Gupta, Eesh: Error Mitigating Quantum Computations of Molecular Ground States

Title: Error Mitigating Quantum Computations of Molecular Ground States

Name: Stephen Schnetzer and Rikab Gambhir

Major: Computer Science; Physics

School affiliation: School of Arts and Sciences

Programs: Aresty Summer Science Program

Other contributors: Stephen Schnetzer and Rikab Gambhir

Abstract: Some of the most promising near-term applications of quantum computers lie in solving classically intractable problems in chemistry, leading to potential breakthroughs in disease prevention. However, quantum computers of today are both highly susceptible to errors and limited by the number of qubits to correct them. For the near term, scientists are exploring error mitigation techniques to reduce the effects of quantum computational noise. One such popular technique is Richardson extrapolation which approximates the ‘zero error’ solution by deliberately increasing the noise in the device. Driven to do better, we compare the Richardson extrapolation method with a much simpler method of polynomial fitting to calculate the ground state energy of the hydrogen molecule. To test these methods, we perform experiments on quantum computers available through IBM cloud. Our results show that polynomial fitting far outperforms the Richardson technique in terms of both precision and accuracy. These schemes, however, are not sufficient for obtaining the needed chemical accuracy. Thus, we hope to explore other error mitigation techniques to further improve quantum computations and advance this promising field.