We implement a chiral spin-chain black hole simulator on IBM superconducting quantum hardware and probe, within a common microscopic framework, both semiclassical horizon physics and interacting quantum scrambling. We first measure the dispersion relation across the exterior, horizon and over-tilted interior regimes, reproducing the predicted evolution of the effective light-cone structure. To probe Hawking thermality, we prepare a localised excitation inside the horizon and monitor its density response at an exterior site, observing the predicted inverse relation between the peak arrival time and the surface gravity, thereby establishing a calibrated dynamical estimator of the Hawking temperature. Beyond the semiclassical regime, we continuously tune the interactions and distinguish non-exponential operator spreading in the free-fermion limit from Lyapunov-like OTOC decay in the strongly interacting chiral regime. These measurements use observable-specific Floquet circuits derived from the same parent chiral model, including its mean-field and coordinate-equivalent XY descriptions, to reduce circuit depth while preserving the physics relevant to each probe. Our results provide a unified programmable platform for studying horizon geometry, Hawking thermality and interacting scrambling on quantum hardware.
We implement a chiral spin-chain black hole simulator on IBM superconducting quantum hardware and probe, within a common microscopic framework, both semiclassical horizon physics and interacting quantum scrambling. We first measure the dispersion relation across the exterior, horizon and over-tilted interior regimes, reproducing the predicted evolution of the effective light-cone structure. To probe Hawking thermality, we prepare a localised excitation inside the horizon and monitor its density response at an exterior site, observing the predicted inverse relation between the peak arrival time and the surface gravity, thereby establishing a calibrated dynamical estimator of the Hawking temperature. Beyond the semiclassical regime, we continuously tune the interactions and distinguish non-exponential operator spreading in the free-fermion limit from Lyapunov-like OTOC decay in the strongly interacting chiral regime. These measurements use observable-specific Floquet circuits derived from the same parent chiral model, including its mean-field and coordinate-equivalent XY descriptions, to reduce circuit depth while preserving the physics relevant to each probe. Our results provide a unified programmable platform for studying horizon geometry, Hawking thermality and interacting scrambling on quantum hardware.
We investigate the apparent thermality of Hawking radiation in the semi-classical limit of quantum black holes using the mean-field limit of a chiral spin-chain simulator, which models fermions propagating on a black hole space-time in the continuum. In this free-theory regime, no genuine thermalisation occurs. Nevertheless, we show that a bipartition across the event horizon yields a reduced density matrix whose mode occupations follow an apparent thermal Fermi-Dirac distribution. In contrast, partitions away from the horizon do not exhibit such thermal distributions, reflecting the absence of thermal behaviour. Our results demonstrate that Hawking radiation appears thermal only with respect to horizon bipartitions in free theories, with genuine thermal behaviour expected to emerge only in the presence of strong interactions deep in the black hole interior, a study of which we leave for future work.
There is currently significant interest in emulating the essential characteristics of black holes, such as their Hawking radiation or their optimal scrambling behavior, using condensed matter models. In this article, we investigate a chiral spin-chain, whose mean field theory effectively captures the behavior of Dirac fermions in the curved spacetime geometry of a black hole. We find that within the region of the chain that describe the interior of the black hole, strong correlations prevail giving rise to many-body chaotic dynamics. Employing out-of-time-order correlations as a diagnostic tool, we numerically compute the associated Lyapunov exponent. Intriguingly, we observe a linear increase in the Lyapunov exponent with temperature within the black hole's interior at low temperatures, indicative of optimal scrambling behavior. This contrasts with the quadratic temperature dependence exhibited by the spin-chain on the region outside the black hole. Our findings contribute to a deeper understanding of the interplay between black hole geometry and quantum chaos, offering insights into fundamental aspects of quantum gravity.
Abstract Hawking radiation, predicted in 1974, establishes a fundamental bridge between quantum mechanics, general relativity, and thermodynamics. Direct observation remains impossible for astrophysical black holes (T_H ~ 10⁻⁸ K), motivating the development of analog systems. We report the first large-scale kinematic analog of Hawking radiation on a superconducting quantum processor, utilizing IBM Quantum Heron (ibm_fez, 156 qubits) with four spin chains deployed across calibration-verified low-noise regions. Our Multi-Horizon Interleaved Layout (MHIL) architecture enables up to four simultaneous 'Hawking universes' with O(1) circuit depth independent of system size, requiring zero SWAP gates through native heavy-hex topology exploitation. We demonstrate: (i) spatial localization of entanglement flux at the analog horizon with ratio F_h/F_far = 83.2× under optimized error mitigation (44.3× under standard reproducible conditions) (threshold: 1.8×); (ii) monotonic temporal dynamics with R² = 0.999; (iii) multi-chain reproducibility across three independent horizons; (iv) rigorous statistical validation showing 91.6% signal degradation under shuffle control (p < 0.001, Cohen's d = 4.7), supporting a physical origin of the observed correlations. IMPORTANT CLARIFICATION: This work demonstrates KINEMATIC (not thermodynamic) analog Hawking radiation. We observe spatial localization and pair correlation signatures consistent with the kinematic aspects of Hawking's prediction. We do NOT measure a thermal Planck spectrum, do NOT extract a Hawking temperature T_H, and do NOT achieve Bell-CHSH violation (S ≈ 0.4 < 2.0). These limitations are explicitly acknowledged. Extensions include the first non-integrable regime simulation (98 qubits, disorder strength W = 0.65) and preliminary exploratory evidence of analog wormhole cross-throat flux (48 qubits, 5/5 seeds validated, p = 0.031—this preliminary result requires confirmation with larger sample size). These results establish the viability of kinematic analog Hawking simulations on NISQ superconducting processors accessible via cloud, opening quantum gravity phenomenology to the broader research community without specialized infrastructure.
