1,497 research outputs found
Composite Dark Matter and Puzzles of Dark Matter Searches
Positive results of dark matter searches in DAMA/NaI and DAMA/LIBRA
experiments, being put together with the results of other groups, can imply
nontrivial particle physics solutions for cosmological dark matter. Stable
particles with charge -2, bound with primordial helium in O-helium "atoms"
(OHe), represent a specific Warmer than Cold nuclear-interacting form of dark
matter. Slowed down in the terrestrial matter, OHe is elusive for direct
methods of underground Dark matter detection used in cryogenic experiments.
However radiative capture of OHe by Na and I nuclei can lead to annual
variations of energy release in the interval of energy 2-5 keV in DAMA/NaI and
DAMA/LIBRA experiments.Comment: 10 pages, 2 figures, Invited contribution to proceeding of the 4th
International Workshop on Astronomy and Relativistic Astrophysics (IWARA09
Conductance of p-n-p graphene structures with 'air-bridge' top gates
We have fabricated graphene devices with a top gate separated from the
graphene layer by an air gap--a design which does not decrease the mobility of
charge carriers under the gate. This gate is used to realise p-n-p structures
where the conducting properties of chiral carriers are studied. The band
profile of the structures is calculated taking into account the specifics of
the graphene density of states and is used to find the resistance of the p-n
junctions expected for chiral carriers. We show that ballistic p-n junctions
have larger resistance than diffusive ones. This is caused by suppressed
transmission of chiral carriers at angles away from the normal to the junction.Comment: to be published in Nano Letter
Internet as a factor in the developnet of extremism in the youth environment
Π‘ΡΠ°ΡΡΡ ΠΏΠΎΡΠ²ΡΡΠ΅Π½Π° ΠΈΠ·ΡΡΠ΅Π½ΠΈΡ ΠΠ½ΡΠ΅ΡΠ½Π΅ΡΠ° ΠΊΠ°ΠΊ ΡΠ°ΠΊΡΠΎΡΠ°, Π²Π»ΠΈΡΡΡΠ΅Π³ΠΎ Π½Π° ΡΠ°Π·Π²ΠΈΡΠΈΠ΅ ΡΠΊΡΡΡΠ΅ΠΌΠΈΠ·ΠΌΠ°. ΠΠ° ΠΎΡΠ½ΠΎΠ²Π΅ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΎΠ² ΡΠΌΠΏΠΈΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ Π°Π²ΡΠΎΡ ΠΏΡΠΈΡ
