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Deriving measurement collapse using zeta function regularisation and speculative measurement theory 利用泽塔函数正则化和推测测量理论推导测量坍缩
IF 1.2 Q3 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-09-12 DOI: 10.1088/2399-6528/ad6a4c
Mark Stander
This paper shows how an application of zeta function regularisation to a physical model of quantum measurement yields a solution to the problem of wavefunction collapse. Realistic measurement dynamics based on a particle becoming non-isolated are introduced and, based on this, an outcome function is derived using the method of maximum entropy. It is shown how regularisation of an information theoretic quantity related to this outcome function leads to apparent collapse of the wavefunction. The physical principles and key assumptions that underlie this theory are discussed. Some possible experimental approaches are described.
本文展示了如何将 zeta 函数正则化应用于量子测量的物理模型,从而获得波函数坍缩问题的解决方案。本文引入了基于粒子变得非孤立的现实测量动力学,并在此基础上利用最大熵方法推导出了结果函数。研究表明,与该结果函数相关的信息论量的正则化如何导致波函数的明显坍缩。讨论了这一理论的物理原理和关键假设。还介绍了一些可能的实验方法。
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引用次数: 0
Zinc oxide behavior in CO detection as a function of thermal treatment time 氧化锌在一氧化碳检测中的表现与热处理时间的关系
IF 1.2 Q3 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-09-11 DOI: 10.1088/2399-6528/ad777b
M P Munguía-Martín, D Sánchez-Campos, D Mendoza-Anaya, T V K Karthik, L S Villaseñor-Cerón, M I Reyes-Valderrama and V Rodríguez-Lugo
Gas sensors are crucial for safety and well-being in various environments. Zinc oxide (ZnO) gas sensors are notable for their broad gas detection capabilities. In this study, ZnO structures were synthesized by optimized chemical precipitation method with urea, followed by a thermal treatment at 500 °C for 5, 10, 13, and 15 h. The microstructural, morphological, and CO sensing properties were examined. X-ray Diffraction analysis confirmed the hexagonal wurtzite phase. Crystallite size increased from 17.28 to 18.95 nm with longer thermal treatment times. Scanning Electron Microscopy revealed spherical and semi-spherical agglomerates with middle distribution of particle sizes ranging from 140 to 445 nm. The synthesized ZnO structures were evaluated as gas sensors for CO detection. Response time, recovery time, and sensor response were analyzed in a CO atmosphere at 100, 200, and 300 °C. The sample with thermal treatment for 13 h exhibited the lowest Tr of 2.43 s at a concentration of 166 parts per million and 300 °C. The Tr reduction correlated with a ZnO decrease particle size observed with longer thermal treatment times, highlighting the influence of particle size on sensor performance.
气体传感器对于各种环境中的安全和健康至关重要。氧化锌(ZnO)气体传感器因其广泛的气体检测能力而备受瞩目。本研究采用优化的尿素化学沉淀法合成了氧化锌结构,然后在 500 ℃ 下进行了 5、10、13 和 15 小时的热处理。X 射线衍射分析证实了六方晶格相。随着热处理时间的延长,晶体尺寸从 17.28 纳米增加到 18.95 纳米。扫描电子显微镜显示出球形和半球形团聚体,粒径分布在 140 至 445 nm 之间。将合成的氧化锌结构作为检测一氧化碳的气体传感器进行了评估。在 100、200 和 300 °C 的 CO 气氛中分析了响应时间、恢复时间和传感器响应。在浓度为百万分之 166、温度为 300 ℃ 的条件下,经过 13 小时热处理的样品的 Tr 值最低,为 2.43 秒。随着热处理时间的延长,Tr 的降低与 ZnO 粒径的减小有关,这突出表明了粒径对传感器性能的影响。
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引用次数: 0
Teleportation of a qubit using quasi-Bell states 利用准贝尔态实现量子比特的远距传输
IF 1.2 Q3 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-09-08 DOI: 10.1088/2399-6528/ad74c6
Isiaka Aremua and Laure Gouba
In this paper, we study the exotic Landau problem at the classical level where two conserved quantities are derived. At the quantum level, the corresponding quantum operators of the conserved quantities provide two oscillator representations from which we derive two Boson Fock spaces. Using the normalized coherent states which are the minimum uncertainty states on noncommutative configuration space isomorphic to each of the boson Fock space, we form entangled coherent states which are Bell- like states labeled quasi-Bell states. The effect of non-maximality of a quasi-Bell state based quantum channel is investigated in the context of a teleportation of a qubit.
