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Category: quantum physics – Page 190

A groundbreaking study has demonstrated the use of liquid crystals for efficient and tunable spontaneous parametric down-conversion (SPDC), expanding the potential of quantum light sources beyond traditional solid materials.

Spontaneous parametric down-conversion (SPDC), a key method for generating entangled photons used in quantum physics and technology, has traditionally been restricted to solid materials. However, researchers at the Max Planck Institute for the Science of Light (MPL) and the Jozef Stefan Institute in Ljubljana, Slovenia, have recently achieved a breakthrough by demonstrating SPDC in a liquid crystal for the first time. Their findings, published in Nature, pave the way for the development of a new generation of quantum sources that are both efficient and tunable by electric fields.

The splitting of a single photon in two is one of the most useful tools in quantum photonics. It can create entangled photon pairs, single photons, squeezed light, and even more complicated states of light which are essential for optical quantum technologies. This process is known as spontaneous parametric down-conversion (SPDC).

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Recent research has advanced the development of electron-on-solid-neon qubits, revealing key insights that improve quantum computing by extending qubit coherence times and optimizing their design.

Quantum computers have the potential to be revolutionary tools for their ability to perform calculations that would take classical computers many years to resolve.

But to make an effective quantum computer, you need a reliable quantum bit, or qubit, that can exist in a simultaneous 0 or 1 state for a sufficiently long period, known as its coherence time.

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Conventional encryption methods rely on complex mathematical algorithms and the limits of current computing power. However, with the rise of quantum computers, these methods are becoming increasingly vulnerable, necessitating quantum key distribution (QKD).

QKD is a technology that leverages the unique properties of quantum physics to secure data transmission. This method has been continuously optimized over the years, but establishing large networks has been challenging due to the limitations of existing quantum light sources.

In a new article published in Light: Science & Applications, a team of scientists in Germany have achieved the first intercity QKD experiment with a deterministic single-photon source, revolutionizing how we protect our confidential information from cyber threats.

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Accurate models of real-world scenarios are important for bringing theoretical and experimental research together in meaningful ways. Creating these realistic computer models, however, is a very large undertaking. Significant amounts of data, code, and expertise across a wide range of intricate areas are needed to create useful and comprehensive software.

Dr. Norbert Lütkenhaus, executive director of the Institute for Quantum Computing (IQC) and a professor in the University of Waterloo’s Department of Physics and Astronomy, alongside his research group, have spent the last several years developing accurate software models for research in quantum key distribution (QKD).

QKD is a process for cryptography that harnesses fundamental principles of quantum mechanics to exchange secret keys, which can then be used to ensure secure communication.

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#aliens #robots Welcome to an extraordinary exploration of artificial intelligence and its cosmic counterpart, the astro-chicken! Join me in this mind-blowing video where we delve into the captivating concept of interstellar colonization. You can find my book Gravity: From Falling Apples to Supermassive Black Holes here on Amazon: https://www.amazon.co.uk/Gravity-Fall… The Cosmic Mystery Tour here: https://www.amazon.co.uk/Cosmic-Myste… Artificial intelligences offers the only way to explore the stars. Humans are very delicate and not at all suited to interstellar travel. After all, it is a long long way to the stars. The nearest star is 40 trillion kilometres away. The distance between the stars is too great for it to be feasible to travel so far within human lifespans. The limitations of our biology will prevent us from exploring deep space in person. Although we might like to fantasize about traveling from star system to star system with Captain Kirk, it is almost inconceivable that any humans will ever reach the stars. But maybe there is another way to colonize the galaxy. The British theoretical physicist Freeman Dyson certainly thought so. In the 1960s Dyson, who was one of the architects of quantum electrodynamics — our best theory of electromagnetism — speculated that any sufficiently advanced civilisation would explore the galaxy by launching fleets of autonomous self-replicating robots. There are, of course, many advantages to sending robots rather than humanoids. Robots are more robust than organic lifeforms, they never get bored, and they require far less in the way of maintenance and life support systems. They can survive in harsh environments, and they are adaptable — they can be upgraded. Robots equipped with artificial intelligence could operate autonomously and perform tasks that are impossible for humans, and they could survive indefinitely. Robots could also be miniaturized so they would require far less propulsion to send them on their way. Dyson’s robots would take a blueprint or template that would enable them to create more self-replicating robots. On arrival at a suitable asteroid or planet they would establish a base and set up a means of generating and storing energy. They would then extract and refine minerals and eventually build factories with assembly lines for creating more autonomous robots, each with its own copy of the blueprint, and a propulsion system for the colonization of other star systems. Dyson called these robots astro-chickens. They would travel between the stars as cosmic eggs, hatch on arrival at a suitable destination, then create and disperse the next generation of cosmic eggs. There is no reason, in principle, why super-advanced civilizations could not create such robot explorers. They could attain high speeds as cosmic eggs using some sort of nuclear fusion engine, perhaps. The diameter of our galaxy is about 100,000 light years. Traveling between stars at a significant fraction of the speed of light, the astro-chickens could colonize the entire galaxy in under one million years, which is not long by astronomical or evolutionary time-scales. So where are the astro-chickens? No artefact of an alien civilization has ever been discovered. But, if alien civilizations exist, it might be easier to find their robot descendants than the original aliens. Maybe they are closer than we think. In fact, I have already created my own design for an autonomous, self-replicating robot, which you can witness here on my laptop. Prepare to be enthralled!

