Quantum Thermodynamics Allows Quantum Measurement Almost Without Collapse

TL;DR

This paper proposes a quantum measurement method that minimally disturbs the system by leveraging thermodynamic quantities, offering a new perspective on quantum measurement and its foundational paradoxes.

Contribution

It introduces a thermodynamics-based measurement process that retrieves system information with almost no collapse, advancing understanding of quantum measurement and objectivity.

Findings

Measurement characterized by work and heat costs respecting the first law

System state can be retrieved arbitrarily close to original after measurement

Addresses quantum measurement paradoxes like Wigner's friend

Abstract

We introduce a quantum measurement process that is capable of characterizing an unknown state of a system almost without disturbing or collapsing it. The underlying idea is to extract information of a system from the thermodynamic quantities like work(s) and heat in a process, thereby uncovering a fundamental correspondence between information and thermodynamics. We establish an improved notion of information isolation and show that a process is isolated if it respects the first law of quantum thermodynamics for a given set of conserved quantities or charges. The measurement process involves a global unitary evolution of the system, an apparatus, and a battery which supplies work(s). The global unitary respects the first law. The full information about the system is accessed by counting the charge-wise work costs to implement the reduced evolution on the system and the apparatus. After the work costs are determined, the process is undone where a state of the system is retrieved arbitrarily close to the original initial state. The measurement process is also capable of characterizing an unknown quantum operation. Fundamentally, our findings make an important step towards resolving the paradoxes arising from the quantum measurement problem, such as the Wigner's friend paradox, and the issue related to the objective reality of quantum states. We discuss the technological implications of the almost collapse-free measurement process.