148 research outputs found
On insertion-deletion systems over relational words
We introduce a new notion of a relational word as a finite totally ordered
set of positions endowed with three binary relations that describe which
positions are labeled by equal data, by unequal data and those having an
undefined relation between their labels. We define the operations of insertion
and deletion on relational words generalizing corresponding operations on
strings. We prove that the transitive and reflexive closure of these operations
has a decidable membership problem for the case of short insertion-deletion
rules (of size two/three and three/two). At the same time, we show that in the
general case such systems can produce a coding of any recursively enumerable
language leading to undecidabilty of reachability questions.Comment: 24 pages, 8 figure
Thermalization of coupled atom-light states in the presence of optical collisions
The interaction of a two-level atomic ensemble with a quantized single mode
electromagnetic field in the presence of optical collisions (OC) is
investigated both theoretically and experimentally. The main accent is made on
achieving thermal equilibrium for coupled atom-light states (in particular
dressed states). We propose a model of atomic dressed state thermalization that
accounts for the evolution of the pseudo-spin Bloch vector components and
characterize the essential role of the spontaneous emission rate in the
thermalization process. Our model shows that the time of thermalization of the
coupled atom-light states strictly depends on the ratio of the detuning and the
resonant Rabi frequency. The predicted time of thermalization is in the
nanosecond domain and about ten times shorter than the natural lifetime at full
optical power in our experiment. Experimentally we are investigating the
interaction of the optical field with rubidium atoms in an ultra-high pressure
buffer gas cell under the condition of large atom-field detuning comparable to
the thermal energy in frequency units. In particular, an observed detuning
dependence of the saturated lineshape is interpreted as evidence for thermal
equilibrium of coupled atom-light states. A significant modification of
sideband intensity weights is predicted and obtained in this case as well.Comment: 14 pages, 12 figures; the content was edite
High temperature phase transition in the coupled atom-light system in the presence of optical collisions
The problem of photonic phase transition for the system of a two-level atomic
ensemble interacting with a quantized single-mode electromagnetic field in the
presence of optical collisions (OC) is considered. We have shown that for large
and negative atom-field detuning a photonic field exhibits high temperature
second order phase transition to superradiant state under thermalization
condition for coupled atom-light states. Such a transition can be connected
with superfluid (coherent) properties of photon-like low branch (LB)
polaritons. We discuss the application of metallic cylindrical waveguide for
observing predicted effects.Comment: 8 pages, 2 figure
Hydrogen atom in crossed external fields reexemined by the moment method
Recurrence relations of perturbation theory for hydrogen ground state are
obtained. With their aid polarizabilities in constant perpendicular electric
and magnetic fields are computed up to 80th order. The high orders asymptotic
is compared with its quasiclassical estimate. For the case of arbitrary mutual
orientation of external fields a general sixth order formula is given.Comment: 11 pages, LaTeX, 2 figures (eps
A spectral line shape analysis of motional stark effect spectra
