arXiv subjects

Ming-Qiu Huang

Publications and source records attributed to Ming-Qiu Huang.

60 records · Page 4Linked to original sources

arXiv2002

A Necessary And Sufficient Condition of Distillability with unite fidelity from Finite Copies of a Mixed State: The Most Efficient Purification Protocol

It is well known that any entangled mixed state in $2\otimes 2$ systems can be purified via infinite copies of the mixed state. But can one distill a pure maximally entangled state from finite copies of a mixed state in any bipartite system by local operation and classical communication? This is more meaningful in practical application. We give a necessary and sufficient condition of this distillability. This condition can be expressed as: there exists distillable-subspaces. According to this condition, one can judge whether a mixed state is distillable or not easily. We also analyze some properties of distillable-subspaces, and discuss the most efficient purification protocols. Finally, we discuss the distillable enanglement of two-quibt system for the case of finite copies.

quant-ph↗

arXiv2002

Improved analysis for the baryon masses to order Lambda_{QCD}/m_Q from QCD sum rules

We use the QCD sum rule approach to calculate the masses of the Lambda_Q and Sigma_Q baryons to the Lambda_{QCD}/m_Q order within the framework of heavy quark effective theory. We compare the direct approach and the covariant approach to this problem. Two forms of currents have been adopted in our calculation and their effects on the results are discussed. Numerical results obtained in both direct and covariant approaches are presented. The splitting between spin 1/2 and 3/2 doublets derived from our calculation is {Σ_Q^*}^2-Σ_Q^2\simeq 0.35\pm 0.03 GeV^2 which is in good agreement with the experiment.

hep-ph↗

arXiv2001

Impossibility Criterion for Obtaining Pure Entangled States From Mixed States By Purifying Protocols

Purifying noisy entanglement is a protocol which can increase the entanglement of a mixed state (as a source)at expense of the entanglement of others(as an ancilla)by collective measurement. A protocol with which one can get a pure entangled state from a mixed state is defined as purifying mixed states. We address a basic question: can one get a pure entangled state from a mixed state? We give a necessary and sufficient condition of purifying a mixed state by fit local operations and classical communication and show that for a class of source states and ancilla states in arbitrary bipartite systems purifying mixed states is impossible by finite rounds of purifying protocols. For $2\otimes 2$ systems, it is proved that arbitrary states cannot be purified by individual measurement. The possible application and meaning of the conclusion are discussed.

quant-ph↗

arXiv2001

Reply to Comment

In the comment(quant-ph/0103003) Eggeling,Vollbrecht and Wolf suspect our method in quant-ph/0102133 is not practical. Here we explain our result and method and show that our example can tell one how to judge a separable state, and so our method is practical, at least for many mixed states.

quant-ph↗

arXiv2001

Necessary And Sufficient Condition of Separability of Any System

The necessary and sufficient condition of separability of a mixed state of any systems is presented, which is practical in judging the separability of a mixed state. This paper also presents a method of finding the disentangled decomposition of a separable mixed state.

quant-ph↗

arXiv2000

Leading Isgur-Wise form factor of $Λ_b\toΛ_{c1}$ transition using QCD sum rules

The leading Isgur-Wise form factor $ξ(y)$ parametrizing the semileptonic transitions $Λ_b\toΛ^{1/2}_{c1}\ell\barν$ and $Λ_b\toΛ^{3/2}_{c1}\ell\barν$ is calculated by using the QCD sum rules in the framework of heavy quark effective theory, where $Λ^{1/2}_{c1}$ and $Λ^{3/2}_{c1}$ is the orbitally excited charmed baryon doublet with $J^P=(1^-/2,3^-/2)$. The interpolating currents with transverse covariant derivative are adopted for $Λ^{1/2}_{c1}$ and $Λ^{3/2}_{c1}$ in the analysis. The slope parameter $ρ^2$ in linear approximation of the Isgur-Wise function is obtained to be $ρ^2=2.01$, and the interception to be $ξ(1)=0.29$. The decay branching ratios are estimated.

hep-ph↗