It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
UK Scientists make major breakthrough in developing practical quantum computers that can solve big challenges of our time
Universal of Sussex and Universal Quantum scientists have, for the first time, connected quantum microchips together, like a jigsaw puzzle, to make powerful quantum computers and with record breaking connection speed and accuracy
IMAGE: GRAPHIC SHOWING TWO QUANTUM COMPUTER MODULES BEING ALIGNED SO THAT ATOMS CAN TRANSFER FROM ONE QUANTUM COMPUTER MICROCHIP TO ANOTHERview more
CREDIT: UNIVERSITY OF SUSSEX
Researchers from the University of Sussex and Universal Quantum have demonstrated for the first time that quantum bits (qubits) can directly transfer between quantum computer microchips and demonstrated this with record-breaking speed and accuracy. This breakthrough resolves a major challenge in building quantum computers large and powerful enough to tackle complex problems that are of critical importance to society.
Today, quantum computers operate on the 100-qubit scale. Experts anticipate millions of qubits are required to solve important problems that are out of reach of today’s most powerful supercomputers [1, 2]. There is a global quantum race to develop quantum computers that can help in many important societal challenges from drug discovery to making fertilizer production more energy efficient and solving important problems in nearly every industry, ranging from aeronautics to the financial sector.
In the research paper, published today (from 10:00 GMT, Wednesday 8 February 2023) in Nature Communications, the scientists demonstrate how they have used a new and powerful technique, which they dub ‘UQ Connect’, to use electric field links to enable qubits to move from one quantum computing microchip module to another with unprecedented speed and precision. This allows chips to slot together like a jigsaw puzzle to make a more powerful quantum computer.
The University of Sussex and Universal Quantum team were successful in transporting the qubits with a 99.999993% success rate and a connection rate of 2424/s, both numbers are world records and orders of magnitude better than previous solutions.
Professor Winfried Hensinger, Professor of Quantum Technologies at the University of Sussex and Chief Scientist and Co-founder at Universal Quantum said: “As quantum computers grow, we will eventually be constrained by the size of the microchip, which limits the number of quantum bits such a chip can accommodate. As such, we knew a modular approach was key to make quantum computers powerful enough to solve step-changing industry problems. In demonstrating that we can connect two quantum computing chips – a bit like a jigsaw puzzle – and, crucially, that it works so well, we unlock the potential to scale-up by connecting hundreds or even thousands of quantum computing microchips.”
While linking the modules at world-record speed, the scientists also verified that the ‘strange’ quantum nature of the qubit remains untouched during transport, for example, that the qubit can be both 0 and 1 at the same time.
Dr Sebastian Weidt, CEO and Co-founder of Universal Quantum, and Senior Lecturer in Quantum Technologies at the University of Sussex said: “Our relentless focus is on providing people with a tool that will enable them to revolutionise their field of work. The Universal Quantum and University of Sussex teams have done something truly incredible here that will help make our vision a reality. These exciting results show the remarkable potential of Universal Quantum’s quantum computers to become powerful enough to unlock the many lifechanging applications of quantum computing.”
Universal Quantum has just been awarded €67 million from the German Aerospace Center (DLR) to build two quantum computers where they will deploy this technology as part of the contract. The University of Sussex spin-out was also recently named as one of the 2022 Institute of Physics award winners in the Business Start-up category.
Weidt added: “The DLR contract was likely one of the largest government quantum computing contracts ever handed out to a single company. This is a huge validation of our technology. Universal Quantum is now working hard to deploy this technology in our upcoming commercial machines.”
Dr Mariam Akhtar led the research during her time as Research Fellow at the University of Sussex and Quantum Advisor at Universal Quantum. She said: “The team has demonstrated fast and coherent ion transfer using quantum matter links. This experiment validates the unique architecture that Universal Quantum has been developing – providing an exciting route towards truly large-scale quantum computing.”
Professor Sasha Roseneil, Vice-Chancellor of the University of Sussex, said: “It’s fantastic to see that the inspired work of the University of Sussex and Universal Quantum physicists has resulted in this phenomenal breakthrough, taking us a significant step closer to a quantum computer that will be of real societal use. These computers are set to have boundless applications – from improving the development of medicines, creating new materials, to maybe even unlocking solutions to the climate crisis. The University of Sussex is investing significantly in quantum computing to support our bold ambition to host the world’s most powerful quantum computers and create change that has the potential to positively impact so many people across the world. And with teams spanning the spectrum of quantum computing and technology research, the University of Sussex has both a breadth and a depth of expertise in this. We are still growing our research and teaching in this area, with plans for new teaching programmes, and new appointments.”
