Mass production of Quantum Computers enabled by Silicon and Glass quantum chips

Rajesh Uppal March 15, 2022 Manufacturing, Quantum Comments Off on Mass production of Quantum Computers enabled by Silicon and Glass quantum chips 466 Views

The quantum computing market is projected to reach $65 billion by 2030, a hot topic for investors and scientists alike because of its potential to solve incomprehensibly complex problems.

Quantum computer development has been dominated by some of the biggest and most established IT players, in particular, Google, Intel, IBM, Microsoft, and Atos. Going strictly by the number of qubits – which, truthfully, is only one of several factors affecting quantum computing capability – Google appears to be furthest along, having recently announced a 72-qubit test chip. For its part, IBM has prototyped a 50-qubit quantum processor, which could be available to researchers and commercial clients via the company’s Q cloud before the end of the year. Meanwhile, Intel and its research partner, QuTech, have built a 49-qubit test chip. Rigetti announced it’s working on a 128-qubit chip, which it expects to have completed and available on QCS by August 2019.

Experts predict that quantum computers will be viable within a decade, however mass production would be feasible only in 20 years. Till then the distribution of quantum computing power will be via the cloud. Researchers are developing new approaches for mass production of quantum computers.

Low cost silicon microchips for mass production of quantum computers

Quantum computers could be mass produced at low cost with silicon microchips that have large-scale waveguides, optical tracks, for photons, instead of circuits for electrons controlled by transistor switches. These silicon photonic chips could solve two challenges for quantum computing, low-cost, high quality production methods and creating a reprogrammable computer. Silicon chips’ manufacturing methods are well proven and chips with large-scale optical waveguide tracks will enable mass production of quantum processors.

The silicon quantum processor works by guiding its photons, packets of electromagnetic energy, along its large-scale waveguides and encodes them into quantum-bits of information called qubits. A qubit can be a one and a zero at the same time and it is this superposition quality that allows the simultaneous calculations that can outperform conventional computing.

“It’s a very primitive processor [our silicon photonic microchip], because it only works on two qubits, which means there is still a long way before we can do useful computations with this technology,” explains Xiaogang Qiang, who undertook the research while a doctoral student at the University of Bristol. He now works at the National University of Defence Technology in China. “What we’ve demonstrated is a programmable machine that can do lots of different tasks,” he adds.

Any task that can be achieved with two qubits, can be programmed and realised with the processor. This small device has more than 200 photonic components and can be used as a scientific tool for quantum information experiments to begin with. It was made with Complementary Metal Oxide Semiconductor, CMOS, compatible processes and the Bristol team programmed it to implement 98 different two-qubit operations. Qiang’s former colleague, Dr. Jonathan Matthews, said: “We’ve used this device to implement several different quantum information experiments using nearly 100,000 different re-programmed settings.”

Future photonic microchips with more qubits will be able to take advantage of quantum particles’ unique property of entanglement. This property links qubits, entangling them, at any distance, and this linking enables the simultaneous computing that makes these quantum machines faster than conventional electronics. For example, two qubits in superposition are entangled and together they can store all the possible combinations of their quantum states, resulting in four values; two ones and two zeros. As qubits are added, the number of combinations increases dramatically, for example, 20 entangled qubits can store more than a million values.

Matthews added: “We need to be looking at how to make quantum computers out of technology that is scalable, which includes technology that we know can be built incredibly precisely on a tremendous scale.” Matthews works in the University’s Quantum Engineering Technology Labs, which was launched in April 2015.

Quantum scientists demonstrate world-first 3D atomic-scale quantum chip architecture

UNSW researchers at the Centre of Excellence for Quantum Computation and Communication Technology (CQC2T) have shown for the first time that they can build atomic precision qubits in a 3D device – another major step towards a universal quantum computer.

UNSW scientists have shown that their pioneering single atom technology can be adapted to building 3D silicon quantum chips – with precise interlayer alignment and highly accurate measurement of spin states. The 3D architecture is considered a major step in the development of a blueprint to build a large-scale quantum computer. Scientists at the University of Bristol’s Centre for Quantum Photonics, leading an international collaboration, made the leap from glass-based circuits to silicon by developing quantum chips from the workhorse semiconductor material used to build electrical processors in all computers and smartphones.

“Using silicon to manipulate light, we have made circuits over 1000 times smaller than current glass-based technologies,” said Mark Thompson, deputy director of the Centre for Quantum Photonics. “It will be possible to mass-produce this kind of chip using standard microelectronic techniques, and the much smaller size means it can be incorporated into technology and devices that would not previously have been compatible with glass chips.”

