scholarly journals Deforming Gibbs Factor Using Tsallis q-Exponential with a Complex Parameter: An Ideal Bose Gas Case

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 732
Author(s):  
Andrij Rovenchak
Keyword(s):  
Critical Temperature ◽  
Temperature Dependence ◽  
System Analysis ◽  
Physical Problems ◽  
Occupation Numbers ◽  
Proposed Model ◽  
Quantum Critical Phenomena ◽  
Effective Description ◽  
Numerical Estimations ◽  
Ideal Bose Gas

The paper presents a study of a non-standard model of fractional statistics. The exponential of the Gibbs factor in the expression for the occupation numbers of ideal bosons is substituted with the Tsallis q-exponential and the parameter q = 1 − α is considered complex. Such an approach predicts quantum critical phenomena, which might be associated with PT -symmetry breaking. Thermodynamic functions are calculated for this system. Analysis is made both numerically and analytically. Singularities in the temperature dependence of fugacity and specific heat are revealed. The critical temperature is defined by non-analyticities in the expressions for the occupation numbers. Due to essentially transcendental nature of the respective equations, only numerical estimations are reported for several values of parameters. In the limit of α → 0 some simplifications are obtained in equations defining the temperature dependence of fugacity and relations defining the critical temperature. Applications of the proposed model are expected in physical problems with energy dissipation and inderdisciplinarily in effective description of complex systems to describe phenomena with non-monotonic dependencies.

A Lumped Parameter Electromechanical Model for Describing the Nonlinear Behavior of Piezoelectric Actuators

1997 ◽  
Vol 119 (3) ◽  
pp. 478-485 ◽  
Author(s):  
M. Goldfarb ◽  
N. Celanovic
Keyword(s):  
System Analysis ◽  
Nonlinear Behavior ◽  
Piezoelectric Actuators ◽  
Bond Graph ◽  
Lumped Parameter Model ◽  
Input Output ◽  
Mechanical Stiffness ◽  
Analysis And Design ◽  
Lumped Parameter ◽  
Proposed Model

A lumped-parameter model of a piezoelectric stack actuator has been developed to describe actuator behavior for purposes of control system analysis and design, and in particular for control applications requiring accurate position tracking performance. In addition to describing the input-output dynamic behavior, the proposed model explains aspects of nonintuitive behavioral phenomena evinced by piezoelectric actuators, such as the input-output rate-independent hysteresis and the change in mechanical stiffness that results from altering electrical load. Bond graph terminology is incorporated to facilitate the energy-based formulation of the actuator model. The authors propose a new bond graph element, the generalized Maxwell resistive capacitor, as a lumped-parameter causal representation of rate-independent hysteresis. Model formulation is validated by comparing results of numerical simulations to experimental data.

ON CONDENSATION IN NON-IDEAL BOSE GAS

1989 ◽  
Vol 03 (06) ◽  
pp. 471-478
Author(s):  
D.P. SANKOVICH
Keyword(s):  
Critical Temperature ◽  
Low Temperature ◽  
Upper Bound ◽  
Bose Gas ◽  
The One ◽  
Ideal Bose Gas

A model of the non-ideal Bose gas is considered. We prove the existence of condensate in the model at sufficiently low temperature. The method of majorizing estimates for the Duhamel Two Point Functions is used. The equation for the critical temperature and the upper bound for the one-particle excitations energy are obtained.

scholarly journals Model of the Process of Conducting Computer Attacks Using Special Information Influences

2021 ◽  
pp. 12-20
Author(s):  
Sergey Kondakov ◽  
◽  
Ilya Rud ◽  
Keyword(s):  
Information Systems ◽  
Comparative Analysis ◽  
Complex Systems ◽  
Research Method ◽  
System Analysis ◽  
Level Of Abstraction ◽  
Proposed Model ◽  
Analysis And Synthesis ◽  
Computer Attacks ◽  
Special Information

Purpose of work: development of a model of the process of conducting a computer attack. Research method: theory of complex systems, comparative analysis within the framework of system analysis and synthesis. Result: it is shown that the application of the proposed model of the process of conducting computer attacks allows you to fully describe the process, taking into account its inherent features and characteristics. The use in the model of information from the MITRE ATTACK database of Mitre, which contains a description of the tactics, techniques and methods used by cybercriminals, allows you to reduce the level of abstraction and describe specific scenarios for conducting complex targeted computer attacks with the maximum approximation to practice. The developed model is supposed to be used to form scenarios of computer attacks when assessing the security of information systems.

