Modelling Quantum Devices and the Reconstruction of Physics in Practical Systems

TL;DR

This paper investigates the challenges in accurately modeling quantum devices, revealing that complete reconstruction of the device physics requires specific conditions on states, measurements, or evolution operators.

Contribution

It identifies necessary conditions for correctly reconstructing quantum device models, highlighting limitations with limited experimental operations.

Findings

Correct model identification is often impossible with limited operations.

Reconstruction requires either specific pure states and measurements or comprehensive evolution operators.

The paper establishes conditions under which quantum device models can be accurately reconstructed.

Abstract

Modelling quantum devices is to find a model according to quantum theory that can explain the result of experiments in a quantum device. We find that usually we cannot correctly identify the model describing the actual physics of the device regardless of the experimental effort given a limited set of operations. According to sufficient conditions that we find, correctly reconstructing the model requires either a particular set of pure states and projective measurements or a set of evolution operators that can generate all unitary operators.