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arxiv: 2605.23232 · v1 · pith:ZCRQ3KYQnew · submitted 2026-05-22 · 🪐 quant-ph · cond-mat.mes-hall· cond-mat.str-el

Interference of local-measurement histories

Parveen Kumar , Igor V. Gornyi , Yuval Gefen This is my paper

Pith reviewed 2026-05-25 04:46 UTC · model grok-4.3

classification 🪐 quant-ph cond-mat.mes-hallcond-mat.str-el
keywords interference of historieslocal measurementsentanglementqubitsmeasurement-driven dynamicscoherent controlquantum correlations
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The pith

Two local measurement histories on qubits can interfere to generate entanglement between them.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper seeks to establish that histories composed of local measurements are capable of interfering with one another when placed under coherent control. This interference appears as entanglement between two qubits that interact only with separate detectors. Even when the outcomes recorded by those detectors are averaged, the resulting two-qubit state remains entangled, although not maximally so. A reader would care because the result treats measurements as active participants in building quantum correlations rather than solely as destroyers of coherence.

Core claim

We develop a protocol in which two alternative local measurement processes act on a pair of qubits, and show how interference of histories is generated under coherent control, leading to entanglement. Furthermore, we find that averaging over the detectors' readouts still results in an entangled (albeit not maximally entangled) state. Our results extend the notion of quantum interference beyond unitary evolution to genuinely measurement-driven dynamics.

What carries the argument

Protocol that applies coherent control to superpose or switch between two distinct local measurement processes on a pair of qubits.

If this is right

  • Entanglement is generated between two parts of the system that are each coupled only to its own detector.
  • Averaging over the detectors' readouts produces an entangled though not maximally entangled state.
  • Quantum interference extends to dynamics driven by local measurements.
  • Limits exist on the generation of quantum correlations through interference of measurement histories.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The mechanism offers a route to entanglement in systems lacking direct qubit-qubit coupling.
  • Controlled measurement sequences could be used to engineer specific entangled states in architectures where unitary gates are costly.
  • The same interference may appear in multi-detector setups, producing measurable correlations that survive partial averaging.

Load-bearing premise

Coherent control can be applied to switch between or superpose two distinct local measurement processes without additional decoherence or back-action that destroys the interference.

What would settle it

An experiment on two qubits that applies the coherent-control protocol, records the detectors, and finds the averaged final state to be separable would falsify the claim that measurement-history interference produces entanglement.

Figures

Figures reproduced from arXiv: 2605.23232 by Igor V. Gornyi, Parveen Kumar, Yuval Gefen.

Figure 1
Figure 1. Figure 1: Coherently controlled measurement histories. The [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Concurrence Cavg(g, θ) [cf. Eq. (16)] of the readout￾averaged state for the two-qubit example, as a function of measurement strength g and angle θ. The solid white curve denotes the CHSH Bell-nonlocality boundary γ(g, θ) = 1, ob￾tained from the Horodecki criterion for two-qubit states [58]. The figure shows two distinct regimes: an entangled but Bell￾local region (γ ≤ 1) and a Bell-nonlocal region (γ > 1),… view at source ↗
read the original abstract

The evolution of a quantum system comprises two fundamental processes--continuous unitary dynamics and stochastic measurement-induced jumps. The latter are often viewed as a source of decoherence. Can two histories of such an evolution, made up of local measurements, interfere with each other? Here, we answer this question in the affirmative. A manifestation of this interference is the generation of entanglement between two parts of the system that are individually coupled to distinct detectors. Specifically, we develop a protocol in which two alternative local measurement processes act on a pair of qubits, and show how interference of histories is generated under coherent control, leading to entanglement. Furthermore, we find that averaging over the detectors' readouts still results in an entangled (albeit not maximally entangled) state. Our results extend the notion of quantum interference beyond unitary evolution to genuinely measurement-driven dynamics, and identify limits on the generation of quantum correlations using interference of measurement histories.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 0 minor

Summary. The manuscript develops a protocol in which two alternative local measurement processes act on a pair of qubits under coherent control. It claims that interference between the resulting measurement histories generates entanglement between the qubits, and that this entanglement persists (though not maximally) in the unconditional state obtained by averaging over the detectors' readouts. The work positions this as an extension of quantum interference to genuinely measurement-driven dynamics.

