Demonstration of Quantum Capability in Ground-State and XAFS Simulations on Real Quantum Devices

We present a quantum computational framework executed on real quantum hardware for efficient evaluation of ground states and X-ray absorption fine structure (XAFS) spectra. The ground-state determination is achieved using the Probabilistic Imaginary Time Evolution (PITE) method, which systematically projects a trial wavefunction onto the ground state while maintaining resource efficiency on fault-tolerant quantum architectures. Once the ground state is obtained, we employ a Quantum Phase Estimation (QPE)-based sampling approach to compute XAFS spectra directly from the quantum state. This algorithm enables efficient extraction of spectral features without explicit diagonalization, offering a scalable pathway to treat strongly correlated systems. The combined use of PITE and QPE-based sampling demonstrates two complementary aspects of quantum computation: accurate ground-state preparation and direct spectral analysis. Implementing this framework on actual quantum hardware showcases the current capability and potential of quantum devices for practical materials simulations. Our results indicate that this integrated approach can accelerate quantum simulations beyond classical limitations, paving the way toward achieving quantum advantage in condensed matter and materials science applications.