Modern Physics Letters A

Recent advances in applying thermodynamic ideas to quantum systems have raised the novel prospect of using non-thermal, non-classical sources of energy, of purely quantum origin, like quantum statistics, to extract mechanical work in macroscopic quantum systems like Bose–Einstein condensates. On the other hand, thermodynamic ideas have also been applied to small systems like single molecules and quantum dots. In this paper, we study the quantum thermodynamics of small systems of anyons, with specific emphasis on the quantum Otto engine which uses, as its working medium, just one or two anyons. Formulae are derived for the efficiency of the Otto engine as a function of the statistics parameter.

The Algebraic Cluster Model (ACM) is an interacting boson model that gives the relative motion of the cluster configurations in which all vibrational and rotational degrees of freedom are present from the outset. We schemed a solvable extended transitional Hamiltonian based on affine $\mathrm{\text{SU}}(1,1)$ Lie algebra within the framework for two-, three- and four-body algebraic cluster models that explains both regions $O(4)\leftrightarrow U(3)$, $O(7)\leftrightarrow U(6)$ and $O(10)\leftrightarrow U(9)$, respectively. We offer that this method can be used to study $k\alpha +x$ nucleon structures with $k=2,3,4$ and $x=1,2,\dots ,$ in specific $x=1,2$ such as structures ${}^9\mathrm{\text{Be}}$, ${}^9\mathrm{\text{B}}$, ${}^{10}\mathrm{\text{B}}$; ${}^{13}\mathrm{\text{C}}$, ${}^{13}\mathrm{\text{N}}$, ${}^{14}\mathrm{\text{N}}$; ${}^{17}\mathrm{\text{O}}$, ${}^{17}\mathrm{\text{F}}$. Numerical extraction to the energy levels, the expectation value of the boson number operator, and the behavior of the overlap of the ground state wave function within the control parameters of this evaluated Hamiltonian are presented. The effect of the coupling of the odd particle to an even–even boson core is discussed along the shape transition and, in particular, at the critical point.

This study investigates the dynamics of a spatially homogeneous and anisotropic LRS Bianchi type-I Universe with viscous fluid in the framework of $f(Q)$ symmetric teleparallel gravity. We assume a linear form for $f(Q)$ and introduce hypotheses regarding the relationship between the expansion and shear scalars, as well as the Hubble parameter and bulk viscous coefficient. The model is constrained using three observational datasets: the Hubble dataset (31 data points), the Pantheon SN dataset (1048 data points), and the BAO dataset (6 data points). The calculated cosmological parameters indicate expected behavior for matter-energy density and bulk viscous pressure, supporting the universe’s accelerating expansion. Diagnostic tests suggest that the model aligns with a $\mathrm{\Lambda }$CDM model in the far future and resides in the quintessence region. These findings are consistent with recent observational data and contribute to our understanding of cosmic evolution within the context of modified gravity and bulk viscosity.

In this paper, we study the one-parameter $\kappa$-generalized oscillator algebra ${{𝒜}}_{\kappa }$ (which includes the case of the standard Weyl–Heisenberg algebra). This algebra admits representations of finite-dimensional for negative values of the parameter $\kappa$. We construct the associated Perelomov like coherent states. We discuss their statistical properties. In particular, we derive the expressions of the Mandel parameter and Husimi function and we discuss the squeezing of the ${{𝒜}}_{\kappa }$ coherent states.

A sketchy review of the “island” paradigm in black hole evaporation theory, which actually brings us back to the old idea that interior of black hole decouples from our universe after Page time, so that Hawking radiation is entangled with emerging new universe, thus leaving no room for the information paradox. Instead this provides a self-consistent description of multiverse, where every black hole in a parent universe is a white hole — the origin — of a new one.

In the framework of $f(R,T,R_{ab}{T}^{ab})$ gravity theory, the slow-roll approximation of the cosmic inflation is investigated, where T is the trace of the energy–momentum tensor $T^{ab}$, R and $R_{ab}$ are the Ricci scalar and tensor, respectively. After obtaining the equations of motion of the gravitational field from the action principle in the spatially flat FLRW metric, the fundamental equations of this theory are received by introducing the inflation scalar field as the matter and taking into account only the minimum curvature-inflation coupling term. Remarkably, after taking the slow-roll approximation, the identical equations as in $f(R,T)$ gravity with a $RT$ mixing term are derived. We study several potentials of interest in different domains. We perform analytical analyzes under various approximate conditions, and present numerical results and their comparison with existing observational data at the same time. In the appendix, we analyze the behavior of the inflation scalar field under perturbation while ignoring the effect of metric perturbations. This research complements the slow-roll inflation in the modified theory of gravity.

In this paper, we study the 2D Euler equations for Chaplygin gas, which is a model for dark energy of the universe in some of cosmology theories. By using an ansatz developed by Yuen, we present some rotational and self-similar analytical solutions. We obtain the global existence of the constructed solutions and investigate the qualitative properties of the gas density according to various parameters.