在本文中,我们从经典层面研究了奇异朗道问题,并从中得出了两个守恒量。在量子层面,守恒量的相应量子算子提供了两个振荡器表征,我们从中导出了两个玻色子福克空间。利用归一化相干态(即与每个玻色子 Fock 空间同构的非交换构型空间上的最小不确定态),我们形成了纠缠相干态,这些态类似贝尔态,被标记为准贝尔态。我们以量子比特的远距传输为背景,研究了基于准贝尔态的量子信道的非最大性效应。
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引用次数: 0
The n-shot classical capacity of the quantum erasure channel 量子擦除信道的 n 次经典容量
IF 1.2 Q3 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-08-27 DOI: 10.1088/2399-6528/ad6f6b
Matteo Rosati
We compute the n-shot classical capacity of the quantum erasure channel, providing upper bounds and almost-matching lower bounds for it, the latter achievable via large-minimum-distance classical linear codes for any n. The protocols are in full product form, i.e. no entanglement is needed either at the encoder or decoder to attain the capacity, and they explicitly adapt to the transition between different error regimes as the erasure probability increases. Finally, we show that our upper and lower bounds on the capacity are tighter than those obtainable from the general theory of finite-size capacity via generalized divergences.
我们计算了量子擦除信道的 n 次经典容量,为其提供了上界和几乎匹配的下界,后者可通过任意 n 的大最小距离经典线性编码实现。这些协议是全积形式的,即编码器和解码器都不需要纠缠就能达到容量,而且随着擦除概率的增加,它们能明确地适应不同错误机制之间的转换。最后,我们证明了我们的容量上下限比通过广义发散从有限大小容量的一般理论中获得的容量上下限更严格。
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引用次数: 0
Anisotropic effects in the nondipole relativistic photoionization of hydrogen 氢的非极性相对论光离子化中的各向异性效应
IF 1.2 Q3 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-08-27 DOI: 10.1088/2399-6528/ad6e52
J E Vembe, M Førre
In the nonrelativistic and dipole regime of multiphoton ionization, spherical symmetry in all but the polarization direction of the laser pulse ensures that directional dependency in the photoelectron spectra is limited to the laser polarization direction, with the final distribution exhibiting no asymmetry along the propagation direction of the laser. When relativistic effects and spatial dependency in the external potential are accounted for however, the addition of time dilation and radiation pressure both impose anisotropic effects. Previously we have found that nondipole effects induce a redshift in the photoelectron energy distribution, while conversely relativistic effects induce a blueshift, with the net effect of an apparent near-cancellation of the two. In this work we study these effects further. By examining photoelectron momentum distributions acquired from simulations with the time-dependent Dirac equation we propose explanatory models for both phenomena and present a simplified model of the shifts as a function of the angle relative to the propagation direction of the laser pulse. It is found that both nondipole and relativistic effects must be accounted for on an equal footing in order to correctly describe the photoelectron momentum distribution in the high-intensity regime.
