Entangling power and fidelity diagnostic for bipartite quantum channels

• URL: http://arxiv.org/abs/2605.26867v2
• Date: Mon, 01 Jun 2026 11:45:39 GMT
• Title: Entangling power and fidelity diagnostic for bipartite quantum channels
• Abstract summary: We show that the fidelity averaged over any fixed Schmidt-coefficients local-unitary orbit for equal local dimensions is completely determined by average input-output fidelity and its restriction to product inputs.<n>We also introduce concurrence- and negativity-based entangling power for 2-qubit channels, prove their convexity and monotonicity under local postprocessing, and show that, unlike the previously proposed linear-entropy quantity, they vanish for all separable channels.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We study two complementary diagnostics of bipartite quantum channels, namely fidelity preservation across different classes of input states and entanglement generation from product inputs, given by properly defined entangling power for bipartite channels. We show that the fidelity averaged over any fixed Schmidt-coefficients local-unitary orbit for equal local dimensions is completely determined by average input-output fidelity and its restriction to product inputs. We also introduce concurrence- and negativity-based entangling power for 2-qubit channels, prove their convexity and monotonicity under local postprocessing, and show that, unlike the previously proposed linear-entropy quantity, they vanish for all separable channels. Examples of non-separable channels are investigated. Finally, we generalize our definitions of entangling power to non-product inputs, and provide an analytical lower bound for the concurrence-based entanglement variation, showing its effectiveness with specific examples.

