Quantum Many-Body Dynamics and Noisy Intermediate-Scale Quantum Computers: Interconnections, Near-Term Applications, and Novel Simulation Schemes

Simulating the dynamics of quantum many-body systems is notoriously difficult

as the computational requirements grow dramatically with increasing system

size. While fully-fledged quantum computing may provide a means to handle this

challenge, today's noisy intermediate-scale quantum (NISQ) devices are prone to

errors and decoherence. This interdisciplinary project promises significant

progress in the understanding of nonequilibrium quantum systems and in

leveraging the capabilities of NISQ devices for this purpose. The innovative

research is going to capitalize on the concept of quantum typicality to explore

near-term applications of random quantum states on NISQ devices and to study the

emergence of hydrodynamics in isolated quantum systems. By combining

state-of-the-art theoretical and numerical approaches with simulations on

available quantum hardware, important insights will furthermore be gained into

the universal properties of quantum dynamics in driven-dissipative

systems, in monitored circuits consisting of unitary gates and projective

measurements, and in many-body localized systems coupled to a thermal bath.

Tackling these key areas will provide a deeper understanding of

fundamental physics and will unravel the inevitable interaction of NISQ

devices with their environment. Results may open up new avenues for robust and

scalable simulations on NISQ devices, which is vital as quantum technology

continues to mature. Additionally, this project will deliver novel

NISQ-inspired classical simulation schemes, which are memory-efficient and will

pave the way to answer open questions that are challenging for other methods.

Highlighting the strong synergy and profound interplay between quantum many-body

dynamics and NISQ devices, this project follows Horizon Europe's strategic

plan of developing key digital and emerging technologies and is in line

with Europe's Quantum Flagship initiative to foster European excellence in quantum technologies.