triplet superconductivity in $UGe_2$ and $URhGe$ coexists with itinerant ferromagnetism such that in the pressure-temperature phase diagram the whole region occupied by the superconducting state is situated inside a more vast ferromagnetic region. In the same family metal UCoGe the pressure dependent critical lines T_{Curie}(P) and T_{sc}(P) of the ferromagnet and the superconducting phase transitions intersect each other. The two-band multidomain superconducting ferromagnet state arises at temperatures below both of these lines. Here I describe the symmetry and the order parameters of the paramagnet as well of the multidomain ferromagnet superconducting states. The Josephson coupling between two adjacent ferromagnet superconducting domains is discussed.Comment: 6 pages, 1 figure, published in the Proceedings of L.D.Landau 100 years Memorial Conferenc