The researchers, led by 2018 Australian of the Year and Director of CQC2T Professor Michelle Simmons, have demonstrated that they can extend their atomic qubit fabrication technique to multiple layers of a silicon crystal – achieving a critical component of the 3D chip architecture that they introduced to the world in 2015. This new research is published today in Nature Nanotechnology.

The group is the first to demonstrate the feasibility of an architecture that uses atomic-scale qubits aligned to control lines – which are essentially very narrow wires – inside a 3D design. What’s more, team members were able to align the different layers in their 3D device with nanometer precision – and showed they could read out qubit states with what’s called ‘single shot’, i.e. within one single measurement, with very high fidelity. “This 3D device architecture is a significant advancement for atomic qubits in silicon,” says Professor Simmons.

To be able to constantly correct for errors in quantum calculations – an important milestone in our field – you have to be able to control many qubits in parallel. “The only way to do this is to use a 3D architecture, so in 2015 we developed and patented a vertical crisscross architecture. However, there were still a series of challenges related to the fabrication of this multi-layered device. With this result we have now shown that engineering our approach in 3D is possible in the way we envisioned it a few years ago.” In this paper, the team has demonstrated how to build a second control plane or layer on top of the first layer of qubits.

“It’s a highly complicated process, but in very simple terms, we built the first plane, and then optimised a technique to grow the second layer without impacting the structures in first layer,” explains CQC2T researcher and co-author, Dr Joris Keizer. “In the past, critics would say that that’s not possible because the surface of the second layer gets very rough, and you wouldn’t be able to use our precision technique anymore – however, in this paper, we have shown that we can do it, contrary to expectations.” The team members also demonstrated that they can then align these multiple layers with nanometer precision.

“If you write something on the first silicon layer and then put a silicon layer on top, you still need to identify your location to align components on both layers. We have shown a technique that can achieve alignment within under five nanometers, which is quite extraordinary,” Dr Keizer says. Lastly, the researchers were able to measure the qubit output of the 3D device single shot – i.e. with a single, accurate measurement, rather than having to rely on averaging out millions of experiments. “This will further help us scale up faster,” Dr Keizer explains.

Towards commercialisation

Professor Simmons says that this research is a milestone in the field. “We are working systematically towards a large-scale architecture that will lead us to the eventual commercialisation of the technology. “This is an important development in the field of quantum computing, but it’s also quite exciting for SQC,” says Professor Simmons, who is also the founder and a director of SQC.

Since May 2017, Australia’s first quantum computing company, Silicon Quantum Computing Pty Limited (SQC), has been working to create and commercialise a quantum computer based on a suite of intellectual property developed at CQC2T and its own proprietary intellectual property. “While we are still at least a decade away from a large-scale quantum computer, the work of CQC2T remains at the forefront of innovation in this space. Concrete results such as these reaffirm our strong position internationally,” she concludes.

In March 2017 MIT Unveiled A Technique to Mass Produce Quantum Computers

Researchers have found a way to make the creation of qubits simpler and more precise. The team hopes that this new technique could, one day, allow for the mass production of quantum computers. Researchers from MIT, Harvard University, and Sandia National Laboratories unveiled a simpler way of using atomic-scale defects in diamond materials to build quantum computers in a way that could possibly allow them to be mass produced.

For this process, defects are they key. They are precisely and perfectly placed to function as qubits and hold information. Previous processes were difficult, complex, and not precise enough. This new method creates targeted defects in a much simpler manner. Experimentally, defects created were, on average, at or under 50 nanometers of the ideal locations.

The significance of this cannot be overstated. “The dream scenario in quantum information processing is to make an optical circuit to shuttle photonic qubits and then position a quantum memory wherever you need it,” says Dirk Englund, an associate professor of electrical engineering and computer science, in an interview with MIT. “We’re almost there with this. These emitters are almost perfect.” One of the main remaining hurdles is how these computers will read the qubits. But these diamond defects aim to solve that problem because they naturally emit light, and since the light particles emitted can retain superposition, they could help to transmit information.

The research goes on to detail how the completion of these diamond materials better allowed for the amplification of the qubit information. By the end, the researchers found that the light emitted was approximately 80-90 percent as bright as possible.

Construction of large scale practical quantum computers radically simplified

The mass production of quantum computers would need standardized production techniques, but also error and fault tolerance. In the real-world, technological developments need to operate in imperfect conditions; what can be successfully tested in a highly controlled laboratory may fail when presented with realistic environmental factors, such as the fluctuations in voltage from an electronic component or stray electromagnetic fields emitted by everyday electronic equipment.

