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Reality of Double-Slit Experiment

More than two hundred years have passed since Thomas Young performed the famous double-slit experiment as a demonstration of the wave behavior of visible light, and still its revelation has puzzled our sanity ever since. In short, if we shoot a beam of light at a panel with two small slits (less than a millimeter apart), the photons—elementary particles that light is made of—have to figure out how to get through the slits to radiate out the other side. If they were truly particles, like in the macro world, they would project a solid image of two piles on the background wall behind the slits. If they travel similarly to the waves, like water does in the macro world, the image would resemble a wave-like interference pattern: alternating locations, equidistantly spaced, where particles leave a mark on the wall.

Thanks to the outcome of the experiment, we know that light is capable of doing both. It always travels in a wavelike fashion, even if we shoot photons in a row towards slits, one after another. The quantum mechanics explanation is that photons are in superposition, meaning they can exist in different states and even multiple places at the same time. The weirdness comes 'only' if we try to tag particles with pass-through detectors in order to detect which slit they are choosing to go through. At that instant, they break superposition and continue to travel as macro-objects, just like bullets.


This is very similar to the coin flipping or well-known Schrödinger's cat from the macroworld analogy. If we use quantum terminology, these two are in a simple binary superposition; they both have only two outcomes, the coin ending either head or tail or the cat's version being either dead or alive. Superposition in a double-slit experiment is way more complex as far as the photons being in multiple places at the same time between the slits and the detection wall.

However, the weirdness is only present at the quantum level of the microworld, and in the case of light in the double-slit phenomenon, the puzzle is not the nature of how light travels but rather why it behaves the way it does in the moment of being observed. Certainly, it creates profound questions for which we still have no definite answers. The most interesting one is, did we find the puzzle here that shows us how nature really works? What is the reality behind the engine in the quantum world? More important is even the question: is this reality objective throughout the universe, or is it subjective and created for the observer only?


Let's think about the reality problem for the moment first. This behavior of breaking superposition for the sake of the observer is very reminiscent of graphically demanding video games in which the reality is never objective—the scenes are always rendered for the gamer's sensory inputs. If you play those kinds of games and decide to enter a closed room through the door, the room and everything in it don't exist at all until you open the door. Only then does the CPU start creating it for you, and there's a certain superposition of the room and your actions in it that breaks to only one outcome, depending on what you do.

Now, double-slit is too complex to test it this way, but binary superposition could be simple enough to create in the lab in quantum equivalent and monitor what happens. This is what the experiment made by Massimiliano Proietti and his team at Heriot-Watt University in Edinburgh tried to perform on a small-scale quantum computer made up of three pairs of entangled photons. The idea is to experimentally test Wigner's thought experiment of an observer of the quantum outcome being also observed by a second observer. The resulting statements of the two observers are that their interpretations of the outcome contradict each other. The same happens in the lab, with entangled photons in the role of non-conscious observers—the inequality in the data is definitely violated, which points in the direction that quantum mechanics might indeed be incompatible with the assumption of objective facts. To put it simply, multiple observers of the same event can have different outcomes as the process in superposition breaks in different patterns. Just like in video games, the reality of nature could also be subjective and rendered for the observer's eyes only.


Of course this raises more questions, and the main one is what "observation" and "observer" really mean. In quantum mechanics, an observation is defined as the interaction of two quantum states that can collapse each other’s probability wave function. In one way or another, this also means that by observing something, we disturb it to the point of ruining the process we are trying to understand. If we add a philosophical point of view, we can also ask ourselves, does consciousness play a role in the observation process? There's an interesting philosophical thought experiment starting with the question, "If a tree falls in a forest and no one is around to hear it, does it make a sound?" followed by "Can something exist without being perceived by consciousness?"

Well, if you ask me, consciousness or not, if we go this path with reflection to the original double-slit experiment, it is all going toward the direction that the unobserved world only exists in a sort of superposition state, all possibilities of all possible outcomes only waiting for an observer to disrupt it to the point of the ultimate collapse as the result of the reaction between the two processes and the observer. The light is no different; its wave-like behavior is its own superposition, only waiting for somebody to play with. Preferably with lasers and Lego cubes, just like in the above YouTube video. Science is fun, perhaps because it is so mysterious from occasion to occasion. I know I had tons of fun creating this video with my son a couple of years ago. Please find more stories within the physics thread of the blog in the below link.

Strange world of physics at MPJ:
https://www.mpj.one/search/label/physics

Science refs:
https://www.youtube.com/watch?v=h75DGO3GrF4
https://en.wikipedia.org/wiki/Wigner%27s_friend
https://phys.org/news/2019-11-quantum-physics-reality-doesnt.html
https://arxiv.org/abs/1902.05080
 

Is Infinity Real?

Sooner or later, computation hardware and artificial intelligence algorithms will inevitably reach the point of enough sophistication that the creation of a simulation of enormous proportions, for example, the size of the entire universe, will be effortless. So to speak. These god-like engineers of such future simulation will indeed face a decision point regarding which degree of limitation to create for their simulated entities or artificial intelligence units in order for them to never reach the point of finding the proof that their world is in fact nothing more than just a series of electrical or optical currents of one inconceivably powerful futuristic computer.

If created right, there's no doubt that the inner world of all those hypothetical units would seem to be as real to them as our own very reality is to us. So, considering the state of obvious, the question arises by itself: if our own reality is such a simulation and we are nothing but AI units within some alien quantum computer, what exactly is the limitation?


To me, it always has been infinity. My own limited mind always struggled with understanding what it really meant. Aristotle, who buzzed his head with infinity quite a lot, concluded that infinity is only potential in nature. We can always add a number to any number to the point of infinity or divide something into infinite parts, but in reality, he thought that it was impossible to exceed every definite magnitude for the simple reason that if it were possible, there would be something bigger than the heavens or something smaller than the atoms (Greek origin: άτομο, which means without volume and uncuttable).

Today we still can't find the proof of bigger or smaller volumes than we can see or understand. If we look up toward the heavens, we are pretty sure that we cannot see beyond the Big Bang or 14 billion light years in all directions due to the limitation of light speed. The same goes with understanding the smaller volumes of microcosm for which we think the current boundary is around the scale of 10e-12 Picometres due to the quantum limitation of observable micro space without disturbance by the observer.


All things considered, as proposed by mathematics, infinity might be just the other word for really, really big, or extremely small, or very old, or too far away. In every way, simply put, infinity might be just beyond our reach. Perhaps if we are really living in the simulation, this is our limitation, and we are pretty much designed in the realm of simulated physics to never reach it and to never learn what is behind the horizon. Ironically, the ultimate truth could be that there was nothing there. It might be where simulation ends and where alien software developers' backdoor is located. Their own reality could be entirely and unimaginably different.