Related papers

• Entangling capability of coherently controlled quantum processes [0.0]
  We analytically characterize entanglement generation by two paradigmatic coherently controlled quantum processes, the quantum switch and time-flip.<n>For the switch of qubit unitaries, we derive exact expressions for entanglement, together with a geometric characterization and a coherence-entanglement conservation relation.<n>We prove that switch of channels commuting under composition cannot entangle a separable input. Yet maximal entanglement is possible even with dissipation.
  arXiv  Detail & Related papers  (2026-08-31T18:01:03Z)
• Quantifying Coherence-to-Entanglement Conversion Efficiency under Noisy Operations [0.9051352746190449]
  We investigate the noise-limited conversion of local quantum coherence into bipartite entanglement in a minimal two-qubit protocol.<n>We show that maximally coherent inputs not only maximize the entanglement generated by the CNOT protocol but also optimize its robustness against depolarizing noise.
  arXiv  Detail & Related papers  (2026-06-15T16:23:27Z)
• Characterizing quantum channels from local-unitary invariants [0.0]
  We introduce averaged local-unitary invariants, referred to as moments, obtained from Haar integrals over input states or unitaries.<n>These moments provide computable descriptions of how a quantum channel can create, preserve, or destroy bipartite entanglement.
  arXiv  Detail & Related papers  (2026-06-02T14:42:14Z)
• Entanglement cost of bipartite quantum channel discrimination under positive partial transpose operations [7.065586557684262]
  We study the class of $k$-injectable positive-partial-transpose (PPT) testers, which constitutes a numerically tractable relaxation of the practically relevant class of LOCC testers.<n>For every $k$, we derive a semidefinite program (SDP) for the optimal success probability, which in turn yields an efficiently computable one-shot entanglement cost.
  arXiv  Detail & Related papers  (2026-03-12T16:31:33Z)
• Entanglement Fidelity in Standard Quantum Channels [7.792020418343022]
  Entanglement fidelity quantifies how well a quantum channel preserves the correlations between a transmitted system and an inaccessible reference system.<n>We derive closed-form expressions for the entanglement fidelity associated with several standard quantum noise models.
  arXiv  Detail & Related papers  (2026-03-08T18:50:15Z)
• Convergence Properties of Good Quantum Codes for Classical Communication [46.17112353277822]
  We show the uniqueness of the optimal output distribution, to be able to talk more concretely about the optimal output distribution.<n>We extend the vanishing error probability results to the quantum case, by using techniques that are close in spirit to the classical case.
  arXiv  Detail & Related papers  (2026-01-16T18:22:05Z)
• Optimizing entanglement distribution via noisy quantum channels [44.99833362998488]
  Entanglement distribution is a crucial problem in quantum information science.<n>We investigate strategies for distributing quantum entanglement between two distant parties through noisy quantum channels.
  arXiv  Detail & Related papers  (2025-06-06T13:48:20Z)
• Resolvability of classical-quantum channels [54.825573549226924]
  We study the resolvability of classical-quantum channels in two settings, for the channel output generated from the worst input, and form the fixed independent and identically distributed (i.i.d.) input. For the fixed-input setting, while the direct part follows from the known quantum soft covering result, we exploit the recent alternative quantum Sanov theorem to solve the strong converse.
  arXiv  Detail & Related papers  (2024-10-22T05:18:43Z)
• Certifying nonlocal properties of noisy quantum operations [0.0]
  Certifying quantum properties from the probability distributions they induce is an important task for several purposes.<n>In particular, little is known about to what extent noise can spoil certification methods for channels.<n>We provide a unified methodology to certify nonlocal properties of quantum channels from the correlations obtained in prepare-and-measurement protocols.
  arXiv  Detail & Related papers  (2024-07-02T18:00:06Z)
• Deterministic identification over channels with finite output: a dimensional perspective on superlinear rates [49.126395046088014]
  We consider the problem in its generality for memoryless channels with finite output, but arbitrary input alphabets.<n>Our main findings are that the maximum length of messages thus identifiable scales superlinearly as $R,nlog n$ with the block length $n$.<n>We show that it is sufficient to ensure pairwise reliable distinguishability of the output distributions to construct a DI code.
  arXiv  Detail & Related papers  (2024-02-14T11:59:30Z)
• A Lie Algebraic Theory of Barren Plateaus for Deep Parameterized Quantum Circuits [37.84307089310829]
  Variational quantum computing schemes train a loss function by sending an initial state through a parametrized quantum circuit. Despite their promise, the trainability of these algorithms is hindered by barren plateaus. We present a general Lie algebra that provides an exact expression for the variance of the loss function of sufficiently deep parametrized quantum circuits.
  arXiv  Detail & Related papers  (2023-09-17T18:14:10Z)
• Normal quantum channels and Markovian correlated two-qubit quantum errors [77.34726150561087]
  We study general normally'' distributed random unitary transformations. On the one hand, a normal distribution induces a unital quantum channel. On the other hand, the diffusive random walk defines a unital quantum process.
  arXiv  Detail & Related papers  (2023-07-25T15:33:28Z)
• Correlation measures of a quantum state and information characteristics of a quantum channel [0.0]
  We discuss the interconnections between basic correlation measures of a bipartite quantum state and basic information characteristics of a quantum channel. We describe properties of the (unoptimized and optimized) quantum discord in infinite bipartite systems.
  arXiv  Detail & Related papers  (2023-04-11T17:58:13Z)
• Numerical estimation of reachable and controllability sets for a two-level open quantum system driven by coherent and incoherent controls [77.34726150561087]
  The article considers a two-level open quantum system governed by the Gorini--Kossakowski--Lindblad--Sudarshan master equation. The system is analyzed using Bloch parametrization of the system's density matrix.
  arXiv  Detail & Related papers  (2021-06-18T14:23:29Z)
• Usefulness of adaptive strategies in asymptotic quantum channel discrimination [43.7637825272776]
  We investigate the usefulness of adaptive methods in the framework of binary hypothesis testing. There is a fundamental distinction between adaptive and non-adaptive strategies with respect to the channel uses. We show that adaptive strategies with classical feedback do not increase the discrimination power of the channel beyond non-adaptive product input strategies.
  arXiv  Detail & Related papers  (2020-11-12T18:40:47Z)

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.