Search

In this paper, we consider a special class of one-generator quasi-twisted (QT) codes of index 2 and explore their algebraic structure. By studying the form of Hermitian dual codes, a sufficient condition for self-orthogonality with Hermitian inner product is proposed. Using some one-generator QT codes, we construct some quantum codes on small finite fields. Moreover, a new method is provided to construct maximal-entanglement entanglement-assisted quantum codes via the class of QT codes. By comparison, our quantum codes and maximal-entanglement entanglement-assisted quantum codes have better parameters than any known codes. [ABSTRACT FROM AUTHOR]

Many models with long-range interactions, including the Nagel-Kardar (NK) model, have been proposed to demonstrate and explore the differences between microcanonical ensembles and canonical ensembles. In the NK model, the first-order phase transition always accompanied by the temperature jump in the microcanonical ensemble, while this anomalous temperature jump can not be observed in the canonical ensemble. Moreover, the tricritical points of this model are different from each other in these two different ensembles. In this paper, the microcanonical-canonical crossover behavior of the NK model is studied by placing the NK model in contact with a two-level reservoir, and transition of the tricritical point is presented. [ABSTRACT FROM AUTHOR]

It is well known that quantum codes can be constructed by means of classical symplectic dual-containing codes. This paper considers a family of two-generator quasi-cyclic codes and derives sufficient conditions for these codes to be symplectic dual-containing. Then, a new method for constructing binary quantum codes is proposed. As an application, we construct 8 binary quantum codes that exceed the best-known results. Further, another 36 new binary quantum codes are obtained by propagation rules, all of which improve the lower bound on the minimum distances. [ABSTRACT FROM AUTHOR]