On the role of Δ-resonance in the pion production in collisions of heavy intermediate-energy ions in the hydrodynamic approach

Pion production in heavy-ion collisions is considered within the hydrodynamic approach. It is shown that consideration of pion production as a result of Δ-resonance decay (Δ → N + π) leads to hardening of the high-energy “tails” of subthreshold pions.     

The Structure of the Algebra of Observables in the Intermediate Situation of the ∈-Model

We look at the action of the spin-1/2 operatorsof quantum mechanics on the state of an entity in aphysical way, and use this as a guideline to define theoperators of the intermediate situations of a general spin-1/2 measurement model called the-model. Then we test the possible linearity ofthe operators so constructed.     

Calculation of the fine structure of the level in Rydberg state of lithium

The level shift and level formula of lithium atom in Rydberg states are achieved by means of the calculation of polarization of the atomic core （including the contribution of dipole moment, quadrupole moment and octupole moment） ; meanwhile, the effect of relativity theory, the orbital angular momentum L and the spin angular momentum S coupling （IS coupling）, and high order correction of the effective potential are considered. Thesome fine structures （N = 5- 12, L = 4-9, J = L ± 1/2） and the corresponding level intervals in Rydberg statescan be calculated by the above-mentioned level formula and compared with correlated experimental data.     

Calculation of the fine structure of the level in Rydberg state of lithium

The level shift and level formula of lithium atom in Rydberg states are achieved by means of the calculation of polarization of the atomic core (including the contribution of dipole moment, quadrupole moment and octupole moment);meanwhile, the effect of relativity theory, the orbital angular momentum L and the spin angular momentum S coupling (LS coupling), and high order correction of the effective potential are considered. The some fine structures (N=5～12,L=4～9,J=L±1/2) and the corresponding level intervals in Rydberg states can be calculated by the above-mentioned level formula and compared with correlated experimental data.     

Ambiguities of the Seiberg-Witten Map in the Presence of Matter Field

The ambiguities of the Seiberg-Witten map for gauge field coupled with fermionic matter are discussed.We find that only part of the ambiguities can be absorbed by gauge transformation and/or field redefinition and thus are negligible.The existence of matter field makes some other part of the ambiguities difficult to be absorbed by gauge transformation of field regefinition.     

Use of ɛ expansions in the theory of the gravitational effect

The equations of state found by the expansion method by Brézin, Wallace, and Wilson and Avdeeva and Migdal are applied to the investigation of the gravitational effect in the critical region. As a result, expansions are obtained for the numerical coefficients in the asymptotic behaviors of the scale functions of these equations. The results of the calculation of the coefficients are compared with available experimental data for a number of liquids and magnets.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 77–81, May, 1980.     

Description of the evolution of the state of “josephson atoms” in the context of the informational interpretation of quantum mechanics

The evolution of a quantum system is informationally interpreted and used to describe decay in the coherent states of Josephson atoms, including qubits based on two- and three-junction superconducting quantum interferometers. The reduced Lindblad equation is employed to examine the measurement procedure of the Josephson qubit state and the influence of a measuring device on its coherent-state decay.     

Triangle Geometry of the Qubit State in the Probability Representation Expressed in Terms of the Triada of Malevich’s Squares

We map the density matrix of the qubit (spin-1/2) state associated with the Bloch sphere and given in the tomographic probability representation onto vertices of a triangle determining Triada of Malevich’s squares. The three triangle vertices are located on three sides of another equilateral triangle with the sides equal to\( \sqrt{2} \). We demonstrate that the triangle vertices are in one-to-one correspondence with the points inside the Bloch sphere and show that the uncertainty relation for the three probabilities of spin projections +1/2 onto three orthogonal directions has the bound determined by the triangle area introduced. This bound is related to the sum of three Malevich’s square areas where the squares have sides coinciding with the sides of the triangle. We express any evolution of the qubit state as the motion of the three vertices of the triangle introduced and interpret the gates of qubit states as the semigroup symmetry of the Triada of Malevich’s squares. In view of the dynamical semigroup of the qubit-state evolution, we constructed nonlinear representation of the group U(2).     

Anisotropy of the Resonance Transformation of the Microhardness of Crystals after Their Exposure in the EPR Scheme in the Earth’s Magnetic Field

It is shown that the preliminary exposure of ZnO, triglycine sulfate, and potassium hydrogen phthalate crystals in ultralow crossed magnetic fields—Earth’s magnetic field and ac pump field—leads to a resonance change in their microhardness. The resonance frequency of microhardness peaks is determined by the classical condition of electron paramagnetic resonance only at certain orientations of the crystals with respect to the Earth’s magnetic field B_Earth. Rotations of all samples with respect to the direction B_Earth by angle θ reduce the resonance frequency in proportion to cosθ. The observed anisotropy has been attributed to the presence of their own local magnetic fields B_loc ? B_Earth in the crystals.     

Measurement of sensitivity of transducer in the field of NDT by the reciprocity technique

The sensitivity of a transducer should be an important characteristic inthe field of NDT.But so far,no method for this measurement of the sensitivity of atransducer applied to the ultrasonic flaw detection is available.In this paper thetransducer is regarded as a plane source and the reciprocity parameter under thecondition of the far field is derived.We have calibrated the sensitivity of ultrasonictransducers with the reciprocity technique in the solid sample.The experimentsshow and confirm that the transmitting and receiving sensitivities of the transducerapplied to NDT can be exactly measured.The precision of the measurement is with-in ± 1dB under a certain coupling condition.     