Professor Keith Jones, Interim Provost and Pro-Vice Chancellor for Research and Enterprise at the University of Sussex, said of the development: “This is a very exciting finding from our University of Sussex physicists and Universal Quantum. It proves the value and dynamism of this University of Sussex spin-out company, whose work is grounded in rigorous and world-leading academic research. Quantum computers will be pivotal in helping to solve some of the most pressing global issues. We're delighted that Sussex academics are delivering research that offers hope in realising the positive potential of next-generation quantum technology in crucial areas such as sustainability, drug development, and cybersecurity.”
For over 60 years the aim of our courses, research, culture and campus has been to stimulate, excite and challenge. So, from scientific discovery to global policy, from student welfare to career development, the University of Sussex innovates and takes a lead. And today, in every part of society and across the world, you will find someone from the University of Sussex making an original and valuable contribution. Visit www.sussex.ac.uk
ABOUT UNIVERSAL QUANTUM
Universal Quantum builds quantum computers that will one day help humanity solve some of its most pressing problems in areas such as drug discovery and climate change as well as shed light on its biggest scientific mysteries. To achieve this, quantum computers with millions of qubits are required, which is often described as one of the biggest technology challenges of our time.
Universal Quantum has developed a unique modular architecture to solve exactly that challenge. Its trapped ion-based electronic quantum computing modules are manufactured using available silicon technology. Individual modules are connected using its record-breaking UQ Connect technology to form an architecture that can scale to millions of qubits.
With 15+ years of quantum computing experience, Universal Quantum is a spin-out from the University of Sussex, founded by Dr Sebastian Weidt and Professor Winfried Hensinger in 2018 and supported by leading investors. Visit www.universalquantum.com
University of Sussex and Universal Quantum scientists, Professor Winfried Hensinger and Dr Sebastian Weidt in University of Sussex quantum computing labs.
Quantum computer setup at the University of Sussex with two quantum computer microchips where quantum bits are transferred from one microchip to another with record speed.
A high-fidelity quantum matter-link between ion-trap microchip modules
ARTICLE PUBLICATION DATE
8-Feb-2023
COI STATEMENT
The authors declare the following competing interests: M.A., F.B., F.R.L.-G., S.W. and W.K.H. are associated and/or hold shares with quantum computing company Universal Quantum Ltd. that will make use of some of the findings of this article in the quantum computers they develop. The remaining authors declare no other competing interests.
Tuesday, May 05, 2026
Qubit Pharmaceuticals announces strategic collaboration with Singapore’s Centre for Quantum Technologies to advance quantum algorithms for drug discovery
Credit: Image credit: Centre for Quantum Technologies, Singapore
Paris / Singapore — 30 April 2026 — Qubit Pharmaceuticals today announced a strategic research collaboration with the Centre for Quantum Technologies (CQT) in Singapore to develop and use novel quantum algorithms for molecular discovery.
The two-year collaboration combines Qubit Pharmaceuticals’ expertise in quantum chemistry and sampling techniques with CQT’s deep capabilities in quantum computing, circuit design, and experimental implementation. The goal is to bring advanced quantum chemistry methods closer to real-world drug discovery applications.
Together, the teams are designing and testing algorithms for quantum chemistry, including variational quantum eigensolvers, quantum phase estimation, and quantum Markov Chain Monte Carlo (qMCMC) sampling. These algorithms target key computational bottlenecks in drug discovery, such as improving the accuracy of quantum chemistry calculations for better drug property predictions and enabling more efficient sampling techniques for molecular simulations.
“Quantum algorithms for chemistry have been studied for decades, but real implementations remain rare,” said Robert Marino, CEO of Qubit Pharmaceuticals. “By working with CQT and leveraging access to state-of-the-art quantum hardware, we aim to transition these algorithms from theoretical constructs into real computational tools for molecular discovery.”
