Quantum Simulation of Light-Front QCD for Jet Quenching in Nuclear Environments

Abstract

We develop a framework to simulate jet quenching in nuclear environments on a quantum computer. The formulation is based on the light-front Hamiltonian dynamics of QCD. The Hamiltonian consists of three parts relevant for jet quenching studies: kinetic, diffusion and splitting terms. In the basis made up of n-particle states in momentum space, the kinetic Hamiltonian is diagonal. Matrices representing the diffusion and splitting parts are sparse. The diffusion part of the Hamiltonian depends on classical background gauge fields, which need to be sampled classically before constructing quantum circuits for the time evolution. The cost of the sampling scales linearly with the time length of the evolution and the momentum grid volume. The framework automatically keeps track of quantum interference and thus it can be applied to study the Landau-Pomeranchuk-Migdal effect in cases with more than two splittings, which is beyond the scope of state-of-the-art analyses, no matter whether the medium is static or expanding, thin or thick, hot or cold. We apply this framework to study a toy model and carry out the quantum simulation by using the IBM Qiskit simulator. The Landau-Pomeranchuk-Migdal effect that suppresses the total radiation probability is observed in the quantum simulation results.

Medium induced jet broadening in a quantum computer

“…Beside field theory based simulations, they have also been applied to specific topics such as nuclear structure [32][33][34][35][36][37], neutrino oscillation [38] and string theory [39]. Concerning collider oriented physics, these technologies have, for example, been used to simulate hard probes like heavy flavors [40] and jets [41,42], optimize parton showers [43][44][45] and jet clustering algorithms [46][47][48] as well as in the detection of quantum anomalies [49] and the study of spin correlations at high energies [50]. Although such applications are still highly constrained by the performance of current quantum computers [51], even the (re)formulation of problems in a language accessible to these machines turns out to be highly non-trivial.…”