Measurement of the Floor Tilt in Experimental Determination of the Gravitational Constant

A prototype of a device with an impact structure for measuring the floor tilt has been built in our laboratory. The mechanical construction and the capacitive transducer of the device are introduced. Experimental results indicate that the floor tilt is about 16#tad in our cavity laboratory, and the uncertainty AG/G caused by such tilt is less than 0.54 parts per million (ppm), so the floor tilt can be reasonably neglected in the experimental determination of the gravitational constant G with the total uncertainty of about l0ppm.     

Analysis of the Structure of the Bands in the IR Spectrum of β-D Glucose by the Regularized Method of Deconvolution

Deconvolution of the IR absorption spectrum of -D glucose in the spectral range 1500–450 cm^–1 has been carried out. The results of the deconvolution were compared with the IR and Raman spectra recorded at room and low temperatures and with the data obtained by theoretical calculations for the frequencies of the normal vibrations of the -D glucose molecule in the crystalline state. It is shown that deconvolution of the IR spectra recorded at room temperature makes it possible to separate the bands observed experimentally only at a very low temperature of the sample and a number of components that were not resolved earlier. The number of bands separated on deconvolution of the IR spectra of -D glucose in the spectral range 1500–450 cm^–1 is more than twice the number of visible absorption maxima in the usual spectrum. The results of deconvolution of the IR spectrum of -D glucose are in good agreement with the data of theoretical calculations for the frequencies of the normal vibrations of the -D glucose molecule in the crystalline state. The existence of the factor-group (Davydov) splitting of a number of frequencies of the nondegenerate fundamental vibrations of molecules in a crystal cell has been revealed in the IR spectrum of -D glucose. It was concluded that the model of an isolated molecule is insufficient for detailed theoretical interpretation of the vibrational spectra of carbohydrates.     

Calculation of the binding energy and of the parameters of low-energy scattering in the Λnp system

The cluster-reduction method is used to solve the differential Faddeev equations for S=1/2, T=0 and S=3/2, T=0 spin-isospin states of the Λnp system in the s-wave approximation. The NN interaction is simulated on the basis of the MT I–III potential model, and the ΛN potential is set to V _ΛN =V _NN /2. This simple option makes it possible to reproduce faithfully the binding energy of the hypertriton _Λ ³ H. The doublet and quadruplet Λd scattering lengths and the low-energy phase shifts are calculated. It is shown that the effective-range approximation is applicable to the cases of doublet and quadruplet scattering.     

Challenges in uncovering the origin of the proton's spin

One of the most fascinating challenges facing modern strong interaction physics is to understand the origin of the spin of the nucleon in terms of the spin and orbital angular momentum of the quarks and gluons.We review recent progress on this problem as well as some of the uncertainties associated with state of the art lattice QCD simulations.In particular,we explain the importance of the corrections associated with chiral extrapolation and finite volume corrections,especially for the term B（0） extracted from the appropriate low moment of the deeply virtual Compton scattering amplitude.     

On the effect of lead concentration on the kinetics of contact melting in the Sn–Pb–Bi system in the presence of electromigration

It is determined by electron microscopy that the contact layer in the Sn–(Bi + 30 wt % Pb) system contains separate solid inclusions, while the contact layer in the Sn–(Bi + 40 wt % Pb) system is microheterogeneous. The observed structural states of alloys in the contact layers are explained by a change in the concentration of the initial contacting samples. The effect of the alloy structure and electromigration on the kinetics of contact melting is found.     

Kinetics of the β→α transformation and the hierarchical nature of structure defects in the two-phase state in the Pd-H system

Possible types of time dependences p(t) describing the kinetics of the β→α a transformation in the Pd-H system are presented based on the theory of hierarchical structures. It is shown that one factor influencing the change in the time dependence p(t) is the degree of regularity in the distribution of defects in the hierarchical complexes and the strength of the hierarchical coupling determining the number of hierarchically coupled levels. Analysis of the relations obtained and the experimental data made it possible to distinguish the most likely physical causes for the retardation of the β→α a transformation. Fiz. Tverd. Tela (St. Petersburg) 49, 1621–1626 (September 1999)     

Significance of the Formal Quantum Number in the Highly Excited Vibration of the DCN Molecule

For the eigenstates of the highly excited vibration of the simple molecule DCN with two stretching modes,a classical approach in a multi-dimensional coset phase space is employed to show that the formal quantum numbers are related to regular or least “irregular” trajectories,with zero or least Lyapunov exponents,and are always located in the inner regions of the phase space.This property reflects that they are the approximate constants of motion.It is also demonstrated that formal quantum numbers correspond to the significant phase space dencity.     

Scaling of the shear viscosity of the system nitrobenzene—n-hexane in the critical region

The shear viscosity of the system nitrobenzene—n-hexane was measured along the isochores near the critical concentration. By applying the empirical formula η = η_idε^-Φ _sp, the critical exponent of the shear viscosity Φ was determined.     

Does the characteristic value of the discontinuity of the isotropic-mesophase transition in n-cyanobiphenyls exist?

Results of the extended Landau-de Gennes model analysis and experimental studies of the isotropic-nematic (I-N) and isotropic-smectic-A (I-SmA) phase transitions in rod-like liquid crystalline n-alkylcyanobiphenyls are presented. Experiments were carried out as a function of temperature and pressure using the static dielectric permittivity and its 'nonlinear' (strong electric field related) counterpart-the low-frequency nonlinear dielectric effect. Precise estimations of the values of the discontinuity of the isotropic-mesophase transitions (ΔT) for nCB from n?=?3-14 have been obtained. It is suggested that for each nCB a unique, characteristic minimal value of ΔT, associated with the I-N-SmA triple point, exists. For 'shorter' nCBs it can be hidden in the negative pressures domain. The possibility of the extension of the 'melting curve' into the negative pressures region as well as the appearance of the 'melting inversion' at high enough pressures is indicated.