But what if we are not living in a simulation? What if all the laws of physics were not invented by an ingenious developer and were instead real, perfectly natural, and not artificial in origin? Would we have a volume larger than heavens or smaller than quarks and strings? Or just maybe these two extremes are somehow connected and twisted in a loop with no need for infinity at all? Perhaps, ultimately, the size could be irrelevant and not a factor in all cosmic equations.
 
1 +  = ?

http://sten.astronomycafe.net/is-infinity-real/
https://en.wikipedia.org/wiki/Infinity
 

Unthinkable Solutions of Fermi's Paradox

"At some point, the gluons will no longer be able to hold the quarks together, and the hadrons will decay. Which will mean the end of matter in this universe." - Albert Einstein 1

As it seems, in our universe, nothing is made to last. Eventually, everything gets old and dies or changes or decays into something else, and I am not referring to the life forms only but to all matter in the cosmos. For all we know, this might not be true within our own macroworld alone, but also deep below, the same goes for particles in the quantum realm as well. The fact is that everything in the universe has a tendency to achieve the lowest energy state and to finally rest within a stable system, even if that means going through various changes or decays. In the quantum world, this could be true for the Higgs field as well. According to Hawking, if it becomes metastable, the vacuum decay bubble will emerge and consume everything in order to eventually reach the lowest energy state possible. For Higgs field being everywhere in the universe, this would mean instantaneous collapse of the whole universe and it's own ultimate change into a new and ultimately alien environment with a completely new set of laws of physics in the aftermath that could not be as friendly to the living beings as they are today.


But relax, this is just a theory; it might be wrong; nothing like it happened in previous 13.8 billion years (or did it?) and the quote from the beginning is not really formulated by the famous physicist. Well, fictitious Einstein did say it in Phillip P. Peterson's 'Paradox', a remarkable piece of science fiction driven by this scientific premise, but still, it might be something he would say if he were still alive today.

'Paradox' is a relatively new novel series, so I am not going to spoil the content, but to really understand how vacuum decay relates to the well-known Fermi's paradox or to better understand aliens' actions towards Earth and other star systems throughout the universe, I'd warmly recommend the read. As a science fiction fan for years and decades, I could only say that I didn't stumble to the better science fiction in relation to concepts such as Dyson spheres, quantum mechanics, fusion engines, antimatter propulsion, warp drives, the creation of the Big Bang and inflationary space, virtual reality of enormous proportions, wormholes, travel, and communication... The list is going on, and I can only speculate what is inside the third book that has just been released (unfortunately, due to my illiteracy in German, I'll have to wait for the summer and its scheduled translation in English). Anyway, this was one of the rare book series with a sequel even more interesting than the first book, with perfectly connected endings in both of them.


The idea of vacuum decay behind Peterson novels for the solution of Fermi's paradox is indeed new in scientific background, but surely there is more logic we can think of and apply to the absence of aliens, and the idea, more than half a century old, is getting renewed attention in recent years. What I am referring to is the simulation theory and/or holographic principle. It is triggered by the very research of black holes and the information paradox, which states that physical information can be lost and swallowed by black holes despite quantum mechanics postulate that nothing, including information, can ever be lost, only transferred from one form to another. One of the solutions for the paradox I discussed a while ago with the question in the post title 'Are We Holograms?' answered Fermi's paradox perfectly.

However, to get back to science fiction, on several occasions in the past, I mentioned "The Thirteenth Floor", the movie that portrays so far the best story about a simulation of everything in existence. I don't know why, but I never read the backstory about this great film, and especially for this post, I went to check where the script came from in the first place and discovered that it was loosely based on the book called "Simulacron-3", written by Daniel F. Galouye way back in 1964. Needless to say, I downloaded the copy and liked it very, very much. Considering the year and the fact that it was written at the dawn of digital computers, the details and sophistication of the story were amazing. In relation to Fermi's paradox, if we are indeed living in a simulated world created by aliens themselves and we are all nothing more than just a bunch of artificial intelligence characters in the game, then the absence of other intelligent forms becomes clear. Or we will meet them when they become programmed and inserted in the simulation. Anytime now.


Next in line of the fictitious solution for Fermi's paradox on the first glance is not something that much unthinkable. But if we reason about communications over long distances in space, calling the ET and/or receiving a message from aliens from deep space is not as easy as we might think. By using our current technology, that is. The most obvious is the SETI project, which was founded half a century ago based on only monitoring electromagnetic radiation in search of ET broadcasts. After that, many years of looking for the signal from the above failed to find anything so far.

The most interesting and one of the first works of science fiction in this realm was Carl Sagan's 'Contact', in which aliens managed to receive the Earth's earliest TV broadcast 25 light years away, decoded it, and sent it back into SETI's antennas. Unfortunately, even though this looks much more plausible than vacuum decay or giant simulation, it really is not. Engineering and the science behind it are cruel. To broadcast anything at all in the electromagnetic spectrum, the signal must be focused and powerful enough to reach the destination without dissipation of the signal, to avoid the data being embedded in too much noise on the way, or to experience path loss while spreading out over long distances. Our EM broadcasts from Earth are meant for Earth only (or for the Moon on occasion or two in the past), and they are not powerful enough to reach even the closest stars without serious signal loss. To get weak transmissions like that, aliens around Vega might need solar system-wide antennas to detect UHF broadcasts from us. The same goes for SETI on Earth; it is unlikely we will ever get anything that is not narrow, focused, and aimed directly toward us. Nevertheless, ''Contact' will always stay on my physical and digital shelves for being one of the best science fiction films in the history of the genre.


At least for this post, the last and final obstacle with life forms swarming the vast space throughout the universe(s) is ... life itself and its potential limitations. Organic life based on carbon or something else exotic to us could be fragile and short in general. One small asteroid strikes the planet in the Goldilocks zone, and poof... everything dies and resets. Billions of years of evolution go into oblivion in a cosmic second. Even if major extinction events miraculously avoid the intelligent species, they might be destined to destroy themselves at the end of the path. Even more unthinkable scenarios we are still not aware of yet can pop into the equation. One of the obstacles could be that life could exist only in networked scenarios, or, to be precise, it could only work and evolve, more or less, in the form of a giant hive mind in relation to the mother planet. If that's true, there could be a limit in distance for a small number of individuals to leave their world, where they would ultimately lose connection to the hive and die. We never sent anyone or anything to live beyond moon orbit, so if this is true, the border of life could be anywhere beyond that.

