The two Josephson junction flux qubit with large tunneling amplitude

In this paper we discuss solid-state nanoelectronic realizations of Josephson flux qubits with large tunneling amplitude between the two macroscopic states. The latter can be controlled via the height and wells form of the potential barrier, which is determined by quantum-state engineering of the flux qubit circuit. The simplest circuit of the flux qubit is a superconducting loop interrupted by a Josephson nanoscale tunnel junction. The tunneling amplitude between two macroscopically different states can be essentially increased, by engineering of the qubit circuit, if tunnel junction is replaced by a ScS contact. However, only Josephson tunnel junctions are particularly suitable for large-scale integration circuits and quantum detectors with preset-day technology. To overcome this difficulty we consider here the flux qubit with high-level energy separation between "ground" and "excited" states, which consists of a superconducting loop with two low-capacitance Josephson tunnel junctions in series. We demonstrate that for real parameters of resonant superposition between the two macroscopic states the tunneling amplitude can reach values greater than 1K. Analytical results for the tunneling amplitude obtained within semiclassical approximation by instanton technique show good correlation with a numerical solution.Comment: 8 pages, 4 figure

Competition between Two Kinds of Correlations in Literary Texts

A theory of additive Markov chains with long-range memory is used for description of correlation properties of coarse-grained literary texts. The complex structure of the correlations in texts is revealed. Antipersistent correlations at small distances, L 300 define this nontrivial structure. For some concrete examples of literary texts, the memory functions are obtained and their power-law behavior at long distances is disclosed. This property is shown to be a cause of self-similarity of texts with respect to the decimation procedure.Comment: 7 pages, 7 figures, Submitted to Physica

Комп’ютерне моделювання характеристик одноелектронних транзисторів

Proposed methods of modeling of electrical and temperature characteristics of single-electrontransistor for providing information to system of computer-aided design Electronics Workbench.Analyzed dependence in current-voltage characteristics of nano-device trough values of temperature andoperating modeРазработаны методы моделирования электрических и температурных характеристик одноэлектронного транзистора для информационного обеспечения системы автоматизированного схемотехническогопроектирования Electronics Workbench. Проанализирована зависимость вольт-амперных характеристик наноприбора от влияния температуры и рабочего режимаРозроблено методи моделювання електричних та температурних характеристик одноелектронного транзистора для інформаційного забезпечення системи автоматизованого схемотехнічного проектування Electronics Workbench. Проаналізовано залежність вольт-амперних характеристик наноприладу від впливу температури таробочого режим

Signum Function Method for Generation of Correlated Dichotomic Chains

We analyze the signum-generation method for creating random dichotomic sequences with prescribed correlation properties. The method is based on a binary mapping of the convolution of continuous random numbers with some function originated from the Fourier transform of a binary correlator. The goal of our study is to reveal conditions under which one can construct binary sequences with a given pair correlator. Our results can be used in the construction of superlattices and waveguides with selective transport properties.Comment: 14 pages, 7 figure

Memory functions and Correlations in Additive Binary Markov Chains

A theory of additive Markov chains with long-range memory, proposed earlier in Phys. Rev. E 68, 06117 (2003), is developed and used to describe statistical properties of long-range correlated systems. The convenient characteristics of such systems, a memory function, and its relation to the correlation properties of the systems are examined. Various methods for finding the memory function via the correlation function are proposed. The inverse problem (calculation of the correlation function by means of the prescribed memory function) is also solved. This is demonstrated for the analytically solvable model of the system with a step-wise memory function.Comment: 11 pages, 5 figure