A team of scientists, led by Professor Winfried Hensinger at the University of Sussex, have made a major breakthrough concerning one of the biggest problems facing quantum computing: how to reduce the disruptive effects of environmental “noise” on the highly sensitive function of a large-scale quantum computer.

While Quantum computing on a small scale using trapped ions (charged atoms) can be carried out by aligning individual laser beams onto individual ions with each ion forming a quantum bit. However, a large-scale quantum computer would need billions of quantum bits, therefore requiring billions of precisely aligned lasers, one for each ion.

Instead, scientists at Sussex have invented a simple method where voltages are applied to a quantum computer microchip (without having to align laser beams) – to the same effect. Professor Winfried Hensinger and his team also succeeded in demonstrating the core building block of this new method with an impressively low error rate at their quantum computing facility at Sussex.

“We’ve reduced the difficulty of building a quantum computer to the equivalent of building a classical computer. In a classical computer, you have transistors and they apply voltage to execute a classical logic gate,” Winfried Hensinger, professor of quantum technologies at the University of Sussex’s Ion Quantum Technology Group, told IBTimes UK.

“We use microwave radiation, bathe the entire quantum computer in microwaves, then we have local magnetic field gradients within the actual processing zones, and by applying a voltage, we shift the position of the ion so it either interacts with the global microwaves or not.” Professor Hensinger said: “This development is a game changer for quantum computing making it accessible for industrial and government use. We will construct a large-scale quantum computer at Sussex making full use of this exciting new technology.”

Japanese boffins try ‘token passing’ to scale quantum calculations

A Japanese team has published what it believes is a solution to the problem of scale. Quantum gates are complex creatures with many more components than their classical equivalents, so instead of trying to cram enough gates into a small space to perform calculations, the University of Tokyo proposal is to send photons around in a ring, re-using one gate to act on different photons in turn.

If need be, the light pulses can travel around the loop indefinitely, according to professor Akira Furusawa and assistant professor Shuntaro Takeda, who came up with the scheme, without losing the quantum information they carry. Because of this, the pair make a fairly bold claim: “This approach potentially enables scalable, universal, and fault tolerant quantum computing, which is hard to achieve by either qubit or CV [continuous variable – El Reg] scheme alone.”

The paper, published at Physical Review Letters and also available at arXiv (PDF), also notes that the scheme is compatible with existing quantum error-correction techniques. In a media release (here) Professor Furusawa says his team is working on automating the error-correction process. The release adds that his previous optical-based quantum computing system needed 6.3m2 and 500 mirrors and lenses, and could only handle a single pulse at a time.

Furusawa’s paper notes that the gate sequence is electrically programmed, making it fast, and it notes that “all the basic building blocks of our architecture are already available”, meaning the work should be replicable. Furusawa said in the canned statement: “We’ll start work to develop the hardware, now that we’ve resolved all problems except how to make a scheme that automatically corrects a calculation error.”

Scientists at University of Sussex have ‘tamed’ some disruptive environmental effects on quantum computers

The University of Sussex’s Ion Quantum Technology Group have managed to dramatically reduce the effects of such environmental “noise” affecting trapped ion quantum computers, reporting their findings in an article published on 1 November 2018, in the prestigious journal Physical Review Letters. It means the team is one step closer to building a large-scale quantum computer with the capability to solve challenging real-world problems.

Small-scale quantum computers currently in existence only contain a handful of quantum bits – components of quantum computers that store information and can exist in multiple states, also referred to as qubits. As such, current quantum computers are small enough to be operated in a highly controlled environment inside a specialized laboratory. However, such machines do not have the processing power required to solve complex problems because of the limited number of qubits.

When built, large-scale quantum computers will be able to solve certain problems that would take even the fastest super computers billions of years to calculate. In order to create a quantum computer that can solve such problems, scientists will need to increase the number of qubits, which in turn will increase the size of the quantum computer. The problem is that the more qubits that are added, the more difficult it becomes to isolate the computer from any realistic “noise” that would disrupt the computing processes.

Hensinger’s team of University of Sussex physicists have made a quantum computing breakthrough that is capable of mitigating some of these problems. They collaborated with theoretical scientist Dr Florian Mintert and colleagues from Imperial College London, who proposed a theory of how one might be able to solve this problem by manipulating the strange quantum effects in use inside a quantum computer. The theory allows – making use of the strange properties of quantum physics – the execution of quantum computations in such a way that changes in the initial operational parameters of the machine do not lead to a substantial change in the end result of the computation. This in turn helps to insulate the quantum computer from the effects of environmental ‘noise’.