I am not sure that Arthur C. Clarke had this in mind when he wrote 'Rendezvous with Rama' back then in 1973. Probably not. However, it was not far from common sense that in this unthinkable scenario, in order to sail toward the stars, the only way that could be done is to build enormous spaceships and giant cities that could carry everybody on the one-way journey. There are countless hazards for that kind of travel, and something along the way might happen to the people who originally populated Rama in the beginning. If we add to the story ultimate laws of physics and issues with limited speed of travel, vast distances between stars, and sparse sources when it comes to little things like food and fuel, 'the hive mind' problem could be another perfect solution to the paradox to consider.


But let's stop here with imagining all potential reasons why we still haven't met ET. If I would like only to spice it up with more unthinkable reasons, it would not be that hard. Just think about the "Zoo Hypothesis", in which we are created and observed by aliens in their science fair experiment, or the theory that we are the first intelligent civilization to emerge so far, or that there is 'The Great Filter' that limits intelligent life species from reaching the potential to dive into stars.

In the end, we could all be wrong. Evolution of species throughout the universe might not be headed toward stars at all. Perhaps we have to reset our minds and look elsewhere, no matter how strange it sounds.

1 Quote by Albert Einstein character from Phillip P. Peterson's Paradox novel series

 Novels:
http://raumvektor.de/paradox/
https://www.amazon.com/Contact-Carl-Sagan-ebook/
https://www.amazon.com/Rendezvous-Rama-Arthur-C-Clarke

Image refs:
https://www.syfy.com/syfywire/heres-how-universe-could-destroy-itself-horror-vacuum-decay
http://lcart3.narod.ru/image/fantasy/jim_burns/jim_burns_cylindrical_sea.jpg
http://starkovtattoo.spb.ru/titanfall-wallpapers

Refs:
http://www.bidstrup.com/seti.htm
https://briankoberlein.com/2015/02/19/e-t-phone-home/
https://www.computerhope.com/issues/ch000984.htm
https://en.wikipedia.org/wiki/Daniel_F._Galouye
https://medium.com/o-s/6-mind-bending-solutions-to-the-fermi-paradox
 

Quantum Weirdness

Rarely do I get a chance and a real opportunity to revive an old article from the past and to update it to fit better in the present day. Actually, the quantum weirdness is still where it was four years ago—science is not something that changes overnight, especially with quantum mechanics, so I am not going to update the post with any new physics or breakthroughs. Instead, what's new and what pushed me to repost today is one extraordinary novel in the field. The book that kept me from sleeping last weekend was "Quantum Space" by Douglas Phillips, and in short, it is by far one of the best titles I read this year. It is one of those true sci-fi stories that follows the real science and, in this case, the weirdness of the quantum world I wrote about in this post, and I would add it is one of those articles I enjoyed writing the most in the history of the blog. But, before a couple of my glimpses at the book itself, followed by my warm recommendation, and especially if you want to read it yourself, please continue reading about physics itself. This one definitely requires some knowledge to understand it fully, so let's start with some weirdness of our own macrophysics first.

It's very well known that the world we live in is driven by two sets of rules, or physical 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. For example, if we drop a book and a feather and let them both hit the floor separately, it is obvious that the book touches the floor first. However, if we put a feather ON the book and let them fall together, they will hit the carpet at the same time. Well, the book will still hit the carpet first, but if you try the experiment, you will know what I mean. This simple experiment was itching Galileo's mind centuries ago when he discovered one of the fundamental physics laws stating simply that the mass of the object has no influence on the speed of free falling. But we can ask ourselves next, why did the feather travel 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 feathers than with heavy books.


Was the book/feather experiment weird to you? I am sure it was at least a little weird if you were seeing it for the first time. We simply accept things for granted. What we cannot see, like the air and its little ingredients in the above experiment, we tend to exclude from our perception. If this was a little strange and intriguing, let's go further to the world of the 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 a diameter of 9mm or a little bigger. If you are an Olympic champion in shooting, you will, of course, need only two bullets, one for each hole. 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 don't even 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 at the same time. In fact, if we had three or more holes on the wall, one single electron would go through each one and, at the same time, use all possible paths toward the destination. Perhaps the best illustration of what happens in this experiment is presented by the "Stephen Hawking's Grand Design" documentary made by Discovery Channel.

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

However, this is just another interpretation of the famous double-slit experiment, and even though the first theories about the duality of particles/waves originated way back with Thomas Young and his scientific paper about the properties of light in 1799, perhaps the best-known theory was proposed by Richard Feynman during the forties of the 20th century. The 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 (as we call them today) and energy waves are more or less the same. Electrons are among them. In simple words, they are capable of traveling as particles (and acting as bullets in our giant world by traveling within the straight line from point A to point B) or avoiding 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 the quantum world directly, we still have no clue why and how subatomic particles choose to travel either as a wave or as a particle of the material world. For example, in a previous double-slit experiment, if we tried to add a 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 transforming into waves and started going through the holes like simple bullets, with many of them crashing into the 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 thin air, forming waves and materializing back after the wall. That skill would be something special in every magician's performance.

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

As you probably noticed, this post is part of the "Beth's Q&A" thread, and even though quantum mechanics is not directly mentioned in Beth's and my chats, it is simply not possible anymore to stay with the standard or particle model of mainstream physics and to look to the inner world only by researching its particle-type properties. Like with me and possibly with many scientists out here (and to be fair, I am not the scientist, just a modest observer), a set of laws responsible for the entire microscopic world seems to be "under construction" today more than ever. The idea for this post came to me a 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, let's check a little current terminology regarding atoms with all their parts, including quarks as the smallest items within. The word "átomos" originates from the Greek word ἄτομος, and it was made by Democritus, an ancient Greek philosopher who, around the year 450 BCE, formulated the first atomic theory, or the nature of matter we are made of. Translated from Greek, "atom" means something basic and uncuttable into smaller pieces. Almost two millennia passed since Democritus, and finally, in the year 1911, it was discovered that an atom, after all, is made of even smaller particles. Ever since then, we know that an atom is now made of a nucleus with a positive electric charge surrounded by a cloud of negatively charged electrons orbiting the nucleus. The smallest atom is the simplest isotope of hydrogen-1, with a nucleus of just one proton orbited by one electron. The 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 a cloud of 94 electrons in the orbit. For 50 years, protons, neutrons, and electrons were the tiniest particles known to the world. Then in the year 1968, the very year when I was born, experimental physicists at the Stanford Linear Accelerator Center confirmed the existence of 6 different types 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—the other four quarks are called Strange, Charm, Bottom, and Top. I wonder how exactly one of them behaved 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 a strong nuclear force, which is extremely hard to break. A proton is made of two up quarks and one down quark, while a neutron is a combination of two down quarks and one up quark. They orbit around each other and form an entity we call a particle. The 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 structures.

