ICHEC leads international supercomputing project
QuantEx, which stands for Efficient Quantum Circuit Simulation on Exascale Systems, is a novel quantum simulation project conducted in collaboration with partners at the Leibniz Supercomputing centre (LRZ) and with funding from the Partnership for Advanced Computing in Europe (PRACE).
The project began in January 2020 as part of a PRACE programme designed to develop software solutions that address challenges posed by the rapidly changing HPC pre-Exascale landscape.
QuantEX will require the computing power of SuperMUC-NG, which is currently the fastest supercomputer in the EU. It will also use the supercomputing capabilities of the three large pre-exascale machines that will be installed in Barcelona (BSC), Finland (CSC) and Italy (CINECA) over the next year.
These supercomputers will be used to test and optimise the tools and algorithms developed by the QuantEx team. Results of the simulations are expected by the end of 2021.
Quantum computers make use of fundamental quantum mechanical effects like superposition and entanglement, which are extremely short-lived and difficult to control for macroscopic systems made up of many qubits.
Dr Luigi Lapachino, high performance systems expert at Leibniz Supercomputing Centre, Bavaria said: “The aim of QuantEx is to develop tools for the simulation of quantum circuits.”
Combining qubits and being capable of coherent control can result in exponentially increasing compute power. “This increases the computing and memory requirements as well, if we want to simulate quantum states of an increasing number of qubits,” said Dr Lapichino.
Optimise use of storage
Quantum technology is just emerging from its infancy. Whereas experiments were previously limited to systems with only a handful of qubits, the first Noisy Intermediate Scale Quantum Systems (NISQ) which feature upwards of 50 qubits are now emerging. Even the world’s largest supercomputers really struggle to fit the quantum states required to simulate such systems in memory.
QuantEx aims to develop tools that require less compute and storage capacity but can still simulate the operation of NISQ devices. Tensor network contractions, mathematical methods developed by quantum information theorists and condensed matter physicists for evaluating systems of interacting particles, help here. SuperMUC-NG can store in memory the full quantum state of a system with 42 qubits but with the same memory could simulate up to about 100 qubits for certain circuits thanks to tensor contraction networks.
“Quantum computers are considered promising, powerful potential alternatives to traditional supercomputers,” added Dr Lapachino. “They are not yet mature enough to produce meaningful scientific results, but while waiting for hardware improvements, simulations help.”
“While actual quantum computing is still some way off, the simulation tools we are creating will advance the necessary concepts and skill-sets for quantum programming,” said Dr Niall Moran, principal investigator and project leader of the PRACE WP8 QuantEx project at ICHEC. “This work is being conducted with world-class research teams across a number of Irish third-level institutions and will contribute to preparing Ireland for quantum programming.”
The ICHEC delivers complex compute solutions to Irish HEAs, enterprises and the public sector on behalf of the state.