QCLab - Recent changes [en]

Coupling between heat transport and spin transport in metallic ferromagnets

Mahnsoo.Choi — Wed, 23 Sep 2026 02:44:37 GMT

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	[[Category:Condensed Matter Seminars]]		[[Category:Condensed Matter Seminars]]
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			[[Category:Talks]]

Composite fermions: Exotic emergent particles in condensed matter

Mahnsoo.Choi — Wed, 23 Sep 2026 02:44:17 GMT

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	[[Category: Seminars]]		[[Category: Seminars]]
			[[Category:Talks]]

Complete characterization of non-classicality of Gaussian states of light via intensity moments

Mahnsoo.Choi — Wed, 23 Sep 2026 02:43:44 GMT

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	[[Category:Seminars]]		[[Category:Seminars]]
			[[Category:Talks]]

Coherent Quantum Control and Magnetism on atoms – Trapped ion and ESR STM

Mahnsoo.Choi — Wed, 23 Sep 2026 02:43:26 GMT

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	[[Category:Condensed Matter Seminars]]		[[Category:Condensed Matter Seminars]]
	[[Category:Seminars]]		[[Category:Seminars]]
			[[Category:Talks]]

Carrier screening and transport in novel chiral 3D Dirac materials

Mahnsoo.Choi — Wed, 23 Sep 2026 02:43:01 GMT

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 * Speaker: [[Hwang, Euyheon]] (Sungkyungkwan University)
 * Date: Wednesday October 14, 2015 17:00
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 Following the very extensive research activity in graphene over the last ten years, a great deal of interest in condensed matter physics has focused on other 2D and 3D Dirac materials where the elementary low energy noninteracting electronic energy dispersion is linear. We introduce the new 3D Dirac materials and present the density and temperature-dependent carrier conductivity in chiral 3D Dirac materials focusing on resistive scattering from screened Coulomb disorder due to random charged impurities. The scaling properties describing how the conductivity depends on the density and temperature can be used to establish the Dirac nature of 3D systems through transport measurements. We also theoretically calculate and compare the single-particle relaxation time \tau_s, defining the quantum level broadening, and the transport scattering time \tau_t, defining the conductivity, in the presence of screened charged impurity scattering. Finally, we present the dependence of the conductivity on carrier density and temperature for arbitrary chiral band dispersion in arbitrary dimensionality. We establish that the temperature and the density dependence of the conductivity manifests scaling behaviors determining, respectively, the intrinsic semimetallic or the extrinsic metallic property of the gapless system.

Bandgap Engineering of Black Phosphorus

Mahnsoo.Choi — Wed, 23 Sep 2026 02:41:52 GMT

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			[[Category:Talks]]

Atomic sputter epitaxy for metal single crystal thin film and its applications for Nanoscience and Photonics

Mahnsoo.Choi — Wed, 23 Sep 2026 02:41:36 GMT

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	[[Category:Condensed Matter Seminars]]		[[Category:Condensed Matter Seminars]]
			[[Category:Talks]]

Antibunching in an optomechanical oscillator.

Mahnsoo.Choi — Wed, 23 Sep 2026 02:41:10 GMT

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	{{Media/Button\|S-HJ2017d.pdf\|Talk slides}}		{{Media/Button\|S-HJ2017d.pdf\|Talk slides}}



	[[Category:Condensed Matter Seminars]]		[[Category:Condensed Matter Seminars]]
	[[Category:Seminars]]		[[Category:Seminars]]
			[[Category:Talks]]

Anomalous Josephson coupling through Majorana fermions in Time-Reversal Invariant Topological Superconductor

Mahnsoo.Choi — Wed, 23 Sep 2026 02:40:44 GMT

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 * Speaker: [[Chung, Suk Bum]] ([http://ibs-cces.snu.ac.kr/ Institute for Basic Science: Center for Correlated Materials], Seoul National University)
 * Date: Wednesday October 14, 2015 16:00
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 Topological superconductors are gapped superconductors with protected Majorana surface/edge states on the boundary. These Majorana fermions will come in doublets when there is time-reversal symmetry in the topological superconductor. As long as the time-reversal symmetry is preserved, the two Majorana fermions of the doublet does not combine into one complex fermions as the coupling between them are forbidden. In all physical dimensions, this property leads to an anomalous Josephson coupling between topological and trivial superconductors where a nonzero phase difference is preferred. This non-trivial Josephson coupling lead to a parity dependent SQUID current-phase relation and a Zeeman field tuning of the periodicity in the Fraunhofer diffraction pattern. Therefore the detection of such effects will verify whether a superconductor is topological or not.
 * Ref: S B Chung, J Horowitz, X-L Qi, PRB (2013) 88, 214514

