Realization Of Dynamics Research Articles

Realization of Hilbert Space Fragmentation and Fracton Dynamics in Two Dimensions

Realization of Hilbert Space Fragmentation and Fracton Dynamics in Two Dimensions

The transformative power of practitioner inquiry: collaborative autoethnography, norm critique and research circles in Swedish education

ABSTRACT This article builds on the social justice and critical and emancipatory dimensions of practitioner inquiry in education. The aim is to demonstrate the potential and challenges of collaborative autoethnography for institutional change, transformative learning and norm critique. Taking Jack Mezirow’s and Paulo Freire’s theoretical framework as a starting point, I analyse four autoethnographic cases conducted by Swedish teachers. I demonstrate the ways in which autoethnography may help teachers realise their own silence and unresponsiveness regarding oppression related to ethnicity, gender, professional role and generational hierarchies in preschools and schools. The collaborative autoethnography also instigates teachers’ realisation of space-time dynamics and other institutionalised constraints and their constitutive power over practices, feelings, understandings and social relations. The transformative learning that has emerged from collaborative autoethnography has led us to recognise the necessity and challenges of conducting empirical analysis, engaging in self-reflection and dialogue, and transforming institutionalised and personal practices and norms. While bringing about institutional change has been challenging, individual and relational transformation has been more achievable. I argue that top-down initiated practitioner inquiry with colleagues and superiors at one’s workplace may be more challenging, and I also argue for the benefits of engaging in practitioner inquiry with people outside one’s own organisation.

Water Sharing Geopolitics between India and Bangladesh: Recent Trends

The partnership between India and Bangladesh according to water sharing is complex by traditional, geographical, political, sociological, and economical issues. Understanding the present dynamics in water-sharing geopolitics is necessary for understanding the pathways of their bilateral partnership and the conjugation for regional sustainability and improvement. Both countries share almost 54 rivers for example Teesta, Ganges, Brahmaputra, and Meghna. These rivers are lifelines for Bangladesh and India, providing essential irrigation water, communication, and indigenous consumption. However, the unequal distribution of water and the influence of climate change have increased challenges over water management procedures. While both countries have contracted diverse treaties and agreements to manage shared rivers, implementation hazards and occasional breaches of trust have channeled their partners. Subsequently, the increasing demand for water due to population enrichment and industrialization shapes modern challenges for stable water mechanisms. This research aims to describe the present dynamics in water-sharing geopolitics between India and Bangladesh, examining the evolving trends, key factors, and their conjugations for regional sustainability and collaboration. By extending the complexities of this critical view of their partnership, this study seeks to contribute to a deeper realization of South Asia's geopolitical arena and prosecutorial dynamics for cooperative water distribution strategies.

Closed-loop designed open-loop control of quantum systems: An error analysis

Quantum Lyapunov control, an important class of quantum control methods, aims at generating converging dynamics guided by Lyapunov-based theoretical tools. However, unlike the case of classical systems, disturbance caused by quantum measurement hinders direct and exact realization of the theoretical feedback dynamics designed with Lyapunov theory. Regarding this issue, the idea of closed-loop designed open-loop control has been mentioned in literature, which means to design the closed-loop dynamics theoretically, simulate the closed-loop system, generate control pulses based on simulation and apply them to the real plant in an open-loop fashion. Based on bilinear quantum control model, we analyze in this article the error, i.e., difference between the theoretical and real systems’ time-evolved states, incurred by the procedures of closed-loop designed open-loop control. It is proved that the error at an arbitrary time converges to a unitary transformation of initialization error as the number of simulation grids between 0 and that time tends to infinity. Moreover, it is found that once the simulation accuracy reaches a certain level, adopting more accurate (thus possibly more expensive) numerical simulation methods does not efficiently improve convergence. We also present an upper bound on the error norm and an example to illustrate our results.

Complete realization of energy landscapes and non-equilibrium trapping dynamics in small spin glass and optimization problems

Energy landscapes are high-dimensional surfaces underlie all physical systems, which determine crucially the energetic and behavioral dependence of the systems on variable configurations, but are difficult to be analyzed due to their high-dimensional nature. Here we introduce an approach to reveal for the complete energy landscapes of spin glasses and Boolean satisfiability problems with a small system size, and unravels their non-equilibrium dynamics at an arbitrary temperature for an arbitrarily long time. Remarkably, our results show that it can be less likely for the system to attain ground states when temperature decreases, due to trapping in individual local minima, which ceases at a different time, leading to multiple abrupt jumps in the ground-state probability. For large systems, we introduce a variant approach to extract partially the energy landscapes and observe both semi-analytically and in simulations similar phenomena. This work introduces new methodology to unravel the energy landscapes and non-equilibrium dynamics of glassy systems, and provides us with a clear, complete and new physical picture on their long-time behaviors inaccessible by existing approaches.

