Isospin- and momentum-dependent interaction in isospin-dependent quantum molecular dynamics

An isospin-dependent quantum molecular dynamical model （IQMD） is developed, with the isospin degree of freedom in the momentum-dependent interaction（MDI） included in IQMD, to obtain an isospin- and momentum-dependent interaction （IMDI） in IQMD. We investigate the effect of IMDI on the isospin fractionation ratio and its dynamical mechanism in the intermediate energy heavy ion collisions. It is found that the IMDI induces the significant reductions in the isospin fractionation ratio for all of beam energies, impact parameters, neutron-proton ratios and mass number of colliding systems. However, the strong dependence of isospin fractionation ratio on the symmetrical potential is preserved, with the isospin degree of freedom included in the MDI, i.e. the isospin fractionation ratio is still a good probe for extracting the information about the equation of state of isospin asymmetrical nuclear matter.

Role of Parallel Tempering Monte Carlo Simulation in 2D Ising Spin Glass System with Distance Dependent Interaction

Spin glass system is a complex disordered system with a number of local minima separated by entropic barriers. Therefore, parallel tempering Monte Carlo simulation was used in order to get fast thermalisation （to minimize the relaxation time）. Distance dependent interaction coupling in 2D is studied in order to show how a spin glass phase transition occurs when couplings between far away spins are permitted by considering Edwards-Anderson Ising spin glass model. The interaction coupling is a quenched random variable whose probability of being non-zero decays with distance between two spin sites rij = ｜i-j｜mod（L/2）.The interaction coupling is random and its probability distribution is decaying with the distance between the spins （p（Jij） αrij^-ρ）. The model is studied by changing p among three different regimes （p 〉 2D, 4/3 D〈 p 〈 2D, p 〈 4/3D）. A phase transition temperature for p = 2, 3, 4 is obtained.

Two-component dimers of ultracold atoms with center-of-mass-momentum dependent interactions

In a previous paper[Phys.Rev.A95,060701(R)(2017)],we demonstrated that a new type of two-body interaction,which depends on the center of mass(CoM)momentum,can be realized for ultracold atoms via laser-modulated magnetic Feshbach resonance(MFR).Further studies(e.g.L He et al,Phys.Rev.Lett.120,045302(2018))show that various interesting phenomena,such as Fulde–Ferrell superfluids,can be induced by scattering between ultracold atoms with this interaction.In this work we investigate the shallow bound states of two ultracold atoms with this type of interaction.We show that when the magnetic field B is below the MFR point B0,two shallow bound states can appear in this system.Namely,a'two-component dimer'or a dimer with pseudo-spin 1/2 can be formed by two atoms.Furthermore,the dispersion curve of the dimer may have either single or double minimums in the CoM momentum space.The latter case can be explained as a result from significant pseudo-spin-orbital coupling(SOC)effects.Our results show that the ultracold gases with CoM momentum dependent interaction may be a candidate for quantum simulations with ultracold two-component molecules,especially the molecule gases with SOC.

Effect of thickness on the photophysics and charge carrier kinetics of graphitic carbon nitride nanoflakes

We investigated the thickness effect on the photophysics and charge carrier kinetics of graphitic carbon nitride nanoflakes （g-CNN） by using ultraviolet visible diffuse reflectance spectroscopy, atomic force microscopy, femtosecond transient absorption spectroscopy, and picosecond time-correlated single photon counting measurement. For the first time, we found that g-CNN displays a layer-dependent indirect bandgap and layer-dependent charge carrier kinetics.