SCI-FI-TEK-77 YEARS IN THE MAKING

IBM quantum computer sees performance gains with QEC ‘primitives’


By Dr. Tim Sandle

June 2, 2025

DIGITAL JOURNAL

Leaping forward with quantum technology. — Image by © Tim Sandle.

In a recently published peer-reviewed paper researchers applying quantum error correction (QEC) ‘primitives’ on an IBM superconducting processor generated a record 75-qubit GHZ entangled state and higher fidelity gates with less resources required compared to current appoaches.

Quantum error correction (QEC) is a foundational technique that protects fragile quantum information from errors caused by noise and hardware imperfections, making it essential for scalable, reliable quantum computing. Progress in experimental QEC demonstrations has been rapid; however, fully error-corrected calculations remain difficult to implement on today’s hardware, often delivering limited performance gains at high resource costs.

In relation to this, generating large-scale quantum entanglement – a key resource for quantum computing and communication – has remained a significant challenge due to noise and device constraints. Entanglement is part of the ‘secret sauce’ of quantum computers, but it is also one of their most difficult properties to create and maintain. In the future, many quantum algorithms will rely on entanglement to perform computation.

Global effort to build more robust and powerful quantum computers

Previous demonstrations of large-scale entangled state preparation often relied on logical encoding, leading to a high overhead in both qubit count and shot count due to a large discard rate. In this work, Q-CTRL has overcome both hurdles through a strategic application of QEC primitives without logical encoding, yielding significant advantages on superconducting processors while only requiring a modest overhead.

The findings suggest that QEC primitives, even without full logical encoding, could allow users to experience quantum computational advantage over supercomputers earlier than expected. QEC primitives are the fundamental components of quantum error correction protocols.

The company Q-CTRL has announced two record-setting demonstrations that redefine what can be achieved with long-range entanglement generation.

Two demonstrations

With the demonstrations, the first sets a new state-of-the-art in the implementation of a long-range CNOT gate using a novel teleportation protocol based on unitary preparation of a GHZ state, followed by a unitary disentangling step. This approach has the advantage that the final state of the disentangled qubits reveals errors that have occurred during the application of the gate.

With the second, Q-CTRL generated large GHZ states using a protocol that allows for the integration of sparse error detection through ancillary stabiliser measurements. In quantum computing, a Greenberger–Horne–Zeilinger (GHZ) state is a special type of entangled state involving three or more qubits that are perfectly correlated across all qubits.

Most other methods discard almost all shots at large scales, whereas Q-CTRL observes a comparatively low discard rate, where over 80% of the shots are kept in the case of generating a 27-qubit GHZ state and over 21% in the 75-qubit state. These results demonstrate that incorporating QEC primitives on the physical level can deliver a substantial net improvement in the capability of a near-term quantum computer relative to the best alternative.

QEC primitives = significant computational advantages

“This work demonstrates that QEC primitives, even without full logical encoding, can offer significant computational advantages with only modest resource overhead,” says Yuval Baum, Head of Quantum Computing Research in a message sent to Digital Journal. “By designing smart protocols, leveraging intrinsic symmetries and combining strategic error detection, we achieve high-fidelity long-range CNOT gates and generate a 75-qubit GHZ state with genuine multipartite entanglement—the largest reported to date. These results suggest that meaningful benefits from QEC are already accessible on current-generation hardware.”

These record-setting results underscore Q-CTRL’s commitment to fundamental research that makes quantum technology useful today. With limited qubit and runtime resources in the near term, it is helpful to consider the adoption of low-overhead quantum error correction (QEC) subroutines on the physical level without the need for QEC encoding.

By combining error suppression and error detection, this novel paradigm is a step toward useful quantum computing and represents a new building block to the growing quantum error-reduction toolkit.

These achievements contribute directly to the global effort to build more robust and powerful quantum computers, accelerating the timeline for achieving quantum advantage.

