Tag: science

40 ka art tools

Different powders were good for different uses. “Fine, clayish sorted ochre powder is more suitable for cosmetic or symbolic activities such as body painting, whereas mixed grain size ochre would be more adapted to utilitarian activities such as hafting,” write Rosso and colleagues. This was a workshop devoted to producing ochres that could be used in adhesives and in paints or dyes. Humanity’s earliest experiments with symbolism can be traced back to the twin births of art and engineering. 10Ks of years ago, our tool-obsessed brains allowed us to convert iron-rich rocks into beautiful adornments—and better hammers, too.

Meridian Reconciliation

A cooperation to make sure Easter is celebrated at the liturgically correct date.

Bologna’s Basilica of San Petronio is not the only example of a meridian line, although it was considered to be the most accurate. Santa Maria degli Angeli in Rome has a beautifully realized and particularly grandiose example cutting through its nave; Saint-Sulpice in Paris hosts its own, as does Santa Maria del Fiore in Florence; a church tightly nestled in the packed streets of Fossombrone, Italy, bears a meridian line; the heavily worn remains of a line are still visible in the cloisters of England’s Durham Cathedral; and the duomos of Milan and Palermo also contain their own meridian lines. To determine exactly when the equinox would be, in the future—and, thus, when Easter should properly be celebrated—a more subtle and astronomically precise tool of measurement was required. A meridian line. The Catholic Church supported astronomy for more than 600 years, from medieval times to the Enlightenment. This sponsorship continues into the 21st century

Zeptosecond measurement

Physicists have measured photoionization, in which an electron exits a helium atom after excitation by light – for the first time with zeptosecond (10^-21 seconds) precision. This is the greatest accuracy of time determination of an event in the microcosm ever achieved, as well as the first absolute determination of the timescale of photoionization.

Metallic Hydrogen

Harvard researchers have studied and observed solid hydrogen under pressure at low temperatures. With increasing pressure we observe changes in the sample, going from transparent, to black, to a reflective metal, the latter studied at a pressure of 495 GPa. If it stays a metal at room temperature and after releasing pressure and was also a superconductor then it would be the holy grail of physics. Controlled nuclear fusion, production of metallic hydrogen, and high temperature superconductivity have been listed as the top 3 problems of physics. These problems all involve hydrogen and its isotopes.

Chromatin Loops

“It’s quite spectacular that the structure of an entire chromosome would rely on a small DNA sequence somewhere in the middle”. Scientists have long suspected that abnormal genome folding may cause diseases, and several new studies have identified links between genome architecture and biological development. A rearrangement of DNA in a noncoding region of the genome causes limb malformations during development by changing chromatin folding. Other researchers are using CRISPR to investigate whether changes to genome architecture affects the ability of parasites like Trypanosoma, the cause of African sleeping sickness, to evade the immune system. It’s becoming apparent that in the genome, “nothing makes sense except in 3D.”

Maxwell’s Demon

As far back as 1867, physicist James Clerk Maxwell described a hypothetical way to violate the Second Law: if a small theoretical being sat at the door between the hot and cold rooms and only let through particles traveling at a certain speed. This theoretical imp is called “Maxwell’s demon.”

“Although the violation is only on the local scale, the implications are far-reaching. This provides us a platform for the practical realization of a quantum Maxwell’s demon, which could make possible a local quantum perpetual motion machine.”

Private exoplanet hunting

Unlike the Kepler Space Telescope—which monitored 100k stars and looked for slight dimming to determine when planets passed in front of their parent stars—Project Blue will use high-contrast imaging. Technical studies have shown that, with an advanced coronagraph to block light from the stars and data processing techniques, such a telescope could reject light from the 2 stars at a rate of 10B to 1. This is sufficient to allow direct imaging of a planet with observations made over the course of several years. Put another way, such an observation system is akin to detecting a firefly next to a lighthouse 16km away.

The proposed telescope should be able to resolve a world that is 0.5 to 1.5 times of the size of Earth and orbiting within the host star’s “habitable zone,” where water theoretically could exist on the surface. Based on Kepler’s data, with 2 Sun-like stars to search around, the odds of at least 1 terrestrial planet in the habitable zone is 80%.

Quantum Supremacy

Quantum supremacy can be achieved in the near-term with 50 superconducting qubits. We introduce cross entropy as a useful benchmark of quantum circuits which approximates the circuit fidelity. We show that the cross entropy can be efficiently measured when circuit simulations are available. Beyond the classically tractable regime, the cross entropy can be extrapolated and compared with theoretical estimates of circuit fidelity to define a practical quantum supremacy test.

As of 2018, Google and NASA are testing it:

Google and NASA have an agreement to compare Google 72-qubit quantum Bristlecone chip and possibly near-term follow-up quantum chips against regular supercomputers.

And John Preskill writes about how he coined the term:

In 2012, I proposed the term “quantum supremacy” to describe the point where quantum computers can do things that classical computers can’t, regardless of whether those tasks are useful. Where do we go from here? Naturally, Google and other hardware builders hope to find practical applications for their quantum devices. A much larger quantum computer might help researchers design new materials and chemical compounds or build better tools for machine learning, but a noisy quantum computer with a few 100 qubits might not be capable of anything useful. Still, we have ideas about how to use NISQ computers that we’re eager to try, which might yield better methods for optimization or more accurate physical simulations, but we’re not sure if any of these will pan out. It will be fun to play with NISQ technology to learn more about what it can do. I expect that quantum computers will have a transformative effect on society, but this may still be decades away.