Princeton University

School of Engineering & Applied Science

Condensed matter physics with near-term quantum computers

Dr. Sonika Johri, Quantum Computing Group, Intel Corporation
Engineering Quadrangle, B205
Tuesday, December 5, 2017 - 11:00am

Few-qubit digital quantum computers are rapidly becoming a reality [1]. Their first applications will be the study of correlated quantum systems. For this, developing the quantum computing equivalent of the techniques that extract information from classical numerical simulation is of vital importance. Along these lines, we will outline a quantum algorithm to efficiently compute the entanglement spectrum of arbitrary quantum states using the lower Renyi entropies [2]. We will then present the experimental validation of this algorithm by calculating the second Renyi entropy of the ground state of the two-site Fermi-Hubbard model on a 5-qubit programmable quantum computer based on trapped ions. We will show that despite error-prone individual qubit gate operations, we are able to improve the overall accuracy of the measured Renyi entropy by over 40% using a symmetry-based post-selection scheme. Finally, we will discuss future applications for systems of 10 - 50 qubits ranging from the study of many-body topological states to the time-evolution of high-energy states of disordered systems.

[2] Sonika Johri, Damian S Steiger and Matthias Troyer, Physical Review B 96,195136 (2017).