However, we have a pretty good idea what's inside. Strings. Now comes the part of real weirdness. Are you ready to dive into a rabbit hole? It will not lead you into Wonderland, but it is certainly one of the biggest scientific 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 the standard model, besides six quarks and an electron, there are more fundamental particles. There are two more particles with negative charges similar to electrons called 'muons' and 'tauons.' Compared 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 have 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. The photon is, for example, a carrier for electromagnetism; the strong force is carried by eight particles known as 'gluons'; the weak force uses three particles, the W+, the W-, and the Z; and finally, gravity is supposed to be taken care of 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 the graviton. All efforts to include gravity in the theory so far have failed due to difficulties in describing it on a great scale within quantum mechanics. Step by step, over the years, new theories arrived, tending to fill in the blank or to replace the 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. Strings can move and oscillate in different ways. If it oscillates a certain way, then its name is electron. If it oscillates some other way, we call it a photon, or a quark, or a neutrino, or... a graviton. In a nutshell, if string theory is correct, the entire universe is made of strings! However, the mathematical model of a string theory, such as M-theory, is far more complex than we can possibly imagine. Even though string theory can be seen as an extension to the standard model, its background is far more different than with the universe described by the particle model. Compared to the space-time continuum we live in as a four-dimensional universe described by the 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-spatial dimensions, but within the quantum world there are objects capable of spreading their existence and occupying up to 9 dimensions. Furthermore, the theory predicts that additional tiny dimensions can be curved in a 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 a little bit more, the effect could, for instance, be different oscillations of strings, which would result in slightly different properties of fundamental particles, and electrons could start behaving differently and start having different electric charges. This example is highly speculative, but the point is that with different shapes of dimensional systems, the 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 the form of M-theory is correct, he would do that by some almighty computer capable of curving dimensions. A combination of changes in the curvature of miniature 7 dimensions could be able to change, for example, the value of pi, and instead of being 3.14159265359..., it could be a different number. It is unknown what that would 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 look very different than in our universe. However, there is still no direct experimental evidence that string theory itself is the correct description of nature and the true 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 the 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. In the 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 a double-slit experiment, all particles during the 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 antimatter 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 the 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 a very well-known phenomenon that is experimentally confirmed in the form of virtual particles that arise from vacuum (particle-antiparticle pairs) and cancel 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 the form of Hawking radiation).

I am sure that 'M-theory' will stay just a theory for many more years to come, as proving the 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 the ability of two particles (or more) that usually originate from the 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 an experiment between the ISS and Earth in the form of a first wireless Quantum Communications Network and for the first time perform the connection between two points separated by more than 400 km.

D-Wave quantum computer

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

At the very end, let me continue the story with a few short notices about "Quantum Space", amazing science fiction by Douglas Phillips and his first novel in the series. If you read the entire post and didn't have much knowledge about the science itself, I am sure by now you are better prepared to read the book and enjoy it much more. Of course, Douglas did a pretty good job with his characters explaining the science as well, perhaps on a much better level than I did, so there are no worries about understanding the quantum mechanics to follow the book. Much of it is still the unproven theory, so it's harder to distinguish science from fiction anyway. Nevertheless, for the fiction as far-fetched as it is, and even though the theory is weird by its nature, I found it to be, well, believable is maybe not the right word, but definitely intriguing. I loved the idea of expanding the microdimension and the way of solving the Fermi paradox within the storyline. The characters and the writing are also great, so in all the effort to write spoilerless reviews, all I can say is that I will eagerly wait next year for the sequels.

Image ref:
https://futurism.com/brane-science-complex-notions-of-superstring-theory/

Quantum Space
http://douglasphillipsbooks.com/books

*Stephen Hawking's Grand Design: Action of Electrons
http://www.discoveryuk.com/web/stephen-hawkings-grand-design-action-of-electrons

** Quarked!
http://www.quarked.org/askmarks/answer24.html

*** Stephen Hawking and Leonard Mlodinov: The Grand Design
http://www.amazon.com/The-Grand-Design-Stephen-Hawking/dp/055338466X
http://www.amazon.com/Velika-zamisao-Stiven-Hoking/dp/4095178361 (serbian edition)

Refs:
http://www.wikihow.com/Calculate-Average-Velocity
http://pratthomeschool.blogspot.com/2010/10/geometry-lesson.html
http://www.superstringtheory.com/
http://www.nuclecu.unam.mx/~alberto/physics/string.html
http://www.zmescience.com/science/physics/physicists-quantum-photons-08092012/
http://www.zmescience.com/science/physics/quantum-entanglement-iss
http://www.discoveryuk.com/web/stephen-hawkings-grand-design/videos/
http://en.wikipedia.org/wiki/Double-slit_experiment
 

Fringe Dream of Virtual Particles

Last night I had a vividly strange science fiction dream. Like with most of my dreams, and dreams in general, I guess, it was hard to recall all the details in the morning, and this one was no exception, but in a nutshell, the scene started with me in some science lab, describing the idea of how to effectively make a tiny hole in the universe. It was pretty simple—I was using four Tesla coils, perfectly positioned in the corners of the large square with edges of about a couple of meters long and with two small, battery-sized metal plates positioned in the center of the square. The experiment was that at the precise moment, Tesla coils fired four filaments of thunder, reaching the center point exactly between two metal plates at the same time, initiating a process that in the end created a tiny breach in the universe that I was describing in the dream as a brane between dimensions and within the void between multiverses. Anyway, in the process, one plate goes from metallic through dark and eventually invisible, while the other started immediately to glow and emit light and other sorts of radiation.


I was explaining in my dream that the breach positioned one plate just outside of our universe while the other stood here. Most of the pairs of virtual particles that were popping between two plates all the time out of vacuum are torn apart by the invisible plate, making them real particles from that point and attracting one toward itself, while the second particle is always attracted by the other plate, creating radiation and the glow in the process. Very similar to the Hawking radiation emitting from the event horizon of the black hole. Even though those two plates were positioned very near to each other, after the Tesla coils did the job by breaching the universe, they stayed in different realms from that point, keeping a relatively close distance between them and finding new equilibrium even when the coils were shut down.

Our plate was then taken out of the square center, wrapped in the bigger case, and used as a battery that never drains. Or, to be precise, not until the invisible plate in the system that is always outside of our universe depletes itself by doing its job of separating the particles, but it was explained in the dream to be an extremely slow process that takes centuries, even if the battery is used to generate lots of power, like empowering entire city blocks.


