Even-parity spin-triplet paired states by combined effect of Hund’s rule and correlations in two-band Hubbard model: a brief overview

Universal aspects of the Hund’s rule induced spin-triplet pairing are analysed within the two-band Hubbard model on a square lattice. According to our calculations, this pairing mechanism in conjunction with the correlation effect can result in stability of the paired phase in the so-called purely repulsive interactions regime, in which there is no effectively attractive interaction. Furthermore, even though all of the interaction terms are of intrasite character, the pairing contains both intra- and inter-site components. In effect, the gap parameter has a mixture of s-wave and extended s-wave symmetries. The calculations have been carried out with the use of the Statistically Consistent Gutzwiller Approximation developed by us in recent years.     

Stark–Zeeman and Blokhintsev Spectra of Rydberg Atoms

Journal of Experimental and Theoretical Physics - The problem of Rydberg atomic spectra in crossed electric F and magnetic B fields (combined Stark–Zeeman effects), as well as an oscillating...     

Hund’s Rule and Metallic Ferromagnetism

We study tight-binding models of itinerant electrons in two different bands, with effective on-site interactions expressing Coulomb repulsion and Hunds rule. We prove that, for sufficiently large on-site exchange anisotropy, all ground states show metallic ferromagnetism: They exhibit a macroscopic magnetization, a macroscopic fraction of the electrons is spatially delocalized, and there is no energy gap for kinetic excitations.     

Radiative lifetimes of Rydberg states of BeⅠ and BeⅢ

By using the multichannel quantum defect theory(MQDT),we have evaluated the energy levels and lifetimes of 2sns ^3 S1,2snd ^3D(n=3-25)of BeI and 1 sns ^3s1,1snd ^3D(n=3-25)of BeⅢ,These energies and lifetimes that we have calculated not only agree with the recent measurements and theoretical calculation of Ref.4 and Ref.3, but also predict the lifetimes of 66 other highly excited states.     

Correlation properties of entangled multiphoton states and Bernstein’s paradox

A normally ordered characteristic function (NOCF) of Bose operators is calculated for a number of discrete-variable entangled states (Greenberger-Horne-Zeilinger (GHZ) and Werner (W) qubit states and a cluster state). It is shown that such NOCFs contain visual information on two types of correlations: pseudoclassical and quantum correlations. The latter manifest themselves in the interference terms of the NOCFs and lead to quantum paradoxes, whereas the pseudoclassical correlations of photons and their cumulants satisfy the relations for classical random variables. Three- and four-qubit states are analyzed in detail. An implementation of an analog of Bernstein’s paradox on discrete quantum variables is discussed. A measure of quantumness of an entangled state is introduced that is not related to the entropy approach. It is established that the maximum of the degree of quantumness substantiates the numerical values of the coefficients in multiqubit vector states derived from intuitive considerations.     

Structure and stability of various states of the EuC and EuC2 molecules

B3LYP level density functional theory （DFT） and multiconfiguration self-consistent-field （MCSCF） level ab initio method calculations have been performed on the basis of relativistic effective core potentials to investigate the nature of EuC and EuC2 molecules. The computed results indicate that the ground states of EuC and EuC2 are ^12∑^＋ and SA2, respectively. Dissociation potential energy curves of the low-lying electronic states of EuC have been calculated using the MCSCF method, and the same level calculation on EuC2 indicates that the dissociation energy of EuC2 of ground state compares well with the available experimental data. The bond characteristic is also discussed using Mulliken populations.     

Existence of Hartree–Fock excited states for atoms and molecules

For neutral and positively charged atoms and molecules, we prove the existence of infinitely many Hartree–Fock critical points below the first energy threshold (that is, the lowest energy of the same system with one electron removed). This is the equivalent, in Hartree–Fock theory, of the famous Zhislin–Sigalov theorem which states the existence of infinitely many eigenvalues below the bottom of the essential spectrum of the N-particle linear Schrödinger operator. Our result improves a theorem of Lions in 1987 who already constructed infinitely many Hartree–Fock critical points, but with much higher energy. Our main contribution is the proof that the Hartree–Fock functional satisfies the Palais–Smale property below the first energy threshold. We then use minimax methods in the N-particle space, instead of working in the one-particle space.     

The theoretical and experimental investigations of Stark structure in sodium Rydberg states atoms

The experimental results of the Stark structure of Na in the vicinity of n~*=21-23 with the external electric field from 0 to 380V/cm are reported. The theoretical calculation of the stark levels of Na based on the atomic potential model are in good agreement with experiment. The limiting error between the theory and experiment turns out to be due to experimental uncertainty.     

Analytic MRCI gradient for excited states: formalism and application to the n-π∗ valence- and n-(3s,3p) Rydberg states of formaldehyde

The previously developed formalism for the calculation of the analytic multireference (MR) CI energy gradient with respect to nuclear coordinates based on a single-state MCSCF calculation was extended to the case of state-averaged MCSCF. This extension is of particular importance for calculations of electronically excited states and enables automatic high-level geometry optimizations and saddle point searches on excited-state energy surfaces. Beyond MR-CI, the present analytic gradient method is also available for the MR-ACPF/AQCC methods including size-extensivity corrections for the multireference case. Full geometry optimizations for six electronic states of formaldehyde (valence and Rydberg states) are reported.     