Active Nanophotonic and Optoelectronic Devices

Mahnsoo.Choi — Wed, 23 Sep 2026 02:40:06 GMT

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	[[file:No, You-Shin.jpg\|thumb\|x300px\|Prof. No, You-Shin (Konkuk Univ)]]		[[file:No, You-Shin.jpg\|thumb\|x300px\|Prof. No, You-Shin (Konkuk Univ)]]
	~~[[Category:Colloquiums]]~~
	~~[[Category:Seminars]]~~
	* Speaker: Prof. [[No, You-Shin]] (Konkuk Univ)		* Speaker: Prof. [[No, You-Shin]] (Konkuk Univ)
	* Date: October 31, 2017		* Date: October 31, 2017
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	Low-dimensional nanomaterials and nanostructures are emerging building blocks in photonics, nanoelectronics and bioelectronics. In particular, semiconductor nanoscale architectures that can be controllably synthesized or fabricated into different morphologies with tunable electrical and optical properties enable the generation and detection of electrical and optical signals with high sensitivity and spatial resolution. In this talk, I will discuss various active optoelectronic devices using top-down-fabricated and bottom-up-synthesized semiconductors. First, I demonstrate the efficient integration of an electrically driven nanowire light source with metallic tapered nanostrips, exhibiting the generation and propagation of surface plasmons as well as the subwavelength-scale nanofocusing of light. Second, I will present a new nanowire structure in which the material and dopant are modulated specifically at only one end of nanowires, termed tip-modulated nanowires. Characterization of the electrical and optical properties of devices configured from these new structures demonstrates the capability of tip-localized electronic and photonic detection. Lastly, I will discuss the recent advances in shape-controlled deterministic assembly techniques of one-dimensional nanomaterials, enabling the realization of key photonic elements. Our demonstrations of active semiconductor nanodevices provide a substantial opportunity in areas ranging from nanoscale light manipulation, optoelectronic signal detection to biological and chemical sensing.		Low-dimensional nanomaterials and nanostructures are emerging building blocks in photonics, nanoelectronics and bioelectronics. In particular, semiconductor nanoscale architectures that can be controllably synthesized or fabricated into different morphologies with tunable electrical and optical properties enable the generation and detection of electrical and optical signals with high sensitivity and spatial resolution. In this talk, I will discuss various active optoelectronic devices using top-down-fabricated and bottom-up-synthesized semiconductors. First, I demonstrate the efficient integration of an electrically driven nanowire light source with metallic tapered nanostrips, exhibiting the generation and propagation of surface plasmons as well as the subwavelength-scale nanofocusing of light. Second, I will present a new nanowire structure in which the material and dopant are modulated specifically at only one end of nanowires, termed tip-modulated nanowires. Characterization of the electrical and optical properties of devices configured from these new structures demonstrates the capability of tip-localized electronic and photonic detection. Lastly, I will discuss the recent advances in shape-controlled deterministic assembly techniques of one-dimensional nanomaterials, enabling the realization of key photonic elements. Our demonstrations of active semiconductor nanodevices provide a substantial opportunity in areas ranging from nanoscale light manipulation, optoelectronic signal detection to biological and chemical sensing.

			[[Category:Colloquiums]]
			[[Category:Seminars]]
			[[Category:Talks]]

Hyperfine electronic bridge for the excitation of the isomeric state in 229Th nucleus

Mahnsoo.Choi — Tue, 22 Sep 2026 00:46:48 GMT

Created page with "* Speaker: Yingdan Wang (Institute of Theoretical Physics, CAS, China) * Event: Quantum Technology Workshop 2026 * {{Media/Button|QTW2026-Wang.pdf|Slides (PDF)}} The 229Th nuclear isomer serves as a promising platform for quantum metrology based on nuclear optical transitions. In addition to direct optical excitation, the electronic bridge (EB) mechanism provides an efficient alternative pathway for nuclear state manipulation. Previous studies have..."

