Assessing the performance of quantum repeaters for all phase-insensitive Gaussian bosonic channels
One of the most sought-after goals in experimental quantum communication is the implementation of a quantum repeater. The performance of quantum repeaters can be assessed by comparing the attained rate with the quantum and private capacity of direct transmission, assisted by unlimited classical two-...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2016-01-01
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| Series: | New Journal of Physics |
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| Online Access: | https://doi.org/10.1088/1367-2630/18/6/063005 |
| _version_ | 1797750982941081600 |
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| author | K Goodenough D Elkouss S Wehner |
| author_facet | K Goodenough D Elkouss S Wehner |
| author_sort | K Goodenough |
| collection | DOAJ |
| description | One of the most sought-after goals in experimental quantum communication is the implementation of a quantum repeater. The performance of quantum repeaters can be assessed by comparing the attained rate with the quantum and private capacity of direct transmission, assisted by unlimited classical two-way communication. However, these quantities are hard to compute, motivating the search for upper bounds. Takeoka, Guha and Wilde found the squashed entanglement of a quantum channel to be an upper bound on both these capacities. In general it is still hard to find the exact value of the squashed entanglement of a quantum channel, but clever sub-optimal squashing channels allow one to upper bound this quantity, and thus also the corresponding capacities. Here, we exploit this idea to obtain bounds for any phase-insensitive Gaussian bosonic channel. This bound allows one to benchmark the implementation of quantum repeaters for a large class of channels used to model communication across fibers. In particular, our bound is applicable to the realistic scenario when there is a restriction on the mean photon number on the input. Furthermore, we show that the squashed entanglement of a channel is convex in the set of channels, and we use a connection between the squashed entanglement of a quantum channel and its entanglement assisted classical capacity. Building on this connection, we obtain the exact squashed entanglement and two-way assisted capacities of the d -dimensional erasure channel and bounds on the amplitude-damping channel and all qubit Pauli channels. In particular, our bound improves on the previous best known squashed entanglement upper bound of the depolarizing channel. |
| first_indexed | 2024-03-12T16:40:45Z |
| format | Article |
| id | doaj.art-b2f4a59bd1c342dc98ac46f45b322938 |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:40:45Z |
| publishDate | 2016-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-b2f4a59bd1c342dc98ac46f45b3229382023-08-08T14:31:45ZengIOP PublishingNew Journal of Physics1367-26302016-01-0118606300510.1088/1367-2630/18/6/063005Assessing the performance of quantum repeaters for all phase-insensitive Gaussian bosonic channelsK Goodenough0D Elkouss1https://orcid.org/0000-0003-2023-2768S Wehner2QuTech, Delft University of Technology , Lorentzweg 1, 2628 CJ Delft, The NetherlandsQuTech, Delft University of Technology , Lorentzweg 1, 2628 CJ Delft, The NetherlandsQuTech, Delft University of Technology , Lorentzweg 1, 2628 CJ Delft, The NetherlandsOne of the most sought-after goals in experimental quantum communication is the implementation of a quantum repeater. The performance of quantum repeaters can be assessed by comparing the attained rate with the quantum and private capacity of direct transmission, assisted by unlimited classical two-way communication. However, these quantities are hard to compute, motivating the search for upper bounds. Takeoka, Guha and Wilde found the squashed entanglement of a quantum channel to be an upper bound on both these capacities. In general it is still hard to find the exact value of the squashed entanglement of a quantum channel, but clever sub-optimal squashing channels allow one to upper bound this quantity, and thus also the corresponding capacities. Here, we exploit this idea to obtain bounds for any phase-insensitive Gaussian bosonic channel. This bound allows one to benchmark the implementation of quantum repeaters for a large class of channels used to model communication across fibers. In particular, our bound is applicable to the realistic scenario when there is a restriction on the mean photon number on the input. Furthermore, we show that the squashed entanglement of a channel is convex in the set of channels, and we use a connection between the squashed entanglement of a quantum channel and its entanglement assisted classical capacity. Building on this connection, we obtain the exact squashed entanglement and two-way assisted capacities of the d -dimensional erasure channel and bounds on the amplitude-damping channel and all qubit Pauli channels. In particular, our bound improves on the previous best known squashed entanglement upper bound of the depolarizing channel.https://doi.org/10.1088/1367-2630/18/6/063005quantum informationquantum repeatersquantum communicationsecret key ratequantum key distributionsquashed entanglement |
| spellingShingle | K Goodenough D Elkouss S Wehner Assessing the performance of quantum repeaters for all phase-insensitive Gaussian bosonic channels New Journal of Physics quantum information quantum repeaters quantum communication secret key rate quantum key distribution squashed entanglement |
| title | Assessing the performance of quantum repeaters for all phase-insensitive Gaussian bosonic channels |
| title_full | Assessing the performance of quantum repeaters for all phase-insensitive Gaussian bosonic channels |
| title_fullStr | Assessing the performance of quantum repeaters for all phase-insensitive Gaussian bosonic channels |
| title_full_unstemmed | Assessing the performance of quantum repeaters for all phase-insensitive Gaussian bosonic channels |
| title_short | Assessing the performance of quantum repeaters for all phase-insensitive Gaussian bosonic channels |
| title_sort | assessing the performance of quantum repeaters for all phase insensitive gaussian bosonic channels |
| topic | quantum information quantum repeaters quantum communication secret key rate quantum key distribution squashed entanglement |
| url | https://doi.org/10.1088/1367-2630/18/6/063005 |
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