在多光子电离的非相对论和偶极机制中,除了激光脉冲的偏振方向外,其他方向都是球面对称的,这确保了光电子能谱的方向依赖性仅限于激光偏振方向,最终分布沿激光传播方向不呈现不对称。然而,当考虑到相对论效应和外部电势的空间依赖性时,时间膨胀和辐射压力都会产生各向异性效应。在此之前,我们已经发现非偶极子效应会导致光电子能量分布的红移,而相对论效应则会导致蓝移,两者的净效应明显接近抵消。在这项工作中,我们进一步研究了这些效应。通过研究利用随时间变化的狄拉克方程模拟获得的光电子动量分布,我们提出了这两种现象的解释模型,并提出了一个简化的蓝移模型,它是相对于激光脉冲传播方向的角度的函数。我们发现,为了正确描述高强度状态下的光电子动量分布,必须平等地考虑非偶极子效应和相对论效应。
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引用次数: 0
On the mathematical quantification of inequality in probability distributions 论概率分布中不等式的数学量化
IF 1.2 Q3 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-08-14 DOI: 10.1088/2399-6528/ad6ad1
R Rajaram, N Ritchey, B Castellani
A fundamental challenge in the study of probability distributions is the quantification of inequality that is inherently present in them. Some parts of the distribution are more probable and some others are not, and we are interested in the quantification of this inequality through the lens of mathematical diversity, which is a new approach to studying inequality. We offer a theoretical advance, based on case-based entropy and slope of diversity, which addresses inequality for arbitrary probability distributions through the concept of mathematical diversity. Our approach is useful in three important ways: (1) it offers a universal way to measure inequality in arbitrary probability distributions based purely on the entropic uncertainty that is inherent in them and nothing else; (2) it allows us to compare the degree of inequality of arbitrary parts of any distribution (not just tails) and entire distributions alike; and (3) it can glean out empirical rules similar to the 80/20 rule, not just for the power law but for any given distribution or its parts thereof. The techniques shown in this paper demonstrate a more general machinery to quantify inequality, compare the degree of inequality of parts or whole of general distributions, and prove or glean out empirical rules for general distributions based on mathematical diversity. We demonstrate the utility of this new machinery by applying it to the power law, the exponential and the geometric distributions. The 60 − 40 rule of restricted diversity states that 60 percent or more of cases following a power law (or more generally a right skewed distribution) reside within 40 percent or less of the lower bound of Shannon equivalent equi-probable (SEE) types as measured by case-based entropy. In this paper, we prove the 60 − 40 rule for power law distributions analytically. We also show that in all power law distributions, the second half of the distribution is at least 4 times more uniformly distributed as the first. Lastly, we also show a scale-free way of comparing probability distributions based on the idea of mathematical diversity of parts of a distribution. We use this comparison technique to compare the exponential and power law distribution, and obtain the exponential distribution as an entropic limit of the power law distribution. We also demonstrate that the machinery is applicable to discrete distributions by proving a general result regarding the comparison of parts of the geometric distribution.
研究概率分布的一个基本挑战是如何量化分布中固有的不平等现象。分布中的某些部分更有可能出现,而另一些部分则不可能出现,我们有兴趣通过数学多样性的视角来量化这种不平等,这是研究不平等的一种新方法。我们基于基于案例的熵和多样性斜率,提出了一种理论进展,通过数学多样性的概念来解决任意概率分布的不平等问题。我们的方法在三个重要方面非常有用:(1) 它提供了一种通用方法,纯粹基于任意概率分布固有的熵的不确定性,而不是其他;(2) 它允许我们比较任意分布的任意部分(不仅是尾部)和整个分布的不平等程度;(3) 它可以总结出类似于 80/20 规则的经验规则,不仅适用于幂律,而且适用于任何给定的分布或其部分。本文所展示的技术展示了一种更通用的机制,可用于量化不等式、比较一般分布的部分或整体的不等式程度,以及基于数学多样性证明或总结出一般分布的经验规则。我们将这一新机制应用于幂律分布、指数分布和几何分布,以此证明它的实用性。受限多样性的 60 - 40 规则指出,在幂律分布(或更一般的右偏分布)中,60% 或更多的案例位于基于案例熵衡量的香农等效等可能(SEE)类型下限的 40% 或更小范围内。本文通过分析证明了幂律分布的 60 - 40 规则。我们还证明,在所有幂律分布中,后半部分的均匀分布至少是前半部分的 4 倍。最后,我们还展示了一种基于分布各部分数学多样性思想的无标度概率分布比较方法。我们用这种比较技术来比较指数分布和幂律分布,并得出指数分布是幂律分布的熵极限。我们还通过证明有关几何分布各部分比较的一般结果,证明该机制适用于离散分布。