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* Speaker: [[Wang, Yingdan|Yingdan Wang]] (Institute of Theoretical Physics, CAS, China)
* Event: [[Quantum Technology Workshop 2026]]
* {{Media/Button|QTW2026-Wang.pdf|Slides (PDF)}}

The 229Th nuclear isomer serves as a promising platform for quantum metrology based on nuclear optical transitions. In addition to direct optical excitation, the electronic bridge (EB) mechanism provides an efficient alternative pathway for nuclear state manipulation. Previous studies have demonstrated that hyperfine interactions play a crucial role in two-photon EB processes in 229Th3+ ions, achieving ultra-high fidelity isomeric population transfer via a STIRAP scheme [1]. However, by performing a full calculation that incorporates the complete hyperfine structure, we reveal that the hyperfine splitting in the isomeric 7p1/2 manifold significantly degrades the excitation probability by disrupting the two-photon resonance condition. To overcome this limitation, we propose to combine magic wavelength with quantum interference effects to effectively restoring high-fidelity isomeric excitation.

[[Category: Quantum Technology Workshop 2026]]
[[Category: Talks]]

Wang, Yingdan

Mahnsoo.Choi — Tue, 22 Sep 2026 00:46:45 GMT

Hyperfine electronic bridge for the excitation of the isomeric state in 229Th nucleus

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	[[Category: Speakers]]		[[Category: Speakers]]

	==Hyperfine electronic bridge for the excitation of the isomeric state in 229Th nucleus==		==Contributions==
			* [[Hyperfine electronic bridge for the excitation of the isomeric state in 229Th nucleus]]
	* Speaker: [[Wang, Yingdan\|Yingdan Wang]] (Institute of Theoretical Physics, CAS, China)
	* Event: [[Quantum Technology Workshop 2026]]
	* {{Media/Button\|QTW2026-Wang.pdf\|Slides (PDF)}}

	The 229Th nuclear isomer serves as a promising platform for quantum metrology based on nuclear optical transitions. In addition to direct optical excitation, the electronic bridge (EB) mechanism provides an efficient alternative pathway for nuclear state manipulation. Previous studies have demonstrated that hyperfine interactions play a crucial role in two-photon EB processes in 229Th3+ ions, achieving ultra-high fidelity isomeric population transfer via a STIRAP scheme [1]. However, by performing a full calculation that incorporates the complete hyperfine structure, we reveal that the hyperfine splitting in the isomeric 7p1/2 manifold significantly degrades the excitation probability by disrupting the two-photon resonance condition. To overcome this limitation, we propose to combine magic wavelength with quantum interference effects to effectively restoring high-fidelity isomeric excitation.

	[[Category: Quantum Technology Workshop 2026]]		[[Category: Quantum Technology Workshop 2026]]

Belzig, Wolfgang

Mahnsoo.Choi — Tue, 22 Sep 2026 00:45:46 GMT

Topological Superconductivity in Synthetic Dimensions

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-==Topological Superconductivity in Synthetic Dimensions==
+==Contributions==
+* [[Topological Superconductivity in Synthetic Dimensions]]
 [[Category: Quantum Technology Workshop 2026]]

Topological Superconductivity in Synthetic Dimensions

Mahnsoo.Choi — Tue, 22 Sep 2026 00:45:43 GMT

Created page with "* Speaker: Wolfgang Belzig (Department of Physics, University of Konstanz, 78567 Konstanz, Germany) * Event: Quantum Technology Workshop 2026 * {{Media/Button|QTW2026-Belzig.pdf|Slides (PDF)}} Superconductivity is a macroscopic quantum phenomenon characterized by a complex order parameter that has both an amplitude and a phase. Coupling multiple superconductors introduces additional phase parameters that can be considered synthetic dimensions. T..."

