Ultrafast vibrational spectroscopy and relaxation in polyatomic molecules: Potential for molecular parallel computing

Torres, Elva A.; Kompa, K. L.; Remacle, Françoise; Levine, R. D.

doi:10.1016/j.chemphys.2008.01.015

Cited by 10 publications

(5 citation statements)

References 19 publications

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“…The operation is inherently parallel (15). A simple situation is when a molecule relaxes after being perturbed by an optical (16,17) or an electrical pulse (18,19). In optical molecular implementations, several states can be simultaneously addressed, which leads to massively parallel linear finitestate machines (16,17).…”

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confidence: 99%

Molecular decision trees realized by ultrafast electronic spectroscopy

Fresch

Hiluf

Collini

et al. 2013

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

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The outcome of a light-matter interaction depends on both the state of matter and the state of light. It is thus a natural setting for implementing bilinear classical logic. A description of the state of a time-varying system requires measuring an (ideally complete) set of time-dependent observables. Typically, this is prohibitive, but in weak-field spectroscopy we can move toward this goal because only a finite number of levels are accessible. Recent progress in nonlinear spectroscopies means that nontrivial measurements can be implemented and thereby give rise to interesting logic schemes where the outputs are functions of the observables. Lie algebra offers a natural tool for generating the outcome of the bilinear light-matter interaction. We show how to synthesize these ideas by explicitly discussing three-photon spectroscopy of a bichromophoric molecule for which there are four accessible states. Switching logic would use the on-off occupancies of these four states as outcomes. Here, we explore the use of all 16 observables that define the timeevolving state of the bichromophoric system. The bilinear lasersystem interaction with the three pulses of the setup of a 2D photon echo spectroscopy experiment can be used to generate a rich parallel logic that corresponds to the implementation of a molecular decision tree. Our simulations allow relaxation by weak coupling to the environment, which adds to the complexity of the logic operations.finite-state machines | Shannon decomposition | parallel multivalued logic | quaternary logic T he need to further reduce the physical dimensions of a computing node is well recognized (1-4). A direct way to go below a nanometer scale is to use a molecule or an artificial atom-a quantum dot-as a switch (5-11). Molecules can also respond in more interesting ways than switching. So for some time we have followed a program of seeking to implement an entire logic circuit on an atom or molecule and to concatenating such units. To do so, we used intramolecular dynamics resulting from the response of a molecule to a perturbation-the inputs to the computationthat can be electrical (12) or optical (13) or chemical (14), etc. In principle, such an approach can implement finite-state logic (15) because typically the response of a molecule depends on its initial state as well as on the applied perturbation.In finite-state machines, the execution of the logic relies on transitions between states. The operation is inherently parallel (15). A simple situation is when a molecule relaxes after being perturbed by an optical (16,17) or an electrical pulse (18,19). In optical molecular implementations, several states can be simultaneously addressed, which leads to massively parallel linear finitestate machines (16,17). The other mode of operation is to provide inputs at each machine cycle. If the molecule is switched between two states, the ability to encode a dependence on the initial state means that one can implement memristor logic (20). More elaborated memory integrated units like set-reset ...

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confidence: 99%

Molecular decision trees realized by ultrafast electronic spectroscopy

Fresch

Hiluf

Collini

et al. 2013

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

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“…Such processes can be treated by including the nuclear spin properties in the description of the system. Electromagnetic fields also play an important role in molecular relaxation processes [46,47]. Therefore, it will also be interesting to include the electromagnetic fields in the quantum description of the system.…”

Section: Discussionmentioning

confidence: 99%

Quantum molecular master equations

et al. 2016

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We present the quantum master equations for midsize molecules in the presence of an external magnetic field. The Hamiltonian describing the dynamics of a molecule accounts for the molecular deformation and orientation properties, as well as for the electronic properties. In order to establish the master equations governing the relaxation of free-standing molecules, we have to split the molecule into two weakly interacting parts, a bath and a bathed system. The adequate choice of these systems depends on the specific physical system under consideration. Here we consider a first system consisting of the molecular deformation and orientation properties and the electronic spin properties and a second system composed of the remaining electronic spatial properties. If the characteristic time scale associated with the second system is small with respect to that of the first, the second may be considered as a bath for the first. Assuming that both systems are weakly coupled and initially weakly correlated, we obtain the corresponding master equations. They describe notably the relaxation of magnetic properties of midsize molecules, where the change of the statistical properties of the electronic orbitals is expected to be slow with respect to the evolution time scale of the bathed system.

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“…This signal is usually binned into few ranges, often just two, sometimes three or four. Multilevel logic, 5 , 8 – 12 which is more compact, is enabled by discretizing into more than two bins. However, there is an inherent loss of information in binning continuous variables.…”

Section: Introductionmentioning

confidence: 99%