Tyler O'Neal, Staff Editor SYSTEMS

Sweden's quantum supercomputer project shifts up a gear

Knut and Alice Wallenberg Foundation is almost doubling the annual budget of the research initiative Wallenberg Centre for Quantum Technology, WACQT, based at Chalmers University of Technology, Sweden. This will allow the center to shift up a gear and set even higher goals - especially in its development of a quantum supercomputer.

"Quantum technology has enormous potential and it is important that Sweden has the necessary skills in the area. During the short time since the center was founded, WACQT has built up a qualified research environment, established collaborations with the Swedish industry, and succeeded in developing qubits with proven problem-solving ability. We can look ahead with great confidence at what they will go on to achieve," says Peter Wallenberg Jr, Chair Knut, and Alice Wallenberg Foundation.

Since 2018, Chalmers University of Technology has been managing a large, forward-thinking research initiative - the Wallenberg Centre for Quantum Technology, WACQT - setting Sweden on course to global prominence in quantum technology. The main project is to develop and build a quantum supercomputer, offering far greater computing power than today's best supercomputers.

During the first three years, the quantum supercomputer researchers within WACQT have focused first on making the basic building blocks of the quantum supercomputer - the qubits - work as well as possible, at a small scale. A milestone was reached last year when they managed to solve a small part of a real-world optimization problem with their well-functioning two-qubit quantum supercomputer. The cryostat cooling Chalmers University's quantum processor to close to abolute zero. CREDIT Johan Bodell/Chalmers University of Technology

Increases the quality of the hundred qubits

Now comes the time to significantly scale up the number of qubits, and increase the efforts on developing software and algorithms. At the same time, the entire research initiative is being scaled up, with Knut and Alice Wallenberg Foundation (KAW) deciding to almost double WACQT's annual budget, from SEK 45 to 80 million per year for the coming four years. The investment has previously also been extended from its original ten years to twelve and has now a total funding of at least SEK 1.3 billion including contributions from industry and the participating universities.

"It is very encouraging that KAW shows such great confidence in us. It strengthens WACQT's research program and gives us the opportunity to build an even better quantum computer. In terms of the number of qubits, the goal is still one hundred, but now we are aiming at one hundred really high-performance qubits," says Per Delsing, director of WACQT and Professor at Chalmers.

Calculations have shown that the performance of the final quantum computer will benefit more from increasing the quality of the individual qubits, rather than the total number of qubits. The better their quality, the more useful the final quantum computer.

With the increased funding, WACQT will, among other things, invest in improving the materials in the superconducting chips that constitute the qubits. Quantum states are extremely sensitive, and the slightest disturbance in the materials can impair performance. The qubits manufactured at Chalmers are already among the best in the world, so improving them entails moving the entire research field into new territory.

"These disturbances are extremely small. It requires research just to understand what they are and which are most common. We need to study the entire manufacturing process in detail and explore new ways to eliminate disturbances in the material," Delsing explains. Per Delsing, Professor in Physics and Director of Wallenberg Centre for Quantum Technology, Chalmers University of Technology. CREDIT Johan Bodell/Chalmers University of Technology

Will employ another 40 researchers

With the increased funding, the number of researchers working on the quantum supercomputer project can now be significantly increased. For example, a new team will be formed to study nanophotonic devices that can enable the interconnection of several smaller quantum processors into a large quantum supercomputer. Within the next two years, the research force will be expanded by 40 people, almost double the current amount. In the first step, fifteen new postdocs will be recruited.

"This is ambitious recruitment in a highly competitive niche area. But our hopes are high - through previous recruitments, we have attracted top talents both from Sweden and internationally. We have a unique interaction with the industry, extensive experience of superconducting circuits, and an amazing cleanroom facility," says Delsing.

"These are very exciting times in quantum computing. New steps are being taken all the time and the competition is rapidly increasing, with many countries making major investments. This investment will ensure that Sweden and Chalmers remain at the global forefront," Delsing says.

Italian researchers explore irradiating COVID-19 cough droplets with UV-C lamps

Tyler O'Neal, Staff Editor SYSTEMS

Using supercomputer numerical modeling of saliva droplets' diffusion produced by coughs, researchers in Italy explore deactivating COVID-19 virus particles via UV-C light

One of the primary ways the COVID-19 virus is transmitted is via airborne diffusion of saliva microdroplets, so it is paramount to find methods to kill the virus in airborne microdroplets.

The extreme confusion that abounded at the beginning of the pandemic about safe social distances, mask-wearing, and social behavior inspired Marche Polytechnic University researchers, who happen to be intrigued by saliva droplet diffusion, to search for answers and ways to help. In Physics of Fluids, Marche Polytechnic University researchers describe using a supercomputer to do numerical modeling of cough droplets irradiated by UV-C light: The red zone (from your chest down) is the area of highest risk, so while your face may only receive a few cough droplets, it is critical to wash your hands and keep them away from your face. CREDIT V. D'Alessandro, M. Falone, L. Giammichele, and R. Ricci

In Physics of Fluids, from AIP Publishing, Valerio D'Alessandro and colleagues describe using a supercomputer to do numerical modeling of cough droplets irradiated by UV-C light. They also report exploring the social distances required to prevent virus transmission.

The researchers zeroed in on the evolution of a saliva droplet cloud, accounting for the inertia, buoyancy, and weight of each droplet and its aerodynamic interaction with the environment.

"We are interested in the possibility of deactivating virus particles via UV-C light," D'Alessandro said. "So, we explored the interaction of saliva droplets with an external source of UV-C radiation, a lamp."

