7/31/20 Novel techniques for ground to space quantum channels IQC @ 2019: 31 faculty 157 Grad students 57 Postdoc 1800+ publications $600M+ funding Thomas Jennewein 13 spin-offs Institute for Quantum Computing & Department of Physics and Astronomy, University of Waterloo Thomas.Jennewein@uwaterloo.ca 2020.07 1 2 Quantum Internet Quantum Key Distribution Quantum computing in the cloud: ◥ REVIEW SUMMARY Fixes the loophole of key distribution, where classical keys could be copied or compromised during transport. QUANTUM INFORMATION Only transmit single quanta of light per bit. Quantum internet: A vision for the road ahead Stephanie Wehner * , David Elkouss, Ronald Hanson Science 362, 303 (2018) Alice Bob Eve ? L. O. Mailloux et. al. Journal of Cyber Security and Information Systems, 4, 2 – Basic Complexity 10 11 1
7/31/20 Historical note on QKD V OLUME 84, N UMBER 20 P H Y S I C A L R E V I E W L E T T E R S 15 M AY 2000 Quantum Cryptography with Entangled Photons Thomas Jennewein, 1 Christoph Simon, 1 Gregor Weihs, 1 Harald Weinfurter, 2 and Anton Zeilinger 1 1 Institut für Experimentalphysik, Universität Wien, Boltzmanngasse 5, A-1090 Wien, Austria 2 Sektion Physik, Universität München, Schellingstrasse 4 � III, D-80799 München, Germany ( Received 24 September 1999 ) By realizing a quantum cryptography system based on polarization entangled photon pairs we establish highly secure keys, because a single photon source is approximated and the inherent randomness of quantum measurements is exploited. We implement a novel key distribution scheme using Wigner’s inequality to test the security of the quantum channel, and, alternatively, realize a variant of the BB84 protocol. Our system has two completely independent users separated by 360 m, and generates raw keys at rates of 400–800 bits � s with bit error rates around 3%. PACS numbers: 03.67.Dd, 42.79.Sz, 89.80.+h The primary task of cryptography is to enable two par- In any real cryptography system, the raw key generated ties (commonly called Alice and Bob) to mask confidential by Alice and Bob contains errors, which have to be cor- messages, such that the transmitted data are illegible to any rected by classical error correction [7] over a public chan- unauthorized third party (called Eve). Usually this is done nel. Furthermore, it has been shown that whenever Alice using shared secret keys. However, in principle it is always and Bob share a sufficiently secure key, they can enhance possible to intercept classical key distribution unnoticedly. its security by privacy amplification techniques [8], which The recent development of quantum key distribution [1] allow them to distill a key of a desired security level. FIG. 3 (color). The bit large keys generated by the can cover this major loophole of classical cryptography. It A range of experiments have demonstrated the feasi- allows Alice and Bob to establish two completely secure bility of quantum key distribution, including realizations keys by transmitting single quanta (qubits) along a quan- using the polarization of photons [9] or the phase of pho- tum channel. The underlying principle of quantum key dis- tons in long interferometers [10]. These experiments have tribution is that nature prohibits gaining information on the a common problem: the sources of the photons are attenu- 12 13 Why Satellites for Long Distance Q-Com? Quantum Communication in Space Dedicated quantum hardware in Space: • Ground-based IdQuantique Commercial QKD System • China (J.W . Pan) • Practical systems typically 100 km • Entanglement Distribution over 1200 km ! (Science, 2017) • Demonstrations up to to 400 km • QKD, Teleportation (Nature 549, 43–47 and 70-73 (2017) • Optic fibre loss 0.15 dB/km at best • QKD between Bejing and Graz (PRL), QKD using Bell-pairs • Free-space limited due to line-of-sight (CLEO 2019, Nature2020) • Commercial Devices available: • Note: Optical amplifiers not possible! • Japan (NICT) • 50 kg satellite: Nature Photonics 11, 502–508 (2017) • Singapore (A. Ling) • Longer distances: • Correlated Photon Source onboard CubeSat • Trusted Repeaters (Phys. Rev. Applied 5, 054022, 2016) (> 2000km network China) • Long lifetime Quantum Memories • SpooQey-1: July 2019: Entanglement in space • Quantum Repeaters Beijing and Vienna have a quantum conversation • Satellites 2W(L) September 2017, www.physicsworld.com Takesue et al, Nature Photonics 1, • Several more missions in preparation 2W 0 http://english.cas.cn/newsroom/news/201709/t20170928_1 343 - 348 (2007) 83577.shtml Ma, Fung, Lo, Phys. Rev. A 76, 012307 (2007) 14 19 2
