The First Ever Photograph of Light as both a Particle and Wave

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The First Ever Photograph of Light as both a Particle and Wave

Post by LongtimeAirman on Thu Mar 05, 2015 10:13 pm

I hope you find this interesting,

The first ever photograph of light as both a particle and wave

http://actu.epfl.ch/news/the-first-ever-photograph-of-light-as-both-a-parti/



02.03.15 - Light behaves both as a particle and as a wave. Since the days of Einstein, scientists have been trying to directly observe both of these aspects of light at the same time. Now, scientists at EPFL have succeeded in capturing the first-ever snapshot of this dual behavior.
Quantum mechanics tells us that light can behave simultaneously as a particle or a wave. However, there has never been an experiment able to capture both natures of light at the same time; the closest we have come is seeing either wave or particle, but always at different times. Taking a radically different experimental approach, EPFL scientists have now been able to take the first ever snapshot of light behaving both as a wave and as a particle. The breakthrough work is published in Nature Communications.
When UV light hits a metal surface, it causes an emission of electrons. Albert Einstein explained this “photoelectric” effect by proposing that light – thought to only be a wave – is also a stream of particles. Even though a variety of experiments have successfully observed both the particle- and wave-like behaviors of light, they have never been able to observe both at the same time.
A research team led by Fabrizio Carbone at EPFL has now carried out an experiment with a clever twist: using electrons to image light. The researchers have captured, for the first time ever, a single snapshot of light behaving simultaneously as both a wave and a stream of particles particle.
The experiment is set up like this: A pulse of laser light is fired at a tiny metallic nanowire. The laser adds energy to the charged particles in the nanowire, causing them to vibrate. Light travels along this tiny wire in two possible directions, like cars on a highway. When waves traveling in opposite directions meet each other they form a new wave that looks like it is standing in place. Here, this standing wave becomes the source of light for the experiment, radiating around the nanowire.
This is where the experiment’s trick comes in: The scientists shot a stream of electrons close to the nanowire, using them to image the standing wave of light. As the electrons interacted with the confined light on the nanowire, they either sped up or slowed down. Using the ultrafast microscope to image the position where this change in speed occurred, Carbone’s team could now visualize the standing wave, which acts as a fingerprint of the wave-nature of light.
While this phenomenon shows the wave-like nature of light, it simultaneously demonstrates its particle aspect as well. As the electrons pass close to the standing wave of light, they “hit” the light’s particles, the photons. As mentioned above, this affects their speed, making them move faster or slower. This change in speed appears as an exchange of energy “packets” (quanta) between electrons and photons. The very occurrence of these energy packets shows that the light on the nanowire behaves as a particle.
“This experiment demonstrates that, for the first time ever, we can film quantum mechanics – and its paradoxical nature – directly,” says Fabrizio Carbone. In addition, the importance of this pioneering work can extend beyond fundamental science and to future technologies. As Carbone explains: “Being able to image and control quantum phenomena at the nanometer scale like this opens up a new route towards quantum computing.”
This work represents a collaboration between the Laboratory for Ultrafast Microscopy and Electron Scattering of EPFL, the Department of Physics of Trinity College (US) and the Physical and Life Sciences Directorate of the Lawrence Livermore National Laboratory. The imaging was carried out EPFL’s ultrafast energy-filtered transmission electron microscope – one of the two in the world.

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Re: The First Ever Photograph of Light as both a Particle and Wave

Post by Cr6 on Fri Mar 06, 2015 2:30 am

That's an interesting experiment.   Found this paper from Mathis that might give more clarity around their recent findings and pictures.

This is the classical explanation:

http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/photel.html


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The COMPTON EFFECT, DUALITY
and the Klein-Nishina Formula

by Miles Mathis 

http://milesmathis.com/comp.html

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Abstract: I will show that the Compton effect has been incompletely explained due simply to the Copenhagen interpretation, and the failure to explain duality. I will complete the mechanical explanation and show the genesis of the field and the wave. I will then correct the Klein-Nishina formula by importing my new value for the electron radius. This will give us the same result as before, but with a vastly improved and more transparent derivation.


The Compton Effect is an inelastic scattering of high-energy photons by electrons. It was observed by Arthur Compton in 1923, in an experiment with X-rays. Like the photo-electric effect, it has correctly been interpreted as proof of the photon theory of light. That is, it is proof of the “particle” half of duality, and of Newton's corpuscular theory. This effect led directly to the Copenhagen interpretation of light, where Bohr insisted that light was both particle and wave, but also insisted this duality could not be understood mechanically or logically.

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Although current theory on Compton scattering and Thomson scattering is much more filled out than current theory on Rayleigh scattering, it is still very incomplete. It is incomplete because no one has been able to say how the duality expresses itself. It is well understood that Slater's field doesn't work, since the data can't be fit to photons carried that way by field oscillations. Slater was trying to explain interference and polarization and so on with the field, and the Compton effect with the photon, but when it came to explaining how the particle interacted with the field, he was at a loss. Particle physics is still at a loss, which is why they stick with the math and dodge all mechanics.
 