UV-C is a well-established germicidal technique because it interferes with virus RNA replication.

"UV-A and UV-B also kill germs and are present within the sun's rays, but with these, it takes 15 to 20 minutes to kill a virus," said D'Alessandro. "The sun's rays disinfect surfaces during the summer, which is one reason why transmission is reduced then, but it can't be used for real-time disinfection. That's why we decided to explore the effect of UV-C radiation on viruses."

The researchers' work addresses key points still not completely understood. First, they determined that 1 meter (3.2 feet) of social distancing is not completely safe to avoid virus transmission. This is particularly important because this is the social distancing rule in Italy and its schools.

"While 1 meter of distance can suffice in a one-on-one situation, you can still get hit with cough droplets from the chest down," D'Alessandro said. "It's necessary to avoid touching your eyes, nose, or mouth with your hands. We found 2 meters (6.5 feet) to be a much safer distance."

D'Alessandro and colleagues stress that the largest droplets travel about 1 meter. Over this distance, they discovered only smaller droplets, which transport a reduced amount of the virus.

"It's important to emphasize that these results were obtained without any background wind, and if this is present, the distance is almost doubled," he said. "So we need to wear face masks, especially when in close proximity."

They also found "it is possible to reduce the contamination risk by about 50% when irradiating saliva droplet clouds with UV-C radiation -- without providing a dangerous dose to people," said D'Alessandro. "This is critically important because disinfection systems based on UV-C are not always acceptable. UV-C kills the virus, but higher doses for humans can be dangerous."

High exposures to UV-C are known to cause skin and eye tumors.

"Our work helps correct the understanding of safe social distancing," said D'Alessandro. "Also, our computations can help to design new real-time disinfection devices based on UV-C that can reduce the risk of COVID-19 transmission and other viruses within particular situations, such as for supermarket cashiers or people in similar situations."

The article "Eulerian-Lagrangian modeling of cough droplets irradiated by ultraviolet-C light in relation to SARS-CoV-2 transmission" is authored by V. D'Alessandro, M. Falone, L. Giammichele, and R. Ricci. It will appear in Physics of Fluids on March 9, 2021 (DOI: 10.1063/5.0039224). After that date, it can be accessed at https://aip.scitation.org/doi/10.1063/5.0039224.

Toshiba's bleeding-edge FPGAs take fintech, logistics to new level

Tyler O'Neal, Staff Editor SYSTEMS

Multi-chip architecture points way to continued increases in performance of Toshiba's optimization supercomputer; potential to create a game-changing shift in complex financial transactions and robotics

Toshiba Corporation has announced a scale-out technology that minimizes hardware limitations, an evolution of its optimization supercomputer, the Simulation Bifurcation Machine (SBM), that supports continued increases in computing speed and scale. Toshiba expects the new SBM to be a game-changer for real-world problems that require large-scale, high-speed, and low-latency, such as simultaneous financial transactions involving large numbers of stock, and complex control of multiple robots. The research results were published in an academic journal. (a) Scale-out approach: improve computing performance by increasing the numbers of computing chips; (b) All-to-all connection type combinatorial optimization problems: all variables interact with each other.

Speed and scale are keys to success in industrial sectors as different as finance, logistics, and communications, all of which have to deal with a large number and make complex decisions in the shortest time possible. Aiming to bring higher efficiencies to these and other businesses, Toshiba has addressed combinatorial optimization problems by developing high-speed, high-accuracy algorithms and corresponding practical supercomputer solutions. The company recently announced the second generation of its simulated bifurcation algorithms, implemented on classical computers via a single field-programmable gate array (FPGA), that surpasses computers in obtaining optimal solutions for various combinatorial optimization problems at high speed.

Toshiba continues to pursue better performance of the SBM by installing more FPGAs in the supercomputer, an approach called scale-out in computer architecture and has successfully demonstrated the world's first simultaneous scale-out of computing speed and problem size for all-to-all connection type combinatorial optimization problems. At the heart of the technology is a partitioned version of the simulated bifurcation algorithm that enables multiple FPGAs to exchange information on variables with each other, and that triggers an autonomous synchronization mechanism in minimizing the communications overhead to an extent that does not affect overall performance (Figures 1 & 2). Toshiba's new scale-out technology: A new multi-chip architecture featuring a partitioned version of the simulated bifurcation algorithm (partitioned SB) and an autonomous synchronization mechanism.

Trials have shown that an SBM with a cluster of eight FPGA (Figure 3a) achieves computational throughput 5.4 times higher than an SBM with a single FPGA, and solve problems 16 times larger; and simulation results with a 64 FPGA SBM have demonstrated that the relationship between the computing speed and number of FPGA is exactly linear (Figure 3b), indicating that the technology can continue to increase the scale-out with the same effect.

The 8 FPGA SBM also obtains solutions 828 times faster than an implementation of simulated annealing (SA), a widely used optimization technique, demonstrating that the SBM makes much more efficient use of computational resources than the SA (Figure 4). Figure 3: (a) SBM with an 8-FPGA cluster. (b) scale-out effect / Figure 4: Comparison of the computing time on 8 FPGA SBM and SA.

Commenting on the application of the technology, Kosuke Tatsumura, Chief Research Scientist at Toshiba Corporation's Corporate Research & Development Center, said: "Fast computing speed, large computing scale, and low latency to provide solutions are the critical values the new SBM can offer to business. For example, we expect the financial industry can benefit if they can trade more stocks simultaneously, and robots in the logistic industry will perform better with zero-time-lag computation. We hope the new technology will take fintech and logistics to a new level."