Randomness in post-selected events
Bell inequality violations can be used to certify private randomness for use in cryptographic applications. In photonic Bell experiments, a large amount of the data that is generated comes from no-detection events and presumably contains little randomness. This raises the question as to whether rand...
| 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 |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1367-2630/18/3/035007 |
| _version_ | 1797750999128997888 |
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| author | Le Phuc Thinh Gonzalo de la Torre Jean-Daniel Bancal Stefano Pironio Valerio Scarani |
| author_facet | Le Phuc Thinh Gonzalo de la Torre Jean-Daniel Bancal Stefano Pironio Valerio Scarani |
| author_sort | Le Phuc Thinh |
| collection | DOAJ |
| description | Bell inequality violations can be used to certify private randomness for use in cryptographic applications. In photonic Bell experiments, a large amount of the data that is generated comes from no-detection events and presumably contains little randomness. This raises the question as to whether randomness can be extracted only from the smaller post-selected subset corresponding to proper detection events, instead of from the entire set of data. This could in principle be feasible without opening an analogue of the detection loophole as long as the min-entropy of the post-selected data is evaluated by taking all the information into account, including no-detection events. The possibility of extracting randomness from a short string has a practical advantage, because it reduces the computational time of the extraction. Here, we investigate the above idea in a simple scenario, where the devices and the adversary behave according to i.i.d. strategies. We show that indeed almost all the randomness is present in the pair of outcomes for which at least one detection happened. We further show that in some cases applying a pre-processing on the data can capture features that an analysis based on global frequencies only misses, thus resulting in the certification of more randomness. We then briefly consider non-i.i.d strategies and provide an explicit example of such a strategy that is more powerful than any i.i.d. one even in the asymptotic limit of infinitely many measurement rounds, something that was not reported before in the context of Bell inequalities. |
| first_indexed | 2024-03-12T16:42:00Z |
| format | Article |
| id | doaj.art-eb683df1e88b4acba881da1bfaee8f96 |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:42:00Z |
| publishDate | 2016-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-eb683df1e88b4acba881da1bfaee8f962023-08-08T14:30:06ZengIOP PublishingNew Journal of Physics1367-26302016-01-0118303500710.1088/1367-2630/18/3/035007Randomness in post-selected eventsLe Phuc Thinh0Gonzalo de la Torre1Jean-Daniel Bancal2Stefano Pironio3Valerio Scarani4Centre for Quantum Technologies, National University of Singapore , 3 Science Drive 2, Singapore 117543ICFO-Institute of Photonic Sciences, Mediterranean Technology Park, E-08860 Castelldefels (Barcelona), SpainCentre for Quantum Technologies, National University of Singapore , 3 Science Drive 2, Singapore 117543Laboratoire d’Information Quantique, Université Libre de Bruxelles (ULB) , Brussels, BelgiumCentre for Quantum Technologies, National University of Singapore , 3 Science Drive 2, Singapore 117543; Department of Physics, National University of Singapore , 2 Science Drive 3, 117542 SingaporeBell inequality violations can be used to certify private randomness for use in cryptographic applications. In photonic Bell experiments, a large amount of the data that is generated comes from no-detection events and presumably contains little randomness. This raises the question as to whether randomness can be extracted only from the smaller post-selected subset corresponding to proper detection events, instead of from the entire set of data. This could in principle be feasible without opening an analogue of the detection loophole as long as the min-entropy of the post-selected data is evaluated by taking all the information into account, including no-detection events. The possibility of extracting randomness from a short string has a practical advantage, because it reduces the computational time of the extraction. Here, we investigate the above idea in a simple scenario, where the devices and the adversary behave according to i.i.d. strategies. We show that indeed almost all the randomness is present in the pair of outcomes for which at least one detection happened. We further show that in some cases applying a pre-processing on the data can capture features that an analysis based on global frequencies only misses, thus resulting in the certification of more randomness. We then briefly consider non-i.i.d strategies and provide an explicit example of such a strategy that is more powerful than any i.i.d. one even in the asymptotic limit of infinitely many measurement rounds, something that was not reported before in the context of Bell inequalities.https://doi.org/10.1088/1367-2630/18/3/035007quantum randomnessdevice independentBell testsdetection loopholepost-selection |
| spellingShingle | Le Phuc Thinh Gonzalo de la Torre Jean-Daniel Bancal Stefano Pironio Valerio Scarani Randomness in post-selected events New Journal of Physics quantum randomness device independent Bell tests detection loophole post-selection |
| title | Randomness in post-selected events |
| title_full | Randomness in post-selected events |
| title_fullStr | Randomness in post-selected events |
| title_full_unstemmed | Randomness in post-selected events |
| title_short | Randomness in post-selected events |
| title_sort | randomness in post selected events |
| topic | quantum randomness device independent Bell tests detection loophole post-selection |
| url | https://doi.org/10.1088/1367-2630/18/3/035007 |
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