Wendelstein 7-X sets new performance records in nuclear fusion research

World's most powerful stellarator sets record in a key parameter of fusion physics: the triple product

Max-Planck-Institut für Plasmaphysik (IPP)

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View into the Wendelstein 7-X experimental hall at the Max Planck Institute for Plasma Physics in Greifswald, Germany

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Credit: MPI for Plasma Physics, Jan Hosan

On the path toward a fusion power plant, stellarators are among the most promising concepts. In the future, they could generate usable energy by fusing light atomic nuclei. This reaction must take place in a plasma — a hot gas of ionized particles heated to many tens of millions of degrees Celsius. Stellarators use magnetic confinement to hold the plasma: the plasma is trapped by a complex and powerful magnetic field, floating inside a donut-shaped vacuum chamber. With Wendelstein 7-X (W7-X), the Max Planck Institute for Plasma Physics (IPP) in Greifswald, with support from the European fusion consortium EUROfusion, is operating the world's largest and most powerful experiment of its kind. W7-X is designed to demonstrate that stellarators can, in practice, achieve the outstanding properties predicted by theory – and thus qualify as a concept for future fusion power plants.

World-best triple product for long plasma durations

In the OP 2.3 campaign, which ended on May 22, the international W7-X team achieved a new world record for the triple product in long plasma discharges: on this last day, they sustained a new peak value of this key fusion parameter (see explanation below) for 43 seconds. Wendelstein 7-X thus surpassed the best performances of fusion devices of the tokamak type for longer plasma durations.

Tokamaks also rely on magnetic confinement but are much better studied due to their simpler design. The highest values for the triple product were achieved by the Japanese Tokamak JT60U (decommissioned in 2008) and the European Tokamak facility JET in Great Britain (decommissioned in 2023). With short plasma durations of just a few seconds, they remain the clear front-runners.  In terms of longer plasma durations, which are important for a future power plant, Wendelstein 7-X is now ahead, even though JET had three times the plasma volume. Size makes it much easier to achieve high temperatures in fusion reactors.

"The new record is a tremendous achievement by the international team. It impressively demonstrates the potential of Wendelstein 7-X. Elevating the triple product to tokamak levels during long plasma pulses marks another important milestone on the way toward a power-plant-capable stellarator," says Prof. Dr. Thomas Klinger, Head of Operations at Wendelstein 7-X and Head of Stellarator Dynamics and Transport at IPP.

Key to success: the new pellet injector from Oak Ridge National Laboratory

The new triple product world record for long pulses was made possible by the close collaboration between the European Wendelstein 7-X team in Greifswald and partners from the USA. A key role was played by the new pellet injector (more details at the end of this article), which injects frozen hydrogen pellets into the plasma, enabling long plasma durations through continuous refueling. The U.S. Department of Energy’s (DOE) Oak Ridge National Laboratory (ORNL) in Tennessee developed this highly sophisticated and globally unique injector and successfully put it into operation at Wendelstein 7-X.

During the record-setting experiment, about 90 frozen hydrogen pellets, each about a millimeter in size, were injected over 43 seconds, while powerful microwaves simultaneously heated the plasma. Precise coordination between heating and pellet injection was crucial to achieve the optimal balance between heating power and fuel supply. The key was operating the pellet injector with variable pre-programmed pulse rates for the first time — a scheme executed with impressive precision. This method is directly relevant for future fusion reactors and can potentially extend plasma durations to several minutes.

The use of pellets was made possible thanks to preliminary work carried out by several European laboratories, including simulation calculations by the Centre for Energy, Environmental and Technological Research (CIEMAT) in Spain and observations using ultra-fast cameras by the HUN-REN Centre for Energy Research in Budapest. The microwave heating system (more precisely: electron cyclotron resonance) was developed in collaboration with the Karlsruhe Institute of Technology (KIT) and a team from the University of Stuttgart. It is considered the most promising method for bringing plasma to temperatures relevant for fusion.

In the record-breaking experiment, the plasma temperature was raised to over 20 million degrees Celsius, reaching a peak of 30 million degrees. Measurements to calculate the triple product were provided, among others, by Princeton Plasma Physics Laboratory, which operates an X-ray spectrometer for ion temperature diagnostics at W7-X. The necessary electron density data came from IPP's worldwide unique interferometer. The energy confinement time required for the triple product calculation was also determined using diagnostic tools developed at IPP.

