NASA’s Orion spacecraft is built around a single, uncompromising principle—crew must return home safely. From the millisecond‑response launch abort system (LAS) perched atop the capsule to the autonomous flight software that […]
Team effort Based at the University of Innsbruck, Ben Lanyon’s group has created a novel qubit register by trapping ten ions. (Courtesy: Victor Krutyanskiy/University of Innsbruck)
Researchers in Austria have entangled matter-based qubits with photonic qubits in a ten-ion system. The technique is scalable to larger ion-qubit registers, paving the way for the creation of larger and more complex quantum networks.
Ions in motion Each ion (large object) is moved one at a time into the “sweet spot” of the optical cavity. Once there, a laser beam drives the emission of a single photon (small object), entangled with the ion. The colours indicate ion–photon entanglement. (Courtesy: Universität Innsbruck/Harald Ritsch)
Quantum networks consist of matter-based nodes that store and process quantum information and are linked through photons (quanta of light). Already, Ben Lanyon’s group at the University of Innsbruck has made advances in this direction by entangling two ions in different systems. Now, in a new paper published in Physical Review Letters , they describe how they have developed and demonstrated a new method to entangle a string of ten ions with photons. In the future, this approach could enable the entanglement of sets of ions in different locations through light, rather than one ion at a time.
To achieve this, Lanyon and colleagues trapped a chain of 10 calcium ions in a linear trap in an optical cavity. By changing the trapping voltages in the trap, each ion was moved, one-by-one, into the cavity. Once inside, the ion was placed in the “sweet spot”, where the ion’s interaction with the cavity is the strongest. There, the ion emitted a single photon when exposed to a 393 nm Raman laser beam. This beam was tightly focused on one ion, guaranteeing that the emitted photon – collected in a single-mode optical fibre – comes out from one ion at a time. This process was carried out ten times, one per ion, to obtain a train of ten photons.
By using quantum state tomography, the researchers reconstructed the density matrix, which describes the correlation between the states of ions (i) and photons (j). To do so, they measure every ion and photon state in three different basis, resulting in nine Pauli-basis configurations of quantum measurements. From the density matrix, the concurrence (a measure of entanglement) between the ion (i) and photon (j) was found to be positive only when i = j, and equal to zero otherwise. This implies that the ion is uniquely entangled with the photon it produced, and unentangled with the photon produced by other ions.
From the density matrix, they also calculate the fidelity with the Bell state (a state of maximum entanglement), yielding an average 92%. As Marco Canteri points out, “this fidelity characterizes the quality of entanglement between the ion-photon pair for i=j”.
This work developed and demonstrated a technique whereby matter-based qubits and photonic qubits can be entangled, one at a time, in ion strings. Now, the group aims to “demonstrate universal quantum logic within the photon-interfaced 10-ion register and, building up towards entangling two remote 10-ion processors through the exchange of photons between them,” explains team member Victor Krutyanskiy. If this method effectively scales to larger systems, more complex quantum networks could be built. This would lead to applications in quantum communication and quantum sensing.
STRASBOURG, November 17th, 2025 – Leanspace, a European satellite operations technology provider, today announced it has raised €10 million in Series A funding. The financing round includes new strategic investors: […]
For nearly 80 years, the specter of nuclear war has haunted humankind, shaping foreign policy, military strategy, and international relations. The principle of “mutually assured destruction” (MAD) has been the cornerstone of global stability since the dawn of the atomic age. Yet, this fragile equilibrium has always depended on one terrifying certainty: No defense is […]
China is set to launch an uncrewed Shenzhou spacecraft to the Tiangong space station to provide the Shenzhou-21 astronauts with a means of returning home.
A Falcon 9 launched a joint U.S.-European satellite to monitor sea levels Nov. 17, extending a record of measurements that dates back more than three decades.
Measuring blood flow to the brain is essential for diagnosing and developing treatments for neurological disorders such as stroke, vascular dementia or traumatic brain injury. Performing this measurement non-invasively is challenging, however, and achieved predominantly using costly MRI and nuclear medicine imaging techniques.
Emerging as an alternative, modalities based on optical transcranial measurement are cost-effective and easy to use. In particular, speckle contrast optical spectroscopy (SCOS) – an offshoot of laser speckle contrast imaging, which uses laser light speckles to visualize blood vessels – can measure cerebral blood flow (CBF) with high temporal resolution, typically above 30 Hz, and cerebral blood volume (CBV) through optical signal attenuation.
