Breaking the limits of classical physics

Jun 07, 2012
In the quantum optical laboratories at the Niels Bohr Institute, researchers have conducted experiments that show that light breaks with the classical physical principles. The studies show that light can have both an electrical and a magnetic field, but not at the same time. That is to say, light has quantum mechanical properties.

(Phys.org) -- With simple arguments, researchers show that nature is complicated. Researchers from the Niels Bohr Institute have made a simple experiment that demonstrates that nature violates common sense – the world is different than most people believe. The experiment illustrates that light does not behave according to the principles of classical physics, but that light has quantum mechanical properties. The new method could be used to study whether other systems behave quantum mechanically. The results have been published in the scientific journal, Physical Review Letters.

In physics there are two categories: and quantum physics. In classical physics, objects, e.g. a car or a ball, have a position and a velocity. This is how we classically look at our everyday world. In the quantum world objects can also have a position and a velocity, but not at the same time. At the atomic level, quantum mechanics says that nature behaves quite differently than you might think. It is not just that we do not know the position and the velocity, rather, these two things simply do not exist simultaneously. But how do we know that they do not exist simultaneously? And where is the border of these two worlds? Researchers have found a new way to answer these questions.

Light on quantum mechanics

“Our goal is to use quantum mechanics in a new way. It is therefore important for us to know that a ‘system’ really behaves in a way that has no classical explanation. To this end, we first examined light,” explains Eran Kot, PhD-student in the research group, Quantum Optics at the Niels Bohr Institute at the University of Copenhagen. 

Based on a series of experiments in the quantum optics laboratories, they examined the state of light. In classical physics, light possesses both an electric and a magnetic field.

“What our study demonstrated was that light can have both an electric and a magnetic field, but not at the same time. We thus provide a simple proof that an experiment breaks the classical principles. That is to say, we showed light possesses quantum properties, and we can expand this to other systems as well” says Eran Kot.

Classical and non-classical mechanics

The aim of the research is both to fundamentally understand the world, but there is also a practical challenge in being able to exploit in larger contexts. For it is no great surprise that it behaves quantum mechanically, but the methods that have been developed can also be used to study other systems.

“We are endeavouring to develop future quantum computers and we therefore need to understand the borders for when something behaves quantum mechanically and when it is classical mechanics,” says professor of quantum physics Anders S. Sørensen, explaining that quantum computing must necessarily be comprised of systems with non-classical properties.

Explore further: Quantum holograms as atomic scale memory keepsake

More information: prl.aps.org/abstract/PRL/v108/i23/e233601

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User comments : 32

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CWonPhysOrg
4.8 / 5 (23) Jun 07, 2012
Am I the only one that thinks this article has quantum characteristics? That is, no content, no description of the subject, has spin, no charge, and no direction.
Origin
1 / 5 (10) Jun 07, 2012
I don't think, the quantum mechanics is non-classical. We know about many classical analogies of quantum phenomena - so it's not possible to claim, quantum mechanics cannot be explained classically, if it can be modelled so experimentally.
JES
5 / 5 (20) Jun 07, 2012
It cannot be an article and carry content at the same time..obviously!
Origin
1.2 / 5 (18) Jun 07, 2012
A recent study, which provides classical (statistical) interpretation of quantum mechanics too. Dense aether model provides many mechanical analogies of QM phenomena. It's just the matter of scope, whether emergent phenomena will behave classically of quantum mechanically. For example, huge rogue waves at the ocean surface are modelled with Schrödinger equation routinely.
ryggesogn2
1.4 / 5 (9) Jun 07, 2012
"All models are wrong. Some are just more useful." G.E.P. Box.
antialias_physorg
3.8 / 5 (10) Jun 07, 2012
You cannot explain quantized behavior (single detector events) and interference patterns observed in single electron/photon double-slit experiments. You just have to let go of the naive, everyday analogies - no matter how 'unsatisfying' may be to the ego.

Mesurement and reality trumps the human need for stuff to fit to analogies every time.
Moebius
2.9 / 5 (14) Jun 07, 2012
Position and velocity don't exist simultaneously? Why, because we don't have a non-interfering method of measuring those things? Our ability to find an explanation for anything we don't understand fully, no matter how non-sensical, is amazing. What we don't know is probably still at least half-vast.
antialias_physorg
3.8 / 5 (11) Jun 07, 2012
Why, because we don't have a non-interfering method of measuring those things?

