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Demonstration of universal time-reversal for qubit processes

In quantum mechanics, the unitary nature of time evolution makes it intrinsically reversible, given control over the system in question. Remarkably, there have been several recent demonstrations of protocols for reverting unknown unitaries in scenarios where even the interactions with the target system are unknown. These protocols are limited by their probabilistic nature, raising the fundamental question of whether time-reversal could be performed deterministically. Here we show that quantum physics indeed allows for this by exploiting the non-commuting nature of quantum operators, and demonstrate a recursive protocol for two-level quantum systems with an arbitrarily high probability of success. Using a photonic platform, we achieve an average rewinding fidelity of over 95%. Our protocol, requiring no knowledge of the quantum process to be rewound, is optimal in its running time, and brings quantum rewinding into a regime of practical relevance.

Published by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articleโ€™s title, journal citation, and DOI.

Gene Expression in Neurons Solves a Brain Evolution Puzzle

๐“๐ก๐ž ๐ง๐ž๐จ๐œ๐จ๐ซ๐ญ๐ž๐ฑ ๐ฌ๐ญ๐š๐ง๐๐ฌ ๐จ๐ฎ๐ญ ๐š๐ฌ ๐š ๐ฌ๐ญ๐ฎ๐ง๐ง๐ข๐ง๐  ๐š๐œ๐ก๐ข๐ž๐ฏ๐ž๐ฆ๐ž๐ง๐ญ ๐จ๐Ÿ ๐›๐ข๐จ๐ฅ๐จ๐ ๐ข๐œ๐š๐ฅ ๐ž๐ฏ๐จ๐ฅ๐ฎ๐ญ๐ข๐จ๐ง. ๐€๐ฅ๐ฅ ๐ฆ๐š๐ฆ๐ฆ๐š๐ฅ๐ฌ ๐ก๐š๐ฏ๐ž ๐ญ๐ก๐ข๐ฌ ๐ฌ๐ฐ๐š๐ญ๐ก ๐จ๐Ÿ ๐ญ๐ข๐ฌ๐ฌ๐ฎ๐ž ๐œ๐จ๐ฏ๐ž๐ซ๐ข๐ง๐  ๐ญ๐ก๐ž๐ข๐ซ ๐›๐ซ๐š๐ข๐ง, ๐š๐ง๐ ๐ญ๐ก๐ž ๐ฌ๐ข๐ฑ ๐ฅ๐š๐ฒ๐ž๐ซ๐ฌ ๐จ๐Ÿ ๐๐ž๐ง๐ฌ๐ž๐ฅ๐ฒ ๐ฉ๐š๐œ๐ค๐ž๐ ๐ง๐ž๐ฎ๐ซ๐จ๐ง๐ฌ ๐ฐ๐ข๐ญ๐ก๐ข๐ง ๐ข๐ญ ๐ก๐š๐ง๐๐ฅ๐ž ๐ญ๐ก๐ž ๐ฌ๐จ๐ฉ๐ก๐ข๐ฌ๐ญ๐ข๐œ๐š๐ญ๐ž๐ ๐œ๐จ๐ฆ๐ฉ๐ฎ๐ญ๐š๐ญ๐ข๐จ๐ง๐ฌ ๐š๐ง๐ ๐š๐ฌ๐ฌ๐จ๐œ๐ข๐š๐ญ๐ข๐จ๐ง๐ฌ ๐ญ๐ก๐š๐ญ ๐ฉ๐ซ๐จ๐๐ฎ๐œ๐ž ๐œ๐จ๐ ๐ง๐ข๐ญ๐ข๐ฏ๐ž ๐ฉ๐ซ๐จ๐ฐ๐ž๐ฌ๐ฌ. ๐’๐ข๐ง๐œ๐ž ๐ง๐จ ๐š๐ง๐ข๐ฆ๐š๐ฅ๐ฌ ๐จ๐ญ๐ก๐ž๐ซ ๐ญ๐ก๐š๐ง ๐ฆ๐š๐ฆ๐ฆ๐š๐ฅ๐ฌ ๐ก๐š๐ฏ๐ž ๐š ๐ง๐ž๐จ๐œ๐จ๐ซ๐ญ๐ž๐ฑ, ๐ฌ๐œ๐ข๐ž๐ง๐ญ๐ข๐ฌ๐ญ๐ฌ ๐ก๐š๐ฏ๐ž ๐ฐ๐จ๐ง๐๐ž๐ซ๐ž๐ ๐ก๐จ๐ฐ ๐ฌ๐ฎ๐œ๐ก ๐š ๐œ๐จ๐ฆ๐ฉ๐ฅ๐ž๐ฑ ๐›๐ซ๐š๐ข๐ง ๐ซ๐ž๐ ๐ข๐จ๐ง ๐ž๐ฏ๐จ๐ฅ๐ฏ๐ž๐.

The brains of reptiles seemed to offer a clue. Not only are reptiles the closest living relatives of mammals, but their brains have a three-layered structure called a dorsal ventricular ridge, or DVR, with functional similarities to the neocortex.


The neocortex stands out as a stunning achievement of biological evolution. All mammals have this swath of tissue covering their brain, and the six layers of densely packed neurons within it handle the sophisticated computations and associations that produce cognitive prowess. Since no animals other than mammals have a neocortex, scientists have wondered how such a complex brain region evolved.

