Search results for "normal"
showing 10 items of 2571 documents
XXZ-like phase in the F-AF anisotropic Heisenberg chain
2008
By means of the Density Matrix Renormalization Group technique, we have studied the region where $XXZ$-like behavior is most likely to emerge within the phase diagram of the F-AF anisotropic extended ($J-J'$) Heisenberg chain. We have analyzed, in great detail, the equal-time two-spin correlation functions, both in- and out-of- plane, as functions of the distance (and momentum). Then, we have extracted, through an accurate fitting procedure, the exponents of the asymptotic power-law decay of the spatial correlations. We have used the exact solution of $XXZ$ model ($J'=0$) to benchmark our results, which clearly show the expected agreement. A critical value of $J'$ has been found where the r…
Magnetic properties of smooth terminating dipole bands in 110,112Te
2006
Three strongly coupled sequences have been established in Te-110,Te-112 up to high spins. They are interpreted in terms of deformed structures built on proton 1-particle-1-hole excitations that reach termination at I similar to 40h. This is the first observation of smooth terminating dipole structures in this mass region. Lifetime measurements have allowed the extraction of experimental B(M 1; 1 -> I - 1) and B(E2; I -> I - 2) reduced transition rates for one of the dipole bands in Te-110. The results support the deformed interpretation. (c) 2006 Elsevier B.V. All rights reserved.
Sum Frequency Generation Spectra from Velocity–Velocity Correlation Functions
2017
We developed an expression for the calculation of the sum frequency generation spectra (SFG) of water interfaces that is based on the projection of the atomic velocities on the local normal modes. Our approach permits one to obtain the SFG signal from suitable velocity-velocity correlation functions, reducing the computational cost to that of the accumulation of a molecular dynamics trajectory, and therefore cutting the overhead costs associated with the explicit calculation of the dipole moment and polarizability tensor. Our method permits to interpret the peaks in the spectrum in terms of local modes, also including the bending region. The results for the water-air interface, obtained usi…
Vortex-glass transition in three dimensions.
1991
We investigate the possibility of a vortex-glass transition in a disordered type-II superconductor in a magnetic field in three dimensions by numerical studies of a simplified model. Monte Carlo simulations at finite temperature and domain-wall renormalization-group calculations at {ital T}=0 indicate that {ital d}=3 is just above the lower critical dimension {ital d}{sub {ital l}}, though the possibility that {ital d}{sub {ital l}}=3 cannot be definitely ruled out. A comparison is made with {ital XY} and Ising spin glasses. The (effective) correlation-length exponent {nu} and dynamical exponent {ital z} are in fairly good agreement with experiment.
Tricritical universality in a two-dimensional spin fluid
1995
Monte Carlo simulations are used to investigate the tricritical point properties of a 2d spin fluid. Measurements of the scaling operator distributions are employed in conjunction with a finite-size scaling analysis to locate the tricritical point and determine the directions of the relevant scaling fields and their associated tricritical exponents. The scaling operator distributions and exponents are shown to match quantitatively those of the 2d Blume-Capel model, confirming that both models belong to the same universality class. Mean-field calculations of the tricritical point properties are also compared with the simulation measurements.
Longitudinal counterflow in turbulent liquid helium: velocity profile of the normal component
2013
In this paper, the velocity profile of the normal component in the stationary flow of turbulent superfluid helium inside a cylindrical channel is determined, making use of a one-fluid model with internal variables derived from Extended Thermodynamics. In the hypothesis of null barycentric velocity of the fluid (the so-called counterflow situation) it is seen that, in the presence of a sufficiently high vortex length density, the velocity profile of the normal component becomes very flat in the central region of the channel. Thus, a central flat profile of the normal fluid does not necessarily imply that the flow of the normal component is turbulent.
Convective Instability in a Horizontal Porous Channel with Permeable and Conducting Side Boundaries
2013
Published version of an article in the journal: Transport in Porous Media. Also available on Science Direct: http://dx.doi.org/10.1007/s11242-013-0198-y The stability analysis of the motionless state of a horizontal porous channel with rectangular cross-section and saturated by a fluid is developed. The heating from below is modelled by a uniform flux, while the top wall is assumed to be isothermal. The side boundaries are considered as permeable and perfectly conducting. The linear stability of the basic state is studied for the normal mode perturbations. The principle of exchange of stabilities is proved, so that only stationary normalmodes need to be considered in the stability analysis.…
Finite renormalization effects in the induceds¯dHvertex
1986
The finite renormalization contributions to the s-bard-italicH-italic vertex are examined in the standard model. They are explicitly shown to cancel each other among diagrams, so that the lower bound on the Higgs-boson mass M-italic/sub H-italic/>325 MeV is not affected by such effects.
The Influence of Particular Modes of Vibration
1986
When vibration stress occurs at the place of work, 1, 2, or 3 directions of the coordinate system related to man, or vectors of these axes, can be involved (Fig. 1). In such multiaxial vibration, the stress may predominate in one direction or may have similar magnitudes in all directions. In addition, rotational vibration about these axes may also take place (see section “Rotational Vibration,” p. 125).
Precision Spectroscopy of Deeply Bound Pionic Atoms and Partial Restoration of Chiral Symmetry in Medium
2011
We study theoretically the formation spectra of deeply bound pionic atoms expected to be observed by experiments with high energy resolution at RIBF/RIKEN, and we discuss in detail the possibilities to extract new information on the pion properties at finite density from the observed spectra, which may provide information on partial restoration of chiral symmetry in medium. We find that the non-yrast pionic states such as 2s are expected to be seen in the (d,3He) spectra, which will be helpful to reduce uncertainties of the theoretical calculations in the neutron wave functions in nucleus. The observation of the 2s state with the ground 1s state is also helpful to reduce the experimental un…