The researchers aim to explore whether quantum algorithms can approach the highest level of accuracy in molecular simulations while potentially delivering quadratic or even exponential computational advantages compared to classical approaches. They will validate their algorithms on quantum simulators before deploying to real quantum hardware.
The project is supported by Singapore’s National Quantum Computing Hub, through which CQT researchers have access to run experiments on Quantinuum’s quantum systems, including the H2 and Helios systems.
Marino and Baptiste Claudon presented first results from these experiments on 23 April at a Quantum Industry Day in Singapore organised by Quantinuum and Singapore’s National Quantum Office for some 250 invited participants.
The team has implemented the qMCMC algorithm, testing several different encodings. This is the first time this type of algorithm has been deployed to quantum hardware, and the team has published details to the physics preprint server arXiv (https://arxiv.org/abs/2603.08395).
The collaboration is led by Jean-Philip Piquemal at Qubit Pharmaceuticals and Sergi Ramos-Calderer at CQT, with an initial team of four researchers across both organisations. Additional researchers are expected to join as the programme expands.
"Through our collaboration with Quantinuum, we have the opportunity to test quantum algorithms on some of the best gate-based quantum machines available today,” said Ramos-Calderer. “Algorithm design must move hand-in-hand with hardware improvements, and this work is a meaningful step in this direction."
“Drug discovery is fundamentally a molecular simulation challenge. If we can model chemistry with greater fidelity and efficiency, we can make better decisions earlier in the pipeline,” said Piquemal, Chief Scientific Officer / Co-founder, Qubit Pharmaceuticals. “This collaboration allows us to rigorously test whether quantum algorithms can move from scientific promise to practical utility on problems that matter.”
“We are interested in more than benchmark circuits or abstract demonstrations,” said Claudon, Quantum Physics Engineer, Qubit Pharmaceuticals. “Our focus is implementing algorithms that can address real computational bottlenecks in chemistry. Working with CQT and Quantinuum hardware gives us an opportunity to evaluate these methods under realistic conditions and learn what is required to make them useful for molecular discovery.”
Over the longer term, the team aims to generate real molecular simulation data produced directly by quantum algorithms and integrate these capabilities into future drug discovery workflows.
Qubit Pharmaceuticals was founded in 2020 with the vision of co-developing, in partnership with pharmaceutical and biotech companies, safer and more effective new drugs. The company emerged from the academic research of five internationally renowned scientists: Louis Lagardère (Sorbonne University and CNRS), Matthieu Montes (CNAM), Jean-Philip Piquemal (Sorbonne University and CNRS), Jay Ponder (Washington University in St. Louis), and Pengyu Ren (University of Texas at Austin). Qubit Pharmaceuticals leverages its Atlas platform to discover new drugs through molecular simulation and modeling, accelerated by hybrid HPC and quantum computing.
Qubit Pharmaceuticals was named a "2024 Technology Pioneer" by the World Economic Forum and has forged high-level partnerships, including with Institut Curie, Sorbonne University, and the Institute of Pharmacology at the University of Sherbrooke (Canada).
For further information, including the drug discovery portfolio, visit www.qubit-pharmaceuticals.com
About the Centre for Quantum Technologies, Singapore
The Centre for Quantum Technologies (CQT) is Singapore’s flagship national research centre in quantum technologies. Supported under Singapore’s National Quantum Strategy, the centre has nodes at partner institutions and coordinates research talent across the country. CQT’s partner institutions are universities – the National University of Singapore, Nanyang Technological University, Singapore, and the Singapore University of Technology and Design – and the Agency for Science, Technology and Research.
CQT brings together physicists, computer scientists and engineers to do basic research on quantum physics and to build devices based on quantum phenomena. Experts in this new discipline of quantum technologies are applying their discoveries in computing, communications, and sensing.
The National University of Singapore (NUS) is Singapore’s flagship university, which offers a global approach to education, research and entrepreneurship, with a focus on Asian perspectives and expertise. We have 15 colleges, faculties and schools across three campuses in Singapore, with more than 40,000 students from 100 countries enriching our vibrant and diverse campus community. We have also established more than 20 NUS Overseas Colleges entrepreneurial hubs around the world.
