308 research outputs found
Possible Jahn-Teller effect in Si-inverse layers
Jahn-Teller effect in bivalley Si(100) MOSFET under conditions of quantum
Hall effect at integer filling factors nu=1,2,3 is studied. This system is
described by SU(4) hidden symmetry. At nu=2 static and dynamic lattice
deformation creates an easy-plane anisotropy and antiferromagnetic exchange and
lifts the valley degeneracy. At nu=1,3 Coulomb interaction is essential to
produce weak easy-plane anisotropy. Three phases: ferromagnetic, canted
antiferromagnetic and spin-singlet, have been found. Anisotropy energy of
charged skyrmion excitation in every phase is found.Comment: 8 pages, 4 figure
Thermally excited spin-current in metals with embedded ferromagnetic nanoclusters
We show that a thermally excited spin-current naturally appears in metals
with embedded ferromagnetic nanoclusters. When such materials are subjected to
a magnetic field, a spin current can be generated by a temperature gradient
across the sample as a signature of electron-hole symmetry breaking in a metal
due to the electron spin-flip scattering from polarised magnetic moments. Such
a spin current can be observed via a giant magneto-thermopower which tracks the
polarisation state of the magnetic subsystem and is proportional to the
magnetoresistance. Our theory explains the recent experiment on Co clusters in
copper by S. Serrano-Guisan \textit{et al} [Nature Materials AOP,
doi:10.1038/nmat1713 (2006)
Dynamical regimes of dissipative quantum systems
We reveal several distinct regimes of the relaxation dynamics of a small
quantum system coupled to an environment within the plane of the dissipation
strength and the reservoir temperature. This is achieved by discriminating
between coherent dynamics with damped oscillatory behavior on all time scales,
partially coherent behavior being nonmonotonic at intermediate times but
monotonic at large ones, and purely monotonic incoherent decay. Surprisingly,
elevated temperature can render the system `more coherent' by inducing a
transition from the partially coherent to the coherent regime. This provides a
refined view on the relaxation dynamics of open quantum systems.Comment: 5 pages, 3 figure
Oscillatory dynamics and non-markovian memory in dissipative quantum systems
The nonequilibrium dynamics of a small quantum system coupled to a
dissipative environment is studied. We show that (1) the oscillatory dynamics
close to a coherent-to-incoherent transition is surprisingly different from the
one of the classical damped harmonic oscillator and that (2) non-markovian
memory plays a prominent role in the time evolution after a quantum quench.Comment: 5 pages, 3 figure
Spectral features due to inter-Landau-level transitions in the Raman spectrum of bilayer graphene
We investigate the contribution of the low-energy electronic excitations
towards the Raman spectrum of bilayer graphene for the incoming photon energy
Omega >> 1eV. Starting with the four-band tight-binding model, we derive an
effective scattering amplitude that can be incorporated into the commonly used
two-band approximation. Due to the influence of the high-energy bands, this
effective scattering amplitude is different from the contact interaction
amplitude obtained within the two-band model alone. We then calculate the
spectral density of the inelastic light scattering accompanied by the
excitation of electron-hole pairs in bilayer graphene. In the absence of a
magnetic field, due to the parabolic dispersion of the low-energy bands in a
bilayer crystal, this contribution is constant and in doped structures has a
threshold at twice the Fermi energy. In an external magnetic field, the
dominant Raman-active modes are the n_{-} to n_{+} inter-Landau-level
transitions with crossed polarisation of in/out photons. We estimate the
quantum efficiency of a single n_{-} to n_{+} transition in the magnetic field
of 10T as I_{n_{-} to n_{+}}~10^{-12}.Comment: 7 pages, 3 figures, expanded version published in PR
Overexpression of MRPS18-2 in cancer cell lines results in appearance of multinucleated cells
Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Human mitochondrial ribosomal protein MRPS18-2 (S18-2) is encoded by a cellular gene that is located on the human chromosome 6p21.3. We discovered that overexpression of the S18-2 protein led to immortalization and de-differentiation of primary rat embryonic fibroblasts. Cells showed anchorage-independent growth pattern. Moreover, pathways characteristic for rapidly proliferating cells were upregulated then. It is possible that the S18-2 overexpression induced disturbance in cell cycle regulation. We found that overexpression of S18-2 protein in human cancer cell lines led to an appearance of multinucleated cells in the selected clones.publishersversionPeer reviewe
On E-functions of Semisimple Lie Groups
We develop and describe continuous and discrete transforms of class functions
on a compact semisimple, but not simple, Lie group as their expansions into
series of special functions that are invariant under the action of the even
subgroup of the Weyl group of . We distinguish two cases of even Weyl groups
-- one is the direct product of even Weyl groups of simple components of ,
the second is the full even Weyl group of . The problem is rather simple in
two dimensions. It is much richer in dimensions greater than two -- we describe
in detail transforms of semisimple Lie groups of rank 3.Comment: 17 pages, 2 figure
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