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"Du, Dong-Hui"
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فهم الصين : السجلات الكاملة للدورة الثانية من المؤتمر الدولي \فهم الصين\
الوقوف على كافة مجريات وتطورات الواقع الصيني فيما يتعلق بسياسات الحزب الشيوعي الصيني بوجه عام، والأوضاع الاقتصادية بالصين على الصعيدين المحلي والدولي، ليس بالأمر الهين على الباحثين والأكاديميين بل والمهتمين بالشأن الصيني عموما، لذا فإن هذا الكتاب \"فهم الصين\" يعد محطة مهمة في قراءة وفهم حاضر الصين ومستقبلها القريب والبعيد على حد سواء، حيث يكتسب هذا الكتاب خصوصيته وأهميته، من كونه يتألف من عدة أوراق بحثية وكلمات لأهم القادة السياسيين الصينيين والدوليين كل من منطلق موقعه السياسي، والذين ألقوا كلماتهم على هامش أهم حدث سياسي يحدث في الصين كل خمس سنوات، وهو اجتماع اللجنة المركزية للحزب الشيوعي الصيني في دورته الثامنة عشرة. ويتناول هذا الكتاب عددا من المحاور الأساسية فيما يتعلق بالسياسة الخارجية للصين، ودورها الاقتصادي إقليميا وعالميا، منها : استراتيجية التنمية الاقتصادية وتعزيز التنمية المنسقة في إطار الخطة الخمسية الثالثة عشرة للصين، وتحسين الحوكمة العالمية وبناء مجتمع المصالح المشتركة على نحو شامل وكذلك المشاركة الفعالة في الحوكمة الاقتصادية العالمية والسعي لتحقيق تنمية سلمية مشتركة، وإدارة الفضاء السيبراني في الصين، بالإضافة إلى استراتيجية الدفاع الوطني الصينية، وتعزيز حماية البيئة الإيكولوجية وبناء مجتمع رغد الحياة بشكل شامل، بالإضافة إلى تحليل وعرض لمستقبل مبادرة \"الحزام والطريق\" في ظل النظام العالمي الجديد.
Book
Island and Page curve for one-sided asymptotically flat black hole
A
bstract
Great breakthrough in solving black hole information paradox took place when semiclassical island rule for entanglement entropy of Hawking radiation was proposed in recent years. Up to now, most papers which discussed island rule of asymptotic flat black hole with
D
≥ 4 focus on eternal black hole. In this paper, we take one more step further by discussing island of “in” vacuum state which describes one-sided asymptotically flat black hole formed by gravitational collapse in
D
≥ 4. We find that island
I
emerges at late time and saves entropy bound. And boundary of island
∂I
depends on the position of cutoff surface. When cutoff surface is far from horizon,
∂I
is inside and near horizon. When cutoff surface is set to be near horizon,
∂I
is outside and near horizon. This is different from the case of eternal black hole in which
∂I
is always outside horizon no matter cutoff surface is far from or near horizon. We will see that different states will manifestly affect
S
ent
in island formula when cutoff surface is far from horizon and thus have different result for Page time.
Journal Article
Bit threads and holographic entanglement of purification
A
bstract
The entanglement of purification (EoP), which measures the classical correlations and entanglement of a given mixed state, has been conjectured to be dual to the area of the minimal cross section of the entanglement wedge in holography. Using the surface-state correspondence, we propose a “bit thread” formulation of the EoP. With this formulation, proofs of some known properties of the EoP are performed. Moreover, we show that the quantum advantage of dense code (QAoDC), which reflects the increase in the rate of classical information transmission through quantum channel due to entanglement, also admits a flow interpretation. In this picture, we can prove the monogamy relation of QAoDC with the EoP for tripartite states. We also derive a new lower bound for
S
(
AB
) in terms of QAoDC, which is tighter than the one given by the Araki-Lieb inequality.
