A study on the relations between the topological parameter and entanglement

In this Letter, some relations between the topological parameter d   and concurrences of the projective entangled states have been presented. It is shown that for the case with d=n$d=n$, all the projective entangled states of two n  -dimensional quantum systems are the maximally entangled states (i.e. C=1$C=1$). And for another case with d≠n$d\ne n$, C   both approach 0 when d→+∞$d\to +\infty$ for n=2$n=2$ and 3. Then we study the thermal entanglement and the entanglement sudden death (ESD) for a kind of Yang–Baxter Hamiltonian. It is found that the parameter d   influences not only the critical temperature _Tc$T_c$ but also the maximum entanglement value that the system can arrive at. And we also find that the parameter d has a great influence on the ESD.     

Cross sections for (d–t) neutron interaction with germanium isotopes

The cross sections for (n,x)$(n,x)$ reactions with Ge isotopes were measured at (d–t) neutron energies around 14 MeV with the activation technique using metal discs of natural composition. Calculations of detector efficiency, incident neutron spectrum and correction factors were performed with the Monte Carlo technique (MCNP4C code). Cross sections data are presented for ⁷⁰Ge(n,2n$n,2n$)⁶⁹Ge, ⁷⁴Ge(n,α$n,\alpha$)^71mZn, ⁷⁶Ge(n,2n$n,2n$)^75(m + g)Ge, ⁷⁰Ge(n,p$n,p$)⁷⁰Ga and ⁷²Ge(n,2n$n,2n$)^71gGe reactions. The cross section results for ⁷²Ge(n,2n$n,2n$)^71gGe reaction were reported for the first time. Some other cross sections were obtained with higher precision, including the ⁷⁰Ge(n,p$n,p$)⁷⁰Ga reaction. Theoretical calculations of excitation functions were performed with the TALYS-1.0 code and compared with the experimental cross section values. Data were included in the EXFOR database.     

Pion radiative weak decays in nonlocal chiral quark models

We analyze the radiative pion decay π⁺→e⁺νeγ${\pi }^{+}\to e^{+}{\nu }_e\gamma$ within nonlocal chiral quark models that include wave function renormalization. In this framework we calculate the vector and axial-vector form factors FV$F_V$ and FA$F_A$ at q²=0$q^2=0$ — where q²$q^2$ is the e⁺νe$e^{+}{\nu }_e$ squared invariant mass — and the slope a   of FV(q²)$F_V(q^2)$ at q²→0$q^2\to 0$. The calculations are carried out considering different nonlocal form factors, in particular those taken from lattice QCD evaluations, showing a reasonable agreement with the corresponding experimental data. The comparison of our results with those obtained in the (local) NJL model and the relation of FV$F_V$ and a   with the form factor in π⁰→γ^?γ${\pi }^0\to {\gamma }^{?}\gamma$ decays are discussed.     

Evidence for a spin-quartet of nucleon resonances at 2 GeV

Results from a multichannel partial wave analysis of elastic and inelastic πN and γN   induced reactions are presented. The analysis evidences the existence of a spin-quartet of nucleon resonances with total angular momenta J^P=1/2⁺,…,7/2⁺$J^P=1/2^{+},\dots ,7/2^{+}$. All states fall into a ±130 MeV mass gap centered at 1.97 GeV. The spin quartet is at variance with S-wave diquark configurations required in classical diquark models.     

Twist-three fragmentation function contribution to the single spin asymmetry in pp collisions

We study the twist-three fragmentation function contribution to the single transverse spin asymmetries in inclusive hadron production in pp   collisions, p^↑p→h+X$p^{\uparrow }p\to h+X$. In particular, we calculate the associated derivative terms which dominate the spin asymmetries in these processes. With certain parameterizations for the twist-three fragmentation function, we estimate its contribution to the single spin asymmetry of π⁰${\pi }^0$ production at RHIC energy. We find that the contribution is sizable and might be responsible for the big difference between the asymmetries in η   and π⁰${\pi }^0$ productions observed by the STAR collaboration at RHIC.     

Even-dimensional topological gravity from Chern–Simons gravity

It is shown that the topological action for gravity in 2n  -dimensions can be obtained from the (2n+1)$(2n+1)$-dimensional Chern–Simons gravity genuinely invariant under the Poincaré group. The 2n  -dimensional topological gravity is described by the dynamics of the boundary of a (2n+1)$(2n+1)$-dimensional Chern–Simons gravity theory with suitable boundary conditions.     

Symmetry energy from elliptic flow in Au + Au

The elliptic-flow ratio of neutrons with respect to protons or light complex particles in reactions of neutron-rich systems at relativistic energies is proposed as an observable sensitive to the strength of the symmetry term in the equation of state at supra-normal densities. The results obtained from the existing FOPI/LAND data for ¹⁹⁷Au + ¹⁹⁷Au collisions at 400 MeV/nucleon in comparison with the UrQMD model favor a moderately soft symmetry term with a density dependence of the potential term proportional to γ(ρ/ρ₀)${(\rho /{\rho }_0)}^{\gamma }$ with γ=0.9±0.4$\gamma =0.9\pm 0.4$.     

Odderon and pomeron from the vacuum correlator method

Glueball masses with J?7$J?7$ are computed both for C=+1$C=+1$ and C=−1$C=-1$ using the string Hamiltonian derived in the framework of the vacuum correlator method. No fitting parameters are used, and masses are expressed in terms of string tension σ   and effective value of αs${\alpha }_s$. We extend the calculations done for J?3$J?3$ using the same Hamiltonian, which provided glueball masses in good agreement with existing lattice data, to higher mass states. It is shown that ³⁻⁻,⁵⁻⁻$3^{--},5^{--}$ and ⁷⁻⁻$7^{--}$ states lie on the odderon trajectories with the intercept around or below 0.14. Another odderon trajectory with 3g glueballs of Y-shape, corresponds to 11% higher masses and low intercept. These findings are in agreement with recent experimental data, setting limits on the odderon contribution to the exclusive γp reactions.     

Asymptotic forms for hard and soft edge general β conditional gap probabilities

An infinite log-gas formalism, due to Dyson, and independently Fogler and Shklovskii, is applied to the computation of conditioned gap probabilities at the hard and soft edges of random matrix β-ensembles. The conditioning is that there are n   eigenvalues in the gap, with n?|t|$n?|t|$, t   denoting the end point of the gap. It is found that the entropy term in the formalism must be replaced by a term involving the potential drop to obtain results consist with known asymptotic expansions in the case n=0$n=0$. With this modification made for general n  , the derived expansions — which are for the logarithm of the gap probabilities — are conjectured to be correct up to and including terms O(log|t|)$\mathrm{O}(\log |t|)$. They are shown to satisfy various consistency conditions, including an asymptotic duality formula relating β   to 4/β$4/\beta$.