Decoherence remains the principal obstacle to practical quantum computation in superconducting architectures, where environmental noise and measurement backaction conspire to collapse fragile quantum states on timescales far shorter than those required for fault-tolerant operation. While the Quantum Zeno Effect offers a measurement-based mechanism for coherence stabilization, and discrete Floquet time crystals provide a framework for sustained periodic oscillation under driven dynamics, the question of whether these two phenomena can be synchronized to actively lock a qubit state against decoherence has remained unaddressed experimentally. Here we report hardware-validated observations of a reproducible coherence anomaly on IBM Quantum processors ibm_marrakesh and ibm_kingston. We identify a consistent coherence dip at Zeno period 3, reproduced across two distinct backends, interpreted as a destructive subharmonic resonance — designated the O’Reilly Effect. We further identify the Harmonic Juncture as a candidate mechanism for coherence extension, suggesting a pathway toward time-crystal-assisted quantum memory.
Decoherence remains the principal obstacle to practical quantum computation in superconducting architectures, where environmental noise and measurement backaction conspire to collapse fragile quantum states on timescales far shorter than those required for fault-tolerant operation. While the Quantum Zeno Effect offers a measurement-based mechanism for coherence stabilization, and discrete Floquet time crystals provide a framework for sustained periodic oscillation under driven dynamics, the question of whether these two phenomena can be synchronized to actively lock a qubit state against decoherence has remained unaddressed experimentally. Here we report hardware-validated observations of a reproducible coherence anomaly on IBM Quantum processors ibm_marrakesh and ibm_kingston. We identify a consistent coherence dip at Zeno period 3, reproduced across two distinct backends, interpreted as a destructive subharmonic resonance — designated the O’Reilly Effect. We further identify the Harmonic Juncture as a candidate mechanism for coherence extension, suggesting a pathway toward time-crystal-assisted quantum memory.
ABSTRACT The quantum Zeno effect, in which frequent measurements suppress the evolution of a quantum system, is well characterized for static Hamiltonians. We investigate how periodic driving modifies Zeno protection for a single qubit on the superconducting processor ibm_marrakesh . In our gate‐based protocol, an interrupted Rabi oscillation is combined with a digitized longitudinal drive of frequency and amplitude , and the number of projective measurements, , is varied. Strong driving (, , dimensionless circuit units) enhances peak survival at the optimal measurement number by approximately relative to the undriven case, and reduces the effective per‐interval decay rate by up to . The relative enhancement was reproduced across two sessions separated by a recalibration cycle ( and , consistent within the statistical uncertainty), while absolute survival shifted by about 18 percentage points, identifying the relative enhancement as the robust quantity. Exact noiseless predictions computed from the Trotterized circuit unitaries track the hardware data with a consistent decoherence offset. A Trotter‐step control experiment shows that an apparent single‐measurement survival anomaly under fast driving () is a discretization artifact, illustrating the need for convergence verification when digitizing periodic drives.
The simulation of non-equilibrium quantum many-body systems on noisy intermediate-scale quantum (NISQ) processors represents a central challenge and opportunity in modern condensed matter physics. Periodically driven (Floquet) systems can host exotic phases of matter with no equilibrium counterpart, most notably discrete time crystals (DTCs) characterized by spontaneous breaking of discrete time-translation symmetry and robust subharmonic responses. However, the realization of DTCs faces fundamental obstacles: driven many-body systems generically absorb energy and thermalize to an infinite-temperature state, destroying time-crystalline order. Two primary mechanisms have been identified to stabilize DTCs—many-body localization (MBL) through strong disorder, and Floquet prethermalization wherein high-frequency driving suppresses heating over exponentially long timescales. This work investigates the digital quantum simulation of prethermal DTCs on current superconducting quantum processors, with a focus on understanding and mitigating the impact of hardware noise. Recent experiments on 133-qubit heavy-hexagonal devices have demonstrated the realization of clean two-dimensional DTCs and incommensurately modulated DTCs (IM-DTCs) using kicked Ising models, observing period-doubling oscillations persisting for up to 100 Floquet cycles . Crucially, these simulations reveal that quantum noise, often perceived as detrimental, can in certain regimes stabilize novel prethermal DTC phases—a phenomenon identified as noise-induced DTCs supported by symmetry charge pumping or random gate fluctuations . The heavy-hexagonal lattice geometry, compared to square lattices, exhibits significantly slower quantum scrambling, thereby extending the prethermal plateau and enhancing DTC stability. We address two key challenges limiting the scalability of DTC simulations: limited qubit connectivity and environmental noise. By leveraging the universality of native gate sets, we demonstrate how to implement effective couplings among physically disconnected qubits at the cost of increased circuit depth, enabling the study of interaction-range effects on DTC stabilization—a phenomenon previously unobserved experimentally . Furthermore, we benchmark the performance of error mitigation protocols based on depolarising noise models, achieving excellent agreement between error-mitigated hardware data and tensor-network simulations in regimes where classical computations remain tractable . Our results highlight the complementary roles of quantum hardware and classical simulation: quantum processors provide access to regimes where entanglement growth outpaces tensor-network methods, while careful validation against classical benchmarks ensures the reliability of quantum outcomes. This study establishes a concrete pathway for using NISQ devices as experimental platforms for synthesizing and probing novel non-equilibrium quantum phases, advancing both our fundamental understanding of Floquet many-body dynamics and the practical capabilities of quantum simulation. The identification of noise as an active ingredient in phase stabilization suggests new directions for quantum engineering of spatiotemporal orders on near-term hardware.
