Quantum Technologies, Quo Vadis ? Nicolas Gisin GAP-Quantique, University of Geneva From the HLSC Report to the SRA Soft Geneva Geneva University underbelly spot Quantique GAP GAP 1 NG et al., IEEE J. Lightwave Polarization Mode Dispersion Technology, 9, 821-827, 1991. * P.M coupling 1 1’ 2’ 2 2’ 2 * 4 Geneva Geneva University 4’ 3’ Quantique GAP GAP A single mode fiber behaves like a many mode fiber. Many path interferences High coherence Laser Swisscom SOS: Sometimes we observe anomalously large PMD, larger than the «sum» of the components! How can that be? We checked everything Polarimeter very carefully. Geneva Geneva University Quantique Interference between paths in the test fiber GAP GAP Sensitive to environment artifacts 3 Anomalous PMD Geneva Geneva University Quantique GAP GAP B. Huttner, Ch. Geiser and N. Gisin, Optics Commun. 142, 119, 1997; IEEE J. Quant. Elect., 2000 4 From optical technology to subtle quantum measurement effect Slow and fast light in an optical fiber PRL 93, 203902, 2004 Geneva Geneva University Experimental results • Group velocity increases Quantique GAP GAP • Signal velocity remains constant 5 Weak Quantum Measurements Central theme of quantum technologies Consider a simple textbook detector model: A classical pointer on a scale is shifted by the value corresponding to the number | S of photons in the state. B σ If the initial position of the pointer is δ-peaked, it corresponds to a projective photon number measurement Geneva Geneva University But when the pointer has a non-zero spread σ the detector only gives a Partial information on the number of photons in the system (weak measurement) Quantique GAP GAP + post-selection weak values 6 Quantum Nonlocality and Entanglement Aspect et al. 1997 1981 Geneva Geneva University Quantique GAP GAP Entanglement is nonlocal randomness: 7 one random event that manifests itself at several locations. GAP Quantique Geneva University A loophole Ronald Hanson’s group Ronald Hanson’s - free Bell test in in testBell free Delft Applied Physics: From Bell tests to Quantum cryptography 100% correlation perfect key No cloning secret key Alice Bob * Geneva Geneva University W. Tittel et al., PRL 81, 3563-3566, 1998 Quantique GAP GAP 9 Quantum cryptography below lake Geneva Alice Bob A t t . PBS * F.M. Geneva Geneva University Nature 378, 449, 1995. Applied Phys. Lett. 70, 793-795, 1997. Quantique Electron. Letters 33, 586-588, 1997; 34, 2116-2117, 1998. GAP GAP J. Modern optics 48, 2009-2021, 2001. 10 New simple and efficient QKD protocol Geneva Geneva University Superconducting 2.5 GHz Ultralow-loss detectors repetition rate fibers developed in transmitter Geneva Quantique GAP GAP Secret key rate vs distance x X Toshiba 2018 and 2017 GVA 2019 2Mbit/s 60 km best CV result: Huang et. al. 2016 x Geneva Geneva University Quantique GAP GAP Device-Independent Q info Processing Alice Bob x=0 or 1 y=0 or 1 0 1 0 1 If p(a,b|x,y) violates some Bell inequality, then p(a,b|x,y) contains secrecy a b irrespective of any detail of the Geneva Geneva University implementation ! untrusted untrusted After publicly announcing a fair sample of their data, Quantique Alice and Bob’s information is entirely contained in the conditional probability GAP GAP p(a,b|x,y) 13 GAP Quantique Geneva University Q computing Q computing & supremacy 14 GAP Quantique Geneva University Continuous weak measurement Continuous 15 Quantum Repeaters Bridging long distances Geneva Geneva University Multimode QMs to solve the Rate Problem Single-mode storage: rate limited by L0/c N-mode storage: rate limited by NL /c Quantique 0 GAP GAP Multimode QMs required for practical repeaters Quantum memory Goal: controlled and reversible mapping of a photonic quantum state onto a long lived atomic ensemble. crystal doped with billions of ions photon out at desired photon in time in same Q state The quantum state of the photon Geneva Geneva University is now coded in a huge entangled states of billions of « atoms » Quantique GAP GAP 17 Multimode Storage using Ensemble-based QMs Ensembles can store light using different degrees of freedom Time multiplexing in rare-earth-ion doped crystals with the Atomic Frequency Comb (AFC) memory Geneva Geneva University Quantique GAP GAP Multimode spin-photon correlations – 1 ms storage Second-order cross-correlation function Geneva Geneva University Quantique The Stokes/anti-Stokes pairs have a coherence time of 410 ns. GAP GAP About 12 temporal modes per 10 microseconds detection gates. C. Laplane, P. Jobez, J. Etesse, N. Gisin, and M. Afzelius, PRL 118, 210501 (2017) Towards long duration storage (>1 seconds) 151 3+ in Eu :Y2SiO5 Geneva Geneva University Quantique GAP GAP Novel material based on the hybridization of electronic-nuclear states Geneva Geneva University Quantique GAP GAP A. Tiranov, A. Ortu, S. Welinski, A. Ferrier, P. Goldner, N. Gisin, M. Afzelius