Additional highlights from the OP 2.3 campaign

During the OP 2.3 experimental campaign, Wendelstein 7-X achieved two further milestones:

1. Energy turnover was increased to 1.8 gigajoules (plasma duration: 360 seconds).
   The previous record from February 2023 was 1.3 gigajoules. Energy turnover is calculated as the product of injected heating power and plasma duration.
   Maintaining continuous high-energy input and removing the generated heat are prerequisites for future power plant operation. The corresponding best value for the 1000-second discharge in the Tokamak EAST (China) was even slightly exceeded by Wendelstein 7-X.
2. Plasma pressure relative to magnetic pressure reached 3% for the first time across the full plasma volume. In a dedicated experiment series, the magnetic field was deliberately reduced to about 70%, lowering magnetic pressure and allowing plasma pressure to rise. This ratio is a key parameter for extrapolating to a fusion power plant, where 4–5% across the volume will be needed. The new record value was accompanied by a peak ion temperature of around 40 million degrees Celsius.

Prof. Dr. Robert Wolf, Head of Stellarator Heating and Optimization at IPP, summarizes:
"The records of this experimental campaign are much more than mere numbers. They represent a significant step forward in validating the stellarator concept — made possible through outstanding international collaboration."

View inside the vacuum vessel of the stellarator Wendelstein 7-X iat the Max Planck Institute for Plasma Physics in Greifswald, Germany

Credit

MPI for Plasma Physics, Jan Hosan

More information about the triple product

The triple product — also known as the Lawson criterion — is the key metric for success on the path to a fusion power plant. Only when a certain threshold is exceeded can a plasma produce more fusion power than the heating power invested. This marks the point where the energy balance becomes positive, and the fusion reaction can sustain itself without continued external heating.

For a fusion power plant, the required threshold is:

n∙T∙𝜏 = 3 × 10²¹ m⁻³ keV s

The triple product is derived from three factors:

• the particle density of the plasma n,
• its temperature T (more precisely: the temperature of the ions between which fusion reactions take place) and
• the energy confinement time 𝜏 (pronounced: tau), i.e. the time it takes for the thermal energy to escape from the plasma if no additional heat is supplied. The confinement time is therefore a measure of the thermal insulation.

In a future fusion power plant, a plasma with a high triple product (y-axis, logarithmic scale) must be maintained for long periods (x-axis). Previous fusion experiments only achieved high values for plasma durations of a very few seconds. On May 22, 2025, Wendelstein 7-X achieved the world record for plasma times of more than 30 seconds with a high fusion product. In this OP2.3 experiment campaign, further best values were achievedfor plasma durations between 30 and 40 seconds. Tokamaks remain the record holders for short plasma times.

Credit

MPI for Plasma Physics, Dinklage et al (to be published) / X. Litaudon et al 2024 Nucl. Fusion 64 015001

More information about the pellet injector

Since September 2024, the new continuously operating pellet injector has been successfully in use.
It was developed at Oak Ridge National Laboratory, a research center of the U.S. Department of Energy, specifically for Wendelstein 7-X, and it sets a global benchmark in its category.
The pellet injector ensures a steady supply of hydrogen particles into the plasma — a crucial requirement for future fusion power plants.

The device continuously forms a 3-millimeter-diameter strand of frozen hydrogen, from which 3.2-millimeter-long cylindrical pellets are cut at intervals of fractions of a second and fired into the plasma at speeds of 300 to 800 meters per second.

The pellet injector in the Wendelstein 7-X experimental hall at the Max Planck Institute for Plasma Physics in Greifswald, Germany.