Researchers at the California Institute of Technology (Caltech) and the Keck School of Medicine’s USC Neurorestoration Center have designed a lightweight SCOS system that accurately measures blood flow to the brain, distinguishing it from blood flow to the scalp. Co-senior author Charles Liu of the Keck School of Medicine and team describe the system and their initial experimentation with it in APL Bioengineering.
Seven simultaneous measurements Detection channels with differing source-to-detector distances monitor blood dynamics in the scalp, skull and brain layers. (Courtesy: CC BY 4.0/APL Bioeng. 10.1063/5.0263953)
The SCOS system consists of a 3D-printed head mount designed for secure placement over the temple region. It holds a single 830 nm laser illumination fibre and seven detector fibres positioned at seven different source-to-detector (S–D) distances (between 0.6 and 2.6 cm) to simultaneously capture blood flow dynamics across layers of the scalp, skull and brain. Fibres with shorter S–D distances acquire shallower optical data from the scalp, while those with greater distances obtain deeper and broader data. The seven channels are synchronized to exhibit identical oscillation frequencies corresponding to the heart rate and cardiac cycle.
When the SCOS system directs the laser light onto a sample, multiple random scattering events occur before the light exits the sample, creating speckles. These speckles, which materialize on rapid timescales, are the result of interference of light travelling along different trajectories. Movement within the sample (of red blood cells, for instance) causes dynamic changes in the speckle field. These changes are captured by a multi-million-pixel camera with a frame rate above 30 frames/s and quantified by calculating the speckle contrast value for each image.
Human testing
The researchers used the SCOS system to perform CBF and CBV measurements in 20 healthy volunteers. To isolate and obtain surface blood dynamics from brain signals, the researchers gently pressed on the superficial temporal artery (a terminal branch of the external carotid artery that supplies blood to the face and scalp) to block blood flow to the scalp.
In tests on the volunteers, when temporal artery blood flow was occluded for 8 s, scalp-sensitive channels exhibited significant decreases in blood flow while brain-sensitive channels showed minimal change, enabling signals from the internal carotid artery that supplies blood to the brain to be clearly distinguished. Additionally, the team found that positioning the detector 2.3 cm or more away from the source allowed for optimal brain blood flow measurement while minimizing interference from the scalp.
“Combined with the simultaneous measurements at seven S–D separations, this approach enables the first quantitative experimental assessment of how scalp and brain signal contributions vary with depth in SCOS-based CBF measurements and, more broadly, in optical measurements,” they write. “This work also provides crucial insights into the optimal device S–D distance configuration for preferentially probing brain signal over scalp signal, with a practical and subject-friendly alternative for evaluating depth sensitivity, and complements more advanced, hardware-intensive strategies such as time-domain gating.”
The researchers are now working to improve the signal-to-noise ratio of the system. They plan to introduce a compact, portable laser and develop a custom-designed extended camera that spans over 3 cm in one dimension, enabling simultaneous and continuous measurement of blood dynamics across S–D distances from 0.5 to 3.5 cm. These design advancements will enhance spatial resolution and enable deeper brain measurements.
“This crucial step will help transition the system into a compact, wearable form suitable for clinical use,” comments Liu. “Importantly, the measurements described in this publication were achieved in human subjects in a very similar manner to how the final device will be used, greatly reducing barriers to clinical application.”
“I believe this study will advance the engineering of SCOS systems and bring us closer to a wearable, clinically practical device for monitoring brain blood flow,” adds co-author Simon Mahler, now at Stevens Institute of Technology. “I am particularly excited about the next stage of this project: developing a wearable SCOS system that can simultaneously measure both scalp and brain blood flow, which will unlock many fascinating new experiments.”
The head of OHB says he is concerned about a planned joint venture among three of his competitors, even as the company sees opportunities from growing European space spending.
The same pulling force that causes “tears” in a glass of wine also shapes embryos. It’s another example of how genes exploit mechanical forces for growth and development.
Sierra Space has completed key testing milestones for its Dream Chaser vehicle as the company explores both civil and national security missions for the spaceplane.
How animals of the Cambrian period experienced the Cambrian Explosion, which shaped life today and could help researchers understand life on other planets.
The Aedes aegypti mosquito that can carry dengue, yellow fever, and Zika was thought to be too reliant on a hot and wet climate to survive in the Mountain West. But now, a population is thriving in Western Colorado.
After a successful second flight of New Glenn, includig landing the booster, Blue Origin is looking to perform its next launch early next year, possibly with the same booster.
SES is adding another servicer to what is already the broadest and busiest satellite life-extension roster in the commercial geostationary orbit market, with five missions now scheduled between 2026 and 2029.
Connexion
SpaceNews
Discover Mag