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A research team led by Director Jo Moon-Ho of the Center for Van der Waals Quantum Solids within the Institute for Basic Science (IBS) has implemented a novel method to achieve epitaxial growth of 1D metallic materials with a width of less than 1 nm. The group applied this process to develop a new structure for 2D semiconductor logic circuits. Notably, they used the 1D metals as a gate electrode of the ultra-miniaturized transistor.

This research appears in Nature Nanotechnology.

Integrated devices based on two-dimensional (2D) semiconductors, which exhibit excellent properties even at the ultimate limit of material thickness down to the atomic scale, are a major focus of basic and applied research worldwide. However, realizing such ultra-miniaturized transistor devices that can control the electron movement within a few nanometers, let alone developing the manufacturing process for these integrated circuits, has been met with significant technical challenges.

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A research team led by Director JO Moon-Ho of the Center for Van der Waals Quantum Solids within the Institute for Basic Science (IBS) has implemented a novel method to achieve epitaxial growth of 1D metallic materials with a width of less than 1 nanometer (nm). The group applied this process to develop a new structure for 2D semiconductor logic circuits. Notably, they used the 1D metals as a gate electrode of the ultra-miniaturized transistor.

This research was published in the journal Nature Nanotechnology (“Integrated 1D epitaxial mirror twin boundaries for ultra-scaled 2D MoS 2 field-effect transistors”).

Integrated devices based on two-dimensional (2D) semiconductors, which exhibit excellent properties even at the ultimate limit of material thickness down to the atomic scale, are a major focus of basic and applied research worldwide. However, realizing such ultra-miniaturized transistor devices that can control the electron movement within a few nanometers, let alone developing the manufacturing process for these integrated circuits, has been met with significant technical challenges.

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The advent of quantum computers promises to revolutionize computing by solving complex problems exponentially more rapidly than classical computers. However, today’s quantum computers face challenges such as maintaining stability and transporting quantum information.

Phonons, which are quantized vibrations in periodic lattices, offer new ways to improve these systems by enhancing qubit interactions and providing more reliable information conversion. Phonons also facilitate better communication within quantum computers, allowing the interconnection of them in a network.

Nanophononic materials, which are artificial nanostructures with specific phononic properties, will be essential for next-generation quantum networking and . However, designing phononic crystals with desired characteristics at the nano-and micro-scales remains challenging.

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Luminescence refers to the result of a process in which an object absorbs light at one wavelength and then re-emits it at another wavelength. Through light absorption, electrons in the ground state of the material are excited to a higher energy state. After a certain amount of time characteristic of each excited state, the electrons decay to lower energy states, including the ground state, and emit light. The phenomenon is used in a wide array of technological applications involving highly efficient and reproducible emitting devices that can easily be miniaturized.

The materials with the highest luminescence efficiency include (QDs), currently used in high-resolution displays, LEDs, solar panels, and sensors of various kinds, such as those used for precision medical imaging. Functionalization of the surface of QDs with various types of molecules permits interaction with cellular structures or other molecules of interest for the purpose of investigating molecular-level biological processes.

QDs are semiconductor nanoparticles whose emissive characteristics are directly linked to dot size, owing to the phenomenon of quantum confinement. For this reason, monitoring and control of crystal growth during synthesis of QDs in solution permits intelligent planning of the desired luminescence.

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In the Mpemba effect, a warm liquid freezes faster than a cold one. Three studies investigate quantum versions of this effect, challenging our understanding of quantum thermodynamics.

Under certain conditions, warm water can freeze faster than cold water. This phenomenon was named the Mpemba effect after Erasto Mpemba, a Tanzanian high schooler who described the effect in the 1960s [1]. The phenomenon has sparked intense debates for more than two millennia and continues to do so [2]. Similar processes, in which a system relaxes to equilibrium more quickly if it is initially further away from equilibrium, are being intensely explored in the microscopic world. Now three research teams provide distinct perspectives on quantum versions of Mpemba-like effects, emphasizing the impact of strong interparticle correlations, minuscule quantum fluctuations, and initial conditions on these relaxation processes [3– 5]. The teams’ findings advance quantum thermodynamics and have potential implications for technologies, ranging from information processors to engines, powered by quantum resources.

In top-down strategies, physicists use observations of macroscopic (classical) phenomena to infer fundamental microscopic (quantum) processes; in bottom-up strategies, they use studies of those fundamental processes to predict classical phenomena. Historically, studies of the Mpemba effect began with empirical observations and ad hoc assumptions about the microscopic world. Despite descriptions of the effect by Aristotle and Descartes, and modern attention from Mpemba, the phenomenon has not influenced the field of thermodynamics. The Mpemba effect is complex, lacks a precise definition, and has reproducibility issues. As a result, experimental observations and explanations have been debated for decades without consensus, making the effect often seem like just a curiosity.

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