Coherent exciton dynamics in a dissipative environment maintained by an off-resonant vibrational mode

Abstract

The interplay between an open quantum system and its environment can lead to both coherent and incoherent behavior. We explore the extent to which strong coupling to a single bosonic mode can alter the coherence properties of a two-level system in a structured environment. This mode is treated exactly, with the rest of the environment comprising a Markovian bath of bosonic modes. The strength of the coupling between the two-level system and the single mode is varied for a variety of forms for the bath spectral density in order to assess whether the coherent dynamics of the two-level system are modified. We find a clear renormalization of the site population oscillation frequency that causes an altered interaction with the bath. This leads to enhanced or reduced coherent behavior of the two-level system, depending on the form of the spectral density function. We present an intuitive interpretation, based on an analytical model, to explain the behavior.

Measurements of nanoresonator-qubit interactions in a hybrid quantum electromechanical system

“…A second (and related) direction is the use of the nanoresonator as an engineered reservoir to which the transmon could be controllably coupled for exploring the influence of specially tailored thermal and nonthermal baths. Structured baths that differ from the standard Ohmic form and hence display non-Markovian behavior are currently a subject of considerable theoretical interest, particularly when the environment contains some number of strongly coupled discrete modes [49,50,51,52,53,54]. Recent experiments have demonstrated the feasibility of characterizing and even actively engineering such non-Markovian environments in optomechanical [55] and circuit QED systems [56].…”

Hierarchical-environment-assisted non-Markovian and its effect on thermodynamic properties

“…These measures have been applied to many models to investigate their non-Markovian characteristics [17][18][19][20][21][22][23][24]. Furthermore, the transition from Markovian to non-Markovian dynamics has also been theoretically and experimentally implemented based on these measures [25][26][27][28][29][30][31]. For example, Brito et al have implemented the transitions from Markovianity to non-Markovianity by preparing different system initial states or dynamically manipulating the subsystem coupling [26].…”

Coherent dynamics of a qubit-oscillator system in a noisy environment

“…Due to the fact that the coupling with the surrounding bath is unavoidable, how to fight against the decoherence becomes a very important research field. Various strategies have been proposed to reduce the decoherence in a quantum dissipative system, for example, applying a train of decoupling pulses [12][13][14][15], introducing non-linear coupling between the qubit system and its surrounding bath [16][17][18][19][20][21], and adding an auxiliary degree of freedom to change the effective bath density spectral function which is responsible for the decoherence behavior [22,23]. Each scheme has its own regimes of validity depending on the qubit-bath coupling strength, temperature of the bath, as well as the bath density spectral function.…”

“…In this paper, motivated by Refs. [22,23], we try to achieve a tunable coherent dynamics of a biased qubit-bath model by introducing an auxiliary single-mode harmonic oscillator which acts as a controllable degree of freedom. A similar qubit-oscillator-bath system is also studied in Ref.…”

“…We also want to emphasize that our study is a nontrivial extension of Refs. [22,23] in the following two aspects: first, we consider the nonzero bias effect and use a different bath density spectral function. Second, we adopt the hierarchical equations of motion (HEOM) approach [17,26,27] rather than a perturbative theory to investigate the coherent dynamics of the qubit-oscillator-bath system.…”