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Unraveling the Secrets of Thue-Morse Systems

Explore how Thue-Morse systems reveal insights into particle behavior under various forces.

Vatsana Tiwari, Devendra Singh Bhakuni, Auditya Sharma

― 7 min read


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Table of Contents

Thue-Morse systems are intriguing structures that can help us study various physical laws. They are based on a specific pattern that repeats in a unique way. Imagine a sequence of musical notes that keep playing but switch up the order without losing their rhythm. The Thue-Morse sequence does something like that but with numbers instead.

These systems can be driven by different forces, like Electric Fields, which means we can poke and prod them to see how they react. It is similar to pushing a swing; the way it moves depends on how hard and in what rhythm you push it.

The Basics of Driving Forces

Driving forces are the external influences that affect how a system behaves. In our case, we're looking at how a Thue-Morse system reacts when subjected to periodic (regularly timed) and aperiodic (randomly timed) forces. It's like the difference between someone tapping you on the shoulder at a steady pace versus poking you randomly.

Periodic Driving

Periodic driving means applying a force at regular intervals. When we push a swing steadily, it goes higher and higher until it reaches a point where it doesn't swing back as much. In physics, this helps us identify phases where particles may behave differently, like moving freely or getting stuck.

Aperiodic Driving

Aperiodic driving is more chaotic. The forces push in a less predictable pattern. Think of it like a toddler who randomly decides to jump on the swing. This unpredictability can lead to surprising results. The system may act differently than if it were under steady pressure.

What’s the Big Deal About Localization?

Localization is a fancy term that describes how particles behave in a system. When we talk about "localized" systems, think of it as a bunch of kids at a birthday party who have settled in a corner and won't budge. Conversely, "Delocalized" means the kids are running around everywhere, having a great time.

When we apply these driving forces to a Thue-Morse system, we can see transitions between being localized and delocalized. It's like watching a game of tag; sometimes, the kids huddle together, and other times, they spread out in all directions.

The Electric Field Effect

An electric field is like an invisible force that can push or pull on charged particles, much like how magnets can attract or repel. When we put our Thue-Morse system in an electric field, we are essentially giving it a strong shove to see how it reacts.

This push can cause particles to transition from localized states, where they don't move much, to delocalized states, where they can roam freely. The "localization-to-delocalization transition" is a big deal because it tells us about how energy flows through materials.

Analyzing the Changes

To analyze what happens during these transitions, scientists use different measurements. These include things like how far particles move over time and how the energy in the system changes.

Level Spacing Ratio

The level spacing ratio helps us determine whether a system is behaving more like a local crowd at a party or a group of people going wild on a dance floor. If the spacing looks ordered, it suggests the system is localized. If it seems random, we may be looking at a delocalized system.

Participation Ratio

The participation ratio is like counting how many kids are actually engaged in games versus those who are just hanging around. A higher participation ratio indicates that more particles are actively moving about, suggesting a delocalized state.

Observing the Thue-Morse System

When we turn up the periodic driving, the Thue-Morse system shows fascinating reactions. Think of it like turning up the volume on your favorite song; at first, it’s fun, but eventually, it becomes overwhelming. As the driving increases, particles begin to resist the push, and their behavior starts changing dramatically.

Fractal Dimensions

Fractals are shapes that look the same at any scale, like zooming in on a snowflake. In our context, we can analyze how complex our particle distributions are. A high fractal dimension suggests that particles are spread out in a complicated manner, while a lower dimension indicates they're more concentrated.

When we apply dynamics to the Thue-Morse system, we might find that under specific driving conditions, particles can remain localized even when we expect them to spread out. It’s like watching a group of kids who decided to stay close to the snack table rather than venturing into the wild.

The Role of Statistics

When we explore how particles move, we often rely on statistical methods. These help us make sense of the data we collect. Statistics can paint a clearer picture of how our particles are behaving under various driving conditions. It’s like throwing an annual pizza party and keeping track of how many slices each person eats over the years.

Poisson Statistics

In localized systems, the spacing ratio often aligns with Poisson distribution statistics. This distribution depicts a system where events occur randomly and independently. If particles show this kind of behavior, they are likely localized.

