title: Molecular decision trees realized by ultrafast electronic spectroscopy.
abstract: 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 time-evolving state of the bichromophoric system. The bilinear laser-system 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.
authors.affiliation: Department of Chemistry, University of Liège, B4000 Liège, Belgium.
authors.forename: Barbara
authors.initials: B
authors.lastname: Fresch
authors.forename: Dawit
authors.initials: D
authors.lastname: Hiluf
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Collini
authors.forename: R D
authors.initials: RD
authors.lastname: Levine
authors.forename: F
authors.initials: F
authors.lastname: Remacle
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D003663:Decision Trees; D008962:Models, Theoretical; D017785:Photons; D013057:Spectrum Analysis / Q000379:methods*
keywords: Shannon decomposition; finite-state machines; parallel multivalued logic; quaternary logic
references.citation: Chemphyschem. 2013 Jan 14;14(1):28-46
references.pmid: 22689469
references.citation: Proc Natl Acad Sci U S A. 2012 Dec 26;109(52):21228-33
references.pmid: 23236131
references.citation: Chemphyschem. 2002 Jan 18;3(1):43-51
references.pmid: 12465475
references.citation: Sci Am. 2000 Jun;282(6):86-93
references.pmid: 10862428
references.citation: Nat Nanotechnol. 2012 Feb 19;7(4):242-6
references.pmid: 22343383
references.citation: Science. 2011 Sep 23;333(6050):1723-6
references.pmid: 21835982
references.citation: Chem Phys. 2007 Nov 15;341(1-3):29-36
references.pmid: 19011677
references.citation: Nat Nanotechnol. 2007 Jul;2(7):399-410
references.pmid: 18654323
references.citation: J Chem Phys. 2006 Jan 14;124(2):024106
references.pmid: 16422570
references.citation: Chem Soc Rev. 2013 Jun 21;42(12):4932-47
references.pmid: 23417162
references.citation: Nature. 2003 Oct 16;425(6959):698-701
references.pmid: 14562098
references.citation: Proc Natl Acad Sci U S A. 2005 Apr 19;102(16):5653-8
references.pmid: 15821028
references.citation: Nature. 2008 May 1;453(7191):80-3
references.pmid: 18451858
references.citation: Science. 2009 Jan 16;323(5912):369-73
references.pmid: 19150843
references.citation: Science. 2013 Apr 5;340(6128):52-6
references.pmid: 23559244
references.citation: Chem Rev. 2008 Sep;108(9):3481-548
references.pmid: 18582117
references.citation: Nat Commun. 2013;4:1390
references.pmid: 23340430
references.citation: J Chem Phys. 2005 Sep 15;123(11):114506
references.pmid: 16392572
references.citation: Acc Chem Res. 2011 Aug 16;44(8):563-73
references.pmid: 21678901
references.citation: Chem Commun (Camb). 2006 May 28;(20):2147-9
references.pmid: 16703136
references.citation: Proc Natl Acad Sci U S A. 2011 Aug 23;108(34):13969-72
references.pmid: 21808050
references.citation: Acc Chem Res. 2009 Sep 15;42(9):1352-63
references.pmid: 19691358
references.citation: J Chem Phys. 2006 Jun 21;124(23):234505
references.pmid: 16821927
references.citation: Chemistry. 2009;15(6):1310-3
references.pmid: 19115289
references.citation: Phys Chem Chem Phys. 2012 Mar 21;14(11):3725-36
references.pmid: 22327638