Experimental demonstration of quantum causal inference via noninvasive measurements

• URL: http://arxiv.org/abs/2411.06051v1
• Date: Sat, 09 Nov 2024 03:29:44 GMT
• Title: Experimental demonstration of quantum causal inference via noninvasive measurements
• Abstract summary: We probe whether causal structure can be determined without intervention in quantum systems. We demonstrate the experimental discrimination between several possible causal structures for a bipartite quantum system at two times.
• Score: 2.649823756203203
• License: http://creativecommons.org/licenses/by-nc-sa/4.0/
• Abstract: We probe the foundations of causal structure inference experimentally. The causal structure concerns which events influence other events. We probe whether causal structure can be determined without intervention in quantum systems. Intervention is commonly used to determine causal structure in classical scenarios, but in the more fundamental quantum theory, there is evidence that measurements alone, even coarse-grained measurements, can suffice. We demonstrate the experimental discrimination between several possible causal structures for a bipartite quantum system at two times, solely via coarse-grained projective measurements. The measurements are implemented by an approach known as scattering circuits in a nuclear magnetic resonance platform. Using recent analytical methods the data thus gathered is sufficient to determine the causal structure. Coarse-grained projective measurements disturb the quantum state less than fine-grained projective measurements and much less than interventions that reset the system to a fixed state.