Raman Scattering Studies on Superconducting YBa2Cu3O7−x, Semiconducting YBa2Cu3O6+x, and Possible Impurity Phases

1987 ◽  
Vol 99 ◽  
Author(s):  
A. Mascarenhas ◽  
H. Katayama-Yoshlda ◽  
S. Geller ◽  
J. I. Pánkové ◽  
S. K. Debt
Keyword(s):  
Critical Temperature ◽  
Raman Scattering ◽  
Temperature Dependence ◽  
Phonon Mode ◽  
Group Analysis ◽  
Factor Group ◽  
Anomalous Temperature Dependence ◽  
Anomalous Temperature ◽  
Mode Softening ◽  
Characteristic Lines

ABSTRACTA Raman spectroscopie investigation of specimens of superconducting YBa2Cu3O7−x and semiconducting YBa2Cu3O6+x indicates that in the range 100 to 700 cm-1, the characteristic lines of the superconductor at 13 K, are at 150, 338, 441, 507, 590, and 644 cm-1. Comparison of the Ranan spectra of the superconductor and the semiconductor indicates a mode stiffening of the pair at 338 and 441 cm-1, hut a mode softening of the pair at 507 and 590 cm-1. A factor group analysis leads to a tentative assignment of the Raman and infrared allowed modes. At temperatures 12K < T < 180K the Raman spectra of the superconductor indicate that the phonon mode at 338 cm-1 has an anomalous temperature dependence below the superconducting critical temperature (Tc).

Transfer of the unsaturated helium II film

1961 ◽  
Vol 260 (1300) ◽  
pp. 1-12 ◽  
Keyword(s):  
Heat Conduction ◽  
Critical Temperature ◽  
Temperature Dependence ◽  
Flow Rate ◽  
Vapour Pressure ◽  
Transfer Rate ◽  
Film Flow ◽  
Saturation Pressure ◽  
Considerable Reduction ◽  
Helium Ii

The critical transfer rate of the unsaturated helium II film has been measured on surfaces of glass and german silver by a heat conduction method. It is found that a considerable reduction of the transfer rate occurs when the vapour pressure over the film is decreased only slightly below the saturation value. At a given percentage of the saturation pressure, there exists a critical temperature above which film flow will not take place. This critical temperature is shown to be sharply defined, and to decrease with decreasing percentage satura­tion. At the full saturation pressure the transfer rate is markedly different on the various surfaces used, but as the vapour pressure over the film decreases the flow rate tends to become the same for all surfaces. The critical temperature for onset of superfluidity is also independent of the substrate. The temperature dependence of the transfer rate is different from that for the saturated film, but very similar to the variation found in the flow of liquid through channels of width less than that of the saturated film.

HREM and Image Simulation of Short-Range-Order Domains in Ion Irradiated Zirconolite

2000 ◽  
Vol 6 (S2) ◽  
pp. 392-393
Author(s):  
S. X. Wang ◽  
L. M. Wang ◽  
R. C. Ewing
Keyword(s):  
High Temperature ◽  
Critical Temperature ◽  
Temperature Dependence ◽  
Short Range ◽  
Radiation Effects ◽  
Short Range Order ◽  
Fluorite Structure ◽  
Range Order ◽  
Image Simulation ◽  
Ion Species

Zirconolite (CaZrTi2O7) is an important phase proposed for immobilization of plutonium. Radiation effects in zirconolite were studied by 1 MeV Kr+ and 1.5 MeV Xe+ irradiation at various temperatures. Zirconolite became amorphous at temperatures below a critical temperature, Tc. The critical temperature was found to be a function of ion species: Tc - 654 K for 1 MeV Kr+ and 710 K for 1.5 MeV Xe+. The temperature dependence of amorphization dose is shown in FIG. 1. Above Tc, the specimen remained crystalline after prolonged irradiation (up to 3.6×l015 ions/cm2). However, the high-temperature irradiated zirconolite was transformed into the fluorite structure (as shown by the strong diffraction maxima in FIG. 2). In addition to the maxima from the fluorite structure, strong diffuse maxima were observed surrounding the Bragg position of pyrochlore superlattice (FIG. 2).

