Lifeboat Foundation

Light offers an irreplaceable way to interact with our universe. It can travel across galactic distances and collide with our atmosphere, creating a shower of particles that tell a story of past astronomical events. Here on earth, controlling light lets us send data from one side of the planet to the other.

Given its broad utility, it’s no surprise that light plays a critical role in enabling 21st century quantum information applications. For example, scientists use laser light to precisely control atoms, turning them into ultra-sensitive measures of time, acceleration, and even gravity. Currently, such early quantum technology is limited by size—state-of-the-art systems would not fit on a dining room table, let alone a chip. For practical use, scientists and engineers need to miniaturize quantum devices, which requires re-thinking certain components for harnessing light.

Now IQUIST member Gaurav Bahl and his research group have designed a simple, compact photonic circuit that uses sound waves to rein in light. The new study, published in the October 21 issue of the journal Nature Photonics, demonstrates a powerful way to isolate, or control the directionality of light. The team’s measurements show that their approach to isolation currently outperforms all previous on-chip alternatives and is optimized for compatibility with atom-based sensors.

The Large Hadron Collider (LHC) sparked worldwide excitement in March as particle physicists reported tantalizing evidence for new physics – potentially a new force of nature.

Now, our new result, yet to be peer reviewed, from CERN’s gargantuan particle collider seems to be adding further support to the idea.

Our current best theory of particles and forces is known as the standard model, which describes everything we know about the physical stuff that makes up the world around us with unerring accuracy.

The team used a high-resolution atomic force microscope (AFM) operating in a controlled environment at Princeton’s Imaging and Analysis Center. The AFM probe, whose tip ends in a single copper atom, was moved gradually closer to the iron-carbon bond until it was ruptured. The researchers measured the mechanical forces applied at the moment of breakage, which was visible in an image captured by the microscope. A team from Princeton University, the University of Texas-Austin and ExxonMobil reported the results in a paper published Sept. 24 in Nature Communications.

“It’s an incredible image—being able to actually see a single small molecule on a surface with another one bonded to it is amazing,” said coauthor Craig Arnold, the Susan Dod Brown Professor of Mechanical and Aerospace Engineering and director of the Princeton Institute for the Science and Technology of Materials (PRISM).

“The fact that we could characterize that particular bond, both by pulling on it and pushing on it, allows us to understand a lot more about the nature of these kinds of bonds—their strength, how they interact—and this has all sorts of implications, particularly for catalysis, where you have a molecule on a surface and then something interacts with it and causes it to break apart,” said Arnold.

Beauty quarks are unstable, living on average just for about 1.5 trillionths of a second before decaying into other particles. The way beauty quarks decay can be strongly influenced by the existence of other fundamental particles or forces. When a beauty quark decays, it transforms into a set of lighter particles, such as electrons, through the influence of the weak force. One of the ways a new force of nature might make itself known to us is by subtly changing how often beauty quarks decay into different types of particles.

The March paper was based on data from the LHCb experiment, one of four giant particle detectors that record the outcome of the ultra-high-energy collisions produced by the LHC. (The “b” in LHCb stands for “beauty”.) It found that beauty quarks were decaying into electrons and their heavier cousins called muons at different rates. This was truly surprising because, according to the standard model, the muon is basically a carbon copy of the electron – identical in every way except for being around 200 times heavier. This means that all the forces should pull on electrons and muons with equal strength – when a beauty quark decays into electrons or muons via the weak force, it ought to do so equally often.

Instead, my colleagues found that the muon decay was only happening about 85% as often as the electron decay. Assuming the result is correct, the only way to explain such an effect would be if some new force of nature that pulls on electrons and muons differently is interfering with how beauty quarks decay.

Magnetic solids can be demagnetized quickly with a short laser pulse, and there are already so-called HAMR (Heat Assisted Magnetic Recording) memories on the market that function according to this principle. However, the microscopic mechanisms of ultrafast demagnetization remain unclear. Now, a team at HZB has developed a new method at BESSY II to quantify one of these mechanisms and they have applied it to the rare-earth element Gadolinium, whose magnetic properties are caused by electrons on both the 4f and the 5d shells. This study completes a series of experiments done by the team on nickel and iron-nickel alloys. Understanding these mechanisms is useful for developing ultrafast data storage devices.

New materials should make information processing more efficient, for example, through ultrafast spintronic devices that store data with less energy input. But to date, the microscopic mechanisms of ultrafast demagnetization are not fully understood. Typically, the process of demagnetization is studied by sending an ultrashort laser pulse to the sample, thereby heating it up, and then analyzing how the system evolves in the first picoseconds afterward.

The LCLS-II will be the world’s brightest x-ray laser when it delivers “first light” in the early 2020’s. With this superconducting accelerator online, scientists will be able to see the hidden world of atoms and molecules like never before.
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Cover image credit: Nathan Taylor.

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Scientists just broke the record for the coldest temperature ever measured in a lab: They achieved the bone-chilling temperature of 38 trillionths of a degree above-273.15 Celsius by dropping magnetized gas 393 feet (120 meters) down a tower.

The team of German researchers was investigating the quantum properties of a so-called fifth state of matter: Bose-Einstein condensate (BEC), a derivative of gas that exists only under ultra-cold conditions. While in the BEC phase, matter itself begins to behave like one large atom, making it an especially appealing subject for quantum physicists who are interested in the mechanics of subatomic particles.

No particle we know of can explain what’s going on.

When the Nobel Prize-winning US physicist Robert Hofstadter and his team fired highly energetic electrons at a small vial of hydrogen at the Stanford Linear Accelerator Center in 1,956 they opened the door to a new era of physics.

Until then, it was thought that protons and neutrons, which make up an atom’s nucleus, were the most fundamental particles in nature.

They were considered to be ‘dots’ in space, lacking physical dimensions. Now it suddenly became clear that these particles were not fundamental at all, and had a size and complex internal structure as well.