Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: quantum physics

EPFL researchers, with colleagues at the University of Cambridge and IBM Research-Zurich, unravel novel dynamics in the interaction between light and mechanical motion with significant implications for quantum measurements designed to evade the influence of the detector in the notorious ‘back action limit’ problem.

The limits of classical measurements of mechanical motion have been pushed beyond expectations in recent years, e.g. in the first direct observation of , which were manifested as tiny displacements of mirrors in kilometer-scale optical interferometers. On the microscopic scale, atomic- and magnetic-resonance force microscopes can now reveal the atomic structure of materials and even sense the spins of single atoms.

But the that we can achieve using purely conventional means is limited. For example, Heisenberg’s uncertainty principle in implies the presence of “measurement backaction”: the exact knowledge of the location of a particle invariably destroys any knowledge of its momentum, and thus of predicting any of its future locations.

Read more | >

In 1935, physicist Erwin Schrödinger concocted a thought experiment to illustrate a pair of strange quantum physics phenomena: superposition and unpredictability.

The experiment became known as Schrödinger’s cat, and for more than 80 years, it’s served as a cornerstone of quantum physics. But in a newly published study, a team of Yale scientists essentially destroys the premise at the center of the experiment — groundbreaking work that could finally allow researchers to develop useful quantum computers.

Read more | >

Researchers at Nanyang Technological University, Singapore (NTU Singapore) have developed a quantum communication chip that is 1,000 times smaller than current quantum setups, but offers the same superior security quantum technology is known for.

Most leading security standards used in secure communication methods—from withdrawing cash from the ATM to purchasing goods online on the smartphone—does not leverage quantum technology. The electronic transmission of the personal identification number (PIN) or password can be intercepted, posing a .

Roughly three millimeters in size, the tiny chip uses quantum communication algorithms to provide enhanced security compared to existing standards. It does this by integrating passwords within the information that is being delivered, forming a secure quantum key. After the information is received, it is destroyed along with the key, making it an extremely secure form of communication.

Read more | >

Structured light is a fancy way to describe patterns or pictures of light, but deservedly so as it promises future communications that will be both faster and more secure.

Quantum mechanics has come a long way during the past 100 years but still has a long way to go. In AVS Quantum Science, from AIP Publishing, researchers from the University of Witwatersrand in South Africa review the progress being made in using structured light in quantum protocols to create a larger encoding alphabet, stronger security and better resistance to noise.

“What we really want is to do quantum mechanics with patterns of light,” said author Andrew Forbes. “By this, we mean that light comes in a variety of patterns that can be made unique — like our faces.”

Read more | >

A new way to calculate the interaction between a metal and its alloying material could speed the hunt for a new material that combines the hardness of ceramic with the resilience of metal.

The discovery, made by engineers at the University of Michigan, identifies two aspects of this interaction that can accurately predict how a particular alloy will behave—and with fewer demanding, from-scratch quantum mechanical calculations.

“Our findings may enable the use of machine learning algorithms for alloy design, potentially accelerating the search for better alloys that could be used in turbine engines and nuclear reactors,” said Liang Qi, assistant professor of materials science and engineering who led the research.

Read more | >

Researchers at the Kavli Institute for the Physics and Mathematics of the Universe (WPI) and Tohoku University in Japan have recently identified an anomaly in the electromagnetic duality of Maxwell Theory. This anomaly, outlined in a paper published in Physical Review Letters, could play an important role in the consistency of string theory.

The recent study is a collaboration between Yuji Tachikawa and Kazuya Yonekura, two string theorists, and Chang-Tse Hsieh, a condensed matter theorist. Although the study started off as an investigation into string theory, it also has implications for other areas of physics.

In current physics theory, classical electromagnetism is described by Maxwell’s equations, which were first introduced by physicist James Clerk Maxwell around 1865. Objects governed by these equations include electric and magnetic fields, electrically charged particles (e.g., electrons and protons), and magnetic monopoles (i.e. hypothetical particles carrying single magnetic poles).

Read more | >

Hard light computers could be exponential.

Structured light is a fancy way to describe patterns or pictures of light, but deservedly so as it promises future communications that will be both faster and more secure.

Quantum mechanics has come a long way during the past 100 years but still has a long way to go. In AVS Quantum Science researchers from the University of Witwatersrand in South Africa review the progress being made in using structured light in quantum protocols to create a larger encoding alphabet, stronger security and better resistance to noise.

“What we really want is to do quantum mechanics with ,” said author Andrew Forbes. “By this, we mean that light comes in a variety of patterns that can be made unique—like our faces.”

Read more | >

Does quantum computing really exist? It’s fitting that for decades this field has been haunted by the fundamental uncertainty of whether it would, eventually, prove to be a wild goose chase. But Google has collapsed this nagging superposition with research not just demonstrating what’s called “quantum supremacy,” but more importantly showing that this also is only the very beginning of what quantum computers will eventually be capable of.

This is by all indications an important point in computing, but it is also very esoteric and technical in many ways. Consider, however, that in the 60s, the decision to build computers with electronic transistors must have seemed rather an esoteric point as well. Yet that was in a way the catalyst for the entire Information Age.

Most of us were not lucky enough to be involved with that decision or to understand why it was important at the time. We are lucky enough to be here now — but understanding takes a bit of explanation. The best place to start is perhaps with computing and physics pioneers Alan Turing and Richard Feynman.

Read more | >

Have you ever wondered how the Sun creates the energy that we get from it every day and how the other elements besides hydrogen have formed in our universe? Perhaps you know that this is due to fusion reactions where four nuclei of hydrogen join together to produce a helium nucleus. Such nucleosynthesis processes are possible solely due to the existence, in the first place, of stable deuterons, which are made up of a proton and a neutron.

Probing deeper, one finds that a deuteron consists of six light quarks. Interestingly, the strong interaction between quarks, which brings stability to deuterons, also allows for various other six-quark combinations, leading to the possible formation of many other deuteron-like nuclei. However, no such nuclei, though theoretically speculated about and searched for experimentally many times, have yet been observed.

All this may get changed with an exciting new finding, where, using a state-of-the-art first-principles calculation of lattice quantum chromodynamics (QCD), the basic theory of strong interactions, a definite prediction of the existence of other deuteron-like nuclei has been made by TIFR’s physicists. Using the computational facility of the Indian Lattice Gauge Theory Initiative (ILGTI), Prof. Nilmani Mathur and postdoctoral fellow Parikshit Junnarkar in the Department of Theoretical Physics have predicted a set of exotic nuclei, which are not to be found in the Periodic Table. The masses of these new exotic nuclei have also been calculated precisely.

Read more | >