有限温度下介观LC电路中的量子涨落

Quantum fluctuations of mesoscopic LC circuit at finite temperature

在有限温度下,介观电路系统实际上并不处在一个确定的量子状态,而是处在混合态。利用量子正则系综理论研究了介观LC电路在混合态下电荷和电流的量子涨落。结果表明,有限温度下介观LC电路中的量子涨落不仅与电路器件参数有关,而且与温度也有关。温度越高,电路中的量子涨落越大。该方法较热场动力学(TFD)方法更易于理解和应用。由于实际的介观电路总是处在有限温度下,所以其结论对控制介观电路中的量子涨落有一定的实际意义。

At a definite temperature, a mesoscopic circuit isn＇t in a determinate quantum state, but in the mixed state. Using the quantum canonic ensemble theory, the quantum fluctuations of charge and circuit of a mesoscopic LC circuit in the mixed state were studied. It is shown that the quantum fluctuations of a mesoscopic LC circuit depend on not only the circuit component parameters, but also the temperature. The higher the temperature, the more quantum noise the mesoscopic LC exhibits. This method is more easily understood and applied than the TFD method. As the mesoscopic circuit is always at finite temperatures, the result is useful for controlling the quantum fluctuations of mesoscopic circuit.