The Daily · Friday 23 October 2026

The day in brief

A trapped-ion experiment extended a logical qubit’s lifetime to 11.6 milliseconds under deliberately added magnetic noise, about 12.9 times the lifetime of the best physical qubit tested ¹. Stony Brook researchers proved that quantum algorithms need at least Ω(2^(n/24)) queries to produce an entrance-to-exit path through a welded tree of height n with constant probability ².

A transmitter-device-independent quantum key distribution test achieved an asymptotic key rate of 410 bits per second over 27 kilometers of spool fiber ³. Quantinuum and Oracle opened a beta for selected organizations to evaluate Helios through Oracle Cloud Infrastructure ⁴. A Technion-led team reports electron-current bursts lasting 860 attoseconds in a scanning tunnelling microscope junction ⁵.

Federal agencies’ October 22 deadline to submit post-quantum cryptography migration plans passed, but whether they filed on time remains unclear ⁷. A study reports transmon gates in 6.8 nanoseconds with fidelities above 99.98% ⁹.

The five

• Single-Ion Error Correction Extends Qubit Lifetime 12.9-Fold

  A trapped-ion team reports autonomous quantum error correction that extended a logical qubit’s lifetime to 11.6 milliseconds under injected magnetic noise. The result exceeded the best physical-qubit lifetime without measurement or real-time feedback.

  Source · Nature Physics

• Stony Brook Proves Quantum Algorithms Need Exponential Queries for Welded-Tree Paths

  A Stony Brook proof shows that quantum algorithms need at least Ω(2^(n/24)) queries to find a path through a welded tree of height n, even though a quantum walk can find the exit exponentially faster than classical algorithms. A second proof appeared days later, and the research teams are working to determine the optimal lower bound.

  Source · arXiv

• Researchers Demonstrate Transmitter-Independent QKD Over 27 km

  A team led by Qiang Zeng reports a transmitter-device-independent quantum key distribution protocol in Physical Review Applied. Their proof-of-principle test achieved an asymptotic key rate of 410 bits per second over 27 kilometers of spool fiber.

  Source · Physical Review Applied

• Quantinuum and Oracle Open Helios Beta to Selected Cloud Users

  Quantinuum says Oracle’s Quantum AI Compute beta is accepting applications from selected organizations seeking cloud access to its Helios quantum computer. The free preview is for evaluation, not production, and Oracle says places are limited.

  Source · Quantinuum

• Technion Team Steers STM Electrons in 860-Attosecond Bursts

  A Technion-led team used two-color infrared pulses to control electron flow through a scanning tunnelling microscope junction. The researchers report a theory-derived burst duration of 860 attoseconds, with 2-nanometer lateral resolution and sub-ångström height sensitivity.

  Source · Technion – Israel Institute of Technology

Also today

• Federal PQC Plan Deadline Passes, Compliance Still Unclear
• Fan and Pang Target Two Precision Limits in Quantum Thermometry
• Jülich Team Shapes Transmon Pulses for 6.8-Nanosecond Gates
• Alice & Bob’s Squeezed Cat Qubits Cut Bit Flips 160-Fold
• 125-Qubit Processor Teleports Surface-Code States at Distance Seven
• Google Opens $150,000 Contest to Shrink Quantum Circuits
• Correlated Decoding Can Cost Surface Codes Effective Distance
• QuantrolOx Raises €12 Million to Scale Quantum-Control Software
• Northwestern Team Traps One Positron in a Quantum Cyclotron
• Quandela Names Quang Trung University for Vietnam’s First Quantum Computer
• Schrödinger’s Unpublished Hidden-Variable Model Surfaces
• QSolid Tests Its 30-Qubit Processor as 10-Qubit System Opens Access
• Wei and Pang Develop Adaptive Control for Multi-Parameter Sensing
• New York Study Puts State Second in Three Quantum Measures
• Fuzhou Team Tracks Decoherence Across Eight Environmental Qubits
• Zirconium Aryloxides Demonstrate Coherent Control for Qudits
• Floquet-ADAPT-VQE Targets Quasienergies in Driven Systems
• Southeast University Team Demonstrates Quantum Mpemba Effect in a Qubit
• MITRE and Oak Ridge Launch a Joint Computing Institute
• SEEQC Reports 50% QEC Gains in a Simulated Decoder Stack
• Andreev-Qubit Proposal Uses Supercurrent to Skip Ancillas
• UCLA Team Uses Arginine to Stabilize TaS₂’s Quantum Order at 330 K
• NQCC Completes Deployment of Seven Quantum Testbeds
• Alice & Bob Team Maps a Dissipative Phase Diagram with 7x Fewer Solves

The paper of the day

• FVQKD: A Formal Verification of Quantum Key Distribution Security in Rocq

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