asymptotic security proof for discrete- modulated cvqkd … · p bob parameter estimation q p q p...
TRANSCRIPT
Uniform Continuity of Conditional EntropyW can be determined from parameter estimation, and characterizes the weight outside the finite subspace.Using a generalization of the result in [5], we have: 1�W F (P,Q) =) |f(P )� f(Q)| ✏N (W )
<latexit sha1_base64="0pdyLye3XXVjyebchOk2h+SCHug=">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</latexit>
Main Theorem
Asymptotic Security Proof for Discrete-Modulated CVQKD without Cutoff Assumption
Twesh Upadhyaya | Thomas van Himbeeck | Jie Lin | Norbert Lütkenhaus
IntroductionGoal is to compute tight key rates for DMCVQKD with a small number of modulated states.
Want to harness the existing numerics framework for finite-dimensional optimizations [1][2].
Previous work assumes the state is finite-dimensional; the cutoffassumption. This gives numerically stable results but is not a rigorous security proof [3].
Our ContributionWe establish the asymptotic security of DMCVQKD with a small number of modulated states. In particular, we do not use a cutoff assumption.
We develop a framework to provide tight, reliable key rates for other protocols with infinite-dimensional Hilbert spaces.
Key Rate FormulaUnder collective attacks in the asymptotic limit, given by Devetak-Winter formula [4]:
Evaluated on worst-case state compatible with statistics from parameter estimation; after post-processing.
Reformulate:
If ɸ is the CPTNI map representing the post-processing performed by Alice and Bob, then:
R = min⇢2S
[H(X|E)]�H(X) + I(A : B)
<latexit sha1_base64="xft7MNyGOb/h28rbA6hJx7caOW4=">AAACLnicbVDLSgMxFM3UV62vqks3wSK0iGVGKoog1IpQd/XRB3SGkkkzbWgmMyQZoYz9Db/DD3CrnyC4EJf6GaaPhbYeCDmccy/33uOGjEplmu9GYm5+YXEpuZxaWV1b30hvbtVkEAlMqjhggWi4SBJGOakqqhhphIIg32Wk7vYuhn79nghJA36n+iFxfNTh1KMYKS210ubNGbR9yluxLbqBTbntI9V1vfh2MGjCcrbxcJlzDvSf27/Knp+Wcq10xsybI8BZYk1IBkxQaaW/7HaAI59whRmSsmmZoXJiJBTFjAxSdiRJiHAPdUhTU458Ip14dNkA7mmlDb1A6McVHKm/O2LkS9n3XV053FtOe0PxXy/s9iXFcmq88k6cmPIwUoTj8XQvYlAFcJgdbFNBsGJ9TRAWVB8AcRcJhJVOOKWTsaZzmCW1w7xVyB9dFzLF0iSjJNgBuyALLHAMiqAMKqAKMHgEz+AFvBpPxpvxYXyOSxPGpGcb/IHx/QM/BKdM</latexit>
Future Work Extend to finite-size numerical framework for CVQKD.
Encapsulate different models of imperfect detectors, e.g. trusted noise.
The Institute for Quantum Computing is supported in part by Innovation, Science and Economic Development Canada. T.U. acknowledges the support of NSERC through the Alexander Graham Bell Canada Graduate Scholarship. This research has been supported by NSERC under the Discovery Grants Program, Grant No. 341495, and under the Collaborative Research and Development Program, Grant No. CRDP J 522308-17. Financial support for this work has been partially provided by Huawei Technologies Canada Co., Ltd.
References[1] A. Winick, N. Lütkenhaus, and P. J. Coles, Quantum 2, 77 (2018).[2] P. J. Coles, Phys. Rev. A 85, 042103 (2012).[3] J. Lin, T. Upadhyaya, and N. Lütkenhaus, Phys. Rev. X 9, 041064 (2019).[4] I. Devetak and A. Winter, Proc. R. Soc. A 461, 207 (2005).[5] A. Winter. (2016) , Communications in Mathematical Physics, 347(1):291–313.
