Variational Gibbs state preparation on trapped-ion devices

2026/03/04 by Reece Robertson, Mirko Consiglio, Josey Stevens +3 · 1 voice · 2 citations
Computer Science · Physics and Astronomy · #Canonical ensemble #Function (biology) #Gibbs free energy #Gibbs state #High fidelity #Ising model #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum and electron transport phenomena #Quantum computer #State (computer science) #Variational method #quant-ph

paper · pdf · doi:10.1038/s41534-026-01318-8

arxiv published 2026/03/04 · arxiv updated 2026/03/04 · openalex publication_date 2026/07/11 · openalex created_date 2026/07/12 · openalex updated_date 2026/08/06

Abstract

We implement a variational quantum algorithm for Gibbs state preparation of a transverse-field Ising model on IonQ’s quantum computers. To this end, we train the variational parameters via classical simulation and perform state tomography on the quantum devices to evaluate the fidelity of the prepared Gibbs state. As a main result, we find that fidelity decreases (non-monotonically) as a function of the inverse temperature β of the system. Fidelity also decreases as a function of the size of the system. Interestingly, we find that a Gibbs state prepared for a specified β is a better representative of a Gibbs state prepared for a lower β ; or in other words, thermal fluctuations in the quantum hardware lead to digital heating, that is, an increase in the temperature of the prepared Gibbs state above what was intended.

Citations

• Noise-Induced Thermalization in Quantum Systems
• The Grand Challenge of Quantum Applications
• Quantum Computing Beyond Ground State Electronic Structure: A Review of Progress Toward Quantum Chemistry Out of the Ground State
• Adiabatic preparation of thermal states and entropy-noise relation on noisy quantum computers
• Learning quantum Gibbs states locally and efficiently
• Efficient Quantum Chemistry Calculations on Noisy Quantum Hardware
• Polynomial Time Quantum Gibbs Sampling for Fermi-Hubbard Model at any Temperature
• Simon's algorithm in the NISQ cloud
• Rapid on-demand generation of thermal states in superconducting quantum circuits
• Study on quantum thermalization from thermal initial states in a superconducting quantum computer
• A survey on the complexity of learning quantum states
• Ground state preparation with shallow variational warm-start
• Thermal Multi-scale Entanglement Renormalization Ansatz for Variational Gibbs State Preparation
• On Quantum Circuits for Discrete Graphical Models
• Adaptive variational algorithms for quantum Gibbs state preparation
• Practical Quantum State Tomography for Gibbs states
• Noise-Assisted Variational Quantum Thermalization
• A Variational Quantum Algorithm for Preparing Quantum Gibbs States

Cited by

• Extending UNIQuE: Quantum Simulation Speedup for the HHL Algorithm
• Fault-Tolerant Error Detection Above Break-Even for Multi-Qubit Gates

Discussions

• What are NISQ computers good for? Well, possibly many things. But definitely for the preparation of Gibbs states: arxiv.org/abs/2603.03801 [bsky, 2 points, 1 comments]

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• Adaptive variational algorithms for quantum Gibbs state preparation
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• Fully optimised variational simulation of a dynamical quantum phase transition on a trapped-ion quantum computer
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• Noise-Assisted Variational Quantum Thermalization