The Daily · Saturday 24 October 2026

The day in brief

Treasury’s October 22 proposal would add quantum-computing software and algorithms linked to covered foreign persons to U.S. investment prohibitions ¹. The draft is open for public comment through December 7, 2026, while existing restrictions remain in force ¹. Ono and Shiozaki say their invariants completely characterize K groups in 159 of 230 space groups ².

NowSecure found no detectable post-quantum cryptography code or libraries in 96.9% of 136,711 iOS and Android apps it analyzed ³. A Waterloo theorem finds Gaussian repeater chains cannot raise quantum or private capacity above direct transmission over a pure-loss optical channel ⁴. A transmon experiment found nonlinear evolution in selected no-jump histories, while the full three-level system remained linear ⁵.

A proof-of-principle transmitter-independent QKD experiment reported an asymptotic key rate of 410 bits per second over 27 kilometers of spool fiber ⁶. ZuriQ and Rhonexum announced a multi-year commercial framework agreement covering cryogenic integrated-circuit technologies for ZuriQ to evaluate ⁷. Phasecraft researchers reported cost reductions of up to 73% across three quantum-simulation compilation tasks using AI agents and frozen verifiers ⁹.

The five

• Treasury Proposes Wider Controls on Quantum Investment

  A Treasury proposal would extend U.S. outbound investment prohibitions to more quantum-computing software and algorithms linked to covered foreign persons. The draft is open for comment through December 7, 2026, while existing restrictions remain in force.

  Source · U.S. Department of the Treasury

• Ono and Shiozaki Map Superconductor Topology in 159 Space Groups

  Seishiro Ono and Ken Shiozaki present a method for constructing topological invariants using the Atiyah-Hirzebruch spectral sequence. Applied to time-reversal-symmetric spinful superconductors with conventional pairing, their invariants completely characterize K groups in 159 space groups.

  Source · American Physical Society

• NowSecure Finds 97% of 136,711 Mobile Apps Lack Detectable PQC

  NowSecure’s analysis of 136,711 iOS and Android apps found that 96.9% had no detectable post-quantum cryptography code or libraries. The company also flagged more than 3,100 apps using weak encryption, while cautioning that its binary scan cannot establish whether detected code runs.

  Source · NowSecure

• Waterloo Researchers Set a Direct-Link Ceiling for Gaussian Repeaters

  A Physical Review Letters paper by University of Waterloo researchers finds that Gaussian repeater chains cannot beat direct transmission over a pure-loss optical channel. The proof covers Gaussian operations, homodyne measurements and classical communication, and introduces a fractional-extendibility method for analyzing the limit.

  Source · Physical Review Letters

• Superconducting Qubit Experiment Shows Postselection Breaks Linearity

  A superconducting transmon experiment finds nonlinear evolution in a subset of quantum measurement histories selected for having no quantum jumps. The full three-level system, counted without that filtering, retains linear evolution.

  Source · Nonlinear quantum evolution of a dissipative superconducting qubit

Also today

• Researchers Demonstrate Transmitter-Independent QKD Over 27 km
• ZuriQ and Rhonexum Target Trapped-Ion Control Wiring
• Shao and Motter Rework Entanglement Percolation
• Phasecraft AI Agents Cut Costs Across Three Quantum Benchmarks
• Gonçalves, Yang and Lin Find a Route to Chiral Pairing
• UChicago Model Finds Hidden Energy Loss in Silicon-Carbide Defects
• TRIO Pulses Keep X Gates Above 99.5% Under Control Errors
• Three Users Share a QKD Network Through a Passive Circulator Hub
• Researchers Extend Bell Tests to Certify Majorana Operators
• Harvard Physicists Set Out Exponential Speedups for Signal Sensing
• Fraunhofer Team Switches Off NV Laser for 100% Magnetic Contrast
• IBM Quantum Drew 65 of 80 Teams in Japan’s NEDO Challenge
• Florida Switches On Its First Quantum-Safe Network Link
• PRX Quantum Paper Automates Boundaries for Planar Quantum Codes
• GaAs Triple Dot Delivers 4.05-Nanosecond Spin Gates
• Innsbruck Team Reports Trapped-Ion Gate Errors Below 0.5%
• Cloudflare Puts Post-Quantum GeoKey Manager Into Closed Beta

The paper of the day

• Automating quantum circuit optimization with AI agents

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