Prospects for quantum process tomography at high energies

TL;DR

This paper explores quantum process tomography in high-energy collider experiments, proposing a method to reconstruct quantum channels from experimental data, which could test the Standard Model extensions and foundational quantum mechanics.

Contribution

It introduces a novel application of quantum process tomography to collider physics, linking quantum information techniques with high-energy experimental analysis.

Findings

Quantum channels can be reconstructed from collider data.

Quantum process tomography can probe physics beyond the Standard Model.

The approach provides a new test of quantum mechanics in high-energy processes.

Abstract

In quantum information theory, the evolution of an open quantum system -- a unitary evolution followed by a measurement -- is described by a quantum channel or, more generally, a quantum instrument. In this work, we formulate spin and flavour measurements in collider experiments as quantum instruments. We demonstrate that the Choi matrix, which completely determines input-output transitions, can be both theoretically computed from a given model and experimentally reconstructed from a set of final state measurements (quantum state tomography) using varied input states. The experimental reconstruction of the Choi matrix, known as quantum process tomography, offers a powerful new approach for probing potential extensions of the Standard Model within the quantum field theory framework and, at the same time, constitutes a new foundational test of quantum mechanics itself. As an example, we outline the quantum process tomography approach applied to the $e^+ e^- \to t \bar{t}$ process at a polarized lepton collider.