Spin-resolved correlations in the warm-dense homogeneous electron gas

We have studied spin-resolved correlations in the warm-dense homogeneous electron gas by determining the linear density and spin-density response functions, within the dynamical self-consistent mean-field theory of Singwi et al. The calculated spin-resolved pair-correlation function g _{σ σ′}(r) is compared with the recent restricted path-integral Monte Carlo (RPIMC) simulations due to Brown et al. [Phys. Rev. Lett. 110, 146405 (2013)], while interaction energy E _int and exchange-correlation free energy F _xc with the RPIMC and very recent ab initio quantum Monte Carlo (QMC) simulations by Dornheim et al. [Phys. Rev. Lett. 117, 156403 (2016)]. g _↑↓(r) is found to be in good agreement with the RPIMC data, while a mismatch is seen in g _↑↑(r) at small r where it becomes somewhat negative. As an interesting result, it is deduced that a non-monotonic T-dependence of g(0) is driven primarily by g _↑↓(0). Our results of E _int and F _xc exhibit an excellent agreement with the QMC study due to Dornheim et al., which deals with the finite-size correction quite accurately. We observe, however, a visible deviation of E _int from the RPIMC data for high densities (~8% at r _s = 1). Further, we have extended our study to the fully spin-polarized phase. Again, with the exception of high density region, we find a good agreement of E _int with the RPIMC data. This points to the need of settling the problem of finite-size correction in the spin-polarized phase also. Interestingly, we also find that the thermal effects tend to oppose spatial localization as well as spin polarization of electrons.     

Scattering of Josephson plasmons on random quantum jumpers in a disordered <Emphasis Type="Italic">I</Emphasis>-layer of an <Emphasis Type="Italic">S</Emphasis>–<Emphasis Type="Italic">I</Emphasis>–<Emphasis Type="Italic">S</Emphasis> junction

A formula for the relaxation time of Josephson plasmons on random quantum jumpers, i.e., quantum resonant-percolation trajectories (QRPT) in a disordered I-layer of a tunnel S–I–S junction is derived. Domain Ω_r (μ ? E₀, c), in which the strongest plasmon damping takes place, is plotted in the plane of parameters (μ ? E₀, c).     

Meson Effect in the Proto Neutron Star PSR J0348+0432

The effect of mesons f ₀(975) (named as f), ?(1020) (named as ?) and δ on the moment of inertia of the PNS PSR J0348+0432 is examined in the framework of the relativistic mean field theory considering the baryon octet. It is found that the energy density ε and pressure p will increase considering the mesons δ whereas will decrease as the mesons f and ? being considered. When the mesons f,? and δ are considered, the energy density and pressure will all decrease. It is also found that the contribution of mesons f, ? and δ to the central energy density is only the central energy density’s 0.06 ～0.6% whereas the contribution of mesons f, ? and δ to the central pressure is the central pressure’s 4 ～7%. For the radius, it will decrease when the contributions of mesons f, ? and δ are considered. The moment of inertia I will increase considering the mesons δ whereas will decrease as the mesons f and ? being considered. When the mesons f, ? and δ are all considered, the moment of inertia will decrease. It is found that the contribution of mesons f and ? to moment of inertia is 4 ～9 times larger than that of mesons δ. Our results show that the mesons f, ? and δ contribute to the moment of inertia’s 2 ～5%.     

Moments of inertia of neutron stars in relativistic mean field theory: The role of the isovector scalar channel

With the inclusion of the isovector scalar channel in the meson-nucleon couplings, taking DD-MEδ as an effective interaction, the moments of inertia of neutron stars possessing various stellar masses are studied within the density dependent relativistic mean field(RMF) theory. The isovector scalar channel contributes to the softening of the neutron-star matter equation of state(EOS)and therefore the reduction of the maximum mass and radius of neutron stars. Smaller values of the total moment of inertia I and the crustal moment of inertia ?I are then obtained in DD-MEδ via numerical procedure in comparison with those in other selected RMF functionals. In addition, the involvement of the isovector scalar channel lowers the thickness of the neutron star crust and its mass fraction as well. The sensitivity to both the crustal mass and stellar radius causes the crustal moment of inertia to be more obviously reduced than the total one, eventually leading to a suppression on the fraction of crustal moment of inertia?I/I in DD-MEδ. The results indicate the crustal moment of inertia as a more sensitive probe of the neutron-star matter EOS than the total one, and demonstrate that the isovector scalar meson-nucleon couplings in the RMF theory could exert influence over the physics of pulsar glitches.     

