The second law of thermodynamics states that heat naturally flows from a hot reservoir to a cold one. Traditionally, this heat flow can be reversed using Maxwell demon, which requires acquiring information during the measurement process and implementing feedback control. However, quantum measurement-based cooling eliminates the need for feedback and instead manipulates energy flow solely by choosing specific measurement bases. Despite its theoretical foundation, experimental verification of this mechanism has been lacking, particularly regarding the role of quantum entanglement.
Recently, Professor Peng Xue's team from the Beijing Computational Science Research Center published an article titled "Quantum cooling engine fueled by quantum measurements" in Science Bulletin. The research team employed a linear optical platform to simulate a two-stroke, two-qubit engine. In the experiment, they demonstrated various quantum thermodynamic processes by tuning the energy level spacing of the working substance and adjusting the temperature parameters of the bath. They successfully realized a quantum cooling engine driven by quantum measurements and discovered the influence of entanglement on the energy exchange between the working substance and the measurement apparatus.
Science Bulletin