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引用次数: 0
Temperature and medium structurization effect on spontaneous evolution of domains and bubbles in magnetic nanostructures 温度和介质结构化对磁性纳米结构中磁畴和气泡自发演化的影响
IF 1.2 Q3 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-24 DOI: 10.1088/2399-6528/ad61bb
Andrzej Janutka
Spontaneous evolutions of domains in magnetic nanowires and of magnetic bubbles in open ferromagnetic nanolayers are investigated using micromagnetic simulations. We compare temperature dependent dynamics of domain wall (DW) systems in Permalloy (Py) nanowires and systems of chiral DWs in ultra-thin nanowires with perpendicular magnetic anisotropy (PMA) and Dzyaloshinskii-Moriya interaction (DMI). In Py nanowires DWs collide and, in majority of cases, the collision leads to the DW annihilation in disagreement with the expectation of topological protection of sums of all the magnetic charges attached to the nanowire edges which are carried by DWs. For our purpose of discussing the DW collision in the presence of thermal excitations, we revisit the problem of field-driven collisions of DWs in Py nanowires at zero temperature. We claim that thermal fluctuations can counteract the collision-induced annihilation of DWs, thought further improvement of stabilization of domain structures is achievable via structurization of the magnetic nanowires (dividing them into grains). In PMA-DMI nanowires, thermally-excited chiral DWs can be randomly approaching or moving away while not being annihilated. A problem related to the motion of chiral DWs is the spontaneous motion of magnetic bubbles in open PMA-DMI planes. The magnetic bubbles expand or shrink to vanishing dependent on strength of the DMI interaction. Such a motion appears to be be strongly influenced by temperature and by structural discontinuities of the magnetic layer.
我们利用微磁模拟研究了磁性纳米线中磁畴的自发演化和开放式铁磁纳米层中磁泡的自发演化。我们比较了坡莫合金(Py)纳米线中的畴壁(DW)系统和具有垂直磁各向异性(PMA)和 Dzyaloshinskii-Moriya 相互作用(DMI)的超薄纳米线中的手性 DW 系统随温度变化的动力学。在 Py 纳米线中,DW 会发生碰撞,而在大多数情况下,碰撞会导致 DW湮灭,这与 DW 所携带的纳米线边缘所有磁荷之和的拓扑保护预期不符。为了讨论热激发下的 DW 碰撞,我们重新探讨了零温下 Py 纳米线中 DW 的场驱动碰撞问题。我们认为,热波动可以抵消碰撞引起的 DW湮灭,并认为通过磁性纳米线的结构化(将其划分为晶粒)可以进一步提高畴结构的稳定性。在 PMA-DMI 纳米线中,热激发的手性 DW 可以随机靠近或远离,同时不会湮灭。与手性 DW 运动相关的一个问题是开放式 PMA-DMI 平面中磁性气泡的自发运动。磁泡的扩大或缩小到消失取决于 DMI 相互作用的强度。这种运动似乎受到温度和磁层结构不连续性的强烈影响。
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引用次数: 0
Non-unique detailed constructions of Curzon-Ahlborn cycle on thermodynamic plane 热力学平面上 Curzon-Ahlborn 循环的非唯一详细构造
IF 1.2 Q3 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-14 DOI: 10.1088/2399-6528/ad5f0f
Yuki Izumida
The Curzon-Ahlborn (CA) cycle is a paradigmatic model of endoreversible heat engines, which yields the so-called CA efficiency as the efficiency at maximum power. Due to the arbitrariness of the relationship between the steady temperature and the time taken for the isothermal process of the CA cycle, the constructions of the CA cycle on the thermodynamic plane are not unique. Here, we give some of the detailed constructions of the CA cycle on the thermodynamic plane, using an ideal gas as a working substance. It is shown that these constructions are equal to each other in the maximum power regime in the sense that they achieve the best trade-off between the work and the inverse cycle-time, known as the Pareto front in multi-objective optimization problems.