Auger- und Coster-Kronig-Übergänge der M-Schale von Krypton

The Auger spectra of theM ₂,M ₃,M ₄,M ₅ subshells of krypton and the Coster-Kronig spectra of theM ₁,M ₂,M ₃ subshells of krypton were measured with an electrostatical spectrometer. The ionization in theM shells was caused by electron impact. The use of a gaseous target made it possible to measure the Auger lines even at energies as low as 25 eV. The absolute energies and relative intensities of a great number of transitions were determined: 22 of theM _{4, 5} spectrum, 14 of theM _{2, 3} spectrum and 2 of theM ₁ spectrum. Only in the case of theM _{2, 3} spectrum a comparison between the relative intensities, determined experimentally, and those calculated byRubenstein forZ=47 was possible. The agreement is only qualitatively. Moreover, from the Auger electron energies measured, the following binding energies were calculated:E(M ₁)=(292,1±1,0) eV,E(M ₂)=(222,1±0,6) eV,E(M ₃)=(214,6±0,6)eV,E(N ₁ N ₁)=(62,81±0,05) eV.     

Some exact solutions of the local induction equation for the motion of a vortex in a Bose–Einstein condensate with a Gaussian density profile

The dynamics of a vortex filament in a Bose–Einstein condensate whose equilibrium density in the reference frame rotating at the angular velocity Ω is Gaussian with the quadratic form r·D?r has been considered. It has been shown that the equation of motion of the filament in the local-induction approximation permits a class of exact solutions in the form R(β, t) = βM(t) + N(t) of a straight vortex, where β is the longitudinal parameter and is the time. The vortex slips over the surface of an ellipsoid, which follows from the conservation laws N · D?N=C ₁ and M · D?N=C ₀=0. The equation of the evolution of the tangential vector M(t) appears to be closed and has integrals of motion M ·D?M=C ₂ and (|M| ? M· G?Ω) = C, with the matrix G? = 2(I?TrD? ? D?)^?1. Crossing of the respective isosurfaces specifies trajectories in the phase space.     

Winkelkorrelationsmessungen an >30y Holmium 166 und Bestimmung desg R -Faktors des 4+-Rotationsniveaus von Erbium 166

The spins of several excited states of Er¹⁶⁶ have been investigated byγγ-angular correlation measurements. The spin sequence 0+, 2+, 4+, 6+ for the ground state rotational band was presumed to be correct. Unique assignments were derived for the states of 1076 keV, 1377 keV and 1785 keV asI=5, 7 and 6 respectively. These results are in agreement with the spins proposed byGallagher jr. andSoloviev. The multipolarities of theγ-transitions of 408 keV, 709 keV, 811 keV and 831 keV were derived as 95%E1+(5±1)%M2, 99·6%E1+(0·4±0·5)%M2, 99·1%E2+(0·9±0·3)%M1, and 96·1%E2+(3·9±1)%M1 respectively. The unusual mixing ratios of the transitions of 811 keV and 831 keV can be understood as a consequence of theK-selection rule. Eachγ-transition from the 1785 keV state should be stronglyK-forbidden and one expects a half-life ofT _1/2≈3·10^?9s. A measurement of the time spectrum of the coincidences between theβ-radiation and the high energyγ-lines gave however:T _1/2(1785 keV state)≦3·10^?10s. The rotation of the angular correlation between the 184 keV line and theγ-group at 820 keV has been measured in an external magnetic field of 53000 gauss as:ω·τ(4+)=0·083±0·006. This value contains small corrections for an additional rotation of the angular correlation of the 831 keV–184 keV triple cascade in the 6+state and for a small attenuation by internal fields. WithT _1/2(4+state)=1·23·10^?10s, andβ=7·08 one gets for theg-factorg _R=+0·266±0·024 in good agreement with recent results for the 2+ state.     

