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1. chinaXiv:202202.00008 [pdf]

非互易 Aubry-Andr\'e 模型的经典电路模拟

成恩宏 (Enhong Cheng); 郎利君 (Li-Jun Lang)
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.
Subjects: Physics >> Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology

非厄米的引入扩展了传统厄米量子系统中的概念并诱导出许多新奇的物理现象, 比如非厄米系统所独有的非厄米趋肤效应, 这使得对非厄米量子模型的模拟成为大家关注的热点. 相比于量子平台, 经典系统具有成本低廉、技术成熟、室温条件等优势, 而其中的经典电路系统则更加灵活, 原则上可以模拟任意维度、任意格点间跃迁、任意边界条件下的量子紧束缚模型, 已经成为模拟量子物态的有力平台. 本文利用经典电路通过 SPICE 成功模拟了一个重要的非厄米量子模型 —— 非互易 Aubry-Andr\'e 模型 —— 的稳态性质, 此模型同时具有非互易的格点跃迁和准周期的格点在位势. 以此为例, 详细介绍了如何建立经典电路的拉普拉辛形式与量子紧束缚模型哈密顿矩阵在不同边界条件下的映射, 尤其是如何利用电流型负阻抗变换器构建模型的非互易性. 然后, 根据电路的格林函数, 通过 AC 电流驱动并测量电压响应的方式, 用 SPICE 模拟了周期边界条件下的复能谱和相应的能谱缠绕数, 以及开边界条件下的趋肤与局域模式的竞争. 其中, 为了使电路的响应不发散, 本文还解析地给出辅助元件的设置原则. 结果显示, SPICE 模拟与理论计算很好地吻合, 为进一步的实验实现提供了详细的指导. 由于本文电路设计与测量方案的普适性, 原则上可以直接应用于其他非厄米量子模型的电路模拟. 

submitted time 2022-03-24 Hits2811Downloads434 Comment 0

2. chinaXiv:202203.00008 [pdf]

A Statistical Fields Theory underlying the Thermodynamics of Ricci Flow and Gravity

罗敏杰
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

The paper proposes a statistical fields theory of quantum reference

frame underlying the Perelman's analogies between his formalism of

the Ricci flow and the thermodynamics. The theory is based on a $d=4-\epsilon$

quantum non-linear sigma model (NLSM), interpreted as a quantum reference

frame system which a to-be-studied quantum system is relative to.

The statistic physics and thermodynamics of the quantum frame fields

is studied by the density matrix of them obtained by the Gaussian

approximation quantization. The induced Ricci flow of the frame fields

and the Ricci-DeTurck flow of the frame fields associated with the

density matrix is deduced. In this framework, the diffeomorphism anomaly

of the theory has deep thermodynamic interpretation. The trace anomaly

is related to a Shannon entropy in terms of the density matrix, which

monotonically flows and achieves its maximal value at the flow limit,

called the Gradient Shrinking Ricci Soliton (GSRS). A relative Shannon

entropy w.r.t. the maximal entropy gives a statistical interpretation

to Perelman's partition function, which is also monotonic and giving

an analogous H-theorem to the statistical frame fields system. We

find that a temporal static 3-space of the GSRS spacetime is in a

thermal equilibrium state, and Perelman's analogies between his formalism

and the thermodynamics of the frame fields in equilibrium can be explicitly

given in the framework. As a possible underlying microscopic theory

of the gravitational system, the theory is also applied to understand

the thermodynamics of the Schwarzschild black hole. The cosmological

constant in the effective theory of gravity at cosmic scale is also

briefly given.

submitted time 2022-03-03 Hits2432Downloads474 Comment 0

3. chinaXiv:202201.00098 [pdf]