Abstract Hawking radiation is one of the quantum features of a black hole that can be understood as a quantum tunneling across the event horizon of the black hole, but it is quite difficult to directly observe the Hawking radiation of an astrophysical black hole. Remarkable experiments of analogue black holes on various platforms have been performed. However, due to the experimental difficulty of accurately constructing curved spacetime and precisely measuring the thermal spectrum, Hawking radiation and its quantum nature, such as entanglement, have not been adequately investigated. Based on the recent architecture breakthrough of tunable couplers for superconducting processors, we experimentally realize an analogue black hole using our newly developed chip with a chain of 10 superconducting transmon qubits with interactions mediated by 9 transmon-type tunable couplers. By developing efficient techniques to engineer the couplings between qubits via tuning couplers, we achieve both flat and curved spacetime backgrounds. The quantum walks of quasi-particle in the curved spacetime reflect the gravitational effect near the black hole, resulting in the behavior of Hawking radiation. By virtue of the state tomography measurement of all 7 qubits outside the analogue event horizon, we show that Hawking radiation can be verified. In addition, an entangled pair is prepared inside the horizon and the dynamics of entanglement in the curved spacetime is directly measured. Our results would stimulate more interests to explore the related features of black holes using the programmable superconducting processor with tunable couplers.
In the curved spacetime of a black hole, quantum physics gives rise to distinctive effects such as Hawking radiation and maximally fast scrambling. Here, we present a scheme for an analogue quantum simulation of (1 + 1) and (2 + 1)-dimensional black holes using ultracold atoms in a locally Floquet-driven optical lattice. We show how the effective dynamics of the driven system can generate position-dependent tunnelling amplitudes that encode the curved geometry of the black hole. Moreover, we provide a simple and robust scheme to determine the Hawking temperature of a (1+1)D simulated black hole based solely on on-site atom population measurements. Combined with the highly tunable onsite atom-atom interactions typical for cold atoms, our simulator provides a powerful and feasible platform to probe the scrambling of quantum information in black holes. We illustrate the ergodicity of our (2+1)D black-hole simulator by showing numerically that its level statistics in the hard-core limit approaches the ergodic regime faster than a globally homogeneous Hamiltonian.
We report the first experimental observation of analog Hawking radiation signatures on a 156-qubit superconducting quantum processor (IBM Heron R2). Using a spatially-varying XY spin chain with engineered coupling profile J(x) = J₀[1 - κ·tanh((x-x_h)/w)], we create an analog event horizon where excitation transport is kinematically forbidden. Our Multi-Horizon Interleaved Layout (MHIL) architecture enables up to four simultaneous "Hawking universes" with O(1) circuit depth scaling, achieving 156-qubit operation in only 44 transpiled layers. We demonstrate: (i) spatial localization of entanglement flux at the analog horizon with ratio F_h/F_far = 83.2× under optimized error mitigation (44.3× under standard reproducible conditions); (ii) temporal causality with monotonic signal development (R² > 0.99); (iii) the characteristic ⟨XX⟩ ≈ -⟨YY⟩ anti-correlation signature (r = 0.997) consistent with squeezed pair production; and (iv) effective temperature scaling β ∝ 1/κ consistent with the Hawking relation. Statistical validation via shuffle control demonstrates 91.6% signal degradation under random bit permutation (p < 0.001), providing strong evidence that the observed signal relies on multi-qubit spatial correlations consistent with XY dynamics. Multi-scale validation across 20-80 qubits confirms 100% peak position accuracy at the horizon. We emphasize that our results demonstrate kinematic analogs—spatial localization and pair-correlation signatures—not thermodynamic Hawking temperature. The bond correlator F(link) = ⟨XX⟩ + ⟨YY⟩ serves as a transport proxy; Bell-CHSH analysis yields S ≈ 0.4 < 2, confirming correlations without certified entanglement. All experimental data, including IBM Quantum job identifiers, are provided for independent verification. Key Results (Bullet Summary for Cover Letter) 156-qubit Hawking analog — Largest quantum simulation of analog Hawking radiation to date 83.2× flux localization ratio — Order of magnitude above detection threshold (10×) O(1) depth scaling — MHIL architecture enables 20→156 qubit scaling in constant depth 91.6% shuffle validation — Rigorous statistical control ruling out marginal artifacts Multi-scale reproducibility — Validated across Mini (20q), Medium (40q), Large (80q) configurations Full transparency — All IBM Quantum job IDs provided for external verification PACS / Subject Codes 03.67.Ac (Quantum algorithms, protocols, and simulations) 04.70.Dy (Quantum aspects of black holes, evaporation, thermodynamics) 75.10.Pq (Spin chain models)