ΠΎΠ΄ΠΈΡ ΠΊ Π²ΡΠ²ΠΎΠ΄Ρ, ΡΡΠΎ ΡΠΎΡΠΈΠ°Π»ΡΠ½Π°Ρ ΡΠ΅ΡΡ ΠΠΠΎΠ½ΡΠ°ΠΊΡΠ΅ ΡΠ²Π»ΡΠ΅ΡΡΡ ΡΠ°ΠΌΠΎΠΉ ΡΠ°ΡΡΠΎ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΠ΅ΠΌΠΎΠΉ ΠΏΠ»ΠΎΡΠ°Π΄ΠΊΠΎΠΉ Π΄Π»Ρ Π²ΠΎΠ·Π΄Π΅ΠΉΡΡΠ²ΠΈΡ ΡΠΊΡΡΡΠ΅ΠΌΠΈΡΡΠΎΠ² Π½Π° ΠΌΠΎΠ»ΠΎΠ΄Π΅ΠΆΡ.The article considers the Internet as the factor which influence on developing of extremism. Based on the results of empirical research the author concludes that a social network as VKontakte is frequently used for exstremistβs influence on the youth
Weak localisation in bilayer graphene
We have performed the first experimental investigation of quantum
interference corrections to the conductivity of a bilayer graphene structure. A
negative magnetoresistance - a signature of weak localisation - is observed at
different carrier densities, including the electro-neutrality region. It is
very different, however, from the weak localisation in conventional
two-dimensional systems. We show that it is controlled not only by the
dephasing time, but also by different elastic processes that break the
effective time-reversal symmetry and provide invervalley scattering.Comment: 4 pages, 4 figures (to be published in PRL
Π‘Π²ΠΎΠΉΡΡΠ²Π° Π³Π°ΡΠΌΠΎΠ½ΠΈΡΠ΅ΡΠΊΠΈΡ ΠΈ ΡΠΎΡΡΠ°Π²Π½ΡΡ ΠΏΠΎΠ»ΡΠ²ΠΎΠ»Π½, ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅ ΠΈΠ½ΡΠ΅ΡΠ²Π°Π»Π° ΡΠ°Π²Π½ΠΎΠΌΠ΅ΡΠ½ΠΎΠΉ Π΄ΠΈΡΠΊΡΠ΅ΡΠΈΠ·Π°ΡΠΈΠΈ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ ΡΠΈΡΡΠΎΠ²ΡΡ ΡΠΈΠ³Π½Π°Π»ΡΠ½ΡΡ ΠΏΡΠΎΡΠ΅ΡΡΠΎΡΠΎΠ²
ΠΡΠΈ ΠΏΠΎΡΡΡΠΎΠ΅Π½ΠΈΠΈ Π°Π²ΡΠΎΠ½ΠΎΠΌΠ½ΡΡ
ΡΠΈΡΡΠ΅ΠΌ ΡΠ΅Π°Π»ΡΠ½ΠΎΠ³ΠΎ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ (Π‘Π Π) Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎ ΡΠ΅ΡΠ°ΡΡ Π·Π°Π΄Π°ΡΡ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠΉ ΠΌΠ½ΠΎΠ³ΠΎΠ·Π°Π΄Π°ΡΠ½ΠΎΠΉ Π·Π°Π³ΡΡΠ·ΠΊΠΈ ΡΡΠ΄Π° ΠΏΠ°ΡΠ°Π»Π»Π΅Π»ΡΠ½ΠΎ ΡΡΠ½ΠΊΡΠΈΠΎΠ½ΠΈΡΡΡΡΠΈΡ
ΡΠΈΡΡΠΎΠ²ΡΡ
ΡΠΈΠ³Π½Π°Π»ΡΠ½ΡΡ