The mode of measurement is irrelevant for this (the pgysics behind the Uncertainty Principle is independent of measurement apparatus types)

It's due to the two variables (e.g. impuslse and loaction) being conjugate variables (you have to take do a fourier transfrom to get from one to another). A localized entity in one space is completely delocalized in its fourier transformed space.

What you are thinking of is the 'observer effect' (i.e. that some interaction must take place between the measured entity and the observer to convey the information from the former to the latter). The Uncertainty Principle, however, does not depend on the observer effect.
andrew_hughmann
5 / 5 (1) Jun 07, 2012
I hate to over simplify...but light not having a mixed reaction at the same time seems reasonable...all or nothing, like or not, good or bad...throwing lightning bolts or attraction principles.
antialias_physorg
3.7 / 5 (3) Jun 07, 2012


There are a number of such conjugate variables we know of. Speed(impulse) and location, action and angular momentum, energy and time...
geokstr
3.4 / 5 (15) Jun 07, 2012
What we don't know is probably still at least half-vast.


And what we don't even know we don't know no doubt dwarfs what we simply don't know.
Terriva
1 / 5 (10) Jun 07, 2012
You cannot explain quantized behavior .. and interference patterns observed in single electron/photon double-slit experiments
The very same interference patterns are formed during classical analogy of double slit experiment. If you can explain this macroscopic analogy, then you can explain even this microscopic one. It's really as simple, as it is. Quantized behavior can be explained with water surface analogy too.

The only reason, why proponents of mainstream physics pretend, these simple analogies cannot be used for explanation of quantum mechanics is, they point clearly to the aether model, which was misinterpreted with mainstream physics before years and now the physicists are trying not to lost their face (and social credit) before layman publics. It's really as simple, as it is.
Terriva
1.4 / 5 (10) Jun 07, 2012
Position and velocity don't exist simultaneously? Why, because we don't have a non-interfering method of measuring those things?
If you would live like the waterstrider at the water surface and the surface ripples would be the only subject and object of your observations, you would have to balance the wavelength for observation of objects all the time. Too long wavelength ripples would give you only rough information about size and location of another tiny objects, whereas the shortwavelength waves are too energetic and they would shake tiny objects too much, thus making the observation of their speed difficult. It's just the matter of distance scale, what makes this water surface analogy relevant for quantum mechanics.
Lurker2358
1.4 / 5 (10) Jun 07, 2012
Velocity is defined as the rate of change in position, so how could you know the velocity in an experiment, and NOT know the position?

In fact, when you detect the kinetic energy of a cosmic ray particle striking a detector, it is only logical that you MUST know both the position and the kinetic energy.

If you know the kinetic energy, you know the velocity, based on parameters of identifying the particle type that struck the detector you can find the particle's rest mass, and therefore calculate it's velocity backwards using kinetic energy formula.

So I continue to disagree with this claim in QM.

The position is absolutely forced, because it's at a precise location on the detector, and the velocity is recoverable by taking kinetic energy of impact, and with a few subsequent measurements you can identify what type of particle it was, gives rest mass.

Ek = (1/2) mv^2
julianpenrod
1 / 5 (4) Jun 07, 2012
The article is actually very suspicious, overall.
For those who understand what's around them, the claim of not being able to monitor the electric field andthe magentic fields of a photon simultaneously is questionable in the extreme. The description of a light wave, actually, is a pair of coordinated oscillating electric and magnetic fields. The oscillating electric field gives rise to the magnetic field. But, at the same time, the oscillating magentic field gives rise to the oscillating electric field! In other words, the electric field creates the magnetic field that creates the electric field which vcreates the magentic field! Because they are not separate values in Heisenberg's uncertainty inequality, it's questionable if you could view one but not be able to view the other.
vacuum-mechanics
1 / 5 (3) Jun 07, 2012
... The description of a light wave, actually, is a pair of coordinated oscillating electric and magnetic fields. The oscillating electric field gives rise to the magnetic field. But, at the same time, the oscillating magentic field gives rise to the oscillating electric field! In other words, the electric field creates the magnetic field that creates the electric field which vcreates the magentic field!