f(⇢) = H(X|E)�(⇢)
<latexit sha1_base64="U2TNg1DWfReeNlKmfkH3uxG3xtQ=">AAACGXicbVDLSsNAFJ34rPUVddnNYBHaTUmkohuhKEKXFewDmlAm00kzdDIJMxMhxC78Dj/ArX6CO3Hryi/wN5y2WWjrgQuHc+7lcI8XMyqVZX0ZK6tr6xubha3i9s7u3r55cNiRUSIwaeOIRaLnIUkY5aStqGKkFwuCQo+Rrje+nvrdeyIkjfidSmPihmjEqU8xUloamCW/4oggql42K72Hm+ogc+KAzqXJwCxbNWsGuEzsnJRBjtbA/HaGEU5CwhVmSMq+bcXKzZBQFDMyKTqJJDHCYzQifU05Col0s9kTE3iilSH0I6GHKzhTf19kKJQyDT29GSIVyEVvKv7rxUEqKZYL8cq/cDPK40QRjufpfsKgiuC0JjikgmDFUk0QFlQ/AHGABMJKl1nUzdiLPSyTzmnNrtfObuvlxlXeUQGUwDGoABucgwZoghZoAwwewTN4Aa/Gk/FmvBsf89UVI785An9gfP4AlCuf7g==</latexit>
ProtocolQuantum Phase
Classical Phase• Error Correction: Reverse Reconciliation• Privacy Amplification
Alice
QPSK
|↵i
<latexit sha1_base64="VhPJ5IZp0C024lS6sEasFXf7viI=">AAACCHicbVBLSgNBEO2Jvxh/UZduGoPgKsxIRJdBNy4jmA9khtDT6Uma9PQ03TXCMOQCHsCtHsGduPUWnsBr2ElmoYkPCh7vVVFVL1SCG3DdL6e0tr6xuVXeruzs7u0fVA+POiZJNWVtmohE90JimOCStYGDYD2lGYlDwbrh5Hbmdx+ZNjyRD5ApFsRkJHnEKQEr+f6EQe4TocZkOqjW3Lo7B14lXkFqqEBrUP32hwlNYyaBCmJM33MVBDnRwKlg04qfGqYInZAR61sqScxMkM9vnuIzqwxxlGhbEvBc/T2Rk9iYLA5tZ0xgbJa9mfivp8aZ4dQsrYfoOsi5VCkwSRfbo1RgSPAsFTzkmlEQmSWEam4fwHRMNKFgs6vYZLzlHFZJ56LuNeqX941a86bIqIxO0Ck6Rx66Qk10h1qojShS6Bm9oFfnyXlz3p2PRWvJKWaO0R84nz/Qb5rs</latexit>
|i↵i
<latexit sha1_base64="BG5C3O//d12oMdr8bqbPR6njsS8=">AAACCXicbVBLSgNBEO2Jvxh/UZduGoPgKsyIosugG5cRzAcyQ+jp1GSa9PS03T1CGHICD+BWj+BO3HoKT+A17CSz0MQHBY/3qqiqF0rOtHHdL6e0srq2vlHerGxt7+zuVfcP2jrNFIUWTXmquiHRwJmAlmGGQ1cqIEnIoROObqZ+5xGUZqm4N2MJQUKGgkWMEmOlwB+ByZlPuIzJpF+tuXV3BrxMvILUUIFmv/rtD1KaJSAM5UTrnudKE+REGUY5TCp+pkESOiJD6FkqSAI6yGdHT/CJVQY4SpUtYfBM/T2Rk0TrcRLazoSYWC96U/FfT8ZjzaheWG+iqyBnQmYGBJ1vjzKOTYqnseABU0ANH1tCqGL2AUxjogg1NryKTcZbzGGZtM/q3nn94u681rguMiqjI3SMTpGHLlED3aImaiGKHtAzekGvzpPz5rw7H/PWklPMHKI/cD5/AKJIm18=</latexit>
|�i↵i
<latexit sha1_base64="PynLs45AedIJnwRF5zBg8APWPP4=">AAACCnicbVDLSsNAFJ3UV62vqks3g0VwY0mkosuiG5cV7AOaWCbTSTN0MgkzN0II/QM/wK1+gjtx60/4Bf6G0zYLbT1w4XDOvdx7j58IrsG2v6zSyura+kZ5s7K1vbO7V90/6Og4VZS1aSxi1fOJZoJL1gYOgvUSxUjkC9b1xzdTv/vIlOaxvIcsYV5ERpIHnBIw0oM7ZpCfcZeIJCSTQbVm1+0Z8DJxClJDBVqD6rc7jGkaMQlUEK37jp2AlxMFnAo2qbipZgmhYzJifUMliZj28tnVE3xilCEOYmVKAp6pvydyEmmdRb7pjAiEetGbiv96SZhpTvXCegiuvJzLJAUm6Xx7kAoMMZ7mgodcMQoiM4RQxc0DmIZEEQomvYpJxlnMYZl0zutOo35x16g1r4uMyugIHaNT5KBL1ES3qIXaiCKFntELerWerDfr3fqYt5asYuYQ/YH1+QMS0JuW</latexit>
