Quantum simulation of Jet Evolution and Parton Structure

Project Information

Q-JEPS

Grant agreement ID: 101109293

DOI

10.3030/101109293

Project closed

EC signature date 3 April 2023

Start date 1 June 2023

End date 31 May 2025

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 181 152,96

Coordinated by

UNIVERSIDAD DE SANTIAGO DE COMPOSTELA
Spain

Periodic Reporting for period 1 - Q-JEPS (Quantum simulation of Jet Evolution and Parton Structure)

Reporting period: 2023-06-01 to 2025-05-31

Summary of the context and overall objectives of the project

The Q-JEPS project addresses one of the grand challenges in particle physics: simulating the behavior of strongly interacting particles, such as quarks and gluons, in extreme environments like those created in high-energy collisions at the Large Hadron Collider (LHC) or future Electron-Ion Collider (EIC). These interactions are governed by quantum chromodynamics (QCD), but solving QCD in real-time and in dense media remains one of the hardest problems in theoretical physics.

At the same time, quantum computing is rapidly emerging as a transformative technology for solving certain classes of problems beyond the capabilities of classical computers. Q-JEPS brings these two worlds together. It pioneers the application of quantum algorithms to simulate jet evolution — cascades of particles resulting from high-energy collisions — and the internal structure of hadrons like protons and pions.

The project’s goal was to discover or build an efficient quantum simulation framework that can model multi-parton jets, their interactions with a dense medium, and compute key observables such as momentum broadening, gluon radiation, entropy growth, and also find a path to compute nonperturbative quantities like parton distribution functions (PDFs) from first-principle. By doing so, Q-JEPS aims to lay the groundwork for a new generation of quantum simulations for fundamental physics, with long-term impacts on how we interpret data from particle accelerators and understand the early universe.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The project progressed through four key scientific work packages:

Multi-jet simulation on quantum devices: Using the light-front Hamiltonian formalism, Q-JEPS constructed and simulated three-particle quark-gluon Fock states on quantum circuits, going beyond the two-particle targets originally planned. The simulations, performed using IBM Qiskit and high-performance tensor network backends, revealed how jet energy loss and gluon production emerge in dense QCD matter. This work resulted in two peer-reviewed publications in Physical Review D. An extension to heavy quark simulation framework was also published in Physical Review D.

Modeling a dynamic thermal medium: A novel approach was developed to encode a quantum medium using unitary operators and variational circuits. This work resulted in two peer-reviewed publications in Journal of High Energy Physics. They also enabled the simulation of real-time thermalization (ongoing).

Simulating hadron structure with quantum algorithms: During a secondment at UCLA, I implemented quantum imaginary time evolution and tensor network methods to extract PDFs in the Nambu–Jona-Lasinio model. This marked a step toward practical quantum simulations of partonic structure in nucleons and the paper is currently under review. This collaboration also sparkled two additional projects that are currently ongoing (scattering of mesons in first principle and computing hadronic tensor)

Software framework (ongoing): A modular open-source toolkit has been developed to enable researchers to simulate jets, construct Hamiltonians, evolve quantum states, and extract observables. The code and supporting documentation will be released via GitHub and arXiv at project completion.

Q-JEPS has produced 7 peer-reviewed publications in total (excluding conference proceedings), with additional manuscripts in preparation, and received widespread attention through conference presentations, workshops, and international collaborations.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Q-JEPS represents the first systematic application of quantum computing to simulate multi-particle jets interacting with a QCD medium. The results significantly go beyond the state of the art by:

- Enabling real-time simulations of non-Abelian gauge theories in a medium using quantum circuits.

- Encoding QCD-like Fock spaces efficiently on quantum hardware with more than 100 qubits.

- Introducing a scalable model of jet-medium suitable for current and near-term quantum processors.

- Providing practical frameworks for computing PDFs on quantum simulators — an essential ingredient for interpreting collider experiments.

The project has identified several areas for future uptake and success:

- Further research is needed to reduce quantum circuit depth, especially for NISQ devices.

- Integration of noise-robust encodings and quantum error correction techniques will be critical for scaling.

- Internationalization and interdisciplinary collaboration (HEP + quantum information) will accelerate adoption.

- Sustained EU investment and support for hybrid quantum-classical infrastructure will be necessary to move toward demonstration-scale simulations relevant to LHC and EIC physics.

The project's open-source framework and reproducible data models are expected to serve as reference tools for future simulations in both quantum field theory and quantum computing applications.