Dynamical analysis and circuit realization of a high complexity fourth-order double-wing chaotic system with transient chaos and its application in image encryption

This paper proposes a fourth-order double-wing chaotic system with high complexity. After conducting a dynamic analysis, it is found that the system exhibits transient chaos and a rare inverse period-doubling bifurcation phenomenon in the bifurcation diagram. The system also exhibits attractor coexistence, with periodic, quasi-periodic, indicating high sensitivity to initial values. These phenomena sufficiently demonstrate the rich dynamical characteristics of chaotic systems. By introducing an impulse function with a cosine function in the foundation of the proposed system, it is found that controllable wing number and staircase burst oscillations occur. Furthermore, the number of wings and oscillation periods vary with changes in parameters, which has significant implications in engineering applications. The circuit design and construction are carried out using the Multisim simulation software, and the digital circuit is realized by using a Field-Programmable Gate Array (FPGA). It is found that the simulation results and the actual implementation results are highly consistent with the phase portrait of the system, thus demonstrating the feasibility of the circuit. Finally, by combining the proposed system with a DNA encryption algorithm, a novel image encryption algorithm with multiple layers of encryption is designed, greatly enhancing the security of encrypted images. The security of this encryption algorithm is analyzed in terms of information entropy, key space, correlation, and resistance to attacks. It is found that the proposed encryption algorithm exhibits high confidentiality and resistance to attacks. The proposed system has significant reference value in secure communication when applied to image encryption.

Symmetry harmonization: exploring deformed oscillators and dissipative dynamics through the glass of Newton–Hooke algebra

Motivated by the symmetry in the non-relativistic limit of anti-de Sitter geometry, we employ planar dynamical models featuring exotic (deformed) harmonic oscillators, presented through direct and indirect Lagrangian representations. The latter introduces Bateman dissipative oscillator system. Analyzing these dynamic systems with a first-order Lagrangian scheme, our phase-space-based approach utilizes the moment map components to reveal the underlying symmetry algebra. This obtained algebra, interpreted as an extended version of Newton–Hooke (NH) cosmological symmetry algebras, has the potential to cast an augmented non-relativistic shadow over the expanding universe, offering an insightful perspective on extended NH spacetime in 2+1 dimensions through our dynamical realizations.

Pricing Indefinitely Lived Assets: Experimental Evidence

We study indefinitely lived assets in experimental markets and find that the traded prices of these assets are on average about 40% of the risk-neutral fundamental value. Neither uncertainty about the value of total dividend payments nor horizon uncertainty about the duration of trade can account for this low traded price. An Epstein-Zin recursive preference specification that models the dynamic realization of dividend payments, combined with either probability weighting or subjects’ heterogeneous risk attitudes, can rationalize the low traded prices observed in our indefinitely lived asset market. This paper was accepted by Yan Chen, behavioral economics and decision analysis. Funding: This work was supported by Concordia University and the Bank of Canada. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2021.03059 .

Reciprocal dynamics in nonlinear systems

Nonreciprocal vibration transmission is an important problem from a fundamental perspective and because of the additional functionalities that it enables in mechanical or acoustic devices. A common realization of nonreciprocal dynamics relies on implementation of nonlinear internal forces within the system. In this talk, we identify and discuss different manifestations of nonreciprocity in nonlinear systems. As a necessary condition, nonreciprocal dynamics is realized in nonlinear systems with broken mirror symmetry. We show that a second symmetry-breaking parameter can counteract the original asymmetry and ultimately restore reciprocal dynamics in a system with broken mirror symmetry, even near the system resonances. Thus, breaking the mirror symmetry is a necessary but insufficient condition for realizing nonreciprocity in nonlinear systems. We also highlight the contribution of phase to nonreciprocal vibration transmission by discussing response regimes that are characterized by nonreciprocal phase shifts. Our findings showcase the potential of asymmetry to serve as an additional design parameter for devices that operate based on nonreciprocity.