新疆草地生态系统健康评价体系构建

陈春波
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

草地是重要的陆地生态系统类型,草地生态系统健康评价是干旱区草地健康研究的重要组成部分。新疆位于中亚干旱区,典型的“山盆”地形结构孕育的天然草地具有鲜明的垂直地带性,又因水热组合差异形成了丰富多样的草地类型,这使得新疆草地生态系统健康评价成为一项系统的复杂工作,急需构建适用于新疆的草地生态系统健康评价体系。本研究以新疆草地生态系统为研究对象,构建新疆草地生态系统健康评价总体框架,从数据来源与评价方法阐述了新疆草地生态系统健康评价体系。基于草地样方、生物气象与多源遥感数据建立草地生态系统基础数据库,针对草地健康评价方法,明确评价目标,确定评价区域与参照系统,进而筛选评价指标,最后通过选择评价方法开展草地健康评价,采用四分法将评价结果划分为健康、亚健康、警戒与崩溃。采用该体系在新疆和田地区民丰县开展草地生态系统健康评价,结果显示围栏内的温性荒漠类草地处于健康状态,围栏外的温性荒漠类草地为亚健康状态。通过构建新疆草地生态系统健康评价体系,能够为基层草原部门开展草地生态健康评价提供参考,促进草地可持续发展。

submitted time 2022-01-26 Cooperative journals:《干旱区研究》 Hits2462Downloads310 Comment 0

4. chinaXiv:202112.00082 [pdf]

博斯腾湖小湖区湿地生态需水量阈值研究

刘英
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

湿地生态需水量阈值是其生态系统发生质变的临界条件,一旦某阈值被超越,系统的某些 物质平衡关系、功能、健康就会受到影响,而月尺度的湿地生态需水量阈值研究有助于水资源优化 配置。针对博斯腾湖小湖区芦苇沼泽镶嵌交错明水塘道的景观结构,结合遥感数据同步获取大范 围数据的优势,利用长时间序列的水面面积频率分析,确定月尺度最小、中等和理想状态的小湖区 湿地明水区面积;采用蒸发皿观测值计算法,核算小湖区湿地的月尺度最小、中等和理想生态耗水量。结果表明:小湖区湿地全年月平均最小、中等和理想的生态水面面积为 14.47 km2、21.56 km2、 26.75 km2;小湖区湿地生长季 3—9 月最小生态需水量为 0.22×108 m3、0.35×108 m3、0.44×108 m3、0.51×108 m3、0.39×108 m3、0.41×108 m3、0.28×108 m3,其中 6 月最大,3 月最小,小湖区湿地年最小生态 需水量约为 3.02×108 m3;如若同时满足小湖区湿地生态目标芦苇生长所需动态水位,3—9 月最小 生态需水量为 0.40×108 m3、0.52×108 m3、0.79×108 m3、0.86×108 m3、2.31×108 m3、0.41×108 m3、0.28×108 m3,其中 7 月最大,9 月最小,小湖区湿地年最小生态需水量约为 5.99×108 m3。本研究计算结果可用于小湖区湿地年、月尺度来水分配及出水调控,有利于提高区域水资源利用效率,确保小湖生态可持续发展。

submitted time 2021-12-14 Cooperative journals:《干旱区地理》 Hits5028Downloads326 Comment 0

5. chinaXiv:202112.00084 [pdf]

THz permeability of FePt nanowire

Han, Mangui; Meng, Sen
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

与单根Fe纳米线的GHz磁导率相比较,我们对具有L10型晶体结构的FePt纳米线在处于剩余磁化状态下(Mr/Ms=1.0)的太赫兹磁导率进行了微磁学仿真。由于FePt纳米线具有很强的磁晶各向异性场,我们的研究表明它可以在0.348THz下具有很强的太赫兹磁导率,这曾被认为只能通过人工超材料才能获得。L10-FePt纳米线的THz磁谱明显不同于Fe纳米线GHz下的磁谱,它存在不同寻常的负数磁导率虚部(u"<0),我们认为这与它不寻常自然共振下的旋进过程所导致的等效负数阻尼系数相关。

submitted time 2021-12-14 Hits5877Downloads481 Comment 0

6. chinaXiv:202110.00018 [pdf]

纠缠与量子力学中测量问题的“多时空”方案

胡锦文
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

探讨了量子力学诠释中的哥本哈根解释以及“多世界”量子诠释,发现它们间可以有一种折中方案,即“多时空”方案,该方案认为,宇宙中时空可能并不是唯一的,任何系统间的相互作用都会形成一个独立的时空。这些系统在该时空中表现为“粒子”属性,而在其它无关的时空“看来”,这些系统则表现为“波动”属性。在“多时空”方案中,观察者的角色不必如哥本哈根解释中至关重要,而是被沦为了普通地位。同时论证了“多时空”方案下测量的客观性问题。“多时空”方案给量子力学中的测量问题提供了一个新的理解,但是它并未与当前的物理试验有所冲突,仍然居于量子力学的框架之内。

submitted time 2021-10-10 Hits5386Downloads464 Comment 0

7. chinaXiv:202108.00098 [pdf]

