Recent works

We're theorists working with experimentalists
(with ETRI) Secure Quantum Communication with the Preservation of Optimal Measurements IEEE JSAC (2025) (with POSTECH) Entanglement witness measurement of time-bin two-qubit states using fiber based Franson interferometers, Hwang K, Seong J, Park K, Kim J, Pramanik T, Bae J and Shin H, Frontiers in Physics 11 1254044 (2023)(with KIST, Yonsei) Single-copy certification of two-qubit gates without entanglement Yujun Choi, Tanmay Singal, Young-Wook Cho, Sang-Wook Han, Kyunghwan Oh, Sung Moon, Yong-Su Kim, and Joonwoo Bae, Phys. Rev. Applied 18, 044046 (2022) (with POSTECH) Experimental realisation of an approximate transpose operation for qutrit systems using structural physical approximation, H.-T. Lim, Y.-S. Ra, Y.-S. Kim, J. Bae, and Y.-H. Kim,Physical Review A 86, 042334 (2012).(with POSTECH) Experimental Realization of an Approximate Partial Transpose for Photonic Two-Qubit Systems, H.-T. Lim, Y.-S. Ra, Y.-S. Kim, J. Bae, Y.-H. Kim, Physical Review Letters 107, 160401 (2011).(with POSTECH) Experimental Implementation of the Universal Transpose Operation, H.-T. Lim, Y.-S. Ra, Y.-S. Kim, J. Bae, and Y.-H. Kim, Physical Review A 83, 020301(R) (2011).

We're quantum engineers to develop the present-day quantum technologies: algorithms and hardware interface
[1]Feature Map for Quantum Data in Classification, Hyeokjea Kwon, Hojun Lee and Joonwoo Bae, Oral Presentation@IEEE International Conference on Quantum Communications, Networking, and Computing (QCNC 2024)[2] Detecting Entanglement-Generating Circuits in Cloud-Based Quantum Computing, Jiheon Seong and Joonwoo Bae, spj Intelligent Computing 2 0051 (2023) [3] Measurement crosstalk errors in cloud-based quantum computing services, Seungchan Seo and Joonwoo Bae, IEEE Internet Computing Vol 26 Issue 1 page 26-33 (2022)[4] Quantum amplitude amplification operators (QAAO), Hyeokjea Kwon and Joonwoo Bae, Physical Review A 104 062438 (2021) Editors' Suggestion[5] A hybrid quantum-classical approach to mitigating measurement errors in quantum algorithms, Hyeokjea Kwon and Joonwoo Bae, IEEE Transactions on Computers, Vol 70 (9) 1401 (2021)[6] Information-theoretic meaning of quantum information flow and its applications to amplitude amplification algorithms, Sudipto Singha Roy and J. Bae, Phys. Rev. A 100, 032303 (2019)

Designing a detector for mitigating measurement readout errors in NISQ computing

Realizing a single QAAO in IBMQ

Verifying crosstalk errors in NISQ

Enhancement of NISQ computing and algorithms by quantum error mitigation. Example: IBMQ Yorktown & IBMQ Essex.

Realizing 3-qubit quantum database search in IonQ

We characterize fundamental limitations: quantum channels and quantum protocols
We're interested in security at a higher level and more efficient network communication (a higher capacity) with quantum systems over classical limitations. [1] Purification of noisy measurements and faithful distillation of entanglement, Jaemin Kim, Jiyoung Yun, and Joonwoo Bae, Journal of Physics A: Mathematical and General 58 03LT01 (2025)[2] Quantum advantages in (n,d)->1 random access codes, Andris Ambainis, Dmitry Kravchenko, Sk Sazim, Joonwoo Bae, and Ashutosh Rai, New Journal of Physics 26 123023 (2024)[3] Contextual advantages and Certification for Maximum Confidence Discrimination
Kieran Flatt, Hanwool Lee, Carles Roch i Carceller, Jonathan Bohr Brask, and Joonwoo Bae, PRX Quantum 3 030307 (2022) [4] Quantum vs. Noncontextual Semi-Device-Independent Randomness CertificationCarles Roch i Carceller, Kieran Flatt, Hanwool Lee, Joonwoo Bae, and Jonathan Bohr Brask, Physical Review Letters 129 050501 (2022)[5] A quantum measurement can be preserved by a channel.
Channel Coding of a Quantum Measurement
S. Kechrimparis, C. M. Kropf, F. Wudarski, and J. Bae*, IEEE Journal on Selected Areas in Communications, Vol 38, No 3, 439 (2020)
see Erratum IEEE JSAC Vol 38 No 5 980 (2020) Link[6] Nonlocal correlations are useful in network information theory.
Non-Local Network Coding in Interference Channels
Jiyoung Yun, Ashutosh Rai, and Joonwoo Bae, Physical Review Letters 125 150502 (2020)

Two-sender and two-receiver interference channel. Two senders encode messages with nonlocal correlations.

Higher confidence on a quantum measurement over a classical model

Local operations and classical communication can preserve an optimal quantum measurement.

Randomness certification in a semi-device-independent scenario

We work on theoretically challenging problems: entanglement theory
[1] MUBs can detect entangled states, depending on which MUBs are chosen.
Detecting entanglement can be more effective with inequivalent mutually unbiased bases
B. Hiesmayr, D. McNulty, S Baek, S. Singha Roy, J. Bae, and D. Chruscinski, New. J. Phys. 23 093018 (2021) [2] Entanglement detection is twice more efficient than we thought before.
Mirrored Entanglement Witnesses
J. Bae, D. Chruscinski, and B. Hiesmayr, npj Quantum Information 6 15 (2020)[3] All entangled states are useful, and moreover, the more entangled, the more useful.
More Entanglement Implies Higher Performance in Channel Discrimination Tasks
J. Bae, D. Chruscinski, and M. Piani, Physical Review Letters 122 140404 (2019)[4] MUBs are useful for entanglement detection when they can't be for tomography.
Linking entanglement detection and state tomography via quantum 2-design
J. Bae, B. Hiesmayr, and D. McNulty, New Journal of Physics, 21 013012 (2019).

An entanglement witness corresponds to two hyperplanes, both can certify entangled states.

Detecting entangled states depends on the choice of MUBs

The more entangled a state is, the more useful it is for channel discrimination tasks