Stochastic surrogate Hamiltonian

Katz, Gil; Gelman, David; Ratner, Mark A.; Kosloff, Ronnie

doi:10.1063/1.2946703

Cited by 45 publications

(59 citation statements)

References 35 publications

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“…Longer propagation times than those computationally affordable with exact dynamics of system and environment become possible by separating the environment into two baths, one that is responsible for the memory effects and that is modeled by effective modes as explained above, and a second one that by itself would lead to Markovian dynamics only. The secondary bath can be accounted for in terms of a Markovian master equation in Lindblad form [38,70] or via a stochastic unravelling using a single secondary bath mode [71]. A more comprehensive overview over methods to tackle non-Markovian dynamics is found in Ref.…”

Section: A Markovian Vs Non-markovian Dynamicsmentioning

confidence: 99%

Controlling open quantum systems: tools, achievements, and limitations

Koch

2016

J. Phys.: Condens. Matter

243

222

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The advent of quantum devices, which exploit the two essential elements of quantum physics, coherence and entanglement, has sparked renewed interest in the control of open quantum systems. Successful implementations face the challenge to preserve the relevant nonclassical features at the level of device operation. A major obstacle is decoherence which is caused by interaction with the environment. Optimal control theory is a tool that can be used to identify control strategies in the presence of decoherence. We review here recent advances in optimal control methodology that allow for tackling typical tasks in device operation for open quantum systems and discuss examples of relaxation-optimized dynamics. Optimal control theory is also a useful tool to exploit the environment for control. We discuss examples and point out possible future extensions.

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Section: A Markovian Vs Non-markovian Dynamicsmentioning

confidence: 99%

Controlling open quantum systems: tools, achievements, and limitations

Koch

2016

J. Phys.: Condens. Matter

243

222

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“…However, challenges in understanding electronic decoherence have arisen from recent spectroscopic observations that have demonstrated that in some photosynthetic systems electronic coherences can be longlived [13][14][15], with lifetimes exceeding 400-600 fs. These results have lead to discussions of the role of quantum coherences in biological processes and reconsideration of our understanding of decoherence dynamics in single molecules and molecular aggregates [3,[13][14][15][16][17][18][19][20][21][22][23][24]. Many of the associated computations utilize phenomenological models or master equations [25] that approximate the dynamical effects of the bath on the system coordinates without explicitly following the bath dynamics.…”

Section: Introductionmentioning

confidence: 99%

Electronic coherence dynamics in trans-polyacetylene oligomers

Franco

Brumer

2012

The Journal of Chemical Physics

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Electronic coherence dynamics in trans-polyacetylene oligomers are considered by explicitly computing the time dependent molecular polarization from the coupled dynamics of electronic and vibrational degrees of freedom in a mean-field mixed quantum-classical approximation. The oligomers are described by the Su-Schrieffer-Heeger Hamiltonian and the effect of decoherence is incorporated by propagating an ensemble of quantum-classical trajectories with initial conditions obtained by sampling the Wigner distribution of the nuclear degrees of freedom. The electronic coherence of superpositions between the ground and excited and between pairs of excited states is examined for chains of different length, and the dynamics is discussed in terms of the nuclear overlap function that appears in the off-diagonal elements of the electronic reduced density matrix. For long oligomers the loss of coherence occurs in tens of femtoseconds. This timescale is determined by the decay of population into other electronic states through vibronic interactions, and is relatively insensitive to the type and class of superposition considered. By contrast, for smaller oligomers the decoherence timescale depends strongly on the initially selected superposition, with superpositions that can decay as fast as 50 fs and as slow as 250 fs. The long-lived superpositions are such that little population is transferred to other electronic states and for which the vibronic dynamics is relatively harmonic.

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“…As demonstrated earlier (18), this dynamic disorder helps the hole density to overcome the potential barrier created by the electrostatic interactions between the propagating positive charge and the anion S − a . To simulate the dissipative dynamics of the propagating hole, a stochastic surrogate Hamiltonian (SSH) scheme was used (47,(51)(52)(53)(54). The SSH approach is based on the numerical propagation of a multiparticle density matrix that accounts for the degrees of freedom associated with the propagating charge and a few phonon modes (47) (details are provided in SI Text).…”

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confidence: 99%

Impact of a single base pair substitution on the charge transfer rate along short DNA hairpins

Renaud

Berlin

Ratner

2013

Proc. Natl. Acad. Sci. U.S.A.

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Numerical studies of hole migration along short DNA hairpins were performed with a particular emphasis on the variations of the rate and quantum yield of the charge separation process with the location of a single guanine:cytosine (G:C) base pair. Our calculations show that the hole arrival rate increases as the position of the guanine:cytosine base pair shifts from the beginning to the end of the sequence. Although these results are in agreement with recent experimental findings, the mechanism governing the charge migration along these sequences is revisited here. Instead of the phenomenological two-step hopping mechanism via the guanine base, the charge propagation occurs through a delocalization of the hole density along the base pair stack. Furthermore, the variations of the charge transfer with the position of the guanine base are explained by the impact of the base pair substitutions on the delocalized conduction channels.quantum filling | photoinduced hole transfer | stochastic surrogate Hamiltonian D espite a rather long history, investigations of excess charge carriers in DNA remain an area of intensive experimental and theoretical research (reviewed in refs. 1-3). This interest is mainly due to the relevance of the charge transfer (CT) phenomenon to the oxidation damage (4, 5) and to the potential application of DNA in nanoelectronics (6, 7). Experimentally, charge migration through DNA can be probed either by steady-state methods based on measurements of the damage ratio (8-10) or by time-resolved spectroscopic techniques (11)(12)(13)(14). The latter experimental approach was shown to be particularly efficient for monitoring charge motion in DNA hairpins (13). To carry out time-resolved spectroscopic experiments on these small DNA model systems, the opposite ends of the hairpin are capped with stilbene linkers S a and S b , serving as the hole donor and acceptor, respectively. It has been demonstrated that photoexcitation of S a results in the formation of a bound electron-hole pair initially localized on the hole donor. The separation of this pair occurs via the migration of the hole along the hairpin and the subsequent reaction of the positive charge with the stilbene acceptor. Kinetics of the hole arrival at S b , monitored by a second pulse, enable one to deduce the hole arrival rate, k a , and the quantum yield, Φ a , of the charge separation process.Hole migration along hairpins with less than three base pairs is discussed in terms of a single-step superexchange (15-18). In contrast, multistep sequential hopping is assumed to be responsible for charge propagation along longer hairpins (19-23). The competition between these two mechanisms leads to a distance dependence of the hole arrival rate given by:where N is the number of base pairs in the sequence, κ 1 and κ 2 are scaling factors, R 0 = 3:4 A is the mean interbase pair distance, β = 0:5 − 1:0 A −1 is the exponential falloff parameter for the superexchange mechanism (24-29), and η = 1:5 − 2:0 is the exponent of the power law characteristic f...

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Stochastic surrogate Hamiltonian

Cited by 45 publications

References 35 publications

Controlling open quantum systems: tools, achievements, and limitations

Controlling open quantum systems: tools, achievements, and limitations

Electronic coherence dynamics in trans-polyacetylene oligomers

Impact of a single base pair substitution on the charge transfer rate along short DNA hairpins

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