Beijing, Oct. 23 (science and technology daily) -- in a paper published Wednesday in the British journal nature, Google demonstrated quantum hegemony -- a programmable quantum computer that has surpassed the fastest classical supercomputer. The quantum system took about 200 seconds to accomplish what a classical computer would need about 10,000 years to do. The review called the achievement a major milestone in quantum computing.
The concept of quantum computers stems from the study of reversible computers. Quantum computer is a kind of physical device that performs high-speed mathematical and logical operations, stores and processes quantum information in accordance with the laws of quantum mechanics. A device is a quantum computer when it processes and computes quantum information and runs quantum algorithms.
Pattern recognition is the strength of quantum computers. For it, our current encryption is just a thin layer of "window paper" that can be cracked in seconds. It can be said that the realization of quantum computer will pose a threat to today's information society. The potential overwhelming advantage of quantum computers lies in the special nature of the quantum itself. As we know, informatics is a basic subject under computer science. The smallest information unit is called "bit". In traditional computers, you rely on "bits" of information set to 0 or 1, with either a value of 0 or 1. The bits of a quantum bit, however, have a superposition state, meaning that the same bit of information can be 1, 0, or any combination of 1 and 0.
Quantum theory is "forced" by experiments to explain experimental phenomena that cannot be explained by classical theory. It is a discipline based on observable measurement. Therefore, quantum theory still has many "incurable diseases", which are far from being recognized and mastered by human beings. As Bohr, one of the founders, once said, "anyone who is not confused by quantum theory does not understand it." The lack of theory leads to two major engineering problems: first, quantum computer has an exponential error rate in addition to its exponential computing power. How to realize its error correction ability? Second, quantum is extremely sensitive to the outside world. Slight changes in the external environment will also lead to its "degradation" and the loss of its superposition state, and outstanding computing power will be out of the question. So they have to be completely insulated, and the current practice of using ultra-low temperatures to slow down the movement of atoms is quite uneconomic.
Some time ago, Google published a draft paper on NASA, declaring that "the 53 Quantum bit processor of Google's AI Quantum research group has achieved" Quantum hegemony. The most powerful supercomputer currently needs to spend 10,000 years of computation on the Quantum computer and only 200 seconds is enough ". But it wasn't long before the paper was retracted. "Quantum Supremacy," translated as Quantum Supremacy, first emerged in the MIT Technology Review's Review of the Google's rivalry with IBM for Quantum computing research.
(Picture Source：Baidu)
"If you read in the news that someone has succeeded in building a quantum computer, you'd better freeze your credit card immediately." So wrote an article published in April by the institute of physics of the Chinese Academy of Sciences. Because, under quantum computers, the encryption that protects it can be easily broken. What is a quantum computer?
As early as December, when the field of quantum computing was still in the race, a report from the national academy of sciences said that as quantum computers became possible, governments should prioritize potential consequences and prepare for threats to cybersecurity. Google CEO Sundar Pichai said in an interview: "what's really exciting about quantum computing is that the universe we live in follows quantum laws at the most fundamental level according to existing physical theories, so early applications of quantum computing can help us better understand how the universe works! The risks associated with developing new technologies are decidedly high, but some of them may be avoided by taking the "right path". One way to help us do this, he says, is through "uniform global governance and elaborate ethical protocols".
The error-correcting process developed by the research team can guarantee high arithmetic fidelity up to 99.99%. To test the system, the team designed a task to sample random Numbers generated by quantum circuits. For a classical computer, the difficulty of this task increases with the number of quantum bits in a quantum circuit. In the end, the quantum processor collected a million samples from the quantum circuit in about 200 seconds, compared with about 10,000 years for a sophisticated supercomputer.
One goal of quantum computing is to perform certain computing tasks exponentially faster than traditional classical computers. Achieving this requires overcoming many challenges, such as generating a large amount of computing space while keeping the calculation error rate low, and designing a benchmark that is difficult for a classical computer to handle but that a quantum computer can easily perform.
In an accompanying news & opinion article, the scientists commented that "for the world's leading supercomputer... Achieving quantum hegemony is undoubtedly a remarkable achievement. But the paper also points out that more work needs to be done before quantum computers can be put into practical use, such as implementing sustainable fault-tolerant operations.
The team from Google AI quantum and the university of California, Santa Barbara, described the technological advances that have been made to achieve quantum hegemony. They have developed a processor made up of 54 quantum bits that use quantum superposition and entanglement to increase exponentially the amount of computing space that a classical bit can achieve. Because one qubit doesn't work properly, the processor actually USES only 53 qubits.