ΠΏΡΠΎΡΠ΅ΡΡΠΎΡΠΎΠ². ΠΠ΄Π½ΠΈΠΌ ΠΈΠ· ΡΠ΅Π·Π΅ΡΠ²ΠΎΠ² Π΄ΠΎΡΡΠΈΠΆΠ΅Π½ΠΈΡ Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎΠ³ΠΎ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠ° Π²ΡΡΡΡΠΏΠ°Π΅Ρ ΡΠ΅Π°Π»ΠΈΠ·Π°ΡΠΈΡ Π²ΡΠ±ΠΎΡΠΎΠΊ ΠΈΠ· ΡΠΈΠ³Π½Π°Π»ΠΎΠ² Π΄Π°ΡΡΠΈΠΊΠΎΠ² ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΈ ΠΎ Π²Π΅Π»ΠΈΡΠΈΠ½Π΅ ΡΠΈΠ³Π½Π°Π»Π° Π½Π°ΠΈΠ±ΠΎΠ»Π΅Π΅ ΡΠ΅Π΄ΠΊΠΎ Π²ΠΎ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ. ΠΡΠΈ ΡΡΠΎΠΌ Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠΈΠ²Π°ΡΡ Π»ΠΈΠ½Π΅ΠΉΠ½ΡΡ ΠΈΠ»ΠΈ ΡΡΡΠΏΠ΅Π½ΡΠ°ΡΡΡ Π°ΠΏΠΏΡΠΎΠΊΡΠΈΠΌΠ°ΡΠΈΡ ΡΠΈΠ³Π½Π°Π»Π° ΠΏΠΎ Π²ΡΠ±ΠΎΡΠΊΠ°ΠΌ Ρ Π΄ΠΎΠΏΡΡΡΠΈΠΌΠΎΠΉ ΠΏΠΎΠ³ΡΠ΅ΡΠ½ΠΎΡΡΡΡ Π²ΠΎΡΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΈΡ. ΠΠ΄Π½ΠΎΠΉ ΠΈΠ· ΡΠΈΡΡΠ΅ΠΌΠ½ΡΡ
Π·Π°Π΄Π°Ρ ΡΡΠΈΡ
ΠΏΡΠΎΡΠ΅ΡΡΠΎΡΠΎΠ² ΡΠ²Π»ΡΠ΅ΡΡΡ ΡΠΈΠ»ΡΡΡΠ°ΡΠΈΡ ΡΠΈΠ³Π½Π°Π»ΠΎΠ² ΠΈΠ»ΠΈ ΠΎΠ³ΡΠ°Π½ΠΈΡΠ΅Π½ΠΈΠ΅ ΡΠΏΠ΅ΠΊΡΡΠ° Π΄ΠΎ ΡΠ°ΡΡΠΎΡΡ ΡΡΠ΅Π·Π°. ΠΡΠ»ΠΈΡΠΈΡΠ΅Π»ΡΠ½ΠΎΠΉ ΠΎΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΡΡ ΠΏΡΠ΅Π΄Π»Π°Π³Π°Π΅ΠΌΠΎΠ³ΠΎ Π² ΡΡΠ°ΡΡΠ΅ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄Π° ΡΠ²Π»ΡΠ΅ΡΡΡ Π²ΡΠΏΠΎΠ»Π½Π΅Π½ΠΈΠ΅ ΡΡΠ»ΠΎΠ²ΠΈΡ: Π΅ΡΠ»ΠΈ ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΠ΅ ΡΡΠΎΠΉ ΡΠ°ΡΡΠΎΡΡ Π·Π°ΡΡΡΠ΄Π½Π΅Π½ΠΎ (Π½Π°ΠΏΡΠΈΠΌΠ΅Ρ, Π² ΡΠ»Π΅ΠΊΡΡΠΎΠΌΠ΅Ρ
Π°Π½ΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΡΠ΅Π΄ΡΡΠ²Π°Ρ
Π‘Π Π), ΡΠΎ Π΄Π»Ρ ΡΠ°ΠΊΠΈΡ
ΡΠΈΠ³Π½Π°Π»ΠΎΠ² ΠΏΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½ΠΎ ΡΠΎΠ³Π»Π°ΡΠΎΠ²ΡΠ²Π°ΡΡ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΡΠ΅ Π²Π΅Π»ΠΈΡΠΈΠ½Ρ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² Π³Π°ΡΠΌΠΎΠ½ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΏΠΎΠ»ΡΠ²ΠΎΠ»Π½Ρ: ΠΏΠΎΠ³ΡΠ΅ΡΠ½ΠΎΡΡΡ Π°ΠΏΠΏΡΠΎΠΊΡΠΈΠΌΠ°ΡΠΈΠΈ, ΡΠΊΠΎΡΠΎΡΡΡ ΠΈ ΡΡΠΊΠΎΡΠ΅Π½ΠΈΠ΅. ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠ΅ ΠΎΡΠΊΡΡΠ²Π°Π΅Ρ ΠΏΠ΅ΡΡΠΏΠ΅ΠΊΡΠΈΠ²Ρ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΡ Π½ΠΎΠ²ΡΡ
ΠΏΠΎΠ΄Ρ
