"At first, our road was very hard, but now our progress is faster and accelerating. It heralds the coming of a key period in the development of quantum computing. This is like bamboo shoots popping up after the rain," Pan says.
Due to the enormous potential of quantum computing, Europe and the United States are actively collaborating in their research. High-tech companies, such as Google, Microsoft and IBM, also have massive interests in quantum computing research.
The photon-based system is just one of the means scientists are trying to achieve quantum computing.
USTC Professor Zhu Xiaobo, who is researching superconducting quantum computing, says there are at least seven or eight different technical routes. Several Chinese research teams are on different roads.
"Nobody knows which route could eventually lead to a quantum computer of practical value. Maybe all roads lead to Rome. Maybe there will be different kinds of quantum computers to solve different problems. There is another possibility that a dark horse from an unknown road reaches the goal first," Zhu says.
The research team led by Pan Jianwei is exploring three technical routes: systems based on single photons, ultra-cold atoms and superconducting circuits.
Although Pan's team has an advantage in photon-based system, Pan says a system based on ultra-cold atoms might be the first of practical value.
In addition, the superconducting system, with its integration and coherence, cannot be ignored, says Pan. High-tech companies, such as Google and IBM, have made large investments in this field.
Pan estimates that Chinese scientists could realize manipulation of around 50 quantum bits to construct a superconducting quantum computer that can exceed the most powerful supercomputer by 2020.
ANOTHER "BABY"
In another lab of the Institute for Quantum Information and Quantum Technology Innovation, a superconducting quantum computer is under incubation.
Unlike the photon quantum computer displaying all its "organs" on the table, the superconducting quantum computer "baby" hides its key parts in a big cylinder more than a meter tall. The cylinder keeps the superconducting quantum chip at a temperature of minus 273.13 degrees centigrade.
Zhu Xiaobo, one of its main developers, and his colleagues have broken a record set by the research team from Google, NASA and the University of California at Santa Barbara, who achieved high-precision manipulation of nine superconducting quantum bits in 2015. The Chinese team independently developed a superconducting quantum circuit containing 10 superconducting quantum bits.
Holding a superconducting quantum chip as big as a nail, Zhu says the most difficult thing is to increase the control accuracy of the chip.
Although the team developed the chip, Zhu says the system cannot be called a superconducting quantum computer. "A quantum computer is totally new. Many top scientists are uncertain how a quantum computer will work."
He hopes to construct a prototype superconducting quantum computer with 10 quantum bits by the end of this year.
Pan reckons Chinese scientists could realize manipulation of 100 quantum bits within 10 years, which means the capacity of one quantum computer would be a million times the total capacity of all the computers currently in use.
Will everybody have a quantum computer in future?
Pan predicts there will be tens of thousands or millions of quantum computers in the world. "But I don't need one at home, as it's very difficult to make my mobile phone or laptop extremely cold. But I can use cloud technology to send tasks to the quantum cloud platform," says Pan.
"We don't need a quantum computer to do what traditional computers can do well. We need it to solve problems that are difficult for traditional computers, such as code cracking, weather forecasting and pharmaceutical design. Quantum computing will also push the development of artificial intelligence," he says.
"We still don't know if quantum computers will enter common use. Maybe future quantum computers will be totally different from what we imagine today."
