10 Science Facts

[Mordred]

Today's theme: Quantum Mechanics: #2 Quantum phenomena

1. Quantum superposition is a fundamental principle of quantum mechanics that holds that a physical system—such as an electron—exists partly in all its particular, theoretically possible states (or, configuration of its properties) simultaneously. However, when measured or observed, the electron gives a result corresponding to only one of the possible configurations

2. The most famous and the first experiment related to quantum superposition is offered to us by Erwin Schrödinger in his "thought" experiment: Schrödinger's Cat. Although the original "experiment" was imaginary, similar principles have been researched and used in practical applications. The thought experiment is also often featured in theoretical discussions of the interpretations of quantum mechanics. In the course of developing this experiment, Schrödinger coined the term verschränkung (entanglement).

3. The experiment, which is also a great example of how superposition works, is described like this: a cat, a flask of poison, and a radioactive source are placed in a sealed box. If an internal monitor detects radioactivity (i.e. a single atom decaying), the flask is shattered, releasing the poison that kills the cat. The Copenhagen interpretation of quantum mechanics implies that after a while, the cat is simultaneously alive and dead. Yet, when one looks in the box, one sees the cat either alive or dead, not both alive and dead.

4. The most commonly held interpretation of quantum mechanics is the Copenhagen interpretation. In the Copenhagen interpretation, a system stops being a superposition of states and becomes either one or the other when an observation takes place. This experiment makes apparent the fact that the nature of measurement, or observation, is not well-defined in this interpretation.

5. The Schrödinger experiment can be interpreted to mean that while the box is closed, the system simultaneously exists in a superposition of the states "decayed nucleus/dead cat" and "undecayed nucleus/living cat," and that only when the box is opened and an observation performed does the wave function collapse into one of the two states.

6. Quantum entanglement occurs when particles such as photons, electrons, molecules as large as buckyballs (https://en.wikipedia.org/wiki/Buckyballs), and even small diamonds interact physically and then become separated.

7.  The type of interaction is such that each resulting member of a pair is properly described by the same quantum mechanical description (state), which is indefinite in terms of important factors such as position, momentum, spin, polarization, etc.

8. Quantum entanglement is a form of quantum superposition. When a measurement is made and it causes one member of such a pair to take on a definite value (e.g., clockwise spin), the other member of this entangled pair will at any subsequent time be found to have taken the appropriately correlated value (e.g., counterclockwise spin). Thus, there is a correlation between the results of measurements performed on entangled pairs, and this correlation is observed even though the entangled pair may have been separated by arbitrarily large distances.

9.  In quantum entanglement, part of the transfer happens instantaneously. Repeated experiments have verified that this works even when the measurements are performed more quickly than light could travel between the sites of measurement: there is no slower-than-light influence that can pass between the entangled particles. Recent experiments have shown that this transfer occurs at least 10,000 times faster than the speed of light, which does not remove the possibility of it being an instantaneous phenomenon, but only sets a lower limit.

10. A quantum computer is a computation device that makes direct use of quantum mechanical phenomena, such as superposition and entanglement, to perform operations on data. Quantum computers are different from digital computers based on transistors. Whereas digital computers require data to be encoded into binary digits (bits), quantum computation uses quantum properties to represent data and perform operations on these data. (quantum computers will be the theme of the next fact list)

BONUS
11. How to Build Your Own Quantum Entanglement Experiment: http://blogs.scientificamerican.com/critical-opalescence/2013/02/08/how-to-build-your-own-quantum-entanglement-experiment-part-1-of-2/

DOUBLE-BONUS
12.
Quantum foam (also referred to as space time foam) is a concept in quantum mechanics devised by John Wheeler in 1955. The foam is supposed to be conceptualized as the foundation of the fabric of the universe. The idea comes from the attempts to merge relativistic gravity with quantum mechanics.
Gravity, Einstein proved, was a bending of the fabric of spacetime. It also behaves like a field. Place a point far away from the Earth, and it still will be part of the Earth’s gravitational field, but it will be out where the tug of gravity is weak. Place it close to the Earth, and the tug is stronger, and it will fall. Other planets warp spacetime and create their own gravitational tugs. So space isn't gravity-free, but a vast array of different gravitational tugs through which particles move. Pretty much everywhere that anything is placed, there is a gravitational field that it moves through.

