First Quantum Network Has Been Established In Breakthrough Research
While entanglement between two devices has been demonstrated in the past, this marks the first case of three devices working as part of an entanglement network. At the end of last year, a monumental breakthrough was announced with the first case of long-distance, high-fidelity quantum teleportation. This was quickly followed by the creation of a cryogenic quantum computer chip, and even a hologram using quantum entanglement just after that. You could say it has been a pretty big few months for the eventual goal of a quantum Internet, which could theoretically change everything when it comes to computing speed, privacy, and capabilities. However, new research suggests that could be even closer than we think. In a study conducted by two institutions in the Netherlands, scientists have created the first quantum network using quantum entanglement, successfully connecting three devices together. The research could lay the groundwork for creating a large-scale quantum network, a dream for many scientists in the field. Their work was published in the journal Science.
“This is the first time a network has been constructed from quantum processors,” said lead author Ronald Hanson in an interview with Inverse. “A single direct link between two processors has been shown on many platforms in the past decade, but no network had been achieved.” A quantum computer differs from a traditional computer in one fundamental way: traditional computers use binary to process information, using two states of either ‘on’ (1) or ‘off’ (0), whilst quantum computers add a new and more interesting state called superposition, which is both ‘on’ and ‘off’. Normal binary snippets of data are called bits, but quantum information is stored in qubits. Simply adding one extra state to the equation adds a wealth of new possibilities, with massively increased data flow. However, transmitting qubits is no easy feat. To do so, scientists must utilize the concept of quantum entanglement. Quantum entanglement, put simply, is a state of two or more particles in which observing the state of one provides information about the other – these particles are ‘entangled’. For example, if one particle was excited and in the 'on' state, the other would note this and behave in a similar way.
This is useful in the rapid transmission of data because if two systems are entangled, data can be copied across and a network of systems can be created. In this study, a network of three nodes was set up, affectionately named Alice, Charlie and Bob. Using an extremely complex system of photon detectors and beam splitters within each node, the researchers were able to demonstrate remote entanglement between the three nodes, creating a quantum network. While entanglement between two devices has been demonstrated in the past, this marks the first case of three devices working as part of an entanglement network. The work marks an important milestone in that elusive dream of a quantum Internet – albeit, that likely won’t come soon. Quantum computing is still in its infancy and requires extreme amounts of power as well as a mess of wires that makes scaling an issue. It is, however, a landmark in what could soon be an Internet revolution.
Chinese team develops quantum processor with world's largest number of superconducting qubits
A schematic of a two-dimensional superconducting qubit chip. /Photo from the website of the University of Science and Technology of China
A schematic of a two-dimensional superconducting qubit chip. /Photo from the website of the University of Science and Technology of China
Chinese researchers have made a new breakthrough in quantum computing technology.A group of researchers from the University of Science and Technology of China (USTC) have designed and fabricated a programmable superconducting quantum computer prototype with the largest number of functional qubits in the world – 62, and achieved two-dimensional programmable quantum walks on the system, according to the university.The study, led by renowned Chinese quantum physicist Pan Jianwei, was published in the top scientific journal Science on Friday. The computer prototype was named Zu Chongzhi after the accomplished Chinese mathematician from the fifth century. "Quantum walks are the quantum mechanical analog of classical random walks and an extremely powerful tool in quantum simulations, quantum search algorithms, and even for universal quantum computing," the authors wrote.They called their work a milestone that brings future larger scale quantum applications closer to realization on these noisy intermediate-scale quantum processors.
The development of quantum computers, which promise enormous computing advantages over classical computers, is one of the major challenges at the global scientific and technological forefront. It's also an area where developed countries are racing for leading technologies.With superfast parallel computing power in theory, quantum computers are expected to exponentially improve the efficiency of conventional computers in solving important social and economic problems in areas such as cryptography, big data optimization, material design and drug analysis.Superconducting quantum computing is one of the most promising candidates for scalable quantum computing. Its essential goal is to synchronously increase the number of built-in qubits and improve the performance of superconducting qubits, so as to exponentially speed up the processing of specific problems, which will eventually be applied in practice.
