Validating quantum-classical programming models with tensor network simulations

Abstract

The exploration of hybrid quantum-classical algorithms and programming models on noisy near-term quantum hardware has begun. As hybrid programs scale towards classical intractability, validation and benchmarking are critical to understanding the utility of the hybrid computational model. In this paper, we demonstrate a newly developed quantum circuit simulator based on tensor network theory that enables intermediate-scale verification and validation of hybrid quantum-classical computing frameworks and programming models. We present our tensor-network quantum virtual machine (TNQVM) simulator which stores a multi-qubit wavefunction in a compressed (factorized) form as a matrix product state, thus enabling single-node simulations of larger qubit registers, as compared to brute-force state-vector simulators. Our simulator is designed to be extensible in both the tensor network form and the classical hardware used to run the simulation (multicore, GPU, distributed). The extensibility of the TNQVM simulator with respect to the simulation hardware type is achieved via a pluggable interface for different numerical backends (e.g., ITensor and ExaTENSOR numerical libraries). We demonstrate the utility of our TNQVM quantum circuit simulator through the verification of randomized quantum circuits and the variational quantum eigensolver algorithm, both expressed within the eXtreme-scale ACCelerator (XACC) programming model.

Benchmarking Adaptive Variational Quantum Eigensolvers

“…22, the adopted value in this paper is believed to strike a satisfactory balance between accuracy and circuit depth. The resulting circuits were simulated via the TNQVM (tensor-network quantum virtual machine) 33 XACC simulation backend and employed a noiseless, matrix product state (MPS) wave function decomposition for the quantum circuit with the aid of the ITensor library. 34 XACC provides other simulation backends, as well as physical backends targeting QPUs from IBM and Rigetti.…”

“…For the size of the problems studied in this work, there may not be perceived benefits from choosing TNQVM over other XACC simulation backends like Aer 35 or QPP. 36 TNQVM is expected to be advantageous over other simulation approaches for problems requiring more qubits, 33 but we leave this to future work and do not investigate it here.…”

Open source software in quantum computing

“…XACC has its own open source quantum compiler and supports execution on quantum chips from a wide range of quantum hardware companies as well as their respective simulators. There is also an open source plugin that enables the use of a tensor network quantum virtual machine as a backend [47,48]. Finally, the project XACC VQE provides implementations of quantum chemistry algorithms for XACC [49].…”

XACC: a system-level software infrastructure for heterogeneous quantum–classical computing

“…XACC defines Accelerator implementations for IBM, Rigetti, D-Wave, IonQ, and a number of back-end simulators (TNQVM [22], C++ local IBM noise-aware simulator, etc). Each of these physical QPU implementations actually subclass a RemoteAccelerator class, which further subclass Accelerator.…”