Journal Article
Towards bit threads in general gravitational spacetimes
A
bstract
The concept of the generalized entanglement wedge was recently proposed by Bousso and Penington, which states that any bulk gravitational region
a
possesses an associated generalized entanglement wedge
E
(
a
) ⊃
a
on a static Cauchy surface
M
in general gravitational spacetimes, where
E
(
a
) may contain an entanglement island
I
(
a
). It suggests that the fine-grained entropy for bulk region
a
is given by the generalized entropy
S
gen
(
E
(
a
)). Motivated by this proposal, we extend the quantum bit thread description to general gravitational spacetimes, no longer limited to the AdS spacetime. By utilizing the convex optimization techniques, a dual flow description for the generalized entropy
S
gen
(
E
(
a
)) of a bulk gravitational region
a
is established on the static Cauchy surface
M
, such that
S
gen
(
E
(
a
)) is equal to the maximum flux of any flow that starts from the boundary
∂M
and ends at bulk region
a
, or equivalently, the maximum number of bit threads that connect the boundary
∂M
to the bulk region
a
. In addition, the nesting property of flows is also proved. Thus the basic properties of the entropy for bulk regions, i.e. the monotonicity, subadditivity, Araki-Lieb inequality and strong subadditivity, can be verified from flow perspectives by using properties of flows, such as the nesting property. Moreover, in max thread configurations, we find that there exists some lower bounds on the bulk entanglement entropy of matter fields in the region
E
(
a
) \\
a
, particularly on an entanglement island region
I
(
a
) ⊂ (
E
(
a
) \\
a
), as required by the existence of a nontrivial generalized entanglement wedge. Our quantum bit thread formulation may provide a way to investigate more fine-grained entanglement structures in general spacetimes.
Journal Article
Inequalities of holographic entanglement of purification from bit threads
There are increasing evidences that quantum information theory has come to play a fundamental role in quantum gravity especially the holography. In this paper, we show some new potential connections between holography and quantum information theory. Particularly, by utilizing the multiflow description of the holographic entanglement of purification (HEoP) defined in relative homology, we obtain several new inequalities of HEoP under a max multiflow configuration. Each inequality derived for HEoP has a corresponding inequality of the holographic entanglement entropy (HEE). This is further confirmed by geometric analysis. In addition, we conjecture that, based on flow considerations, each property of HEE that can be derived from bit threads may have a corresponding property for HEoP that can be derived from bit threads defined in relative homology.
Journal Article
Constraints on Hořava–Lifshitz gravity from GRB 170817A
In this work we focus on a toy model: (
3
+
1
)-dimensional Hořava–Lifshitz gravity coupling with an anisotropic electromagnetic (EM) field which is generated through a Kaluza-Klein reduction of a (
4
+
1
)-dimensional Hořava–Lifshitz gravity. This model exhibits a remarkable feature that it has the same velocity for both gravitational and electromagnetic waves. This feature makes it possible to restrict the parameters of the theory from GRB 170817A. In this work we use this feature to discuss possible constraints on the parameter
β
in the theory, by analyzing the possible Lorentz invariance violation effect of the GRB 170817A. This is achieved by analyzing potential time delay of gamma-ray photons in this event. It turns out that it places a stringent constraint on this parameter. In the most ideal case, it gives
|
1
-
β
|
<
(
10
-
19
-
10
-
18
)
.
Journal Article
Improved proof-by-contraction method and relative homologous entropy inequalities
A
bstract
The celebrated holographic entanglement entropy triggered investigations on the connections between quantum information theory and quantum gravity. An important achievement is that we have gained more insights into the quantum states. It allows us to diagnose whether a given quantum state is a holographic state, a state whose bulk dual admits semiclassical geometrical description. The effective tool of this kind of diagnosis is holographic entropy cone (HEC), an entropy space bounded by holographic entropy inequalities allowed by the theory. To fix the HEC and to prove a given holographic entropy inequality, a proof-by-contraction technique has been developed. This method heavily depends on a contraction map
f
, which is very difficult to construct especially for more-region (
n
≥ 4) cases. In this work, we develop a general and effective rule to rule out most of the cases such that
f
can be obtained in a relatively simple way. In addition, we extend the whole framework to relative homologous entropy, a generalization of holographic entanglement entropy that is suitable for characterizing the entanglement of mixed states.