Credit

MPI for Plasma Physics, Beate Kemnitz

German Federal Ministry of Research grants millions for “fusion talent” — Dr. Jonas Ohland will lead GSI/FAIR young investigators group

GSI Helmholtzzentrum für Schwerionenforschung GmbH

View inside the PHELIX laser system at GSI/FAIR

Credit

Photo: J. Hosan, GSI/FAIR

Starting June 1, 2025, Dr. Jonas Ohland, laser physicist at GSI/FAIR, will lead the young investigator group ALADIN (Adaptive Laser Architecture Development and INtegration). For this purpose, he will receive funding of 2.8 million euros over five years from the German Federal Ministry of Research, Technology and Space as part of the “Fusionstalente” (fusion talents) program. The ALADIN project lays the foundation for the realization of stable, efficient lasers for inertial confinement fusion.

Inertial fusion involves compressing and heating a tiny fuel capsule using extremely rapid energy input until nuclear fusion starts. Powerful laser beams could be used to achieve this uniform compression and ignition. However, these lasers must deliver high-energy pulses in quick succession, which exposes them to intense heat and stress. To make them viable for future power plants, smart and scalable solutions for beam control are needed — solutions that can be automated and integrated into large-scale systems.

The ALADIN young investigators group aims to fundamentally improve the control of such high-power lasers. Their approach: an “Adaptive Laser Architecture” (ALA) that integrates all key control elements directly into an intelligent support system. This setup allows for better beam guidance while reducing the need for manual intervention. ALA could enable the simultaneous control of hundreds of laser systems — a critical requirement for building large-scale fusion facilities.

“I am very grateful for this support and the opportunity to push the boundaries of laser beam control,” says Ohland. “With ALADIN, we aim to make significant progress in making next-generation high-power lasers more robust and practical — especially with regard to inertial fusion. Our goal is to bridge the gap between research and real-world applications in this rapidly evolving field.”

“The results will benefit not only fusion research, but also other areas where high-power lasers are needed — such as the laser industry or large-scale scientific facilities,” adds Professor Vincent Bagnoud, head of the GSI/FAIR research department “Plasma Physics/PHELIX”, to which Ohland belongs. “There is also great potential for our own high-power laser system PHELIX — a petawatt laser which can be combined with the ion beam from the particle accelerator for the experiments — to improve our operations and thus our research opportunities.”

Professor Thomas Nilsson, Scientific Managing Director of GSI and FAIR, says: “My congratulations on the young investigators group go to our ‘fusion talent’ Dr. Jonas Ohland. The successful funding application represents the wealth of ideas and the expertise of our young scientists. Training and supporting the next generation of researchers is a matter close to our hearts and a necessity for our future at the international accelerator facility FAIR. Fusion-related research will also play an important role in the FAIR research program.”

ALADIN is cooperating with Focused Energy GmbH, a fusion energy startup in Darmstadt, and other scientific institutions to develop and disseminate ALA technology in order to ensure its long-term industrial application. After the funding period, an ALADIN Community Competence Group hosted by GSI/FAIR will focus on open ALA research, industrial cooperation and education, financed by third-party funds and income from licenses and services.

About Dr. Jonas Ohland

Dr. Jonas Ohland studied at the Technical University of Darmstadt and obtained his PhD in 2022 with a thesis at the GSI/FAIR high-power laser PHELIX (Petawatt-High-Energy Laser for Ion Experiments). Subsequently he worked as a postdoc at the Apollon laser facility in Paris, France, as part of the THRILL project — a European research consortium coordinated by GSI to provide new designs and high-performance components for high-energy lasers with high repetition rates — before returning to GSI/FAIR in 2024. His pioneering work at Apollon led to impressive results in the field of real-time adaptive optics for high-power lasers and served as the basis for the ALADIN application.

About the “Fusionstalente” program

“Fusionstalente” — a young investigators program, initiated by the German Federal Ministry of Research, Technology and Space — aims to strengthen expertise in fusion research by fostering the development of young scientific talent. It supports early-career researchers through targeted funding of their own group, training opportunities, and access to cutting-edge fusion research facilities. By investing in the next generation of fusion scientists, the program contributes to advancing sustainable and innovative energy solutions in Germany and Europe. The Fusionstalente program is part of the funding program “Fusion 2040 – Research on the Way to the Fusion Power Plant”.