Our multidisciplinary and real-world approach to education, research and entrepreneurship enables us to work closely with industry, governments and academia to address crucial and complex issues relevant to Asia and the world. Researchers in our faculties, research centres of excellence, corporate labs and more than 30 university-level research institutes focus on themes that include energy; environmental and urban sustainability; treatment and prevention of diseases; active ageing; advanced materials; risk management and resilience of financial systems; Asian studies; and Smart Nation capabilities such as artificial intelligence, data science, operations research and cybersecurity.
For more information on NUS, please visit nus.edu.sg.
About Quantinuum
Quantinuum is a leading quantum computing company offering a full-stack platform designed to make quantum computing deployable in real-world environments. The company has commercially deployed multiple generations of quantum systems built on the well-established QCCD architecture, which it has implemented with novel designs and capabilities to achieve the industry’s highest accuracy levels based on average two-qubit gate fidelity.* Quantinuum has active engagements with market leaders across pharmaceuticals, material science, financial services, and government and industrial markets. The company has a global workforce of approximately 700 employees, including top scientists and researchers. Over 70% of its technology team hold PhDs. Quantinuum’s headquarters is in Broomfield, Colorado, with additional facilities across the United States, United Kingdom, Germany, Japan, and Singapore.
Researchers at the Niels Bohr Institute have broken a long standing barrier by managing to send single photons - that can’t be copied or split and thus are secure - in the network of optical fibers we already have. This opens up a broad range of applications relying on secure Quantum information.
Signal loss in optical fibers
Quantum dots are unsurpassed in their ability to generate coherent single photons - single particles of light, which cannot be split or copied and therefore are secure for quantum communication. So far, the problem was that the best quantum dots only worked around 930 nm wavelengths, which is far short of the telecommunication compatible wavelengths starting at 1260 nm. Only these longer wavelengths can be used to distribute the information-carrying photons far and has so far been restricted to sub-optimal platforms.
Now, scientists have managed to create a new type of quantum dot, which exploits the best of both worlds.
Noise is the enemy of everything quantum
Researchers working with quantum light sources have long attempted to work directly in the telecom band, but the photons produced at these wavelengths were always very noisy, as Leonardo Midolo explains. “Noisy in this context means that you couldn’t generate one photon after another with the same properties. The photons need to be perfectly identical, and achieving this level of quantum coherence in the telecom band has proven extremely challenging”.
Two major challenges overcome
Leonardo Midolo and his team have succeeded in overcoming two major challenges in one go: their photons are now coherent and identical, and they are emitted directly in the original telecom band (around 1300 nm), the same wavelength used in today’s standard fiber-optic networks. This opens the door to linking photonic quantum technologies to the existing communication infrastructure.
For years, a kind of “accepted truth” circulated within the research community: yes, you can make photons in the telecom band, but they will be noisy and incoherent – which, as Leonardo notes, essentially meant “useless” for quantum applications. Their breakthrough challenges that assumption head-on.
This progress relies strongly on collaboration with the research group in Bochum, Germany, who optimized the growth of these ultra-low-noise quantum dot emitters.
“At the Niels Bohr Institute, we then use advanced nanofabrication in our cleanroom to pattern these materials into quantum photonic circuits,” adds Marcus Albrechtsen, joint first author of the study. “We fabricate nanochips and probe them with lasers at low temperatures to confirm they emit highly coherent single photons.”
Extras for free
Just as important – a kind of icing on the cake - is the fact that photonic integrated circuits, chip-scale optical circuits that miniaturize complex optical setups, are commonly made in silicon. It is the most common, cost-effective material for controlling and routing light on a chip. However, silicon absorbs much of the light in wavelengths below 1100 nanometers, which has so-far precluded the integration of near-infrared emitters like quantum dots in these photonic chips. This means that if you can make your photons coherent, identical, and operate at 1300 nm you can directly embed quantum-grade light sources with commercial silicon photonic chips.
What happens now?
This achievement effectively removes one of the biggest roadblocks to build real, large‑scale quantum networks. It means quantum chips, quantum repeaters, and long‑distance quantum communication can now be built on top of the world’s existing fiber infrastructure. No complicated workarounds like nonlinear frequency conversion. Just plug‑and‑play quantum technology. In short: the door to a functional quantum internet is now officially open. And with this platform in hand, the race is on to build the first scalable quantum network.
Factbox: Quantum dots
A quantum dot is a collection of atoms, roughly 30,000 in these devices, that are different from their surroundings – so they behave like an artificial atom itself.
