Equilibrium thermodynamic properties of binary hard-sphere mixtures from integral equation theory

We present an equilibrium thermodynamic properties of binary hard-sphere mixtures from integral equation approach combined with the Percus-Yevick (PY) and the Martynov-Sarkisov (MS) approximations. We use the virial, the compressibility and the Boubl\'{i}k-Mansoori-Carnahan-Starling-Leland (BMCSL) equations of state in the PY approximation, while the virial equation of state is only employed in the MS approximation. We employ a closed-form expression for evaluating the excess chemical potential. The excess Helmholtz free energy is obtained using the Euler relation of thermodynamics. For a number of binary sets of the mixtures we compare our findings for thermodynamic properties with previously obtained results in the literature. Generally, the findings from the MS approximation show better agreement with the results than those from the PY approximation.Comment: 10 pages, 6 figure

Pressure consistency for binary hard-sphere mixtures from an integral equation approach

The site-site Ornstein-Zernike equation combined with the Verlet-modified bridge function has been applied to the binary hard sphere mixtures and pressure consistency has been tested. An equation of state has been computed for the case where a packing fraction is $\eta = 0.49$, diameter ratios are $\sigma_{2}/\sigma_{1} = 0.3$ and $0.6$, and the mole fractions are $x_{1} = 0.125, 0.5, 0.75$, and $1$. An excess chemical potential for each component has been obtained as well. Our findings for thermodynamic properties are in good agreement with available data in literature.Comment: 9 page

Numerical solution to the time-dependent Gross-Pitaevskii equation

We solve the time-dependent Gross-Pitaevskii equation modeling the dynamics of the Bose-Einstein condensate trapped in one-dimensional and two-dimensional harmonic potentials using the split-step technique combined with a pseudospectral representation. We apply this method to the simulation of condensate breathing when an inter-particle interaction in the system is not too strong.Comment: 11 pages, 8 figure

Calculation of the entropy for hard-sphere from integral equation method

The Ornstein-Zernike integral equation method has been employed for a single-component hard sphere fluid in terms of the Percus-Yevick (PY) and Martynov-Sarkisov (MS) approximations. Virial equation of state has been computed in both approximations. An excess chemical potential has been calculated with an analytical expression based on correlation functions, and the entropy has been computed with a thermodynamic relation. Calculations have been carried out for a reduced densities of 0.1 to 0.9. It has been shown that the MS approximation gives better values than those from the PY approximation, especially for high densities and presents a reasonable comparison with available data in the literature.Comment: 7 page

Evidence of a resonant structure in the e+e−→π+D0D∗−e^+e^-\to \pi^+D^0D^{*-} cross section between 4.05 and 4.60 GeV

The cross section of the process e+e-→π+D0D*- for center-of-mass energies from 4.05 to 4.60 GeV is measured precisely using data samples collected with the BESIII detector operating at the BEPCII storage ring. Two enhancements are clearly visible in the cross section around 4.23 and 4.40 GeV. Using several models to describe the dressed cross section yields stable parameters for the first enhancement, which has a mass of 4228.6±4.1±6.3  MeV/c2 and a width of 77.0±6.8±6.3  MeV, where the first uncertainties are statistical and the second ones are systematic. Our resonant mass is consistent with previous observations of the Y(4220) state and the theoretical prediction of a DD¯1(2420) molecule. This result is the first observation of Y(4220) associated with an open-charm final state. Fits with three resonance functions with additional Y(4260), Y(4320), Y(4360), ψ(4415), or a new resonance do not show significant contributions from either of these resonances. The second enhancement is not from a single known resonance. It could contain contributions from ψ(4415) and other resonances, and a detailed amplitude analysis is required to better understand this enhancement