Ratcheting Heat Flux against a Thermal Bias

Merely rocking the temperature in one heat bath can direct a steady heat flux from cold to hot against a non-zero thermal bias in stylized nonlinear lattice junctions that are sandwiched between two heat baths. Likewise, for an average zero-temperature difference between the two contacts a net, ratchet-like heat flux emerges. Computer simulations show that this very heat flux can be controlled and reversed by suitably tailoring the frequency ($\lesssim$ 100 MHz) of the alternating temperature field.Comment: 5 pages, 6 figure

NΩN\Omega and ΔΩ\Delta\Omega dibaryons in SU(3) chiral quark model

The binding energy of the six quark system with strangeness s=-3 is investigated under the chiral SU(3) constituent quark model in the framework of $RGM$. The calculations of the single $N\Omega$ channel with spin S=2 and the single $\Delta\Omega$ channel with spin S=3 are performed. The results show that both systems could be dibaryons and the interaction induced by the chiral field plays a very important role on forming bound states in the systems considered. The phase shifts and scattering lengths in corresponding channels are also given.Comment: LaTex file with 5 figure

Excitation function of nucleon and pion elliptic flow in relativistic heavy-ion collisions

Within a relativistic transport (ART) model for heavy-ion collisions, we show that the recently observed characteristic change from out-of-plane to in-plane elliptic flow of protons in mid-central Au+Au collisions as the incident energy increases is consistent with the calculated results using a stiff nuclear equation of state (K=380 MeV). We have also studied the elliptic flow of pions and the transverse momentum dependence of both the nucleon and pion elliptic flow in order to gain further insight about the collision dynamics.Comment: 8 pages, 2 figure

Dynamic Monte Carlo Study of the Two-Dimensional Quantum XY Model

We present a dynamic Monte Carlo study of the Kosterlitz-Thouless phase transition for the spin-1/2 quantum XY model in two dimensions. The short-time dynamic scaling behaviour is found and the dynamical exponent $\theta$, $z$ and the static exponent $\eta$ are determined at the transition temperature.Comment: 6 pages with 3 figure

τ→ρππν\tau\to\rho\pi\pi\nu decays

Effective chiral theory of mesons is applied to study the four decay modes of $\tau\to\rho\pi\pi\nu$. Theoretical values of the branching ratios are in agreement with the data. The theory predicts that the $a_{1}$ resonance plays a dominant role in these decays. There is no new parameter in this study.Comment: 12 pages and one figur

Elliptic flow in heavy ion collisions near the balance energy

The proton elliptic flow in collisions of Ca on Ca at energies from 30 to 100 MeV/nucleon is studied in an isospin-dependent transport model. With increasing incident energy, the elliptic flow shows a transition from positive to negative flow. Its magnitude depends on both the nuclear equation of state (EOS) and the nucleon-nucleon scattering cross section. Different elliptic flows are obtained for a stiff EOS with free nucleon-nucleon cross sections and a soft EOS with reduced nucleon-nucleon cross sections, although both lead to vanishing in-plane transverse flow at the same balance energy. The study of both in-plane and elliptic flows at intermediate energies thus provides a means to extract simultaneously the information on the nuclear equation of state and the nucleon-nucleon scattering cross section in medium.Comment: 6 pages, 2 figure