Quantum Weirdness

It's very well known that the world we live in are driven by two sets of rules or physic laws. The one for big and the one for small. We don't need to be rocket scientists in order to observe our big world surrounding us and to notice all the laws we obey to. For example if we drop a book and a feather and let them both hit the floor separately, it is obvious that book touches the floor first. However if we put feather on the book and let them fall together, they will hit the carpet in the same time. This simple experiment was itching Galileo's mind centuries ago when he discovered one of the fundamental physics law stating simply that mass of the object has no influence to the speed of free falling. But, we can ask ourselves next, why the feather traveled slower toward the floor if dropped alone? Because of the things we cannot see. The air is blocking it. To learn what is happening with the feather during the fall we have to go beyond our eyes. We need science and experiments to discover why small molecules of the air would rather play with feather than with heavy book.

Feather experiment on the Moon, by Apollo 15's commander David Scott

Was the book/feather experiment weird to you? I am sure it was at least little weird if you are seeing it for the first time. We simply accept things for granted. What we cannot see, like the air and its little ingredients in above experiment, we tend to exclude from our perception. If this was little strange and intriguing, lets go further to the world of even smaller and compare it to the world of the big. For example, in a mind experiment, we have a 9mm gun and shoot toward the wall with two holes in it, both with diameter of 9mm or little bigger. If you are Olympic champion in shooting you would of course need only two bullets, one for each whole. In the world of little if we use a gun that shoots electrons toward a wall with two adequate holes in it, you would probably think that we would need two electrons to hit both holes, right? Nope, we need only one. Believe it or not, one electron goes through both holes and we even don't need to aim too perfectly. No, it doesn't split up in two and use each half to pass the holes. It goes through both holes in the same time. In fact, if we had three or more holes on the wall, one single electron would go through each one and in same time use all possible paths toward the destination. Perhaps the best illustration what happens in this experiment is presented by "Stephen Hawking's Grand Design" documentary made by Discovery Channel.

And you thought feather on the book was weird...

However, this is just another interpretation of the famous double slit experiment, and even though first theories about duality of particles/waves originated way back to Thomas Young and the year of 1799 with his scientific paper about properties of light, perhaps the best known theory was proposed by Richard Feynman during forties of 20th century. Beginning of the last century will be remembered by the birth of quantum mechanics, part of the physics trying to describe all the laws responsible for what is happening in the inner world or the world where the very fabric of our universe is located. Feynman confirmed Young's light theory that subatomic particles (how we call them today) and energy waves are more or less the same. Electrons are among them. In simple words, they are capable to travel as particles (and acts as bullets in our giant world by traveling within the straight line from point A to point B) or to avoid obstacles by transforming into waves and vice versa. However, after all these years, due to the fact that we are way too big to monitor quantum world directly, we still have no clues why and how subatomic particles choose to travel either as a wave or as a particle of material world. For example, in previous double slit experiment, if we tried to add source of photons, and "light" the holes where electrons are "passing through", trying to find out what happens on the surface of the wall and how they "choose" to be either particles or waves, we only added disturbance in the system and electrons simply stopped to transform into waves and started going through the holes like simple bullets with many of them crashing into wall in case of missing the holes. It's almost like they know that somebody is watching them and that they don't like to expose their secret of how they vanish into tin air forming waves and materializing back after the wall. That skill would be something special in every magician performance.

As you probably noticed, this post is titled with "Beth's Q&A" prefix and even though quantum mechanics is not directly mentioned in Beth's and my chats, it is simply not possible any more to stay with standard or particle model of the mainstream physics and look to the inner world only by researching it's particle type of properties. Like with me and possibly with many scientists out here (and to be fairly added, I am not the scientist, just modest observer), set of laws responsible for entire microscopic world seems to be "under construction" today more than ever. The idea for this post came to me couple of months ago, when Beth asked me exactly this: "Somewhere, sometime, someone figured out the inside of the atom. Quarks they call them. What we used to call the proton and nucleus of the atom. Why can't we still call them as before. Why did a new name come into play? Who discovered quarks, and how. Did they use the electron microscope? Did they use math? Tell me what you know of quarks. How did that come about? I am interested in the electron microscope and quarks or anything else hiding in an atom. The item that was never to be broken down as it was taught to me".

