Laser Make 3-D Holograms....Giant Atoms Interact with 1000's In a BEC....Graphene Shows Record Breaking Super Conductive Properties....Google's Attempt at Quantum Supremacy.

Image Credit:- wikimedia

Introduction

Today I will present to you 4 advancements in science that have been made pretty recently. You'll find out about true 3-D holograms, personally I'd love to see this type of technology advance, maybe one day we could have holographic cinema. The hologram manifestation differs to the usual flat holograms you see, they use lasers instead to control particles. Giant quasi-atoms have been produced in a Bose-Einstein Condensates, they have quantum energy levels that extends it's size to micrometers, much much larger than the size of atoms. Pure-Carbon Graphene has been successfully manipulated to produce super conductivity take the record for highest density of charge carrier; allowing it to transmit a lot of electric. Google recently announced it's new addition to the world of quantum computing, the Bristlecone Quantum Processor could achieve "quantum supremacy".

I hope in this article you can learn about some of our latest achievements in the world of science and technology. There is a hidden connection, see if you can spot it, I'll tell you at the end, but don't cheat :D

3-D Holograms

Image Credit:- wikimedia

Two photographs of a single 2-D hologram taken from different viewpoints.

You should be familiar with a hologram, you'll have them on your banks cards, on bank notes, and sometimes on clothes like the baseball caps. You'll notice it is different to a photograph, which is produced by when light hits a photographic film. Holograms are a different, instead of recording the photons of light on a film, they are a recording of the light field of the object. Holograms look 3D when observed due to the interpretation and reconstruction of the light field of the object, like the mouse above.

The holographic image is an encoding of the light field as an interference pattern; how the light waves interfere. The interference pattern is created with different surface profiles, density, and opacity of the graphic material. When the material is illuminated the 3-D image is produced as a result of the diffraction (re-direction) of light from the interference pattern. As you move the image around, and change how it's observed you will notice depth and perspective of the image.

Image Credit:- wikimedia

I want to help you visualise what is going on here. In the picture below you see an interference pattern in the center, it's caused by multiple light waves interacting with each other. The holographic film has a complex surface that causes light to reflect off the surface in such a way that it interferes and forms the image. The interference pattern allows you to move the hologram around to see it's depth, you are observing a continuous complex interference pattern that varies as you move it around, but it will repeat the pattern when moved too far.

Image Credit:-wikimedia

Two light waves travel left to right, as they cross the wave like behaviour interferes and producing and interference pattern.

If you have a bank note with the hologram, take a look and you'll see this effect first hand.

What we have talked about so far is still kind of 2-D, in the sense that it exists on a "flat" surface. Scientists have found a way to project true 3-D images, a physicist called Daniel Smalley and his team use lasers to make 3-D moving images. The technique is called volumetric display, and it's name refers to the image having a volume, you can walk around the hologram and see it 360 degrees.

It's acts like a "high speed Etch sketch", using one set of lasers to move a small number of trapped particles around, then another set of lasers to give the particles colour, this combination generates the image. The controlling lasers take advantage of something called a the dipole force, it allows light to trap and control small particles, "optical tweezers" are used in many areas that uses this same principle.

The laser's move the particles around in the shape of the image with a certain frequency, this causes limitations. The human eye can can not see more than about 25 frames per second, so the laser must be able to move the particles around the full image faster than 25 Hertz. This forces the limitation of producing more complex images with this technique.

At the moment the technique and implementation is in it's early stages, only simple line images that are millimetres in size are been produced due to the limitation discussed. This technique is not the same as flat holograms discussed earlier, they use interference of light waves, these move particles fast and illuminate them with lasers.

Giant Atoms

Image Credit:-tuwien.ac.at

A few weeks back I came across a new study that involves the study of Bose-Einstein-Condensates (you can read some articles on my blog), it involves a kind of "giant atom". The mathematical description of this "particle" called the wave function predicts that it's radius is micro meters, which is huge compared to normal atoms.

As I mentioned it's discovery comes from studying Bose-Einstein Condensates (BEC), which is a collection of the same atoms that are in the exact same quantum state at very low temperatures. I suggest readers to take a look at this article if you are not familiar with this, or are curious.

Image Credit:- wikimedia

Electron orbital of a Rydberg atom with n=12. Colors show the quantum phase of the highly excited electron.

The scientist studies the interaction of a single localised electron the a BEC, the interaction would excite something called phonons (quantized vibrational modes), which resulted in large scale oscillations of the condensate. The electron was "trapped" by a charged (ionic) core which formed a Rydberg state. A Rydberg atom is an atom with one or more of it's electrons in a highly excited state with a large quantum number n that describes it's energy level. This Rydberg state produced by the coupling had a wave function that extended up to millimetres which is the same size scale of the condensate it excited. The quantum number/energy level of the state was n=202, at this energy level it was interacting with thousands of atoms in the condensate, causing phonon excitation (vibrations).

