Extracting the physical sector of quantum states

Mogilevtsev, D.; Teo, Yong Siah; Řeháček, J.; Hradil, Z.; Tiedau, Johannes; Kruse, Regina; Harder, Georg; Silberhorn, Christine; Sánchez-Soto, Luis L.

doi:10.1088/1367-2630/aa81b3

Cited by 4 publications

(2 citation statements)

References 35 publications

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“…We then use the theoretical results of [42] to formulate coherence and dimension witnesses for the case of three states produced by a physical single-photon source. We show that for especially prepared polarization states, our pooled HOM measurements can be used to witness quantum coherence in a basis-independent way, in contrast with basisdependent witnesses proposed previously, e.g., in [3][4][5]50]. For this, we tuned the two-photon indistinguishabilities to suitable, intermediate values, which are provably unreachable by coherence-free, diagonal states in any single basis.…”

Section: Introductionmentioning

confidence: 81%

Witnesses of coherence and dimension from multiphoton indistinguishability tests

Giordani

Esposito

Hoch

et al. 2021

Conference on Lasers and Electro-Optics

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Quantum coherence marks a deviation from classical physics, and has been studied as a resource for metrology and quantum computation. Finding reliable and effective methods for assessing its presence is then highly desirable. Coherence witnesses rely on measuring observables whose outcomes can guarantee that a state is not diagonal in a known reference basis. Here, we experimentally measure a type of coherence witness that uses pairwise state comparisons to identify superpositions in a basis-independent way. Our experiment uses a single interferometric setup to simultaneously measure the three pairwise overlaps among three single-photon states via Hong-Ou-Mandel tests. Aside from coherence witnesses, we show the measurements also serve as a Hilbert-space dimension witness. Our results attest to the effectiveness of pooling many two-state comparison tests to ascertain various relational properties of a set of quantum states.

show abstract

Section: Introductionmentioning

confidence: 81%

Witnesses of coherence and dimension from multiphoton indistinguishability tests

Giordani

Esposito

Hoch

et al. 2021

Conference on Lasers and Electro-Optics

View full text Add to dashboard Cite

show abstract

“…We show that for especially prepared polarization states, our pooled HOM measurements can be used to witness quantum coherence in a basisindependent way, in contrast with basis-dependent witnesses proposed previously, e.g. in [3][4][5]50]. For this, we tuned the two-photon indistinguishabilities to suitable, intermediate values, which are provably unreachable by coherence-free, diagonal states in any single basis.…”

Section: Introductionmentioning

confidence: 82%

Witnesses of coherence and dimension from multiphoton indistinguishability tests

Giordani,

Esposito,

Hoch

et al. 2021

Preprint

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Quantum coherence marks a deviation from classical physics, and has been studied as a resource for metrology and quantum computation. Finding reliable and effective methods for assessing its presence is then highly desirable. Coherence witnesses rely on measuring observables whose outcomes can guarantee that a state is not diagonal in a known reference basis. Here we experimentally measure a novel type of coherence witness that uses pairwise state comparisons to identify superpositions in a basis-independent way. Our experiment uses a single interferometric set-up to simultaneously measure the three pairwise overlaps among three single-photon states via Hong-Ou-Mandel tests. Besides coherence witnesses, we show the measurements also serve as a Hilbert-space dimension witness. Our results attest to the effectiveness of pooling many two-state comparison tests to ascertain various relational properties of a set of quantum states.

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Evidence-Based Certification of Quantum Dimensions

Teo,

Shringarpure,

Jeong

et al. 2024

Phys. Rev. Lett.

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Identifying a reasonably small Hilbert space that completely describes an unknown quantum state is crucial for efficient quantum information processing. We introduce a general dimension-certification protocol for both discrete and continuous variables that is fully evidence based, relying solely on the experimental data collected and no other unjustified assumptions whatsoever. Using the Bayesian concept of relative belief, we take the effective dimension of the state as the smallest one such that the posterior probability is larger than the prior, as dictated by the data. The posterior probabilities associated with the relative-belief ratios measure the strength of the evidence provide by these ratios so that we can assess whether there is weak or strong evidence in favor or against a particular dimension. Using experimental data from spectral-temporal and polarimetry measurements, we demonstrate how to correctly assign Bayesian plausible error bars for the obtained effective dimensions. This makes relative belief a conservative and easy-to-use model-selection method for any experiment. Published by the American Physical Society 2024

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Extracting the physical sector of quantum states

Cited by 4 publications

References 35 publications

Witnesses of coherence and dimension from multiphoton indistinguishability tests

Witnesses of coherence and dimension from multiphoton indistinguishability tests

Witnesses of coherence and dimension from multiphoton indistinguishability tests

Evidence-Based Certification of Quantum Dimensions

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