寇尊-阿赫伯恩(CA)循环是一种典型的内可逆热机模型,它产生的所谓 CA 效率是最大功率时的效率。由于 CA 循环的稳定温度与等温过程所需时间之间的关系具有任意性,因此 CA 循环在热力学平面上的构造并不唯一。在此,我们以理想气体为工作物质,给出了热力学平面上 CA 循环的一些详细构造。结果表明,在最大功率条件下,这些结构彼此相等,即它们实现了功与逆循环时间(多目标优化问题中的帕累托前沿)之间的最佳权衡。
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引用次数: 0
Anomalous to normal dispersion nonlinear optical dephasing switch in electromagnetically induced transparency using a Kerr effect 利用克尔效应实现电磁诱导透明中的反常到正常色散非线性光学去相开关
IF 1.2 Q3 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-03 DOI: 10.1088/2399-6528/ad5b39
Ayyappan J and Beena T
The atomic decoherence effect (DE) on a Kerr nonlinear (KNL) electromagnetically induced transparency (EIT)is studied in a Δ system. The DE between the ground state hyperfine levels is caused by the dephasing rate γd which dramatically modifies the medium response. It controls the normal dispersive region which shows steep positive slopes for linear response at the line center while the nonlinear response experiences steep negative slopes for low γd. The microwave field strength and γd modify the nonlinear response from the anomalous dispersion to normal dispersion. The calculations show that room-temperature atoms are used to quantify the quantum interference (QI) on linear and nonlinear absorption with γd. The EIT spectrum explores the understanding of the subluminal and superluminal wave propagation of probe signal and this study opens a new pathway for the understanding of the QI devices and their nonlinearities based on EIT.
在Δ系统中研究了原子退相干效应(DE)对克尔非线性(KNL)电磁诱导透明(EIT)的影响。基态超频水平之间的去相干效应是由去相干率 γd 引起的,它极大地改变了介质响应。它控制着正常色散区域,该区域的线性响应在线心处显示出陡峭的正斜率,而非线性响应在低γd时则显示出陡峭的负斜率。微波场强和 γd 会改变非线性响应,使其从反常色散变为正常色散。计算表明,室温原子可用于量化量子干涉(QI)对γd 的线性和非线性吸收的影响。EIT 光谱探索了对探测信号的亚光速和超光速波传播的理解,这项研究为基于 EIT 理解 QI 器件及其非线性开辟了一条新途径。
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引用次数: 0
Roles of energy and entropy in multiscale dynamics and thermodynamics 能量和熵在多尺度动力学和热力学中的作用
IF 1.2 Q3 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-02 DOI: 10.1088/2399-6528/ad5b3a
Miroslav Grmela
Multiscale thermodynamics is a theory of relations among levels of description. Energy and entropy are its two main ingredients. Their roles in the time evolution describing approach of a level (starting level) to another level involving less details (target level) is examined on several examples, including the level on which macroscopic systems are seen as composed of microscopic particles, mesoscopic levels as kinetic theory of ideal and van der Waals gases, fluid mechanics, the level of chemical kinetics, and the level of equilibrium thermodynamics. The entropy enters the emergence of the target level in two roles. It expresses internal energy, that is the part of the energy that cannot be expressed in terms of the state variables used on the starting level, and it reveals emerging features characterizing the target level by sweeping away unimportant details. In the case when the target level is a mesoscopic level involving time evolution the roles of the energy and the entropy is taken by two different potentials that are related to their rates.
多尺度热力学是一种描述各层次关系的理论。能量和熵是其两个主要成分。在描述从一个层次(起始层次)到另一个涉及较少细节的层次(目标层次)的时间演化过程中,能量和熵的作用在几个例子中进行了研究,包括宏观系统被视为由微观粒子组成的层次、作为理想气体和范德华气体动力学理论的中观层次、流体力学、化学动力学层次以及平衡热力学层次。熵在目标水平的出现中扮演着两种角色。它表示内能,即无法用起始水平上使用的状态变量来表示的那部分能量;它通过扫除不重要的细节来揭示目标水平的新特征。当目标水平是一个涉及时间演化的介观水平时,能量和熵的作用由两个不同的势来承担,这两个势与它们的速率有关。
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引用次数: 0
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