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Category: particle physics – Page 707

Are Space, Time, And Gravity All Just Illusions?

Pioneered by Erik Verlinde, the idea is that gravity emerges from a more fundamental phenomenon in the Universe, and that phenomenon is entropy.

“Sound waves emerge from molecular interactions; atoms emerge from quarks, gluons and electrons and the strong and electromagnetic interactions; planetary systems emerge from gravitation in General Relativity. But in the idea of entropic gravity — as well as some other scenarios (like qbits) — gravitation or even space and time themselves might emerge from other entities in a similar fashion. There are well-known, close relationships between the equations that govern thermodynamics and the ones that govern gravitation. It’s known that the laws of thermodynamics emerge from the more fundamental field of statistical mechanics, but is there something out there more fundamental from which gravity emerges? That’s the idea of entropic gravity.”

Entropic gravity, also known as emergent gravity, is a theory in modern physics that describes gravity as an entropic force—a force with macro-scale homogeneity but which is subject to quantum-level disorder—and not a fundamental interaction. The theory, based on string theory, black hole physics, and quantum information theory, describes gravity as an emergent phenomenon that springs from the quantum entanglement of small bits of spacetime information. As such, entropic gravity is said to abide by the second law of thermodynamics under which the entropy of a physical system tends to increase over time.

An Earth-Sized Space Shield to Protect Us From Solar Storms Is Less Crazy Than It Sounds

Every 100 years or so, our Sun gives off a great big belch that sends an intense wave of charged particles towards Earth. This wasn’t a problem in the past, but our high-tech civilization is now disturbingly vulnerable to these solar storms. A new study quantifies the economic risks posed by these extreme solar storms, while also proposing a super-futuristic solution to the problem: an Earth-sized shield built in outer space.

The term “solar storm” is used to identify the various nasties the Sun can hurl our way, including x-rays, charged particles, and magnetized plasma. In 1859, a series of powerful coronal mass ejections (CMEs) hit our planet head on, disrupting telegraph stations and causing widespread communication outages. If we were to be hit by an equally powerful solar storm today, it would knock out satellites and electrical grids, disrupting global communications, transportation, and supply chains. Total worldwide losses could reach up to $10 trillion, with recovery taking many years.

If Atoms Are Mostly Empty Space, Why Do Objects Look And Feel Solid?

Chemist John Dalton proposed the theory that all matter and objects are made up of particles called atoms, and this is still accepted by the scientific community, almost two centuries later. Each of these atoms is each made up of an incredibly small nucleus and even smaller electrons, which move around at quite a distance from the centre. If you imagine a table that is a billion times larger, its atoms would be the size of melons. But even so, the nucleus at the centre would still be far too small to see and so would the electrons as they dance around it. So why don’t our fingers just pass through atoms, and why doesn’t light get through the gaps?

This Quantum Theory Says Time Can Flow Backwards

Quantum physics throws all the rules of classical physics out the window. In the quantum world, particles can pass through solid walls, be in two places at once, and communicate over an infinite distance. And, if a handful of physicists are right, they can affect the past just as easily as they affect the future. That’s a theory known as quantum retrocausality, and researchers have good reasons to believe it’s true.

High-speed quantum memory for photons

Physicists from the University of Basel have developed a memory that can store photons. These quantum particles travel at the speed of light and are thus suitable for high-speed data transfer. The researchers were able to store them in an atomic vapor and read them out again later without altering their quantum mechanical properties too much. This memory technology is simple and fast and it could find application in a future quantum Internet. The journal Physical Review Letters has published the results.

Even today, fast in telecommunication networks employs short light pulses. Ultra broadband technology uses optical fiber links through which information can be transferred at the speed of light. At the receiver’s end, the transmitted information has to be stored quickly and without errors so that it can be processed further electronically on computers. To avoid transmission errors, each bit of information is encoded in relatively strong light pulses that each contain at least several hundreds of photons.

For several years, researchers all over the world have been working on operating such networks with single photons. Encoding one bit per is not only very efficient, but it also allows for a radically new form of information processing based on the laws of physics. These laws allow a single photon to encode not only the states 0 or 1 of a classic bit, but also to encode a superposition of both states at the same time. Such quantum bits are the basis for that could make unconditionally secure communication and super fast quantum computers possible in the future. The ability to store and retrieve single photons from a quantum memory is a key element for these technologies, which is intensively investigated.

How to Store Data on Magnets the Size of a Single Atom

Research and development is focused on developing new means of data storage that are more dense and so can store greater amounts of data, and do so in a more energy efficient way. Sometimes this involves updating established techniques: recently IBM announced a new magnetic tape technology that can store 25 gigabytes per square inch, a new world record for the 60-year-old technology. While current magnetic or solid-state consumer hard drives are more dense at around 200 gigabytes per square inch, magnetic tapes are still frequently used for data back-up.

However, the cutting edge of data storage research is working at the level of individual atoms and molecules, representing the ultimate limit of technological miniaturization.

This New Proof of Majorana Fermions Is Going to Be Massive For Quantum Devices

Quantum computers based on the twisting pathways of moving particles have so far lived only in theory – the particles they would rely on might not even exist.

But with the exciting discovery of electrons ‘swirling’ down a wire, the hunt is over for exactly the particles such quantum devices have been waiting for. Now the work of turning these theoretical computers into reality could soon be underway.

Researchers from the University of Sydney and Microsoft have observed electrons forming a kind of matter called a quasiparticle under conditions that saw them behave as theoretical objects called Majorana fermions.

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