Scientists have observed quantum tunneling. This happens when a particle goes through a barrier that it should not have the energy to penetrate. It would be something like slowly rolling a soccer ball at a thick wall and watching it suddenly pop out the other side. Particles that do it must be getting a vast quantity of energy from nowhere. Physicists believe that, over short period of time, particles can suddenly “borrow” energy and tunnel out. The shorter the period of time, the more energy they can borrow.

On a quantum scale, this isn’t so weird. Due to the Heisenberg Uncertainty Principle, the closer an object’s position is fixed, the more its momentum can fluctuate into unknown territory. If the particle’s position is definitely close to the wall, it might have the energy to tunnel through. And if the particle is going with a certain momentum, and you’re certain of that, its position might not be what you think.
We know that particles do make use of quantum tunneling, which means, from a conventional point of view, that over short periods of time they must “borrow” energy from the universe. And Einstein proved that energy and mass are equivalent. If the universe can borrow energy, why not mass?

Borrowing implies that the energy will be returned. The auditor of this particular debt is the law of conservation of energy. This is something that has also been observed. We don’t see energy popping up out of nowhere. We don’t see mass popping into existence. But then again, we’re not looking at small enough objects, or short enough time spans. If, when things get below a certain distance, energy can briefly pop into being, then so can particles. Those particles can have all different momenta, if they’re in existence briefly enough. As the spaces over which they appear get smaller and the time periods get shorter, the energy in the particles can get bigger and bigger.

Einstein showed that spacetime is a physical thing, and that it can get bent and stretched with mass and energy. These huge fluctuations in mass and energy over tiny, tiny distances have to churn it up. Over short enough distances in space, there would be tiny black holes and tiny planets, each stretching spacetime the same way that regular black holes and planets do. So as we zoomed in on spacetime, it wouldn’t be a smooth stretch of fabric deformed gently by large planets, it would be churned up, in constant motion, because of these tiny, but massive, fluctuations. Instead of fabric, we have foam.
 

[uNk]

Really enjoyed reading the black hole parts, thanks and keep this up!

[silenthunder]

I myself am really enjoying the quantum mechanics stuff, my friend and I always end up theorizing about quantum computers and such.

[Mordred]

Today's theme: Quantum Mechanics: #3 Quantum Computers

1. A quantum computer is a computation device that makes direct use of quantum mechanical phenomena, such as superposition and entanglement, to perform operations on data. Quantum computers are different from digital computers based on transistors. Whereas digital computers require data to be encoded into binary digits (bits), quantum computation uses quantum properties to represent data and perform operations on these data.

2. Although quantum computing is still in its infancy, experiments have been carried out in which quantum computational operations were executed on a very small number of qubits (quantum bits). Both practical and theoretical research continues, and many national government and military funding agencies support quantum computing research to develop quantum computers for both civilian and national security purposes, such as cryptanalysis.

3. Large-scale quantum computers will be able to solve certain problems much faster than any classical computer using the best currently known algorithms, like integer factorization using Shor's algorithm (https://en.wikipedia.org/wiki/Shor%27s_algorithm) or the simulation of quantum many-body systems. There exist quantum algorithms, such as Simon's algorithm (https://en.wikipedia.org/wiki/Simon%27s_algorithm), which run faster than any possible probabilistic classical algorithm. Given sufficient computational resources, a classical computer could be made to simulate any quantum algorithm; quantum computation does not violate the Church–Turing thesis.

4. A classical computer has a memory made up of bits, where each bit represents either a one or a zero. A quantum computer maintains a sequence of qubits. A single qubit can represent a one, a zero, or any quantum superposition of these two qubit states; moreover, a pair of qubits can be in any quantum superposition of 4 states, and three qubits in any superposition of 8.

5. In general, a quantum computer with n qubits can be in an arbitrary superposition of up to 2^n different states simultaneously (this compares to a normal computer that can only be in one of these 2^n states at any one time).

