Superfluidity of Λ\Lambda hyperons in neutron stars

We study the $^1S_0$ superfluidity of $\Lambda$ hyperons in neutron star matter and neutron stars. We use the relativistic mean field (RMF) theory to calculate the properties of neutron star matter. In the RMF approach, the meson-hyperon couplings are constrained by reasonable hyperon potentials that include the updated information from recent developments in hypernuclear physics. To examine the $^1S_0$ pairing gap of $\Lambda$ hyperons, we employ several $\Lambda\Lambda$ interactions based on the Nijmegen models and used in double-$\Lambda$ hypernuclei studies. It is found that the maximal pairing gap obtained is a few tenths of a MeV. The magnitude and the density region of the pairing gap are dependent on the $\Lambda\Lambda$ interaction and the treatment of neutron star matter. We calculate neutron star properties and find that whether the $^1S_0$ superfluidity of $\Lambda$ hyperons exists in the core of neutron stars mainly depends on the $\Lambda\Lambda$ interaction used.Comment: 22 pages, 2 Tables, 6 Figur

Probing spin entanglement by gate-voltage-controlled interference of current correlation in quantum spin Hall insulators

We propose an entanglement detector composed of two quantum spin Hall insulators and a side gate deposited on one of the edge channels. For an ac gate voltage, the differential noise contributed from the entangled electron pairs exhibits the nontrivial step structures, from which the spin entanglement concurrence can be easily obtained. The possible spin dephasing effects in the quantum spin Hall insulators are also included.Comment: Physics Letters A in pres