Quarked! - How did the quarks get their names?**

Before we dive into more weirdness of the quantum world, lets check a little current terminology regarding atoms with all its parts including quarks as the smallest items within. The word "átomos" originates from the Greek word ἄτομος and it was made by Democritus, Ancient Greek philosopher who, around the year of 450BCE, formulated first atomic theory or the nature of matter we are made off. Translated from Greek, "atom" means something basic and uncuttable to smaller pieces. Almost two millenniums passed since Democritus and finally in the year of 1911 it was discovered that atom, after all, is made of even smaller particles. Ever since then, we know that atom is now made of nucleus, with positive electric charge surrounded by the cloud of negatively charged electrons orbiting the nucleus. The smallest atom is the simplest isotope of Hydrogen-1 with nucleus of just one proton orbiting by one electron. The most heaviest atom made by nature found on Earth is Plutonium-244, the most stable isotope of Plutonium with 94 protons and 150 neutrons in its nucleus and with cloud of 94 electrons in the orbit. For 50 years protons, neutrons and electrons were the tiniest particles known to world. Then in the year of 1968, the very year when I was born, experimental physicists at the Stanford Linear Accelerator Center confirmed existence of 6 different type of quarks. Much like electrons, they have various intrinsic properties, including electric charge, color charge, mass, and spin. Two of them with the lowest mass are the most stable and they are simply called Up and Down. Scientists are not very intuitive when it comes to naming stuff - other four quarks are called Strange, Charm, Bottom, and Top. I wonder how exactly behaved one of them in accelerator's results in order to get the name 'Charm'. On the other end, I like this much more than naming scientific stuff with only Greek letters. Anyway, within the standard model of particle physics quarks are building blocks in the universe and many particles are made out of quarks. Quarks can't live in solitude, only in combination with other quarks and they are tied up with strong nuclear force which is extremely hard to break. Proton is made of two Ups and one Down quark, while neutron is combination of two Downs and one Up quark. They orbit around each other and form an entity we call particle. Bottom line now is that, as far as we know, quarks and electrons are fundamental particles and we don't have any proof that they are made out of even smaller internal structure.

However, we have pretty good idea what's inside. Strings. Now comes the part of real weirdness. Are you ready to dive into rabbit hole? It will not lead you in the Wonderland, but it is certainly one of scientific biggest adventures.

Stephen Hawking, Grand Design***

Actually, it's not easy to describe what strings are in scientifically popular terms, but I will try anyway. In standard model besides six quarks and electron there are more fundamental particles. There are two more particles with negative charge similar to electron called 'muon' and 'tauon'. Comparing to electrons they are much heavier in size (if we can speak about size when it comes to fundamental particles). Finally, there are three types of neutrinos or particles that are neutral in electric charge. So far we encountered 12 fundamental particles. But there are more. As far as we know today, there are four fundamental forces as well (gravity, electromagnetism, and the weak and strong nuclear forces) and each force is produced by fundamental particles that act as carriers of the force. Photon is for example carrier for electromagnetism, the strong force is carried by eight particles known as 'gluons', weak force is using three particles, the W+, the W- , and the Z and finally gravity suppose to be taken care by the fundamental particle called 'graviton'. Standard model predicted existence of all these fundamental particles, including Higgs boson we talked about last year in post Beth's Q&A - The God Particle. Each one except for graviton. All efforts to include gravity in the theory so far failed due to difficulties to describe it on a great scale within quantum mechanics. Step by step, over the years, new theories arrived tending to fill the blank or to replace standard model entirely. There are several string theories that are 'under development' with the best candidate called 'M-theory' formulated in the last decade of the last century. In short, strings are single-dimensional objects we find within fundamental particles or to be precise, particles are nothing more than just different manifestations of the string. String can move and oscillate in different ways. If it oscillates a certain way then it's name is electron. If it oscillates some other way, we call it a photon, or a quark, or a neutrino or ... graviton. In the nutshell, if string theory is correct, the entire universe is made of strings! However, mathematical model of a string theory, such as M-theory is far more complex we can possibly imagine. Even though string theory can be seen as an extension to the standard model, it's background is far more different than with the universe described by particle model. Comparing to the space-time continuum we live in as four dimensional universe described by standard model, in M-theory there are 7 dimensions more. Those dimensions are tiny and undetectable by big objects like us living in large three spacial dimensions, but within quantum world there are objects capable to spread its existence and occupy up to 9 dimensions. Furthermore, the theory predicts that additional tiny dimensions can be curved with large number of ways and even a slightly different position or curvature of at least one dimension would lead to dramatic changes of the whole system or entire universe. For example if somehow we forced one dimension to curve little bit more, the effect could for instance be different osculations of strings which would result in slightly different properties of fundamental particles and electrons could start behaving differently and start having different electric charge. This example is highly speculative, but the point is that with different shape of dimensional system, set of physical laws in the system would be completely different.

