Modern Physics Letters B

We review the results of specific-heat experiments on the S = 1 quasi-one-dimensional (quasi-1D) bond-alternating antiferromagnet Ni(C₉H₂₄N₄)(NO₂)ClO₄, alias NTENP. At low temperatures above the transition temperature of a field-induced long-range order, the magnetic specific heat (C_mag) of this compound becomes proportional to temperature (T), when a magnetic field along the spin chains exceeds the critical field H_c at which the energy gap vanishes. The ratio C_mag/T, which increases as the magnetic field approaches H_c from above, is in good quantitative agreement with a prediction of conformal field theory combined with the field-dependent velocity of the excitations calculated by the Lanczos method. This result is the first conclusive evidence for a Tomonaga–Luttinger liquid in a gapped quasi-1D antiferromagnet.

The Halting problem of a quantum computer is considered. It is shown that if halting of a quantum computer takes place the associated dynamics is described by an irreversible operator.

The purity of Werner state in non-extensive formalism associated with two different constraints has been calculated in a previous paper by Bağci et al.¹⁷ Two different results have been obtained corresponding to ordinary probability and escort probability. The former has been shown to result in negative values thereby leading authors to deduce the advantage of escort probabilities over ordinary probabilities. However, these results have only been for a limited interval of q values which lie between 0 and 1. In this paper, we solve the same problem for all values of non-extensive index q by using a perturbative approach and show that the simultaneous use of both types of constraint is necessary in order to obtain the solution for a whole spectrum of non-extensive index. In this sense, the existence of these different constraints in non-extensive formalism must not be seen as a deficiency in the formalism but rather must be welcomed as a means of providing solution for all values of parameter q.

The possibility to use poly(ethylene oxide) as a polymeric matrix for some pharmaceutical products was analyzed. The behavior of the polymer in the aqueous solutions and the possible interactions between the polymer and the clotrimazole were investigated by Raman spectroscopy. Repeated action of the water on the polymeric conformation is a reversible process and the introduction of the clotrimazole in the polymeric gel do not modify the properties of the active substance of the pharmaceutical product.

The oscillation of a cavitation bubble and the effect of gas content inside a cavity on the bubble motion are investigated by theory and experiment. Based on the cavitation model, the numerical study yields the gas content dependence of the amplitude and duration of the bubble oscillation in liquids. In experiment, the temporal oscillation of a single laser-induced cavitation bubble is obtained by means of a sensitive fiber-optic sensor based on optical beam deflection. The characteristic bubble parameters are determined, including the maximum (minimum) radii, oscillation duration and bubble energy, which all decrease with the oscillation. Besides, combining the cavitation theory with experimental data, the variation of gas content within the bubble during each oscillation is estimated, which increases with the oscillation cycle. Our results reveal the competitive interplay of the bubble energy and gas content during the bubble motion and the bubble energy in effect outweighs the latter.

We introduce a novel model for attack vulnerability of complex networks with a tunable attack information parameter. Based on the model, we study the attack vulnerability of complex networks based on local information. We employ the generating function formalism to derive the exact value of the critical removal fraction of nodes for the disintegration of networks and the size of the giant component based on local information. We show that hiding just a small fraction of nodes can prevent the breakdown of a network and that it is a cost-efficient strategy for enhancing the robustness of complex networks to hide the information of networks.

We investigate the spontaneous emission spectra of a coherently driven four-level cold atomic system. It is shown that a few interesting phenomena such as spectral-line narrowing, spectral-line enhancement, spectral-line suppression, and spontaneous emission quenching can be realized in our system. The spectral-line enhancement and suppression can be conveniently manipulated by appropriately modulating the frequency detuning of the probe driving field. In the dressed-state picture of the probe and coupling fields, we find that this coherently-driven atomic system has three close-lying levels so that multiple spontaneously-generated coherence (SGC) arises. Our considered atomic model can be found in real atoms, such as rubidium or sodium, so a corresponding experiment can be done to observe the expected phenomena related to SGC effect, since no rigorous conditions are required.

We conjecture that the evolution process with self-avoiding random walks is the origin for the properties of urban ground bus-transport networks (BTN). In order to verify our conjecture, a toy model, which simulates the growth of urban bus-transport systems, is proposed after empirical investigation on the BTNs of four major cities in China. In current empirical and simulation research, our method combining weight and geographical topology of the BTN together allows us to study the coupling relations among the BTN's weighted quantities and underlying topological structure. Finally, the simulating results reveal that the model can reproduce most phenomena observed in real-life urban ground BTNs.