We perceive space and time to be continuous, but if the amazing theory of loop quantum gravity is correct, they actually come in discrete pieces.
By Lee Smolin
Want to know the answer to a problem before you even try to solve it? New Scientist has the computer for you.
I am, I’m slightly embarrassed to admit, quoted pretty extensively in the cover story of this week’s New Scientist magazine (alas, only available to subscribers or those willing to shell out $4.95). The story, by Michael Brooks, is about an interesting recent paper by Lucien Hardy of Perimeter Institute, on the power of “quantum gravity computers.” Lucien’s paper considers the following question: by exploiting quantum fluctuations in the causal structure of spacetime, can one efficiently solve problems that are not efficiently solvable with a garden-variety quantum computer?
As I told Brooks, I really do think this is a hell of a question, one that’s intimately related to the challenge of understanding quantum gravity itself. The trouble is that, until an actual quantum theory of gravity chooses to make itself known to us, almost everything we can say about the question is pure speculation.
But of course, pure speculation is what New Scientist gobbles up with french fries and coleslaw. And so, knowing what kind of story they were going to run, I did my best to advocate giving reality at least a few column inches. Fortunately, the end result isn’t quite as bad as I’d feared.
Everyone loves a two-for-one deal—even physicists looking to tackle unanswered questions about the cosmos. Now, scientists at the Department of Energy’s SLAC National Accelerator Laboratory are getting just such a twofer: Particle detectors originally developed to look for dark matter are now in a position to be included aboard the Line Emission Mapper (LEM), a space-based X-ray probe mission proposed for the 2030s.
I think AI agent workflows will drive massive AI progress this year — perhaps even more than the next generation of foundation models. This is an important trend, and I urge everyone who works in AI to pay attention to it.
Demonstrating a long-coherence dual-rail erasure qubit using tunable transmons.
AWS today reported demonstrating an improved approach to quantum error correction that accounts for flip and phase errors in qubits with less overhead (redundant qubits) and on time scales that allow for effective error correction. The work, published today in APS Physical Review X, uses what’s called dual-rail erasure qubits.
Broadly, qubits undergo three types, report AWS researchers Harry Levine and Arbel Haim, in a blog (A new building block for error-corrected quantum computers) today, “[The] vast majority of errors (96%) in our dual-rail qubit are erasure errors (leakage to |00 ⟩), with only a small fraction (4%) of residual (silent) bit-flip and phase-flip errors. This is a strong indicator that if we can accurately flag the erasures, then we can efficiently correct most errors that occur in this system.”
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We don’t live in a universe where matter floats around in empty space… we live in a universe of energy fields that spread throughout the universe and interact with one another, creating everything we see in the process.
Researchers report that lipid droplets in brain cells may be a more significant factor in the development of Alzheimer’s disease than previously thought.
Human brains preserve in diverse environments for at least 12 000 years—new research in Proceedings B this week: https://royalsocietypublishing.org/doi/10.1098/rspb.2023.
Soft tissue preservation in the geological record is relatively rare, and when an archaeologist digs a human skull out of the…
The brain is thought to be among the first human organs to decompose after death. The discovery of brains preserved in the archaeological record is therefore regarded as unusual. Although mechanisms such as dehydration, freezing, saponification, and tanning are known to allow for the preservation of the brain on short time scales in association with other soft tissues (≲4000 years), discoveries of older brains, especially in the absence of other soft tissues, are rare. Here, we collated an archive of more than 4,400 human brains preserved in the archaeological record across approximately 12 000 years, more than 1,300 of which constitute the only soft tissue preserved amongst otherwise skeletonized remains. We found that brains of this type persist on time scales exceeding those preserved by other means, which suggests an unknown mechanism may be responsible for preservation particular to the central nervous system. The untapped archive of preserved ancient brains represents an opportunity for bioarchaeological studies of human evolution, health and disease.
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The Einasto Supercluster is so vast that it would take a light signal 360 million years to get from one end to the other.