Alteration of the stacked 2π/3 magnetic structure in the triangular lattice anti-ferromagnet LiCrS2

2001 ◽  
Vol 79 (11-12) ◽  
pp. 1427-1432
Author(s):  
A Lafond ◽  
W Henggeler ◽  
H Mutka ◽  
B Ouladdiaf
Keyword(s):  
Transition Temperature ◽  
Critical Temperature ◽  
Solid State ◽  
Elastic Scattering ◽  
Temperature Dependence ◽  
Triangular Lattice ◽  
Magnetic Ordering ◽  
Magnetic Scattering ◽  
Powder Samples ◽  
Anisotropic Interactions

LiCrS2 has magnetic Cr ions with spin S = 3/2 on a triangular lattice. Other researchers (J. Solid State Chem. 3, 590, 1971) concluded that this compound has an anti-ferromagnetic order with a stacked 2π/3 structure below a transition temperature of the order of TN = 50 K. We have re-examined this system with neutron scattering methods on powder samples, paying attention to the temperature dependence of the magnetic scattering. The overall characteristics of the magnetic ordering are in agreement with the earlier study but we have observed significant modifications of the stacked 2π/3 structure well below the critical temperature. The main new features observed on cooling from T = 25 K down to T = 1.5 K are (i) the gradual decrease from 2.5 µB to 2.3 µB of the ordered moment attributed to the 2π/3 structure, (ii) the appearance of new correlations corresponding to a multiplication of the magnetic unit cell, and (iii) the growth of a diffuse elastic scattering component that can be ascribed to a frozen disorder. These observation are not explained in the framework of the standard theoretical treatments concerning the stacked triangular anti-ferromagnet with Heisenberg or slightly anisotropic interactions. PACS Nos.: 75.10Nr, 75.25+z, 75.40Gb

Temperature dependence of turn-on time delay of semiconductor laser diode: Theoretical analysis

2010 ◽  
Vol 18 (4) ◽  
Author(s):  
M.S. Ab Rahman ◽  
M.R. Hassan
Keyword(s):  
Time Delay ◽  
Temperature Dependence ◽  
Semiconductor Laser ◽  
Laser Diode ◽  
Communication Systems ◽  
Recombination Coefficient ◽  
Turn On ◽  
Proposed Model ◽  
Wide Range ◽  
Dc Bias

AbstractTemperature dependence of the turn-on time delay (ton) of uncooled semiconductor laser diodes biased below and above threshold is analyzed in presence of data pattern effect. We show that even when the laser is biased at or slightly above threshold, the increase in temperature of operation will lead to increase in the threshold carrier (Nth) and consequently the laser diode will be biased below the threshold again and a significant value of ton will be produced. Thus, knowledge about a value of dc-bias current required to achieve zero ton within wide range of temperature degrees is important when considering uncooled laser diode in high-speed optical communication systems. The temperature dependence of ton is calculated according to the temperature dependence of Nth and Auger recombination coefficient (C) and not by the well-know exponentional relationship of threshold current with temperature. The temperature dependence of Nth is calculated according to the temperature dependence of laser cavity parameters. Advanced analytical model is derived in term of carrier density, recombination coefficients and the injection current (Iinj). The validity of proposed model is confirmed by a numerical method. In addition, approximated models are included where under specified assumptions the proposed model reduces to the well-known approximate models of ton. According to our typical values and at a specified value of modulation current, the dc-bias one (Iib) should be increased from Iib = Ith to Iib ≈ 1.25 and 1.5Ith in order to achieve approximately zero ton when the temperature increases from 25°C to 55°C and 85°C, respectively.

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