Publications

Open quantum system approaches are widely used in the description of physical, chemical and biological systems. A famous example is electronic excitation transfer in the initial stage of photosynthesis, where harvested energy is transferred with remarkably high efficiency to a reaction center. This transport is affected by the motion of a structured vibrational environment, which makes simulations on a classical computer very demanding. Here we propose an analog quantum simulator of complex open system dynamics with a precisely engineered quantum environment. Our setup is based on superconducting circuits, a well established technology. As an example, we demonstrate that it is feasible to simulate exciton transport in the Fenna-Matthews-Olson photosynthetic complex. Our approach allows for a controllable single-molecule simulation and the investigation of energy transfer pathways as well as non-Markovian noise-correlation effects.

The components of the third-order nonlinear optical susceptibility x^(3) for the 1002-cm^?1 mode of neat benzenethiol have been measured using coherent anti-Stokes Raman scattering with continuous-wave diode pump and Stokes lasers at 785.0 and 852.0 nm, respectively. Values of 2.8±0.3 X 10^-12, 2.0±0.2 X 10^-12, and 0.8±0.1 X 10^-12 cmg^-1 s^2 were measured for the xxxx, xxyy, and xyyx components of |3x^(3)|, respectively. We have calculated these quantities using a microscopic model, reproducing the same qualitative trend. The Raman cross-section sigma RS for the 1002-cm^-1 mode of neat benzenethiol has been determined to be 3.1±0.6 X 10^-29 cm^2 per molecule. The polarization of the anti-Stokes Raman scattering was found to be parallel to that of the pump laser, which implies negligible depolarization. The Raman linewidth (full-width at half-maximum) Gamma was determined to be 2.4±0.3 cm^-1 using normal Stokes Raman scattering. The measured values of sigma RS and Gamma yield a value of 2.1±0.4 X 10^-12 cmg^-1 s^2 for the resonant component of 3x^(3). A value of 1.9±0.9 X 10^-12 cmg^-1 s^2 has been deduced for the nonresonant component of 3x^(3).