To put it simply, if laws of the universe can be changed by, for example, God and if string theory in form of M-theory is correct, he would do that by some almighty computer capable of curving dimensions. Combination of changes in curvature of miniature 7 dimensions could be able to change for example value of pi and instead of being 3.14159265359... it could be different number. It is unknown what would that mean further but in the universe where pi is for example 5, the circle would be something entirely different and the pupils in schools learning about it would probably looking very differently than in our universe. However, there is still no direct experimental evidence that string theory itself is the correct description of nature and truly theory of everything most scientists dream of.

Completing superstring theory

But if laws of the universe after creation are unchangeable (not even by the gods) and if M-theory is true, is it possible that some natural phenomenon exists out there capable of giving birth to different universes by randomly producing shape of their inner cosmos? Yep, there is one. Appropriately called "The Big Bang". The moment of creation of everything we are familiar with, including time. First couple of moments, when the process was very young, we can safely say that it all worked completely under the quantum mechanics and laws of the microcosmos and it is not far from common sense to expect that, like in double slit experiment, all particles during first moments of their existence used all possible paths in their travel toward the final destination. Within M-theory this might mean that all possible versions of universes emerged as the result and the one we exist in is just one of many. Furthermore, theory also predicts that within one universe all positive energy (planets, stars, life, matter and anti-matter in general) is balanced by the negative energy stored in the gravitational attraction that exists between all the positive-energy particles. If this is correct then total energy within one universe might be zero and therefore possible to be created out of nothing only by quantum fluctuations of the primordial singularity. Quantum fluctuations are very well known phenomenon which is experimentally confirmed in form of virtual particles that arise from vacuum (particle - antiparticle pairs) and cancels each other almost immediately (unless this happens on the event horizon of a black hole where one of the particles was immediately captured by the black hole leaving the other alive in form of Hawking radiation).

I am sure that 'M-theory' will stay just a theory for many more years to come as proving existence of strings, multi-dimensions, multi-universes, supersymmetry, etc. must be very hard with our current technology but theories improve over time as well as technology and perhaps we will have our answer relatively soon. However, the quantum world with all its weirdness is very much real and many predictions no matter how strange are already proven. For example, quantum entanglement on top of it. This is ability of two particles (or more), that usually originates from same source, to have the same properties like momentum, spin, polarization, etc. so that even after they are separated in space, when an action is performed on one particle, the other particle responds immediately. This was experimentally confirmed with two photons separated by 143 kilometers, across two Canary islands and soon should be used in experiment between ISS and Earth in a form of first wireless Quantum Communications Network and for the first time perform the connection between two points separated by more than 400km.

D-Wave quantum computer

Finally, let's just mention one potential application of quantum superposition (ability of a particle to exists partly in all its particular theoretically possible states simultaneously). Comparing to digital computer where one bit can hold information in form of either 0 or 1, one qubit (quantum computer alternative) can hold either 0, 1 or anything in between and in same time. The idea is to use this property and build a quantum computer capable of performing millions of operations in the same time. Still being in early years of development and far before commercial use, quantum computers with up to 512-qubits developed in D-Wave, one of the leading company dedicated for future quantum computers market, are made based on chip specially manufactured for quantum computation. Maybe it is still too early to say but I have a feeling that quantum mechanics is matured enough and ready for practical applications, especially in the field of communications and IT. Along with nano-technology, this would some day in near future be one of those truly breakthrough discoveries capable of changing the world entirely.

Image ref:

*Stephen Hawking's Grand Design: Action of Electrons

** Quarked!

*** Stephen Hawking and Leonard Mlodinov: The Grand Design
http://www.amazon.com/Velika-zamisao-Stiven-Hoking/dp/4095178361 (serbian edition)


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