Journal Article
Towards bit threads in general gravitational spacetimes
The concept of the generalized entanglement wedge was recently proposed by Bousso and Penington, which states that any bulk gravitational region \\(a\\) possesses an associated generalized entanglement wedge \\(E(a) a\\) on a static Cauchy surface \\(M\\) in general gravitational spacetimes, where \\(E(a)\\) may contain an entanglement island \\(I(a)\\). It suggests that the fine-grained entropy for bulk region \\(a\\) is given by the generalized entropy \\(S_gen(E(a))\\). Motivated by this proposal, we extend the quantum bit thread description to general gravitational spacetimes, no longer limited to the AdS spacetime. By utilizing the convex optimization techniques, a dual flow description for the generalized entropy \\(S_gen(E(a))\\) of a bulk gravitational region \\(a\\) is established on the static Cauchy surface \\(M\\), such that \\(S_gen(E(a))\\) is equal to the maximum flux of any flow that starts from the boundary \\( M\\) and ends at bulk region \\(a\\), or equivalently, the maximum number of bit threads that connect the boundary \\( M\\) to the bulk region \\(a\\). In addition, the nesting property of flows is also proved. Thus the basic properties of the entropy for bulk regions, i.e. the monotonicity, subadditivity, Araki-Lieb inequality and strong subadditivity, can be verified from flow perspectives by using properties of flows, such as the nesting property. Moreover, in max thread configurations, we find that there exists some lower bounds on the bulk entanglement entropy of matter fields in the region \\(E(a) a\\), particularly on an entanglement island region \\(I(a) (E(a) a)\\), as required by the existence of a nontrivial generalized entanglement wedge. Our quantum bit thread formulation may provide a way to investigate more fine-grained entanglement structures in general spacetimes.
Paper
Improved proof-by-contraction method and relative homologous entropy inequalities
The celebrated holographic entanglement entropy triggered investigations on the connections between quantum information theory and quantum gravity. An important achievement is that we have gained more insights into the quantum states. It allows us to diagnose whether a given quantum state is a holographic state, a state whose bulk dual admits semiclassical geometrical description. The effective tool of this kind of diagnosis is holographic entropy cone (HEC), an entropy space bounded by holographic entropy inequalities allowed by the theory. To fix the HEC and to prove a given holographic entropy inequality, a proof-by-contraction technique has been developed. This method heavily depends on a contraction map \\(f\\), which is very difficult to construct especially for more-region (\\(n\\geq 4\\)) cases. In this work, we develop a general and effective rule to rule out most of the cases such that \\(f\\) can be obtained in a relatively simple way. In addition, we extend the whole framework to relative homologous entropy, a generalization of holographic entanglement entropy that is suitable for characterizing the entanglement of mixed states.
Paper
Island and Page curve for one-sided asymptotically flat black hole
Great breakthrough in solving black hole information paradox took place when semiclassical island rule for entanglement entropy of Hawking radiation was proposed in recent years. Up to now, most papers which discussed island rule of asymptotic flat black hole with \\(D 4\\) focus on eternal black hole. In this paper, we take one more step further by discussing island of \"in\" vacuum state which describes one-sided asymptotically flat black hole formed by gravitational collapse in \\(D 4\\). We find that island \\(I\\) emerges at late time and saves entropy bound. And boundary of island \\( I\\) depends on the position of cutoff surface. When cutoff surface is far from horizon, \\( I\\) is inside and near horizon. When cutoff surface is set to be near horizon, \\( I\\) is outside and near horizon. This is different from the case of eternal black hole in which \\( I\\) is always outside horizon no matter cutoff surface is far from or near horizon. We will see that different states will manifestly affect \\(S_ent\\) in island formula when cutoff surface is far from horizon and thus have different result for Page time.
Paper