Wehrl熵和介观电路量子效应之间的关系  

Relation Between the Wehrl Entropy and the Quantum Effects of Mesoscopic Circuit

作　　者：王帅[1] 徐兴磊[1] 

机构地区：[1]菏泽学院物理系,量子信息与计算重点实验室,山东菏泽274015

出　　处：《厦门大学学报（自然科学版）》2008年第5期662-664,共3页Journal of Xiamen University：Natural Science

基　　金：山东省高等学校实验技术基金(S04W138);菏泽学院自然科学基金(XY07WL01)资助

摘　　要：为了研究介观电路在有限温度下的量子效应,将Wehrl熵应用于介观电路系统中.首先,由量子正则系综理论得到了热场中一维谐振子的密度矩阵,进而计算出的Wehrl熵不仅与谐振子的本征频率有关,而且还随热场的温度单调递增.其次,将介观RLC串联电路等效成热场中的一维谐振子,利用Wehrl熵研究介观RLC串联电路在能量混合态下的量子效应,得出了电路中电荷和自感磁通量的量子涨落及相应不确定关系都随着Wehrl熵单调递增,从而也就随温度单调递增.结论与目前采用热场动力学理论方法所得结果相一致.所以,Wehrl熵可以作为介观电路中的量子涨落和相应不确定关系的度量.By using the quantum canonic ensemble theory, the density matrix and the Wehrl entropy of a harmonic oscillator are derived in a thermal field. The mesoscopic RLC series circuit is equivalent to a harmonic oscillator. The relation between the Wehrl entropy and the quantum effects of mesoscopic circuit is proposed at a finite temperature. It is shown that the Wehrl entropy of a harmonic oscillator not only depends on the eigenfrequency,but also relies on the temperature. The quantum fluctuations of charge,magnetic flux and the corresponding uncertainty relation increase monotonously with the Wehrl entropy, thereby increase monotonously with the temperature,and consistent with results of the thermal field dynamics （TFD）. So the Wehrl entropy can be regarded as a measurement of the quantum effects of the mesoscopic circuit.

关 键 词：WEHRL熵 量子正则系综理论 谐振子 介观RLC电路 量子涨落 

分 类 号：O431.2[机械工程—光学工程]