Now, however, by analyzing molecular details invisible to the human eye, scientists have refuted that view. By looking at patterns of gene expression in individual brain cells, researchers at Columbia University showed that despite the anatomical similarities, the neocortex in mammals and the DVR in reptiles are unrelated. Instead, mammals seem to have evolved the neocortex as an entirely new brain region, one built without a trace of what came before it. The neocortex is composed of new types of neurons that seem to have no precedent in ancestral animals.

Number of fires in the Brazilian Amazon in August-September 2022 was highest since 2010

The number of active fires recorded in the Brazilian Amazon in August-September 2022 was the highest since 2010, according to an article published in the journal Nature Ecology & Evolution. Besides the record number of fires (74,398), the researchers found they were due not to extreme drought, as in 2010, but to recent deforestation by humans.

โ€œThe idea of publishing our findings came up when we analyzed data provided free of charge by the Queimadas program,โ€ said Guilherme Mataveli, first author of the article. โ€˜Queimadasโ€™ in Portuguese means burnings, and he was referring to the forest monitoring service run by the National Space Research Institute (INPE). Mataveli is currently a postdoctoral researcher in INPEโ€™s Earth Observation and Geoinformatics Division.

The number of fires typically rises every year in August and September, when the weather favors fire in about half of the Amazon. โ€œBut the surge in the number of fires in 2010 was due to an extreme drought event that occurred in a large part of the region, whereas nothing similar occurred in 2022, so other factors must have been to blame,โ€ Mataveli said.

Hubble Telescope Gauges Mass of Lone White Dwarf Using Einsteinโ€™s Gravitational Microlensing

Science Daily reports that the astronomers found out that the mass of this lone white dwarf is equivalent to 56% of the sunโ€™s weight. It aligns with previous theoretical predictions regarding the white dwarfโ€™s mass, and it also sheds light on persisting theories regarding the evolution of these white dwarfs as a result of usual star evolution. The interesting observation grants further understanding of theories regarding white dwarf composition and structure.

According to the Space Academy, the astronomers made use of the renowned Hubble Space Telescope to gauge this lone white dwarfโ€™s mass. The dwarf is known as LAWD 37.

Why Carl Sagan believed that science is a source of spirituality

Yes, the world has some serious problems, but if we did not have problems, we would never be forced to find new solutions. Problems push progress forward. Letโ€™s embrace our ultimate existential challenges and come together to solve them. It is time to forget our differences and think of ourselves only as humans, engaged in a common biological and moral struggle. If the cosmic perspective, and the philosophy of poetic meta-naturalism, or some similar world-view of evolution and emergence, can build a bridge between the reductionist worldview and the religions of the world, then we can be optimistic that a new level of order and functionality will emerge from the current sea of chaos.

Knowledge is enlightenment, knowledge is transcendence, and knowledge is power. The tendency toward disorder described by the second law requires that life acquire knowledge forever, giving us all an individual and collective purpose by creating the constraint that forces us to create. By becoming aware of our emergent purpose, we can live more meaningful lives, in harmony with one another and with the aspirations of nature. You are not a cosmic accident. You are a cosmic imperative.

How a single-gene change led to a new species of monkeyflower

Monkeyflowers glow in a rich assortment of colors, from yellow to pink to deep red-orange. But about 5 million years ago, some of them lost their yellow. In the Feb. 10 issue of Science, UConn botanists explain what happened genetically to jettison the yellow pigment, and the implications for the evolution of species.

Monkeyflowers are famous for growing in harsh, mineral-rich soils where other plants canโ€™t. They are also famously diverse in shape and color. Monkeyflowers also provide a textbook example of how a single-gene change can make a . In this case, a monkeyflower species lost the yellow pigments in the petals but gained pink about 5 million years ago, attracting bees for pollination. Later, a descendent species accumulated mutations in a gene called YUP that recovered the yellow pigments and led to production of red flowers. The species stopped attracting bees. Instead, hummingbirds pollinated it, isolating the red flowers genetically and creating a new species.

UConn botanist Yaowu Yuan and postdoctoral researcher Mei Liang (currently a professor at South China Agricultural University), with collaborators from four other institutes, have now shown exactly which gene changed to prevent monkeyflowers from making yellow. Their research, published this week in Science, adds weight to a theory that new genes create phenotypic diversity and even new species.

Biological Big Bang: How we solved Darwinโ€™s dilemma

Evolutionโ€™s rapid pace after the Cambrian explosion

Though the work of Schopf and other paleobiologists continues to fill in the Precambrian fossil record, questions remain about the pace of the Cambrian explosion. What triggered life to evolve so fast?

The question has intrigued scientists of many disciplines for decades. Interdisciplinary collaboration has wrought a wealth of evidence from diverse perspectives โ€” geochemical, paleoenvironmental, geological, anatomical, and taxonomic โ€” that describes how biological organisms evolved in concert with changing environmental conditions.

A 319-million-year-old brain has been discovered. It could be the oldest of its kind

A scan of the skull of a 319-million-year-old fossilized fish has led to the discovery of the oldest example of a well-preserved vertebrate brain, shining a new light on the early evolution of bony fish.

The fossil of the skull belonging to the extinct Coccocephalus wildi was found in a coal mine in England more than a century ago, according to researchers of the study published in the journal Nature on Wednesday.

The fossil is the only known specimen of the fish species so scientists from the University of Michigan in the US and the University of Birmingham in the UK used the nondestructive imaging technique of computed tomography (CT) scanning to look inside its skull and examine its internal bodily structure.