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Category: quantum physics – Page 5

Quantum gravity tests may mistake ordinary spacetime for superposition

Everything around us, from atoms and molecules to planets and galaxies, is governed by two extraordinarily successful theories of physics: quantum mechanics and gravity. Quantum mechanics explains the behavior of the microscopic world, while Einstein’s theory of gravity describes the motion of stars, black holes and the expansion of the universe. Yet despite their successes, physicists are still searching for a theory of “quantum gravity” that would unite them into a single description of nature.

One of the most widely expected features of such a theory is that gravity should obey the laws of quantum mechanics. And this is where it gets difficult: Quantum mechanics predicts that any object can be delocalized over multiple places at once, which is routinely tested in experiments with atoms and even small clumps of metal. Gravity, according to Einstein’s theory, is space and time itself—it can be curved, flat or even have waves propagating through it, as confirmed by gravitational wave detectors. So many physicists believe that spacetime around a quantum object would also exist in multiple “states” simultaneously.

But what would such a situation actually look like?

Tiny magnetic waves could unlock quantum computers the size of a penny

A team of physicists has overcome a major obstacle in quantum computing by dramatically increasing the lifetime of magnons, tiny magnetic waves that can carry quantum information. The researchers extended their lifespan from just a few hundred nanoseconds to as long as 18 microseconds, nearly 100 times longer than previously achieved. The advance could eventually help make ultra-compact quantum computers, potentially as small as a 1-cent coin.

The international research team, led by Andrii Chumak of the University of Vienna, also uncovered an important insight. They found that the lifespan of magnons is not ultimately limited by the laws of physics, but by the quality of the material they travel through. Their findings were published in Science Advances.

Strange Things Are Happening in Quantum Computing

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Quantum computing is supposed to be one of the most exciting new technologies that humanity is working on, with companies promising it can be used in chemistry, material science, logistics, and finance. Over the years, those use cases have been slowly eroded, but investment in quantum tech has only increased. Why? Let’s take a look.

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(PDF) Holographic Entanglement-Weighted de Sitter Gravity

🌌 Holographic theory suggests a profound idea: the universe may store information on its boundary, while the spacetime we experience emerges from that information. In this view, gravity is not only a force between masses.

https://doi.org/10.13140/RG.2.2.17062.

It may also be a macroscopic effect of quantum information, especially entanglement, encoded on a cosmic horizon. 🧠✨

A simple way to express this is:

Horizon information → Entanglement → Spacetime geometry.

To describe how efficiently entanglement becomes geometry, we introduce an entanglement-weight field:

Here, W(x) represents the conversion efficiency from holographic entanglement to gravitational geometry.

This modifies the effective strength of gravity:

Continue reading “(PDF) Holographic Entanglement-Weighted de Sitter Gravity” | >

Microsoft Accelerates Post-Quantum Cryptography Shift to 2029

“Advances in quantum research and development have shifted the risk horizon,” Mark Russinovich, chief technology officer of Microsoft Azure, said. “We believe cryptographically relevant quantum computers could arrive sooner than previously expected – and the work required to prepare is significant, so organizations need to start now.”

To that end, the Windows maker is speeding up the Microsoft Quantum Safe Program (QSP) timeline with the goal of transitioning critical products and services to post-quantum cryptography (PQC) by 2029. The company is also planning to incorporate PQC requirements into its Secure Future Initiative (SFI).

Some key focus areas include upgrading network cryptography by adopting TLS 1.3, building crypto-agility for stored data to facilitate the ability to change cryptography without having to redesign the underlying systems, and transitioning to PQC algorithms to secure trust chains, such as code signing, certificate issuance, key protection, and update pipelines.

Quantum computer simulates hadronization, reproducing string breaking with 104 qubits

By remotely accessing an IBM quantum computer, a research scientist at Lawrence Berkeley National Laboratory has successfully simulated a key process in particle physics: hadronization. Although based on a simplified model of quantum mechanics, the project lays the groundwork for how physicists can leverage the power of quantum computers to make large scientific calculations beyond the capabilities of classical supercomputers. The research is published in the journal Physical Review D.

Hadronization occurs when two or more quarks—the subatomic building blocks of matter—bind together through the strong nuclear force to form composite particles called hadrons. The most familiar examples of hadrons are protons and neutrons, which form the nuclei of atoms. So, having a better understanding of the hadronization process means having a better understanding of the structure of matter, and—in turn—the universe.

Physical experiments have not been able to reveal every step of the process, however. Researchers at the Large Hadron Collider (LHC) at CERN accelerate protons to near light speeds, guide them into collisions and study the resulting debris of quarks and antiquarks. But these particles can only be indirectly measured before they immediately undergo hadronization—hence the need for computer simulations to fill in the gaps of these scientific observations.

Physicists demonstrate Hong–Ou–Mandel interference with more than 10 atoms

In a new study published in Nature Physics, researchers have demonstrated the Hong–Ou–Mandel (HOM) effect with up to 12 indistinguishable neutral atoms—an effect that has been predominantly observed in photonic systems.

The Hong–Ou–Mandel effect is a quantum phenomenon rooted in particle indistinguishability. When two identical bosons meet at a 50:50 beam splitter, they always exit together through the same output port. In other words, they “bunch up.” A single particle at each output is never found, even though that is the statistically expected outcome if the beam splitter were simply distributing particles at random.

First observed with pairs of photons in 1987, the HOM effect has since become central to quantum information and quantum metrology. For two particles, the physics is well established. However, extending it to many particles is a different challenge.

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