Quantum-supremacy, translated as "quantum hegemony".
The concept of quantum supremacy actually has a long history, and later became popular after being popularized by an American theoretical physicist named John Preskill.
John Preskill first predicted that a computer with more than 50 qubits would be able to surpass all classical digital computers in dealing with certain problems, and by then it could be called the era of quantum supremacy.
However, when John Preskill saw the rapid progress of quantum computers today, he felt that what he said was a bit too full, so he changed it to a second level, that is: humans will be able to use it in the near future.
Noisy medium-scale quantum (nisq) technology.
If John Preskill came to Ye Hua's technology villa estate and saw this quantum computer in the underground library that already met DiVincenzo's five major standards, he would probably write an error-correction article and re-emphasize it.
The era of "quantum supremacy" has arrived.
The emergence of quantum computers will not instantly bring about earth-shaking changes to the world, but its role in the field of high-tech research and development is also immeasurable.
Ye Hua has already identified the top ten application scenarios of quantum computers.
[Digital Quantum Simulation and Analog Quantum Simulation] If Ye Hua wants to simulate the human gene array map, quantum simulation applications must be involved and are indispensable.
The other nine application scenarios are quantum optimizer, quantum hardware test platform, quantum annealing, anti-noise quantum circuit, quantum deep learning, quantum matrix inversion, quantum recommendation system, quantum semi-definite programming, and quantum acceleration.
Kitagawa Ayako, who had been watching for a long time, couldn't help but said curiously: "Quantum computers have been very popular in recent years. It seems that an American scientist said that a quantum computer with 50 to 100 qubits may be able to perform tasks beyond the capabilities of current classical digital computers.
Task, I read in the news that Google has achieved 72 qubits, why is yours only 64 bits..."
"Huh? Do you mean to look down on me? How dare you...I think you are in trouble!" Ye Hua suddenly looked at her with dissatisfaction.
"Yes, I have long wanted to have enough to eat all day long." Kitagawa Ayako looked at her with a smile, her every smile was charming and full of provocation.
Seeing her like this, the hook was too straight. Ye Hua didn't want to seize her properly. He looked away and said hehe, "What do those media people know? You are the only one who believes it. Google has achieved 72 qubits. Has quantum supremacy arrived?"
I haven’t heard from Google that they have carried out large-scale prime factorization?”
Kitagawa Ayako retorted: "How do you know? Maybe it has been done internally at Google? It's just for business confidentiality, just like you."
Ye Hua smiled calmly and said: "Google is a listed company. If there is such a big breakthrough, it will definitely announce the latest research and development results as soon as possible to increase the market value."
Seeing Kitagawa Ayako's speechless but pouty look, which seemed unreasonable and arrogant, Ye Hua wanted to persuade her, but after thinking about it, it seemed that it was not necessary.
She is not a professional in this field, and the science of quantum mechanics itself is mysterious. She can spend three days and three nights talking about any quantum branch with an expert, let alone a layman?
After Ye Hua confirmed that all the data and equipment were operating normally, he turned off all the holographic floating screens in front of him with a sweep of his hand, turned around and said to her: "Go and bring me the first aid medical kit."
Kitagawa Ayako didn't know what he wanted the medical first aid kit for, but she walked out of the basement to get it.
Looking at the direction in which she disappeared, Ye Hua withdrew his gaze and continued working.
For women, you may not be convinced, but you can be convinced.
As the saying goes, a river sinks with the sun, and as time goes by, it rises like the sun.
Speaking of the news that Google has achieved 72 qubits, most of it is the result of half-understood media, hype, or misleading. It can only deceive people who don’t know the truth, Preskill
The 50 to 100 qubits mentioned refer to qubits that can perform parallel operations at the same time, that is, quantum logic bits.
This involves a "quantum coding" problem, because all calculations using qubits are based on probability, and there is an error, so more qubits need to be sacrificed to correct errors.
The so-called "quantum coding" is also called "quantum error correction code", and the so-called 72 qubits of Google are only on the physical level. If you put each qubit there, you can put more, but if you can't perform logical operations, then you can put more qubits there.
More is of no use.
At the logical bit level, the 72 qubits developed by Google are equivalent to 9 logical bits. Because they need to be sent in groups of 8 for error correction, each group actually only has 1 logical bit.
Even so, the accuracy cannot reach 100%, because as long as the "quantum error correction code" is used, it means that the quantum computer developed by Google has not solved the fourth criterion of DiVincenzo, that is: there must be a way to solve effective decoherence.
The quantum computer now built by Ye Hua has met DiVincenzo's five standards and is a true quantum computer. These 64 bits refer to qubits that can perform parallel operations at the same time, corresponding to Google's
There are 9 qubits, while Google’s corresponding 72 qubits, and Ye Hua’s quantum computer has 128 qubits.
The number of qubits announced by imb is also large, but the actual number of logical qubits is only about 6.
Google uses a group of 8 to correct errors, and the accuracy is only about 70~80%, which is the fidelity of the logic gate. It must do this. In fact, the more error correction groups, the closer it is to the correct answer.
But it can never be guaranteed to be 100% accurate. This is a flaw. Among the current quantum computer research institutions around the world, no one can solve the flaw of decoherence except Ye Hua.
As for what the quantum computer developed by Ye Hua uses to make qubits, of course it uses a quantum two-state system, which uses two degrees of freedom of a photon to make two qubits.
64 qubits are 64 photons, which is 128 qubits, and they are entangled with each other. The term is called ghz state, which is a special kind of quantum entanglement.
It is actually a very difficult period to use multi-quantum GHZ states. Ye Hua used 64 photons and used the two degrees of freedom of the momentum and orbital angular momentum of these photons to complete the preparation and preparation of 128 qubit GHZ states.
representation.
In fact, many European and American physicists believe that using linear optics to build a quantum computer is unworkable, that is, directly using the polarization, angular momentum, and orbital angular momentum of photons to create qubits.
But Professor Pan Jianwei’s team was the first to achieve the preparation and characterization of ghz states using the three degrees of freedom of photons’ polarization, momentum and orbital angular momentum.
Ye Hua directly completed the preparation and characterization of the ghz state with two degrees of freedom.
As for why it is said to be difficult and impossible to achieve, it is because it is too difficult to integrate, and an experiment requires a lot of equipment to ensure the coherence and lifespan of photons.
In fact, this is indeed the case.
In the basement of the villa, the quantum computer developed by Ye Hua is extremely large and consumes a lot of equipment and resources to ensure the coherence and lifespan of light quanta.
Photons are very fragile, and a single photon can be absorbed wherever it hits. Therefore, it is almost impossible to make thousands of qubits and achieve integrated miniaturization with the existing technical means and materials.
Failure to integrate means that it cannot be popularized for civilian use.
Ye Hua actually has a way to protect the coherence and lifespan of photons, and that is to solve the problem through "fields", but he has not done so now, which will consume more of his time and energy to make breakthroughs in new technologies.
Preparation of materials, etc.
He has not forgotten why he started doing this in the first place, which was just to simulate his own genetic array, obtain a complete genetic map, and implement controllable mutations.
Now that a quantum computer is available, that's all. We'll talk about the future later.
Europeans and Americans think this is not possible, but Professor Pan Jianwei has found a different approach. If there are too many photons, it is difficult to integrate, but multiple degrees of freedom of one photon can be used to make qubits. This is the power of Professor Pan Jianwei.
This is not what Ye Hua wants to do most, he is just taking it a step further.
This method is indeed feasible, but the cost is a bit higher, but for Ye Hua, as long as he can do 50 to 100 calculations and be able to calculate, it is enough to build a quantum computer.