Related papers

• The quantum mechanics of experiments [45.88028371034407]
  The dissipative nature of the quantum-mechanical time-evolution of averages of states over large ensembles of identical isolated systems is discussed.<n>The importance of dissipation for the successful completion of measurements is highlighted.<n>A solution of the Measurement Problem'' is sketched in an idealized model of a double-slit experiment.
  arXiv  Detail & Related papers  (2026-03-26T11:25:21Z)
• Measuring unconventional causal structures in monitored dynamics [7.280769022083202]
  We study the causal structure and emergent "arrow of time" in monitored quantum dynamics.<n>We propose a new measure, the cross-entropy quantum causal influence, to quantify the extent of causal influence.
  arXiv  Detail & Related papers  (2026-01-18T05:58:19Z)
• Measurement-induced crossover in quantum first-detection times [39.98742834565653]
  We show that the measurement back action intrinsic to quantum mechanics may profoundly alter the system dynamics.<n>For a quantum particle in one spatial dimension subject to stroboscopic measurements, we observe an algebraic decay of the probability of the first-detection time if the particle is free.<n>This crossover reflects the purely quantum nature of the detection process, which fundamentally distinguishes it from the first-passage problem in classical systems.
  arXiv  Detail & Related papers  (2026-01-17T16:48:07Z)
• Probing the Physical Reality of Projective Measurements [0.0]
  We test whether the postulate of a measurement acting as an instantaneous projection onto an eigenstate of the measurement apparatus is compatible with physical reality.<n>We also develop a continuous description of a quantum measurement finding that its repeated-measurement statistics drastically differ from the projective case.
  arXiv  Detail & Related papers  (2025-06-25T17:04:55Z)
• Theory of the correlated quantum Zeno effect in a monitored qubit dimer [41.94295877935867]
  We show how the competition between two measurement processes give rise to two distinct Quantum Zeno (QZ) regimes. We develop a theory based on a Gutzwiller ansatz for the wavefunction that is able to capture the structure of the Hilbert phase diagram. We show how the two QZ regimes are intimately connected to the topology of the flow of the underlying non-Hermitian Hamiltonian governing the no-click evolution.
  arXiv  Detail & Related papers  (2025-03-28T19:44:48Z)
• Entanglement and purity can help to detect systematic experimental errors [28.632544413532923]
  We develop a direct and efficient method to detect systematic errors in quantum experiments.<n>Our results show that entanglement as well as quantum states with a high purity can help to identify systematic errors.
  arXiv  Detail & Related papers  (2025-03-12T15:05:06Z)
• Quantum causal inference via scattering circuits in NMR [2.649823756203203]
  Causal structure refers to which events influence others and in the quantum case corresponds to different quantum circuit structures. We demonstrate via scattering circuit experiments that coarse-grained measurements alone suffice for determining the causal structure.
  arXiv  Detail & Related papers  (2024-11-09T03:30:19Z)
• A computational test of quantum contextuality, and even simpler proofs of quantumness [43.25018099464869]
  We show that an arbitrary contextuality game can be compiled into an operational "test of contextuality" involving a single quantum device. Our work can be seen as using cryptography to enforce spatial separation within subsystems of a single quantum device.
  arXiv  Detail & Related papers  (2024-05-10T19:30:23Z)
• Testing trajectory-based determinism via time probability distributions [41.99844472131922]
  We introduce a prescription for constructing an arrival-time probability distribution within generic trajectory-equipped theories.<n>We derive a conditional probability distribution that is unreachable by quantum mechanics.<n>Our results can be tested experimentally, thereby assessing the validity of trajectory-based determinism.
  arXiv  Detail & Related papers  (2024-04-15T11:36:38Z)
• Effect of the readout efficiency of quantum measurement on the system entanglement [44.99833362998488]
  We quantify the entanglement for a particle on a 1d quantum random walk under inefficient monitoring. We find that the system's maximal mean entanglement at the measurement-induced quantum-to-classical crossover is in different ways by the measurement strength and inefficiency.
  arXiv  Detail & Related papers  (2024-02-29T18:10:05Z)
• Enhanced Entanglement in the Measurement-Altered Quantum Ising Chain [46.99825956909532]
  Local quantum measurements do not simply disentangle degrees of freedom, but may actually strengthen the entanglement in the system. This paper explores how a finite density of local measurement modifies a given state's entanglement structure.
  arXiv  Detail & Related papers  (2023-10-04T09:51:00Z)
• Evolution of many-body systems under ancilla quantum measurements [58.720142291102135]
  We study the concept of implementing quantum measurements by coupling a many-body lattice system to an ancillary degree of freedom. We find evidence of a disentangling-entangling measurement-induced transition as was previously observed in more abstract models.
  arXiv  Detail & Related papers  (2023-03-13T13:06:40Z)
• Can the double-slit experiment distinguish between quantum interpretations? [0.0]
  There are various predictions for joint distribution of particle detection events on a screen which are derived from different formulations and interpretations of the quantum theory. Although the differences are typically small, our studies show that these predictions can be experimentally distinguished by an unconventional double-slit configuration. This experiment would enrich our understanding of the foundations of quantum mechanics.
  arXiv  Detail & Related papers  (2023-01-06T18:35:58Z)
• BaCaDI: Bayesian Causal Discovery with Unknown Interventions [118.93754590721173]
  BaCaDI operates in the continuous space of latent probabilistic representations of both causal structures and interventions. In experiments on synthetic causal discovery tasks and simulated gene-expression data, BaCaDI outperforms related methods in identifying causal structures and intervention targets.
  arXiv  Detail & Related papers  (2022-06-03T16:25:48Z)
• Efficient Distinction between Quantum Direct and Common Causes and its Experimental Verification [15.082156478846654]
  We introduce a quantity named Causal Determinant' to efficiently identify the quantum causal structures between two quantum systems. According to the causal determinant, the quantum direct cause imposed by an arbitrary unitary operator can be perfectly discriminated with the quantum common cause.
  arXiv  Detail & Related papers  (2022-03-05T14:12:37Z)
• Quantum Causal Inference in the Presence of Hidden Common Causes: an Entropic Approach [34.77250498401055]
  We put forth a new theoretical framework for merging quantum information science and causal inference by exploiting entropic principles. We apply our proposed framework to an experimentally relevant scenario of identifying message senders on quantum noisy links. This approach can lay the foundations of identifying originators of malicious activity on future multi-node quantum networks.
  arXiv  Detail & Related papers  (2021-04-24T22:45:50Z)
• Entanglement detection in quantum many-body systems using entropic uncertainty relations [0.0]
  We study experimentally accessible lower bounds on entanglement measures based on entropic uncertainty relations. We derive an improved entanglement bound for bipartite systems, which requires measuring joint probability distributions in only two different measurement settings per subsystem.
  arXiv  Detail & Related papers  (2021-01-21T20:50:11Z)
• Quantum decoherence by Coulomb interaction [58.720142291102135]
  We present an experimental study of the Coulomb-induced decoherence of free electrons in a superposition state in a biprism electron interferometer close to a semiconducting and metallic surface. The results will enable the determination and minimization of specific decoherence channels in the design of novel quantum instruments.
  arXiv  Detail & Related papers  (2020-01-17T04:11:44Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.