An Invisible Force

A new study reveals that sea squirt oocytes use internal friction to undergo developmental changes post-conception, drawing an interesting parallel to a potter shaping clay. Ascidians, or sea squirts, serve as key models for understanding vertebrate development, sharing similarities with humans. Credit: SciTechDaily.com

Scientists examine how friction forces propel development in a marine organism.

As the potter works the spinning wheel, the friction between their hands and the soft clay helps them shape it into all kinds of forms and creations. 

In a fascinating parallel, sea squirt oocytes (immature egg cells) harness friction within various compartments in their interior to undergo developmental changes after conception. 

A study from the Heisenberg group at the Institute of Science and Technology Austria (ISTA), published in Nature Physics, now describes how this works.  READ MORE...

Measuring a Quantum Paradox

Vacuum chamber containing the atom chip. Credit: Thomas Schweigler, TU Wien

How do quantum particles exchange information? An intriguing hypothesis regarding quantum information has recently been validated through experimental verification conducted at TU Wien.

If you were to randomly pick an individual from a crowd who stands remarkably taller than the average, it’s quite likely that this person will also surpass the average weight. This is because, statistically, knowledge about one variable often gives us some insight into another.

Quantum physics takes these correlations to another level, establishing even more potent connections between disparate quantities: distinct particles or segments of a vast quantum system can “share” a specific amount of information. This intriguing theoretical premise suggests that the calculation of this “mutual information” is surprisingly not influenced by the system’s overall volume, but only by its surface.


This surprising result has been confirmed experimentally at the TU Wien and published in Nature Physics. Theoretical input to the experiment and its interpretation came from the Max-Planck-Institut für Quantenoptik in Garching, FU Berlin, ETH Zürich, and New York University.


“Let’s imagine a gas container in which small particles fly around and behave in a very classical way like small spheres,” says Mohammadamin Tajik of the Vienna Center for Quantum Science and Technology (VCQ) — Atominstitut of TU Wien, first author of the current publication.


“If the system is in equilibrium, then particles in different areas of the container know nothing about each other. One can consider them completely independent of each other. Therefore, one can say that the mutual information these two particles share is zero.”   READ MORE...

Manipulating Quantum LIght

Scientists stand ready to manipulate quantum light, just as Albert Einstein envisioned in 1916.

Researchers from the University of Sydney and the University of Basel successfully managed to manipulate and identify small numbers of interacting photons—packets of light energy. 

According to the team, this work represents an unprecedented landmark development for quantum technologies.

Stimulated light emission—a theory first proposed by Einstein in 1916 that helps explain how photons can trigger atoms to emit other photons—laid the basis for the invention of the laser (Light Amplification by Stimulated Emission of Radiation). 

It’s long been understood for large numbers of photons, but this new research has allowed scientists to both observe and effect stimulated emission for single photons for the first time. Researchers measured the direct time delay between one photon and a pair of bound photons scattering off a single quantum dot, a type of artificially created atom.

“This opens the door to the manipulation of what we can call ‘quantum light,’” Sahand Mahmoodian, of the University of Sydney School of Physics and joint lead author of a research paper published in Nature Physics, says in a news release. 

“This fundamental science opens the pathway for advances in quantum-enhanced measurement techniques and photonic quantum computing.  READ MORE...

Quantum Physics Phenomenon of Materials

Credit: Pixabay/CC0 Public Domain

Researchers at Northeastern have discovered a new quantum phenomenon in a specific class of materials, called antiferromagnetic insulators, that could yield new ways of powering "spintronic" and other technological devices of the future.


The discovery illuminates "how heat flows in a magnetic insulator, [and] how [researchers] can detect that heat flow," says Gregory Fiete, a physics professor at Northeastern and co-author of the research. The novel effects, published in Nature Physics this week and demonstrated experimentally, were observed by combining lanthanum ferrite (LaFeO3) with a layer of platinum or tungsten.

"That layered coupling is what is responsible for the phenomenon," says Arun Bansil, university distinguished professor in the Department of Physics at Northeastern, who also took part in the study.

The discovery may have numerous potential applications, such as improving heat sensors, waste-heat recycling, and other thermoelectric technologies, Bansil says. This phenomenon could even lead to development of a new power source for these—and other—budding technologies. Northeastern graduate student Matt Matzelle and Bernardo Barbiellini, a computational and theoretical physicist at the Lappeenranta University of Technology, who is currently visiting Northeastern, participated in the research.

Illustrating the teams' findings requires considerable magnification (literally) to observe the world of atomic-scale particles—specifically, at the nano-lives of electrons. It also requires an understanding of several properties of electrons—that they possess something called "spin," have a charge, and can, when moving through a material, generate heat flow.

Electron spin, or angular momentum, describes a fundamental property of electrons defined in one of two potential states: Up or down. There are many different ways these "up or down" spins of the electrons (also thought of as north-south poles) orient themselves in space, which in turn gives rise to different types of magnetisms. It all depends, Bansil says, on the ways atoms are patterned in a given material.  READ MORE...

Quantum Physics and Interacting Particles

One of the primary objectives of quantum physics studies is to measure the quantum states of large systems composed of many interacting particles. This could be particularly useful for the development of quantum computers and other quantum information processing devices.

Researchers at the University of Cambridge's Cavendish Laboratory have recently introduced a new approach for measuring the spin states of a nuclear ensemble, a system comprised of many interacting particles with long-lived quantum properties. This method, presented in a paper published in Nature Physics, works by exploiting the response of this system to collective spin excitations.

"For a dense ensemble of quantum objects, such as spins, it isn't possible to measure each individually, to learn how they interacted with each other," Claire Le Gall and Mete Atatüre, two of the researchers who carried out the study, told Phys.org. "Instead, one can look for tell-tale signals in the collective response of the ensemble; a bit like the behavior of a flock of birds might say something about how the birds engage with each other. Our system of interest is a large flock, or ensemble, of nuclear spins in a semiconductor quantum dot."

In 2002, three Harvard University physicists figured out that large ensembles of nuclear spins in a semiconductor quantum dot could be potential hosts for solid-state quantum memories, then published their work a year later. 19 years later, Le Gall, Atatüre, and their colleagues probed this type of nuclear ensemble using a 'proxy' quantum bit, an electron spin that simultaneously couples to all nuclear spins, as reported in their latest paper.  READ MORE...