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* Speaker: [[Belzig, Wolfgang|Wolfgang Belzig]] (Department of Physics, University of Konstanz, 78567 Konstanz, Germany)
* Event: [[Quantum Technology Workshop 2026]]
* {{Media/Button|QTW2026-Belzig.pdf|Slides (PDF)}}

Superconductivity is a macroscopic quantum phenomenon characterized by a complex order parameter that has both an amplitude and a phase. Coupling multiple superconductors introduces additional phase parameters that can be considered synthetic dimensions. The phases control quantum states in such systems, which can be considered quantum objects living in synthetic dimensions. For example, topological objects such as Weyl singularities exist only in three dimensions and offer a route toward novel quantum states that are topologically protected. In this talk, I will explain the basics of the underlying microscopic process, Andreev reflection, which leads to phase-dependent Andreev bound states. These topological states are of fundamental interest because they can host Weyl nodes, store robust quantum information, and realize more exotic topologies. I will present examples and discuss the current state of experimental research. Besides their fundamental importance, these states offer new perspectives for superconducting quantum bits.

[1] R. L. Klees, G. Rastelli, J. C. Cuevas, and W. Belzig, Microwave spectroscopy reveals the quantum geometric tensor of topological Josephson matter, Phys. Rev. Lett. 124, 197002 (2020)

[2] H. Weisbrich, R.L. Klees, G. Rastelli, and W. Belzig, Second Chern Number and Non-Abelian Berry Phase in Superconducting Systems, PRX Quantum 2, 010310 (2021).

[3] M. Coraiola, D. Z. Haxell, D. Sabonis, H. Weisbrich, A. E. Svetogorov, M. Hinderling, S. C. ten Kate, E. Cheah, F. Krizek, R. Schott, W. Wegscheider, J. C. Cuevas, W. Belzig, and F. Nichele, Phase-engineering the Andreev band structure of a three-terminal Josephson junction, Nat. Commun. 14, 6784 (2023).

[4] D. C. Ohnmacht, V. Wilhelm, H. Weisbrich, W. Belzig, Non-hermitian topology in multiterminal superconducting junctions, Phys. Rev. Lett. 134, 156601 (2025).

[5] T. Antonelli, M. Coraiola, D. C. Ohnmacht, A. E. Svetogorov, D. Sabonis, S. C. ten Kate, E. Cheah, F. Krizek, R. Schott, J. C. Cuevas, W. Belzig, W. Wegscheider, F. Nichele, Exploring the energy spectrum of a four-terminal Josephson junction: Towards topological Andreev band structures, Phys. Rev. X 15, 031066 (2025).

[[Category: Quantum Technology Workshop 2026]]
[[Category: Talks]]

Fang, Yinan

Mahnsoo.Choi — Tue, 22 Sep 2026 00:44:39 GMT

Subgap modes in two-dimensional magnetic Josephson junctions

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	[[Category: Speakers]]		[[Category: Speakers]]

	==~~Subgap modes in two-dimensional magnetic Josephson junctions~~==		==Contributions==
			* [[Subgap modes in two-dimensional magnetic Josephson junctions]]
	* ~~Speaker:~~ [[~~Fang, Yinan\|Fang Yinan]] (Yunnan University, China)~~
	* Event: [[Quantum Technology Workshop 2026]]
	* {{Media/Button\|QTW2026-Fang.pdf\|Slides (PDF)}}

	~~Interplay of different orders~~ in mesoscopic magnetic structures near superconducting interfaces can induce rich phenomena ranging from the proximity effect to the topological superconductor. In this talk, we focus on Josephson junctions consisting of two s-~~wave paired superconductors that interrupted by a ferromagnetic thin layer. In contrast to the usual~~ Josephson junctions where the quasi-particle mainly tunnels through the quasi-1D transport channel, in a 2D junction where the transverse motion of the quasi-particle along the junction interface becomes important, we found a parameter-induced flat-dispersion in subgap modes due to a competition of the proximity effect and the ferromagnetic spin-splitting. This flat quasi-particle dispersion can be utilized for wavefunction switching for multi-domain structures thus opens up potential applications in spintronics.

	[1] ~~Yinan Fang, Seungju Han, Stefano Chesi, and Mahn-Soo Choi, Phys. Rev. B 107, 115114 (2023).~~

	[[Category: Quantum Technology Workshop 2026]]		[[Category: Quantum Technology Workshop 2026]]

Subgap modes in two-dimensional magnetic Josephson junctions

Mahnsoo.Choi — Tue, 22 Sep 2026 00:44:36 GMT

Created page with "* Speaker: Fang Yinan (Yunnan University, China) * Event: Quantum Technology Workshop 2026 * {{Media/Button|QTW2026-Fang.pdf|Slides (PDF)}} Interplay of different orders in mesoscopic magnetic structures near superconducting interfaces can induce rich phenomena ranging from the proximity effect to the topological superconductor. In this talk, we focus on Josephson junctions consisting of two s-wave paired superconductors that interrupted by a ferroma..."