But I can explain the mechanics. The problem is that everyone from Newton and Huygens to Maxwell and Slater and Einstein has tried to express the wave as a field wave. But the wave of light is not a field wave. The wave belongs to each photon itself, and this is what solves the problem (as I have shown in several papers1). All these theorists could not get out of the rut of thinking of light as an analogy to sound or other field waves. Because all the waves they had been taught in school had been field waves, they naturally thought light must be a field wave, too. So when it was proved by Einstein that light was not traveling via an ether, they were stumped. If there was no field, how could there be a wave? No one has gotten past that apparent dilemma.

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This mechanism of spin also explains inverse Compton scattering, since we only have to turn our photons upside down to explain it. Spins are reversed just by a pole reversal. Photons can be spinning CW or CCW relative to electrons, and in one case the angular momenta will add in collision and in the other it will subtract. A subtraction will increase the wavelength of the photon, and an addition will decrease the wavelength.

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Re: The First Ever Photograph of Light as both a Particle and Wave

Post by LongtimeAirman on Sat Mar 07, 2015 10:22 pm

Thank You Sir, A fine repast.

I thought I was doin’ great, “Photons can be spinning CW or CCW relative to electrons, and in one case the angular momenta will add in collision and in the other it will subtract. A subtraction will increase the wavelength of the photon, and an addition will decrease the wavelength.”

Wham, the wavelength results threw me into a spin. I stood there for several confused moments as the statement sank into my skull. So between yesterday and today, in bits and pieces, I re-read Compton and more Compton. And then some more.

I can now say, “why, but of course!”

Sidenote, I couldn’t find  The Compton Wavelength as evidence for the Photon Wavefunction http://milesmathis.com/comp3.pdf, on Miles’ Index page list http://milesmathis.com/index.html . comp3 can be found on the Updates page http://milesmathis.com/updates.html. Please mention it to Miles, I’m too shy.

The surface spin levels in our laser targeted nano-wire above, flip between high energy photons and electrons. I guess we are seeing a coherent interference pattern. Unfortunately, it also seems to bolster the incorrect “wave theory” portion of the particle, wave duality. What appears to be a standing wave of high energy photons (or electrons dropping their energy and turning into photons?). I see I'm going to have to continue reading.

Thanks too for the http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/photel.html Hyperlink. They have really improved their site since I saw it last.

“All’s well”

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Re: The First Ever Photograph of Light as both a Particle and Wave

Post by Cr6 on Sun Mar 08, 2015 1:16 am

Good to hear "Alls Well" LTAM.  That's really good news.

You know I forgot about that Comp3.pdf.  That really details it in terms of photon over electron. 

This whole piece gets one thinking of a "photon" computer instead of a "quantum" computer. I suspect it would be easier to program with the right arrangement of Charge Flows(?).  Maybe we should patent it (of course with MM on it as well) Cool ? The Comp3.pdf gives a few hints on how to build one. If much of "quantum" computing can be reinterpreted in terms of the charge field, like why not try it? In the everyday world of "quantum" physics, it appears quantum computing is the only practicle application. Miles might allow a short-cut to what actually works.
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https://en.wikipedia.org/wiki/Single-electron_transistor



The Kane quantum computer is a proposal for a scalable quantum computer proposed by Bruce Kane in 1998,[1] who was then at the University of New South Wales. Often thought of as a hybrid between quantum dot and NMR quantum computers, the Kane computer is based on an array of individual phosphorus donor atoms embedded in a pure silicon lattice. Both the nuclear [url=javascript(0)]spins[/url] of the donors and the spins of the donor electrons participate in the computation.


Nuclear spins alone will not interact significantly with other nuclear spins 20 nm away. Nuclear spin is useful to perform single-qubit operations, but to make a quantum computer, two-qubit operations are also required. This is the role of electron spin in this design. Under A-gate control, the spin is transferred from the nucleus to the donor electron. Then, a potential is applied to the J gate, drawing adjacent donor electrons into a common region, greatly enhancing the interaction between the neighbouring spins. By controlling the J gate voltage, two-qubit operations are possible.
Kane's proposal for readout was to apply an electric field to encourage spin-dependent tunneling of an electron to transform two neutral donors to a D+–D state, that is, one where two electrons orbit the same donor. The charge excess is then detected using a single-electron transistor. This method has two major difficulties. Firstly, the D state has strong coupling with the environment and hence a short decoherence time. Secondly and perhaps more importantly, it's not clear that the D state has a sufficiently long lifetime to allow for readout—the electron tunnels into the conduction band.

