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Philipp Hanussek

Publications and source records attributed to Philipp Hanussek.

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Quantum-inspired dynamical models on quantum and classical annealers

We propose a practical, physics-inspired benchmarking suite to challenge both quantum and classical computers by mapping real-time quantum dynamics to a common optimization format. Using a parallel-in-time encoding, we convert the real-time propagator of an $n$-qubit, possibly non-Hermitian, Hamiltonian into quadratic unconstrained binary optimization (QUBO) instances that are executable in a solver-agnostic manner on quantum annealers and classical optimizers alike. This enables direct, like-for-like performance comparisons across fundamentally different computational paradigms.To stress-test the framework, we consider eight representative dynamical models spanning single-qubit rotations, multi-qubit entangling gates (Bell, GHZ, cluster), and PT-symmetric and other non-Hermitian generators, and evaluate success probability and time-to-solution as standard benchmarking metrics. Applying this methodology to two generations of D-Wave quantum annealers and to state-of-the-art classical solvers (Simulated Annealing and the GPU-accelerated VeloxQ), we find that Advantage2 consistently outperforms its predecessor, while VeloxQ retains the shortest absolute runtimes, reflecting the maturity of classical heuristics.We further extend the benchmarks to large-scale instances ($N \simeq 10^{5}$), establishing a demanding classical baseline for future hardware. Together, these results position the parallel-in-time QUBO framework as a versatile and physically motivated testbed for quantitatively tracking progress toward quantum-competitive simulation of dynamical systems.

quant-ph

On the oxygen $p$ states in superconducting nickelates

While key attention in transition-metal oxides is usually devoted to the $d$ states of the transition-metal ion, the O$(2p)$ states usually also carry important physics. We here examine these $p$ states in representatives of the novel superconducting nickelates, as described in realistic dynamical mean-field theory. Since the materials are located on the boundary between Mott-Hubbard and charge-transfer systems, the role of oxygen is expectedly subtle. Strong reduction of doped holes on oxygen and first asymmetry effects are featured in infinite-layer nickelates. A pronounced nature of bridging $p_z$ orbitals is identified in the La$_3$Ni$_2$O$_7$ system.

cond-mat.str-el