New page

* Speaker: [[Fang, Yinan|Fang Yinan]] (Yunnan University, China)
* Event: [[Quantum Technology Workshop 2026]]
* {{Media/Button|QTW2026-Fang.pdf|Slides (PDF)}}

Interplay of different orders in mesoscopic magnetic structures near superconducting interfaces can induce rich phenomena ranging from the proximity effect to the topological superconductor. In this talk, we focus on Josephson junctions consisting of two s-wave paired superconductors that interrupted by a ferromagnetic thin layer. In contrast to the usual Josephson junctions where the quasi-particle mainly tunnels through the quasi-1D transport channel, in a 2D junction where the transverse motion of the quasi-particle along the junction interface becomes important, we found a parameter-induced flat-dispersion in subgap modes due to a competition of the proximity effect and the ferromagnetic spin-splitting. This flat quasi-particle dispersion can be utilized for wavefunction switching for multi-domain structures thus opens up potential applications in spintronics.

[1] Yinan Fang, Seungju Han, Stefano Chesi, and Mahn-Soo Choi, Phys. Rev. B 107, 115114 (2023).

[[Category: Quantum Technology Workshop 2026]]
[[Category: Talks]]

Tang, Gaoming

Mahnsoo.Choi — Tue, 22 Sep 2026 00:43:46 GMT

Transverse thermophotovoltaics

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	[[Category: Speakers]]		[[Category: Speakers]]

	==~~Transverse thermophotovoltaics~~==		==Contributions==
			* [[Transverse thermophotovoltaics]]
	* ~~Speaker:~~ [[~~Tang, Gaoming\|Gaoming Tang~~]] ~~(Graduate School of Chinese Academy of Engineering Physics, China)~~
	* Event: [[Quantum Technology Workshop 2026]]
	* {{Media/Button\|QTW2026-Tang.pdf\|Slides (PDF)}}

	Transverse thermophotovoltaics has been conceptually proposed as a paradigm distinct from conventional junction-based photovoltaics. The talk will introduce a microscopic formalism of this effect in which a transverse electric current emerges in a two dimensional metal sheet via nonreciprocal surface plasmon polaritons driven by near-field thermal radiation. This theoretical formalism incorporates the electron-photon interaction by integrating electronic transition factor governed by energy-momentum conservation, the photon flux factor encoding the nonreciprocal surface modes, and their directional coupling. Transverse thermophotovoltaics opens new avenues for active nanoscale thermal energy conversion. Furthermore, I will extend this framework to the photonic spin Seebeck effect in a similar setup, demonstrating how Rashba spin-orbit coupling in an electron-doped transition metal dichalcogenide monolayer converts circularly polarized thermal photons into electronic spin to induce a spin current.

	[[Category: Quantum Technology Workshop 2026]]		[[Category: Quantum Technology Workshop 2026]]

Transverse thermophotovoltaics

Mahnsoo.Choi — Tue, 22 Sep 2026 00:43:43 GMT

Created page with "* Speaker: Gaoming Tang (Graduate School of Chinese Academy of Engineering Physics, China) * Event: Quantum Technology Workshop 2026 * {{Media/Button|QTW2026-Tang.pdf|Slides (PDF)}} Transverse thermophotovoltaics has been conceptually proposed as a paradigm distinct from conventional junction-based photovoltaics. The talk will introduce a microscopic formalism of this effect in which a transverse electric current emerges in a two dimensional metal..."

