Quantum Computer Manufacturing Time Crystals Selected in Quantum Magazine's Six Progress in Physics in 2021

Recently, the popular science website Quanta Magazine selected the six major advances in physics in 2021, and two of them were selected for research on quantum computing, including Google’s quantum computer to make time crystals.
 
The six major developments are as follows:

Fundamental Particles Aren’t Doing What’s Expected

Given enough time and data, most anomalies turn out to be attractive statistical artifacts, false fodder for physicists’ daydreams. Rare are the hints of new phenomena that stand up to decades of investigation. But this April, physicists announced the first results of an experiment designed specifically to chase just such an anomaly, one involving the intrinsic magnetism of a particle called the muon. They found that the experimental value differs from the predictions of the Standard Model of particle physics by a wide margin, confirming an anomaly first hinted at in 2001. The result suggests that there might be extra particles flying around that we don’t yet know about — or, better yet, entirely new physical laws. The result dovetails with decades’ worth of strange neutrino behaviors — results that have led physicists to suggest an entirely new “dark sector” of particles and forces largely inaccessible to us.

Thermodynamic Laws Get Cleverly Evaded

At first glance, a time crystal would appear to violate one of nature’s most sacred commandments: Nothing comes for free. This object, first conceived (in a slightly different form) in 2012, would flip back and forth between two distinct states forever, with no energy lost or gained. (A laser triggers the change, but the time crystal does not absorb any net energy from the laser.) This summer, researchers announced that they had finally created it using one of Google’s quantum computers. In doing so, they forged a novel phase of matter — the first out-of-equilibrium phase, and the first object to spontaneously break time-translation symmetry. That’s in addition to appearing to violate one of nature’s most cherished laws. “The consequence is amazing,” said Roderich Moessner, a co-author on the paper. “You evade the second law of thermodynamics.” Maxwell’s demon would be proud.

Galactic Megastructures Identified

One problem with studying the Milky Way galaxy is that we’re stuck inside it. That makes it hard to tell if a smear on the night sky is a truly enormous galaxy-size structure or a star-size smudge viewed relatively close up. For decades, astronomers assumed that just such a smear was coming from a nearby object — perhaps the remnant of a long-ago supernova. But a recent analysis of X-ray data found a matching smear on the other side of the Milky Way, one that helps to trace out a pair of galaxy-size bubbles 45,000 light-years tall. Astronomers suspect that the bubbles might be evidence of an eruption from millions of years ago — the detritus of a half-eaten cloud of gas that ventured too close to the Milky Way’s supermassive black hole.

Quantum Computing Efforts Confront Controversy

Quantum computing is infamously difficult, as the individual quantum bits (or qubits) that make up a quantum processor are remarkably fragile. That’s why many have been excited about a potential approach to quantum computing that uses sturdy “topological” qubits — quantum bits whose information is inexorably braided into their physical structure. In recent years, various teams of researchers have published papers claiming to have created these qubits in the lab. But now controversy has engulfed the field. Other phenomena can convincingly masquerade as one of these topological qubits, and independent researchers aren’t convinced of anything they’ve seen. Retractions have followed. The field of topological quantum computing still has promise, but the task has shown itself to be even more difficult than researchers first imagined.
 

Long-Hidden Black Holes Reveal Cosmic Quirks

A new and even more detailed image of the black hole at the center of galaxy M87 has put to rest a decades-old question: How do supermassive black holes, those galaxy-anchoring anomalies, launch jets of matter and energy thousands of light-years into space? The M87 images revealed a powerful spiral magnetic field around the black hole — a key ingredient in a 44-year-old model of jet formation called the Blandford-Znajek process. Researchers this year also made one of the first convincing discoveries of a midsize black hole, one smaller than supermassive anchors but larger than a star-size shell. Equipped with a new search strategy, researchers hope that the 55,000-solar-mass discovery will be the first of many.