Tag: physics

1D carbon

with a tensile strength of 300 gigapascal, this material is 5x stronger than what is deemed necessary for a space elevator. leave in some safety margin and you can still build a much less massive space elevator (once you synthesize 100Ks of km of this stuff, of course)

Amplituhedron

Physicists have discovered a jewel-like geometric object that dramatically simplifies calculations of particle interactions and challenges the notion that space and time are fundamental components of reality. “This is completely new and very much simpler than anything that has been done before” Interactions that were previously calculated with mathematical formulas 1000s of terms long can now be described by computing the volume of the corresponding jewel-like “amplituhedron,” which yields an equivalent 1-term expression.

this is remarkable. usually these theories are only accessible to the most mathematically gifted (cf string theory / ed witten)

Negative temperatures

With positive temperatures, atoms more likely occupy low-energy states than high-energy states, a pattern known as Boltzmann distribution in physics. When an object is heated, its atoms can reach higher energy levels. At absolute 0, atoms would occupy the lowest energy state. At an infinite temperature, atoms would occupy all energy states. Negative temperatures then are the opposite of positive temperatures — atoms more likely occupy high-energy states than low-energy states. “The inverted Boltzmann distribution is the hallmark of negative absolute temperature, and this is what we have achieved. Yet the gas is not colder than 0 kelvin, but hotter. It is even hotter than at any positive temperature — the temperature scale simply does not end at infinity, but jumps to negative values instead.” Objects with negative temperatures behave in very odd ways. For instance, energy typically flows from objects with a higher positive temperature to ones with a lower positive temperature — that is, hotter objects heat up cooler objects, and colder objects cool down hotter ones, until they reach a common temperature. However, energy will always flow from objects with negative temperature to ones with positive temperatures. In this sense, objects with negative temperatures are always hotter than ones with positive temperatures.

most mind-blowing science year of the year (har har), temperatures below absolute zero. also, your sense of what temperature means is wrong.

Majorana fermions

“The search for this particle is for condensed-matter physicists what the Higgs boson search was for high-energy particle physicists. It is a very peculiar object because it is a fermion yet it is its own antiparticle with zero mass and zero charge. Whether or not these particles will work for quantum computing has yet to be seen, but in the process of trying we will learn a lot of unknown quantum physics,. This could open the door to a whole new field of the topological effects of quantum mechanics.”

2D MoS2

researchers — who struggled for several years to build electronic circuits out of graphene with very limited results (except for radio-frequency applications) — have now succeeded in making a variety of electronic components from an amazing new material: a 2D version of molybdenum disulfide (MoS2). the material could help usher in radically new products, from whole walls that glow to clothing with embedded electronics to glasses with built-in display screens. “It’s the most exciting time for electronics in the last 20 or 30 years. It’s opening up the door to a completely new domain of electronic materials and devices.”

in general, materials science remains under-appreciated as the source of much of our wealth and comfort, both current and future.