This is the familiar conventional way explanation for propagation of light wave. But it seems impossible, the reason because both electric and magnetic field were created at the same time, and this will contradict to the principle of causality! May be this unconventional view could give some hint.

http://www.vacuum...id=21=en
julianpenrod
1 / 5 (3) Jun 07, 2012
It is not absolutely impossible that the electric and magnetic field are created simulatenously simply on the basis of causality. It is just as possible that causality is deeply flawed. It should be mentioned that it is by assuming a mutually generating combination of fields and applying Maxwell's equations to them that the value of the speed of light was derived exactly as the inverse of the square root of the product of the permittivity of free space and the permeability of space. At least to the extent that that is accepted, the model is legitimate.
antialias_physorg
5 / 5 (7) Jun 08, 2012
Velocity is defined as the rate of change in position, so how could you know the velocity in an experiment, and NOT know the position?

Because what you're measuring when you measure rate of change is two positions and two times (initial position/time and final püosition/time) from which you compute velocity.
For microscopic entities that doesn't work because your initial measurement interacts with the particle and changes its velocity/direction/position/whatever...so that your final measurement will be off.

So what you do instead is you measure the impulse (which is velocity times mass) when the entity strikes a detector. Knowing the mass you can calculate the velocity (without knowing the position exactly). Conversely you can make measurements of the position (using 'which way' detectors) without knowing the speed.
Lurker2358
1.8 / 5 (5) Jun 08, 2012

So what you do instead is you measure the impulse (which is velocity times mass) when the entity strikes a detector. Knowing the mass you can calculate the velocity (without knowing the position exactly). Conversely you can make measurements of the position (using 'which way' detectors) without knowing the speed.

But that's what I said in the second half of the post.

If you know "where" the particle struck on the detector, and you also know it's kinetic energy, then you in fact do know both it's position and velocity at the same time.

The claim is BS...
Lurker2358
1.8 / 5 (5) Jun 08, 2012
It is not absolutely impossible that the electric and magnetic field are created simulatenously simply on the basis of causality. It is just as possible that causality is deeply flawed.


Causality need not be flawed at all.

Many oscillating systems exist in nature. Creating an oscillating system from scratch does not in any way violate causality.

to illustrate, research the little 2-d game "Life," and consider the "kite" configuration. You can create any "Kite" configuration from scratch, and then if you follow the rules and run the game forward a few rounds, then it will oscillate, changing it's orientation, but always existing.

Perfect example of two or more states oscillating between one another, or being co-dependent on one another, and yet in no way violating causality.

Try it.

"There's no practical us for Radio." - Lord Kelvin.

Just remember that. Even brilliant people make absurd mistakes. one day so much we think we know will be vain.
Smashin_Z_1885
2 / 5 (4) Jun 09, 2012
Causality is not flawed, in fact, nothing is flawed in and of itself, or it's existence or non-existence, in any way whatsoever. What is flawed, however, is the current understanding of things. I have been saying this for years, and years and years and years already; that, the entire thing, all of it, is based on assumptions that are 'assumed' to be true, but which are in fact NOT TRUE! This is the basis for this idiotic and imagined conflict between the behaviour of items within the 'quantum' world, and the 'classical' world. And the even worse question: "Where is the boundary between the two?" There is NO boundary!!! I will not give you the answers. However, I am at liberty to say that you'll eventually figure it out. I know, otherwise I could not be here expressing such. 1. A vague hint: Observation is key, or, as one put it: this is the cause for information flowage (and conscious analysis)
S.Z. 5 14' -1908
1885
1840 Aug. 22
Smashin_Z_1885
2 / 5 (4) Jun 09, 2012
Let us assume the following: 1. A sheet music script written by Mozart is discovered by a scientist. Himself and likeminded men study it intensely, and discover some 'false truths; such as: a) There are distinct patterns of ink here, imbedded on a fibrous substance. b) Later study PROVES that these ink patterns are predictable, and therefore equations may be written to theorize about what they mean. c) Later, experiments "prove" these patterns can be re-produced in the laboratory, over and over again. d) a new 'law' is instituted, that; ink patterns on fibrous material always behave a certain way, and that the ink produces contrasting light signals on the white paper, various shapes exist and can be easily manipulated in the lab, and, new colors of ink can be produced, and many types of fibrous materials can be produced, and equations written to predict how the ink and paper will react to each other in various experimental situations.
The music; however, is never discovered.
S.Z.
antialias_physorg
not rated yet Jun 09, 2012
With single photon emissions/detections you get shot noise
en.wikipedia.org/wiki/Shot_noise

Note that shot noise is not a factor of how good your detector is (i.e. you can't reduce it, no matter what technica tricks you apply*) but is a fundamental distribution due to the uncertainty principle.

