Modern Physics Letters B

The article describes the quantum properties of mode-locked two-photon state generated through either a Fabry–Perot cavity or a sub-threshold optical parametric oscillator. It is shown that the time correlation function of such a state exhibits a comb-like structure. Different approaches to observe this comb-like feature are thoroughly discussed. The experiment demonstrates several different quantum interference effects with a mode-locked two-photon state. An analysis of the experiment leads to a new control technique of two-photon interference and to a better understanding of time-entangled two-photon state. A novel quantum information coding is predicted if such a state is mixed with a single-mode wide band two-photon state.

Cut Fe₄₀Ni₃₈B₁₈Mo₄ ribbons were annealed for two hours at various temperatures T_a between 400 and 540°C. All the ribbons were subjected to XRD, VSM (vibrating sample magnetometer) and ME (Mossbauer effect spectroscopy) investigations. A differential thermal analysis scan of an as-cast ribbon showed the presence of two exothermic peaks, the first beginning at 419.9°C and peaking at 429.7°C and the second beginning at 497.3°C and ending at 546.2°C. The XRD patterns of the ribbons showed the formation of FeNi₃ nanocrystallites in the lower T'_a ribbons and (Fe, Ni, Mo)₂₃B₆ crystallites in the ribbons annealed above 470°C. Different behaviors of the saturation magnetization were seen in the ribbons annealed between 400 and 450°C, between 450 and 490°C, and between 490 and 540°C. The ME spectra of the ribbons annealed in the three different temperature ranges also pointed to the presence of three crystalline Fe-compounds in these ranges. The XRD patterns and the coercivities (H_c) of the lower T_a ribbons point to the formation of nanocrystallites in these ribbons.

For the Bose-condensed gas in a one-dimensional optical lattice, several far-off resonant laser beams are used to split and trap the matter wavepacket after switching off both the magnetic trap and optical lattices. In the presence of two far-off resonant laser beams which are not symmetric about the centre of the matter wavepacket, we propose an experimental scheme to observe the collision between two side peaks after switching off the magnetic trap and optical lattice. We also discuss an experimental scheme to realize a coherent splitting and trapping of the matter wavepacket which has potential application in atom optics.

In-situ high-pressure energy dispersive X-ray diffraction measurements on CuBa₂-Ca₃Cu₄O_{10 + δ}(Cu-1234) have been performed by using diamond anvil cell (DAC) device with synchrotron radiation. The results suggest that the crystal structure of Cu-1234 superconductor is stable under pressures up to 34 GPa at room temperature. According to the Birch–Murnaghan equation of state, the bulk modulus is obtained to be ~ 150 GPa.

LaMn_1-xCu_xO₃ compounds have been prepared in single phase form for x = 0 to 0.30. X-ray diffraction patterns recorded at room temperature could be mostly refined using Pbnm space group. Paramagnetic-to-ferromagnetic transitions have been observed up to x = 0.30, from ac susceptibility measurements. Metal–insulator transition in the vicinity of ferromagnetic transition temperature has been observed for x = 0.05 and the resistivity data in the metallic region could be explained in terms of electron–electron and electron–magnon scattering mechanisms. Further increase in Cu-doping beyond x = 0.05 leads to systematic decrease in ferromagnetic transition temperature and ultimately ferromagnetism is destroyed for x = 0.40. The resistivity data of all samples except x = 0.05 exhibit semiconducting behaviors and they could be mostly explained using the adiabatic small polaron hopping model.

In the present work, the magnetic properties of high-T_cBi_1.7Pb_0.3Sr₂Ca_2-xSm_xCu₃O₁₂ system (x = 0.03) have been investigated, for different temperatures below T_c. Substitution of Sm³⁺ for Ca²⁺ is found to change the superconducting properties of the system, despite the weak paramagnetic nature of the Sm³⁺ ion. The dc magnetization measurements performed on the compound reveal that the superconducting regions decrease with increasing temperature and magnetic field. The results are explained on the basis of a possible reduction of hole concentration with trivalent rare-earth ion substitution, and also on the basis of the magnetic nature of the substituted Sm³⁺ ions.