In 2019, U.S. tech giant Google developed a 53-qubit programmable superconducting processor, named "Sycamore," and claimed "quantum supremacy" – the point at which a quantum computer has outperformed any classical computer in the world.The 62-qubit Zu Chongzhi processor showed that China is at the same level as its U.S. counterparts in the field of superconducting quantum computing, Yuan Lanfeng, a research fellow at the Hefei National Laboratory for Physical Sciences at the Microscale of the USTC, told the Global Times. In December 2020, Pan's team established a quantum computer prototype named Jiuzhang, which the team said can process information 10 billion times faster than the 53-qubit quantum computer developed by Google. Read more: Tech It Out: What's under the hood of a quantum computer?
Quantum computing could be useful faster than anyone expected
With the right algorithms, even error-prone quantum devices could still be useful.
For most scientists, a quantum computer that can solve large-scale business problems is still a prospect that belongs to the distant future, and one that won't be realized for at least another decade. But now researchers from US banking giant Goldman Sachs and quantum computing company QC Ware have designed new quantum algorithms that they say could significantly boost the efficiency of some critical financial operations – on hardware that might be available in only five years' time. Rather than waiting for a fully-fledged quantum computer, bankers could start running the new algorithms on near-term quantum hardware and reap the benefits of the technology even while quantum devices remain immature. Goldman Sachs has, for many years, been digging into the potential that quantum technologies have to disrupt the financial sector. In particular, the bank's researchers have explored ways to use quantum computing to optimize what is known as Monte Carlo simulations, which consist of pricing financial assets based on how the price of other related assets change over time, and therefore accounting for the risk that is inherent to different options, stocks, currencies and commodities. Because of the vast spectrum of possibilities, this is one of the most compute-intensive tasks in finance, which requires making large numbers of predictions about different market movements. Quantum computing has long been identified as a potential avenue to speed up those risk assessments thanks to the extraordinary compute power that the technology is expected to bring about in comparison to classical approaches.
And many quantum algorithms exist already, which have been shown to increase the speed of Monte Carlo calculations by up to 1,000 times and could transform the way that financial markets operate – but only once those algorithms are deployed on to a quantum device that is capable of running the program, and of achieving accurate results. Previous work carried out by Goldman Sachs together with IBM, for instance, estimated that to achieve quantum advantage would require a device supporting 7,500 logical qubits. To compare, IBM is currently working on releasing a 127-qubit processor this year. It's not only a matter of counting qubits: for quantum computers to resolve calculations reliably, the devices will also have to be optimized to avoid errors. Current quantum processors have very high error rates, and according to QC Ware, it will be 10 to 20 years before the error-corrected quantum hardware that is necessary to efficiently run Monte Carlo simulations becomes available. "How can we cut the current timeline in half yet still get a significant speed-up?" ask the company's researchers in a blog post describing the new research. To achieve this objective, the team traded off some calculation speed in return for some hardware gains. The scientists designed two new quantum algorithms that slash the speed up from 1,000 times to 100 times – but they also require a shallower circuit size, which is expected to be available in the next five to 10 years. "The Goldman Sachs and QC Ware research teams took a novel approach to designing quantum Monte Carlo algorithms by trading off performance speed-up for reduced error rates," said Iordanis Kerenidis, head of algorithms at QC Ware.
"Through rigorous analysis and empirical simulations, we demonstrated that our Shallow Monte Carlo algorithms could result in the ability to perform Monte Carlo simulations on quantum hardware that may be available in 5 to 10 years." The speedup, although more moderate than that of other quantum algorithms such as the QFT-free Monte Carlo, is still significant; and according to the scientists, the method will effectively cut the timeline to usability in half. Goldman Sachs and QC Ware's efforts are reflective of an industry that is increasingly focusing on bringing about the benefits of quantum computing in the near term, despite the imperfections that are still holding quantum devices back. Whether it is by tweaking algorithms, combining quantum and classical techniques, or testing and comparing different approaches to quantum computing, researchers and companies are racing to crack the methods that will make quantum computers useful in as little time as possible. The two algorithms designed by Goldman Sachs and QC Ware, therefore, are yet another move towards the goal of finding quantum algorithms that are compatible with the noisy intermediate scale - NISQ – devices that are characteristic of current times.