The individual dot is about 5,2 nm tall and 20 nm wide. They work as emitters for single photons in this way: The material boundaries of the Quantum dot locally form discrete energy levels like a real atom - discrete as in quantized and therefore "quantum" in nature.
This means that when a laser pulse/beam with many photons hits the quantum dot it gets excited, an electron is locally trapped in the dot and after a short time it decays and emits a single photon. Not two or a decimal amount but exactly one photon.
This single photon can be used for quantum computation or secure communication since information stored in a single photon cannot be copied.
Quantum technology has promising potential to revolutionize how large and complex amounts of information are processed. While already in use primarily in laboratory and research settings globally, quantum technologies are in a transition phase for broader industry applications across many economic sectors.
In researching fundamental aspects of quantum physics, or the behavior of nature at the smallest scales — involving atoms, electrons and photons — a study led by Cal Poly Physics Department Lecturer Ian Powell analyzed how a changing magnetic field can make matter behave in unusual ways.
Powell and student researcher Louis Buchalter, who graduated with a Cal Poly bachelor's degree in physics in 2025, published the article “Flux-Switching Floquet Engineering” in the journal Physical Review B, highlighting how changing magnetic fields over time in time can create quantum states that do not exist in any stationary material (remaining in the same state as time elapses).
“On a big-picture level, I would describe this as an advance in our understanding of how time-dependent control can create and organize new forms of quantum matter,” Powell said. “The central idea is that useful quantum properties can depend not just on what a material is, but on how it is driven in time. In our case, we show that periodically changing a magnetic field can produce driven quantum phases with no static counterpart.”
By engineering new quantum behaviors by timing the field, physicists can potentially create technologies that are very stable and hard to disrupt by “noise” or imperfections that can interfere with quantum technology functionality and avoid system errors.
Admittedly, Powell said that it’s difficult to describe the technical aspects of the study to non-physicists. But conceptually, research points to possible routes for engineering these kinds of exotic driven quantum states in controlled platforms such as ultracold-atom experiments.
“The most direct industry relevance of our study is to quantum computing and quantum simulation, rather than to a specific end-use sector at this stage,” Powell said. “Any eventual impact on areas like pharmaceuticals, finance, manufacturing or aerospace would likely be indirect, by contributing to the longer-term development of better quantum technologies. To move toward industry use, the next steps would be experimental validation and further work connecting these ideas to realistic quantum-device platforms.”
Applying principles of physics, the work also revealed a mathematical organizing rule that echoes patterns more commonly associated with higher-dimensional quantum systems, suggesting that relatively simple driven systems may offer a new way to study that kind of physics.
The research shows that the exotic driven phases can appear, but also uncovers a precise organizing rule for the topological phase diagram of the system, or a visual map that delineates distinct, stable quantum phases of matter based on unchanging topological numbers.
The use of physics principles in quantum mechanics leverages the ability of a computational system to process information more quickly, run massive simulations, and comprehensively analyze far more data than classical computing.
Magnetic fields are one of the main tools used to control and read out quantum bits (or qubits), the fundamental unit of information used in quantum technology. Qubits are comparable to the units of 0s and 1s in classicalcomputing (applied in commonplace computing currently) used to represent physical electrical states.
As a student researcher working alongside Powell, Buchalter said that co-authoring the article taught him “a lot about the process of conducting research and how new research findings are effectively communicated with the broader scientific community.”
“I learned that research is rarely a straightforward process, often requiring persistence and creative problem solving during the course of a research project,” Buchalter said. “I believe our results help demonstrate the power of Floquet engineering for realizing quantum systems with highly-tunable properties, paving the way for further research into periodically driven quantum matter and the development of its applications.”
Buchalter plans to pursue a Master of Science degree in materials science and engineering at the University of Washington in the fall, and to conduct experimental research on quantum matter. He’s considering pursuing a career at a national lab on the development of quantum devices after finishing his education.
“I initially took on the project due to my interest in condensed matter physics, however, I became fascinated with the field of quantum materials through my experience,” Buchalter said. “I am very interested in continuing to study quantum matter and helping develop its applications in electronic and photonic devices.”
Lead author and PhD student Vassili Matsos looking at the Paul trap quantum computing device in the Quantum Control Laboratory at the University of Sydney.