6. A quantum computer operates by setting the qubits in a controlled initial state that represents the problem at hand and by manipulating those qubits with a fixed sequence of quantum logic gates. The sequence of gates to be applied is called a quantum algorithm. The calculation ends with measurement of all the states, collapsing each qubit into one of the two pure states, so the outcome can be at most n classical bits of information. An example of an implementation of qubits for a quantum computer could start with the use of particles with two spin states: "down" and "up" to represent 0 and 1.

7. To better understand what collapsing the wave function would look like, imagine the following analogy: your qubits in a superposition are putty, your quantum algorithms are this. Collapsing the wave function is like pushing the putty through a shape. Initially it looks like a blob, but when you push it in, it will take the shape of the hole. If you take the same putty, make it a blob again, and push it through another hole, it will take that shape this time.  In a similar fashion the qubits take the "shape" of the solution of the problem, and the solution is defined by the quantum algorithm (a.k.a. the diagram of the logic gates).


If you've understood so far, you might be wondering: "well that's all fine and dandy, but what's the catch, why are the quantum computers supposed to be so much better?". Upcoming now:

8. Storage: One terabyte of information can store 2⁴³ discrete complex values before being full to 100% capacity. That means one trillion bits can store 2⁴³ values. By comparison, a mere 500 qubits can store 2⁵⁰⁰ values! Nielsen, Michael A. and Chuang, Isaac L. said in their book Quantum Computation and Quantum Information. p. 17. (31st Jan, 2011 | 10th edition) the following: "Trying to store all these complex numbers would not be possible on any conceivable classical computer." 

9. Data transfer: Quantum entanglement, as detailed yesterday, will be the basis of communications between two quantum computers. Just imagine transferring almost endless amounts of data with AT LEAST 10.000 times the speed of light between any two computers that were entangled previously. This is almost literal "instant communication".

10. And last, but not least, the most critical advantage of a quantum computer, power consumption. Due to the fact that a quantum computer does not need to store data in the same way as a normal computer, it is enough to give it power just so it can set the values of the qubits before pushing them inside the logic gate. Qubits are particles, not energy, which means after they travel through the algorithm, they come back to the start line and get reinitialized. In case you can't directly see it, this means that once you turn on a quantum computer, it will stay on by itself. It's of such a high efficiency, that scientists estimate a quantum computer will use the equivalent power of a normal computer (in chunks because it uses it just for resetting the qubits) but offer hundreds of thousands of times the performance!


As a side note, Monday I will be starting with M-theory and it's implications on our world. If you would like more information on quantum computers, or you would like to have more of an essay style paper for this topic, let me know and I will postpone Monday's theme and discuss that instead.
 

[lifecabal]

Okay, I am fucking interest in your Quantum computer, So more info would be more than welcome. A little off topic, did you know about A.I. stuff? How the brain think?

[Neea]

Truly fascinating, i finally managed to get the time to read all that
Your posts about quantum mechanics made me a bit sad that i didn't learn my physics all that great, but i managed to keep up with it at least. More info on it would be great

[Uriah]

Most interesting stuff ever....+ 1

[Mordred]

Been really busy these past few days with my Bachelor's thesis so I didn't have time to give you any more cool stuff here, but I did prepare some material.

Hopefully I have time today. If not, then tomorrow.

[Mordred]

Today's theme: String Theory

1. String theory is an active research framework in particle physics that attempts to reconcile quantum mechanics and general relativity. It is a contender for a theory of everything (TOE), a self-contained mathematical model that describes all fundamental forces and forms of matter.

2. String theory posits that the elementary particles (i.e., electrons and quarks) within an atom are not 0-dimensional objects, but rather 1-dimensional oscillating lines ("strings").

3. These strings can oscillate, giving the observed particles their flavor, charge, mass, and spin. Among the modes of oscillation of the string is a massless, spin-two state—a graviton.

4. The existence of this graviton state and the fact that the equations describing string theory include Einstein's equations for general relativity mean that string theory is a quantum theory of gravity. Since string theory is widely believed to be mathematically consistent, many hope that it fully describes our universe, making it a theory of everything.

5. String theory is known to contain configurations that describe all the observed fundamental forces and matter but with a zero cosmological constant and some new fields. Other configurations have different values of the cosmological constant, and are metastable but long-lived.

