Role of inefficient measurement in realizing post-selection-based non-Hermitian qubits

• URL: http://arxiv.org/abs/2510.21159v1
• Date: Fri, 24 Oct 2025 05:16:40 GMT
• Title: Role of inefficient measurement in realizing post-selection-based non-Hermitian qubits
• Abstract summary: We introduce post-selection efficiencies for both decay channels, the second-excited to first-excited and the first-excited to ground-state transitions.<n>We find that the decoherence effects arising from quantum jumps within the second-excited and first-excited manifold also manifest under inefficient post-selection of the second-excited to first-excited transitions.
• Score: 1.0323063834827415
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Post-selecting against quantum jumps into the ground state confines the evolution of the three-level system to the excited states manifold, effectively realizing a PT-symmetric non-Hermitian qubit. In this work, by introducing post-selection efficiencies for both decay channels, the second-excited to first-excited and the first-excited to ground-state transitions, we formulate a hybrid-Liouvillian framework that captures the unmonitored dynamics of the non-Hermitian qubit. We find that the decoherence effects arising from quantum jumps within the second-excited and first-excited manifold also manifest under inefficient post-selection of the second-excited to first-excited transitions, thereby modifying the spectral properties of the Liouvillian and leading to a splitting of the exceptional points. A comparative analysis shows that the trajectory-based approach, obtained by ensemble-averaging stochastic measurement trajectories generated via the Bayesian state update rule, and the Lindblad evolution remain consistent. Our results highlight the fundamental role of measurement inefficiency in realizing post-selection-based non-Hermitian qubits and in shaping the structure of Liouvillian exceptional points. These findings provide new insights into how inefficient measurement processes influence non-Hermitian behavior in open quantum systems.

Related papers

• Experimental Observation of Anomalous Complementary Weak Values from Correlated Pairwise Two-State Vectors [5.145415821268373]
  Weak values (WVs) arise from weak measurements performed within a time-symmetric formulation of quantum mechanics.<n>Anomalous WVs that lie far outside the eigenvalue spectrum of the observable hold both fundamental and practical significance.<n>We utilize quantum entanglement and post-selection-controlled operations to generate correlated pairwise two-state vectors.
  arXiv  Detail & Related papers  (2026-07-13T09:06:33Z)
• Postselection induced localization and coherence in quantum walks on heterogeneous networks [0.0]
  We study the effect of such non-linearity in continuous-time quantum walks (CTQWs) on networks with homogeneous and heterogeneous degree distributions.<n>Our analysis reveals a striking dichotomy: under Haken-Strobl decoherence the nonlinear contributions precisely cancel, yielding a uniform steady state independent of postselection details.<n>In stark contrast, QSW decoherence permits postselection to break dynamical balance on heterogeneous networks, inducing robust localization preferentially at low-degree nodes.
  arXiv  Detail & Related papers  (2026-03-18T11:47:55Z)
• Replica Keldysh field theory of quantum-jump processes: General formalism and application to imbalanced and inefficient fermion counting [0.0]
  We develop a comprehensive replica Keldysh field theory for general quantum-jump processes in bosonic and fermionic systems.<n>Our formalism provides a unified description of pure-state quantum trajectories under efficient detection and mixed-state dynamics.
  arXiv  Detail & Related papers  (2025-12-18T13:34:00Z)
• Nonlinear quantum evolution of a dissipative superconducting qubit [1.0924851843152197]
  Superposition principle can break down in effective non-Hermitian dynamics.<n>We experimentally investigate this breakdown in a dissipative superconducting transmon circuit.<n>Results provide direct evidence of nonlinearity in non-Hermitian quantum evolution.
  arXiv  Detail & Related papers  (2025-10-29T18:00:02Z)
• Homodyne Measurement of a Non-Hermitian Qubit Undergoing Fluorescence [0.0]
  Post-selection procedure generates a non-Hermitian qubit exhibiting PT symmetry.<n>We analyze the interplay between decay introduced by post-selection and measurement backaction.<n>Results provide insights into how measurement backaction and non-Hermitian dynamics together shape the transient behavior of open quantum systems.
  arXiv  Detail & Related papers  (2025-10-15T09:30:43Z)
• Unveiling the Self-Orthogonality at Exceptional Points in Driven $\mathcal{PT}$-Symmetric Systems [79.16635054977068]
  We explore the effect of self-orthogonality at exceptional points (EPs) in non-Hermitian Parity-Time-symmetric systems.<n>Using a driven three-band lattice model, we show that the Rabi frequency diverges as the system approaches an EP due to the coalescence of eigenstates.
  arXiv  Detail & Related papers  (2025-07-14T12:53:10Z)
• 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)
• 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.<n>We develop a theory based on a Gutzwiller ansatz for the wavefunction that is able to capture the structure of the Hilbert phase diagram.<n>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)
• Crossing exceptional points in non-Hermitian quantum systems [41.94295877935867]
  We reveal the behavior of two-photon quantum states in non-Hermitian systems across the exceptional point. We demonstrate a switching in the quantum interference of photons directly at the exceptional point.
  arXiv  Detail & Related papers  (2024-07-17T14:04:00Z)
• Theory of free fermions dynamics under partial post-selected monitoring [49.1574468325115]
  We derive a partial post-selected Schrdinger"o equation based on a microscopic description of continuous weak measurement. We show that the passage to the monitored universality occurs abruptly at finite partial post-selection. Our approach establishes a way to study MiPTs for arbitrary subsets of quantum trajectories.
  arXiv  Detail & Related papers  (2023-12-21T16:53:42Z)
• Free fermions under adaptive quantum dynamics [6.566869568708405]
  We study free fermion systems under adaptive quantum dynamics consisting of unitary gates and projective measurements.<n>We find that the corrective unitary operations can steer the system into a state characterized by charge-density-wave order.
  arXiv  Detail & Related papers  (2023-06-28T23:09:59Z)
• Pontryagin-Optimal Control of a non-Hermitian Qubit [0.0]
  We study the control of a single non-Hermitian qubit. We show how to realize any continuous and differentiable pure-state trajectory in the dynamics of a qubit conditioned on no emission.
  arXiv  Detail & Related papers  (2022-08-04T20:51:29Z)
• On optimization of coherent and incoherent controls for two-level quantum systems [77.34726150561087]
  This article considers some control problems for closed and open two-level quantum systems. The closed system's dynamics is governed by the Schr"odinger equation with coherent control. The open system's dynamics is governed by the Gorini-Kossakowski-Sudarshan-Lindblad master equation.
  arXiv  Detail & Related papers  (2022-05-05T09:08:03Z)
• Non-Gaussian superradiant transition via three-body ultrastrong coupling [62.997667081978825]
  We introduce a class of quantum optical Hamiltonian characterized by three-body couplings. We propose a circuit-QED scheme based on state-of-the-art technology that implements the considered model.
  arXiv  Detail & Related papers  (2022-04-07T15:39:21Z)
• 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)

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.