Robustness of two-qubit and three-qubit states in correlated quantum channels

We investigate how the correlated actions of quantum channels affect the robustness of entangled states. We consider the Bell-like state and random two-qubit pure states in the correlated depolarizing, bit flip, bit-phase flip, and phase flip channels. It is found that the robustness of two-qubit pure states can be noticeably enhanced due to the correlations between consecutive actions of these noisy channels, and the Bell-like state is always the most robust one. We also consider the robustness of three-qubit pure states in correlated noisy channels. For the correlated bit flip and phase flip channels, the result shows that although the most robust and most fragile states are locally unitary equivalent, they exhibit different robustness in different correlated channels, and the effect of channel correlations on them is also significantly different. However, for the correlated depolarizing and bit-phase flip channels, the robustness of two special three-qubit pure states is exactly the same. Moreover, compared with the random three-qubit pure states, they are neither the most robust states nor the most fragile states.     

AdS5\otimes S1, AdS5\otimes S5和AdS2\otimes S2超弦模型的一种KRR参数化新方法

给出了3种典型超弦模型AdS₅\otimes S¹, AdS₅\otimes S⁵和AdS₂\otimes S²的一种简单的KRR参数化新方法, 并结合这些超弦模型所具有的κ对称性给出了它们的卡当1-form, Maurer-Cartan方程, 作用量和运动方程.     

Hamiltonian analysis of a Green-Schwarz sigma model on a supercoset target with Z_（4m） grading

We perform a Hamiltonian analysis of the Green-Schwarz sigma model on a supercoset target with Z_4m grading. The fundamental Poisson brackets between the spatial component of the flat currents depending on a continuous parameter, which can be thought of as a first step in the complete calculation of the algebra of the transition matrices, are obtained. When m=1, our results are reduced to the results of the type IIB Green-Schwarz superstring on AdS₅ × S⁵ background obtained by Das, Melikyan and Sato.     

AdS_5S~1，AdS_5S~5和AdS_2S~2超弦模型的一种KRR参数化新方法

给出了3种典型超弦模型AdS_5(?)S~1,AdS_5(?)S~5和AdS_2(?)S~2的一种简单的KRR参数化新方法,并结合这些超弦模型所具有的κ对称性给出了它们的卡当1-form,Maurer-Cartan方程,作用量和运动方程．     

几种典型背景中Green-Schwarz超弦的κ-对称性

Metsaev和Tseytlin(MT)给出的AdS₅S⁵背景中Green-Schwarz(GS) IIB超弦的Polyakov作用量可以写成等价的Nambu-Goto形式.对于这种形式，给出了新的与靶空间的流有关的投影算子，并用其构造了使作用量不变的局域κ-变换.κ-对称性的这种新方案是由Schwarz对于GS模型提出的.由于MT模型与GS模型有所不同，文中所构造的局域κ-变换有一些新的特点，且适用于其他类似于MT模型的系统.文中分别以AdS₅S¹背景中IIB弦及Polyakov新提出的模型为例，构造了κ-对称性的靶空间形式. 关键词： Green-Schwarz超弦 κ-对称性')" href="#">κ-对称性 AdS₅S⁵')" href="#">AdS₅S⁵ AdS₅S¹')" href="#">AdS₅S¹     

AdS5 (×)S1,AdS5(×)S5和AdS2(×)S2超弦模型的一种KRR参数化新方法

给出了3种典型超弦模型AdS5 (×)S1,AdS5(×)S5和AdS2(×)S2的一种简单的KRR参数化新方法,并结合这些超弦模型所具有的κ对称性给出了它们的卡当1-form,Maurer-Cartan方程,作用量和运动方程.     

几种典型背景中Green-Schwarz超弦的κ-对称性

Metsaev和Tseytlin(MT)给出的AdS5(×)S5背景中Green-Schwarz(GS)IIB超弦的Polakov作用量可以写成等价的Nambu-Goto形式.对于这种形式,给出了新的与靶空间的流有关的投影算子,并用其构造了使作用量不变的局域κ-变换.κ-对称性的这种新方案是由Schwarz对于GS模型提出的.由于MT模型与GS模型有所不同,文中所构造的局域κ-变换有一些新的特点,且适用于其他类似于MT模型的系统.文中分别以AdS5(×)S1背景中IIB弦及Polyakov新提出的模型为例,构造了κ-对称性的靶空间形式.