I know, having a geeky or nerdy dream can be weird for most people, but it's not that we can choose what to dream, can we? It is surely a product of my daydreams, so to speak, and definitely an outcome from my daily interests in astrophysics by watching various documentaries and reading articles online. The novel-like storyline was definitely the consequence of all of my science fiction fascination in both movies and books, which I enjoy from time to time as well. In this very case, the background of the entire story from the last night and today's post is all about the most intriguing feature of the universe. The one that might change everything one day. Virtual particles. They are one of those scientific theories that has extraordinary potential for the future. If we find a way to capture and control them. Hopefully not by poking our universe with bolts of lightning. :-)

But seriously, and sci-fi aside, let's see why virtual particles are one of those quantum properties I think we still wait to understand fully. First of all, they are not really virtual per se; they differ from real particles only by their short existence in time. Aside from that, they can have some or even all properties of the real particles, including mass, but so far it is not really possible to observe virtual particles due to their short lives. However, in the subatomic world, virtual particles are often found in diagrams invented by Richard Feynman that revolutionized theoretical physics by their simplicity to explain what was really happening during the quantum events.


For example, take the Feynman diagram above. It shows how two electrons collide. The internal line is a virtual photon, which is in this case a representation of the excitation of the electromagnetic field caused by electrons and their interaction. We can observe both electrons, their velocities, and paths, but we are helpless to spot the virtual particle. In this very case, whether this virtual photon is really a particle, lasting only a tiny fraction of time during collision, which would give it the title of an actual mediator of the force, just like what its counterpart, the real photon, is, or it is used just as a calculation aid, it is not really certain, but in the end any particle, real or virtual, is only a representation of the excitations of the underlying quantum fields. However, even though they are called "virtual" because of their unobservability, and even though we can't see how they "look" and "act," in one experiment we are definitely able to observe what they do. Experiment proposed by Hendrick Casimir in 1948 and confirmed by Steven Lamoreaux in 1996. The experiment is probably responsible for my dream in the first place. The Casimir effect of the virtual particle-powered machine is just by using two metal plates positioned very near each other. But to understand the Casimir effect, we need to understand one simple thing. Timespace itself. I am not kidding. This is mandatory and a requirement for further reading. Easy. ;-)

Well, I am not pretending that I understand what really happens in the universe, but mainstream science of the current date says, and I am trying to paraphrase it, that all that is around us and within us and at any point in time is just one soup of various fields. Like the Higgs field I talked about once earlier on the blog. Or gravitational field. Or in this post's story and this particular case, electromagnetic field. Any field, by definition, is a region in space (and time?) that is affected by some force. At any point in the field. It also means that a field is a region in space that contains energy. Now, an electromagnetic field is not something that can occupy a certain part of space. It is literally everywhere. It is a fundamental field that is actually in the background of the entire universe and not just in places with matter. Everywhere. Even in the vacuum, where nothing tangible exists. Some places contain more energy than others, with a vacuum being a place with the electromagnetic field in its lowest energy state. Not zero. Now, keep with me; it gets interesting—let's compare this field with actual soup that is always boiling.


If you are looking at the surface of the boiling soup, you will see bubbles and fluid filaments all over the surface, but at some places they are heavier and more powerful, and at other places they are calmer and more peaceful, but always boiling and moving. If we were able to glimpse a closer look and magnify the surface to see it on an even smaller scale, we would see that the entire surface is in a chaotic state of constant wibbling, wabbling, wobbling, blooping, and bubbling*. The same is with electromagnetic fields. The stronger wabbles are what we identify as electromagnetic radiation that propagates forward (and in the case of our soup, outside the pot to the kitchen floor), while the tiny wibbles are just a short-lived emission of photons or failed radiation, if you will.

That tiny failed radiation is possible thanks to quantum mechanics that allows temporary violations of conservation of energy, so one smaller particle can become a pair of heavier particles, and in the case of a photon, it goes from changes of being a wave, a mediator particle with no mass, or a pair of heavier particles—a couple of electrons and positrons (or a pair of quarks and antiquarks with radiation of one gluon). What exactly it is and when it happens is dependent on the ongoing process and energy levels of the system, but in the case of the lowest energy state of vacuum, we know that heavier particles are popping all the time, and due to the uncertainty principle, those virtual particles always appear in pairs. They are borrowing the energy from the vacuum and immediately collide and annihilate themselves, repaying the energy in order not to violate the laws of thermodynamics. These streams of virtual particles "coming out of vacuum and diving back" are well-known quantum features known as quantum fluctuations of the electromagnetic field.


Now, those virtual particles popping out into short existence are coming pretty randomly—and in all possible wavelengths—which brings to "the surface" a vast amount of energy due to their short life, normally invisible to us. If we position two uncharged metal plates very near to each other (less than a micrometer), only those virtual particles whose wavelengths fit a whole number of times into the gap emerge between the plates, while outside, without limitations, all possible wavelengths are accounted for. The result is that energy density between the plates is way less than the energy density of the surrounding space, and immediately a tiny force appears and starts pulling the plates toward each other. This force is named the "Casimir force", and the entire system the "Casimir effect". On first glance, it doesn't look strange—the same effect can be made with two plates in water that, with small waves created by a sonic generator**, are pulling toward each other as well—but keep in mind that the actual Casimir experiment is performed in a vacuum with no single atom of matter between or outside the monitoring system, and the plates are uncharged. So the "only effort" we need to make is to put them very near to each other, and they will start moving. The force is tiny, though; for example, for the one-square-meter plates apart by just one micron, the force is 1.3 mN*** (the weight of 1 kg is about 10N). The force is stronger for bigger plates and with shorter distances in between.

However, one potential propulsion engine, built on the principles of the Casimir effect with even a tiny but constant push like this one, is comparable with ion engines that create thrust by accelerating ions with electricity. For example, in "Dawn", the spacecraft that recently arrived in the asteroid belt was propelled by three xenon-ion thrusters, each with a force of only 90 mN. Eventually, after more than 8 years of travel, it accumulated acceleration over the mission to more than 10 km/s (41,260 km/h), which is pretty fast for a tiny push (even though it used other means of acceleration like gravity boost while transiting Mars). It carried almost 400 kg of xenon for the ion thrust engine, but the potential Casimir engine of the future would need none of such a payload. Its propellant would be the very vacuum of spacetime and its pairs of virtual particles.


Of course, the real application would come with separating virtual particles like in my dream or what black holes seem to do**** on a daily basis. If there is a way to make virtual particles real, the millinewtons will instantly lose that 'milli' prefix and be equipped with one more powerful (perhaps 'kilo' or 'mega'), and that will be something extraordinary. Something that in science fiction has a cool acronym. ZPE. Zero Point Energy. Surely, we must find other means to deal with this than by creating tiny black holes to do the job for us, but thankfully, the quantum world is always full of surprises, and perhaps one day we will build a machine that is capable of taking the energy out of a vacuum safely and is small in size, relatively speaking. Perhaps another quantum effect will be helpful for this job, the one that uses interactions between hydrogen electrons and virtual particles called the Lamb shift. But that is a story for another time.