Dr Sebastian Weidt, senior scientist in the Sussex Ion Quantum Technology Group, explains the significance: “Realising this technique may have a profound impact on the ability to develop commercial ion trap quantum computers beyond use in an academic laboratory.” The Sussex team went to work to see whether they could actually implement this theory. They used complicated radio-frequency and microwave signals capable of manipulating the quantum effects inherent in individual charged atoms (ions), to demonstrate this in practical experiments. Their implementation is based on microwave technology, such as that present in mobile phones. Following months of intensive work in the laboratory, the Sussex scientists have managed to make this new method a reality, experimentally demonstrating its capabilities to substantially reduce the effect of “noise” on a trapped ion quantum computer.

Prof Hensinger, Head of the Ion Quantum Technology Group at the University of Sussex – which last year unveiled the first blueprint for a large-scale quantum computer – says: “With this advance we have made another practical step towards constructing quantum computers that can host millions of qubits. Such machines are capable of solving certain problems that even the fastest supercomputer may take billions of years to calculate and be of great benefit to humanity; they may be able to help us create new pharmaceuticals; find new cures for diseases, such as Dementia; create powerful tools for the financial sector; be of benefit to agriculture, through more efficient fertilizer production, among many other applications. We are only starting to understand the tremendous potential of these machines.”

Hensinger’s group is now utilising this new technique as they put the final touches to a powerful quantum computer prototype that is currently in their laboratory at the University of Sussex. Hensinger says: “It’s now time to translate academic achievements into the construction of practical machines. We’re in a fantastic position to do this at Sussex and my team is working round the clock to make large-scale quantum computing a future reality.”

IonQ Delivers A New Architecture And Glass Quantum Computer Chip in Sep 2021

IonQ beat its technology roadmap projection by more than a year by demonstrating its ReconfigurableMulticore Quantum Architecture (RMQA). Reconfigurable refers to the system’s ability to move and combine smaller chains of ions into larger ion chains. This increases the computing power of the quantum processing unit. IonQ believes the EGT will eventually be able to support at least a triple-digit number of qubits on a single chip.

Multicore describes the future ability to do quantum information processing on multiple distinct chains (or “cores”) of qubits contained in a single EGT. Multicore operation in IonQ’s architecture is enabled by reconfigurability.

This technology should eventually allow IonQ to begin scaling large numbers of qubits. Moreover, IonQ has also delivered another chip technology ahead of schedule – RMQA will be implemented on a new quantum chip platform called Evaporated Glass Traps (EGTs). Previous traps were made using silicon chipmaking processes, but the company has now switched to an evaporated glass trap technology—a way of constructing micrometer-scale features in fused silica glass often used to make microfluidic chips. Its previous trap technology, the company says, could not have supported IonQ’s new quantum architecture, which is based on multiple chains of ion-based qubits. Ultimately, IonQ executives say, the glass chip’s reconfigurable chains of ions will allow for computers with qubits that number in the triple digits.

“The purpose of an ion trap is to move ions around with precision, hold them in the environment, and get out of the way of the quantum operation,” explains Jason Amini, who led the evaporated glass trap team at IonQ. The 3D glass and metal structure Amini’s team constructed does all three better than its previous chips could, Amini says. Stray electric fields from charge on the silicon-based chip could destabilize the ions’ delicate quantum states, reducing the fidelity of quantum computation. But the evaporated glass design “hides any material that could hold charge,” he says. The effect is a more stable trap that computes better.

Another advantage, Amini says, is that the trap could be shaped to “get out of the way” of quantum operations. In an ion trap computer the ions’ quantum states are manipulated by zapping them with lasers. “We have to bring a lot of laser beams over the surface,” says Amini. The glass chip is “shaped to allow lasers to come through and address the device.”

IonQ’s recent demonstration involved RMQA using 4 chains of 16 ions in an EGT Series ion trap chip. These ion chains were transported and merged into combinations of a higher-connectivity, 32-ion quantum computing core. In IonQ’s demonstration it works like this: The trap holds four separate chains of 16 ions in a line. Each chain can be moved into position to be manipulated by the lasers, altering their quantum state or entangling groups of ions so their quantum states are linked. “Each chain is, by itself, a quantum computer,” says Chapman. In addition, two chains can be brought together to form a core that allows entangling qubits across the chains (the reconfiguration part) until eventually all the qubits can be linked to perform big, complex quantum operations.

The EGT series chips are expected to support more chains. Each chain will increase the quantum computational power by a factor of 4000 or more. The following IonQ video demonstrates the process: