Modern Physics Letters A

Understanding the equation of state of dense nuclear matter is a fundamental challenge for nuclear physics. It is an especially timely and interesting challenge as we have reached a period where neutron stars, which contain the most dense nuclear matter in the Universe, are now being studied in completely new ways, from gravitational waves to satellite-based telescopes. We review the theoretical approaches to calculating this equation of state which involve a change in the structure of the baryons, along with their predictions for neutron star properties.

In this note, we revise the problem of the axial anomaly in the framework of Very Special Relativity following Fujikawa’s path integral approach. We show nonperturbatively that no VSR contribution is present in the path integral measure in (3 + 1)-dimensional spacetime. Furthermore, we extend our results to (1 + 1) dimensions, as well as to the two-dimensional curved spacetime.

In this paper, we investigate the Sharma–Mittal holographic dark energy (SMHDE) model in the context of a spatially homogeneous and isotropic flat Friedmann–Robertson–Walker (FRW) Universe by taking various values of model parameters $R$ and $\delta$ and the Hubble horizon is taken as the infrared cut-off. We have analyzed the deceleration parameter $(q)$ and the EoS parameter. According to the deceleration parameter, the Universe is in an accelerating and expanding phase, which is compatible with the observational data. The EoS parameter depicts that presently the Universe is lying in the quintessence region and at a late time it will show $\mathrm{\Lambda }$CDM behavior. It is also concluded by the stability analysis that SMHDE model is classically stable at present and future. To understand the dynamics of our Universe, we have established a correspondence among SMHDE and the quintessence, tachyon and K-essence scalar-field models. Our results show that the Universe is in an accelerating expansion mode described by quintessence like behavior. We go further and estimate the model parameters by using the distance modulus measurement of the recent Union 2.1 dataset of supernovae.

In this paper, we aim to generalize the constant-roll inflation in the noncanonical set-up, in the context of scalar Dirac–Born–Infeld (DBI) theory. Assuming the simplest case, when the speed of sound of scalar fluctuations is constant, we obtain exact inflationary solutions under constant-roll conditions. We finally provide an observational bound to constrain the DBI constant-roll parameter by using the values of scalar spectral index and speed of sound provided by Planck and WMAP data.

The intrinsic level-density parameters in natural radioactive nuclei, which emit alpha particles, have been extracted within a microscopic formalism based on the BCS model with inclusion of pairing interaction. Then, total level-density parameters considering the collective effects are obtained. In addition, the level-density parameter excess of total level-density parameter compared to the intrinsic level-density parameter as a function of excitation energy has been determined for each nucleus. A cusp in the level-density parameter excess is observed at energies about neutron binding energy for prolate deformed nuclei with ${\beta }_2>0.15$. However, the level-density parameter excess behavior is quite incremental for the considered nuclei with ${\beta }_2<0.15$.

In this paper, we solve exactly the Schrödinger equation for the free-particle, the pseudo-harmonic oscillator and the Mie-type potential in three dimensions with the Dunkl derivative. The equations for the radial and angular parts are obtained by using spherical coordinates and separation of variables. The wave functions and the energy spectrum for these potentials are derived in an analytical way and it is shown that our results are adequately reduced to those previously reported when we remove the Dunkl derivative parameters.

The aim of this paper is to quantify the quantum correlations between mechanical and optical modes in an optomechanical system with two spatially separated Fabry–Pérot cavities. We use logarithmic negativity $(E_N)$ and entanglement of formation (EoF), respectively, to quantify entanglement between optical and mechanical modes, while Gaussian geometric discord (GGD) is used to capture all nonclassical correlations, including entanglement. These quantifiers are evaluated as functions of the physical parameters characterizing the environment and the system (the thermal bath temperature $T$, the photons number $n_{\mathrm{\text{th}}}$, the optomechanical cooperativity $C$, the squeeze parameter $r$ and the drive pump power $P$). By considering recent experimental parameters, we show that GGD is more robust than entanglement for high thermal bath temperature and low optomechanical cooperativity. We also find that these quantifiers improve with increasing optomechanical cooperativity. The effects of the other parameters are also discussed in detail.