on May 3rd, the two quantum computing prototype, the prototype by USTC, - alibaba quantum computing lab, zhejiang university, Chinese academy of sciences, institute of Chinese academy of sciences and other units or companies jointly developed.Although there is a media of the technology achievement as "reading China quantum computer, than a great power, the light of the taihu lake is badly?"The title of the class.But with the aim of technological achievements, from truly universal standard quantum computer is still a long way to go, this release of two prototype, is only a small step in China's research and development of quantum computing.

jian-wei pan, professor at the press conference on May 3,

# ** what would happen to the two quantum computer performance **

the first prototype to see light quantum computing.According to the Chinese academy of sciences academician jian-wei pan, the team for the first time in 2016, ten entangled photons manipulation, on the basis of building the light quantum computing prototype, the prototype of the bose sampling 24000 times faster than the industry.By comparing and found and classic algorithms, this light quantum computing prototype machine than humans first vacuum tube computer (ENIAC) and the first transistor computer (TRADIC) speed increase 10 to 100 times.

from member of jian-wei pan can be found in the expression of this light quantum computing prototype machine is based on linear optics, quantum dots as single photon source to use, and can implement 10 entangled photons manipulation.This result has been more than the United States keep track of nine quantum bit manipulation.

released from the point of view, the structure of the lower right corner of the picture is a quantum dot single photon source, wrapped in a temperature of liquid helium containers, also is the picture on the right side of the cube and cylinder combined into "big pot".The most the right side of the small pillars is magnified the appearance of a quantum dot system, is in the midst of a pillar of microcavity semiconductor growth a indium arsenic quantum dots.After single photons emitted is collected through the single photon switch input to the calculation in the light path, and then the calculation results through the detector counts, again after signal processing can be obtained.

bose sampling is complicated to explain, this process can be understood as a poisson sampling quantum simulation of the development of quantum computer scientists are interested in this question, because this is a # p - Hard questions, is much more difficult than NP - Hard problem, and NP - Hard problem is a kind of NP problem inside the hardest, NP problem refers to has not been proved whether there is a polynomial algorithm to solve the problem, visible bose sampling is more difficult for classical computers.

single photon operation

look from the purpose, this light quantum computing prototype machine must be a special machine, rather than general machine - bose can only be used for sampling.And this light quantum computing prototype machine in terms of "bose sampling" run 24000 times faster than their international counterparts, with the human first vacuum tube computer (ENIAC) compared to the first transistor computer (TRADIC), running speed increased by 10 to 100 times.

in sure this light quantum computing prototype machine in terms of "bose sampling" run 24000 times faster than their international counterparts at the same time, also need to be awake to recognize that this light quantum computing prototype machine is the first human to mark vacuum tube computer (ENIAC) and the first transistor computer (TRADIC), two machines run faster than that of 10 to 100 times.Its performance is limited, some media with great power, the light of the taihu lake for reference, this kind of practice is not in order.

10 superconducting quantum bits of entangled state

based on the linear equations of superconducting quantum processor demo

look at another one of low-temperature superconducting system prototype.This quantum computing prototype machine is also implemented 10 quantum bits, quantum computing prototype and and light, also a machine, can only be used for solving linear equations.Although there is no the other low temperature superconducting system prototype, but should also is similar to the existence of ENIAC and TRADIC - performance and generality, but it is a small step in the domestic field, thus has significance.

# ** objective evaluation of China's prototype quantum computing **

before mentioned, the two quantum computing prototype machine is used for solving linear equations, and bose sampling machine, and performance relative to the very mature classical computers now are more general.But, after all, also don't have to be modest, quantum computer compared with classical computers huge advantage.

quantum computing is the advantage of the characteristics of the quantum superposition and entanglement achieved excellent parallel computing ability.With N quantum state of a quantum computer operation is tantamount to an evolution of completed 2 NTH power of data parallel processing, which makes a quantum computer compared with classical computers in advantage.Especially in super parallel computing ability, the advantages of quantum computer is particularly outstanding.

the first in the world beyond the early classical computers single photon quantum computer

as birth although weaker, but as a result of quantum computers have greater development potential, and relative to the classic computer now so can't use two prototype in the flaw and performance and commonality struck down.

in addition, we also cannot be proud.Can't because of the success of the two quantum computing prototype and ignoring technological progress abroad.

in 2012, for example, r. j. Schoelkopf in superconducting lines of three bits in the quantum error correction coding.In 2015 John m. Martinis in superconducting lines nine bits of quantum control is realized.The Chinese independent research and development of 10 quantum bit low temperature superconducting quantum computing prototype, it was broke John m. Martinis in 2015.From a macro point of view, the two countries in the research and development of quantum computers might represent lead alternately.

in addition to the low temperature superconducting system, there are still a quantum dot system, ion trap, topological quantum computing research direction.However, due to the low temperature superconducting system and quantum dot system has good expansibility, more suitable for industrialized production, so the two direction as the main direction of researchers.The low temperature superconducting system and quantum dot system, low temperature superconducting system researchers and researchers more than quantum dot system.

xiao-bo zhu, a professor at the university of science and technology of China is flexing superconducting quantum bit processor chip

a big direction of quantum dot system is the semiconductor quantum dot, such as Intel is very keen to study silicon-based semiconductor quantum chip, one reason is that Intel want to use their some mature technology in the field of silicon chips.Abroad at the university of new south wales has implemented two qubits silicon-based semiconductor quantum chip of news.

in semiconductor quantum dots, the preparation of single quantum dots around the year of 2010, realize double quantum dots in 2011, in 2012-2013 to realize two single quantum bit, quantum dots coding in 2014-2015 to realize four two quantum bit, quantum dots encoding in 2016 have six quantum dots to three qubits, and implements the three bits of quantum gate operation.In China continued to make progress at the same time, foreign is still stay on two of four quantum dots coding bits, China has reached the international leading level in the sector.

however, in order to realize quantum computation, not only to have enough physical bits, and form processing redundant logic bit by doing it, must have a high enough precision of logic gates, single bit logic gate and double bits logic gate need to be able to meet the threshold of the quantum computing precision.Bit more than 30 when logic, and has a high enough precision of logic gate, to produce comparable to or beyond the classical computers calculate the performance of a quantum computer.