The European Physical Journal B最新文献

The canonical-ensemble description of homogeneous reactive quantum gas mixtures is reformulated by incorporating a single global particle-number conservation constraint over the combined spectra of interconverting species. This constraint replaces the conventional equality of chemical potentials. Fermi–Dirac or Bose–Einstein correlations naturally emerge across one-particle energy eigenstates of species sharing identical spin statistics, which in ergodic single systems manifest as intrinsic features of the equilibrium state. By embedding all microstates linked by conversion pathways, the framework incorporates concentration fluctuations in the statistical description. The formalism offers fresh insights into quantum chemical equilibrium in reactive mixtures with composition fluctuations and smoothly reduces to the classical ideal gas limit via an extended partition function that generalizes classical chemical-equilibrium treatments.

We theoretically propose a one-dimensional electronic nanodevice inspired in recently fabricated semiconductor–superconductor–ferromagnetic insulator (SE-SC-FMI) hybrid heterostructures, and investigate its subgap transport properties. While previous related studies have primarily focused on the potential for generating topological superconductors hosting Majorana fermions, we propose an alternative application for these devices: to generate tunable spin-polarized Andreev bound states (ABS) with potential uses in the design of spintronic devices. The proposed setup allows to controllably explore and detect the subgap ABS and to identify the associated spin- and parity-changing transitions in tunnel transport experiments. Our study highlights two key differences from existing devices: first, the length of the FMI layer must be shorter than that of the SE-SC heterostructure, introducing an inhomogeneous Zeeman interaction with significant effects on the induced ABS. Second, we focus on semiconductor nanowires with minimal or no Rashba spin-orbit interaction, allowing for the induction of spin-polarized ABS and high-spin quantum ground states. We show that the device can be tuned across spin- and fermion parity-changing transitions by adjusting the FMI layer length and/or by applying a global back gate voltage, with zero-energy crossings of subgap ABS as signatures of these transitions. Our findings suggest that these effects are experimentally accessible and offer a robust platform for studying and controlling spin-polarized ABS and quantum phase transitions in hybrid nanowires.

The equilibrium behaviours of a trilayered 6-state clock model have been investigated by Monte Carlo simulation. The intralayer interaction is considered ferromagnetic, whereas the interlayer interaction is antiferromagnetic. Periodic boundary conditions (PBC) are applied in XY plane and open boundary condition (OBC) is applied along Z-direction. The thermodynamic behaviours of sublattice magnetisation, total magnetisation, magnetic susceptibility and the specific heat are studied as functions of the temperature. The interesting compensation phenomenon, when the total magnetisation vanishes keeping the nonzero sublattice magnetisations, has been observed. The compensation temperature and the critical temperature are found to depend on the strength of single-site anisotropy. The comprehensive phase diagram is shown in the temperature-anisotropy plane. The larger systems show the growth of the height of the peak of the susceptibility near the critical temperature.