Unlike many quantum computation schemes, the Kane quantum computer is in principle scalable to an arbitrary number of qubits. This is possible because qubits may be individually addressed by electrical means.
Since Kane's proposal, under the guidance of Robert Clark and now Michelle Simmons, pursuing realisation of the Kane quantum computer has become the primary quantum computing effort in Australia.[2] Theorists have put forward a number of proposals for improved readout. Experimentally, atomic-precision deposition of phosphorus atoms has been demonstrated, using an STM technique. Detection of the movement of single electrons between small, dense clusters of phosphorus donors has also been achieved. The group remains optimistic that a practical large-scale quantum computer can be built. Other groups believe that the idea needs to be modified

https://en.wikipedia.org/wiki/Kane_quantum_computer

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One step closer to a quantum computer
Date:
April 30, 2013
Source:
Linköping Universitet
Summary:
Scientists have succeeded in both initializing and reading nuclear spins, relevant to qubits for quantum computers, at room temperature.
Professor Weimin Chen and his colleagues at Linköping University, in cooperation with German and American researchers, have succeeded in both initializing and reading nuclear spins, relevant to qubits for quantum computers, at room temperature.

The results have just been published in the journal Nature Communications.
A quantum computer is controlled by the laws of quantum physics; it promises to perform complicated calculations, or search large amounts of data, at a speed that exceeds by far those that today's fastest supercomputers are capable of.

"You could say that a quantum computer can think several thoughts simultaneously, while a traditional computer thinks one thought at a time," says Weimin Chen, professor in the Division of Functional Electronic Materials at the Department of Physics, Chemistry and Biology at LiU, and one of the main authors of the article in Nature Communications.
A traditional computer stores, processes and sends all information in the form of bits, which can have a value of 1 or 0. But in the world of quantum physics, at the nano- and atomic level, other rules prevail and a bit in a quantum computer -- a qubit -- can have any value between 1 and 0. A spin-based qubit makes use of the fact that electrons and atomic nuclei rotate around their own axes -- they have a spin. They can rotate both clockwise and counterclockwise (equivalent to 1 and 0), and in both directions simultaneously (a mix of 1 and 0) -- something that is completely unthinkable in the traditional, "classical" world.
An atomic nucleus consists of both protons and neutrons, and the advantage of using the nuclear spin as a qubit is that the nucleus is well protected, and nearly impervious to unwanted electromagnetic disturbance, which is a condition for keeping the sensitive information in the qubit intact.

The first step in building a quantum computer is to assign each qubit a well-defined value, either 1 or 0. Starting, or initiating, the spin-based qubits then requires all the atomic nuclei to spin in the same direction, either 'up' or 'down' (clockwise or counterclockwise). The most common method for polarising nuclear spin is called dynamic nuclear polarisation; this means that the electrons' spin simply influences the nucleus to spin in the same direction. The method requires strongly spin polarised electrons and functions superbly at lower temperatures. Dynamic nuclear polarisation via conduction electrons has, however, not yet been demonstrated at room temperature -- which is crucial for the method to be useful in practice for the development of quantum computers. The main problem is that the spin orientation in the electrons can easily be lost at room temperature, since it is sensitive to disruptions from its surroundings.

http://www.sciencedaily.com/releases/2013/04/130430092420.htm

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Proposed Quantum Computer Consists of Billions of Electron Spins
Sep 09, 2009 By Lisa Zyga



Enlarge
The physical setup of the quantum computer consists of a superconducting transmission line cavity coupled to an ensemble of electron spins and a transmon Cooper pair box. The cavity dimensions allow 100 billion electron spins to be coupled to the cavity mode, which could be used to make hundreds of physical qubits. Image copyright: J.H. Wesenberg, et al.  
(PhysOrg.com) -- While researchers have already demonstrated the building blocks for few-bit quantum computers, scaling these systems up to large quantum computers remains a challenge. One of the biggest problems is developing physical systems that can reliably store thousands of qubits, and enabling bits and pairs to be addressed individually for gate operations.

With this issue in mind, scientists have recently proposed a quantum computing scheme that uses an ensemble of about 100 billion electron spins. They show that hundreds of physical qubits can be made from these collective electron spin excitations. The researchers, Janus Wesenberg from the University of Oxford, and coauthors from Oxford, Yale University and the University of Aarhus in Denmark, have published the proposed system in a recent issue of Physical Review Letters.

The system can also perform qubit encoding and provide one- and two-bit gates for quantum computing. In the setup, the electron spins are coupled to a superconducting transmission line cavity. In turn, this cavity is coupled to a transmon Cooper pair box that carries out the gate operations.
“A single electron spin only interacts very weakly with its environment: this makes it a good quantum memory, except that it is very hard to initialize or read out,” Wesenberg explained to PhysOrg.com. “In the ensemble register we make use of the fact that the collective interaction between an ensemble of billions of spins and a microwave cavity is greatly enhanced by the so-called superradiant effect. This makes it possible to transfer a microwave photon (carrying a qubit), from the cavity to the spin ensemble in a few tens of nanoseconds compared to a significant fraction of a second for a single spin. Once the photon has been transferred to the ensemble, it lives as an delocalized excitation.

http://phys.org/news171705608.html

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