Significance. If the central claims hold, the result would demonstrate that measurement histories can interfere coherently in a manner that produces quantum correlations even after unconditional averaging, with potential relevance to quantum control and foundations. No machine-checked proofs or parameter-free derivations are reported.

major comments (1)
  1. [Abstract / protocol and results sections] The claim that averaging over detectors' readouts yields an entangled state (abstract) is load-bearing for the central result. The manuscript must explicitly compute the unconditional reduced density matrix of the two qubits and demonstrate that the cross terms from the coherent superposition of histories produce a non-separable operator (e.g., via negative eigenvalues of the partial transpose). Without this calculation, it remains unclear whether the interference survives the trace over readouts or whether the state factorizes as expected for a mixture of distinct histories.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their careful reading and for identifying the need for an explicit demonstration of the unconditional state. We address the major comment below and will revise the manuscript to incorporate the requested calculation.

read point-by-point responses

  1. Referee: [Abstract / protocol and results sections] The claim that averaging over detectors' readouts yields an entangled state (abstract) is load-bearing for the central result. The manuscript must explicitly compute the unconditional reduced density matrix of the two qubits and demonstrate that the cross terms from the coherent superposition of histories produce a non-separable operator (e.g., via negative eigenvalues of the partial transpose). Without this calculation, it remains unclear whether the interference survives the trace over readouts or whether the state factorizes as expected for a mixture of distinct histories.

    Authors: We agree that an explicit computation is required to substantiate the claim. The original manuscript states the result in the abstract and derives the conditional states under coherent control, but the unconditional reduced density matrix (obtained by tracing over detector readouts) was not displayed with full matrix elements or partial-transpose eigenvalues. In the revised manuscript we will add this calculation in the results section: we will write the two-qubit state as a coherent superposition of the two measurement histories, trace out the detector degrees of freedom, retain the cross terms generated by the coherent control, and verify that the resulting operator has at least one negative eigenvalue under partial transposition. This will confirm that the interference survives averaging and produces a non-separable state. revision: yes

Circularity Check

0 steps flagged

No circularity; abstract and claims self-contained with no equations or self-referential reductions visible

full rationale

The abstract describes a protocol for interference of local measurement histories leading to entanglement, including after averaging over readouts, but provides no equations, derivations, fitted parameters, or self-citations. Without any load-bearing steps, ansatzes, or uniqueness theorems quoted from the paper itself, no reduction to inputs by construction can be exhibited. This is the default honest non-finding when the provided text contains no mathematical chain to inspect.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Abstract only; no free parameters, axioms, or invented entities are described.

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Reference graph

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    General framework Here we present a microscopic model that generates the coherently controlled local measurement dynamics described in the main text. The total Hilbert space is H=H C ⊗ HA ⊗ HB ⊗ HDA ⊗ HDB ,(A1) whereH C corresponds to the control qubit,HA,B to the system qubits, andH DA,DB to detector qubits locally coupled toAandB. The initial joint stat...

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    A1 to the two–qubit example discussed in the main text

    Microscopic model for the canonical example of the main text Wenowspecializethegeneralmicroscopicconstruction of Sec. A1 to the two–qubit example discussed in the main text. Our goal is to realize the Kraus operators (4) L±(g,ˆn) =aΠ ±(ˆn) +bΠ∓(ˆn),(A10) with a= r 1 +g 2 ,andb= r 1−g 2 .(A11) Here,Π ±(ˆn)are projectors onto eigenstates ofσˆn= ˆn·⃗ σ andg∈...

    work page