Image refs:
https://www.nasa.gov/mission_pages/dawn/main/index.html
http://www.livescience.com/50119-superconductors-physicists-gravity-particles.html
http://pics-about-space.com/black-hole-hawking-radiation-diagram?p=3

Refs:
http://math.ucr.edu/home/baez/physics/Quantum/virtual_particles.html
* https://www.youtube.com/watch?v=Kn5PMa5xRq4
https://en.wikipedia.org/wiki/Zero-energy_universe
https://briankoberlein.com/2015/03/06/nothing-but-net/
** https://www.youtube.com/watch?v=PS8Lbq2VYIk
https://www.scientificamerican.com/article/are-virtual-particles-rea/
http://physics.stackexchange.com/questions/147096/are-virtual-particles-tool
***http://math.ucr.edu/home/baez/physics/Quantum/casimir.html
https://en.wikipedia.org/wiki/Virtual_particle
****https://en.wikipedia.org/wiki/Hawking_radiation
 

Gravis Gravity by Gravitons

Don't take this title too seriously. It's wrong on multiple levels. Grammatically and scientifically. Nonetheless, it fits perfectly for this post. As for grammar amiss, I used the Latin root word 'Gravis', which means heavy, and it is actually the perfect adjective for gravity as we perceive it here on Earth. As for the scientific issue, the rest of the title might be all wrong. If we glimpse into the features of the three main natural forces of the universe, it is obvious that they work in more or less the same fashion—they use carriers or elementary particles to mediate the force through the force field. The photon is one of them, and it carries electromagnetism, while strong and weak forces in the nucleus, respectively, are mediated by gluons and W/Z bosons, and they are all confirmed in experiments. Gravitons are supposed to be the same thing as gravitational force, but they are never found and confirmed either directly or consequently. Ever since Einstein, we have had second thoughts about whether or not gravity is acting as a 'normal' force at all or if it is something entirely different.


Think about this: you are located in the spacecraft far in space outside of the big, heavy planets and stars and truly experience microgravity. You start the engine, and your fancy spaceboat starts accelerating with about 10 m/s, and each second increases the speed with 10 m/s more. Actually, the right number is 9.806 m/s per second, which is the measurable 1 g force of the planet Earth. In our thought experiment, a spacecraft that works in a fashion that always uses constant acceleration and half the journey from, i.e., Earth to Mars, pushes with 1g, and the other half turns around and uses backthrust with the same 1 g, could not only provide a normal human environment inside the craft, but it would also be very fast and reach the red planet in just three days*. If you can't imagine how this would be working in real space travel, I will only state the name of one fictional spaceship from the sci-fi literature. Its name is Rocinante**, and it is one great piece of interplanetary Corvette from the amazing franchise "The Expanse".

Well, science fiction aside, the point here is that gravity and acceleration seem to be one thing. The obvious conclusion in this chain of thoughts is that Earth and Rocinante are both capable of creating gravity of one steady g. At least it looks the same from the observer's point of view. However, we know for sure that Earth is round and rotates, and no matter where you are standing, it will pull you toward its center without accelerating anything. It's just enormously big and does something to the very fabric of spacetime itself, which is actually pulling you by invoking some mechanism we don't understand yet. Perhaps by using gravitons—our friendly force carriers from the title? Actually, both particle and string theories predict gravitons as real things. In the former case, it is a massless boson with spin-2, while in one of the string theories, it is sort of a closed string with a low-energy vibrational state. I will not go into further scientific details in both theories, but it is evident that a massless particle or low-energy string is very hard to observe, as it either never or extremely rarely interacts with other particles on subatomic levels. Let's compare it with neutrinos for a moment—an elementary particle with no charge and the tiniest mass we can detect. Their large, super-awesome underground detectors, like the Super-Kamiokande Neutrino Detector in Japan, detect only a handful of neutrino interactions with regular matter over a long period of time. For example, when light from the Big Kaboom from supernova SN1987A reached the Earth, Kamiokande detected the sum of only 19 neutrinos from this super explosion. And to use Carl Sagan terminology, there were billions and billions of neutrinos only from that event. Detection of a single graviton, even if we consider some theories that suggest gravitons with non-zero mass, would be extremely hard.


Ever since Einstein's general theory of relativity, scientists have been struggling to find the best description for gravity. If we are looking at it as a fourth natural fundamental force, compared to the other three, it is the weakest by far; for example, gravity is about 36 orders of magnitude weaker than electromagnetic force, and it probably has a trivial influence on subatomic particles. However, it is cumulative and always attractive and therefore plays the major role in the macroscopic realm, making it possible for planets to orbit their stars, and it is behind the recently experimentally confirmed gravitational waves by the LIGO (Laser Interferometer Gravitational-Wave Observatory) experiment. Einstein himself first noticed the difference in behavior of four fundamental forces and spoke of gravity as not a 'normal' force per se but more as a fictitious (or apparent) force that is observed only as a consequence of the curvature of spacetime caused by the presence of large masses or energy throughout the universe. A very nice example of one apparent force is the Coriolis force, or Coriolis effect. It is observed as a force, but in reality it is just an apparent deflection of an object that is moving in the spherical system, such as Earth, that rotates. Deflection is caused by the fact that the rotating speed of the Earth is faster for a moving object located near the Equator than for one near the pole. In simple words, the system you are moving in is also in its own motion that must be included when you want to calculate the actual path of yours; otherwise, you will never reach your intended target. And in the universe, everything is in motion. Gravity could be just that—an apparent force that is caused by the interaction of large moving masses with the fabric of the universe itself that might be in its own motion as well. Or perhaps gravity could be the outcome of the interactions of mass with the potential energy of that fabric itself. In science fiction and also in the quantum science realm, this is known as zero-point energy, quantum vacuum zero-point energy, or simply vacuum energy. If I understand this correctly, by applying Heisenberg's uncertainty principle (we can only know the position or velocity of a moving particle, but never both), every quantum system to sustain this principle must have minimum non-zero energy. In the case of a vacuum, this is the minimum energy of all fields in the universe, including the necessary Higgs field needed to provide the existence of every mass everywhere in the cosmos in the first place.