New page

* Speaker: [[Tang, Gaoming|Gaoming Tang]] (Graduate School of Chinese Academy of Engineering Physics, China)
* Event: [[Quantum Technology Workshop 2026]]
* {{Media/Button|QTW2026-Tang.pdf|Slides (PDF)}}

Transverse thermophotovoltaics has been conceptually proposed as a paradigm distinct from conventional junction-based photovoltaics. The talk will introduce a microscopic formalism of this effect in which a transverse electric current emerges in a two dimensional metal sheet via nonreciprocal surface plasmon polaritons driven by near-field thermal radiation. This theoretical formalism incorporates the electron-photon interaction by integrating electronic transition factor governed by energy-momentum conservation, the photon flux factor encoding the nonreciprocal surface modes, and their directional coupling. Transverse thermophotovoltaics opens new avenues for active nanoscale thermal energy conversion. Furthermore, I will extend this framework to the photonic spin Seebeck effect in a similar setup, demonstrating how Rashba spin-orbit coupling in an electron-doped transition metal dichalcogenide monolayer converts circularly polarized thermal photons into electronic spin to induce a spin current.

[[Category: Quantum Technology Workshop 2026]]
[[Category: Talks]]

Few-Photon Bound States in the Continuum

Mahnsoo.Choi — Tue, 22 Sep 2026 00:42:46 GMT

Created page with "* Speaker: Yue Chang (Beijing Academy of Quantum Information Science, China) * Event: Quantum Technology Workshop 2026 * {{Media/Button|QTW2026-Yue.pdf|Slides (PDF)}} Bound states in the continuum (BICs) can confine photonic excitations in open systems without relying on conventional cavities or photonic band gaps, making them promising for long-lived quantum storage and few-photon control. In this talk, I will present our recent work on single- and t..."

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* Speaker: [[Chang, Yue|Yue Chang]] (Beijing Academy of Quantum Information Science, China)
* Event: [[Quantum Technology Workshop 2026]]
* {{Media/Button|QTW2026-Yue.pdf|Slides (PDF)}}

Bound states in the continuum (BICs) can confine photonic excitations in open systems without relying on conventional cavities or photonic band gaps, making them promising for long-lived quantum storage and few-photon control. In this talk, I will present our recent work on single- and two-photon BICs. For single-photon BICs, we develop a capture–reshape–release protocol based on temporal control of a giant atom coupled to a waveguide. For two-photon states, we establish a no-go theorem for interaction-active BICs supported by a single emitter. We then investigate two-photon quasi-BICs in giant-atom systems and determine how their decay rates scale with the system parameters.

[[Category: Quantum Technology Workshop 2026]]
[[Category: Talks]]

Chang, Yue

Mahnsoo.Choi — Tue, 22 Sep 2026 00:42:43 GMT

Few-Photon Bound States in the Continuum

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	[[Category: Speakers]]		[[Category: Speakers]]

	==Few-Photon Bound States in the Continuum==		==Contributions==
			* [[Few-Photon Bound States in the Continuum]]
	* Speaker: [[Chang, Yue\|Yue Chang]] (Beijing Academy of Quantum Information Science, China)
	* Event: [[Quantum Technology Workshop 2026]]
	* {{Media/Button\|QTW2026-Yue.pdf\|Slides (PDF)}}

	Bound states in the continuum (BICs) can confine photonic excitations in open systems without relying on conventional cavities or photonic band gaps, making them promising for long-lived quantum storage and few-photon control. In this talk, I will present our recent work on single- and two-photon BICs. For single-photon BICs, we develop a capture–reshape–release protocol based on temporal control of a giant atom coupled to a waveguide. For two-photon states, we establish a no-go theorem for interaction-active BICs supported by a single emitter. We then investigate two-photon quasi-BICs in giant-atom systems and determine how their decay rates scale with the system parameters.

	[[Category: Quantum Technology Workshop 2026]]		[[Category: Quantum Technology Workshop 2026]]

Maximal coherence of quantum measurement and the resource theory of sharpness

Mahnsoo.Choi — Tue, 22 Sep 2026 00:41:44 GMT

Created page with "* Speaker: Kyunghyun Baek (Yonsei University, Korea) * Event: Quantum Technology Workshop 2026 * {{Media/Button|QTW2026-Baek.pdf|Slides (PDF)}} A resource theory of quantum measurement can be addressed in terms of quantum coherence and measurement sharpness, respectively. The former analyzes the off-diagonal structure of POVM elements in a predetermined basis while the latter analyzes the deviation from trivial, state-independent, measurements...."