Simultaneous classification of Oranges and Apples Using Grover’s and Ventura’ Algorithms in a Two-qubits System

In the present paper, simultaneous classification of Orange and Apple has been carried out using both Grover’s iterative algorithm (Grover 1996) and Ventura’s model (Ventura and Martinez, Inf. Sci. 124, 273–296, 2000) taking different superposition of two- pattern start state containing Orange and Apple both, one- pattern start state containing Apple as search state and another one- pattern start state containing Orange as search state. It has been shown that the exclusion superposition is the most suitable two- pattern search state for simultaneous classification of pattern associated with Apples and Oranges and the superposition of phase-invariance are the best choice as the respective search state based on one –pattern start-states in both Grover’s and Ventura’s methods of classifications of patterns.     

Violation of Bell’s inequality for continuous-variable EPR states

We construct a wide class of bounded continuous variables observables that lead to violations of Bell inequalities for the EPR state and give an intuitive Wigner function explanation how to predetermine which operators wont ever exceed the bounds given by local theories. We show that as examples of such operators, we can use continuous-variable observables that satisfy the commutation relations for the Pauli matrices.     

Theoretical study on 2s2p^6np Rydberg states of Cu^19＋ ion

We report on the calculations of transition wavelengths and weighted oscillator strengths for 2s 2 2p 6-2s2p 6 np （4≤n≤20） electric dipole （E1） transitions of Cu 19+ ion.The flexible atomic code （FAC） has been adopted for the calculations.Comparisons are made with the experimental data available,showing that the present results for 4 ≤n≤6 are more accurate than the previous calculated values.Furthermore,combining the quantum defect theory （QDT） with the transition energies of 2s22p～6-2s2p～6np,the quantum defects for 2s2p 6 np Rydberg series of Cu～（19+）ion are determined.In addition,the energies of any highly excited states （n>20） for this series can be reliably predicted using the QDT and the given quantum defects.The ionization energies for Cu¹⁹⁺ and Cu²⁰⁺ ions are also calculated and they excellently accord with previous experimental and calculated values.     

Hund’s coupling and the metal-insulator transition in the two-band Hubbard model

The Mott-Hubbard metal-insulator transition is investigated in a two-band Hubbard model within dynamical mean-field theory. To this end, we use a suitable extension of Wilsons numerical renormalization group for the solution of the effective two-band single-impurity Anderson model. This method is non-perturbative and, in particular, allows to take into account the full exchange part of the Hunds rule coupling between the two orbitals. We discuss in detail the influence of the various Coulomb interactions on thermodynamic and dynamic properties, for both the impurity and the lattice model. The exchange part of the Hunds rule coupling turns out to play an important role for the physics of the two-band Hubbard model and for the nature of the Mott-transition.     

Water in the Moon’s polar areas: Results of LEND neutron telescope mapping

The results of LEND neutron telescope mapping of the lunar surface are presented. The estimations obtained show that the water content in the regolith in the polar areas of the Moon reaches 0.4 % by weight and not directly determined by the illuminated surface.     

The effect of rubber dampers on engine’s NVH and thermal performance

Fins as extended surfaces are attached to the internal combustion engine surfaces for enhancing the heat transfer. However, these fins vibrate at various frequencies, which produce undesirable radiated noise. To mitigate this effect, automobile industry inserts rubber dampers between these fins. These rubber dampers reduce the fins’ amplitude of vibration and thus reduce the radiated noise from the fin surfaces. Investigations on the effect of rubber dampers on the engine’s NVH (Noise–Vibration–Harshness) and thermal performance using numerical (FEM and CFD) and experimental measurement have been presented in this paper. Experiments were conducted in the semi-anechoic chamber on an engine with and without rubber dampers to measure the radiated noise from the fins. It was found that rubber dampers assist in reducing engine high frequency noise signals at higher engine speeds. Modal and harmonic response analysis was carried out on various designs for NVH characteristics improvement. Prototypes of the final design was made and tested for the NVH performance. Computational fluid dynamics (CFD) simulations were performed on engine with and without rubber dampers to investigate the thermal performance. It was found that rubber dampers increase engine temperature by about 10%. Effect of rubbers dampers on the cost and environmental impact has also been discussed. This paper provides a systematic procedure to investigate the effect of rubber dampers and a method to eliminate these dampers from the engines with the same NVH and better thermal performances.     

Kinematics of Cherenkov’s effect with noninvariant velocity of light

The kinematics of Cherenkov’s effect is considered for an electron moving in the Minkowski space with universal time and velocity of light c = c ₀ (1 + v ²/c ₀²)^1/2, where c ₀ = 3⋅10 m/s is the invariant constant and v is the particle velocity. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 47–50, January, 2009.     

An investigation of the interaction between close-lying 2σ and 2II states of diatomic molecules

A perturbation calculation of the interaction between close-lying ²σ and ²II states of diatomic molecules has been carried out to the fourth order. The formula for the spin-splitting of the ²σ states thus obtained has been found to yield a proper explanation for the large anomalies encountered in the spinsplitting of the B ²σ states of the hydrides and deuterides of Ca, Sr and Ba. Especially for CaH, CaD, SrH and SrD good agreement between theoretical and fitted values has been found for the higher-order correction terms to the spin-splitting.     

Elastic Properties of Graphene-Like Compounds: the Keating’s and Harisson’s Models

Physics of the Solid State - The third-order elastic constants, the pressure dependences of the second-order elastic constants, the Kleinman and Grüneisen parameters, and the thermal expansion...