Mean-square displacements of metal and boron atoms in crystal lattices of rare-earth hexaborides

The intensities of the I₄₁₀ and I₄₁₁ reflections of nine rare-earth hexaborides MB₆ (M=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy) are experimentally studied in the temperature range 4.2–300 K. The mean-square displacements of metal and boron atoms are calculated from the temperature dependences of the intensities I₄₁₀(T) and I₄₁₁(T). The characteristic temperatures of the metal (θ_M) and boron (θ_B) sublattices of rare-earth hexaborides are determined in the Debye approximation. It is found that the characteristic temperatures decrease with an increase in the atomic number of the metal.     

Vergleich der Davydov-Theorie mit dem Modell des achsialsymmetrischen Kreisels mit Rotation-Vibrations-Wechselwirkung für deformiertegg-Kerne

For deformed even-mass nuclei the model of the axial-symmetric vibrating top with rotation-vibration-interaction is compared to the Davydov-model without and with aβ-band. TheE2-transition-probabilities are calculated. The coefficientsB _ze andC fromE=A I(I+1) ?B _ze I ²(I+1)²+C I ³(I+1)³ are obtained. For the transition-probabilities from the states of the γ-band to the states of the ground state band as well as forB andC the Davydov-model yields values only about half of those obtained from the RV-theory. A comparision to the present availuable experimental data is made. In the RV-model the agreement is better than in the Davydov-theory.     

Optical 4<Emphasis Type="Italic">f</Emphasis>-4<Emphasis Type="Italic">f</Emphasis> transitions in multiferroic HoMnO<Subscript>3</Subscript>

In the absorption spectra of the hexagonal single-crystal manganite HoMnO₃ in the paramagnetic ferroelectric state, lines near 1.1 and 2.0 μm were observed associated with the transitions ⁵ I ₈ → ⁵ I ₆ and ⁵ I ₈ → ⁵ I ₇, respectively, within the 4f ¹⁰ configuration of the Ho³⁺ ion. At T = 80 K, to the ⁵ I ₈ → ⁵ I ₇ transition corresponds one band at 1.9 μm for both polarizations E ∥ c and E ⊥ c. As the temperature increases from 80 to 293 K, a low-energy band with a peak at 2.04 μm for E ⊥ c and a peak at 2.07 μm for E ∥ c arises associated with transitions from an excited Stark level of the ground ⁵ I ₈ multiplet to the Stark levels of the ⁵ I ₇ multiplet and with an increase in the population of the initial Stark level, the energy of which is ～100 K.     

Problems of the quantum theory of measurement

After a short review of the present situation of the quantum theory of measurement, a formulation of the measuring process is given, which allows an “objective” interpretation. Starting from the unitary time transformation of the states of the measured systemS and the measuring deviceM, it is shown that after appropriate specification of the interaction HamiltonianH _int betweenS andM and the macroscopic structure ofM, the statistical operatorW ofS+M approximately develops into the mixture, which is desired as result of the measuring process. During the process the interference terms practically vanish in the sense of weak operator convergence, while on the other hand their Hilbert-Schmidt norm remains constant.     

Aufbau eines automatisch arbeitenden π√2-Spektrometers und Untersuchung des Konversionslinienspektrums von In114m und ThB mit Folgeprodukten

An automatically operatedπ√2 spectrometer is described. The regulated current supply is transistorized. With this spectrometer the electron spectra of In^114m and of ThB with daughter products have been investigated. TheK/L ratio of the 191 keV isomeric transition in In^114m was found to be 1·25±0·03, in excellent agreement with the theoretical value ofSliv andBand. In the electron spectrum of ThB and daughter products 46 lines were found betweenB?=1750Г cm andB?=10000Г cm. Some of them are new. Most important is a new weak line atB?=7030Г cm which fixes a new level atE=1·807 MeV in ThC′ (Po²¹²). Simultaneously the earlier reported discrepancy between electron andγ-ray intensities for 1·8 MeV transition energy is resolved. There is anE0 transition of 1·800 MeV while the new line is theK conversion line of a new radiative transition (most probablyM2). A spin ofI=2+ is assigned to the 1·680 MeV level of ThC′. The 0·953 MeV transition from this level isM1, withE0 admixture.     