In the conclusion of the scientific part of this post, I am hoping that whether the future will confirm gravitons and 'pronounce' gravity as a real fundamental force or we finally find how big masses influence the tiny quantum world of the universe's fundamental ingredients, in the end we will have our answers, which might bring more challenges and questions for future generations. Maybe even ways of mastering it by applying some ingeniously clever engineering of future gravity-related devices and tools. Of course, how exactly the world would be changed with full understanding of gravity and gravity-based appliances; perhaps the best vision is in the science fiction of the amazing futuristic thriller "Influx", written by Daniel Suarez.


I am always eagerly acquiring novels with gravity premises in the background if the plot teaser is interesting enough, so I bought 'Influx' a while ago and stored it in my Kindle's queue for future reading. I was a little busy with my work and reading a couple of other novels, but now I have this regret of why I didn't read it sooner. It was really amazing! Just exactly as comprehensive and entertaining as I was hoping for when I saw the book cover in the first place. The science behind the gravity mirror or deflector invention in the book is perfect and just in the realm of sci-fi plausibility I am always looking for. It was explained perfectly well in both the science behind the invention and also in the workflow of all engineering vehicles, armor, satellites, and other appliances that were built on it. If you add to the main 'gravity' twist all 'regular' sci-fi inventions such as AIs, robots, cold fusion, quantum computers, futuristic weapons, immortality, and other non-sci-fi thriller stuff, please believe me that my additional regret after reading this book was that it had only 500+ pages. I wouldn't mind if Daniel added more stories to it and created a sequel. I read somewhere that FOX is interested in the movie, and hopefully this will see the daylight in the end. It perfectly fits for a motion picture, not just because of the science and story but also because of the potential artistic and visual aspect of gravitational falls in all directions that was extraordinary.

Image refs:
https://www.artstation.com/artist/deningart
http://www.thethoughtarchitects.com/2014/04/14/detecting-neutrinos-neil-degrasse-tyson/
http://www.thedaemon.com/

In-text refs:
* http://www.johndcook.com/blog/2012/08/30/flying-to-mars-in-three-days/
** http://expanse.wikia.com/wiki/Rocinante

Refs:
https://en.wikipedia.org/wiki/Graviton
http://www.japantimes.co.jp/news/2012/01/08/national/science-health/japans-super-k
http://rationalwiki.org/wiki/Zero-point_energy
http://abyss.uoregon.edu/~js/glossary/coriolis_effect.html
https://www.youtube.com/watch?v=i2mec3vgeaI
 

Chasing Ghosts of the Universe

You probably heard that matter is pretty much an empty space. It's true. Everything is made of tiny particles with nuclei in their centers and clouds of electrons orbiting around. If we take hydrogen (H), for example, the smallest atom with just one proton in the nucleus orbited by just one electron, and if we scale the proton to be the size of a basketball, the orbit of the electron in diameter would be something about 15 km. Both the nucleus and electrons are electromagnetically charged, keeping everything in stable equilibrium, and also inside the nucleus, two more fundamental forces—strong and weak nuclear interactions—are keeping all the matter and energy in line. However, the smallest atom in the universe is not the smallest standalone system we know of. According to the standard model, all atoms and complex molecules found in nature or artificially produced are made of fundamental particles. Something we cannot cut into smaller pieces. Electron is one of them. But there are more. So far, as far as we know, if we count all of those basic particles inside protons or neutrons and those that represent force carriers in addition to the "god" particle that makes all the mass possible, there are exactly 17 of them. But one of them deserves its own story to tell. Its nickname is "the ghost particle," and it is literally capable of passing through any mountain like it is made of cheese.


You probably guessed, this will be a short story about neutrinos, the most elusive particles in the universe we can play with. They are products of radioactive beta decay in heavy nuclei where a proton or neutron decays into other subatomic particles, i.e., if a proton decays in a process known as 'beta plus decay', it transforms into a neutron, a positron, and a neutrino. In the moment of its creation, even if it happens in the center of the sun, it escapes the entire star immediately. There are many different beta decay types, and I mentioned just one; others help as classified neutrinos. Just like with other fundamental particles that come in three flavors—the charged leptons (electron, muon, tau), the up-type quarks (up, charm, top), and the down-type quarks (down, strange, bottom), bottom)—neutrinos can also be different in mass and property. The one created in the previous example with the creation of positrons is called an electron neutrino, but if anti-tau or anti-muons are created in the process, neutrinos that emerge on the other side of the decay will be tau or muon neutrinos, respectively. A neutrino, no matter which type it is, belongs to leptons as well. This means it is not affected by strong nuclear force at all, and it only interacts with weak nuclear force, and because it is a particle with mass, it also follows gravity as well. To simply illustrate its ghostly manner, I will just note that its tiny mass is about 4 millionths of the electron mass (and electron mass is 1837 times less heavy than the entire mass of hydrogen). Furthermore, it is not electromagnetically charged and therefore not affected by this fundamental force as well. In other words, if you like to watch horror movies or believe in ghosts, the obvious conclusion is that they are made of neutrinos. That would perfectly explain how ghosts travel through walls and doors just like Patrick Swayze did in the movie "Ghost" a couple of decades ago.

Well, kidding aside, and thankfully for these neutrino features, they are really one ghostly particle that is extremely hard to either control or detect. However, this phantom behavior of theirs immediately triggers some extraordinary ideas. If we could embed messages into neutrinos and control the path of their beam, we might literally send them through anything. If some neutrino-based portable device is possible to be built and you are located, for example, in Buenos Aires, Argentina, and you want to send a message to Beijing, China, you would have to point your neutrino device slightly toward the center of the Earth*, and neutrinos would reach the receiver with the speed of light all the way through the planet. But before we glimpse into the obvious possibility of whether or not it is possible to use neutrinos in some sort of communication, let's check some more facts about them.


Basically, neutrinos, strictly speaking, belong to the radiation realm. They are indeed carriers of radioactive energy. The same as alpha and beta particles, gamma rays, muon radiations, and tons of other types of particles floating around the universe as a result of different types of particle decays or some other processes in the universe. Actually, we are living in a soup of radioactive energy on a daily basis from various sources, as pretty much everything in the universe is decaying or decomposing toward the ultimate fate of the universe, which will in the end be just one giant soup of basic ingredients, if the everlasting expansion of the universe is the correct theory, that is. Therefore, the choice between usage of paper and plastic bags has nothing green in the potential answer. Either way, both bags will eventually decompose. Just give them enough time. Humans are also radioactive; we also emit radioactive particles thanks to the radioactive food we are consuming. Technically speaking, all food is radioactive because all organic food contains carbon-14, or radiocarbon, as it is nicknamed. Many other radioactive elements can be found in other products, and the most notable one is potassium-40. This one is actually a radioactive isotope that undergoes all three types of beta decay. In one of them it emits neutrinos as well. So, if you like eating bananas, rest assured that you are one of the neutrino producers, as well as bananas are very rich in potassium. Believe it or not, large container shipments full of bananas at ports or airports regularly trigger radiation alarms. Well, if you have not eaten the entire container full of bananas, you are safe. Radiation from a couple of bananas is harmless, way below the edge, and potassium is actually very good for you, and if you emit a neutrino here and there, nobody will notice. Believe me. Well, on second thought, don't believe me. Even though neutrinos are very hard to detect, there is still, after all, a way to do it.

