James K. Freericks, Georgetown University, (Principal Investigator)
Alexander Kemper, North Carolina State University, (Co-Investigator)
We are on the cusp of entering the world of quantum computing for applications to science. While quantum computers have already existed for a few years, the current hardware is far from ideal---they do not have many qubits, the results are prone to errors, and they cannot run computer codes that are very long. The objective of our work is to find the best applications for cutting-edge science that can be studied on current and near-term quantum computers, and then design and run these algorithms in the most robust fashion with respect to potential errors.
We focus on three main scientific goals for doing this: (i) describing the behavior of driven-dissipative quantum systems; (ii) creating low-energy states of frustrated quantum magnets; and (iii) generating highly entangled spin states that can be employed for improved measurements. In the first problem, we will create quantum systems in artificial electric fields that will drive current through them, but will have energy removed from them at a fixed rate. They will usually end up in a complex quantum steady state, which we will explore with the quantum computer. In the second problem, we will examine a range of different strategies to create low-energy states, of magnets that are frustrated, in the sense that they cannot point their north and south poles where they would like to, to make the lowest-energy arrangement. These systems are some of the most fascinating, but most difficult to study systems in the quantum world. We will devise quantum algorithms to explore their properties. In the third problem, we will create highly entangled states which have at their core, the “spookiness” of quantum mechanics. They are difficult to make and fragile, but we will employ techniques that protect them from being destroyed as we work on making them. Once we are successful, these states can be further used for ultraprecise measurements.
Our approach is a combined classical-quantum computer hybrid approach, which uses the quantum computers primarily to calculate the strongest quantum effects, which are then post-processed by a classical computer to determine the final results. Our methodology is to develop robust algorithms that are resistant to errors and noise, and have a higher chance for successful operation with currently available quantum computers. We have collaborations with IBM, Intel, and the University of Maryland to ensure the ability to run these codes on real quantum hardware. We will also employ quantum computer simulators to ensure our codes are resistant to noise effects and have a high chance to run successfully on currently available quantum hardware.
The impact of this project will be to set the stage for ushering in the era of quantum-computer-assisted scientific discovery. As quantum computers become more robust, we will be able to use them to tackle problems that will lead to exciting new applications of science that have an energy focus and are beneficial to society.
