Quantum tomography beyond the leading order

TL;DR

This paper proposes a method to incorporate higher-order corrections into quantum tomography by modeling them as backgrounds, demonstrated through Higgs decay analysis relevant for future entanglement tests at the LHC.

Contribution

It introduces a novel approach to handle higher-order effects in quantum tomography by treating them as backgrounds, extending the technique's applicability beyond leading order.

Findings

Successfully modeled higher-order corrections as backgrounds in Higgs decay data

Demonstrated the method's relevance for upcoming quantum entanglement experiments at the LHC

Provides a framework for more accurate quantum state reconstruction in complex scenarios

Abstract

Quantum tomography, as a tool to probe foundational aspects of quantum mechanics, relies on extracting spin information from angular distributions. This is inherently a leading-order technique, ill-defined when higher-order corrections are significant. For those cases, we propose to treat higher-order corrections as a background, to be modeled and subtracted from data in the same way as other backgrounds are. We illustrate this procedure for Higgs decays $H \to ZZ \to e^+ e^- \mu^+ \mu^-$, which is of high interest for upcoming qutrit entanglement tests at the Large Hadron Collider.