Other Distribution Types

In delocalized systems, we might observe other distribution types that suggest a more mixed behavior. This tells us that something is happening, with particles moving freely and interacting, much like a chaotic dance floor during a party.

The Effect of Disorder

Disorder in a system can refer to irregularities that disrupt the expected arrangement of particles. This could be due to random variations in how particles interact. If the Thue-Morse configuration has too many irregularities, it might resist the push from the driving forces, causing particles to remain localized even under strong external influences.

The Introduction of the Aubry-Andre-Harper Model

The Aubry-Andre-Harper (AAH) model is another fascinating system to consider. It is a standard example of quasiperiodic systems, showcasing a transition from localized to delocalized states as the parameters change. It's like comparing two dance floors: one where everyone’s lively, and the other has a few dancers just swaying to their own beat.

Driving A Long-Range System

When driving a long-range system, the effects are compounded since each particle can influence others over longer distances. This means that even when one particle moves, it can affect many others at once.

Dynamics in the Clean Long-Range System

In a clean long-range Thue-Morse system, applying driving forces tends to create interesting dynamics. The particles can quickly transition between localized and delocalized states, much like a crowd shifting from a calm state to a wild one in a concert.

Dynamics in a Disordered Long-Range System

Disordered systems can be trickier. In these scenarios, applying a driving force may initially appear to cause chaos. However, through some clever tricks—such as adjusting driving parameters—it may still be possible to observe localized states.

As particles slug it out in a disordered environment, they often find themselves in states that blend both behaviors. The interplay of random disorder and periodic driving creates a complex game, with particles occasionally breaking free and running wild while others start to settle down.

Real-World Implications

The study of these systems isn't just academic; it can have real-world consequences. Understanding how particles behave under different forces can help us design better materials for technology, including electronics and energy production.

Practical Applications of Localization

Localization phenomena can yield materials that efficiently conduct electricity or provide insulation, allowing for advancements in solar panels and quantum computing. The search for better materials hinges on our understanding of these transitions and dynamics.

Conclusion: The Future of Thue-Morse Research

The adventure of studying Thue-Morse driven systems is ongoing, with many paths waiting to be explored. As we push the boundaries of knowledge, we may uncover even more secrets about how particles interact under various forces. It’s like being explorers in an uncharted land, eager to see what treasures are hidden beneath the surface.

So, next time you think of pushing that old swing in the backyard, remember: in the world of physics, that simple act could lead to amazing discoveries about how our universe works, one swing at a time!

Original Source

Title: Periodically and aperiodically Thue-Morse driven long-range systems: from dynamical localization to slow dynamics

Abstract: We investigate the electric-field driven power-law random banded matrix(PLRBM) model where a variation in the power-law exponent $\alpha$ yields a delocalization-to-localization phase transition. We examine the periodically driven PLRBM model with the help of the Floquet operator. The level spacing ratio and the generalized participation ratio of the Floquet Hamiltonian reveal a drive-induced fractal phase accompanied by diffusive transport on the delocalized side of the undriven PLRBM model. On the localized side, the time-periodic model remains localized - the average spacing ratio corresponds to Poisson statistics and logarithmic transport is observed in the dynamics. Extending our analysis to the aperiodic Thue-Morse (TM) driven system, we find that the aperiodically driven clean long-range hopping model (clean counterpart of the PLRBM model) exhibits the phenomenon of \textit{exact dynamical localization} (EDL) on tuning the drive-parameters at special points. The disordered time-aperiodic system shows diffusive transport followed by relaxation to the infinite-temperature state on the delocalized side, and a prethermal plateau with subdiffusion on the localized side. Additionally, we compare this with a quasi-periodically driven AAH model that also undergoes a localization-delocalization transition. Unlike the disordered long-range model, it features a prolonged prethermal plateau followed by subdiffusion to the infinite temperature state, even on the delocalized side.

Authors: Vatsana Tiwari, Devendra Singh Bhakuni, Auditya Sharma

Last Update: 2024-12-27 00:00:00

Language: English

Source URL: https://arxiv.org/abs/2412.19736

Source PDF: https://arxiv.org/pdf/2412.19736

Licence: https://creativecommons.org/licenses/by/4.0/

Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.

Thank you to arxiv for use of its open access interoperability.

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