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arXiv 1407.7571cond-mat.mes-hallcond-mat.str-el
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受驱动量子线中的能流和能量涨落

Energy current and energy fluctuations in driven quantum wires

Dawid Crivelli, Marcin Mierzejewski, Peter Prelovšek

摘要:

讨论了远离平衡态驱动的孤立量子线中的能流和能量涨落。该系统由相互作用的无自旋费米子组成,并由依赖于时间的磁通量驱动。能量流由能量密度的连续性方程定义,该方程是针对均匀和非均匀系统导出的。由于总能量在被驱动系统中不守恒,连续性方程中包含了代表焦耳热效应的源项。对于短时间和弱驱动,能量流符合线性响应理论。对于较强的磁场或较长的驱动时间,当能量流由于加热效应而逐渐减小时,系统进入准平衡状态。最后,甚至更强的驱动的能量流进行阻尼布洛赫振荡。能量扩散也随着驾驶而增加。然而,这个量在低场状态下的时间依赖性是相当出乎意料的,因为它主要是由驱动时间决定的,而与系统的瞬时能量无关。

英文摘要:

We discuss the energy current and the energy fluctuations in an isolated quantum wire driven far from equilibrium. The system consists of interacting spinless fermions and is driven by a time--dependent magnetic flux. The energy current is defined by the continuity equation for the energy density which is derived both for homogeneous as well as for inhomogeneous systems. Since the total energy is not conserved in the driven system, the continuity equation includes the source terms which are shown to represent the Joule heating effects. For short times and weak drivings the energy current agrees with the linear response theory. For stronger fields or longer times of driving the system enters the quasiequilibrium regime when the energy current gradually diminishes due to the heating effects. Finally, for even stronger driving the energy current is shown to undergo a damped Bloch oscillations. The energy spread also increases upon driving. However, the time--dependence of this quantity in the low field regime is quite unexpected since it is determined mostly by the time of driving being quite independent of the instantaneous energy of the system.

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