Xtal-WebAry

Friday, April 13, 2012

Majorana particles

Majorana fermions.

Dutch researchers discovered the predicted Majorana particles (quasiparticles that are their own antiparticles). Computer technology based on quantum bits (qubits, 0 AND 1 at the same time) i.s.o. bits (0 or 1) will result in very fast computers, which in turn will speed up development of e.g. medicins.

Fermions vs. Bosons:

"Particles and quasiparticles come in two basic types, fermions and bosons, depending on the type of spin they have. The elementary particles of matter (electrons, quarks and neutrinos) are fermions, while photons and other force carriers are bosons. Particles are paired with antiparticles—antimatter electrons are positrons, etc.—but photons are their own antiparticles. To annihilate, particles and antiparticles must have opposite charge, so Majorana fermions, which are their own antiparticles, need to be electrically-neutral. At present, no fermion is known to be its own antiparticle, although neutrinos may have this property (we don't yet know)."

majorana-fermions-in-a-nanowire

Wednesday, October 5, 2011

NobelprizeChemistry

Nobel Prize Chemistry 2011.

Crystals of golden proportions:
Daniel Shechtman received the 2011 Nobel Prize in Chemistry for his discovery of quasicrystals, perfectly ordered materials that never repeat themselves.

The X-ray diffraction pattern reflects the atom positions in a crystal.
"It's all about symmetry".

The Discovery of Quasicrystals:
The atoms in the crystal in front of Shechtman yielded a forbidden symmetry. It was just as impossible as a football – a sphere – made of only sixcornered polygons. Since then, mosaics with intriguing patterns and the golden ratio in mathematics and art have helped scientists to explain Shechtman’s bewildering observation.

i) http://news.discovery.com/earth/nobel-prize-chemistry-111005.html
ii) http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2011/sciback_2011.pdf
iii) http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2011/info_publ_eng_2011.pdf

iv) CalculArt at the Dennos

Thursday, September 15, 2011

Crystal Cave Palace

"The Crystal's Cave", a Crystal Palace.

"The Crystal's Cave" or "Giant Crystal Cave" is a cave connected to the Naica mine in Mexico. Geologist Juan Manuel García-Ruiz of Granada's University calls this cave with stunning crystals "the Sistine Chapel of crystals". The cave at a depth of 300 m is extremely hot with air temperatures reaching up to 58 °C with 90 to 99 percent humidity. This is due to an underground magma chamber below the cave. The magma heated the ground water and it became saturated with minerals, including large quantities of gypsum (CaSO₄.2H₂O). The hollow space of the cave was filled with this mineral rich hot water and remained filled for about 500,000 years. During this time, the temperature of the water remained very stable at over 50°C. This allowed crystals to form and grow to immense sizes. The main chamber contains giant selenite (crystallized gypsum or CaSO₄.2H₂O) crystals. The cave's largest crystal found to date is 11 m in length, 4 m in diameter and 55 tons in weight. The floor of the cave is covered with perfectly-faceted crystalline blocks. Huge crystal beams jut out from both the blocks and the floor.

At the same level two other caverns were discovered, "The Queen’s Eye Cave" and "The Candle's Cave".

"The Cave of Swords" is located at a depth of 120 m, above the Cave of Crystals, and contains spectacular, smaller (1-2 m long) crystals.

"The Ice Palace" is at a depth of 150 m and is not flooded, but its crystal formations are much smaller, with small 'cauliflower' formations and fine, threadlike crystals.

Naica's Crystal Cave

Wikipedia: Cave of the Crystals

Naica project

BBC News

Video's: Naica Crystal Cave, Naica's Crystal Cave & #1, #2, #3, #4, #5

The heavenly Vatican Sistine Chapel, Terracotta Army of impressive artificial sculpture,

But for us humble crystallographers this Mexican Crystal Palace is an outstanding phenomena of nature,

It’s stunning in beauty and size,

An amazing Crystal Paradise,

Wonder if anybody will ever be able to mount these giant crystals for elucidating their structure.

Friday, June 10, 2011

Strings and branes

Strings and branes.

'M-Theory' is the name of the unknown theory of everything which would combine all five Superstring theories and the Supergravity at 11 dimensions together. It's not a completed theory but rather an approach for producing one. For me it's fascinating to read about (super)strings, (super)gravity, quarks, fermions/bosons, worldline/screens, (mem)branes, curled-up dimensions, supersymmetry, space and time. It makes me even more curious. Recently I heard about two interwoven, non-interacting, worlds at atomic distance. Can you imagine? Two worlds so close and not feeling their existence.

Strings and Branes

Came across a beautiful phrase: "String theory may have the capability to show that all of the happenings in the universe - from the dance of subatomic quarks to the movements of orbiting binary stars, from the big bang to the whirl of celestial galaxies - are reflections of one grand physical principle, one master equation, the theory of everything".

And what about this one?: "In string theory, the elementary particles we observe in particle accelerators could be thought of as the 'musical notes' or excitation modes of elementary strings. The strings in string theory are floating in spacetime. Nonetheless, they have tension".

A brane-world scenario with curled-up dimensions

We still don't know if string theory may be the right theory of nature:
As it stands, string theories are unproved, and perhaps unprovable, as they involve interactions at energy levels far beyond any we can handle. But they are beautiful, to those versed enough in the language of mathematics to follow them. And in their beauty (and perhaps in their impenetrability) they are the heirs to Einstein's - unsuccessful - attempts to produce a unified field theory.