Nature Materials 17, 671 (2018) GAP Quantique Geneva University 22 Quantum Networks with independent sources and joined Q measurements Certify quantumness of networks Geneva Geneva University Quantique GAP GAP 23 NG, Entropy, «25 years of Q teleportation», 21,325 (2019) The Triangle with binary outcomes a =±1 A 6 qubit toy universe, without How to formalize and input. How to prove exploit the NSI principle? Alice quantumness? How to One has only access to prove that the outcomes P(a,b,c). contain some randomness? Bob Charlie b=±1 c =±1 Geneva Geneva University There are no inputs. However, Alice can decide not to perform any measurement, or to change the local topology, that should not affect the B-C correlation: no-signaling. Quantique GAP GAP 24 The Triangle with binary outcomes a =±1 d=±1 Alice Dave Bob Charlie b=±1 c =±1 Geneva Geneva University There are no inputs. However, Alice can decide not to perform any measurement, or to change the local topology, that should not affect the B-C correlation: no-signaling. Quantique Alice and Charlie are independent. Similarly, GAP GAP Dave and Bob are independent. NSI 25 Machine Learning Neural networks “cat” a p(a|β γ) p(b|γ α) p(c|α β) Geneva Geneva University γ * β Quantique GAP GAP α b c γ α β 26 Quantum Networks arXiv:1901.08287 (Finner ineq.), PRL 123, 070403 (2019) arXiv:1906.06495 (Salman Triangle), PRL 123. 140401 (2019) arXiv:1905.04902 (NSI principle) arXiv:1907.10552 (Machine learning) Geneva Geneva University Quantique GAP GAP 27 From (pretty trivial) Physics to (serious) Technology Geneva Geneva University Quantique • A conceptually simple entropy source • Only quantum physics offers fundamental randomness GAP GAP • Easy to pindown the origine of the randomness • A practical random number generator GAP Quantique Geneva University 29 GAP Quantique Geneva University Launchof QRNG - chip QRNG-chip . Launch of Quantis QRNG chip Next Generation . Smallest QRNG . Standards compliant randomness (meet NIST 800-90A/B/C requirements) . Quantis 6M QRNG Chip certified for automotive (AEC-Q100) – 6Mbps raw data . Quantis 20M QRNG chip for higher throughput - 20Mbps raw data . New Quantis Appliance designed for high availability data centers . Standards compliant randomness (NIST 800-90A/B/C compliant) in FIPS 140-2 compliant hardware . High availaiblity with redundant power & fans . Quantis QA2 with 16Mbps and 60Mbps Geneva Geneva University . Provides randomness as a service for multiple remote applications . Next Generation Quantis PCIe card Quantique . Smaller form factor with higher throughput (10Mbps and 60Mbps) GAP GAP . Standards compliant randomness (NIST 800-90A/B/C compliant) 3 ment strat egies, occurring with probabilities p(x) and a pseudo randomness generat or). The second assump- p(λ) respectively, is then given by tions concerns the overlap of the two prepared stat es. X X We assume that , in each round of the prot ocol, the two λ λ pg = p(x) p(λ) max{ Tr[⇢x ⇧ ø], 1− Tr[⇢x ⇧ ø ]} , (1) prepared stat es cannot be perfectly distinguished (using x λ any possible quantum measurement procedure). If the two stat es are pure, it is possible to discriminat e them λ where ⇢x = | x i h x |, and ⇧ b are the elements of a without any error, at the price of having a minimal rat e three-outcome positive-operat or-value measure (POVM) of inconclusive rounds, given by the overlap between the describing the measurement. To certify randomness, we two stat es. Note that if the stat es are mixed, with over- need to upper bound pg over all possible measurement lapping support, then they cannot be distinguished un- strat egies which are consistent with the observed exper- ambiguously anymore. We assume that the two prepared imental dat a. Because the trace is invariant under uni- stat es, ⇢0 and ⇢1 fulfill F (⇢0, ⇢1) > δ,where F is the fi- tary transformat ions, only the overlap of the input stat es delity. This condition must hold with respect to any ob- mat ter, and not the stat es themselves. As we explain in server, in particular from the point of view of the measur- App. A, upper bounds on pg can be established by means ing device. No additional informat ion is available which of semidefinite programming (SDP). Specifically, allows picking out specific terms in any decomposition of X the stat es. This ensures that ⇢0 and ⇢1 have a minimal ⇤ indistinguishability from the point of view of the measur- pg 6 pg = ⌫bx p(b|x) (2) b,x ing device. Since, without additional informat ion, going from pure to mixed stat es with the same fidelity cannot for any numbers ⌫bx which fulfil that there exists four help in distinguishing the stat es, taking ⇢0 and ⇢1 pure is λ 0 ,λ 1 2 ⇥2 hermitian mat rices H ,with λ0, λ1 =0, 1such the most conservat ive choice when bounding theguessing that probability, and hence our bound above is general under this assumption.