So to sum it up, an electron in a very cold gas that is trapped by a charged core interacts strongly with the gas. It produces a very excited atom-like particle that has very high energy levels, which causes strong interactions with thousands of other atoms. This work could lead to greater understanding in the work of condensates and superconductors. However it seems to hold promise in allowing effective imaging of an electrons wave function.

Graphene Super-Conductors

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In my last article I wrote about Graphene, providing back ground knowledge and how it could be used in space crafts as a final-stage propulsion system; you can read the article HERE. Since then I did a bit more research and found out scientists have moved a step closer to possible Graphene Super-Conductors.

I wont go into great depth about the nature of Graphene as I have already written about that, but remember that due to structure it has very good electrical conductive properties. The Graphene is a single sheet of Carbon 1-atom thick, by stacking two sheets that twist away from each other with a "magic angle" of 1.1 degrees unusual super-conductive properties have been observed. At a critical temperature of 1.7 degrees Kelvin this structure exhibits super-conductivity, where there is zero resistance to electrical flow. This material is the first pure Carbon super conductor achieved using Graphene, although the temperature is much lower than room temperature it still shows promising signs for the development of SCs. It achieved a record for carrier density, which is basically how many electrons can be carried in a certain volume, it results in powerful transmission of electric. Further investigation are made easier due to the material being easily tuned allowing for a variety of controlled experiments, which provides a useful tool for trying to produce high-temperature super conductors.

There are suggestions to apply pressure to the structure with the expectation to increase the critical temperature at which it becomes super conductive. I am sure you agree that such pioneering studies are very exciting, and the advancement of superconductors is gaining speed. Hopefully within the next decade, with the help of studies like this we will achieve superconductors that operate at high temperatures. This advance our technological capabilities greatly, allowing nano fibres to carry large quantities of electric without getting hot.

Google's 72-Qubit Chips

The race for Quantum Computing supremacy is hotting up between IBM and Google, with Google packing quite a punch lately. They have developed a 72-Qubit quantum processor and named it Bristlecone. When using qubits in a quantum processor it is subject to some error, but by increasing the number of qubits the error rate can be decreased.

Google states:

We can assign a single system error by applying random quantum circuits to the device and checking the sampled output distribution against a classical simulation. If a quantum processor can be operated with low enough error, it would be able to outperform a classical supercomputer on a well-defined computer science problem, an achievement known as quantum supremacy.
Source

Theory suggest that "quantum supremacy" can be achieved when using 49 qubits. So Bristlecone having 72 seems to stand a good chance in reducing the error rate low enough to obtain quantum supremacy, if it can achieve this it will outperform well known super computers. Such quantum processors and supercomputers use superconductors so that there is a minimal loss in information when processed, and to speed up the transmission of electrical signals.

Image Credit:- wikimedia

Bloch sphere: The polarisation state exactly 0 is at the top-pole, and exactly 1 is at the bottom-pole, there is infinite combinations in between.

Some quick theory to help you understand a qubit now. Particles like photons have polarisation, either 0 or 1, when you measure the polarisation you observe either 0 or 1 (don't confuse this with a binary bit like on/off). A qubit is a super position of of 0 and 1, with different weighting associated with wither observable. A useful tool to help you understand this is the Bloch sphere pictured above, the qubit state is labelled with , you will notice it is between either poles assocaited with the polarisations. can take an infinite number of positions on that sphere. It's this capability of the qubit superposition that lends to a possible infinite amount of states. Although they do not use infinite states it's this feature of multiple superposition that leads to quantum processing abilities.

Conclusion

Technology advancements are happening more often at a faster rate, we live in an exciting time. Maybe we are on the brink of achieving computing capabilities able to transform our lives, with quantum processors advancing and the progress in super conductivity research. The use of lasers are vast and now show the ability of moving atoms around fast enough and accurately enough to produce holograms, there are also invaluable in the study of the BEC and super conductors.

If you didn't notice the connection, it is the advancement of computing capabilities. Lasers allow us to cool atoms to create the Bose-Einstein condensate, which was mentioned with the giant-atom. The BEC is an invaluable area when it comes to understanding super conductivity, which will ultimately allow for smaller transistors and greater classical computing power. Quantum processors use superconductors in their implementation in order to process electrical information more effectively.

I hope you enjoyed this article, let me know what you think, give me some feedback, leave your comments. Until next time........

@physics.benjamin

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References:

3D holograms

https://link.springer.com/article/10.1007%2Fs13319-017-0122-2
Nature
Nature
Holography

Graphene

Unconventional superconductivity in magic-angle graphene superlattices

Giant atoms

Coupling a single electron to a Bose–Einstein condensate: Nature

Google's Bristlecone and Q.Computing

Quantum Computing
Google

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