We investigate measurement-induced effects on trans-horizon correlations in dynamic quantum circuits executed on IBM's 156-qubit superconducting processor (ibm_fez, Heron r2 architecture). We engineer a 40-qubit spin chain with a spatially-varying XX + YY coupling profile that creates an analog horizon at position xh = 20, where coupling strength reaches a minimum. We define a correlation contrast metric C = ⟨σxiσxj⟩horizon − ⟨σxσx⟩exterior and compare three conditions: (i) unitary Trotter evolution (baseline), (ii) mid-circuit measurement with reset on qubits near the horizon, and (iii) control measurement on distant qubits. Each circuit was executed with 16,384 shots. The near-horizon measurement produces a (56.5 ± 1.9)% reduction in correlation contrast (95% CI from n = 5000 bootstrap resamples), while the control preserves (87.8 ± 2.1)% of baseline. Two ablation experiments constrain interpretation: removing the reset operation yields only a (2.6 ± 1.2) percentage point change, indicating that projective measurement—not state reset—drives the effect. Crucially, moving the measured subset 4 links away from the horizon collapses the reduction to (6.5 ± 2.3)%, yielding an 8.2 ± 1.4 ratio that demonstrates strong spatial localization. We additionally performed a flat-spacetime control with uniform coupling J(x) = Jmax on ibm_torino (Heron r1, 133 qubits), obtaining a baseline contrast that collapses to a small residual near zero (C = − 0.015, 95% CI [− 0.029, − 0.002]), confirming that the spatial structure arises from the engineered coupling profile rather than generic measurement artifacts. These results establish that mid-circuit measurement near an engineered coupling minimum preferentially disrupts correlations across that boundary, a signature qualitatively consistent with information-theoretic models of horizon physics.
We investigate measurement-induced effects on trans-horizon correlations in dynamic quantum circuits executed on IBM's 156-qubit superconducting processor (ibm_fez, Heron r2 architecture). We engineer a 40-qubit spin chain with a spatially-varying XX + YY coupling profile that creates an analog horizon at position xh = 20, where coupling strength reaches a minimum. We define a correlation contrast metric C = ⟨σxiσxj⟩horizon − ⟨σxσx⟩exterior and compare three conditions: (i) unitary Trotter evolution (baseline), (ii) mid-circuit measurement with reset on qubits near the horizon, and (iii) control measurement on distant qubits. Each circuit was executed with 16,384 shots. The near-horizon measurement produces a (56.5 ± 1.9)% reduction in correlation contrast (95% CI from n = 5000 bootstrap resamples), while the control preserves (87.8 ± 2.1)% of baseline. Two ablation experiments constrain interpretation: removing the reset operation yields only a (2.6 ± 1.2) percentage point change, indicating that projective measurement—not state reset—drives the effect. Crucially, moving the measured subset 4 links away from the horizon collapses the reduction to (6.5 ± 2.3)%, yielding an 8.2 ± 1.4 ratio that demonstrates strong spatial localization. We additionally performed a flat-spacetime control with uniform coupling J(x) = Jmax on ibm_torino (Heron r1, 133 qubits), obtaining a baseline contrast that collapses to a small residual near zero (C = − 0.015, 95% CI [− 0.029, − 0.002]), confirming that the spatial structure arises from the engineered coupling profile rather than generic measurement artifacts. These results establish that mid-circuit measurement near an engineered coupling minimum preferentially disrupts correlations across that boundary, a signature qualitatively consistent with information-theoretic models of horizon physics.
Abstract We investigate measurement-induced effects on trans-horizon correlations in dynamic quantum circuits executed on IBM's 156-qubit superconducting processor (ibm_fez, Heron r2 architecture). We engineer a 40-qubit spin chain with a spatially-varying XX + YY coupling profile that creates an analog horizon at position x h = 20, where coupling strength reaches a minimum. We define a correlation contrast metric C = ⟨σ x iσ x j⟩ horizon − ⟨σ x σ x ⟩ exterior and compare three conditions: (i) unitary Trotter evolution (baseline), (ii) mid-circuit measurement with reset on qubits near the horizon, and (iii) control measurement on distant qubits. Each circuit was executed with 16,384 shots. The near-horizon measurement produces a (56.5 ± 1.9)% reduction in correlation contrast (95% CI from n = 5000 bootstrap resamples), while the control preserves (87.8 ± 2.1)% of baseline. Two ablation experiments constrain interpretation: removing the reset operation yields only a (2.6 ± 1.2) percentage point change, indicating that projective measurement—not state reset—drives the effect. Crucially, moving the measured subset 4 links away from the horizon collapses the reduction to (6.5 ± 2.3)%, yielding an 8.2 ± 1.4 ratio that demonstrates strong spatial localization. We additionally performed a flat-spacetime control with uniform coupling J(x) = J max on ibm_torino (Heron r1, 133 qubits), obtaining a baseline contrast that collapses to a small residual near zero (C = − 0.015, 95% CI [− 0.029, − 0.002]), confirming that the spatial structure arises from the engineered coupling profile rather than generic measurement artifacts. These results establish that mid-circuit measurement near an engineered coupling minimum preferentially disrupts correlations across that boundary, a signature qualitatively consistent with information-theoretic models of horizon physics.