On the Generalized Uncertainty Principle

Ming-Cheng Chen; Chao-Yang Lu; Jian-Wei Pan
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Generalized Uncertainty Principle (GUP), which manifests a minimal Planck length in quantum spacetime, is central in various quantum gravity theories and has been widely used to describe the Planck-scale phenomenon. Here, we propose a thought experiment based on GUP – as a quantum version of Galileo's falling bodies experiment – to show that the experimental results cannot be consistently described in quantum mechanics. This paradox arises from the interaction of two quantum systems in an interferometer, a photon and a mirror, with different effective Planck constants. Our thought experiment rules out the widely used GUP, and establishes a Quantum Coupling Principle that two physical systems of different effective Planck constants cannot be consistently coupled in quantum mechanics. Our results point new directions to quantum gravity.

submitted time 2021-08-13 Hits7663Downloads632 Comment 0

8. chinaXiv:202106.00104 [pdf]

自对偶地图上伊辛模型的相变临界点

张孝伍
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

给定连通地图M=(V,E,F) ,在每个节点v 处赋于一个自旋,每条边上的两个节点有相互作用, 得到地图M 上的伊辛模型.由伊辛模型的对偶变换,给出了自对偶地图上伊辛模型相变临界点K* 的上下界:0.2406≤K*≤0.7218 ,并且得到三维自对偶伊辛模型的相变临界点:K*=0.5269

submitted time 2021-06-22 Hits7915Downloads604 Comment 0

9. chinaXiv:202105.00063 [pdf]

本源司南:高效利用量子资源的量子操作系统

孔伟成; 王俊超; 韩永健; 吴玉椿; 张 昱; 窦猛汉; 方 圆; 郭国平
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

随着超导等量子处理器技术的不断进步,高效利用量子处理器、实现量子计算机与经典计算平台的有效协作,已成为量子计算实用化发展的迫切需求。本源司南就是一种面向此需求的量子操作系统,它提供量子任务调度、量子资源管理、量子程序编译、量子比特自动化校准等服务,统一、高效地管理量子计算资源。本文提出用于本源司南的多量子处理器负载均衡、基于量子线路映射的多量子程序并行计算、基于隐式马尔科夫链的量子比特自动化校准等技术方案,通过将本源悟源等量子计算平台接入本源司南前后的数据对比:在测试4种代表性的量子线路(QFT,GHZ,DJ,BV)实验中相较于BMT算法的映射效果,经过本源司南映射后线路的保真度至少提高10%;在运行GHZ量子线路实验中,本源司南提供的单量子处理器并行计算与多量子处理器负载均衡计算能力使量子处理器的运行效率至少提高120%。本源司南能协同调度量子处理器(QPU)、经典计算机等计算资源,为量子计算的广泛使用提供了有效的资源管理。

submitted time 2021-05-17 Hits12006Downloads1475 Comment 0

10. chinaXiv:202103.00135 [pdf]

New ordinal relative fuzzy entropy

Yuanpeng He
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

In real life, occurrences of a series of things are supposed to come in an order. Therefore, it is necessary to regard sequence as a crucial factor in managing different kinds of things in fuzzy environment. However, few related researches have been made to provided a reasonable solution to this demand. Therefore, how to measure degree of uncertainty of ordinal fuzzy sets is still an open issue. To address this issue, a novel ordinal relative fuzzy entropy is proposed in this paper taking orders of propositions into consideration in measuring level of uncertainty in fuzzy environment. Compared with previously proposed entropies, effects on degrees of fuzzy uncertainty brought by sequences of sequential propositions are embodied in values of measurement using proposed method in this article. Moreover, some numerical examples are offered to verify the correctness and validity of the proposed entropy.

submitted time 2021-03-23 Hits12153Downloads956 Comment 0

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