6. This leads many to believe that there is at least one metastable solution that is quantitatively identical with the standard model, with a small cosmological constant, containing dark matter and a plausible mechanism for cosmic inflation. It is not yet known whether string theory has such a solution, nor how much freedom the theory allows to choose the details.

7. An intriguing feature of string theory is that it predicts extra dimensions. In classical string theory the number of dimensions is not fixed by any consistency criterion. However, to make a consistent quantum theory, string theory is required to live in a spacetime of the so-called "critical dimension": we must have 26 spacetime dimensions for the bosonic string and 10 for the superstring.

8. The closest theory that managed to merge all the needed prerequisites is the 11-dimensional M-theory, which requires spacetime to have eleven dimensions (including time), as opposed to the usual three spatial dimensions and the fourth dimension of time. The original string theories from the 1980s describe special cases of M-theory where the eleventh dimension is a very small circle or a line, and if these formulations are considered as fundamental, then string theory requires ten dimensions.

9.  Nothing in Maxwell's theory of electromagnetism or Einstein's theory of relativity makes this kind of prediction; these theories require physicists to insert the number of dimensions manually and arbitrarily, and this number is fixed and independent of potential energy. String theory allows one to relate the number of dimensions to scalar potential energy.

10. Flat space string theories are 26-dimensional in the bosonic case, while superstring and M-theories turn out to involve 10 or 11 dimensions for flat solutions. In bosonic string theories, the 26 dimensions come from the Polyakov equation. Starting from any dimension greater than four, it is necessary to consider how these are reduced to four dimensional spacetime.

BONUS
11. In order for you guys to properly understand what you've just read, I offer you an old (2005) but still very very accurate explanation including visual helpers of String Theory and M-Theory. I will cover M-Theory in more detail to offer even more interesting information (discovered after the making of this video) and at the end, this post + video + next post should offer you a pretty decent image of the most basic, elementary, indivisible, simple explanation of what everything is made of: http://www.ted.com/talks/brian_greene_on_string_theory.html

[Uriah]

+1 for that, the video really explained string theory in a great way.

[Mordred]

Today's theme: M-Theory

1. In theoretical physics, M-theory is an extension of string theory in which 11 dimensions are identified. Proponents believe that the 11-dimensional theory unites all five 10 dimensional string theories and supersedes them.

2. Drawing on the work of a number of string theorists (including Ashoke Sen, Chris Hull, Paul Townsend, Michael Duff and John Schwarz), Edward Witten of the Institute for Advanced Study suggested its existence at a conference at USC in 1995, and used M-theory to explain a number of previously observed dualities, initiating a flurry of new research in string theory called the second superstring revolution.

3. In the early 1990s, it was shown that the various superstring theories were related by dualities which allow the description of an object in one super string theory to be related to the description of a different object in another super string theory. These relationships imply that each of the super string theories is a different aspect of a single underlying theory, proposed by Witten, and named "M-theory".

4. In the standard string theories, strings are assumed to be the single fundamental constituent of the universe. M-theory adds another fundamental constituent - membranes. Like the tenth spatial dimension, the approximate equations in the original five superstring models proved too weak to reveal membranes.

5. A membrane, or brane, is a multidimensional object, usually called a P-brane, with P referring to the number of dimensions in which it exists. The value of 'P' can range from zero to nine, thus giving branes dimensions from zero (0-brane ≡ point particle) to nine - five more than the world we are accustomed to inhabiting.

6. The inclusion of p-branes does not render previous work in string theory wrong on account of not taking note of these P-branes. P-branes are much more massive ("heavier") than strings, and when all higher-dimensional P-branes are much more massive than strings, they can be ignored, as researchers had done unknowingly in the 1970s.

7. One of the reasons M-theory is so difficult to formulate is that the numbers of different types of membranes in the various dimensions increases exponentially. For example once one gets to 3-dimensional surfaces, one has to deal with solid objects with knot-shaped holes, and then one needs the whole of knot theory just to classify them.

