Alexander Eisfeld

Towards Outperforming Classical Algorithms with Analog Quantum Simulators

  1. Sarah Mostame,
  2. Joonsuk Huh,
  3. Christoph Kreisbeck,
  4. Andrew J. Kerman,
  5. Takatoshi Fujita,
  6. Alexander Eisfeld,
  7. and Alán Aspuru-Guzik
With quantum computers being out of reach for now, quantum simulators are the alternative devices for efficient and more exact simulation of problems that are challenging on conventional
computers. Quantum simulators are classified into analog and digital, with the possibility of constructing „hybrid“ simulators by combining both techniques. In this paper, we focus on analog quantum simulators of open quantum systems and address the limit that they can beat classical computers. In particular, as an example, we discuss simulation of the chlorosome light-harvesting antenna from green sulfur bacteria with over 250 phonon modes coupled to each electronic state. Furthermore, we propose physical setups that can be used to reproduce the quantum dynamics of a standard and multiple-mode Holstein model. The proposed scheme is based on currently available technology of superconducting circuits consist of flux qubits and quantum oscillators.
arxiv pdf

Quantum simulator of an open quantum system using superconducting qubits: exciton transport in photosynthetic complexes

  1. Sarah Mostame,
  2. Patrick Rebentrost,
  3. Alexander Eisfeld,
  4. Andrew J. Kerman,
  5. Dimitris I. Tsomokos,
  6. and Alán Aspuru-Guzik
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.
arxiv pdf