To build a large-scale quantum computer that works, scientists and engineers need to overcome the spontaneous errors that quantum bits, or qubits, create as they operate.
Scientists encode these building blocks of quantum information to suppress errors in other qubits so that a minority can operate in a way that produces useful outcomes.
As the number of useful (or logical) qubits grows, the number of physical qubits required grows even further. As this scales up, the sheer number of qubits needed to create a useful quantum machine becomes an engineering nightmare.
Now, for the first time, quantum scientists at the Quantum Control Laboratory at the University of Sydney Nano Institute have demonstrated a type of quantum logic gate that drastically reduces the number physical qubits needed for its operation.
To do this, they built an entangling logic gate on a single atom using an error-correcting code nicknamed the ‘Rosetta stone’ of quantum computing. It earns that name because it translates smooth, continuous quantum oscillations into clean, digital-like discrete states, making errors easier to spot and fix, and importantly, allowing a highly compact way to encode logical qubits.
GKP CODES: A ROSETTA STONE FOR QUANTUM COMPUTING
This curiously named Gottesman-Kitaev-Preskill (GKP) code has for many years offered a theoretical possibility for significantly reducing the physical number of qubits needed to produce a functioning ‘logical qubit’. Albeit by trading efficiency for complexity, making the codes very difficult to control.
Research published today in Nature Physics demonstrates this as a physical reality, tapping into the natural oscillations of a trapped ion (a charged atom of ytterbium) to store GKP codes and, for the first time, realising quantum entangling gates between them.
Led by Sydney Horizon Fellow Dr Tingrei Tan at the University of Sydney Nano Institute, scientists have used their exquisite control over the harmonic motion of a trapped ion to bridge the coding complexity of GKP qubits, allowing a demonstration of their entanglement.
“Our experiments have shown the first realisation of a universal logical gate set for GKP qubits,” Dr Tan said. “We did this by precisely controlling the natural vibrations, or harmonic oscillations, of a trapped ion in such a way that we can manipulate individual GKP qubits or entangle them as a pair.”
QUANTUM LOGIC GATE
A logic gate is an information switch that allows computers – quantum and classical – to be programmable to perform logical operations. Quantum logic gates use the entanglement of qubits to produce a completely different sort of operational system to that used in classical computing, underpinning the great promise of quantum computers.
First author Vassili Matsos is a PhD student in the School of Physics and Sydney Nano. He said: “Effectively, we store two error-correctable logical qubits in a single trapped ion and demonstrate entanglement between them.
“We did this using quantum control software developed by Q-CTRL, a spin-off start-up company from the Quantum Control Laboratory, with a physics-based model to design quantum gates that minimise the distortion of GKP logical qubits, so they maintain the delicate structure of the GKP code while processing quantum information.”
A MILESTONE IN QUANTUM TECHNOLOGY
What Mr Matsos did is entangle two ‘quantum vibrations’ of a single atom. The trapped atom vibrates in three dimensions. Movement in each dimension is described by quantum mechanics and each is considered a ‘quantum state’. By entangling two of these quantum states realised as qubits, Mr Matsos created a logic gate using just a single atom, a milestone in quantum technology.
This result massively reduces the quantum hardware required to create these logic gates, which allow quantum machines to be programmed.
Dr Tan said: “GKP error correction codes have long promised a reduction in hardware demands to address the resource overhead challenge for scaling quantum computers. Our experiments achieved a key milestone, demonstrating that these high-quality quantum controls provide a key tool to manipulate more than just one logical qubit.
“By demonstrating universal quantum gates using these qubits, we have a foundation to work towards large-scale quantum-information processing in a highly hardware-efficient fashion.”
Across three experiments described in the paper, Dr Tan’s team used a single ytterbium ion contained in what is known as a Paul trap. This uses a complex array of lasers at room temperature to hold the single atom in the trap, allowing its natural vibrations to be controlled and utilised to produce the complex GKP codes.
This research represents an important demonstration that quantum logic gates can be developed with a reduced physical number of qubits, increasing their efficiency.
Download photos of the researchers and artist’s impression at this link.
Outside of work hours, please call +61 2 8627 0246 (directs to a mobile number) or email media.office@sydney.edu.au.