12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France)Recent observations of MSE spectra carried out on Tore-Supra show discrepancies between experimental and theoretical intensities calculated at equilibrium. We present here a kinetic model, based on the selectivity of excitation cross sections of Stark states in the parabolic basis. Redistribution due to ion-atom collisions among Stark states of level n=3 allow to calculate the population of Stark states. This model permits to improve significantly the agreement between measured and calculated MSE spectra
High orders of the perturbation theory for hydrogen atom in magnetic field
The states of hydrogen atom with principal quantum number and zero
magnetic quantum number in constant homogeneous magnetic field are
considered. The coefficients of energy eigenvalues expansion up to 75th order
in powers of are obtained for these states. The series for energy
eigenvalues and wave functions are summed up to values of the order
of atomic magnetic field. The calculations are based on generalization of the
moment method, which may be used in other cases of the hydrogen atom
perturbation by a polynomial in coordinates potential.Comment: 16 pages, LaTeX, 6 figures (ps, eps
Coherent information analysis of quantum channels in simple quantum systems
The coherent information concept is used to analyze a variety of simple
quantum systems. Coherent information was calculated for the information decay
in a two-level atom in the presence of an external resonant field, for the
information exchange between two coupled two-level atoms, and for the
information transfer from a two-level atom to another atom and to a photon
field. The coherent information is shown to be equal to zero for all
full-measurement procedures, but it completely retains its original value for
quantum duplication. Transmission of information from one open subsystem to
another one in the entire closed system is analyzed to learn quantum
information about the forbidden atomic transition via a dipole active
transition of the same atom. It is argued that coherent information can be used
effectively to quantify the information channels in physical systems where
quantum coherence plays an important role.Comment: 24 pages, 7 figs; Final versiob after minor changes, title changed;
to be published in Phys. Rev. A, September 200
Non-adiabatic Semiclassical Dressed States
We introduce non-adiabatic semiclassical dressed states for a quantum system
interacting with an electromagnetic field of variable amplitude and phase, and
presence of dumping. We also introduce a generalized adiabatic condition, which
allows finding of closed form solution for the dressed states. The influence of
the non-adiabatic factors on the dressed states due to the amplitude and phase
field variations and dumping has been found.Comment: 11 pages, 1 figur
Influence of non-local thermodynamic equilibrium and Zeeman effects on magnetic equilibrium reconstruction using spectral motional Stark effect diagnostic
The Motional Stark Effect (MSE) diagnostic is a well established technique to infer the local internal magnetic field in fusion plasmas. In this paper, the existing forward model which describes the MSE data is extended by the Zeeman effect, fine-structure, and relativistic corrections in the interpretation of the MSE spectra for different experimental conditions at the tokamak ASDEX Upgrade. The contribution of the non-Local Thermodynamic Equilibrium (non-LTE) populations among the magnetic sub-levels and the Zeeman effect on the derived plasma parameters is different. The obtained pitch angle is changed by 3Β°β¦4Β° and by 0.5Β°β¦1Β° including the non-LTE and the Zeeman effects into the standard statistical MSE model. The total correction is about 4Β°. Moreover, the variation of the magnetic field strength is significantly changed by 2.2% due to the Zeeman effect only. While the data on the derived pitch angle still could not be tested against the other diagnostics, the results from an equilibrium reconstruction solver confirm the obtained values for magnetic field strength
