Researchers have developed a new computational method, DOCI-QSCI-AFQMC, which accurately simulates complex molecular systems by effectively doubling the number of orbitals considered in standard quantum simulations and overcoming limitations of existing single-reference techniques, as demonstrated through successful modelling of chemical bonds and reactions.
Gold, M., Lin, J., Chitambar, E. et al. Heralded photonic graph states with inefficient quantum emitters. npj Quantum Inf (2026). https://doi.org/10.1038/s41534-026-01181-7
A research team has successfully implemented a programmable spinor lattice on a photonic integrated circuit (PIC). This platform enables the realization of non-Abelian physics, in which the outcome of operations depends on their sequence, within an integrated photonic system.
Through this achievement, the research team led by Prof. Sunkyu Yu and Prof. Namkyoo Park of the Department of Electrical and Computer Engineering, in collaboration with Prof. Xianji Piao of the School of Electrical and Computer Engineering at the University of Seoul and Prof. Jensen Li of the University of Exeter (UK), demonstrates that the operating principles of topological qubits can be classically emulated, and further propose the possibility of realizing novel topological physical phenomena that differ from previously known implementations.
The results of this study were published in Physical Review Letters.
Physicists in Leiden have built a microscope that can measure no fewer than four key properties of a material in a single scan, all with nanoscale precision. The instrument can even examine complete quantum chips, accelerating research and innovation in the field of quantum materials. The study is published in the journal Nano Letters.
Temperature, magnetism, structure, and electrical properties. These are the material characteristics that this new microscope reveals. “It almost feels like having a superpower,” says Matthijs Rog, a Ph.D. student in Kaveh Lahabi’s research group. “You look at a sample and see not only its shape but also the electrical currents, heat, and magnetism within it.”
Kaveh Lahabi, who leads the group, says, “This microscope removes the experimental bottlenecks that have long limited the study of quantum materials. This is not an idealized technique—it works on the systems we actually want to understand. Furthermore, the sensitivity of our measurements tends to impress a lot of my physicist colleagues.”
Physicists have long recognized the value of photonic graph states in quantum information processing. However, the difficulty of making these graph states has left this value largely untapped. In a step forward for the field, researchers from The Grainger College of Engineering at the University of Illinois Urbana-Champaign have proposed a new scheme they term “emit-then-add” for producing highly entangled states of many photons that can work with current hardware. Published in npj Quantum Information, their strategy lays the groundwork for a wide range of quantum enhanced operations including measurement-based quantum computing.
Entanglement is a key driver in delivering faster and more secure computational and information systems. But creating large, entangled states of more than two photons is challenging because the losses inherent in optical systems mean most photon sources have a low probability of successfully producing a photon that survives to the point of detection. Therefore, any attempt to build a large entangled state is full of missing photons, breaking the state apart. And identifying the missing spots would mean attempting detection of the photons, which is a destructive process itself, and precludes going back to fill those spots.
To circumvent this challenge, a team led by Associate Professor of Physics Elizabeth Goldschmidt and Professor of Electrical and Computer Engineering Eric Chitambar began with a different mindset.
Devices that can confine individual electrons are potential building blocks for quantum information systems. But the electrons must be protected from external disturbances. RIKEN researchers have now shown how quantum information encoded into a so-called quantum dot can be negatively affected by nearby quantum dots. This has implications for developing quantum information devices based on quantum dots.
Quantum computers process information using so-called qubits: physical systems whose behavior is governed by the laws of quantum mechanics. An electron, if it can be isolated and controlled, is one example of a qubit platform with great potential.
One way of controlling an electron is to use a quantum dot. These tiny structures trap charged particles using electric fields at the tips of metal electrodes separated by just a few tens of nanometers.
Researchers at QuTech in Delft, The Netherlands, have developed a new chip architecture that could make it easier to test and scale up quantum processors based on semiconductor spin qubits. The platform, called QARPET (Qubit-Array Research Platform for Engineering and Testing) and reported in Nature Electronics, allows hundreds of qubits to be characterized within the same test-chip under the same operating conditions used in quantum computing experiments.
“With such a complex, tightly packed quantum chip, things really start to resemble the traditional semiconductor industry,” states researcher Giordano Scappucci.
When viewed under a microscope, the structure of the QARPET chip appears almost woven. Fabrication was in fact a stress test for engineering capabilities.
How can gravity and the quantum world be unified? What are the different string theories? And what is \.
Researchers have designed and demonstrated an ultraviolet laser that removes a major bottleneck in the development of a nuclear clock.
Whereas ordinary atomic clocks keep time using transitions of electrons in atoms, a prospective nuclear clock would harness a transition between states of the nucleus. Compared with electronic transitions, nuclear ones are much less sensitive to environmental disturbances, which would potentially give nuclear clocks unprecedented precision and stability. Such devices could improve GPS systems and enable more sensitive probes of fundamental physics. The main hurdle has been that nuclear transitions are extremely difficult to drive controllably using existing laser technology. Now Qi Xiao at Tsinghua University in China and colleagues have proposed and realized an intense single-frequency ultraviolet laser that can achieve such driving for thorium-229 nuclei [1, 2]. Beyond timekeeping, the team’s laser platform could find uses across quantum information science, condensed-matter physics, and high-resolution spectroscopy.
For most nuclear transitions, the energy difference between the two states lies in the kilo-electron-volt to mega-electron-volt range. Consequently, such transitions are inaccessible to today’s high-precision lasers, which can deliver photons of typically a few electron volts in energy. A long-known exception is the transition between the ground state and first excited state of thorium-229 nuclei. Indirect measurements over the past 50 years have gradually pinned down that transition’s energy difference to only about 8.4 eV. As a result, this transition is being actively investigated as a candidate for developing a nuclear clock.
The element cobalt is considered a typical ferromagnet with no further secrets. However, an international team led by HZB researcher Dr. Jaime Sánchez-Barriga has now uncovered complex topological features in its electronic structure. Spin-resolved measurements of the band structure (spin-ARPES) at BESSY II revealed entangled energy bands that cross each other along extended paths in specific crystallographic directions, even at room temperature. As a result, cobalt can be considered as a highly tunable and unexpectedly rich topological platform, opening new perspectives for exploiting magnetic topological states in future information technologies.
The findings are published in the journal Communications Materials.
Cobalt is an elementary ferromagnet, and its properties and crystal structure have long been known. However, an international team has now discovered that cobalt hosts an unexpectedly rich topological electronic structure that remains robust at room temperature, revealing a surprising new level of quantum complexity in this material.