Pith. sign in

REVIEW 4 cited by

Direct estimations of linear and non-linear functionals of a quantum state

Not yet reviewed by Pith; the record is open.

This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.

SPECIMEN: schema-true, not a live event

T0 review · schema-true

One-sentence machine reading of the paper's core claim.

pith:XXXXXXXX · record.json · timestamp

arxiv quant-ph/0203016 v1 pith:WRCL5MSG submitted 2002-03-04 quant-ph

classification quant-ph
keywords quantumdirectestimationsnetworkfunctionalslinearnon-linearproperties
verification ladder T0 review T1 audit T2 compute T3 formal

Signed reviews

No signed human review yet.

0 comments
read the original abstract

We present a simple quantum network, based on the controlled-SWAP gate, that can extract certain properties of quantum states without recourse to quantum tomography. It can be used used as a basic building block for direct quantum estimations of both linear and non-linear functionals of any density operator. The network has many potential applications ranging from purity tests and eigenvalue estimations to direct characterization of some properties of quantum channels. Experimental realizations of the proposed network are within the reach of quantum technology that is currently being developed.

Discussion (0). Continue with ORCID to comment.

Forward citations

Cited by 4 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. An Optimal Analysis of the Product Test

    quant-ph 2026-07 accept novelty 7.0 of 10

    For every n >= 2, the product test's worst-case acceptance probability equals (1 + mω^2 + (1−mω)^2)/2 with m = floor(1/ω), where ω is the maximum squared overlap with a product state.

  2. On estimating operator norm distance, with optimal trace distance estimation when one state is pure

    quant-ph 2026-07 accept novelty 7.0 of 10

    Rank-independent quantum estimators achieve Θ(1/ε) queries for operator-norm (and trace) distance when one state is pure, and Õ(1/ε^{3/2}) queries for general states, proving BQP-completeness.

  3. Imaginary pseudo entropy encodes temporal orientation

    quant-ph 2026-06 unverdicted novelty 7.0 of 10

    The calibrated pseudo-Rényi phase and replica visibility exactly equal the Helstrom trace distance between forward and backward ancilla states, giving a bounded operational meaning to imaginary pseudo entropy.

  4. On estimating Schatten norm and power distances between quantum states

    quant-ph 2025-05 conditional novelty 7.0 of 10

    For constant alpha > 1, the quantum Schatten alpha-norm distance between states given by preparation circuits can be estimated in polynomial time, and the corresponding decision problem QSD_alpha is BQP-complete; for ...

Pith tools