This paper investigates the intersection of non-equilibrium quantum dynamics and time-symmetric mechanics by evaluating topological coherence extension through Floquet-driven discrete time crystals (DTC) coupled with Two-State Vector Formalism (TSVF) metric perturbations. By modeling complex temporal boundary constraints within a simulated manifold architecture, we demonstrate that periodic driving layers and retrocausally-modulated metric tensors can significantly mitigate decoherence and yield enhanced coherence amplitudes against environmental noise.
Floquet many-body phases such as discrete time crystals (DTCs) are typically fragile to imperfections, and stabilizing them on noisy quantum hardware remains a central challenge in nonequilibrium quantum physics. Here, we use IBM Eagle and Heron superconducting processors to implement Floquet dynamics of a kicked Ising model on two-dimensional Kagome lattices, engineered via ancilla-assisted embeddings into the heavy-hex connectivity of the devices. By combining error-mitigated measurements on quantum hardware with matrix-product-state simulations incorporating an ancilla-noise model constructed from experimental device data, we observe long-lived subharmonic magnetization oscillations that are stabilized -- rather than destroyed -- by structured quantum noise. Across different two-dimensional lattice geometries, increasing cases beyond Kagome lattices, and with or without boundary symmetry-charge pumping, ancilla errors effectively act as spatiotemporal disorder that induces stochastic sign flips of the Ising couplings, providing a unified mechanism for robust period-doubling responses. When symmetry-charge pumping is present, intrinsic boundary-localized π modes cooperate with this disorder to yield a boundary-assisted DTC characterized by suppressed scrambling and sharply localized dynamics. In contrast, in implementations without pumping, the noiseless dynamics rapidly thermalize and exhibit no subharmonic order, whereas the same noise process alone generates a DTC-like long-lived subharmonic response over experimentally accessible time windows. These results identify engineered ancilla noise as a practical control knob for inducing, stabilizing, and geometrically tailoring nonequilibrium dynamical order on scalable superconducting quantum processors.
Observing a 3T discrete time crystal on a trapped-ion qudit quantum processor
Time crystals have been observed in various qubit-based quantum platforms. However, the realization of time-crystal behavior beyond period doubling has remained fairly unexplored, in part because established qubit architectures natively encode two-cycle dynamics. Qudits offer a natural route beyond this restriction. Here we propose a one-dimensional, disorder-free S=1 Floquet model with short-range interactions that realizes a discrete 3T time crystal and implement it on a trapped-ion qudit quantum processor. We observe period tripling dynamics in local observables and spin correlations, confirming the collective subharmonic response of the system in the experiment. The stabilization mechanism is analyzed by deriving the effective Floquet Hamiltonian and performing numerical simulations that demonstrate the existence of a prethermal phase over a wide range of parameters. We compute the phase diagram and verify the presence of multipartite entanglement through the Quantum Fisher Information, showing that this quantity gets enhanced at the crossover between ergodic and localized regimes in non-equilibrium.
Current quantum computing architectures rely predominantly on “Passive Isolation” strategies such as dilution refrigeration and electromagnetic shielding to protect qubit coherence. However, the persistence of residual noise suggests that static isolation is insufficient against the dynamic fluctuations of space-time. This paper presents a novel protocol for “Active Quantum Synchronization” based on the principles of Floquet Engineering and Harmonic Resonance. Analogous to dynamic stabilization systems in maritime engineering, we propose injecting a specific harmonic carrier wave (derived from Field C) into the quantum system. This driving force locks the qubit’s internal phase to the environmental background frequency, cancelling out decoherence through constructive interference and creating a phase locked stability zone.