Neutrinos are tiny particles, but a few of them, on rare occasions, still collide with the atom nucleus of the material they are passing through. And by few, I mean the literal meaning of the word. The Sun is producing an extremely large number of neutrinos—60 billion per square centimeter are passing through Earth and... us each second. That is maybe around 100 trillionneutrinos passing average humans. To detect that few, several extremely large detectors are created, and one of them is shown in the above image: Super-Kamiokande under Mount Ikeno in Japan. It utilizes Cherenkov radiation, optically equivalent to a sonic boom, to detect collisions. If a neutrino collides with the electron or nuclei of water, the neutrino only changes direction, but the particle that was struck recoils in sudden motion and faster than the speed of light in water (which is slower than the maximum speed of light in a vacuum). This creates a flash of light, which is amplified with photodetectors (those round bulbs all over the water pool). This flash provides information on the direction and type of the neutrino. SK is located in the old zinc mine 1 km below the surface in order to exclude all other radiation from reaching the water and ensure that only neutrinos are detected. To illustrate the small number of neutrinos detected with this approach, state the fact that the total number of collisions detected from supernova SN1987A in Kamiokande was only 19 out of trillions of neutrinos emitted by the supernova. A small number of neutrinos are regularly detected from the Sun, and their number is way smaller than predicted by the number of estimated nuclear reactions in the star, which provides proof that neutrinos are able to change their flavor during their travel, and as it seems, especially during their travel through solid matter. Different numbers of solar neutrinos are detected during the night as they pass a long way through the solid matter of the entire planet Earth, while during daylight they need to penetrate only those 1000 meters to reach the mine chamber.


Poor detection of neutrinos due to their weak interaction with matter is only the start of bad news regarding the potential communication device we are trying to build. More difficulties follow. For example, artificial production of desirable types of neutrinos is either with nuclear reactions or in particle accelerators, which are either too large or too dangerous to build. Encoded information in beamed neutrinos can also be lost with their oscillation between flavors during travel. Creating desirable beams and paths is still not perfect, and last but not least, there is too much noise on the way, as billions and billions of other neutrinos are also there, either created in stars, supernovas, or those created in the very beginning during the Big Bang. Even so, scientists with powerful proton accelerators developed a procedure to develop stable beams of neutrinos or anti-neutrinos**, which are then directed toward near and/or distant detectors. Two experiments emerged with potential scientific value: in the first, a neutrino beam at Fermilab was sent with a short, encoded message through 240 meters of rock toward the MINERvA neutrino detector, and the word "neutrino", which was binary encoded within the beam sequence, was successfully decoded. The second and most challenging one was performed in Japan. Within the "T2K experiment", both neutrino and anti-neutrino beams are created in the J-PARC laboratory and sent toward the 295 km distant Super-Kamiokande. Both are successfully detected and, in return, opened the first working neutrino beamline over large distances.

So in both theory and practice, neutrino communication might be possible, and current experiments confirm it with working proof of concepts made in large neutrino observatories and accelerators. Actually, it resembles the state of computers as they were some half a century ago, when they were large and limited in mathematical computation and built with bulky vacuum tubes. With the invention of semiconductors and transistors, everything changed, and the result is pretty much in front of you, either on your desk, lap, or palm. Perhaps a similar breakthrough is waiting to be invented so we could equip our smartphones of the future with neutrino messaging when we would be finally able to send texts to Mars from our living room without enormous satellite dishes. Who knows, maybe the search for extraterrestrials would gain a completely new angle, and perhaps many of those neutrinos that are passing through our bodies right now could be complex messages from E.T., and neutrino communication in the future might be our ticket into the Milky Way alien internet. Universe's WiFi. So to speak.


Speaking about E.T. and science fiction in general, this neutrino story reminded me about two more things I love to share in conclusion for this post. The first one is John Cramer, an experimental and theoretical physicist and professor at the Department of Physics, University of Washington, Seattle. Some seven or eight years ago, Cramer intended to perform an experiment with two quantum entangled laser beams pointed in different directions. He was trying to prove that by fiddling with one beam that was sent into a circuitous detour miles away through optical cable, it would be detectable on the second beam that ended in a detector much earlier in a different location. Detection of this form of laser beam fiddling would be an indication that quantum entanglement is a phenomenon not only between spatially distant particles but also distant in time. When asked what he expects in the outcome, John Cramer, being a science fiction author as well, said, "If this experiment we're doing works, then I will follow up and push it as hard as possible. And if it doesn't work, I will write a science-fiction novel where it does work. It's a win-win situation."

The second thing, and in the recent tradition of MPJ and its "books" thread, what partially hinted at this post is the great novel "Signal", written by Patrick Lee, with the entire plot triggered by the neutrino-based portable device capable of catching radio waves from the future by harvesting neutrinos that move against the direction of time. The device is able to hook into radio stations 10 hours ahead. Just try to imagine all the implications and applications of this kind of fictitious device. If you can't, I am encouraging you to grab Patrick's novel and read it. I literally swallowed it and, during reading, eagerly waited for another chapter. I really can't emphasize what is better, the thriller plot, the sci-fi, or the intense writing. I will say no more.

Image refs:
http://motherboard.vice.com/read/why-neutrino-detectors-look-so-cool
http://irfu.cea.fr/Sphn/Phocea/Vie_des_labos/Ast/
http://www.patrickleefiction.com/
http://www.nuclear-power.net/nuclear-power/fundamental-particles/antineutrino/
http://particleadventure.org/neutrinos.html

In text refs:
* http://www.antipodesmap.com/
** http://www.symmetrymagazine.org/article/november-2012/how-to-make-a-neutrino-beam

Refs:
http://physics.info/standard/practice.shtml
http://chemistry.about.com/od/foodcookingchemistry/tp/Radioactive-Foods.htm
http://discovermagazine.com/2007/jun/life-is-rad
http://www2.lbl.gov/abc/wallchart/chapters/03/2.html
https://profmattstrassler.com/articles-and-posts/particle-physics-basics/neutrinos/neutrino-types/
http://timeblimp.com/?page_id=1033
http://cosmiclog.nbcnews.com/_news/2007/07/17/4350992-backward-research-goes-forward
http://faculty.washington.edu/jcramer/cramer.html