Dependence of the magnitude and direction of the persistent current on the magnetic flux in superconducting rings

The obtained periodic magnetic-field dependences I _c+(Φ/Φ₀) and I _c?(Φ/Φ₀) of the critical current measured in opposite directions on asymmetric superconducting aluminum rings has made it possible to explain previously observed quantum oscillations of dc voltage as a result of alternating current rectification. It was found that a higher rectification efficiency of both single rings and ring systems is caused by hysteresis of the current-voltage characteristics. The asymmetry of current-voltage characteristics providing the rectification effect is due to the relative shifts of the magnetic dependences I _c?(Φ/Φ₀) = I _c+(Φ/Φ₀ + Δ?) of the critical current measured in opposite directions. This shift means that the position of I _c+(Φ/Φ₀) and I _c?(Φ/Φ₀) minima does not correspond to n + 0.5 magnetic flux Φ quanta, which is in direct contradiction to measured Little-Parks resistance oscillations. Despite this contradiction, the amplitude I _{c, an}(Φ/Φ₀) = I _c+(Φ/Φ₀) ? I _c?(Φ/Φ₀) of critical current anisotropy oscillations and its variations with temperature correspond to the expected amplitude of persistent current oscillations and its variations with temperature.     

Electron paramagnetic resonance of Cr<Superscript>3+</Superscript>-Li<Superscript>+</Superscript> centers in (Cr,Li): Mg<Subscript>2</Subscript>SiO<Subscript>4</Subscript> synthetic forsterite

Synthetic single crystals of chromium-and lithium-doped forsterite, namely, (Cr,Li): Mg₂SiO₄, are studied using electron paramagnetic resonance spectroscopy. It is revealed that, apart from the known centers Cr³⁺(M1) and Cr³⁺(M2) (with local symmetries C_i and C_s, respectively), these crystals involve two new types of centers with C₁ symmetry, namely, Cr³⁺(M1)′ and Cr³⁺(M2)′ centers. The standard parameters D and E in a zero magnetic field [zero-field splitting (ZFS) parameters expressed in GHz] and principal components of the g tensor are determined as follows: D=31.35, E=8.28, and g=(1.9797, 1.9801, 1.9759) for Cr³⁺(M1)′ centers and D=15.171, E=2.283, and g=(1.9747, 1.9769, 1.9710) for Cr³⁺(M2)′ centers. It is found that the lowsymmetric effect of misalignment of the principal axes of the ZFS and g tensors most clearly manifests itself (i.e., its magnitude reaches 19°) in the case of Cr³⁺(M2)′ centers. The structural models Cr³⁺(M1)-Li⁺(M2) and Cr³⁺(M2)-Li⁺(M1) are proposed for the Cr³⁺(M1)′ and Cr³⁺(M2)′ centers, respectively. The concentrations of both centers are determined. It is demonstrated that, upon the formation of Cr³⁺-Li⁺ ion pairs, the M1 position for chromium appears to be two times more preferable than the M2 position. Reasoning from the results obtained, the R₁ line (the ²E → ⁴A₂ transition) observed in the luminescence spectra of (Cr,Li): Mg₂SiO₄ crystals in the vicinity of 699.6 nm is assigned to the Cr³⁺(M1)′ center.     