ΠΎΠ΄ΠΎΠ² ΠΏΠΎ Π΄ΠΈΡΠΊΡΠ΅ΡΠΈΠ·Π°ΡΠΈΠΈ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ ΡΠΈΠ³Π½Π°Π»ΠΎΠ² Π² Π°ΠΌΠΏΠ»ΠΈΡΡΠ΄Π½ΠΎ-Π²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠΉ ΠΎΠ±Π»Π°ΡΡΠΈ ΠΈ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅ Π΄Π»Ρ ΡΠ°ΠΊΠΈΡ
ΡΠΈΠ³Π½Π°Π»ΠΎΠ² ΡΠΊΠ²ΠΈΠ²Π°Π»Π΅Π½ΡΠ½ΠΎΠΉ ΡΠ°ΡΡΠΎΡΡ ΡΡΠ΅Π·Π° ΡΠΏΠ΅ΠΊΡΡΠ° ΡΠΈΠ³Π½Π°Π»Π°. Π Π½Π°ΡΡΠΎΡΡΠ΅ΠΉ ΡΡΠ°ΡΡΠ΅ ΠΏΠΎΠ»ΡΡΠ΅Π½Ρ Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ Π²Π΅Π»ΠΈΡΠΈΠ½Ρ Π΅Π΄ΠΈΠ½ΠΈΡΡ ΡΠΈΡΡΠ΅ΠΌΠ½ΠΎΠ³ΠΎ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ Π²Π²ΠΎΠ΄Π°-Π²ΡΠ²ΠΎΠ΄Π° Π΄Π°Π½Π½ΡΡ
ΠΎΡ ΡΡΠ΅ΠΏΠ΅Π½ΠΈ ΡΠΎΠ³Π»Π°ΡΠΎΠ²Π°Π½ΠΈΡ ΠΌΠ΅ΠΆΠ΄Ρ ΡΠΎΠ±ΠΎΠΉ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΡΡ
Π²Π΅Π»ΠΈΡΠΈΠ½ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΡΠΈΠ³Π½Π°Π»Π°. ΠΠ°ΡΠ΅ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠ°Ρ ΠΌΠΎΠ΄Π΅Π»Ρ ΡΠΊΡΡΡΠ΅ΠΌΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΠ²Π΅Π΄Π΅Π½ΠΈΡ ΡΠΈΠ³Π½Π°Π»Π° ΠΌΠ΅ΠΆΠ΄Ρ Π΄Π²ΡΠΌΡ ΡΠΎΡΠ΅Π΄Π½ΠΈΠΌΠΈ Π²ΡΠ±ΠΎΡΠΊΠ°ΠΌΠΈ Π·Π°Π΄Π°Π½Π° Π² Π²ΠΈΠ΄Π΅ Π³Π°ΡΠΌΠΎΠ½ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΏΠΎΠ»ΡΠ²ΠΎΠ»Π½Ρ. ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠ΅ ΡΠ°ΡΠΏΡΠΎΡΡΡΠ°Π½Π΅Π½ΠΎ ΡΠ°ΠΊΠΆΠ΅ Π½Π° Π²ΡΠΏΡΠΊΠ»ΡΠ΅ ΡΠΎΡΡΠ°Π²Π½ΡΠ΅ Π³Π°ΡΠΌΠΎΠ½ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΡΠ½ΠΊΡΠΈΠΈ, ΠΏΠΎ ΠΊΠΎΡΠΎΡΡΠΌ ΡΠΈΠ³Π½Π°Π» ΠΌΠΎΠΆΠ΅Ρ ΠΎΡΠΊΠ»ΠΎΠ½ΡΡΡΡΡ ΠΎΡ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΎΠ² Π»ΠΈΠ½Π΅ΠΉΠ½ΠΎΠΉ ΠΈΠ»ΠΈ ΡΡΡΠΏΠ΅Π½ΡΠ°ΡΠΎΠΉ Π°ΠΏΠΏΡΠΎΠΊΡΠΈΠΌΠ°ΡΠΈΠΈ ΡΠΈΠ³Π½Π°Π»Π° ΠΏΠΎ ΡΡΠΈΠΌ Π²ΡΠ±ΠΎΡΠΊΠ°ΠΌ. ΠΡΠΎΠ²Π΅Π΄Π΅Π½ΠΎ ΡΡΠ°Π²Π½Π΅Π½ΠΈΠ΅ ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ ΠΏΠΎ Π²Π΅Π»ΠΈΡΠΈΠ½Π΅ ΠΎΡΠ½ΠΎΡΠΈΡΠ΅Π»ΡΠ½ΡΡ
ΠΈΠ½ΡΠ΅ΡΠ²Π°Π»ΠΎΠ² Π΄ΠΈΡΠΊΡΠ΅ΡΠΈΠ·Π°ΡΠΈΠΈ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ, Π·Π°Π²ΠΈΡΡΡΠΈΡ
ΠΎΡ ΡΡΠ΅ΠΏΠ΅Π½ΠΈ ΡΠΎΠ³Π»Π°ΡΠΎΠ²Π°Π½ΠΈΡ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΡΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² Π³Π°ΡΠΌΠΎΠ½ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΏΠΎΠ»ΡΠ²ΠΎΠ»Π½Ρ. ΠΡΠΈ ΡΡΠ°Π²Π½Π΅Π½ΠΈΠΈ, ΠΊΡΠΎΠΌΠ΅ ΡΡΠΈΡ
ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΡΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ², ΡΡΡΠ΅Π½Π° ΡΠ²ΡΠ·Ρ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠΉ ΡΠΊΠΎΡΠΎΡΡΠΈ ΡΠΈΠ³Π½Π°Π»Π° Ρ ΠΏΠΎΠ³ΡΠ΅ΡΠ½ΠΎΡΡΡΡ Π°ΠΏΠΏΡΠΎΠΊΡΠΈΠΌΠ°ΡΠΈΠΈ Π²ΡΠ±ΠΎΡΠΎΠΊ ΡΡΡΠΏΠ΅Π½ΡΠΊΠ°ΠΌΠΈ ΠΈ ΡΠ²ΡΠ·Ρ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΡΠΊΠΎΡΠ΅Π½ΠΈΡ ΡΠΈΠ³Π½Π°Π»Π° Ρ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠΉ ΠΏΠΎΠ³ΡΠ΅ΡΠ½ΠΎΡΡΡΡ Π»ΠΈΠ½Π΅ΠΉΠ½ΠΎΠΉ Π°ΠΏΠΏΡΠΎΠΊΡΠΈΠΌΠ°ΡΠΈΠΈ. Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡΡ ΠΎΠΏΡΠ΅Π΄Π΅Π»ΡΡΡ Π΄Π»ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ ΠΈΠ½ΡΠ΅ΡΠ²Π°Π»ΠΎΠ² ΡΠ°Π²Π½ΠΎΠΌΠ΅ΡΠ½ΠΎΠΉ Π΄ΠΈΡΠΊΡΠ΅ΡΠΈΠ·Π°ΡΠΈΠΈ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ ΡΠΈΠ³Π½Π°Π»Π° ΠΏΠΎ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠ°ΠΌ ΠΎΠ±ΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΠΎΠ±ΡΠ΅ΠΊΡΠ° ΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ, ΠΎΠ±ΠΎΡΠ½ΠΎΠ²ΡΠ²Π°ΡΡ ΡΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎΠ΅ ΡΠ²Π΅Π»ΠΈΡΠ΅Π½ΠΈΠ΅ ΠΈΠ½ΡΠ΅ΡΠ²Π°Π»Π° Π΄ΠΈΡΠΊΡΠ΅ΡΠΈΠ·Π°ΡΠΈΠΈ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ ΠΈΠ»ΠΈ Π°Π½Π°Π»ΠΎΠ³ΠΈΡΠ½ΠΎΠ΅ ΡΠ²Π΅Π»ΠΈΡΠ΅Π½ΠΈΠ΅ ΡΠΈΡΠ»Π° ΡΠ΅ΡΠ°Π΅ΠΌΡΡ
Π·Π°Π΄Π°Ρ Π² Π΅Π΄ΠΈΠ½ΠΈΡΡ ΡΠΈΡΡΠ΅ΠΌΠ½ΠΎΠ³ΠΎ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ
Density of states and zero Landau level probed through capacitance of graphene
We report capacitors in which a finite electronic compressibility of graphene
dominates the electrostatics, resulting in pronounced changes in capacitance as
a function of magnetic field and carrier concentration. The capacitance
measurements have allowed us to accurately map the density of states D, and
compare it against theoretical predictions. Landau oscillations in D are robust
and zero Landau level (LL) can easily be seen at room temperature in moderate
fields. The broadening of LLs is strongly affected by charge inhomogeneity that
leads to zero LL being broader than other levels
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