7/31/20 Canadian Quantum Satellite And was noticed by the world! http://www.asc- csa.gc.ca/eng/sciences/qeyssat.asp In the section Pioneers . Announced April, 2018. Minister Bains, April 2017 20 21 Modeling the performance of satellite QEYSSat will be a Technology Demonstration Platform to ground quantum link • Optimized Quantum Receiver • Analysis of wavelengths with windows of • Multiple partners across Canada ‘good’ atmospheric transmission • Transmitter telescopes are ‘compact’ • Link modelled using turbulence; • Networking with fiber optics diffraction to account for beam H Receiver • Test link with various quantum sources obstruction; background signals http://www.spaceq.ca/honeywell-aerospace-wins-30-million-contract-to-build-qeyssat-satellite/ Input from • Study of quantum link and Fiber optics PBS V Bob’s entanglement science telescope Trusted Relay PBS North America – the cutout is centred around Ottawa • Multiple ground stations in Canada, D window: 0.5 ns. and around the globe BS Pinhole Secure key length obtained for the upper quartile satellite pass (kbit) Coupling Wavelength Downlink, WCP Uplink, WCP Downlink, entangled Uplink, entangled lens A • Research on ground station Rotated 45 ˚ (nm) source source photon source photon source 405 68.5 3.5 6.2 0 Location B capabilities such as AO or different 532 264.5 33.1 119.3 12.1 Location A e.g. Waterloo 670 465.6 87.7 324.7 67.4 quantum emitters, etc. e.g. Calgary 785 458.3 111.3 272.9 75.7 Bob 830 317.3 82.1 136.1 39.7 1060 175.4 67.6 21.8 8.1 1550 123.9 94.8 12.8 14.4 Alice M. Toyoshima, op.Ex. 2011 Related analysis: J.P. Bourgoin, et al, NJP, 15:023006, 2013 J. Rarity et al, NJP, 2002 P. Villoresi group, NJP, 2009 R. Ursin group, NJP, 2013 23 29 3
7/31/20 QEYSSat Payload Prototype Ground to Aircraft Demonstration Full quantum receiver optics • Fully functional form-representative quantum-payload • Components have ‘path to flight’ • Projected mass: ~ 23 kg, Power <30W, envelope ~ 60cm^3 • Tests: Radiation, TVAC, aircraft link Payload detectors and electronics C. Pugh et al., Quantum Science and Technology, 2017; 2 (2): 024009 Press release: https://uwaterloo.ca/institute-for-quantum-computing/news/iqc- advances-quantum-satellite-mission 34 36 Airborne QKD tracking system Novel Protocols for Free-Space • Airborne Trials 2016- Sep. 20 / 21 Quantum Communications • Night #1: 7 passes, of which 2 acquired signal. Night #2: 8 passes, of which 5 acquired signal. Lessons learnt from previous tests • 3 km line pass: secure key (finite size included) of 46805 3km pass: bit, 35 seconds. - Reference Frame Independent QKD • 10 km arc pass: secure key (finite size - Alternative Encoding of Photonic Qubits included) 41899 bit, 250 seconds. - HOM Interference with Structured Pulses C. Pugh et al, Quantum Science and Technology, 2, 2, 024009 (2017) 37 38 4
7/31/20 Our satellite receiver has limited resource I. Reference-Frame Alignment of 4 states • Challenge for QKD implementations R. Tannous,. MsC thesis, 2018. • New variant of the protocol: 6 – 4 state protocol • How to align the reference frames Arxiv 1905.09197 (e.g. polarization states at Alice have A. Laing et. al, Phys. Rev. A, 82(1):012304, Jul 2010. to match Bob’s)? Channel Verification: • Particular problem in our case is the 4 States (H, V, D, A) q h X A X B i 2 + h Y A X B i 2 , C = motion of the telescope | Ψ i = 1 • Realtime Compensation: ( | 0 i A | 1 i B + e � i φ | 1 i A | 0 i B ) p h σ Z ⌦ σ Z i = (1 � 2 Q ) 2 h σ X ⌦ σ X i = (1 � 2 Q ) · cos θ Location B e.g. Waterloo h σ Y ⌦ σ X i = � (1 � 2 Q ) · sin θ Bob 6 stats – H, V, D, A, L, R h σ V ⌦ σ X i = (1 � 2 Q ) σ V = (cos θ ) σ X � (sin θ ) σ Y arxiv.org 1810.04112 C will be constant even under varying phase theta, and if C drops <1, would reveal Eve! Airborne Transmitter, Smith Falls, 2016 Tomography Compensation 39 41 R. Tannous, APPLIED PHYSICS LETTERS, 115(21), 2019. Experimental Setup Results Slow axis = V The phase is varied by tuning a birefringent element. • Transmission over polarization maintaining fiber Fast axis = H Coincidence Counts Tomography to determine purity of state Birefringent walkoff QBER HV = 1 �h Z ⌦ Z i = N bad N total , 2 | Ψ i = 1 QBER* Diag = 1 � C ( | 0 i A | 1 i B + e � i φ | 1 i A | 0 i B ) 2 . p 2 R � Q λ ( 1 � fH 2 ( QBER HV ) � H 2 ( QBER* Diag )) R. Tannous, APPLIED PHYSICS LETTERS, 115(21), 2019. 42 43 5
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