"Quantum computers explained"


"So a quantum computer sets up some qubits, applies quantum gates to entangle them and manipulate probabilities, then finally measures the outcome, collapsing superpositions to an actual sequence of 0s and 1s."





Posted 2016-08-19:

First Quantum Sattelite launched by China


China has launched the world’s first quantum satellite go.nature.com/2auztJW pic.twitter.com/DlTWL8hBql





Meet the physicist behind the world’s first quantum satellite, successully launched today go.nature.com/2buZ0jD






Moving mentor-student story behind China Quantum Satellite. A parallel lab race evolves to collaboration.


Excerpts and notes from Nature article at this link


Chinese graduate says: “I was obsessed with these quantum paradoxes.” “They distracted me so much that I couldn't even study other things.”


Quote from article: "The natural progression for budding Chinese physicists in Pan's position was to study in the United States — so natural, in fact, that fellow students joked that their university's acronym, USTC, actually stood for 'United States Training Centre'. But Pan wanted to learn from a quantum experimental master. And for him, one physicist stood out: Zeilinger.”


So he goes to Austria.


“At their first meeting, Zeilinger asked Pan what his dream was. “To build in China a world-leading lab like yours”.


Pan completes his studies and goes back to China in 2001.


“By the time Pan returned to China in 2001, the potential for quantum-based technologies was recognized enough to attract financial support from the Chinese Academy of Sciences and the National Natural Science Foundation of China.” “The lucky thing was that in 2000 the economy of China started to grow, so the timing was suddenly right to do good science,” Pan says. He plunged into building his dream lab.”


In the years that followed the labs of mentor and student do a parallel race. They become rivals. They then want to try satellites. Mentor approaches ESA with no luck, student approaches Chinese space agency and gets approval. But he cannot do this alone.


“Ultimately, teleporting to a satellite is too big a task for any single group to do alone”.


Therefore mentor is approached.


Quote: “Although the promise to push forward the technological frontier has been the main attraction for the Chinese government, many physicists find the satellite project tantalizing for other reasons. “As a scientist, what drives me is learning more about the foundational side of physics,” says Chen. (End of quote)







Entaglement and Superconductor Cooper Pair Splitter by @Physique_ENS


Electron buddies (Cooper pair) stick together! Keep one in Paris,take the other to Los Angeles: they'll be connected!



[DOC] Let’s talk about quantum mechanics with Takis Kontos from @Physique_ENS ! #Physics ▶️youtu.be/mtA4ci3gdrY




A Cooper pair splitter- Carbon nanotube (crystal) that traps each of the two electrons of the pain from a superconductor and measures/manipulates its spin



(ENS - Ecole Normale Supérieure: Best FR University - Among Top20 Universities for Europe 2016 by Times Higher Education)





Captures from the video













Quantum entaglement




Experimental evidence of quantum entaglement


Our round-up of the science events that shaped 2015 ow.ly/Ws7hd pic.twitter.com/hk5NueOx8S


Excerpt: "Einstein also made headlines in August when physicists presented the most convincing proof yet that two objects, such as subatomic particles, could be linked, or ‘entangled’. This would allow one particle to influence the behaviour of another, even if the two are widely separated. Researchers showed that they could produce a robust entanglement between two electrons placed 1.3 kilometres from each other.


Einstein famously despised this phenomenon, which he called ‘spooky action at a distance’, because it seemingly broke the universal rule that nothing can travel faster than the speed of light. Despite Einstein’s misgivings, the approach could one day be used to build a highly secure quantum Internet that is immune to hackers."




Some notes


“Entanglement is the essential ingredient that knits space-time together into a smooth whole.”

“Ultimately, he found, reducing the entanglement to zero would break the space-time into disjointed chunks, like chewing gum stretched too far.”

Quantum entanglement as geometric glue — this was the essence of Van Raamsdonk’s rejected paper and winning essay, and an idea that has increasingly resonated among physicists.

Tensor networks, for example, are a technique developed by condensed-matter physicists to track the quantum states of huge numbers of subatomic particles. Brian Swingle was using them in this way in 2007, when he was a graduate student at the Massachusetts Institute of Technology (MIT) in Cambridge, calculating how groups of electrons interact in a solid material.