41 research outputs found
Quantum Chaos in the Yang-Mills-Higgs System at Finite Temperature
The quantum chaos in the finite-temperature Yang-Mills-Higgs system is
studied. The energy spectrum of a spatially homogeneous SU(2) Yang-Mills-Higgs
is calculated within thermofield dynamics. Level statistics of the spectra is
studied by plotting nearest-level spacing distribution histograms. It is found
that finite temperature effects lead to a strengthening of chaotic effects,
i.e. spectrum which has Poissonian distribution at zero temperature has
Gaussian distribution at finite-temperature.Comment: 6 pages, 5 figures, Revte
Quantum Transport in Ladder-Type Networks: Role of nonlinearity, topology and spin
We investigate quantum transport of electrons, phase solitons, etc. through
mesoscopic networks of zero-dimensional quantum dots. Straight and circular
ladders are chosen as networks with each coupled with three semi-infinite leads
(with one incoming and the other two outgoing). Two transmission probabilities
(TPs) as a function of the incident energy show a transition from
anti-phase aperiodic to degenerate periodic spectra at the critical energy
which is determined by a bifurcation point of the bulk energy
dispersions. TPs of the circular ladder depend only on the parity of the
winding number. Introduction of a single missing bond (MB) or missing step
doubles the period of the periodic spectra at . Shift of
the MB by lattice constant results in a striking switching effect at
. In the presence of the electric-field induced spin-orbit
interaction (SOI), an obvious spin filtering occurs against the
spin-unpolarized injection. Against the spin-polarized injection, on the other
hand, the spin transport shows spin-flip (magnetization reversal) oscillations
with respect to SOI. We also show a role of soliton in the context of its
transport through the ladder networks.Comment: 10 pages, 16 figure
ASSESSMENT OF POTENTIAL RADIATION HAZARD OF THE FORMER URANIUM FACILITIES FOR THE POPULATION OF THE ISTIKLOL CITY OF THE REPUBLIC OF TADZHIKISTAN
The article presents the results of alpha, gamma spectrometric analyzes of samples, dosimetry, radon monitoring of the estimated areas in the Istiklol city. It has been established that the specific activity of radionuclides for uranium and radium in the tailing materials are in the range: 1405 ā 2140, 5935 ā 9843 Bq / kg, respectively. Based on the results of the monitoring of gamma radiation and radon volume activity at Istiklol city sites, it has been established that gamma radiation ambient equivalent dose rate varies from 0.52 to 1.78 Ī¼Sv / h, and radon volume activity in air ranges from 20 and 45 Bq / m3. It is shown that the radon concentration in the air above the surface of tailings is not high. However, the exhalation of radon from the soil surface of all the tailings dumps examined is above the standard (1 Bq / (m2Ā·s). The results of measurements of radon volume activity in the air of residential buildings and facilities located on the territory of Istiklol city have shown that the value of radon volume activity is within the limits of 44 ā 195 Bq / m3. A high value of radon volume activity is noted in the former dilapidated plant (1319 Bq / m3). Gamma and alpha spectrometric studies revealed that the average valuesĀ Ā of the activity concentration of uranium and radium in the soils for tailings and the pit are for 234U ā 65365 Bq / kg, for 238U ā 50295 Bq / kg, and for 226Ra ā 3800 Bq / kg. To estimate the doses of population irradiation via the water pathway were taken the average valuesĀ Ā of the volumetric activity of 234U, 238U, 226Ra in the waters. Maximum valuesĀ Ā of volumetric activity of radionuclides were observed in samples of drainage water, Bq / m3: 234U ā 530000, 238U ā 390000, 226Ra ā 185. To calculate the contributions of various radiation factors to an additional annual dose of irradiation, the population was divided into four hypothetical groups. The time duration of stay of various hypothetical population groups in the areas of potential irradiation, radiation dose due to water use from contaminated water sources and additional factors in Istiklol were taken into account.The main contributor to the additional radiation dose received by hypothetical population groups is external irradiation during the stay on the territory of the FBR and tailing dumps, and internal irradiation due to the use of contaminated water