Dynamic analysis and circuit realization of a new controllable hyperchaotic system

Amidst the realm of hyper-chaotic systems, a notable deficiency is the absence of amplitude control and signal polarity. This paper addresses this limitation by introducing a new 4-D hyper-chaotic system with a hidden equilibrium-free attractor. The study focuses on amplitude control, achieved by adjusting a specific parameter, enabling manipulation of variable magnitudes while maintaining the overall signal. The offset boosting technique is investigated, enabling flexible shifting of the attractor in a desired direction. A real circuit experiment validates the proposed system’s practical applicability, confirming consistency with theoretical analysis and numerical simulations. Through introducing this new-found, the study holds significant importance for various fields, such as communications engineering and chaos-based cryptography, where precise control of signal characteristics is paramount.

Propagation dynamics of self-accelerating second-order Hermite complex-variable-function Gaussian wave packets in a harmonic potential

This paper investigates the evolutionary dynamics of self-accelerating second-order Hermite complex-variable-function Gaussian (SSHCG) wave packets in a harmonic potential. The periodic variation of the wave packets is discussed via theoretical analysis and numerical simulation. The control variables method is applied to manipulate the distribution factor, cross-phase factor, potential depth, and chirp parameter, enabling the realization of unique propagation dynamics. In three-dimensional models, the SSHCG wave packets exhibit rotational states, featuring butterfly shape, three peaks shape, two polarity shape, elliptical shape, and ring-shaped double-vortex structures. Furthermore, the energy flow and the angular momentum of the wave packets are investigated. Additionally, the performance of the radiation force on a Rayleigh dielectric particle is studied. This investigation results in the emergence of distinct SSHCG wave packet propagation dynamics, and potential applications in optical communications and optical trapping are presented.

4D printing for biomedical applications.

While three-dimensional (3D) printing excels at fabricating static constructs, it fails to emulate the dynamic behavior of native tissues or the temporal programmability desired for medical devices. Four-dimensional (4D) printing is an advanced additive manufacturing technology capable of fabricating constructs that can undergo pre-programmed changes in shape, property, or functionality when exposed to specific stimuli. In this Perspective, we summarize the advances in materials chemistry, 3D printing strategies, and post-printing methodologies that collectively facilitate the realization of temporal dynamics within 4D-printed soft materials (hydrogels, shape-memory polymers, liquid crystalline elastomers), ceramics, and metals. We also discuss and present insights about the diverse biomedical applications of 4D printing, including tissue engineering and regenerative medicine, drug delivery, in vitro models, and medical devices. Finally, we discuss the current challenges and emphasize the importance of an application-driven design approach to enable the clinical translation and widespread adoption of 4D printing.

Realizing impossibilities

It is common in epistemic modal logic to model the epistemic states of agents via box operators in the normal logic S5. However, this approach treats agents as logically omniscient by requiring their knowledge to be closed under classical logical consequence. A promising way of avoiding logical omniscience consists in extending epistemic models with impossible states, that is states, where complex formulas are not evaluated recursively. However, this approach faces the dual problem of logical ignorance by modeling agents as not even minimally logically competent. In this paper I will outline an epistemic logic that combines impossible states with dynamic realization modalities akin to the dynamic announcement operators from public announcement logic (PAL). I will show that this epistemic logic avoids both the problem of logical omniscience and the problem of logical ignorance. Furthermore, I prove that so-called successful updates in my logic can be characterized in the same way as in PAL and that a similar logic due to Johan van Benthem can be simulated in my logic. Finally, I will compare my epistemic logic with a similar one, which has recently been advanced by JC Bjerring and Mattias Skipper.

Dynamical analysis, circuit realization, and applications of 4D hyperchaotic systems with bursty oscillations and infinite attractor coexistence

Dynamical analysis, circuit realization, and applications of 4D hyperchaotic systems with bursty oscillations and infinite attractor coexistence

Realisation of the transient dynamics of dimension-varying control systems

The quotient space method provides a novel idea for modelling the transient dynamics of dimension-varying control systems. This paper investigates the realisation problem of the transient dynamics of dimension-varying control systems. By revealing the structure of the controllable subspace for the linear system on quotient space, we propose the condition for the realisation of the transient dynamics of dimension-varying control systems, based on which a new scheme for modelling the transient dynamics is given. Moreover, the proposed scheme justifies the existing result for the strategy for modelling the transient dynamics. A numeric example is given to illustrate our theoretical results.

