May 31, 2018

Simulating the vibrational quantum dynamics of molecules with photonics

  • Carolan J.
  • Harrold C.
  • Hashimoto T.
  • Joglekar Y.
  • Laing A.
  • Maraviglia N.
  • Martin-Lopez E.
  • Matsuda N.
  • Neville A.
  • O'Brien J.
  • Sparrow C.
  • Tew D.

Advances in control techniques for vibrational quantum states in molecules present new challenges for modelling such systems that could be amenable to quantum simulation methods. Exploiting a natural mapping to photons in waveguides, we demonstrate a reprogrammable photonic chip as a versatile simulation platform for a range of quantum dynamical behaviour in different molecules. We begin by simulating the time evolution of vibrational excitations in the harmonic approximation for a variety of 4-atom molecules, including $mathrm{H_{2}CS, , SO_{3}, , HNCO, , HFHF, , N_{4},}$ and $mathrm{P_{4}}$. We go on to simulate coherent and dephased energy transport in the simplest model of the peptide bond in proteins, N-methylacetamide, and simulate thermal relaxation and the effect of anharmonicities in $mathrm{H_{2}O}$. Finally, we use multi-photon statistics with a feedback control algorithm to iteratively identify quantum states that increase a particular dissociation pathway of $mathrm{NH_{3}}$. These methods point to powerful new simulation tools for molecular quantum dynamics and the field of femtochemistry.

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