Work

Cooling a Qubit Using n Others

Year: 2025

Type: article

Abstract: In the task of unitarily cooling a quantum system with access to a larger quantum system, known as the machine or reservoir, ? Focusing on the task of cooling a single qubit given access to n separable, thermal qubits with arbitrary energy structure, we answer these questions by giving two new perspectives on this task. First, we show that a set of inequalities related to the energetic structure of the n -qubit machine determines the protocol which cools the qubit to the coldest reachable state, which parts of the machine contribute to this protocol and give rise to a Carnot-like bound. Second, we show that cooling protocols can be represented as perfect matchings on bipartite graphs enabling the optimization of cost functions, e.g., gate complexity or dissipation. Our results generalize the algorithmic cooling problem, establish new fundamental bounds on quantum cooling and offer a framework for designing novel autonomous thermal machines and cooling algorithms.

Source: PRX Quantum

DOI: 10.1103/hrph-dbv7

Authors: Jake Xuereb, Benjamin Stratton, Alberto Rolandi, Jinming He, Marcus Huber, Pharnam Bakhshinezhad

Institutions: Vienna Center for Quantum Science and Technology, University of Bristol, University of Science and Technology of China, Austrian Academy of Sciences

Language: English

Topic: Advanced Thermodynamics and Statistical Mechanics

Subfield: Statistical and Nonlinear Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $3,450

Funders: Österreichische Forschungsförderungsgesellschaft, Bundesministerium für Bildung, Wissenschaft und Forschung, Engineering and Physical Sciences Research Council