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* Speaker: [[Baek, Kyunghyun | Kyunghyun Baek]] (Yonsei University, Korea)
* Event: [[Quantum Technology Workshop 2026]]
* {{Media/Button|QTW2026-Baek.pdf|Slides (PDF)}}

A resource theory of quantum measurement can be addressed in terms of quantum coherence and measurement sharpness, respectively. The former analyzes the off-diagonal structure of POVM elements in a predetermined basis while the latter analyzes the deviation from trivial, state-independent, measurements. In this talk, I will review the framework of quantum resource theories, and introduce a direct connection between the two resource theories by identifying measurement sharpness as the maximal coherence that is achievable under all possible unitary changes of the reference basis. More specifically, for a broad class of POVMs whose elements share a common eigenbasis, we show that the maximal distance-based coherence of measurement coincides exactly with the corresponding distance-based sharpness monotone. We further extend this equivalence, with element-additive distances, to POVMs whose elements admit a common mutually unbiased basis structure. These results provide a measurement-theoretic analogue of the maximal-coherence and purity correspondence for quantum states.

[[Category: Quantum Technology Workshop 2026]]
[[Category: Talks]]

Baek, Kyunghyun

Mahnsoo.Choi — Tue, 22 Sep 2026 00:41:40 GMT

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	Kyunghyun Baek studied physics at Sogang University, where he received his B.S. in 2012 and his Ph.D. in 2018 with a thesis on entropic uncertainty relations, unsharpness, and non-Gaussianity. He then worked as a postdoctoral researcher at Texas A&M University at Qatar and the Asia Pacific Center for Theoretical Physics, and later joined the Korea Institute for Advanced Study as a Research Fellow. From 2022 to 2024, he was a Senior Researcher at the Electronics and Telecommunications Research Institute. In 2024, he became Assistant Professor at Yonsei University, Institute for Convergence Research and Education in Advanced Technology, and Head of the Center for Quantum Computing Technology Support in Incheon. His research focuses on quantum information theory, quantum measurement, quantum resource theories, and near-term quantum algorithms, including variational quantum algorithms, quantum simulation, and quantum computing applications.		Kyunghyun Baek studied physics at Sogang University, where he received his B.S. in 2012 and his Ph.D. in 2018 with a thesis on entropic uncertainty relations, unsharpness, and non-Gaussianity. He then worked as a postdoctoral researcher at Texas A&M University at Qatar and the Asia Pacific Center for Theoretical Physics, and later joined the Korea Institute for Advanced Study as a Research Fellow. From 2022 to 2024, he was a Senior Researcher at the Electronics and Telecommunications Research Institute. In 2024, he became Assistant Professor at Yonsei University, Institute for Convergence Research and Education in Advanced Technology, and Head of the Center for Quantum Computing Technology Support in Incheon. His research focuses on quantum information theory, quantum measurement, quantum resource theories, and near-term quantum algorithms, including variational quantum algorithms, quantum simulation, and quantum computing applications.

	==~~Maximal coherence of quantum measurement and the resource theory of sharpness~~==		==Contributions==
			* [[Maximal coherence of quantum measurement and the resource theory of sharpness]]
	* ~~Speaker:~~ [[~~Baek, Kyunghyun \| Kyunghyun Baek]] (Yonsei University, Korea)~~
	* Event: [[Quantum Technology Workshop 2026]]
	* {{Media/Button\|QTW2026-Baek.pdf\|Slides (PDF)}}

	~~A resource theory~~ of quantum measurement can be addressed in terms of quantum coherence and measurement sharpness, respectively. The former analyzes the off-diagonal structure of POVM elements in a predetermined basis while the latter analyzes the deviation from trivial, state-independent, measurements. In this talk, I will review the framework of quantum resource theories, and ~~introduce a direct connection between~~ the ~~two~~ resource ~~theories by identifying measurement sharpness as the maximal coherence that is achievable under all possible unitary changes~~ of the reference basis. More specifically, for a broad class of POVMs whose elements share a common eigenbasis, we show that the maximal distance-based coherence of measurement coincides exactly with the corresponding distance-based sharpness monotone. We further extend this equivalence, with element-additive distances, to POVMs whose elements admit a common mutually unbiased basis structure. These results provide a measurement-theoretic analogue of the maximal-coherence and purity correspondence for quantum states.

