Department of Physics, Georgetown University, 37th and O Sts. NW, Washington, DC 20057 USA.
Sci Rep. 2014 Apr 16;4:4699. doi: 10.1038/srep04699.
There is much interest in how quantum systems thermalize after a sudden change, because unitary evolution should preclude thermalization. The eigenstate thermalization hypothesis resolves this because all observables for quantum states in a small energy window have essentially the same value; it is violated for integrable systems due to the infinite number of conserved quantities. Here, we show that when a system is driven by a DC electric field there are five generic behaviors: (i) monotonic or (ii) oscillatory approach to an infinite-temperature steady state; (iii) monotonic or (iv) oscillatory approach to a nonthermal steady state; or (v) evolution to an oscillatory state. Examining the Hubbard model (which thermalizes under a quench) and the Falicov-Kimball model (which does not), we find both exhibit scenarios (i-iv), while only Hubbard shows scenario (v). This shows richer behavior than in interaction quenches and integrability in the absence of a field plays no role.
人们对量子系统在突然变化后如何热化非常感兴趣，因为幺正演化应该排除热化。本征态热化假说解决了这个问题，因为在小能量窗口中量子态的所有可观测量具有基本相同的值；对于可积系统来说，由于存在无限数量的守恒量，这一假说被违反。在这里，我们表明，当系统受到直流电场驱动时，存在五种通用行为：（i）单调或（ii）振荡到无限温度稳态；（iii）单调或（iv）振荡到非热稳态；或（v）演化到振荡状态。通过检查哈伯模型（在淬火下热化）和法利科夫-金博尔模型（不热化），我们发现这两个模型都表现出了情况（i-iv），而只有哈伯模型表现出了情况（v）。这表明了比相互作用淬火更丰富的行为，并且在没有场的情况下，可积性没有作用。
