Lifeboat Foundation

Twisting the graphene sheets in a bilayer stack, so that the 2D orientations of the sheets are offset from one another, can drastically affect how the stack reacts to light. Researchers have observed the effect experimentally, but they lack an accurate theory of the behavior. Now Lorenzo Cavicchi at the Scuola Normale Superiore in Italy and collaborators have developed a theory that predicts that light-impinged twisted graphene bilayers could host two kinds of electron oscillations known as plasmons [1]. One of these plasmons, the acoustic plasmon, is tightly confined between the two graphene layers, giving it properties that could allow for its use in studying light–matter interactions.

The electrons in a twisted graphene bilayer are distributed unevenly across the system. This inhomogeneous distribution results from the system’s misaligned carbon atoms. Cavicchi and his colleagues accounted for the electron inhomogeneity in their theory. They also modeled the bilayer as two distinct sheets rather than as a single unit, as was done previously.

The team’s theory predicts the bilayer can host two kinds of plasmon oscillations: the previously known optical plasmon, where all electrons move in the same direction at the same time, and an acoustic plasmon, where the electrons in each sheet move in opposite directions. For a graphene bilayer with a 5° twist angle between the sheets, the researchers predict that the acoustic plasmon should have a velocity of about 840,000 meters per second. That velocity is slow enough that the oscillations are confined within the 0.3-nm gap between the graphene sheets. The researchers say that this tight confinement leads to interactions between the plasmon and incoming light that enhance the intensity of that incoming light. This behavior could be useful for applications in quantum cavities.

New research has established a reversible framework for quantum entanglement, aligning it with the principles of thermodynamics and paving the way for improved manipulation and understanding of quantum resources.

Bartosz Regula from the RIKEN Center for Quantum Computing and Ludovico Lami from the University of Amsterdam have demonstrated through probabilistic calculations the existence of an “entropy” rule for quantum entanglement. This discovery could enhance our understanding of quantum entanglement, a crucial resource underpinning the potential of future quantum computers. Although quantum entanglement has been a research focus in quantum information science for decades, optimal methods for its effective utilization remain largely unknown.

The second law of thermodynamics, which says that a system can never move to a state with lower “entropy”, or order, is one of the most fundamental laws of nature and lies at the very heart of physics. It is what creates the “arrow of time,” and tells us the remarkable fact that the dynamics of general physical systems, even extremely complex ones such as gases or black holes, are encapsulated by a single function, its “entropy.”

Zheng An, Chenfeng Cao, Cheng-Qian Xu, and D. L. Zhou, Quantum 8, 1421 (2024). Identifying phases of matter presents considerable challenges, particularly within the domain of quantum theory, where the complexity of ground states appears to increase exponentially with system size. Quantum many-body systems exhibit an array of complex entanglement structures spanning distinct phases. Although extensive research has explored the relationship between quantum phase transitions and quantum entanglement, establishing a direct, pragmatic connection between them remains a critical challenge. In this work, we present a novel and efficient quantum phase transition classifier, utilizing disentanglement with reinforcement learning-optimized variational quantum circuits. We demonstrate the effectiveness of this method on quantum phase transitions in the transverse field Ising model (TFIM) and the XXZ model. Moreover, we observe the algorithm’s ability to learn the Kramers-Wannier duality pertaining to entanglement structures in the TFIM. Our approach not only identifies phase transitions based on the performance of the disentangling circuits but also exhibits impressive scalability, facilitating its application in larger and more complex quantum systems. This study sheds light on the characterization of quantum phases through the entanglement structures inherent in quantum many-body systems.

Researchers have developed methods to explore and utilize superconductivity in non-equilibrium states, such as those induced by laser pulses, at temperatures much higher than traditional superconductors operate.

This light-induced superconductivity has been shown to replicate crucial features like zero electrical resistance and expulsion of magnetic fields, suggesting potential applications in high-speed devices and extending superconductivity to ambient temperatures.

Superconductivity is a remarkable phenomenon that enables a material to carry an electrical current with zero loss. This collective quantum behavior is unique to certain conductors and only occurs at temperatures significantly below room level.

What is the nature of quantum physics? Neil deGrasse Tyson and comedian Chuck Nice get quantum, exploring Schrodinger’s Cat, electrons, Hilbert Space, and the biggest ideas in the universe (in the smallest particles) with theoretical physicist Sean Carroll.

When did the idea of fields originate? Are fields even real or are they just mathematically convenient? We explore electrons, whether they are a field, and whether they exist at all. We also discuss the wave function, Hilbert Space, and what quantum mechanics really is. Do superpositions always exist?

Continue reading “Neil deGrasse Tyson and Sean Carroll Discuss Controversies in Quantum Mechanics” »

The discovery could radically extend the lifespan and stability of quantum states.

They say that we ultimately lose information once it enters a black hole, but is this really the case? Let’s find out on today’s video. Have you ever wondered what happens to information when it falls into a black hole? Does it get destroyed forever? Does it arrive somewhere else? Does it enter a girl’s bookcase and call it for Murf? Is there a way for it to escape? Today, we’re diving into one of the biggest mysteries in physics: the black hole information paradox. But first, why should we care? Well, in case a black hole suddenly pops up in your bedroom or office table, this paradox sits at the intersection of quantum mechanics and general relativity, the two pillars of modern physics, and solving it could unlock new understandings of the universe itself. So, let’s get started. Our journey begins with looking at the basics of black holes and the paradox that has puzzled scientists for decades.

Like any good explainer, let’s begin with the basics. What exactly is a black hole? In simple terms, a black hole is a region in space where gravity is so strong that nothing, not even light, can escape from it. No Brad, it’s not a challenge; calm down. This happens when a massive star collapses under its own gravity, compressing all its mass into an incredibly small, incredibly dense point known as a singularity. Surrounding the singularity is the event horizon, the boundary beyond which nothing can return. Think of the event horizon as the ultimate point of no return. Once you cross it, you’re inevitably pulled towards the singularity, and there’s no way back. Feel like you know well about black holes? Great. Now let’s talk about Hawking radiation. In the 1970s, Stephen Hawking proposed that black holes aren’t completely black; instead, they emit a type of radiation due to quantum effects near the event horizon. This radiation, aptly named Hawking radiation, suggests that black holes can slowly lose mass and energy over time, eventually evaporating completely. But here’s where things get tricky: Hawking radiation is thermal. By that, we don’t mean that it’s smoking or anything, but that it appears to carry no information about any of the stuff that fell into the black hole. And this brings us to the heart of our mystery: the black hole information paradox. How can the information about the material that formed the black hole and fell into it be preserved if it’s seemingly lost in the radiation? With this foundation in place, I feel that we’re now ready to explore the paradox itself and the various theories proposed to resolve it.
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DISCUSSIONS \& SOCIAL MEDIA

Continue reading “Are Black Holes Cosmic Vaults or Information Gateways?” »

Quantum chromodynamics (QCD) is the theoretical framework for studying the forces within atomic nuclei and their constituent protons and neutrons. A major part of QCD research involves how quarks and gluons are contained within nucleons (protons and neutrons).

Is your mind blown yet? It should be.

We might never reach the stage where we could perform such an experiment, but thinking about it raises several interesting questions. Why is what we believe about how the world works inconsistent with quantum mechanics? Is there an objective reality, even on the macroscopic scale? Or is what you see different than what I see? Do we have a choice in what we do?

At least one thing is for sure: We are not seeing the whole picture. Maybe our understanding of quantum mechanics is incomplete, or maybe something changes when we scale it to the macroscopic world. But perhaps our role as conscious observers of the world around us is, indeed, unique.