Revealing the quantum nature of memory in non-Markovian dynamics on IBM Quantum

TL;DR

This paper explores the quantum nature of memory effects in non-Markovian dynamics on IBM Quantum hardware, demonstrating the hardware's capability to verify quantum memory in single-qubit systems and proposing methods for two-qubit cases.

Contribution

It introduces a collision-model approach to simulate non-Markovian dynamics on IBM Quantum and demonstrates how to verify quantum memory effects using current noisy quantum processors.

Findings

Current IBM Quantum hardware can verify quantum memory in single-qubit dynamics.

Two-qubit dynamics pose challenges for direct simulation of quantum memory.

An alternative toy example shows how to witness quantum memory in two-qubit systems.

Abstract

We investigate memory effects in non-Markovian dynamics on superconducting quantum processors provided by IBM Quantum. We use a collision-model approach to implement suitable single- and two-qubit dynamics with a gate-based quantum circuit. Coupling the system of interest to an ancilla allows for a characterization of the process with respect to non-Markovian memory effects in general, as well as concerning the quantumness of that memory. We demonstrate that current noisy quantum hardware is capable of verifying quantum memory in single-qubit dynamics. We then discuss why a generalization of this dynamics to the two-qubit case cannot directly be simulated in a way that allows quantum memory to be observed. Nevertheless, we present an alternative toy example that demonstrates how quantum memory of two-qubit dynamics can be witnessed using current noisy quantum computers.