Dynamical effects of counter-rotating couplings on interference between driving and dissipation
Dynamical effects of counter-rotating couplings on interference between driving and dissipation
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DOI：
10.1103/physreva.90.053850
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发表时间：
2014-11
影响因子：
2.9
通讯作者：
Yiying Yan;Z. Lü;Hang Zheng
中科院分区：
文献类型：
--
作者：
Yiying Yan;Z. Lü;Hang Zheng
用解析方法研究了谐波驱动下二能级系统的耗散动力学。该方法是基于酉变换和Born\char21{}马尔可夫主方程方法的组合。我们的主要目的是澄清驱动和TLS浴（耗散）耦合的反向旋转（CR）项对动力学的影响，并与不同方案的行波结果进行比较，即，在传统的行波近似方法的基础上，又引入了两种特殊的近似方法：一种只考虑了驱动CR项的影响，另一种考虑了耗散CR项的影响。我们的主要结果如下：（i）通过计算含时的布居差和相干性，在共振强驱动的情况下，我们证明了驱动和耗散耦合的CR项对弛豫和退相过程以及定态性质都起着重要作用;（ii）在大失谐驱动的情况下，耗散耦合的CR项可以忽略不计，而驱动的CR项对时间演化和稳态的贡献占主导地位。此外，我们研究了在大失谐强驱动下，耗散对隧穿相干破坏的影响。我们表明，几乎完全抑制的隧道可以实现一个相对较长的时间;（iii）在一定的条件下，我们发现两个特定的方法之一和Floquet\char21{}Born\char21{}马尔可夫方法的基础上精确的数值处理的Floquet哈密顿之间的数值等价性。结果表明，无论是分析计算还是数值计算，我们的方法都比Floquet\char21 {}Born\char21{}Markov方法简单有效。通过对不同处理方法的一般比较，我们论证了驱动耦合和耗散耦合的CR项对相干性和布居差的动力学影响。
We use an analytical method to study the dissipative dynamics of a two-level system (TLS) under a harmonic driving. The method is based on a combination of the unitary transformation and Born\char21{}Markov master-equation approach. Our main aim is to clarify the effects of counter-rotating (CR) terms of both the driving and TLS-bath (dissipative) coupling on the dynamics, in comparison with the rotating-wave results of different schemes, i.e., the well-known traditional rotating-wave approximation method, and two particular methods: one just takes into account the effects of the driving CR terms and the other the effects of the dissipative CR terms, which are derived from our general treatment. Our main results are as follows: (i) by calculating the time-dependent population difference and coherence, in the case of resonant strong driving, we demonstrate that the CR terms of both the driving and dissipative coupling play an important role in the relaxation and dephasing processes, and also the properties of the steady state; (ii) in the case of largely detuned driving, we find that the CR terms of the dissipative coupling become negligible while those of the driving contribute dominant modifications to the time evolution and steady state. Moreover, we examine the influence of the dissipation on coherent destruction of tunneling under a largely detuned strong driving. We show that an almost complete suppression of the tunneling can be achieved for a relatively long time; (iii) under certain conditions, we find numerical equivalence between one of two particular methods and the Floquet\char21{}Born\char21{}Markov approach based on exact numerical treatment of the Floquet Hamiltonian. It turns out that our method is more simple and efficient than the Floquet\char21{}Born\char21{}Markov approach for both analytical and numerical calculations. By the general comparison of different treatments we demonstrate the dynamical effects of CR terms of both the driving and the dissipative coupling on the coherence and population difference.