Conditions for implementing projective measurements through continuous monitoring

• URL: http://arxiv.org/abs/2608.09639v1
• Date: Mon, 10 Aug 2026 14:21:04 GMT
• Title: Conditions for implementing projective measurements through continuous monitoring
• Abstract summary: Projective measurements are foundational for quantum physics in general and quantum information tasks in particular.<n>We investigate under what conditions continuous monitoring that manifests in quantum jump trajectories realises projective measurements over time.<n>Our results provide a transparent framework for understanding the emergence of projective measurements from continuous monitoring.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Projective measurements are foundational for quantum physics in general and quantum information tasks in particular. However, their direct implementation is often not warranted. Here, we investigate under what conditions continuous monitoring that manifests in quantum jump trajectories realises projective measurements over time. Considering finite-dimensional quantum systems and single, diagonalisable jump operators, we show if and how the detected quantum jump statistics force, and allow inferring, the convergence of individual quantum trajectories towards eigenstates of an observable in the long-time limit. We identify a necessary non-degeneracy condition that is related to the presence of a strong symmetry with non-degenerate symmetry sectors. We derive analytical expressions for the rate of convergence and the time-error relationship in finite-time measurements. Our results provide a transparent framework for understanding the emergence of projective measurements from continuous monitoring, with direct implications for the optimisation of quantum measurement protocols in experiments.

Related papers

• Detecting nonequilibrium phase transitions via continuous monitoring of space-time trajectories and autoencoder-based clustering [0.0]
  We present a machine-learning approach to detect nonequilibrium phase transitions in quantum systems.<n>We benchmark our method using the quantum contact process, a model featuring an absorbing-state phase transition.
  arXiv  Detail & Related papers  (2026-02-19T13:19:35Z)
• An introduction to monitored quantum systems and quantum trajectories: spectrum, typicality, and phases [0.0]
  We provide an introductory theoretical review on the basic formalisms governing open quantum dynamics under measurement.<n>We introduce the concept of quantum trajectories, which are the conditional dynamics of monitored states shaped by a set of measurement outcomes.<n>Lyapunov exponents of typical quantum trajectories serve as indicators of measurement-induced phase transitions in monitored quantum many-body systems.
  arXiv  Detail & Related papers  (2025-12-22T22:59:16Z)
• Machine learning the effects of many quantum measurements [0.5973423278489198]
  We create entangled states of one- and two-dimensional arrays of qubits in a superconducting quantum processor.<n>We aim to characterize the long-range entanglement induced between distant pairs of qubits when we measure all of the others.
  arXiv  Detail & Related papers  (2025-09-10T18:00:05Z)
• 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)
• Work Statistics and Quantum Trajectories: No-Click Limit and non-Hermitian Hamiltonians [50.24983453990065]
  We present a framework for quantum work statistics in continuously monitored quantum systems.<n>Our approach naturally incorporates non-Hermitian dynamics arising from quantum jump processes.<n>We illustrate our theoretical framework by analyzing a one-dimensional transverse-field Ising model under local spin monitoring.
  arXiv  Detail & Related papers  (2025-04-15T23:21:58Z)
• Unraveling the emergence of quantum state designs in systems with symmetry [15.699822139827916]
  We study the emergence of state designs from the random generator states exhibiting symmetries. We find faster convergence of the trace distance during the early time evolution in comparison to the cases when the symmetry is broken. We expect our findings to pave the way for further exploration of deep thermalization and equilibration of closed and open quantum many-body systems.
  arXiv  Detail & Related papers  (2024-02-14T05:35:03Z)
• Continuously Monitored Quantum Systems beyond Lindblad Dynamics [68.8204255655161]
  We study the probability distribution of the expectation value of a given observable over the possible quantum trajectories. The measurements are applied to the entire system, having the effect of projecting the system into a product state.
  arXiv  Detail & Related papers  (2023-05-06T18:09:17Z)
• Quantifying measurement-induced quantum-to-classical crossover using an open-system entanglement measure [49.1574468325115]
  We study the entanglement of a single particle under continuous measurements. We find that the entanglement at intermediate time scales shows the same qualitative behavior as a function of the measurement strength.
  arXiv  Detail & Related papers  (2023-04-06T09:45:11Z)
• Measurement-induced entanglement and teleportation on a noisy quantum processor [105.44548669906976]
  We investigate measurement-induced quantum information phases on up to 70 superconducting qubits. We use a duality mapping, to avoid mid-circuit measurement and access different manifestations of the underlying phases. Our work demonstrates an approach to realize measurement-induced physics at scales that are at the limits of current NISQ processors.
  arXiv  Detail & Related papers  (2023-03-08T18:41:53Z)
• Observation of partial and infinite-temperature thermalization induced by repeated measurements on a quantum hardware [62.997667081978825]
  We observe partial and infinite-temperature thermalization on a quantum superconducting processor. We show that the convergence does not tend to a completely mixed (infinite-temperature) state, but to a block-diagonal state in the observable basis.
  arXiv  Detail & Related papers  (2022-11-14T15:18:11Z)
• Measurement-induced quantum criticality under continuous monitoring [0.0]
  We investigate entanglement phase transitions from volume-law to area-law entanglement in a quantum many-body state under continuous position measurement. We find the signatures of the transitions as peak structures in the mutual information as a function of measurement strength. We propose a possible experimental setup to test the predicted entanglement transition based on the subsystem particle-number fluctuations.
  arXiv  Detail & Related papers  (2020-04-24T19:35:28Z)
• Quantum Zeno effect appears in stages [64.41511459132334]
  In the quantum Zeno effect, quantum measurements can block the coherent oscillation of a two level system by freezing its state to one of the measurement eigenstates. We show that the onset of the Zeno regime is marked by a $textitcascade of transitions$ in the system dynamics as the measurement strength is increased.
  arXiv  Detail & Related papers  (2020-03-23T18:17:36Z)
• Entropic Uncertainty Relations and the Quantum-to-Classical transition [77.34726150561087]
  We aim to shed some light on the quantum-to-classical transition as seen through the analysis of uncertainty relations. We employ entropic uncertainty relations to show that it is only by the inclusion of imprecision in our model of macroscopic measurements that we can prepare a system with two simultaneously well-defined quantities.
  arXiv  Detail & Related papers  (2020-03-04T14:01:17Z)

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.