Quantum Coffee | Journal Club: Effective horizons on a quantum processor: what can a 32-qubit experiment tell us about Hawking radiation and scrambling?

Black holes radiate thermally at a temperature set by their surface gravity, and as quantum systems they are believed to be the fastest scramblers of information in nature.

Neither effect can be observed astrophysically. Analogue simulators offer an alternative: controllable systems whose excitations experience an effective horizon. In this journal club we discuss a recent experiment (Smith et al., arXiv:2608.19318) that simulates a chiral spin chain on IBM superconducting hardware with up to 32 qubits, where such a horizon is created by tuning the couplings in space. We will see with a short calculation how a horizon appears in the dispersion relation of a spin chain, and then focus on the quantum-simulation side: how the circuits are built, how the observables are extracted from noisy hardware, and which parts of the experiment are actually beyond classical simulation.