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Category: computing – Page 11

No, Quantum Mechanics does Not Need Complex Numbers

No journal is perfect, and despite Nature being considered a high quality journal, I have recently come across a paper which is, to put it bluntly, is slop. It is a bit of slop easily debunkable by anyone who can do a tiny bit of linear algebra.

The paper is titled “Quantum theory based on real numbers can be experimentally falsified.” The entire paper is misleading because it presents a very specific representation of quantum mechanics based solely on real numbers, shows that it leads to different predictions than traditional quantum theory, and then concludes therefore complex numbers are a necessity for complex theory.

This is obviously false. A complex number is just two real numbers stitched together. Classical computers can’t operate on complex numbers and so they just break them apart into two real floating point numbers and do the equivalent calculations in that form, but then display it as a complex number, and they can reproduce anything you can reproduce using complex numbers. Indeed, my quantum computer simulator I had put together myself uses its own complex matrix library for linear algebra, and each element of the matrix is specified by two real numbers.

Animation technique simulates the motion of squishy objects

The technique simulates elastic objects for animation and other applications, with improved reliability compared to other methods. In comparison, many existing simulation techniques can produce elastic animations that become erratic or sluggish or can even break down entirely.

To achieve this improvement, the MIT researchers uncovered a hidden mathematical structure in equations that capture how elastic materials deform on a computer. By leveraging this property, known as convexity, they designed a method that consistently produces accurate, physically faithful simulations.

Oxford physicists recreate extreme quantum vacuum effects

Physicists at the University of Oxford have successfully simulated how light interacts with empty space – a phenomenon once thought to belong purely to the realm of science fiction. The simulations recreated a bizarre phenomenon predicted by quantum physics, where light appears to be generated from darkness. The findings pave the way for real-world laser facilities to experimentally confirm bizarre quantum phenomena. The results have been published in Communications Physics.

Using advanced computational modelling, a research team led by the University of Oxford, working in partnership with the Instituto Superior Técnico in the University of Lisbon, has achieved the first-ever real-time, three-dimensional simulations of how intense laser beams alter the ‘quantum vacuum’ – a state once assumed to be empty, but which quantum physics predicts is full of virtual electron-positron pairs.

Excitingly, these simulations recreate a bizarre phenomenon predicted by quantum physics, known as vacuum four-wave mixing. This states that the combined electromagnetic field of three focused laser pulses can polarise the virtual electron-positron pairs of a vacuum, causing photons to bounce off each other like billiard balls – generating a fourth laser beam in a ‘light from darkness’ process. These events could act as a probe of new physics at extremely high intensities.

New study visualizes platinum doping on ultrathin 2D material with atomic precision

A popular 2D active material, molybdenum disulfide (MoS2), just got a platinum upgrade at an atomic level. A study led by researchers from the University of Vienna and Vienna University of Technology embedded individual platinum (Pt) atoms onto an ultrathin MoS2 monolayer and, for the first time, pinpointed their exact positions within the lattice with atomic precision.

The study, published in the journal Nano Letters, achieved this feat with an innovative approach that integrates targeted defect creation in the MoS2 monolayer, controlled platinum deposition, and a high-contrast computational microscopic imaging technique—ptychography.

The researchers believe that this new strategy for ultra-precise doping and mapping offers new pathways for understanding and engineering atomic-scale features in 2D systems.

Predicting chemical storm fronts: Framework enables predictive control over patterned polymer formation

Imagine being tasked with baking a soufflé, except the only instruction provided is an ingredient list without any measurements or temperatures.

It would likely take an enormous amount of time, effort and ingredients to bake the perfect soufflé. It would require trial and error—tweaking ingredient measurements, altering the temperature and baking duration—but what if you had a model that could predict the final product before anything ever went into the mixing bowl? It would not only save weeks’ worth of time and resources but could also provide useful details like why and how the soufflé rose and collapsed when it did or why the texture didn’t turn out how you expected.

Researchers at the Beckman Institute for Advanced Science and Technology aren’t quite baking soufflés. Instead, they developed a that digs into the chemical “recipe” of polymer manufacturing to provide predictive control over how materials self-organize to give rise to new textures and properties.

Novel crystal strategy yields brighter, longer-lasting all-inorganic perovskite LEDs

Perovskite has broad application prospects in solar cells, light-emitting diodes (LEDs), and detectors due to its high luminescent efficiency and low cost. However, electrons and holes in traditional perovskite materials often struggle to effectively recombine and emit light. As a result, the strongly space-confined method is commonly employed to improve luminescence efficiency. Furthermore, how to enhance the brightness of LEDs and extend their lifespan has become a top research priority in this field.

In a study published in Nature, Prof. Xiao Zhengguo’s team from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences has proposed a novel strategy based on weakly space-confined, large-grain crystals of all-inorganic perovskite to prepare with larger crystalline grains and higher temperature resistance. Researchers increased the brightness of perovskite LEDs (PeLEDs) to over 1.16 million nits and extended their lifespan to more than 180,000 hours.

Researchers developed the strategy based on the weakly space-confined technique. They first added specific compounds—hypophosphorous acid and ammonium chloride—to the perovskite material. Then, they prepared a new type of perovskite thin film with larger crystalline grains and fewer defects using a high-temperature annealing process.

Quantum mechanics provide truly random numbers on demand

Randomness is incredibly useful. People often draw straws, throw dice or flip coins to make fair choices. Random numbers can enable auditors to make completely unbiased selections. Randomness is also key in security; if a password or code is an unguessable string of numbers, it’s harder to crack. Many of our cryptographic systems today use random number generators to produce secure keys.

But how do you know that a random number is truly random?

Classical computer algorithms can only create pseudorandom numbers, and someone with enough knowledge of the algorithm or the system could manipulate it or predict the next number. An expert in sleight of hand could rig a coin flip to guarantee a heads or tails result. Even the most careful coin flips can have bias; with enough study, their outcomes could be predicted.

IBM claims ‘real world’ edge in quantum computing race

Technology veteran IBM on Tuesday laid out a plan to have a “practical” quantum computer tackling big problems before the end of this decade.

Current quantum computers are still experimental and face significant challenges, including high error rates. Companies like IBM, Google, and others are working to build more stable and scalable quantum systems.

Real-world innovations that quantum computing has the potential to tackle include developing better fuels, materials, pharmaceuticals, or even new elements. However, delivering on that promise has always seemed some way off.