Description of the viscosity of honeys in the supercooled regime

For several honeys from different countries, we study the dependence of the Logarithmic Shift Factor (LSF$LSF$) with temperature that obeys the Williams–Landel–Ferry equation. We find that the LSF$LSF$ may be expressed in terms of a linear equation. On the other hand, the viscosities of different honeys present a corresponding state behavior through a master plot in terms of an adimensional temperature. This kind of behavior has been reported for other glass formers.     

Thermal entanglement of a two-level atom and bimodal photons in a Kerr nonlinear coupler

In this paper thermally induced entanglement between a two-level atom and photons inside a bimodal nonlinear coupler is studied. The interaction occurs in the presence of a centrosymmetric medium which couples the two photonic modes via the first and third order susceptibilities. Such effects on the atom–photons interaction, however, are assumed negligible so that the linear Jaynes–Cummings model applies. It is further assumed that the coupler is held at a temperature T$T$, so that each of the combined atom–photon states, with a definite, T$T$ dependent, probability, is present. The partially transposed density matrix and, consequently, the negativity, as a measure of entanglement, are determined as functions of temperature. The negativity so calculated shows that the system of a two-level atom and photons is separable at zero temperature, becomes more entangled, reaching the maximal at a certain temperature and asymptotically disentangles. Effect of medium characteristics on such behavior is also discussed.     

Confined helium: Excited singlet and triplet states

Energies for the first four singlet and triplet S states of a helium atom confined at the center of an impenetrable sphere are reported. All calculations used explicitly correlated Hylleraas basis sets. The first triplet state is shown to lie below the first excited singlet state only when the confinement radius is greater than 0.988_a0$0.988a_0$. A simple configuration interaction calculation was performed in parallel with Hylleraas calculation. The one-electron atomic orbitals of the configuration treatment provide insight into the physical concepts behind the numerical results of the Hylleraas treatment. This was particularly helpful in understanding the level crossing and avoided crossings observed with changing confinement radius.     

The temperature dependent amide I band of crystalline acetanilide

The temperature dependent anomalous peak in the amide I band of crystalline acetanilide is thought to be due to self-trapped states. On the contrary, according to the present model, the anomalous peak comes from the fraction of ACN molecules strongly hydrogen-bonded to a neighboring ACN molecule, and its intensity decreases because, on average, this fraction decreases as temperature increases. This model provides, for the first time, an integrated and theoretically consistent view of the temperature dependence of the full amide I band and a qualitative explanation of some of the features of nonlinear pump–probe experiments.     

Interplay of negative pressure and hydrogen chemical effects in CeRhSn from first principles

Investigations within the local spin density functional theory (LSDF) of the intermetallic hydride system CeRhSnH_x were carried out for discrete model compositions in the range 0.33 ≤x_H ≤ 1.33 with the purpose of assessing the change of the cerium valence state in the neighborhood of the experimental hydride composition, CeRhSnH_0.8. In agreement with experiment, the analyses of the electronic and magnetic structures and of the chemical bonding properties point to trivalent cerium for 1 ≤x_H ≤ 1.33. In contrast, for lower hydrogen amounts the hydride system stays in an intermediate-valent state for cerium, like in CeRhSn. The influence of the insertion of hydrogen is addressed from both the volume expansion and chemical bonding effects. The latter are found to have the main influence on the change of Ce valence character. Spin polarized calculations point to a finite magnetic moment carried by the Ce 4f states; its magnitude increases with x_H in the range 1 ≤x_H ≤ 1.33.     

Superposition of Coherent States in a Mesoscopic Josephson Junction with Dissipation

A mesoscopic Josephson junction with dissipation is considered. Usually the dissipation in the system is described as a consequence of its coupling to a reservoir. By solving the master equation we show that the state of the junction can evolve in a quantum superposition of two coherent states even when the dissipation is present.``