Modern Physics Letters B

We solve various master equations to obtain density operators' infinite operator-sum representation via a new approach, i.e., by virtue of the thermo-entangled state representation that has a fictitious mode as a counterpart mode of the system mode. The corresponding Kraus operators from the point of view of quantum channel are derived, whose normalization conditions are proved. Miscellaneous characters possessed by different quantum channels, such as decoherence, phase diffusion, damping, and amplification, can be shown explicitly in the entangled state representation of the density operators. Squeezing transformation is applied to the density operator for decoherence to generate a master equation for describing the phase sensitive process. Partial trace method for deriving new density operators is also introduced. Throughout our discussion, the technique of integration within an ordered product (IWOP) of operators is fully used.

In this letter, the results on the development and simulation of new three-dimensional nanotraps for cold dressed atoms are considered. The traps are the multi-cell structures built by crossed non-touching carbon or metallic nanotubes. The trapping effect is tuned by the DC and RF currents to confine the strong- or low-potential seeking atoms far enough from the areas of strong Casimir–Polder and spin-flip forces. It is supposed that the developed and simulated multi-cell structures are pertinent for catching the Bose–Einstein condensates to demonstrate the Josephson effect, and to enable the study of the entanglement of confined clouds in three-dimensional nano-cells.

We present theoretical expressions relating the cohesive energy to the bulk modulus, the force constant and the lattice constant applicable to solids with a variety of crystal structures. We have found that the cohesive energy is directly proportional to the ratio between the product of the bulk modulus through the atomic volume and the exponent of the repulsion term. We have defined a figure of merit for materials as the ratio between the product of the bulk modulus through the atomic volume and the cohesive energy. The reciprocal of this ratio is a measure of the hardness of materials. Likewise, we have found the expressions for anharmonicity and thermal expansion coefficients, which can explain, also, their possible negative values.

Multiwalled carbon nanotubes (MWCNTs) were dispersed in various alcohols such as methanol, ethanol and isopropanol using ultrasonication. In order to disperse the MWCNTs in the alcohols, they were treated using a mixture of H₂SO₄ and HNO₃ (3 : 1, vol/vol). The concentration of MWCNTs was approximately 0.03 wt.% and they formed a homogeneous dispersion in the alcohol solutions. The functional groups introduced on the surface of the MWCNTs during the acid treatment were characterized by Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy. The dispersibility of the MWCNTs in the alcohols was characterized using atomic force microscopy, scanning electron microscopy and transmission electron microscopy. The stability of the MWCNT dispersions was also measured using a recently developed optical analyzer (Turbiscan).

Based on the exactly analytic solution obtained of the intensity-dependent Jaynes–Cummings model for a certain class of initial entangled mixed states, we explore the time evolution of the entanglement between two atoms, initially non-locally correlated and separately interacting with two distinct cavities. The results show that entanglement sudden death is dependent on the different initial states of atoms, and the length of the time interval for the zero entanglement is invariant for a certain class of initial mixed states.

Recently the universal behavior of the temperature dependent enthalpy of vaporization along with the whole liquid–vapor coexistence curve at equilibrium is described and explained by Roman et al.⁵ The work (called RWVM relation) succeeds in the combination of the linear relation near the triple point and the renormalization group theory result near the critical point. For the convenience of chemical designs and engineering applications, we report its b values yielding the minimum average absolute deviation (AAD) for 74 pure substances from the NIST web-book and compare the results with other correlations. We find that with an adapted b value, the RWVM relation predicts the data of 47 pure substances with an AAD less than 0.0093, with six more than 0.02 and all less than 0.03 except quantum fluid hydrogen, that is clearly better than other correlations. For most pure substances, b covers the range from 0 to 1. Only one negative value stands for the quantum fluid helium because of its enthalpy of vaporization being experimentally not a monotonic function of the temperature in the range near the triple point.

The composites with the nominal composition of (1-x)La_0.67Sr_0.33MnO₃ (LSMO)/xCeO₂ were fabricated by the sol–gel method. A special electrical transport behavior is observed in the ρ/ρ_Tp versus temperature curves, where ρ_Tp is the peak resistivity at the insulator–metal transition temperature (T_p). The curves for all samples with different CeO₂ content are parallel in the high-T insulator regime and in a certain temperature range below T_p. Furthermore, a series of parallel straight lines can be found in the versus temperature curves for the samples with different CeO₂ content. By considering the surface magnetization at the grain boundary, we obtain a simple expression for the temperature dependence of resistivity that can reproduce the experimental data in the high-T insulator regime and in a certain temperature range below T_p.

Two forms of the three-qubit pure state for teleporting an unknown one-particle entangled state are presented, where the successful possibilities and fidelities of the two schemes both reach one unit. It is worthwhile noticing that GHZ states and W-states are special cases of those two forms of a perfect quantum channel. Furthermore, the orthogonal complete measurement bases are given.