Dynamical realization of the small field inflation of Coleman-Weinberg type in the post supercooled universe

The small field inflation (SFI) of Coleman-Weinberg (CW) type suffers from precise tuning of the initial inflaton field value to be away from the true vacuum one. We propose a dynamical trapping mechanism to solve this problem: an ultra-supercooling caused by an almost scale-invariant CW potential traps the inflaton at the false vacuum, far away from the true vacuum dominantly created by the quantum scale anomaly, and allows the inflaton to dynamically start the slow-roll down due to a classical explicit-scale breaking effect. To be concrete, we employ a successful CW-SFI model and show that the proposed mechanism works consistently with the observed bounds on the inflation parameters. The proposed new mechanism thus provides new insights for developing small field inflation models.

Ultrafast control of laser-induced spin-dynamics scenarios on two-dimensional Ni3@C63H54 magnetic system.

The concept of building logically functional networks employing spintronics or magnetic heterostructures is becoming more and more popular today. Incorporating logical segments into a circuit needs physical bonds between the magnetic molecules or clusters involved. In this framework, we systematically study ultrafast laser-induced spin-manipulation scenarios on a closed system of three carbon chains to which three Ni atoms are attached. After the inclusion of spin-orbit coupling and an external magnetic field, different ultrafast spin dynamics scenarios involving spin-flip and long-distance spin-transfer processes are achieved by various appropriately well-tailored time-resolved laser pulses within subpicosecond timescales. We additionally study the various effects of an external magnetic field on spin-flip and spin-transfer processes. Moreover, we obtain spin-dynamics processes induced by a double laser pulse, rather than a single one. We suggest enhancing the spatial addressability of spin-flip and spin-transfer processes. The findings presented in this article will improve our knowledge of the magnetic properties of carbon-based magnetic molecular structures. They also support the relevant experimental realization of spin dynamics and their potential applications in future molecular spintronics devices.

Equilibrium Dynamics of Mutually Confined Waves with Signed Analogous Masses.

We report the first experimental realization of equilibrium dynamics of mutually confined waves with signed analogous masses in an optical fiber. Our Letter is mainly demonstrated by considering a mutual confinement between a soliton pair and a dispersive wave experiencing opposite dispersion. The resulting wave-packet complex is found robust upon random perturbation and collision with other waves. The equilibrium dynamics are also extended to scenarios of more than three waves. Our finding may trigger fundamental interest in the dynamics of many-body systems arising from the concept of negative mass, which is promising for new applications based on localized nonlinear waves.

Aspects of dynamical cobordism in AdS/CFT

The cobordism conjecture implies that consistent theories of Quantum Gravity must admit the introduction of boundaries. We study the dynamical realization of the cobordism conjecture in type IIB in AdS5 × S5, using the existing gravity duals of 4d \U0001d4a9 = 4 SYM with Gaiotto-Witten superconformal boundary conditions (near-horizon limits of D3-branes ending on NS5- and D5-branes). We show that these configurations are, from the 5d perspective, dynamical cobordism solutions which start from an asymptotic AdS5 vacuum and evolve until they hit an end of the world (ETW) brane with AdS4 worldvolume. The latter displays localization of gravity, and provide a completion of the Karch-Randall (KR) AdS branes, in which the backreaction of running scalars replace the KR cusp in the warp factor with a smooth bump. The dynamical scalars are either in the SO(6) invariant AdS5 bulk sector (e.g. describing the S5 size and its shrinking at the cobordism boundary) or brane localized (e.g. the SO(6) SO(3) × SO(3) squashing due to boundary conditions). We introduce a novel double scaling limit which zooms into the ETW brane and makes localization of gravity manifest, and which shows a tantalizing relation with wedge holography. We extend the picture to AdS5 theories with less (super)symmetry, via orbifolds and S-folds, leading to dynamical cobordisms for gravity duals of 4d theories with \U0001d4a9 = 2 and \U0001d4a9 = 3 supersymmetry.

Bragg Solitons – Historical and Future Perspectives

AbstractSolitons have been a subject of intense intellectual curiosity and an avenue for a plethora of applications since they are first observed in water waves. Optical solitons, in particular, have seen tremendous progress, starting from their first theoretical predictions in optical fiber in 1973. On the 50th anniversary of this seminal work from Haseagawa and Tappert, a review is provided on the progress in an important class of optical solitons, the Bragg soliton. Bragg solitons are optical solitons which exist in structures periodic in one dimension. The history of Bragg solitons is described, including the most salient advancements made both in theory and experiments. Recent progress made in integrated photonic devices and their associated design advantages are highlighted, with particular emphasis on how these have facilitated the realization of Bragg soliton dynamics on a chip and their optical processing functions. A discussion and future outlook for this burgeoning field provides a perspective on how Bragg solitons may impact the field of photonics and future applications.