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Room Temperature Quantum Entanglement in Semiconductor

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posted on Jul, 22 2016 @ 03:42 PM

We have demonstrated that a long conduction electron spin lifetime in metallic-like material made up of carbon nanospheres can be achieved at room temperature.

This material was produced simply by burning naphthalene, the active ingredient in mothballs.

The material is produced as a solid powder and handled in air. It can then be dispersed in ethanol and water solvents, or deposited directly onto a surface like glass. As the material was remarkably homogeneous, the measurements could be made on the bulk solid powder.

This allowed us to achieve a new record electron spin lifetime of 175 nanoseconds at room temperature. This might not sound like a long time, but it exceeds the prerequisite for applications in quantum computing and is about 100 times longer than that found in graphene.
In principal, this may provide an initial avenue to high-density qubit arrays of nanospheres that are integrated onto existing silicon technologies or thin-film-based electronics.

Source:, July 22, 2016 - Engineers just made a quantum computer chip work at room temperature.

Ooohhh! Graphene and carbon nanospheres! There was another use of CNT on diamond to make q-bits also at room temp story the other day as well (haven't posted; not sure where to post, here or the grapheme mega thread). That is great news! No crazy lens or lasers, just some burnt naphthalene to make same-sized nanospheres. And it is relatively cheap. Next up, build a logic gate or two, add some error correcting and you are almost there!

posted on Jul, 22 2016 @ 03:46 PM
As a side note, USC and Lockheed Martin now have an upgraded, 1,098 q-bit, D-Wave 2X computer.

USC News, July 21, 2016: World’s most powerful quantum computer now online at USC.

posted on Jul, 26 2016 @ 07:20 PM
Crazy new idea from Russia! Their thinking is: why make a bunch of qbits and deal with the hassle of keeping track of each one and the states? Why not 'slice' one qbit into multiple states? Crazy!

While traditional bits represent data as 0s or 1s, qubits are distinguished by what's known as superposition, or the ability to be both 0 and 1 at once.

Superposition is the heart of quantum computing's exciting potential, but it's also proved a thorny challenge. While calculations require that qubits not only maintain their state but also interact with one another, the quantum objects that have been used to create qubits -- ions or electrons, for example -- have so far only been able to maintain a certain quantum state for a short time. In a system with dozens or hundreds of qubits, the problem gets even trickier.

That's where physicists from the Moscow Institute of Physics and Technology and the Russian Quantum Center are proposing a different approach. Rather than trying to maintain the stability of a large qubit system, they sought instead to increase the capacity of the units doing the calculations. For that, they turned to the "qudit," a qubit alternative.
A qudit with four or five levels is able to function as a system of two 'ordinary' qubits, and eight levels is enough to imitate a three-qubit system," explained Aleksey Fedorov, a researcher at the Russian Quantum Center.

Source: PCWorld, July 25, 2016 - Quantum computing moves beyond 1s and 0s to make them easier to build.

Why have a pizza with 4 slices when you can have 12? Right? You are already doing the work to read the state so why not allow the "noise" between the quantum state to actually behave as a qbit itself? So, have 5 q-bits? Read the "in between states" as more states, and now, you have 25 q-bits!

Works on any true q-bit system just need some calibration to set the new levels! That is pretty cool there!

posted on Aug, 5 2016 @ 03:31 PM

The new module builds on decades of research into trapping and controlling ions. It uses standard techniques but also introduces novel methods for control and measurement. This includes manipulating many ions at once using an array of tightly-focused laser beams, as well as dedicated detection channels that watch for the glow of each ion.

The module performs these tasks using different colors of laser light. One color prepares the ions using a technique called optical pumping, in which each qubit is illuminated until it sits in the proper quantum energy state. The same laser helps read out the quantum state of each atomic ion at the end of the process. In between, a separate laser strikes the ions to drive quantum logic gates.

“By reducing an algorithm into a series of laser pulses that push on the appropriate ions, we can reconfigure the wiring between these qubits from the outside," he says. "It becomes a software problem, and no other quantum computing architecture has this flexibility."

The team believes that eventually more qubits—perhaps as many as 100—could be added to their quantum computer module. It is also possible to link separate modules together, either by physically moving the ions or by using photons to carry information between them., Aug. 3, 2016 - Programmable ions set the stage for general-purpose quantum computers.

The module holds 5 ion qbits via lasers which sounds like the MIT device (i.e., at room temperature). The article states they have a good old fashion database to store what the lasers need to do to perform calculations! So they step through the database table entries to manipulate the lasers and watch the qbits react. The marriage of the new with the future! The “programmable” portion is the news as most qbits are set up to perform a single algorithm. Now they can just reconfigure the qbits in a general manner!

That is pretty d@mn cool! And is a huge step towards a general purpose quantum computer.

posted on Sep, 1 2016 @ 05:28 PM

NREL's [National Renewable Energy Lab] scientists were able to observe the [optical Stark] effect quite readily at room temperature in materials grown using solution processing.

The NREL researchers used the optical Stark effect to remove the degeneracy of the excitonic spin states within the perovskite sample. An electron can have either "up" or "down" spins, and electrons with opposite spins can occupy the same electronic state. Circularly polarized light can be used to only interact with one of the spin states, shifting its transition energy.

The optical Stark effect possesses promising applications, including the potential to be used as an ultrafast optical switch. In addition, the optical Stark effect can be used to control or address individual spin states, which is needed for spin-based quantum computing., NREL discovery creates future opportunity in quantum computing.

This announcement is even better than the OP! Perovskite is a ceramic with a crystal structure. The thinking is to boost solar photo-voltaic cells efficiency using custom made perovskites. Which is why it was being studied at NREL. They just happened upon noticing the effect being evident. Then confirmed what they were seeing. The ability to set and read spin states at room temperature is a cool find! Just on a price scale between supercooling ions for entanglement and making a sheet of perovskite is huge. Then having the ability with tuned lasers to set and read bits without any need of cooling...

Neat find!

posted on Oct, 20 2016 @ 05:42 PM

The Stanford team has built what's called an Ising machine, named for a mathematical model of magnetism. The machine acts like a reprogrammable network of artificial magnets where each magnet only points up or down and, like a real magnetic system, it is expected to tend toward operating at low energy.

The theory is that, if the connections among a network of magnets can be programmed to represent the problem at hand, once they settle on the optimal, low-energy directions they should face, the solution can be derived from their final state…

Rather than using magnets on a grid, the Stanford team used a special kind of laser system, known as a degenerate optical parametric oscillator, that, when turned on, will represent an upward- or downward-pointing "spin."

Nearly all of the materials used to make this machine are off-the-shelf elements that are already used for telecommunications. That, in combination with the simplicity of the programming, makes it easy to scale up. Stanford's machine is currently able to solve 100-variable problems with any arbitrary set of connections between variables, and it has been tested on thousands of scenarios.

A group at NTT in Japan that consulted with Stanford's team has also created an independent version of the machine., Oct. 20, 2016 - Researchers create a new type of computer that can solve problems that are a challenge for traditional computers. article, A Coherent Ising Machine Based On Degenerate Optical Parametric Oscillators.

Wikipedia: Ising Model (algorithms applicable to this type of device are about half way down).

Wikipedia: NP Completeness (for some tough reading for the non-computer scientists out there!).

This announcement is very interesting as it is an alternate to true quantum computing (a general purpose quantum computer would be able to calculate the same results) but is also “quantum” in nature. Kind of like how the D-Wave annealing computer is “quantum” in its application. This is more so! Also it is at room temperature.

In essence, the machine is set up (programmed) with the magnetic “bits” being set by the lasers then being allowed to “run” until it reaches its lowest level magnetic state where the polarization of the magnets are “read” which is the optimal solution to the problem programmed in.

As stated in the article this is a small subset of problems that can be solved but what a subset! NP (non-deterministic polynomial) problems are defined by how long they would take on a Turing machine (typical computer). As the variables increase the amount of time to calculate a solution grows (typically exponentially). The classic introduction to NP algorithms is the Travelling Salesman where a salesperson has to take one circular path while visiting specific cities only once. Each city added creates new complexity which becomes difficult for current computers to solve.

The fact that this Isisng machine was re-created by NTT is very significant! It is one thing to create a device to solve a problem using new technology but to have that work verified at the same time is a real success!

posted on Oct, 20 2016 @ 06:30 PM
Update on University of Chicago, Institute for Molecular Engineering and what they have achieved. I do not think this is the same device as the OP but is cool none the less.

“Quantum coherence underlies all quantum information technologies, such as quantum communication and quantum sensing. However, the coherence time in materials is eventually limited by the magnetic noise produced by the fluctuating nuclear spins in a crystal,” said Hosung Seo…

However, spin qubits in silicon carbide have been expected to have inherently short coherence times because of the high concentration of magnetic nuclei in the crystals. Counterintuitively, the electron coherence time in silicon carbide reaches 1.3 milliseconds—the longest time measured in a naturally isotopic crystal.

“Our work has important implications beyond silicon carbide. The essential physics and the dynamics responsible for the coherence found in silicon carbide, a binary crystal, may allow qubits in ternary and quaternary crystals to have even longer spin coherence times,” said Abram Falk.

Source: University of Chicago, Institute for Molecular Engineering, Oct 13, 2016 - Exceptionally robust quantum states found in industrially important semiconductor., press release: Exceptionally robust quantum states found in industrially important semiconductor. Quantum decoherence dynamics of divacancy spins in silicon carbide (paper accepted for publication)

Turns out there are two forms of silicon carbide that form during the manufacturing process. So they had one chip specifically made for them with one form mainly. That is where the noticed the increased coherence times.

The “binary crystal” is just a crystal made of two compounds. So when they make a crystal with three or four elements they expect the coherence time to increase. It is thought that the time coherence needs to last 10 – 100 microseconds (0.1 milliseconds) for a practical quantum computer so it looks like they have busted through that barrier (1.3 milliseconds is 1,300 microseconds). Add to that this is basically off the shelf material… seems like quantum computing is coming along rather nicely!

posted on Oct, 25 2016 @ 06:48 PM

"Typically, for surface electrode traps, the laser beam is coming from an optical table and entering this system, so there's always this concern about the beam vibrating or moving," said engineer Rajeev Ram. "With photonic integration, you're not concerned about beam-pointing stability, because it's all on the same chip that the electrodes are on. So now everything is registered against each other, and it's stable."
The team’s successful demonstration of their prototype suggests that large-scale trapped-ion quantum systems could employ similar techniques. However, one remaining barrier is that the integrated photonic system has no mechanism for varying the amount of light delivered to the ions. The researchers are investigating the addition of light modulators to the gratings in order to address this issue., Oct. 25, 2016 - Protoype Photonic Chip Shines a Light on Practical Quantum Computing.

I think this is the MIT team. Did a quick google for one of the researchers mentioned and it matched to "MIT staff" page. Earlier they said they were going to start working on doing just this--integrate the lasers onto the same chip as the ion traps being used. So that sounds like a good win for them! They have a prototype up demonstrating the concept. Now it looks like they need a laser to set the qubit and scale up the number. So that is two months before a demonstration and review from their initial announcement. That is good progress!

[ETA: Yes, it is the MIT team. MIT New, Aug. 2016 - Toward practical quantum computers from previous post.]
edit on 25-10-2016 by TEOTWAWKIAIFF because: grammar nazi

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