Modern Physics Letters B

The time-dilations that arise during quantum tunneling appear applicable to the time-translation thought experiment by Aharonov et al. It may be feasible to actually perform a test for communicating in reverse-time as described by Cramer.

A new model is proposed to study the effect of mutual interaction revealed in a recent experiment.¹ Unlike conventional Hartree–Fock theory, which only studies onset interactions between indistinguishable interacting bosons, our model further includes the mutual interaction between the condensate component and the thermal component. The derived condensate fraction and transition temperature explain the experimental data in a reliable manner.

Based on the elasto-/hydro-dynamic model the dynamic properties of the five-fold symmetry quasicrystals with point groups 5, are investigated, by using the finite difference method. The problems including dynamic initiation of crack growth and fast crack propagation of this material are studied. The results show that the phonon–phason coupling effect plays an important role to the dynamic properties of the quasicrystals.

Frobenius integrable decompositions are introduced for partial differential equations with variable coefficients. Two classes of partial differential equations with variable coefficients are transformed into Frobenius integrable ordinary differential equations. The resulting solutions are illustrated to describe the solution phenomena shared with the KdV and potential KdV equations, the Boussinesq equation and the Camassa–Holm equation with variable coefficients.

An experimental approach is employed by using transparent electrodes to investigate the column size distribution where an external electric field applied to a colloidal suspension is increased. The coarsening profile of ER suspension is strongly related to field strength, but is insensitive to particle size. In addition, the interaction among the suspended particles, i.e. the shear stress, corresponding to the mean column diameter is studied and the power-law dependence is found at low field range. However, this dependence is not valid when the field strength surpasses a threshold value.

Spin density waves (SDWs) may be thought of as comprising charge density waves (CDWs) in pairs, with one CDW composed of up-spin electrons and the other composed of down-spin electrons. The superconductivity in cuprates may then be said to be caused by the BCS-type pairing of these SDWs. This is no longer a simple Cooper pairing of singlet electrons but one that involves a collection of Cooper pairs. Transport in normal metallic states is then governed by CDW pinning, as in a quantum well that is characterized by linear temperature dependence. The pseudo-gap may be understood as originating from this BCS-type gap with SDW, where the parameters used are from those of the original BCS scheme except that the electron–electron interaction is multiplied by N_CDW, which is the number of electrons that have the same spin direction belonging to one CDW branch of the pair that comprises the SDW.

In this paper, we propose a scheme to implement two-qubit Deutsch–Jozsa algorithm with trapped ions. The distinct advantage of the scheme lies in the fact that it does not use the vibrational mode as the data bus. The vibrational mode is only virtually excited, which makes our scheme insensitive to heating provided that the system remains in the Lamb–Dicke regime.

The ground state lifetime of a magnetopolaron was investigated with electron–LO-phonon strong coupling in an asymmetric quantum dot using the linear combination operator and unitary transformation methods. Quantum transition, which cause changes of the magnetopolaron lifetime, occurs in the quantum system due to electron–phonon interaction and the influence of external temperature, that is, the magnetopolaron leaps from the ground state to the first excited state after absorbing a LO-phonon. The expressions of the ground state lifetime of the magnetopolaron as a function of the ground state energy, the transverse and longitudinal confinement lengths of quantum dot, the electron–phonon coupling strength, the cyclotron vibration frequency and the external temperature were obtained. Numerical calculations have been performed and the results show that the ground state lifetime of the magnetopolaron increases with increasing the ground state energy and the cyclotron vibration frequency, and decreases with increasing the transverse and longitudinal confinement lengths of the quantum dot, the coupling strength and the external temperature.

Hf:Fe:LiNbO₃ crystals were grown by the Czochralski technique with various ratios of Li/Nb = 0.946, 1.05, 1.20 and 1.38 in the melt. The crystal composition and defect structure were analyzed by XRD, UV-Vis and IR spectroscopy. The results show that the threshold concentration of Hf in LiNbO₃ crystals decrease with the increasing of the Li/Nb ratio; when the Li/Nb ratio is 1.05, the threshold concentration of Hf is less than 2 mol%, largely under the threshold concentration of Hf ions in congruent Hf:Fe:LiNbO₃ crystal (4 mol).^1–3 With the increase of Li/Nb, Hf ions first replace the ; when the concentration of Hf ions is higher than the threshold value, Hf ions occurs on normal Nb and Li sites.

Primary shear horizontal (SH) mode propagation and its second harmonic are generated and detected using wedge transducers on the surface of an elastic plate. In the far field region, the clear second-harmonic response can be observed at the frequency where the phase velocity of the primary SH mode equals that of the symmetric double-frequency Lamb mode. Based on the measured results, the ratio of the second-harmonic amplitude to the square of the primary SH mode amplitude is numerically evaluated for different propagation distances. It is experimentally verified that under some conditions the second harmonic of the primary SH mode propagation grows in amplitude with propagation distance.

In this paper, based on the local preferential redistribution rule of the load after removing a node, we propose a cascading model and explore cascading failures on scale-free networks. Assuming that a failed node leads only to a redistribution of the load passing through it to its neighboring nodes, we study the response of scale-free networks subject to attacks on nodes. The network robustness against cascading failures is quantitatively measured by the critical threshold T_c, at which a phase transition occurs from normal state to collapse. For each case of attacks on nodes, four different attack strategies are used: removal by the descending order of the degree, attack by the ascending order of the degree, random removal of breakdown, and removal by the ascending order of the average degree of neighboring nodes of a broken node. Compared with the previous result, i.e. the robust-yet-fragile property of scale-free networks on random failures of nodes and intentional attacks, our cascading model has totally different and interesting results. On the one hand, as unexpected, choosing the node with the lowest degree is more efficient than the one with the highest degree when α < 1, which is a tunable parameter in our model. On the other hand, the robustness against cascading failures and the harm order of four attack strategies strongly depends on the parameter α. These results may be very helpful for real-life networks to protect the key nodes and avoid cascading-failure-induced disasters.

Single crystals of pure and various amount of L-lysine doped KDP crystals were grown from aqueous solution. The doping of L-lysine was confirmed by CHN analysis and FT-IR spectroscopy. Powder XRD was carried out to assess the single phase nature of the samples. The effect of doping on thermal stability of the crystals was carried out by TGA and the kinetic and thermodynamic parameters of dehydration were evaluated. It was found that as the amount of doping of amino acid, L-lysine, increased the thermal stability of the grown crystals decreased. However, the second-harmonic generation (SHG) efficiency of Nd:YAG laser and UV-vis spectroscopy studies indicated that as the L-lysine doping increased in KDP crystals the SHG efficiency and optical transmission percentage increased. The dielectric constant and the dielectric loss of L-lysine doped KDP crystals are lower than the pure KDP crystals. Hence L-lysine doped KDP crystals are found to be more beneficial from an application point of view as compared to pure KDP crystals. The results are discussed.

The spin diffusion coefficient tensor of the A₁-phase of superfluid ³He at low temperatures and melting pressure is calculated using the Boltzmann equation approach and Pfitzner procedure. Then considering Bogoliubov-normal interaction, we show that the total spin diffusion is proportional to 1/T², the spin diffusion coefficient of superfluid component is proportional to T^-2, and the spin diffusion coefficient of super-fluid component is independent of temperature. Furthermore, it is seen that superfluid components play an important role in spin diffusion of the A₁-phase.