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Entries in quantum (32)

Tuesday
Sep282010

Uncertainty in the world

Uncertainty in the world, from quantum mechanics to string theory... One of the most counter-intuitive concepts at the foundation of quantum mechanics is quantum uncertainty - more technically called Heisenberg uncertainty. It is a concept that the human mind seems to be inherently incapable of grasping; yet, it is simply true, it is law of Nature. When an atom slows down enough, one starts seeing its size spread with slower speeds... the screwy thing about this is the following: by "size spreading" we mean its location becomes uncertain; uncertain not simply because our measuring instrument is not precise enough, but uncertain at its core, in reality, to Nature itself... the atom is really nowhere precise in particular, but anywhere in a region all at the same time. You can study quantum mechanics for decades, and this phenomenon stays difficult to chew on and remains always disturbing. But it is simply true. One has to accept that there is inherent uncertainty or "fuzz" in Nature. The picture with this post shows a recent actual snapshot of the surface of a piece of copper by a scanning tunneling microscope at IBM. 48 atoms are arranged in a circle; within the circle, a few electrons are trapped. The water like ripples you see are the electrons... a peak in a ripple indicates high likelihood for the presence of electrons, a dip low likelihood. And that is all that Nature itself can tell about the electrons in the circle; the electrons' locations are literally nothing but a fuzz of probability, they are in many places at the same time with different likelihood - and the whole thing ripples like waves on the surface of an ocean... perhaps somewhat romantic but still very very disturbing. In recent years, and in the context of string theory, this concept of uncertainty seems to extend to space itself... there are indications that if you look at empty space at very very (very) small distances, you would expect that the concept of location or point in space gets fuzzed out as well... you simply cannot zoom into the fabric of space beyond a certain limit. If you try, you instead find yourself zooming out instead of zooming in...

Monday
Sep272010

Seeing the quantum world

Seeing the quantum world with your own eyes... When you cool down water to make ice, water undergoes a so-called phase transition: its microscopic constituents, molecules, rearrange themselves drastically at a critical temperature, and the result is macroscopically dramatic - liquid to solid transformation. The microscopy lives in the crazy world of quantum mechanics, yet the effect pervades dramatically to large distances. This phenomenon of phase transition can be extremely shocking when the underlying quantum effects are really pushed to the limit... superconductivity is a phase of matter where quantum mechanics jumps from the microscopy and slaps you in the face. It is a beautiful manifestation of balance in Nature at extreme small distances and low temperatures. Before posting more about this elegant microscopic mechanics, check out this cool video about the phenomenon:

Sunday
Sep262010

Is this the face of God?

Is this the face of God? At least this is how this image was portrayed in the media when it was announced in 2000, described by some as the greatest scientific discovery in human history. The discovery process took roughly from 1965 to 2000, until physicists were finally able to pin down the details. The story goes as follows: About 14 billion years ago, the universe was at some point a small spec of hot opaque plasma plus dark energy (see my previous post about the dark side...). Because of the dark energy, space expanded violently and the plasma cooled down. At around 100,000 years since this initial explosion, the plasma condensed and became transparent, like milk turning into water. This image is an actual real picture of that moment of condensation, the deepest in space and time we are able to look. It is simply the closest we can get to imaging the beginning of time... The colors indicate temperature of the plasma, blue for colder, red for hotter. Every tiny temperature fluctuation ends up seeding stars and galaxies in the next 14 billion years as the transparent universe continues to expand. And here we are, miserable but a bit more enlightened.

Saturday
Sep252010

The Dark Side Of Things

In recent years, astrophysicists (who were ridiculed for decades for good reasons...) have finally pinned down the most amazing fact about the universe: the stuff we and the stars are made of and that we can see all around us is a tiny fraction of what the whole universe is really made of... about 95% of the universe is built from an unknown type of "stuff" that we cannot see. If that is not freaky enough, most of this dark stuff, about 70% of the whole mass of the universe, is something totally beyond our grasp: it antigravitates, repels... This dark stuff is everywhere around us, and because of it, the universe is undergoing a violent explosive expansion. Lots of cool stuff to write about this that we now know; for now, check out this video: a bit sensationalist, but the content is basically correct:

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