Modern Physics Letters A

In this paper, we will describe recent advances in analytical methods to construct exact solutions of the Skyrme model (and its generalizations) representing inhomogeneous Hadronic condensates living at finite Baryon density. Such novel analytical tools are based on the idea to generalize the well-known spherical hedgehog ansatz to situations (relevant for the analysis of finite density effects) in which there is no spherical symmetry anymore. Besides the intrinsic mathematical interest to find exact solutions with nonvanishing Baryonic charge confined to a finite volume, this framework opens the possibility to compute important physical quantities which would be difficult to compute otherwise.

In this paper, the origin of disentanglement for two specific sub-classes of $X$-states namely maximally nonlocal mixed states (MNMSs) and maximally entangled mixed states (MEMSs) is investigated analytically for a physical system consisting of two spatially separated qubits interacting with a common vacuum bath. The phenomena of entanglement sudden death (ESD) and the entanglement sudden birth (ESB) are observed, but the characteristics of ESD and ESB are found to be different for the case of two-photon coherence and single photon coherence states. The role played by initial coherence for the underlying entanglement dynamics is investigated. Further, the entanglement dynamics of MNMSs and MEMSs under different environmental noises namely phase damping, amplitude damping and random telegraph noise (RTN) noise with respect to the decay and revival of entanglement is analyzed. It is observed that the single photon coherence states are more robust against the sudden death of entanglement, indicating the usability of such states in the development of technologies for the practical implementation of quantum information processing tasks.

Broadcast and multicast protocols are two branches of multi-party quantum communication. Implementing these protocols based on partial entanglement is of great practical importance since maximally entangled channels are not robust due to noise applied by the surrounding environment. Previous research has used global operators (i.e. operators which are applied on the qubits owned by different parties), which contradicts the concept of multi-party communication protocols. In this research, broadcast protocol and multicast protocol with two receivers are proposed using partially entangled channels. Then the protocols are extended to the case with an arbitrary number of receivers. In the proposed protocol, Alice shares a two-qubit maximally entangled state with each receiver, therefore the whole channel is a partially entangled state. Then, the proposed protocol is modified to be secure against eavesdroppers. Also, the effects of phase damping, bit flip, and phase damping noise on the broadcast protocol are examined and compared.

The inflationary 1-loop tensor power spectrum from a spectator scalar field with a sharp peak is calculated. Recent studies on primordial black holes suggest that the inflationary curvature perturbation may be huge on small scales. An enhanced curvature perturbation may arise from a drastic enhancement of spectator scalar field fluctuations. In this paper, using the in-in formalism, we calculate 1-loop quantum corrections to primordial gravitational waves by such a spectator field with a sharp peak in momentum space. We find scale-invariant loop corrections in this full quantum setup, in contrast to the sharply peaked corrections in the previously calculated scalar-induced tensor modes. Especially on super Hubble scales, the primordial gravitational waves are also amplified, which can be understood as a Bogoliubov transformation of the vacuum due to the enhanced scalar field. This mechanism allows us to probe the scalar field properties on extremely short-distance scales with the current and future cosmic microwave background and gravitational wave experiments, opening a novel window for inflationary cosmology.

Composite particle, ${(}^{3}He,t)$, charge exchange reactions on targets ${}^{12}C$, ${}^{13}C$, ${}^{18}O$, ${}^{26}Mg$, ${}^{58}Ni$ and ${}^{118,120}Sn$ at 140 MeV/u beam energy have been analyzed by employing distorted wave impulse approximation (DWIA). Specifically, unit cross-section and angular distribution have been calculated using normal optical model potential (NOMP) and single folding optical model potential (SFOMP) for both relativistic and non-relativistic cases. The sensitivity of present results on exchange terms has also been examined and it is pertinent to report here that the inclusion of these effects reduces the cross-section in magnitude up to 60%, which in turn brings it closer to the data except for ${}^{12}C$.

In this paper, we highlight the variables preserving stability of a very restricted class of anisotropic axial symmetrical compact geometry in the scenario of $f(R,T)$ gravity, where $T$ stands for energy–momentum tensor’s trace and $R$ is invariant Ricci curvature. In the framework of $f(R,T)$ gravity, we set up field equations as well as non-conservation equations. We use a perturbation technique for all variables involved in non-conservation equations, field equations, extra curvature terms of modified gravity as well as for considered gravity model (i.e. $f(R,T)=R+\zeta R^n+\chi T$) to evaluate the collapse equation. We establish certain significant constraints for the stiffness parameter $\mathrm{\Gamma }$ in Newtonian $({𝒩})$ and post-Newtonian $({𝒫}{𝒩})$ approximation to study the dynamical instability of a stellar compact configuration. In order to preserve the stability of an anisotropic self-gravitating axially symmetric configuration, we place certain restrictions on physical quantities. To examine the stable and unstable behavior of considered geometry via graphical approaches, we include schematic diagrams at the ${𝒩}$ and ${𝒫}{𝒩}$ eras.

In this paper, we have suggested that the late time expansion of the Universe is caused by the absorption of baby universes. This absorption leads to a modified Friedmann equation with one free parameter B replacing the cosmological constant. The late time cosmology is modified in such a way that one can obtain agreement with the measured values of the Hubble parameter H(z) for z between 0 and the value corresponding to the time of last scattering of CMB for a suitable choice of B. In this paper, we show that the modified Friedmann equation with this choice of B also describes well other aspects of the large-scale structure of the Universe.

Quantum Natural Language Processing (QNLP) is coded in the semantic space using a combined semantic distribution classification model with tensor operations. Its theoretical results on quantum circuit mapping and quantum semantic coding of text have been tested in practice with the recent development of quantum back-end equipment. In view of the small scale of quantum natural language processing tasks, single sentence structure of quantum semantic coding, low text coverage and lack of application, this paper proposes a combination of syntactic structure to extract text and extend the sentence components of quantum semantic coding, which improves the utilization of text processing task of quantum computing resources. In view of the fact that quantum natural language processing has few cases in specific applications, this paper studies the application expansion possibility of quantum text matching and question answering applications. The development path of classical natural language processing is referred to enhance the usefulness and explore the practical ability of QNLP in the current resource-constrained conditions.