The Daily · Thursday 29 October 2026

The day in brief

IQM said it prepared a Greenberger–Horne–Zeilinger state across all 54 qubits on its cloud-accessible Emerald processor ². The company reported a fidelity of 0.516 with readout error mitigation and says cloud customers can use the full-chip performance ². Researchers demonstrated a single carbene molecule combining optical spin readout with millisecond-scale coherence at 4.5 K ¹.

The UK’s 15-year Quantum Technology Roadmap for Space sets priorities for moving quantum systems towards space use by 2040 ³. Alice & Bob researchers estimate that factoring RSA-2048 would require 22,593 physical cat qubits and 3.14 days, under a noise model that assumes no bit-flips ⁴. Zachary Bogorad and Roni Harnik derive limits linking a detector’s coherent response to entanglement among its subsystems ⁵.

A SLAC-led team detected a chiral magnetic structure in MnTe, providing direct evidence that the material is an altermagnet ⁶. BTQ made QPerfect’s MIMIQ emulator available through qBraid’s managed API to a community of more than 35,000 developers ⁷. Researchers report a silicon-based single-photon source at 1217 nanometers with a saturated count rate of 1.29 million per second ⁹.

The five

• Researchers Demonstrate a Single-Molecule Spin–Photon Interface

  Researchers report a carbene molecule that combines optical spin readout with millisecond-scale coherence at 4.5 K. The work demonstrates single-molecule addressability, while photon emission efficiency remains a limitation.

  Source · Nature

• IQM Entangles All 54 Qubits on Its Emerald Processor

  IQM says its cloud-accessible Emerald quantum computer prepared a Greenberger–Horne–Zeilinger state across all 54 qubits at once. The company reports a fidelity of 0.516 with readout error mitigation and says cloud customers can use the full-chip performance.

  Source · IQM Quantum Computers

• UK Sets 15-Year Route to Put Quantum Systems in Space

  The UK’s Quantum Technology Roadmap for Space sets priorities for moving quantum timing, sensing and secure communications from prototypes towards space use by 2040. Published on 27 October, it lays out three development horizons and calls for flight demonstrations, stronger qualification capacity and supply-chain investment.

  Source · GOV.UK

• Alice & Bob Estimates 22,593 Cat Qubits for RSA-2048

  Alice & Bob researchers estimate that a fault-tolerant cat-qubit computer could factor RSA-2048 with 22,593 physical qubits in 3.14 days. The estimate depends on demanding error assumptions, including no bit-flips, and describes a machine that has not been built.

  Source · IACR Cryptology ePrint Archive

• Bogorad and Harnik Tie Coherent Detector Gain to Entanglement

  Zachary Bogorad and Roni Harnik derive limits connecting a detector’s coherent response to entanglement among its subsystems. Their analysis covers quantum parameter estimation and scattering, and distinguishes a strong interaction rate from a signal a detector can actually identify.

  Source · arXiv

Also today

• SLAC Team Finds Direct Evidence of Altermagnetism in MnTe
• BTQ Brings MIMIQ to qBraid’s 35,000 Developers
• WSe₂–WS₂ Chip Delivers 357,000 Single Photons per Second
• Silicon Cavity Records 1.29 Million Photon Counts per Second
• Princeton Team Uses Rydberg Blockade to Speed Ytterbium Loading
• Mamba Decoder Cuts QEC Scaling to O(d²) in Real-Time Simulations
• Aarhus Spectrometer Learns DNP Pulses on the Sample

The paper of the day

• Quantum Evolution Kernel for Node-Attributed Graphs

Every issue

1. Sunday 1 November 2026 — Luthra and Owens Demonstrate QLDPC Surgery on Quantinuum H2-2
2. Saturday 31 October 2026 — IDEMIA Wins First EMVCo Certification for PQC Payment Cards
3. Friday 30 October 2026 — One Transmon Connects Two Superconducting Waveguides
4. Thursday 29 October 2026 — Researchers Demonstrate a Single-Molecule Spin–Photon Interface
5. Wednesday 28 October 2026 — USTC Researchers Demonstrate Four-Way Multiplexed Quantum Gates
6. Tuesday 27 October 2026 — IBM Team Entangles Logical Qubits on Nighthawk Processor
7. Monday 26 October 2026 — Intel Agrees to Acquire Classiq for Full-Stack Quantum Computing
8. Sunday 25 October 2026 — Treasury Proposes Wider Controls on Quantum Investment
9. Saturday 24 October 2026 — Treasury Proposes Wider Controls on Quantum Investment
10. Friday 23 October 2026 — Single-Ion Error Correction Extends Qubit Lifetime 12.9-Fold
11. Thursday 22 October 2026 — Oxford Stores Remote Ion Entanglement in Calcium for 10 Seconds