Research
Matsos, V. et al ‘Universal quantum gate set for Gottesman-Kitaev-Preskill logical qubits’ (Nature Physics 2025) DOI: 10.1038/s41567-025-03002-8
Declaration
The authors declare no competing interests. Funding was received from the Australian Research Council, Sydney Horizon Fellowship, the US Office of Naval Research, the US Army Research Office, the US Air Force Office of Scientific Research, Lockheed Martin, Sydney Quantum Academy and private funding from H. and A. Harley.
Artist's impression of the entangled logic gate built by University of Sydney quantum scientists.
Dr Tingrei Tan (left) and his PhD student Vassili Matsos inspect the Paul trap used in this experiment in the Quantum Control Laboratory at the University of Sydney Nano Institute.
Physicists have developed a breakthrough concept in quantum encryption that makes private communication more secure over significantly longer distances, surpassing state-of-the-art technologies. For decades, experts believed such a technology upgrade required perfect optical hardware, namely, light sources that strictly emit one light particle (photon) at a time—something extremely difficult and expensive to build. But the new approach uses innovative encryption protocols applied to tiny, engineered materials called quantum dots to send encrypted information securely, even with imperfect light sources. Real-world tests show it can outperform even the best of current systems, potentially bringing quantum-safe communication closer to everyday use.
A team of physicists has made a breakthrough that could bring secure quantum communication closer to everyday use — without needing flawless hardware.
The research, led by PhD students Yuval Bloom and Yoad Ordan, under the guidance of Professor Ronen Rapaport from theRacah Institute of Physics at Hebrew University in collaboration with researchers from Los-Alamos National Labs, and published in PRX Quantum, introduces a new practical approach that significantly improve how we send quantum encrypted information using light particles — even when using imperfect equipment.
Cracking a 40-Year-Old Challenge in Quantum Communication
For four decades, the holy grail of quantum key distribution (QKD) — the science of creating unbreakable encryption using quantum mechanics — has hinged on one elusive requirement: perfectly engineered single-photon sources. These are tiny light sources that can emit one particle of light (photon) at a time. But in practice, building such devices with absolute precision has proven extremely difficult and expensive.
To work around that, the field has relied heavily on lasers, which are easier to produce but not ideal. These lasers send faint pulses of light that contain a small, but unpredictable, number of photons — a compromise that limits both security and the distance over which data can be safely transmitted, as a smart eavesdropper can “steal” the information bits that are encoded simultaneously on more than one photon.
A Better Way with Imperfect Tools
Bloom, Ordan, and their team flipped the script. Instead of waiting for perfect photon sources, they developed two new protocols that work with what we have now — sub-Poissonian photon sources based on quantum dots, which are tiny semiconductor particles that behave like artificial atoms.
By dynamically engineering the optical behavior of these quantum dots and pairing them with nanoantennas, the team was able to tweak how the photons are emitted. This fine-tuning allowed them to suggest and demonstrate two advanced encryption strategies:
A truncated decoy state protocol: A new version of a widely used quantum encryption approach, tailored for imperfect single photon sources, that weeds out potential hacking attempts due to multi-photon events.
A heralded purification protocol: A new method that dramatically improves signal security by "filtering" the excess photons in real time, ensuring that only true single photon bits are recorded.
In simulations and lab experiments, these techniques outperformed even the best versions of traditional laser-based QKD methods — extending the distance over which a secure key can be exchanged by more than 3 decibels, a substantial leap in the field.
A Real-World Test and a Step Toward Practical Quantum Networks
To prove it wasn’t just theory, the team built a real-world quantum communication setup using a room-temperature quantum dot source. They ran their new reinforced version of the well-known BB84 encryption protocol — the backbone of many quantum key distribution systems — and showed that their approach was not only feasible but superior to existing technologies.
What’s more, their approach is compatible with a wide range of quantum light sources, potentially lowering the cost and technical barriers to deploying quantum-secure communication on a large scale.
“This is a significant step toward practical, accessible quantum encryption,” said Professor Rapaport. “It shows that we don’t need perfect hardware to get exceptional performance — we just need to be smarter about how we use what we have.”
Co-Lead author Yuval Bloom added, “We hope this work helps open the door to real-world quantum networks that are both secure and affordable. The cool thing is that we don’t have to wait, it can be implemented with what we already have in many labs world-wide”