8. Shortly after Witten's breakthrough in 1995, Joseph Polchinski of the University of California, Santa Barbara discovered a fairly obscure feature of string theory. He found that in certain situations the endpoints of strings (strings with "loose ends") would not be able to move with complete freedom as they were attached, or stuck within certain regions of space. Polchinski then reasoned that if the endpoints of open strings are restricted to move within some p-dimensional region of space, then that region of space must be occupied by a p-brane. These type of "sticky" branes are called Dirichlet-P-branes, or D-P-branes.

9.  Not all strings are confined to p-branes. Strings with closed loops, like the graviton, are completely free to move from membrane to membrane. Of the four force carrier particles, the graviton is unique in this way.

10. Researchers speculate that this is the reason why investigation through the weak force, the strong force, and the electromagnetic force have not hinted at the possibility of extra dimensions. These force carrier particles are strings with endpoints that confine them to their p-branes. Further testing is needed in order to show that extra spatial dimensions indeed exist through experimentation with gravity.

BONUS
11. This is how the spatial dimensions would look like. So just like you know up-down, left-right, forward-back, each of the surfaces intertwining in the below picture represents A WHOLE SPATIAL DIMENSION. On each of these dimensions there is a vibrating string. As the dimensions move, the vibration of the string changes, and each unique pattern offers us an elementary particle. At the smallest of scales, this is (in theory) what absolutely EVERYTHING is made of, including empty space.

[WirelessDesert]

Nice, haven't read it all but still.
Also, how is school doing? Going well?

[Uriah]

Can you explain more about how strings produce elementary particles please? I understand what is going on, but if strings are always moving to form another particle, wouldn't matter/energy be constantly growing? Are there only certain rare situations when strings are "twanged" to create new particles?

[Mordred]

Can you explain more about how strings produce elementary particles please? I understand what is going on, but if strings are always moving to form another particle, wouldn't matter/energy be constantly growing? Are there only certain rare situations when strings are "twanged" to create new particles?

Sure Uriah. Just let me wrap up my thesis (happening this week) and I will get back to updating this thread more often and I'll also make a special on that.

For today though, boy do I have a treat for you guys:

Today's theme: SPECIAL - Do we actually live in something akin to the Matrix? (i.e. is our Universe a simulation?)





"
Dr. S. James Gates, Jr., a theoretical physicist, the John S. Toll Professor of Physics at the University of Maryland, and the Director of The Center for String & Particle Theory, is reporting that certain string theory, super-symmetrical  equations, which describe the fundamental nature of the Universe and reality, contain embedded computer codes.

These codes are digital data in the form of 1′s and 0′s. Not only that, these codes are the same as what make web browsers work and are error-correction codes! Gates says, “We have no idea what these ‘things’ are doing there”.

Gates discloses in the second video below, as an aside in a formal interview, that some of his research can be interpreted that we do live in a virtual reality. He describes this as “mind-blowing” and similar to the movie “The Matrix”! Further, he adds, that if someone suspected they did live in a virtual reality, then detecting computer codes would be a way to confirm. He concludes with finding these computer codes in equations that describe our world: “that’s what I just proposed!”.

What to make of this? There are two issues: 1) if String Theory will ultimately be a viable and therefore proven model of reality and 2) if so, whether embedded coding is in fact within the related verified equations. Michio Kaku has stated “String Theory Is the Only Game in Town” because it is the only testable theory available.
We have argued on this website that the Universe is a virtual reality. If true, then any theory of reality should eventually confirm this, if the theory has staying power and does not succumb to an early death. Accordingly, time is on the side of the simulation hypothesis to be verified first through theory and then via experiments in the long-run. Technology to provide the means to test that the Universe is a virtual reality is the next step.

“Doubly-even self-dual linear binary error-correcting block code,” first invented by Claude Shannon in the 1940′s, has been discovered embedded WITHIN the equations of superstring theory! Why does nature have this? What errors does it need to correct? What is an ‘error’ for nature? More importantly what is the explanation for this freakish discovery? Your guess is as good as mine."

Dr. S. James Gates video: http://www.youtube.com/watch?v=q1LCVknKUJ4&feature=player_embedded

[Uriah]

Excellent contribution! That was the most interesting I've ever seen lol. Just wondering why that video was 2012 and I hadn't heard of it yet. Glad to hear the voices of some of my favorite scientists as well.
+1.