It has been suggested in the literature that spatial coherence of the wave function can be dynamically suppressed by fluctuations in the spacetime geometry. These fluctuations represent the minimal uncertainty that is present when one probes spacetime geometry with a quantum probe. Two similar models have been proposed, one by Diósi [D-model] and one by Karolyhazy and collaborators [K-model], based on apparently unrelated minimal spacetime bounds. The two models arrive at somewhat different expressions for the dependence of the localization coherence length on the mass and size of the quantum object. In the present article we compare and contrast the two models from three aspects: (i) comparison of the spacetime bounds, (ii) method of calculating decoherence time, (iii) comparison of noise correlation. We show that under certain conditions the minimal spacetime bounds in the two models can be derived one from the other. We argue that the methods of calculating the decoherence time are equivalent. We re-derive the two-point correlation for the fluctuation potential in the K-model, and confirm the earlier result of Diósi and Lukács that it is non-white noise, unlike in the D-model, where the corresponding correlation is white noise in time. This seems to be the origin of the different results in the two models. We derive the non-Markovian master equation for the K-model. We argue that the minimal spacetime bound cannot predict the noise correlation uniquely, and additional criteria are necessary to accurately determine the effects of gravitationally induced decoherence.It has been suggested in the literature that spatial coherence of the wave function can be dynamically suppressed by fluctuations in the spacetime geometry. These fluctuations represent the minimal uncertainty that is present when one probes spacetime geometry with a quantum probe. Two similar models have been proposed, one by Diósi [D-model] and one by Karolyhazy and collaborators [K-model], based on apparently unrelated minimal spacetime bounds. The two models arrive at somewhat different expressions for the dependence of the localization coherence length on the mass and size of the quantum object. In the present article we compare and contrast the two models from three aspects: (i) comparison of the spacetime bounds, (ii) method of calculating decoherence time, (iii) comparison of noise correlation. We show that under certain conditions the minimal spacetime bounds in the two models can be derived one from the other. We argue that the methods of calculating the decoherence time are equivalent. We re-derive the two-point correlation for the fluctuation potential in the K-model, and confirm the earlier result of Diósi and Lukács that it is non-white noise, unlike in the D-model, where the corresponding correlation is white noise in time. This seems to be the origin of the different results in the two models. We derive the non-Markovian master equation for the K-model. We argue that the minimal spacetime bound cannot predict the noise correlation uniquely, and additional criteria are necessary to accurately determine the effects of gravitationally induced decoherence.

arXiv:1408.1194Aug 6, 20142 citations

QGIDC: The World’s First Quantum Circuit Simulating Gravity-Induced Decoherence on Real Quantum Hardware

Zuhair Ahmed

Abstract This study presents a groundbreaking experimental demonstration of gravity induced decoherence in quantum systems, achieved through the development and execution of the Quantum Gravity-Induced Decoherence Circuit (QGIDC) on IBM quantum hardware. This research provides the first measurable evidence of how gravitational effects can influence quantum entanglement, building upon and ex tending theoretical frameworks proposed by prominent physicists such as Roger Penrose and Gerard ’t Hooft. The experiments were conducted using both Qiskit simulators and real IBM quantum computers, including the advanced IBM Bris bane backend, with multiple repetitions to ensure scientific reproducibility. A com prehensive set of metrics—fidelity, purity, entropy, trace distance, measurement counts, and Bloch vector dynamics—were meticulously analyzed to differentiate gravity-induced noise from standard environmental decoherence. Additionally, a mathematical model is introduced to quantify the decoherence rate, while Bloch sphere visualizations offer a visual representation of qubit state evolution under gravitational influence. This work, completed as of 06:12 PM on Monday, May 19, 2025, marks the first empirical validation of gravity-induced decoherence, estab lishing a significant milestone in the quest to reconcile quantum mechanics with general relativity.Abstract This study presents a groundbreaking experimental demonstration of gravity induced decoherence in quantum systems, achieved through the development and execution of the Quantum Gravity-Induced Decoherence Circuit (QGIDC) on IBM quantum hardware. This research provides the first measurable evidence of how gravitational effects can influence quantum entanglement, building upon and ex tending theoretical frameworks proposed by prominent physicists such as Roger Penrose and Gerard ’t Hooft. The experiments were conducted using both Qiskit simulators and real IBM quantum computers, including the advanced IBM Bris bane backend, with multiple repetitions to ensure scientific reproducibility. A com prehensive set of metrics—fidelity, purity, entropy, trace distance, measurement counts, and Bloch vector dynamics—were meticulously analyzed to differentiate gravity-induced noise from standard environmental decoherence. Additionally, a mathematical model is introduced to quantify the decoherence rate, while Bloch sphere visualizations offer a visual representation of qubit state evolution under gravitational influence. This work, completed as of 06:12 PM on Monday, May 19, 2025, marks the first empirical validation of gravity-induced decoherence, estab lishing a significant milestone in the quest to reconcile quantum mechanics with general relativity.

