More than a decade ago, Chinese physicist Pan Jian-Wei returned home from Europe to help oversee research into some of the most important technology of the 21st century.
At a conference in Shanghai this summer, Pan and his team offered a rare peek at the work he described as a "revolution."
They spoke of the hacking-resistant communications networks they are building across China, the sensors they are designing to see through smog and around corners, and the prototype computers that may someday smash the computational power of any existing machine.
All the gear is based on quantum technology - an emerging field that could transform information processing and confer big economic and national-security advantages to countries that dominate it. To the dismay of some scientists and officials in the United States, China's formidable investment is helping it catch up with Western research in the field and, in a few areas, pull ahead.
Beijing is pouring billions into research and development and is offering Chinese scientists big perks to return home from Western labs. China's drive has sparked calls for more R&D funding in the United States, and helped trigger concerns in the Trump administration that some types of scientific collaboration with China may be aiding the People's Liberation Army and hurting US interests.
"The United States must be prepared for a future in which its traditional technological predominance faces new, perhaps unprecedented challenges," the Center for a New American Security wrote in a recent report about China's quantum ambitions.
Quantum technology seeks to harness the distinct properties of atoms, photons and electrons to build more powerful tools for processing information.
Last year, China had nearly twice as many patent filings as the United States for quantum technology overall, a category that includes communications and cryptology devices, according to market research firm Patinformatics. The United States, though, leads the world in patents relating to the most prized segment of the field - quantum computers - thanks to heavy investment by IBM, Google, Microsoft and others.
Helping oversee China's program is Pan, whom Chinese media call the "father of quantum." From his labs at the University of Science and Technology of China (USTC), in Shanghai and Hefei, the 49-year-old leads a team of 130 researchers. In 2017, the journal Nature named him one of "ten people who mattered this year," saying he had "lit a fire under the country's efforts in quantum technology."
Pan occasionally gives lab tours to President Xi Jinping, who takes a keen interest in his work, according to Chinese media. Pan is also overseeing plans for a new national lab for quantum research in Anhui province, which he said had drawn about $400 million in government funding.
At the Shanghai event, Pan illustrated his slide presentation with science-nerd jokes about Einstein and "Star Trek." In a nod to Schrödinger's cat - a 1930s thought experiment that helped define a quantum concept called superposition - Pan used images of a cartoon feline standing upright and lying flat on its back.
"As we all know, in our everyday life, a cat can only either be in an alive or dead state," Pan said, but "a cat in the quantum world can be in a coherent superposition of alive and dead states."
He was making the point that quantum particles, also known as quantum bits, differ fundamentally from the bits in today's technology. Existing computers and communications networks store, process and transmit information by breaking it down into long streams of bits, which are typically electrical or optical pulses representing a zero or one.
Quantum bits, or qubits, which are often atoms, electrons or photons, can exist as zeros and ones at the same time, or in any position between, a flexibility that allows them to process information in new ways. Some physicists compare them to a spinning coin that is simultaneously in a heads and tails state.
In his talk, Pan detailed how China is harnessing qubits to safeguard its communications from hacking - one of the fields in which China appears to have a lead over the West.
Pan and his team are aiming to launch a constellation of satellites and a nationwide fiber-optic network that use qubits to securely transmit information. An almost 1,300-mile fiber link connecting Beijing, Shanghai and other cities is already up and running. So is a satellite China launched in 2016, which has conducted several prominent experiments, including facilitating a hacking-resistant video conference between Beijing and Vienna.
When the network is complete, it could complicate US efforts to eavesdrop on China's government or military communications, some Western scientists say.
"I predict China will go black in two to three years - we won't be able to read anything," said Jonathan Dowling, a physics professor at Louisiana State University who spends part of the year as a visiting faculty member at USTC in Shanghai.
Others argue that even if China's network equipment is more secure, it could still be hacked by manipulating the humans running the system.
If the technology gains traction globally, China could be in a strong position to sell it, given the large number of patents its universities and companies have registered for devices and technology relating to quantum communication and encryption, according to Patinformatics.
Pan has credited Edward Snowden for motivating China's quantum research. The former National Security Agency contractor's revelations about NSA eavesdropping led China to pour money into developing more secure communications, Pan has said in published interviews.
Barry Sanders, a Canadian physicist from the University of Calgary, spends two to three months a year as a visiting professor at the USTC labs in Shanghai. He got the job through China's "Thousand Talents" program, which recruits Western scientists for teaching and research stints, and offers incentives to persuade Chinese researchers to return home from overseas.
Sanders said China's cultural differences can provide advantages in the lab.
"I have my Western way of doing things - freedom of thought, take risks," he said. In China, there is more emphasis on the common good, he said. "One guy spent two years really focused on how to prepare the lab room. You can assign people these tasks - they will do something that in our world would be seen as beneath us. But here they are supported and held in high esteem."
Pan received his doctorate from the University of Vienna in 1999 and conducted further research at the University of Heidelberg before moving home, along with several Chinese colleagues.
China's work on quantum technologies at the time was "relatively backward" and needed outside help, Pan said in an email. "Therefore, our team took the initiative to send students to top research groups abroad to learn related technologies," he said. "Fortunately, they later returned back to work in China."
Most of the Chinese researchers speaking at the Shanghai conference spent years studying overseas. Their slide decks were peppered with humorous references to Western pop culture and events. One featured a picture of President Donald Trump with the caption "Make SPDC Great Again" - a reference to an optical process whereby a photon splits in two. During a coffee break, one Chinese researcher's phone erupted in a ringtone from the TV show "Friends."
Their PhDs or postdoctoral credentials came from universities such as Stanford, the Massachusetts Institute of Technology, Cambridge and the University of Toronto, according to their biographies printed in the program.
While their talks didn't focus on military applications, much of the technology they're pursuing would have clear uses in both the commercial and defense realms, scientists say.
Quantum computers might someday be able to crack all existing forms of encryption. Quantum sensors could help the Chinese military track and target enemy troops with greater precision. The university where Pan works, USTC, has established several quantum-research partnerships with state-owned defense companies in recent years, with aims that include enhancing the combat capability of naval vessels, according to Chinese media reports cited in the Center for a New American Security paper.