INSPIRE: Excitonic Quantum Coherence - A Viable Path to Quantum Computing

NONTECHNICAL DESCRIPTION: This is an INSPIRE grant. Universal quantum computers with the ability to solve problems beyond the capability of present supercomputers have yet to be realized. This interdisciplinary project focuses on whether the assembly of organic dye molecules into complex excitonic networks using DNA self-assembly provides a viable path for the construction of such computers. An exciton is the packet of energy that resides in an organic dye molecule when it is in its excited state. This packet of energy is a quantum mechanical object that exhibits both wave-like and particle-like behavior just as light does. A manifestation of the wave-like behavior of the exciton is its ability to spread out over a dye molecule network so that it resides on multiple chromophores simultaneously. This process is referred to as excitonic quantum coherent energy transfer. A manifestation of the particle-like behavior is that two excitons can collide and scatter off of each other as they spread over a dye molecule network. By exploiting these two behaviors, in principle, dye molecules can be arranged into networks that function as quantum gates and quantum computers. In order for quantum coherent energy transfer to occur, dye molecules must be brought within a few nanometers of each other and, in order to build a quantum gate, dye molecules must be found for which quantum coherence can be maintained over a large dye network. The fundamental issue this research is seeking to address is whether dye molecules of sufficient quality can be found and whether these can be arranged into the complex networks with the close spacing required in order to make a functioning quantum gate and thereby provide a path to scalable universal quantum computation. This research program provides Boise State University students specific educating, training and mentoring in nanophotonics and computational materials science. This experience equips these students to meet the ever evolving and advancing technological needs of both local and national high tech industries and educational and scientific institutions. Combining education, training, and research with outreach, this research will advance the discovery, innovation, and overall knowledge-based prosperity of science and engineering.

Technical Description:

The goal of this research is to develop a new materials system for the assembly of quantum computers in which quantum computation is carried out by a many-exciton quantum walk over a network of dye molecules. The two primary tasks of this research are (1) to identify suitable dye molecules and (2) to determine the means by which these dye molecules, when covalently attached to DNA, can be arranged into the requisite configurations to function as quantum gates. In the first task, dye molecules are identified that, when paired using DNA assembly, exhibit large Davydov splitting and strong exciton-exciton interactions as determined by absorption spectroscopy and differential absorption spectroscopy, respectively. In the second task, how best to covalently attach dye molecules to DNA substrates to form quantum coherently interacting dye networks is established. A fundamental issue addressed by this research is how to effectively perform computation with excitons. The work impacts existing quantum computation research by providing new gate architectures that are robust against dispersion and decoherence and that have faster switching times than existing quantum gates.

The grant is co-funded by the following programs, OIA; EPSCoR; CISE; ENG; and MPS.