|�↵i
<latexit sha1_base64="2YQDr8qYBi7hYW4Kl+uI+PmnHaM=">AAACCXicbVDLSsNAFJ3UV62vqks3g0VwY0mkosuiG5cV7AOaUCbTSTN0MokzN0II/QI/wK1+gjtx61f4Bf6G0zYLbT1w4XDOvdx7j58IrsG2v6zSyura+kZ5s7K1vbO7V90/6Og4VZS1aSxi1fOJZoJL1gYOgvUSxUjkC9b1xzdTv/vIlOaxvIcsYV5ERpIHnBIwkueOGeRnLhFJSCaDas2u2zPgZeIUpIYKtAbVb3cY0zRiEqggWvcdOwEvJwo4FWxScVPNEkLHZMT6hkoSMe3ls6Mn+MQoQxzEypQEPFN/T+Qk0jqLfNMZEQj1ojcV//WSMNOc6oX1EFx5OZdJCkzS+fYgFRhiPI0FD7liFERmCKGKmwcwDYkiFEx4FZOMs5jDMumc151G/eKuUWteFxmV0RE6RqfIQZeoiW5RC7URRQ/oGb2gV+vJerPerY95a8kqZg7RH1ifP0DImyM=</latexit>
q
p
Bob
Parameter Estimation
q
p
q
p
Key Map
Uncharacterized Quantum Channel
Authenticated Classical Channel
n rounds
Heterodyne Measurement
Results for Typical Simulation
Lossy and noisy channel, with ξ=0.01
50 100 150 200Distance (km)
10-6
10-4
10-2
100
Key
Rat
e
N=10N=20GaussianCutoff
Infinite and Finite Optimizations
Require: ⇧NS1⇧N ✓ SN
<latexit sha1_base64="A+OqFwr2XgXCF2OcR8FMqbXiq6g=">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</latexit>
W � 1� Tr(⇢⇧N ) 8⇢ 2 S1
<latexit sha1_base64="AkA9Z0kjid9foEyxuuHSfkUKZCQ=">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</latexit>
min f(⇢)subject to:⇢ 2 Pos(H1
AB)Tr(⇢) = 1⇢ 2 S1
<latexit sha1_base64="g//kb/EjTzKWPG6f/3JxbWNVMe4=">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</latexit>
f(⇢1) =
<latexit sha1_base64="0Xx+L2SgK4pXGRhLXgoQwu9CFz8=">AAACDXicbVDLSsNAFJ34rPXRqEs3g0Wom5JIRTdC0Y3LCvYBTSyT6aQZOpkJMxMhhH6DH+BWP8GduPUb/AJ/w2mbhbYeuHA4517uvSdIGFXacb6sldW19Y3N0lZ5e2d3r2LvH3SUSCUmbSyYkL0AKcIoJ21NNSO9RBIUB4x0g/HN1O8+Eqmo4Pc6S4gfoxGnIcVIG2lgV8KaJyPx4FEe6uz0amBXnbozA1wmbkGqoEBrYH97Q4HTmHCNGVKq7zqJ9nMkNcWMTMpeqkiC8BiNSN9QjmKi/Hx2+ASeGGUIQyFNcQ1n6u+JHMVKZXFgOmOkI7XoTcV/vSTKFMVqYb0OL/2c8iTVhOP59jBlUAs4jQYOqSRYs8wQhCU1D0AcIYmwNgGWTTLuYg7LpHNWdxv187tGtXldZFQCR+AY1IALLkAT3IIWaAMMUvAMXsCr9WS9We/Wx7x1xSpmDsEfWJ8/l0mbvg==</latexit>
min f(⇢)subject to:⇢ 2 Pos(HN
AB)1�W Tr(⇢) 1⇢ 2 SN
<latexit sha1_base64="sLW1tuEze65OkJghVBxXbQI17XA=">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</latexit>
f(⇢N ) =
<latexit sha1_base64="PPR7CDoc2uf+Q/sZonrFN3ifeyQ=">AAACBnicbVDLSsNAFL2pr1pfVZdugkWom5JIRTdC0Y0rqWAf2MYymU7aoZOZMDMRQujeD3Crn+BO3PobfoG/4bTNQlsPXDiccy/33uNHjCrtOF9Wbml5ZXUtv17Y2Nza3inu7jWViCUmDSyYkG0fKcIoJw1NNSPtSBIU+oy0/NHVxG89Eqmo4Hc6iYgXogGnAcVIG+k+KHflUDzcHF/0iiWn4kxhLxI3IyXIUO8Vv7t9geOQcI0ZUqrjOpH2UiQ1xYyMC91YkQjhERqQjqEchUR56fTisX1klL4dCGmKa3uq/p5IUahUEvqmM0R6qOa9ifivFw0TRbGaW6+Dcy+lPIo14Xi2PYiZrYU9ycTuU0mwZokhCEtqHrDxEEmEtUmuYJJx53NYJM2TilutnN5WS7XLLKM8HMAhlMGFM6jBNdShARg4PMMLvFpP1pv1bn3MWnNWNrMPf2B9/gDAvJkj</latexit>
f(⇢N )� ✏N (W ) f(⇢1)
<latexit sha1_base64="J847NJYFdj0L6JpWViPBNOHylAE=">AAACKXicbVDLSsNAFJ34tr6iLt0MFqFFLIlUdCm6cSUK9gFNLJPpTTt0MokzEyEEP8Lv8APc6ie4U7cu/A2nNQutHrhwOOdeDvcECWdKO86bNTU9Mzs3v7BYWlpeWV2z1zeaKk4lhQaNeSzbAVHAmYCGZppDO5FAooBDKxiejvzWLUjFYnGlswT8iPQFCxkl2khdezeseHIQX59X9zxIFONGPK+0qtjjcIML02Mi1Fm1a5edmjMG/kvcgpRRgYuu/en1YppGIDTlRKmO6yTaz4nUjHK4K3mpgoTQIelDx1BBIlB+Pn7qDu8YpYfDWJoRGo/Vnxc5iZTKosBsRkQP1KQ3Ev/1kkGmGFUT8To88nMmklSDoN/pYcqxjvGoNtxjEqjmmSGESmYewHRAJKHalFsyzbiTPfwlzf2aW68dXNbLxydFRwtoC22jCnLRITpGZ+gCNRBF9+gRPaFn68F6sV6t9+/VKau42US/YH18Aeuaplc=</latexit>
!!
!N!!!N!N
HN
H!
SN
|f (!!)" f (!N!!!N)| # "N(W )
f (!N!!!N) $ f (!N)
W
R = I(A : B)� �(X : E)
<latexit sha1_base64="A7W7f3SElDiIvvR+8ruTTKErzys=">AAACEXicbVDLSsNAFJ34rPUV7dJNsAjtwpJIRSkItSLorop9QBvKZDpphk4mYWYihNCv8APc6ie4E7d+gV/gbzhps9DWAxcO59zLvfc4ISVCmuaXtrS8srq2ntvIb25t7+zqe/ttEUQc4RYKaMC7DhSYEoZbkkiKuyHH0Hco7jjjq9TvPGIuSMAeZBxi24cjRlyCoFTSQC/cX9yWLmuN8nEfeaTUrV2X8wO9aFbMKYxFYmWkCDI0B/p3fxigyMdMIgqF6FlmKO0EckkQxZN8PxI4hGgMR7inKIM+FnYyPX5iHCllaLgBV8WkMVV/TyTQFyL2HdXpQ+mJeS8V//VCLxYEibn10j23E8LCSGKGZtvdiBoyMNJ4jCHhGEkaKwIRJ+oBA3mQQyRViGky1nwOi6R9UrGqldO7arHeyDLKgQNwCErAAmegDm5AE7QAAjF4Bi/gVXvS3rR37WPWuqRlMwXwB9rnDyXWmz4=</latexit>