Email: hklo@comm.utoronto.ca
Current Research
- Quantum information science including quantum cryptography and quantum communication.
Basic setup of a MDI-QKD protocol. Alice and Bob prepare phase randomized weak coherent pulses (WCPs) in a different BB84 polarization state which is selected, independently and at random for each signal, by means of a polarization modulator (Pol-M). Decoy states are generated using an intensity modulator (Decoy-IM). Inside the measurement device, signals from Alice and Bob interfere at a 50:50 beam splitter (BS) that has on each end a polarizing beam splitter (PBS) projecting the input photons into either horizontal (H)or vertical (V) polarization states. Four single-photon detectors are employed to detect the photons and the detection results are publicly announced. A successful Bell state measurement corresponds to the observation of precisely two detectors (associated to orthogonal polarizations) being triggered. [Figure taken from H.-K. Lo, M. Curty and B. Qi, Measurement-device-independent quantum key distribution, Physical Review Letters 108, 130503 (2012).]
Left graphic: clique. Right graphic: biclique. In the clique, each vertex is connected with every other. In the biclique, each vertex from the left set is connected with a vertex on the right, but the sets are internally disconnected. These graphs can underlie repeater graph states. [Figure taken from K. Azuma et al., Quantum Repeaters: From quantm networks to the quantum internet, Rev. Mod. Phys. 95, 045006 (2023).]
Selected Publications
- K. Azuma, S. E. Economou, D. Elkouss, P. Hilaire, L. Jiang, H.-K. Lo , and I. Tzitrin, Quantum repeaters: From quantum networks to the quantum internet, Rev. Mod. Phys. 95, 045006 (2023).
- W. Wang, R. Wang, C. Hu, V. Zapatero, L. Qian, B. Qi, M. Curty, and H.-K. Lo, Fully Passive Quantum Key Distribution, Phys. Rev. Lett. 130, 220801 (2023).
- X. Zhong, W. Wang, R. Mandil, H.-K. Lo and L. Qian, Simple Multiuser Twin-Field Quantum Key Distribution Network, Phys. Rev. Applied 17, 014025 (2022) [Selected as Editors’ Suggestion].
- F. Xu, X. Ma, Q. Zhang, H.-K. Lo, and J.-W. Pan, Secure Quantum Key Distribution with Realistic Devices, Rev. Mod. Phys. 92, 025002 (2020) (ESI hot paper, cited 1314 times).
- X. Zhong, J. Hu, M. Curty, L. Qian, and H.-K. Lo, Proof-of-Principle Experimental Demonstration of Twin-Field Type Quantum Key Distribution, Phys. Rev. Lett. 123, 100506 (2019), [Selected as PRL Ed-itors’ Suggestion. See Synopsis: Long Haul Quantum Communication https://physics.aps.org/synopsis-for/10.1103/PhysRevLett.123.100505].
- M. Curty, K. Azuma, and H.-K. Lo, Simple Security Proof of Twin-Field Type Quantum Key Distribution Protocol, npj Quantum Inf. 5, 64 (2019).
- W. Wang, F. Xu, and H.-K. Lo, Asymmetric Protocols for Scalable High-Rate Measurement-Device-Independent uantum key distribution networks, Phys. Rev. X 9, 041012 (2019).
- K. Azuma, K. Tamaki, H.-K. Lo, All-photonic quantum repeaters, Nat. Commun. 6(1) 1-7 (2015).
- H.-K. Lo, M. Curty and K. Tamaki, Secure Quantum Key Distribution (Invited Review Paper), Nat. Photonics 8, 595-604 (2014) (cited 1362 times).
- Z. Tang, Z. Liao, F. Xu, B. Qi , L. Qian, H.-K. Lo, Experimental demonstration of polarization encoding measurement-device-independent quantum key distribution, Phys. Rev. Lett. 112, 190503 (2014).
Affiliations & Links
- IEEE Quantum Electronics Award (2023)
- QCMC International Quantum Award (2024)
- Co-founder and CSO, Quantum Bridge Technologies (QBT), Inc