Optimal control theory – closing the gap between theory and experiment

Hoff, P. von den; Thallmair, Sebastian; Kowalewski, Markus; Siemering, R.; Vivie‐Riedle, Regina de

doi:10.1039/c2cp41838j

Cited by 71 publications

(90 citation statements)

References 134 publications

(234 reference statements)

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“…However, these values are not good enough to allow fault-tolerant quantum computation, which requires the gate fidelity > 99.9% [27]. One of the strategies to increase the fidelity is to apply more complex coherent control techniques such as optimal control [28] and genetic [29] algorithms to shape laser pulses. Optimal control of STIRAP based blockaded controlled phase gate has been analyzed recently in [20], where it was shown that the gate error can be decreased by an order of magnitude (from 10 −3 to 10 −4 ) if one uses optimized pulse sequences instead of analytic.…”

Section: Controlled Phase Gate Using Arp Excitation To Double Rydmentioning

confidence: 99%

Chirped pulse excitation of two-atom Rydberg states

Kuznetsova¹

2015

J. Phys. B: At. Mol. Opt. Phys.

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We analyze excitation of two ground state atoms to a double Rydberg state by a two-photon chirped optical pulse in the regime of adiabatic rapid passage. For intermediate Rydberg-Rydberg interaction strengths, relevant for atoms separated by ∼ten µm, adiabatic excitation can be achieved at experimentally feasible Rabi frequencies and chirp rates of the pulses, resulting in high transfer efficiencies. We also study the adiabatic transfer between ground and Rydberg states as a means to realize a controlled phase gate between atomic qubits.

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Section: Controlled Phase Gate Using Arp Excitation To Double Rydmentioning

confidence: 99%

Chirped pulse excitation of two-atom Rydberg states

Kuznetsova¹

2015

J. Phys. B: At. Mol. Opt. Phys.

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“…Therefore, several experimental and theoretical studies have since been carried out on diatomic molecules. [25][26][27][28][29] De VivieRiedle extended the concept theoretically to larger molecular systems by studying in reduced dimensionality the effect of the initial conditions on the subsequent dynamics: 30,31 it was suggested to control the relative phases and amplitudes of a superposition of electronic states near a conical intersection to "steer" chemical reactions and control the branching ratio of populations for instance. Using the Ehrenfest method, we have previously investigated the nature of the nuclear motion when an electronic wave packet is populated in benzene and toluene cations: 32,33 we have shown that manipulation of the details of the electronic wave packet (relative weight and phase) leads to the control of the initial nuclear motion.…”

Section: Introductionmentioning

confidence: 99%

Electron and nuclear dynamics following ionisation of modified bismethylene-adamantane

et al. 2016

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We have simulated the coupled electron and nuclear dynamics using the Ehrenfest method upon valence ionisation of modified bismethylene-adamantane (BMA) molecules where there is an electron transfer between two π bonds. We have shown that the nuclear motion significantly affects the electron dynamics after a few fs when the electronic states involved are close in energy. We have also demonstrated how the non-stationary electronic wave packet determines the nuclear motion, more precisely the asymmetric stretching of the two π bonds, illustrating "chargedirected reactivity". Taking into account the nuclear wave packet width results in the dephasing of electron dynamics with a half-life of 8 fs; this eventually leads to the equal delocalisation of the hole density over the two methylene groups and thus symmetric bond lengths.

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“…and is not directly relevant for control. quantum phenomena or quantum optical control could then be adapted [36][37][38][39]. Light-induced C.I., created in molecules with the help of external laser fields, could be used to control the position of the intersection and the strength of the nonadiabatic coupling [40,41].…”

Section: Note That Trðρmentioning

confidence: 99%

Control of Nuclear Dynamics through Conical Intersections and Electronic Coherences

et al. 2018

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The effect of nuclear dynamics and conical intersections on electronic coherences is investigated employing a two-state, two-mode linear vibronic coupling model. Exact quantum dynamical calculations are performed using the multiconfiguration time-dependent Hartree method. It is found that the presence of a nonadiabatic coupling close to the Franck-Condon point can preserve electronic coherence to some extent. Additionally, the possibility of steering the nuclear wave packets by imprinting a relative phase between the electronic states during the photoionization process is discussed. It is found that the steering of nuclear wave packets is possible given that a coherent electronic wave packet embodying the phase difference passes through a conical intersection. A conical intersection close to the Franck-Condon point is thus a necessary prerequisite for control, providing a clear path towards attochemistry. DOI: 10.1103/PhysRevLett.120.123001 Ultrashort laser pulses allow us to resolve electronic and nuclear motion in molecules on their natural time scales [1][2][3][4]. With the dawn of attosecond pulses, it is now possible to create coherent superpositions of excited electronic states of a photoionized molecule. Electronic coherences are believed to be important for a wide range of processes, e.g., electron hole oscillations [5] and efficient energy conversion in light-harvesting complexes [6]. In theoretical descriptions of electronic coherence, the nuclei are often fixed as they are heavy compared to the electrons. Such calculations predict long-lived coherences and electron hole migrations driven by electron correlation [5,[7][8][9]. However, recent quantum-dynamical studies show that the motion of nuclei cannot be neglected and that nuclear motion can lead to electronic decoherence within a few femtoseconds [10][11][12][13][14][15].The interplay of electronic and nuclear motion becomes especially relevant in the presence of strong nonadiabatic couplings, as the Born-Oppenheimer separation breaks down and the time scales of electronic and nuclear motion become comparable [16]. Nonadiabatic couplings are particularly strong at conical intersections (C.I.), which are abundant in the potential energy landscape of polyatomic molecules [17,18]. First insight into the influence of C.I.s on electronic coherence was obtained recently with a quantum-dynamical treatment of paraxylene and BMA [5,5], but a systematic understanding remains elusive [14].Nonadiabatic couplings and C.I.s are already exploited in control schemes employing femtosecond laser pulses. The underlying processes are typically well understood and the nuclear wave packet can be steered to desired reaction products [16,[19][20][21][22]. With attosecond pulses, due to their large width in the energy domain, it becomes feasible to control the electronic rather than the nuclear degrees of freedom. Through nonadiabatic couplings, the relative weight and phase between electronic states may affect the velocity as well as the direction of nuclear dynamics, ...

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Optimal control theory – closing the gap between theory and experiment

Cited by 71 publications

References 134 publications

Chirped pulse excitation of two-atom Rydberg states

Chirped pulse excitation of two-atom Rydberg states

Electron and nuclear dynamics following ionisation of modified bismethylene-adamantane

Control of Nuclear Dynamics through Conical Intersections and Electronic Coherences

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