Tomographic entanglement indicators in multipartite systems

Sharmila, B.; Lakshmibala, S.; Balakrishnan, V.

doi:10.1007/s11128-020-02625-5

Cited by 8 publications

(7 citation statements)

References 21 publications

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“…In this section, we extend our analysis of the nonclassical area given in section 3 and introduce an indicator of nonclassicality for a two-mode state of the electromagnetic field. The optical tomogram of several two-mode states was theoretically calculated using equation ( 9) [30,44]. Since the homodyne rotated quadrature operator X θ1,θ2 (see (8)) is in a separable form, and it obeys the uncertainty relation, it is straightforward to extend our analysis using the uncertainty relation for the case of a two-mode field.…”

Section: Nonclassical Area For a Two-mode Fieldmentioning

confidence: 99%

Homodyne nonclassical area as a nonclassicality indicator

Rohith¹,

Kannan²,

Sudheesh³

2023

J. Phys. B: At. Mol. Opt. Phys.

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We propose a legitimate and easily computable nonclassicality indicator for the states of electromagnetic field based on the standard deviation in the measurement of the homodyne rotated quadrature operator. The proposed nonclassicality indicator is the nonclassical area projected by the optical tomogram of the quantum state of light on the optical tomographic plane. If the nonclassical area projected by the optical tomogram of a quantum state is greater than zero, the state is nonclassical, and the area is zero for the pure classical state. It is also noted that the nonclassical area of a quantum state increases with an increase in the strength of nonclassicality inducing operations on the state such as the squeezing, photon addition, etc. We have tested the validity of the nonclassical area measure by calculating the same for certain well-known nonclassical states and found that essential features of the nonclassicality shown by the states are captured in the nonclassical area. We have also shown that the nonclassical area is robust against environment-induced decoherence of the states. Nonclassical area projected by the optical tomogram of a quantum state of light is experimentally tractable using the balanced homodyne detection of the quadrature operator of the field, avoiding the reconstruction of the density matrix or the quasiprobability distribution of the state.

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Section: Nonclassical Area For a Two-mode Fieldmentioning

confidence: 99%

Homodyne nonclassical area as a nonclassicality indicator

Rohith¹,

Kannan²,

Sudheesh³

2023

J. Phys. B: At. Mol. Opt. Phys.

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“…Further, a detailed analysis of entanglement has been carried out theoretically using several indicators obtained directly from tomograms in different contexts, e.g., close to avoided energy-level crossings [6]. The efficacy of such indicators has been assessed by comparison with standard entanglement measures [7,8]. Further, these indicators have also been examined using the IBM quantum computing platform, by translating certain multipartite hybrid quantum systems into suitable equivalent circuits [9].…”

Section: Introductionmentioning

confidence: 99%

“…The efficacy of such indicators has been assessed by comparison with standard entanglement measures [7,8]. Further, these indicators have also been examined using the IBM quantum computing platform, by translating certain multipartite hybrid quantum systems into suitable equivalent circuits [9]. It is to be noted that, in these examples, measurements of multiple observables corresponding to the rotated quadrature operators…”

Section: Introductionmentioning

confidence: 99%

Tomographic entanglement indicators in frequency combs and Talbot carpets

Sharmila

Lakshmibala

Balakrishnan

2022

J. Phys. B: At. Mol. Opt. Phys.

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Recent theoretical investigations on tomographic entanglement indicators have showcased the advantages of the tomographic approach in the context of continuous-variable (CV), spin and hybrid quantum systems. Direct estimation of entanglement using experimental data from the IBM quantum computing platform and NMR experiments has also been carried out in earlier work. A similar investigation in the context of CV systems is necessary to assess fully the utility of the tomographic approach. In this paper, we highlight the advantages of this approach in the context of experiments reported in the literature on two CV systems, namely, entangled Talbot carpets and entangled biphoton frequency combs. We use the tomographic entanglement indicator to estimate the degree of entanglement between a pair of Talbot carpets, and demonstrate that this provides a simpler and more direct procedure as compared to the one suggested in the experiment. We also establish that the tomograms corresponding to two biphoton frequency combs carry clear entanglement signatures that distinguish between the two states.

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“…Their efficacy has been assessed by comparison with standard entanglement measures [7,8]. Further, these indicators have been examined using the IBM quantum computing platform by translating certain multipartite hybrid quantum (HQ) systems into suitable equivalent circuits [9]. It is to be noted that in these examples, measurements of multiple observables corresponding to the rotated quadrature operators…”

Section: Introductionmentioning

confidence: 99%

Tomographic entanglement indicators in frequency combs and Talbot carpets

Sharmila,

Lakshmibala,

Balakrishnan

2021

Preprint

Self Cite

View full text Add to dashboard Cite

Recent theoretical investigations on tomographic entanglement indicators have showcased the advantages of the tomographic approach in the context of continuous-variable (CV), spin and hybrid quantum systems. Direct estimation of entanglement using experimental data from the IBM quantum computing platform and NMR experiments have also been carried out in earlier work. A similar investigation in the context of CV systems is necessary to fully assess the utility of our tomographic approach. In this paper, we highlight the advantages of our approach in the context of experiments reported in the literature on two CV systems, namely, entangled Talbot carpets and biphoton frequency combs. We use the tomographic entanglement indicator to assess the extent of entanglement between a pair of Talbot carpets and demonstrate that this provides a simpler and more direct procedure compared to the one suggested in the experiment. We also establish that the tomograms corresponding to the two biphoton frequency combs carry clear entanglement signatures that distinguish between the two states.

show abstract

Tomographic entanglement indicators in multipartite systems

Cited by 8 publications

References 21 publications

Homodyne nonclassical area as a nonclassicality indicator

Homodyne nonclassical area as a nonclassicality indicator

Tomographic entanglement indicators in frequency combs and Talbot carpets

Tomographic entanglement indicators in frequency combs and Talbot carpets

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