Observation of discrete time crystals on a quantum computer: Demonstrating quantum utility in a 133-qubit two-dimensional system

Using the 133-qubit IBM Quantum Heron processor "ibm_torino," the team implemented a periodically driven two-dimensional kicked Ising model via digital quantum simulation and demonstrated stable subharmonic oscillations characteristic of discrete time crystals for up to 100 driving cycles. These results were validated through comparison with classical simulations based on the two-dimensional tensor network method performed on the RIKEN supercomputer Fugaku.

This work provides an important experimental benchmark demonstrating that quantum computers can probe the non-equilibrium dynamics of quantum many-body systems in regimes that approach or exceed the limits of classical computational methods.

Quantum many-body systems driven out of equilibrium can exhibit novel phases that do not exist in equilibrium conditions. One prominent example is the discrete time crystal, in which physical observables oscillate at integer multiples of the driving period, breaking the discrete time-translation symmetry imposed by periodic driving.

The experimental results quantitatively agree with classical simulations based on the two-dimensional tensor network method up to approximately 50 cycles, establishing the reliability of the quantum hardware observations. Beyond this time scale, classical simulation becomes increasingly difficult due to rapid entanglement growth, while the quantum processor was able to experimentally explore this regime.

This work demonstrates the growing role of quantum computers as tools for scientific discovery, complementing classical high-performance computing systems such as Fugaku and enabling new approaches to studying complex quantum systems.

This work was supported by the following programs and organizations: