Randomness extraction from Bell violation with continuous parametric - - PowerPoint PPT Presentation
Randomness extraction from Bell violation with continuous parametric down conversion Lijiong Shen Jianwei Lee Alessandro Cer` e Le Phuc Thinh Valerio Scarani Christian Kurtsiefer Centre for Quantum Technologies Jean-Daniel Bancal
Randomness extraction from Bell violation with continuous parametric down conversion
Lijiong Shen Jianwei Lee Alessandro Cer` e Le Phuc Thinh Valerio Scarani Christian Kurtsiefer
Centre for Quantum Technologies
Jean-Daniel Bancal University of Basel, CH Antia Lamas-Linares Texas Advanced Computing Center, USA Thomas Gerrits Adriana E. Lita Sae Woo Nam NIST, USA
lijiong.shen@u.nus.edu
Secure private communication requires Randomness
Classical systems cannot guarantee unpredictability
https://en.wikipedia.org/wiki/RANDU Secure private communication requires Randomness
Classical systems cannot guarantee unpredictability
https://en.wikipedia.org/wiki/RANDU Non-classical correlations certify genuine randomness
αx βy
Alice Bob Correlation for measurement settings αx, βy Ex,y = P(a = b|x, y) − P(a = b|x, y) Bell parameter from 4 settings S = E00 + E01 + E10 − E11
1 2 2 2 bit/round
|S|
1 2 2 √2
we are here
Our point to the state of the art
10−4 10−2 100 102 2010 2013 2017 2018 bits/s year 1.5e-5 .4 114 1.8
Bell test with CW source and two detectors
αx βy
Alice Bob
time Alice Bob
Bell test with CW source and two detectors
αx βy
Alice Bob
time Alice Bob + + + + +
Correlation depends on bin width τ
time Alice Bob
Correlation depends on bin width τ
E = N++ + N−− − N−+ − N+− N
= 2
3
time Alice Bob + + + + + + + + + = 30 s
Correlation depends on bin width τ
E = N++ + N−− − N−+ − N+− N
= −1
9
time Alice Bob + + + + + + + + + + + = 20 s
Experimental setup
TES timestamp SMF-28e
φ
PBS HWP@45 HWP@45 HWP SMF@810nm P P K T P PBS PBS LD@405nm
θ
SMF PM @405nm efficiency > 98%
|ψ = cos θ |HV − eiφ sin θ |VH
jitter ≈ 170ns
P . H. Eberhard, Phys. Rev.A(1993) Pair generation rate ≈ 24 000/s for 5 mW of UV pump
19.8 24 kcps Alice Bob
2/ 3
41.5 45.7 dark count/s 82.4% 82.2%
Optimal setting for loophole free Bell test - State
|ψ ≈ 0.9 |HV − 0.43 |VH
VV VH HV HH HH HV VH VV
Optimal setting for loophole free Bell test - State
|ψ ≈ 0.9 |HV − 0.43 |VH
VV VH HV HH HH HV VH VV
Optimal setting for loophole free Bell test - Projections
α0 = 7.2◦ α1 = 28.7◦ β0 = 82.7◦ β1 = 61.5◦
We observe a violation of S = 2.01602(32)
16.02 experiment simulation 13.15
≈ 0.32 pairs/round (S − 2) × 10−3
bin width (µs)
Rate of randomness
τ
bit/round
τ
round/s
×
Rate of randomness
1.32 1.93 0.9 4.4 27 s i m u l a t i
e x p e r i m e n t kbits/s bin width (µs)
Finite statistics - Block extraction
m = n · ηopt(εc, εs) + 4 log ǫEX n
− 10
We choose
εc = εs = 10−10
Trevisan extractor based on polynomial hashing with block weak design In 26 min we generated 617 920 random bits (396 bits/s)
Processing time for 26mins data
26 mins data
↓
9 hours processing
Processing time for 10 hours data
10 hours data
↓
28 years processing Toeplitz extractor
↓
943 bits/s in few hours
Our point to the state of the art
10−4 10−2 100 102 2010 2013 2017 2018 bits/s year 1.5e-5 .4 114 1.8 396 943
Conclusion
αx βy
a b
time Alice Bob + + + + +arXiv:1805.02828 2 2.01602 1.32 kbit/s bin width
lijiong.shen@u.nus.edu SUZHOU
lijiong.shen@u.nus.edu Observed violation changes with τ
1.12 2 1000 2000
≈ 24 pairs/round
violation S bin width (µs) simulation experiment 1.12 2 1000 2000
Rate of randomness with finite block size
0.16 .83 1.14 1.32 1.93 4.4 5.6 7.3 12.1 s i m u l a t i
n → inf n = 108 n = 109 n = 1010 kbits/s bin width (µs)