Quantum many-body simulations on digital quantum computers: State-of-the-art and future challenges

by Benedikt Fauseweh

Thursday Dec 5, 2024, 2:15 PM → 3:45 PM Europe/Berlin

D5-153 (UHG)

Understanding and simulating many-body quantum systems is an inherently challenging task. In
1981, Richard Feynman proposed that quantum systems could be effectively simulated by a
computer that follows the same principles as quantum mechanics. The idea of a quantum
computer was born. While many other applications for quantum computers have been
discovered since then, Feynman’s original idea, now called Digital Quantum Simulation (DQS),
has evolved from analog methods to advanced digital platforms, driven by significant
experimental progress, e.g., using ultracold atoms or trapped ions.
In this talk, I will provide an overview of the progression of DQS, from its initial concept to
current implementations [1]. Modern noisy quantum computers present challenges due to the
non-error-corrected nature of these systems. To navigate this landscape, novel quantum
algorithms, e.g. hybrid classical-quantum algorithms [2], have been developed to fit the
specifications of such devices. For DQS, the prevailing question today is: What problems are
amenable to be simulated on noisy quantum computers? I will discuss recent work on
simulating quantum many-body dynamics [3], algorithmic advances to detect ground state
phase transitions [4] and the potential of stabilizing exotic non-equilibrium phases of matter,
e.g., discrete time crystals, using quantum-classical feedback [5].

[1] B. Fauseweh, “Quantum many-body simulations on digital quantum computers: State-of-the-
art and future challenges”, Nat. Comm., 15, 2123, (2024)
[2] B. Fauseweh and J.-X. Zhu, “Quantum computing Floquet energy spectra,” Quantum 7,
1063, (2023)
[3] B. Fauseweh and J.-X. Zhu, “Digital Quantum Simulation of Non-Equilibrium Quantum Many-
Body Systems,” Quantum Inf. Process., 20, 138, (2021)
[4] K. Lively, T. Bode, J. Szangolies, J.-X. Zhu, B. Fauseweh, “Noise-Robust Detection of
Quantum Phase Transitions,” arXiv:2402.18953 (2024)
[5] G. Camacho, B. Fauseweh, “Prolonging a discrete time crystal by quantum-classical
feedback”, Phys. Rev. Research 6, 033092 (2024)