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[손정락 졸업생] 관측 방법에 따른 오토엔진의 성능변화 발견 (Physical Review X - Quantum 논문 게재)

2021-11-10l 조회수 842

“Monitoring Quantum Otto Engines”

 

본교의 손정락 학부생이 참여한 기초과학연구원 복잡계 이론물리 연구단 연구팀이 관측행위가 양자 영역에서 작동하는 오토 열기관의 성능에 미치는 영향을 밝혀냈다.
 
손정락 학생과 Augsburg 대학교 Peter Talkner 교수과학기술연합대학원대학교 Juzar Thingna 교수로 이루어진 연구팀은 특히 최근 새롭게 제안된 반복적 접촉(repeated contacts) 적용해 관측했을  일반적인 관측을 반복한 경우에 비해 엔진이 시간당 내보내는 일의 양인 일률과 엔진의 신뢰성이 모두 상당한 정도로 향상되는 것을 발견했다이는 반복적 접촉에서 양자 상태의 결맞음이 파괴되지 않아 생기는 현상으로 이해된다
 
양자역학의 가장  특징  하나는 관측행위 자체가 양자 상태를 변화시킨다는 것이다이러한 효과는 특히 일이나 열을 정의하기 위해서 관측행위가 필수적인 양자 열역학적 과정에서 문제를 야기할  있다하지만 열기관의 작동과정에 대한 연구에서 관측행위는 많은 경우 무시되어왔다 연구는 양자 열기관의 설계 과정에서 관측과정이 포함되어야 하는 필요성을 증명하고 엔진의 성능을 개선할  있는 새로운 길을 제시한다해당 논문은 Phys. Rev. X Quantum 게재되었다.
 
 
Measurement back-action, where the measurement itself alters the system, is the hallmark of quantum mechanics. This effect might be problematic in quantum thermodynamics, where a diagnostic protocol is needed to define critical quantities such as work and heat. Yet, the process of measurements often has been neglected while studying thermal machines. Motivated by this problem, this work explicitly incorporates the effects of "monitoring" on the performance of quantum Otto engines. In particular, it is discovered that by applying an alternative monitoring procedure (repeated contacts), the power (work output per time) and reliability are both improved substantially compared to the case where conventional measurements are repeatedly performed. This enhancement can be attributed to the quantum coherence preserved within the alternative scheme. In conclusion, this research demonstrates the necessity to incorporate measurement protocols in the study of quantum thermal devices and a new pathway to control engine performance through different monitoring schemes. This work is published in the Phys. Rev. X Quantum.

 

Authors: Jeongrak Son (IBS PCS, 서울대), Peter Talkner (University of Augsburg), Juzar Thingna (IBS PCS, UST)

Link: https://journals.aps.org/prxquantum/abstract/10.1103/PRXQuantum.2.040328

News: https://phys.org/news/2021-11-quantum-otto-affects.html

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