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1.
We discuss the notion of spin squeezing considering two mutually exclusive classes of spin-s states, namely, oriented and non-oriented states. Our analysis shows that the oriented states are not squeezed while non-oriented
states exhibit squeezing. We also present a new scheme for construction of spin-s states using 2s spinors oriented along different axes. Taking the case of s=1, we show that the ‘non-oriented’ nature and hence squeezing arise from the intrinsic quantum correlations that exist among
the spinors in the coupled state. 相似文献
2.
A. V. Rybina K. S. Nemkovski V. B. Filippov A. V. Dukhnenko 《Physics of the Solid State》2010,52(5):894-898
The first results of measuring dispersion curves of acoustic phonons in the ZrB12 superconductor are reported. The measurements have been conducted by the inelastic neutron scattering method on an ATOS three-axis
spectrometer (IR-8, Russian Research Centre “Kurchatov Institute,” Moscow) at room temperature with a single crystal grown
using a 99.5%-enriched 11B isotope. The results obtained have been analyzed in terms of the lattice dynamics model proposed earlier for rare-earth
dodecaborides. In this model, the constants of the force interaction of Zr atoms with one another and with the boron framework
have been determined. 相似文献
3.
A. V. Rybina P. A. Alekseev K. S. Nemkovski E. V. Nefeodova J. -M. Mignot Yu. B. Paderno N. Yu. Shitsevalova R. I. Bewley 《Crystallography Reports》2007,52(5):770-773
The density of phonon states for the YbB12 Kondo insulator is calculated from the inelastic neutron scattering spectra of this compound. It is established that thermal vibrations of rare-earth atoms predominantly occur in the low-energy range. These atoms are most weakly bound in the crystal structure of the YbB12 Kondo insulator. The high-energy part of the vibrational spectrum is determined by thermal vibrations of the boron atoms forming a rigidly connected structure of the compound. It is revealed that the temperature dependence of the intensity of the phonon peak attributed to thermal vibrations of the ytterbium atoms exhibits an anomalous behavior. This circumstance suggests that the magnetoelastic coupling occurring in the structure of the YbB12 Kondo insulator is relatively strong and can contribute to the magnetic excitation spectrum of this compound. 相似文献
4.
Alekseev PA Mignot JM Nemkovski KS Rybina AV Lazukov VN Ivanov AS Iga F Takabatake T 《J Phys Condens Matter》2012,24(20):205601
Peculiarities in the lattice dynamics of the Kondo insulator Y bB(12) have been studied by inelastic neutron scattering. Selected phonon modes were traced above and below the temperature region (T ~ 50 K) where the gap opens in the electron density of states. The intensities of some low-energy modes exhibit an anomalous temperature dependence for q vectors close to the Brillouin zone boundary, suggesting a renormalization of the phonon eigenvectors. This effect is thought to arise from a coupling with magnetic excitations of the same symmetry, which exist at nearby energies. It is argued that this magnetovibrational coupling may in turn play a role in the steep temperature crossover existing in Y bB(12) between the low-temperature (Kondo insulator) and high-temperature (incoherent spin-fluctuation) regimes, which is rapidly suppressed by lighter Zr substitution. 相似文献
5.
The aim of this brief report is to study the behaviour of sheath structure in a multi-component plasma with dust-neutral collisions.
The plasma consists of electrons, ions, micron size negatively charged dust particles and neutrals. The sheath-edge potential
and sheath width are calculated for collisionally dominated sheath. Comparison of collisionless and collisionally dominated
sheath are made. 相似文献
6.
E.V. Nefeodova P.A. Alekseev K.S. Nemkovski I.P. Sadikov N.Yu. Shitsevalova 《Journal of solid state chemistry》2006,179(9):2858-2861
To clarify the role of Yb-Yb correlations in the formation of the gap-like excitation spectrum of YbB12, the spin dynamics of strongly diluted Yb0.25Lu0.75B12 have been studied by inelastic neutron scattering in a wide temperature range. The data indicate that the spin gap is not suppressed by the dilution process even for large concentrations of Lu. However, the breaking-down of the Yb-sublattice periodicity leads to a strong smearing of the low-energy features and to a moderate suppression of the high-energy peak in the magnetic spectral response of YbB12. The interrelation of the spin and charge gaps is discussed. 相似文献
7.
Analysis of a TE011 mode composite sapphire-rutile dielectric resonator has been carried out to study the temperature variation of resonance
frequency, close to the Cs atomic clock hyperfine frequency of 9.192 GHz. The complementary behavior of dielectric permittivity
with temperature of the composite has been exploited to obtain the desired turning point in the resonant frequency. The frequency
of the composite structure is found to be independent of the shield diameter beyond four times the puck diameter. 相似文献
8.
P. A. Alekseev V. N. Lazukov K. S. Nemkovski J. -M. Mignot E. A. Goremychkin N. Yu. Shitsevalova A. V. Dukhnenko 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(8):1149-1152
Neutron spectroscopy results are presented for electron-doped YbB12-based systems. Electrondoping effects were obtained through the partial substitution of Yb for four-valence Zr, and through
the introduction of a small amount of carbon in the boron sublattice of a YbB12 condo insulator. The different character of the original YbB12 gap-type magnetic-excitation-spectrum changes was observed. 相似文献
9.
P. P. Parshin A. I. Chumakov P. A. Alekseev K. S. Nemkovski L. Dubrovinskii A. Kantor J. Perßon R. Rüffer 《Journal of Experimental and Theoretical Physics》2016,123(6):1073-1083
We analyze in detail the results of experimental investigations of the evolution of the thermal vibration spectra for iron atoms in iron monosilicide FeSi depending on two external parameters, viz., temperature T (in the range 46–297 K at pressure P = 0.1 MPa) and pressure P (in the range 0.1 MPa–43 GPa at temperature T = 297 K), obtained by nuclear inelastic scattering of synchrotron radiation. The decrease of the atomic volume is accompanied by a rearrangement of the phonon spectrum, which is manifested, in particular, in the splitting of the low-energy peak in the spectrum and in an increase of the energy for all phonons. The changes of the average energy of the iron atom vibrational spectrum and of the Debye energy with decreasing atomic volume are analyzed. Different versions of FeSi electron spectrum variation, which can be used to explain the observed phonon anomalies, are considered. 相似文献
10.
Nemkovski K. S. Alekseev P. A. Rybina A. V. Mignot J. -M. Flachbart K. Samuely P. Shitsevalova N. Yu. Paderno Yu. B. Iga F. Takabatake T. Lazukov V. N. Nefeodova E. V. Sadikov I. P. Tiden N. N. Bewley R. I. 《Crystallography Reports》2006,51(1):S139-S143
The phonon dispersion in RB12 (R = Yb, Lu) systems is studied in detail using inelastic neutron scattering over a wide range of energies (up to 55 meV). It is demonstrated that the main features of the lattice dynamics in the RB12 crystals can be described in terms of a simple model of force constants with a strong hierarchy of interatomic interactions in the systems: B-B ≫ B-R ≫ R-R. An interesting feature of the low-energy portion of the phonon spectrum is the weakly dispersive optical mode. According to the model calculations, this mode is associated with the relative displacements and “breathing” vibrations of the boron nanoclusters B12.
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