Alice & Bob

Superconducting (Cat Qubits) Founded 2020 Paris, France

Overview

Cat qubit technology for fault-tolerant quantum computing. Qubits inherently protected against bit-flip errors, reducing error correction overhead.

Current System: 16 qubits
Funding: Private, raised €30M (Series A)
Website: https://alice-bob.com

Key Milestones

  • 2020: Alice & Bob founded from ENS Paris research
  • 2022: First cat qubit chip demonstrated
  • 2023: Raised €27M Series A (largest French quantum funding)
  • 2024: 16-qubit cat qubit processor with extended coherence

Technology: Cat Qubits

Alice & Bob builds cat qubits—a type of superconducting qubit with built-in error protection. Unlike standard transmon qubits (IBM, Google), cat qubits encode information redundantly to resist bit-flip errors.

How it works:

  • Superposition of two coherent states (Schrödinger’s cat)
  • Autonomous error correction: Hardware-level protection against bit flips
  • Only phase-flip errors remain (easier to correct)

Advantage: Reduces quantum error correction overhead. Standard qubits need ~1,000 physical qubits per logical qubit. Cat qubits aim for ~10-100x reduction.

Fault-Tolerant First Approach

Alice & Bob’s strategy: don’t build NISQ systems. Focus on fault-tolerant quantum computing from the start.

Timeline:

  • 2025: 100-qubit cat qubit system
  • 2027: First error-corrected logical qubits
  • 2030: Utility-scale fault-tolerant system

Similar to PsiQuantum: Skip near-term noisy systems, wait for fault tolerance.

Competitive Position

vs. IBM/Google (transmon qubits):
Alice & Bob claims cat qubits will require fewer physical qubits for error correction. Unproven at scale.

vs. Other Error-Correction Approaches:
Competing with surface codes (IBM), topological codes (Microsoft), and other hardware-based error suppression methods.

Risk: Cat qubits are new technology. If autonomous error correction doesn’t work as advertised, Alice & Bob has no fallback.

French Quantum Ecosystem

Alice & Bob is France’s leading quantum hardware startup. Benefits from:

  • French government quantum funding
  • EU Quantum Flagship program
  • Strong academic partnerships (ENS, Institut d’Optique)

Competition: Pasqal (neutral atoms), Quandela (photonic) also in France.

Applications (When Available)

Once fault-tolerant:

  • Drug discovery (molecular simulation)
  • Cryptography (Shor’s algorithm)
  • Optimization (Grover’s algorithm)
  • Materials science (catalyst design)

Timeline: Not available publicly until late 2020s (fault-tolerant systems).