Novel features of the fragment mass variance in fission of hot nuclei

On the basis of data obtained by the incomplete fusion reactions ⁷Li(43A MeV)+²³²Th and ¹⁴N(34A MeV)+¹⁹⁷Au, the energy dependence of the variance (σ _M ² ) of the fragment mass in fission of highly heated nuclei has been investigated for total excitation energies E _tot ^* ranging from 50 up to 350 MeV. The dependence σ _M ² E _tot ^* shows some unexpected features when E _tot ^* exceeds a value of about 70 MeV. After this value, the steady increase of σ _M ² expected from its temperature dependence changes to some kind of plateau between 100 and 200 MeV. Further on, at E _tot ^* in excess of about 250 MeV, the variance is found to increase again sharply. In order to analyze this behavior quantitatively, a dynamical stochastic model has been developed. The model employs the one-body dissipation mechanism and describes the decay of highly excited and rotating nuclei by fission and light-particle evaporation. It satisfactorily explains the measured prior-to-scission neutron multiplicities and the experimental mass variances up to E _tot ^* ?250 MeV, but the stochastic treatment does not reveal any increase in σ _M ² at higher excitation energies in contradiction with the data.     

Komar energy and Smarr formula for noncommutative inspired Schwarzschild black hole

We calculate the Komar energy E for a noncommutative inspired Schwarzschild black hole. A deformation from the conventional identity E = 2ST _H is found in the next to leading order computation in the noncommutative parameter θ (i.e. \({\mathcal{O}(\sqrt{\theta}e^{-M^2/\theta})}\)) which is also consistent with the fact that the area law now breaks down. This deformation yields a nonvanishing Komar energy at the extremal point T _H  = 0 of these black holes. We then work out the Smarr formula, clearly elaborating the differences from the standard result M = 2ST _H , where the mass (M) of the black hole is identified with the asymptotic limit of the Komar energy. Similar conclusions are also shown to hold for a deSitter–Schwarzschild geometry.     

Zur Theorie der Vorwärtsasymmetrie bei der Photospaltung des Deuterons

The forward asymmetry in the differential cross section for the photo disintegration of the deuteron has been calculated on the basis of a phenomenological theory for energies up to 80 MeV. The formulas for this asymmetry, which come from theE1-E2-andM1-M2-interference, are given, assuming the validity ofSiegert's theorem. TheE2-andM2-amplitudes are calculated approximately, using the Hulthén wavefunction with a 4% D-state admixture for the ground state and scattered waves determined by the phase shifts given by Marshak for the final states. The contribution of theM1-M2-interference turns out to be unimportant for the asymmetry, theE1-E2-interference giving the main effect. In the differential cross section,dσ/dΩ=a + b sin ² ? + c cos ? + d cos ? sin ² ?, we have obtained a very low value forc and the ratioc/d is approximately equal toa/3b. This is in contradiction to the assumptionc/d=a/b made in the previous analysis of the experimental data. This ratio seems to be insensitive to the value of the D-state admixture. For the lover energiesE _γ=10 MeV andE _γ=20 MeV the theoretical values for “d” are in agreement with the experimental ones. For the energies 54 and 80 MeV we have made a comparison of the theoretical differential cross sectiondσ/dΩ, taking into account the values for “a” and “b”, obtained in a former work ie, with the measureddσ/dΩ.     

TeV signatures of compact UHECR accelerators

We numerically study particle acceleration by the electric field induced near the horizon of a rotating supermassive (M ～ 10⁹–10¹⁰M_⊙) black hole embedded in the magnetic field B. We find that acceleration of protons to the energy E ～ 10²⁰ eV is possible only at extreme values of M and B. We also find that the acceleration is very inefficient and is accompanied by a broad-band MeV-TeV radiation whose total power exceeds the total power emitted in ultrahigh energy cosmic rays (UHECRs) at least by a factor of 1000. This implies that if O(10) nearby quasar remnants were sources of proton events with an energy E > 10²⁰ eV, then each quasar remnant would, e.g., overshine the Crab Nebula by more than two orders of magnitude in the TeV energy band. Recent TeV observations exclude this possibility. A model in which O(100) sources are situated at 100–1000 Mpc is not ruled out and can be experimentally tested by present TeV γ-ray telescopes. Such a model can explain the observed UHECR flux at moderate energies E ≈ (4–5) × 10¹⁹ eV.