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Japanese and U.S. physicists have used atoms about 3 billion times colder than interstellar space to open a portal to an unexplored realm of quantum magnetism.

“Unless an alien civilization is doing experiments like these right now, anytime this experiment is running at Kyoto University it is making the coldest fermions in the universe,” said Rice University’s Kaden Hazzard, corresponding theory author of a study published today in Nature Physics. “Fermions are not rare particles. They include things like electrons and are one of two types of particles that all matter is made of.”

A Kyoto team led by study author Yoshiro Takahashi used lasers to cool its fermions, atoms of ytterbium, within about one-billionth of a degree of absolute zero, the unattainable temperature where all motion stops. That’s about 3 billion times colder than interstellar space, which is still warmed by the afterglow from the Big Bang.

Atoms in magnetic materials are organized into regions called magnetic domains. Within each domain, the electrons have the same magnetic orientation. This means their spins point in the same direction. “Walls” separate the magnetic domains. One type of wall has spin rotations that are left-or right-handed, known as having chirality. When subjected to a magnetic field, chiral domain walls approach one another, shrinking the magnetic domains.

Researchers have developed a magnetic material whose thickness determines whether chiral domain walls have the same or alternating handedness. In the latter case, applying a magnetic field leads to annihilation of colliding domain walls. The researchers combined neutron scattering and electron microscopy to characterize these internal, microscopic features, leading to better understanding of the magnetic behavior.

An emerging field of technology called spintronics involves processing and storing information by harnessing an electron’s spin instead of its charge. The ability to control this fundamental property could unlock new possibilities for developing electronic devices. Compared to current technology, these devices could store more information in less space and operate at higher speeds with less energy consumption.

Researchers have discovered a new method for correcting errors in the calculations of quantum computers, potentially clearing a major obstacle to a powerful new realm of computing.

In conventional computers, fixing errors is a well-developed field. Every cellphone requires checks and fixes to send and receive data over messy airwaves. Quantum computers offer enormous potential to solve certain complex problems that are impossible for conventional computers, but this power depends on harnessing extremely fleeting behaviors of subatomic particles. These computing behaviors are so ephemeral that even looking in on them to check for errors can cause the whole system to collapse.

In a paper outlining a new theory for error correction, published Aug. 9 in Nature Communications, an interdisciplinary team led by Jeff Thompson, an associate professor of electrical and computer engineering at Princeton, and collaborators Yue Wu and Shruti Puri at Yale University and Shimon Kolkowitz at the University of Wisconsin-Madison, showed that they could dramatically improve a quantum computer’s tolerance for faults, and reduce the amount of redundant information needed to isolate and fix errors. The new technique increases the acceptable error rate four-fold, from 1% to 4%, which is practical for quantum computers currently in development.

Composite particles with submicron sizes can be produced by irradiating a suspension of nanoparticles with a laser beam. Violent physical and chemical processes take place during irradiation, many of which have been poorly understood to date. Recently completed experiments, carried out at the Institute of Nuclear Physics of the Polish Academy of Sciences in Cracow, have shed new light on some of these puzzles.

When a laser beam strikes agglomerates of nanoparticles suspended in a colloid, events occur that are as dramatic as they are useful. The tremendous increase in temperature leads to the melting together of nanoparticles into a composite particle. A thin layer of liquid next to the heated material rapidly transforms into vapor, and whole sequences of chemical reactions take place under physical conditions that change in fractions of a second. Using this method, called laser melting, scientists from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Cracow not only produced new nanocomposites, but also described some of the poorly understood processes responsible for their formation.

“The laser melting process itself, consisting of irradiating particles of material in suspension with unfocused laser light, has been known for years. It is mainly used for the production of single component materials. We, as one of only two research teams in the world, are trying to use this technique to produce composite submicron particles. In this area, the field is still in its infancy, there are still many unknowns, hence our joy that some puzzles that perplexed us have just been unraveled,” says Dr. Żaneta Świątkowska-Warkocka, a professor at IFJ PAN, the co-author of a scientific article just published in the journal Scientific Reports.

Nuclear physicists studying particle collisions at the Relativistic Heavy Ion Collider (RHIC)—a U.S. Department of Energy Office of Science user facility at DOE’s Brookhaven National Laboratory—have new evidence that particles called gluons reach a steady “saturated” state inside the speeding ions. The evidence is suppression of back-to-back pairs of particles emerging from collisions between protons and heavier ions (the nuclei of atoms), as tracked by RHIC’s STAR detector. In a paper just published in Physical Review Letters, the STAR collaboration shows that the bigger the nucleus the proton collides with, the larger the suppression in this key signature, as predicted by theoretical models of gluon saturation.

“We varied the species of the colliding ion beam because theorists predicted that this sign of saturation would be easier to observe in heavier nuclei,” explained Brookhaven Lab physicist Xiaoxuan Chu, a member of the STAR collaboration who led the analysis. “The good thing is RHIC, the world’s most flexible collider, can accelerate different species of ion beams. In our analysis, we used collisions of protons with other protons, aluminum, and gold.”

Saturation should be easier to see in aluminum, and even easier in gold, when compared to simpler protons, Chu explained, because these bigger nuclei have more protons and neutrons, each made up of quarks and gluons.

Today it only takes one and a half hours to make a superconducting particle accelerator at the Department of Energy’s SLAC National Accelerator Laboratory colder than outer space.

“Now you click a button and the machine gets from 4.5 Kelvin down to 2 Kelvin,” said Eric Fauve, director of the Cryogenic team at SLAC.

Continue reading “Helium’s chilling journey to cool a particle accelerator” »

Space is a constant reminder of how little we truly know about our universe. A new international project is hoping to help make a little more sense of things. Next year, researchers from 13 countries will launch a balloon to, hopefully, find high-energy particles that couldn’t have come from Earth.

Watch over 2,400 documentaries for free for 30 days AND get a free Nebula account by signing up at https://curiositystream.com/upandatom and using the code “upandatom”. Once you sign up you’ll get an email about Nebula. If you don’t get one, contact the curiosity stream support team and they will set you up with a free Nebula account right away.

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Continue reading “The Physics of Self-Replication and Nanotechnology” »

Osaka Metropolitan University scientists have developed a simple, rapid method to simultaneously identify multiple food poisoning bacteria, based on color differences in the scattered light by nanometer-scaled organic metal nanohybrid structures (NHs) that bind via antibodies to those bacteria. This method is a promising tool for rapidly detecting bacteria at food manufacturing sites and thereby improving food safety. The findings were published in Analytical Chemistry.

According to the World Health Organization (WHO), every year food poisoning affects 600 million people worldwide—almost 1 in every 10 people—of which 420,000 die. Bacterial tests are conducted to detect food poisoning bacteria at food manufacturing factories, but it takes more than 48 hours to obtain results due to the time required for a bacteria incubation process called culturing. Therefore, there remains a demand for rapid testing methods to eliminate food poisoning accidents.

Responding to this need, the research team led by Professor Hiroshi Shiigi at the Graduate School of Engineering, Osaka Metropolitan University, utilized the optical properties of organic metal NHs—composites consisting of polyaniline particles that encapsulate a large number of metal nanoparticles—to rapidly and simultaneously identify food poisoning-inducing bacteria called enterohemorrhagic Escherichia coli (E. coli O26 and E. coli O157) and Staphylococcus aureus.