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Physicists Confirm The Existence of a Third Form of Magnetism

Slashdot
3 months 1 week ago
Scientists have demonstrated control over a newly theorized type of magnetism, known as altermagnetism, by manipulating nanoscale magnetic whirlpools in an ultra-thin wafer of manganese telluride. "Our experimental work has provided a bridge between theoretical concepts and real-life realization, which hopefully illuminates a path to developing altermagnetic materials for practical applications," says University of Nottingham physicist Oliver Amin, who led the research with PhD student Alfred Dal Din. From the report: Using a device that accelerates electrons to blinding speeds, a team led by researchers from the University of Nottingham showered an ultra-thin wafer of manganese telluride with X-rays of different polarizations, revealing changes on a nanometer scale reflecting magnetic activity unlike anything seen before. [...] More recently, a third configuration of particles in ferromagnetic materials was theorized. In what's referred to as altermagnetism, particles are arranged in a canceling fashion like antiferromagnetism, yet rotated just enough to allow for confined forces on a nanoscale -- not enough to pin a grocery list to your freezer, but with discrete properties that engineers are keen to manipulate into storing data or channeling energy. "Altermagnets consist of magnetic moments that point antiparallel to their neighbors," explains University of Nottingham physicist Peter Wadley. "However, each part of the crystal hosting these tiny moments is rotated with respect to its neighbors. This is like antiferromagnetism with a twist! But this subtle difference has huge ramifications." Experiments have since confirmed the existence of this in-between 'alter' magnetism. However, none had directly demonstrated it was possible to manipulate its tiny magnetic vortices in ways that might prove useful. Wadley and his colleagues demonstrated that a sheet of manganese telluride just a few nanometers thick could be distorted in ways that intentionally created distinct magnetic whirlpools on the wafer's surface. "Our experimental work has provided a bridge between theoretical concepts and real-life realization, which hopefully illuminates a path to developing altermagnetic materials for practical applications," says University of Nottingham physicist Oliver Amin. This research was published in the journal Nature.

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BeauHD

Google: How to make any AMD Zen CPU always generate 4 as a random number

The Register
3 months 1 week ago
Malicious microcode vulnerability discovered, fixes rolling out for Epycs at least

Googlers have not only figured out how to break AMD's security – allowing them to load unofficial microcode into its processors to modify the silicon's behavior as they wish – but also demonstrated this by producing a microcode patch that makes the chips always output 4 when asked for a random number.…

Iain Thomson

Representative Line: Whitespace: A Frontier

The Daily WTF
3 months 1 week ago

Tim has been working on a large C++ project which has been around for many, many years. It's a tool built for, in Tim's words, "an esoteric field", and most of the developers over the past 30 years have been PhD students.

This particular representative line is present with its original whitespace, and the original variable names. It has been in the code base since 2010.

Assignment::Ptr ra = Assignment::makeAssignment(I, addr, func, block, RA);

The extra bonus is that Assignment::Ptr is actually an alias for boost::shared_ptr<Assignment>. As you might gather from the name shared_ptr, that's a reference-counted way to manage pointers to memory, and thus avoid memory leaks.

The developers just couldn't tolerate using the names provided by their widely used library solving a widely understood problem, and needed to invent their own names, which made the code less clear. The same is true for makeAssignment. And this pattern is used for nearly every class, because the developers involved didn't understand object lifetimes, when to allow things to be stack allocated, or how ownership should really work in an application.

This is hardly the only WTF in the code, but Tim says:

Preceding the 98 standard, there is a LOT of C-with-classes code. But this representative line speaks to the complete lack of thought that has gone into much of codebase. That whitespace is as-is from the source.

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Remy Porter

USPS Halts All Packages From China, Sending the Ecommerce Industry Into Chaos

Slashdot
3 months 1 week ago
The United States Postal Service has suspended all package shipments from China and Hong Kong following President Donald Trump's decision to eliminate the de minimis exemption, which previously allowed small packages under $800 to enter the U.S. without import duties. "The move could potentially create chaos and confusion across the online shopping industry, as well as make purchases more expensive for consumers, especially because many global manufacturers and internet sellers are located in China," reports Wired. "Shoppers are now on the hook not only for the additional 10 percent tariff, but also whatever original tax rate their products were exempted from until Tuesday." From the report: Cindy Allen, who has worked in international trade for over 30 years and is the CEO of the consulting firm Trade Force Multiplier, gave WIRED an example of how much additional cost the tariff will incur: A woman's dress made of synthetic fiber shipped from China through de minimis will now be subject to a regular 16 percent tariff, a 7.5 percent Section 301 duty specifically for goods from China, the new 10 percent tariff required by Trump, additional processing fees and customs brokerage fees, and perhaps increased brokering and handling costs due to the sudden change in rules. "Will the dress that was $5 now cost $5.50 or $15?" says Allen. "That we don't know. It depends on how those retailers react and change their business models." In the immediate term, clearing customs will become a challenge for most ecommerce companies. Their long-term concern, though, is the potential impact on profitability. The appeal of Temu and Shein and similar Chinese ecommerce companies is how affordable their products are. If that changes, the ecommerce landscape and consumer behavior in the US may change significantly as well. While the USPS has announced the suspension of accepting any parcels from China and Hong Kong, CBP hasn't elaborated on how the agency will enforce Trump's new tariffs other than saying in an announcement that it will reject de minimis exemption requests from China starting today.

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BeauHD