Digital quantum simulation of squeezed states via enhanced bosonic encoding in a superconducting quantum processor

Abstract

We present a fully digital approach for simulating single-mode squeezed states on a superconducting quantum processor using an enhanced bosonic encoding strategy. By mapping up to 2^{n} photonic Fock states onto n qubits, our framework leverages Gray-code-based encodings to reduce gate overhead compared to conventional one-hot or binary mappings. We further optimize resource usage by restricting the simulation on Fock states with even number of photons only, effectively doubling the range of photon numbers that can be represented for a given number of qubits. To overcome noise and finite coherence in current hardware, we employ a variational quantum simulation protocol, which adapts shallow, parameterized circuits through iterative optimization. Implemented on the Zuchongzhi-2 superconducting platform, our method demonstrates squeezed-state dynamics across a parameter sweep from vacuum state preparation (r=0) to squeezing levels exceeding the Fock space truncation limit (r>1.63). Experimental results, corroborated by quantum state tomography and Wigner-function analysis, confirm high-fidelity state preparation and demonstrate the potential of Gray-code-inspired techniques for realizing continuous-variable physics on near-term, qubit-based quantum processors.

References in corpus (24)

• A variational eigenvalue solver on a quantum processor
• QuTiP 2: A Python framework for the dynamics of open quantum systems
• Encoding a qubit in an oscillator
• Superconducting Qubits: Current State of Play
• Trapped-Ion Quantum Computing: Progress and Challenges
• Quantum computing with trapped ions
• Strong quantum computational advantage using a superconducting quantum processor
• The Variational Quantum Eigensolver: a review of methods and best practices
• Towards Practical Quantum Variational Algorithms
• Efficient variational quantum simulator incorporating active error minimisation
• Demonstration of multi-qubit entanglement and algorithms on a programmable neutral atom quantum computer
• Blueprint for a Scalable Photonic Fault-Tolerant Quantum Computer
• Resource-efficient digital quantum simulation of $d$-level systems for photonic, vibrational, and spin-$s$ Hamiltonians
• Observing ground-state properties of the Fermi-Hubbard model using a scalable algorithm on a quantum computer
• Calculation of the Green's function on near-term quantum computers
• Improving Hamiltonian encodings with the Gray code
• Quantum Simulations of Physics Problems
• Finding the ground state of the Hubbard model by variational methods on a quantum computer with gate errors
• Effective calculation of the Green's function in the time domain on near-term quantum processors
• Quantum Computer-Aided design of Quantum Optics Hardware
• Digital quantum simulation of beam splitters and squeezing with IBM quantum computers
• Digital simulation of zero-temperature spontaneous symmetry breaking in a superconducting lattice processor
• Validity condition for high-fidelity Digitized Quantum Annealing
• Utilizing Quantum Processor for the Analysis of Strongly Correlated Materials