ΠΡΠ±ΠΎΡ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠ²Π½ΡΡ Π³Π΅ΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΈΡ ΠΏΡΠΈΠ·Π½Π°ΠΊΠΎΠ² ΡΠ΄Π΅Ρ ΠΊΠ»Π΅ΡΠΎΠΊ Π½Π° Π»ΡΠΌΠΈΠ½Π΅ΡΡΠ΅Π½ΡΠ½ΡΡ ΠΈΠ·ΠΎΠ±ΡΠ°ΠΆΠ΅Π½ΠΈΡΡ ΡΠ°ΠΊΠΎΠ²ΡΡ ΠΊΠ»Π΅ΡΠΎΠΊ
The methods of geometric informative features selection of nuclei on fluorescent images of cancer cells are considered. During the survey, a review of existing geometric features was carried out, including both the signs of rotation resisted shape and displacement of the image, as well as signs of location in space. For the selection of characteristics, the methods were used: median, correlation with calculation of the Pearson correlation coefficient, correlation with calculation of the Spearman correlation coefficient, logistic regression model, random forest with CART trees and Gini criterion, random forest with CART trees and error minimization criterion. As a result of the investigation 11 characteristics were selected from 59 features, the quality of classification and time costs were calculated depending on the number of features for describing the objects. The use of 11 features is sufficient for the accuracy of classification as it allows to reduce time costs in 2,3 times.Π Π°ΡΡΠΌΠΎΡΡΠ΅Π½Ρ ΠΌΠ΅ΡΠΎΠ΄Ρ ΠΎΡΠ±ΠΎΡΠ° ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠ²Π½ΡΡ
ΠΏΡΠΈΠ·Π½Π°ΠΊΠΎΠ² Π΄Π»Ρ Π²ΡΠ΄Π΅Π»Π΅Π½ΠΈΡ Π³Π΅ΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΏΡΠΈΠ·Π½Π°ΠΊΠΎΠ² ΠΏΡΠΈ ΠΎΠΏΠΈΡΠ°Π½ΠΈΠΈ ΡΠ΄Π΅Ρ Π½Π° Π»ΡΠΌΠΈΠ½Π΅ΡΡΠ΅Π½ΡΠ½ΡΡ
ΠΈΠ·ΠΎΠ±ΡΠ°ΠΆΠ΅Π½ΠΈΡΡ
ΡΠ°ΠΊΠΎΠ²ΡΡ
ΠΊΠ»Π΅ΡΠΎΠΊ. ΠΡΠΏΠΎΠ»Π½Π΅Π½ ΠΎΠ±Π·ΠΎΡ ΡΡΡΠ΅ΡΡΠ²ΡΡΡΠΈΡ
Π³Π΅ΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΏΡΠΈΠ·Π½Π°ΠΊΠΎΠ², ΠΊΠΎΡΠΎΡΡΠΉ Π²ΠΊΠ»ΡΡΠ°Π΅Ρ Π² ΡΠ΅Π±Ρ ΠΊΠ°ΠΊ ΠΏΡΠΈΠ·Π½Π°ΠΊΠΈ ΡΠΎΡΠΌΡ, ΡΡΡΠΎΠΉΡΠΈΠ²ΡΠ΅ ΠΊ ΠΏΠΎΠ²ΠΎΡΠΎΡΡ ΠΈ ΠΏΠ΅ΡΠ΅ΠΌΠ΅ΡΠ΅Π½ΠΈΡ ΠΈΠ·ΠΎΠ±ΡΠ°ΠΆΠ΅Π½ΠΈΡ, ΡΠ°ΠΊ ΠΈ ΠΏΡΠΈΠ·Π½Π°ΠΊΠΈ ΡΠ°ΡΠΏΠΎΠ»ΠΎΠΆΠ΅Π½ΠΈΡ Π² ΠΏΡΠΎΡΡΡΠ°Π½ΡΡΠ²Π΅. ΠΠ»Ρ ΠΎΡΠ±ΠΎΡΠ° Π½Π°ΠΈΠ±ΠΎΠ»Π΅Π΅ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠ²Π½ΡΡ
ΠΏΡΠΈΠ·Π½Π°ΠΊΠΎΠ² ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½Ρ ΡΠ΅ΡΡΡ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ²: ΠΌΠ΅Π΄ΠΈΠ°Π½Π½ΡΠΉ, ΠΊΠΎΡΡΠ΅Π»ΡΡΠΈΠΎΠ½Π½ΡΠΉ Ρ ΡΠ°ΡΡΠ΅ΡΠΎΠΌ ΠΊΠΎΡΡΡΠΈΡΠΈΠ΅Π½ΡΠ° ΠΊΠΎΡΡΠ΅Π»ΡΡΠΈΠΈ ΠΏΠΎ ΠΠΈΡΡΠΎΠ½Ρ, ΠΊΠΎΡΡΠ΅Π»ΡΡΠΈΠΎΠ½Π½ΡΠΉ Ρ ΡΠ°ΡΡΠ΅ΡΠΎΠΌ ΠΊΠΎΡΡΡΠΈΡΠΈΠ΅Π½ΡΠ° ΠΊΠΎΡΡΠ΅Π»ΡΡΠΈΠΈ ΠΏΠΎ Π‘ΠΏΠΈΡΠΌΠ΅Π½Ρ, ΠΌΠ΅ΡΠΎΠ΄ Π»ΠΎΠ³ΠΈΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠ΅Π³ΡΠ΅ΡΡΠΈΠΈ, ΡΠ»ΡΡΠ°ΠΉΠ½ΠΎΠ³ΠΎ Π»Π΅ΡΠ° Ρ CART-Π΄Π΅ΡΠ΅Π²ΡΡΠΌΠΈ ΠΈ ΠΊΡΠΈΡΠ΅ΡΠΈΠ΅ΠΌ Gini, ΡΠ»ΡΡΠ°ΠΉΠ½ΠΎΠ³ΠΎ Π»Π΅ΡΠ° Ρ CART-Π΄Π΅ΡΠ΅Π²ΡΡΠΌΠΈ ΠΈ ΠΊΡΠΈΡΠ΅ΡΠΈΠ΅ΠΌ ΠΌΠΈΠ½ΠΈΠΌΠΈΠ·Π°ΡΠΈΠΈ ΠΎΡΠΈΠ±ΠΊΠΈ. Π ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠ΅ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΠΈΠ· 59 ΠΏΡΠΈΠ·Π½Π°ΠΊΠΎΠ² ΠΎΡΠΎΠ±ΡΠ°Π½Ρ 11 Π½Π°ΠΈΠ±ΠΎΠ»Π΅Π΅ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠ²Π½ΡΡ
, Π²ΡΠΏΠΎΠ»Π½Π΅Π½ Π°Π½Π°Π»ΠΈΠ· ΠΊΠ°ΡΠ΅ΡΡΠ²Π° ΠΊΠ»Π°ΡΡΠΈΡΠΈΠΊΠ°ΡΠΈΠΈ Ρ ΠΏΠΎΠΌΠΎΡΡΡ ΠΌΠ΅ΡΠΎΠ΄Π° ΡΠ»ΡΡΠ°ΠΉΠ½ΠΎΠ³ΠΎ Π»Π΅ΡΠ° ΠΈ ΡΠ°ΡΡΡΠΈΡΠ°Π½Ρ Π²ΡΠ΅ΠΌΠ΅Π½Π½ΡΠ΅ Π·Π°ΡΡΠ°ΡΡ Π² Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ ΠΎΡ ΠΊΠΎΠ»ΠΈΡΠ΅ΡΡΠ²Π° ΠΏΡΠΈΠ·Π½Π°ΠΊΠΎΠ² Π΄Π»Ρ ΠΎΠΏΠΈΡΠ°Π½ΠΈΡ ΠΎΠ±ΡΠ΅ΠΊΡΠΎΠ². ΠΠ»Ρ ΠΌΠ΅ΡΠΎΠ΄Π° ΡΠ»ΡΡΠ°ΠΉΠ½ΠΎΠ³ΠΎ Π»Π΅ΡΠ° ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ 11 ΠΏΡΠΈΠ·Π½Π°ΠΊΠΎΠ² ΡΠ²Π»ΡΠ΅ΡΡΡ Π΄ΠΎΡΡΠ°ΡΠΎΡΠ½ΡΠΌ ΠΏΠΎ ΡΠΎΡΠ½ΠΎΡΡΠΈ ΠΊΠ»Π°ΡΡΠΈΡΠΈΠΊΠ°ΡΠΈΠΈ ΠΈ ΠΏΠΎΠ·Π²ΠΎΠ»ΡΠ΅Ρ ΡΠ½ΠΈΠ·ΠΈΡΡ Π²ΡΠ΅ΠΌΠ΅Π½Π½ΡΠ΅ Π·Π°ΡΡΠ°ΡΡ Π² 2,3 ΡΠ°Π·Π°
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