May 20, 20250 citations

Decoherence due to gravitational time dilation: Analysis of competing decoherence effects

Matteo Carlesso, Angelo Bassi

arXiv:1602.01979Physics Letters AMay 25, 201622 citations

Theory of quantum gravitational decoherence

Teodora Oniga

Jan 1, 20160 citations

Experimental exclusion of a generalized Károlyházy gravity-induced decoherence model

Nicola Bortolotti, Kristian Piscicchia, Matthias Laubenstein +4 more

We report new experimental constraints on the generalized version of the gravity-induced decoherence model originally proposed by Károlyházy. Using data collected by the VIP Collaboration at the INFN Gran Sasso National Laboratory with a high-purity germanium detector, we derive an improved lower bound on the spatial correlation length $R_K$ characterizing metric fluctuations in the model. We obtain a bound $R_K > 4.64$ m (95\% C.L.), which exceeds by more than an order of magnitude the previous experimental limit. When combined with the theoretical upper bound $R_K <1.98$ m derived from macroscopic localization requirements, our result excludes the generalized Károlyházy model. The same conclusion applies to an associated non-Markovian formulation of the Continuous Spontaneous Localization (CSL) model. Our findings significantly tighten experimental constraints on gravity-related decoherence scenarios and demonstrate the sensitivity of underground low-background experiments to foundational modifications of quantum mechanics.We report new experimental constraints on the generalized version of the gravity-induced decoherence model originally proposed by Károlyházy. Using data collected by the VIP Collaboration at the INFN Gran Sasso National Laboratory with a high-purity germanium detector, we derive an improved lower bound on the spatial correlation length $R_K$ characterizing metric fluctuations in the model. We obtain a bound $R_K > 4.64$ m (95\% C.L.), which exceeds by more than an order of magnitude the previous experimental limit. When combined with the theoretical upper bound $R_K <1.98$ m derived from macroscopic localization requirements, our result excludes the generalized Károlyházy model. The same conclusion applies to an associated non-Markovian formulation of the Continuous Spontaneous Localization (CSL) model. Our findings significantly tighten experimental constraints on gravity-related decoherence scenarios and demonstrate the sensitivity of underground low-background experiments to foundational modifications of quantum mechanics.

quant-pharXiv:2601.00651Jan 5, 20260 citations

R_K

characterizing metric fluctuations in the model. We obtain a bound

R_K > 4.64

m (95\% C.L.), which exceeds by more than an order of magnitude the previous experimental limit. When combined with the theoretical upper bound

R_K <1.98

m derived from macroscopic localization requirements, our result excludes the generalized Károlyházy model. The same conclusion applies to an associated non-Markovian formulation of the Continuous Spontaneous Localization (CSL) model. Our findings significantly tighten experimental constraints on gravity-related decoherence scenarios and demonstrate the sensitivity of underground low-background experiments to foundational modifications of quantum mechanics.