Simulating boson-matter interactions previously required thousands of physical qubits for similar boson-matter interaction simulations; however, the binary quadrature encoding achieves an efficient balance between space and time complexity using just (56 qubits) in experiments with Quantinuum’s H2-2 trapped-ion device. A novel Dicke encoding creates very shallow circuits but demands sharply more qubits than other methods tested. Binary quadrature encoding is most favourable overall due to its use of the quantum Fourier transform.

The team assessed different methods for representing continuous properties, like light or vibration, using quantum computers’ discrete bits; they compared how many processing steps and fundamental units of quantum information each method requires. The newly introduced Dicke encoding creates simpler circuits but needs significantly more qubits than other approaches tested, making it less favourable overall due to its resource intensity.

Researchers at Delft Institute of Applied Mathematics and QuTech compared methods for representing continuous properties like light or vibration using quantum computers’ discrete bits; they focused on how many processing steps and fundamental units of quantum information each method requires. They assessed unary Fock state encoding, an unexplored Dicke state encoding, where multiple identical coins flipped together represent collective states, and binary quadrature encoding which uses the quantum Fourier transform.

Experiments utilising Quantinuum’s H2-2 device with (56 qubits) demonstrated that binary quadrature encoding effectively balances resource demands while a new Dicke encoding creates simpler circuits but needs significantly more qubits overall. Like building a complex structure layer by layer, circuit depth is key to efficient computation; shallower circuits are generally preferred. The team found noise led to deviations from ideal behaviour in their experiments, prompting them to ask whether this impacts logical qubit performance and error correction strategies.

Binary Quadrature Encoding Enables Scalable Boson Simulations on Trapped Ions

Physicists at Quantinuum used their H2-2 trapped-ion device, comprising (56 qubits), to achieve displacement and Dicke model simulations previously limited by resource constraints. An efficient binary quadrature encoding reduced the number of physical qubits needed per logical qubit, balancing space efficiency with reasonable time complexity through use of the quantum Fourier transform. This represents an improvement over prior techniques that demanded thousands of qubits for similar boson-matter interaction simulations; however, initial experiments revealed noise sensitivity impacting accuracy in low boson number regimes, requiring further investigation into error correction strategies.

Quantinuum’s H2-2 device demonstrated both displacement and Dicke model simulations using this method. Classical modelling showed their favoured binary quadrature encoding requires fewer circuit operations than other methods for equivalent boson-matter interactions, specifically achieving both space efficiency and reasonable time complexity when simulating these dynamics. Initial tests on the trapped-ion device highlighted that deviations from ideal behaviour were observed early in simulation at low boson numbers, stressing a need for strong error correction techniques to realise practical applications with larger systems.

Early Boson Simulations Highlight Noise Challenges For Scalable Quantum Computation

Binary quadrature encoding offers an appealing balance of space and computational efficiency, allowing boson behaviour simulation on Quantinuum’s hardware, but initial device tests revealed concerning sensitivity to noise. Even in these early “low boson number” regimes, deviations from expected circuit dynamics emerged, raising questions about how effectively this method will scale with more complex systems or longer computations where errors accumulate rapidly. Despite these indications of noise sensitivity, the exploration into encoding methods for simulating bosons, particles important to modelling many physical phenomena, remains valuable on real quantum hardware.

The team compared methods representing continuous properties like light or vibrations using quantum bits; they assessed processing steps and fundamental units of quantum information each approach requires. Unary Fock state, a new “Dicke” encoding utilising collective states, and binary quadrature, which employs the quantum Fourier transform to efficiently map wave-like characteristics onto qubits, were all evaluated. Their detailed comparison provides a vital benchmark against which future improvements in error correction can be measured.

Using classical simulations and a 56-qubit trapped-ion device, researchers compared three ways of representing boson behaviour with qubits: unary, Dicke, and binary quadrature encodings. They found that binary quadrature encoding was most efficient overall regarding both qubit use and circuit complexity; while the novel Dicke encoding created very shallow circuits but required significantly more qubits. This work provides a benchmark for evaluating future improvements in quantum simulation methods.

👉 More information
🗞 Encoding a bosonic mode into qubits for simulating boson-matter interactions
✍️ Maarten Stroeks and Barbara Terhal (Affiliation: Delft Institute of Applied Mathematics & QuTech); Jelena Mackeprang (Affiliation: QuSoft and CWI); Yaroslav Herasymenko (Affiliation: Perimeter Institute for Theoretical Physics)
🧠 ArXiv: https://arxiv.org/abs/2610.29762

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