deterministic-cat-state-generation

name	deterministic-cat-state-generation
description	Deterministic generation of large cat states (100+ photons) using dynamical invariants of hybrid qubit-bosonic systems under time-dependent Hamiltonians. Universal quantum control theory for quantum metrology and fault-tolerant computation. arXiv:2606.03293.
metadata	{"arxiv_id":"2606.03293","category":"quant-ph","published":"2026-06-02"}

Deterministic Generation of Cat States with More Than 100 Photons Under Dissipation

arXiv: 2606.03293 (June 2026)

Problem

Large-size cat states are fundamental for exploring quantum-to-classical transitions and are promising resources for quantum metrology and fault-tolerant quantum computation. However, amplifying cat state magnitude is challenging due to growing fragility under decoherence.

Solution

Dynamical Invariant-Based Control:

• Uses dynamical invariants of hybrid qubit-bosonic systems
• Works under both Hermitian and non-Hermitian time-dependent Hamiltonians
• Applies Universal Quantum Control (UQC) theory for system dynamics analysis
• Deterministic generation (not probabilistic or post-selected)

Key Results

• Scale: Cat states with 100+ photons
• Method: Dynamical invariant engineering under time-dependent control
• Robustness: Operates under dissipation (decoherence present)
• Framework: Universal Quantum Control theory applies to broad class of systems

Reusable Patterns

Pattern 1: Dynamical Invariant Engineering

Use dynamical invariants to steer quantum systems to desired states:

1. Identify target state (e.g., cat state of size α)
2. Construct dynamical invariant that has target state as eigenstate
3. Design time-dependent Hamiltonian that preserves the invariant
4. System evolves deterministically to target regardless of initial state

Pattern 2: Hybrid Qubit-Bosonic Control

Leverage hybrid systems combining discrete (qubit) and continuous (bosonic) variables:

• Qubit provides discrete control degrees of freedom
• Bosonic mode provides large Hilbert space for encoding
• Coupling enables deterministic state preparation in bosonic subspace

Pattern 3: Non-Hermitian Quantum Control

Exploit non-Hermitian Hamiltonians for enhanced control:

• Dissipation can be engineered as a resource, not just a nuisance
• Non-Hermitian dynamics enable faster state preparation
• Effective for large-state generation where Hermitian-only approaches are too slow

Applications

• Quantum metrology: Large cat states for Heisenberg-limited sensing
• Fault-tolerant QC: Cat states as logical qubits in bosonic QEC codes
• Quantum-to-classical transition: Study decoherence at macroscopic scales
• Universal QC: Cat states as resources for universal gate sets

Activation

cat states, bosonic codes, dynamical invariants, universal quantum control, quantum metrology, fault-tolerant quantum computation, hybrid qubit-bosonic, non-Hermitian Hamiltonian, deterministic state preparation

Related Skills

• quantum-control-engineering - Quantum control patterns
• bosonic-grid-states-qec - Bosonic QEC codes
• universal-robust-quantum-control - Noise-agnostic quantum control