* you can go as low as the uncertainty limit, however, in 'squeezed' states.
http://en.wikiped...nt_state
Sonhouse
1 / 5 (1) Jun 09, 2012
It's amazing to me all you twitter scientists can do so much with so little.
Anda
3 / 5 (2) Jun 10, 2012
Hey "water ripples" aka terriva aka origin aka... Please, enlight us with the analogy between quantum behaviour and water waves :)
U are the only one in the world that understand quantum behaviour (it's so simple to u).
Why these morons haven't give u yet the Nobel prize you deserve... It's a global conspiration!
Terriva
1 / 5 (4) Jun 10, 2012
analogy between quantum behaviour and water waves
Analogy 1 (quantum orbitals), 2 (quantum tunelling), 3 (double slit experiment), 4 (Hawking radiation), some older review. The water surface is behaving like the quantum wave in certain extent, because it's surface are increases with level of its deforms and undulation, so it behaves like more dense environment for another waves. The Schrodinger equation describes the vibrations of string, the mass density of which is proportional the (both kinetic both potential) energy density in each time and space interval.
Terriva
1 / 5 (4) Jun 10, 2012
BTW The rogue waves are routinely modeled with Schrodinger equation (1, 2) and no one is surprised with it. The quantum effects are both microscopic both macroscopic in dense aether model, so they're the more apparent, the larger their scope is.
Deesky
5 / 5 (3) Jun 10, 2012
The quantum effects are both microscopic both macroscopic in dense aether model

You must be operating under the Dense Brain Model (DBM), which exhibits both microscopic intelligence and macroscopic stupidity.
Noumenon
1 / 5 (4) Jun 10, 2012

So what you do instead is you measure the impulse (which is velocity times mass) when the entity strikes a detector. Knowing the mass you can calculate the velocity (without knowing the position exactly). Conversely you can make measurements of the position (using 'which way' detectors) without knowing the speed.


If you know "where" the particle struck on the detector, and you also know it's kinetic energy, then you in fact do know both it's position and velocity at the same time.

The claim is BS...


You have to be careful to define the detector you're speaking of precisely. For example, in bubble chambers, entire paths of subatomic particles can be obervered and their momentum can be determined given their curvature in a magnetic field. This does not violate the uncertainty principal.

These bubbles are in the macroscopic scale, far larger than the product of uncertainty in position and momentum for a specific point.
Noumenon
1 / 5 (4) Jun 10, 2012
dp
Origin
1 / 5 (4) Jun 11, 2012
Recently the discussions, whether the quantum wave function is a real physical object emerged in connection to successful measurements of this wave function in chain of consecutive observations (stroboscopically, tomographically, weak measurements). IMO if we can measure something, than it exists physically, especially when we have a robust verified physical theory for it. But the physical existence of quantum wave function is closely connected with physical existence of superluminal motion, which this function describes. Therefore, if the quantum wave is real, then this superluminal motion is real as well and we can consider it in another explanation. In dense aether model the quantum wave function describes the superluminal pressure waves (gravitational waves), which do control the evolution of observable objects at the space-time.
Origin
1 / 5 (4) Jun 11, 2012
The problem is similar to the observation of underwater sound waves with surface ripples and objects which are formed with it at the water surface. We cannot observe these underwater phenomena with surface waves, because they're spreading a way faster, than the surface ripples. But can we therefore say, these underwater waves don't exist? If we would observe the water surface with faster waves (like the sound or even light waves), then we would see, that these underwater phenomena are indeed real. The mainstream physics is therefore in schizophrenic situation by now: in context of quantum mechanics it developed concepts, which do apparently violate the special relativity. Not only about it: these concepts aren't solely abstract, but they do appear observable in certain extent.