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)
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.
We report a gate-based quantum circuit that implements a qubit-truncated analog of pair creation, inspired by Hawking radiation phenomenology, and demonstrate certified Bell nonlocality on IBM Quantum hardware (ibm_fez, Heron R2, 156 qubits). Using a two-mode squeezing (TMS) gate mapping |00⟩ to cos(θ/2)|00⟩ + sin(θ/2)|11⟩, we generate entangled pairs across a designated ‘horizon’ position in a 20-qubit chain.Main results: CHSH Bell parameter S = 2.290 ± 0.010 (29.8σ shot-noise; >22σ conservative with systematics), entanglement witness W = 2.838 ± 0.004, and Bell-state fidelity F(|Φ⁺⟩) = 96%. Bootstrap resampling (10,000 iterations) confirms robustness (100% of samples violate classical bounds).Important caveat: this is a protocol demonstration for gravity-inspired entanglement certification on NISQ hardware, not a faithful simulation of Hawking radiation (no thermal spectrum / vacuum structure).
ABSTRACT We report a systematic, measurement-induced irreversibility in superconducting quantum circuits that is not accounted for by any tested conventional noise model. Using IBM Quantum processors (ibm_marrakesh and ibm_kingston), we implement a time-reversal protocol in which mid-circuit measurements are inserted between a unitary U and its inverse U†. The fidelity deficit ΔF = F(dummy) − F(meas) grows linearly with measurement count M, reaching ΔF = 0.235 (22.2σ) and ΔF = 0.164 (24.0σ) at M = 8 on the two processors. Three independent controls rule out conventional noise sources: (1) T-independence of the spectator-qubit phase shift (dA ≈ +0.10 at T = 40 and 80 μs) eliminates crosstalk and leakage; (2) a non-Markovian symmetry test (spread = 1.5σ) eliminates decoherence asymmetry; and (3) cross-backend reproducibility of the linear ΔF(M) scaling eliminates hardware-specific measurement noise. The three observations share a common structural feature: the irreversibility is tied to discrete measurement events rather than free-evolution time, accumulates proportionally to their count, and reproduces across independent hardware. We report these observations as experimental evidence consistent with the interpretation that the imaginary unit i in the Schrödinger equation reflects a physically real internal structure of time, and that quantum measurement drives an irreversible projection of that structure onto the real axis. This interpretation is developed from first principles in Sec. II and connected to an existing theoretical framework [13] in Sec. VI. Keywordsquantum computing, mid-circuit measurement, complex time, irreversibility, IBM Quantum, time-reversal protocol
Black holes are conventionally described as gravitational objects defined by spacetime geometry and event horizons. This geometric picture, while successful, leaves open fundamental questions concerning irreversibility, information isolation, and the universality of horizon-like behavior across physical systems. In this work, we propose and experimentally test an alternative framework: that horizon-like structures emerge as a consequence of realization dynamics, independent of gravity or spacetime curvature. By realization we mean the physical persistence of quantum structure under ongoing dynamics, as distinct from its mere mathematical existence in Hilbert space. Quantum structure that cannot be dynamically realized must be structurally excluded from the realizable domain. We implement a realization-based dynamical protocol on real superconducting quantum hardware provided by IBM Quantum, using sampler-native circuits without mid-circuit measurements or post-selection. A small quantum “world” subsystem is coupled to a non-realizable sink via a controllable realization barrier. Population of the sink qubit serves as an empirical signature of horizon-like absorption. Three regimes are experimentally compared: a fully realizable regime, a control regime with strong dynamics but no realization barrier, and a horizon regime in which unstable quantum structure is coherently redirected into the sink. Strong absorption is observed exclusively in the presence of the realization barrier, while the realizable and control regimes remain statistically indistinguishable. Control tests rule out noise, circuit depth, or strong driving as alternative explanations. These results constitute hardware-executed evidence that black-hole-like horizons can emerge purely from realization dynamics. We conclude that black holes may be understood as structural residues of completed realization rather than objects requiring gravitational collapse, opening a new experimental route to horizon physics grounded in quantum realization rather than geometry.