	~~[[Category: Quantum Technology Workshop 2026~~]]

	~~==Other Contributions==~~
	* [[Variational Quantum Eigensolver]]		* [[Variational Quantum Eigensolver]]

	[[Category:2023 Special Summer Internship on VQA Speakers]]		[[Category:2023 Special Summer Internship on VQA Speakers]]
	[[Category:Speakers]]		[[Category:Speakers]]

Li, Jiahui

Mahnsoo.Choi — Tue, 22 Sep 2026 00:40:13 GMT

Spin fluctuations in the dissipative phase transitions of the quantum Rabi model

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	[[Category: Speakers]]		[[Category: Speakers]]

	==Spin fluctuations in the dissipative phase transitions of the quantum Rabi model==		==Contributions==
			* [[Spin fluctuations in the dissipative phase transitions of the quantum Rabi model]]
	* Speaker: [[Li, Jiahui\|Jiahui Li]] ~~(Henan University, China)~~
	* Event: [[Quantum Technology Workshop 2026]]
	* {{Media/Button\|QTW2026-Li.pdf\|Slides (PDF)}}

	We will present our research on dissipative phase transitions in the quantum Rabi model in this report. We highlight that significant spin fluctuations persist in the system’s stationary state, which have important consequences for the phase diagram and critical properties. In the second-order phase transition, there is a significant suppression of the order parameter and the appearance of non-universal factors, which directly reflect the spin populations. Furthermore, upon entering a parameter regime where mean-field theory predicts a tricritical phase, we find a first-order phase transition due to the unexpected collapse of superradiance. An accurate and physically transparent description going beyond mean-field theory is established by combining exact numerical simulations, the cumulant expansion, and analytical approximations based on reduced master equations and an effective equilibrium theory.

	[[Category: Quantum Technology Workshop 2026]]		[[Category: Quantum Technology Workshop 2026]]

Hwang, Myung-Joong

Mahnsoo.Choi — Tue, 22 Sep 2026 00:39:44 GMT

Contributions

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	==Contributions==		==Contributions==
	* [[Nonreciprocal and Geometric Frustration in Dissipative Quantum Spins]]		* [[Nonreciprocal and Geometric Frustration in Dissipative Quantum Spins]]

	~~[[Category: Quantum Technology Workshop 2026]]~~

	~~==Other Contributions==~~
	* [[Quantum phase transition and universal dynamics in the Rabi model]]		* [[Quantum phase transition and universal dynamics in the Rabi model]]

	[[Category:Speakers]]		[[Category:Speakers]]
	[[Category:Old Members]]		[[Category:Old Members]]

Spin fluctuations in the dissipative phase transitions of the quantum Rabi model

Mahnsoo.Choi — Tue, 22 Sep 2026 00:38:45 GMT

Created page with "* Speaker: Jiahui Li (Henan University, China) * Event: Quantum Technology Workshop 2026 * {{Media/Button|QTW2026-Li.pdf|Slides (PDF)}} We will present our research on dissipative phase transitions in the quantum Rabi model in this report. We highlight that significant spin fluctuations persist in the system’s stationary state, which have important consequences for the phase diagram and critical properties. In the second-order phase transition, ther..."

New page

* Speaker: [[Li, Jiahui|Jiahui Li]] (Henan University, China)
* Event: [[Quantum Technology Workshop 2026]]
* {{Media/Button|QTW2026-Li.pdf|Slides (PDF)}}

We will present our research on dissipative phase transitions in the quantum Rabi model in this report. We highlight that significant spin fluctuations persist in the system’s stationary state, which have important consequences for the phase diagram and critical properties. In the second-order phase transition, there is a significant suppression of the order parameter and the appearance of non-universal factors, which directly reflect the spin populations. Furthermore, upon entering a parameter regime where mean-field theory predicts a tricritical phase, we find a first-order phase transition due to the unexpected collapse of superradiance. An accurate and physically transparent description going beyond mean-field theory is established by combining exact numerical simulations, the cumulant expansion, and analytical approximations based on reduced master equations and an effective equilibrium theory.

[[Category: Quantum Technology Workshop 2026]]
[[Category: Talks]]

Hwang, Myung-Joong

Mahnsoo.Choi — Tue, 22 Sep 2026 00:37:53 GMT

Nonreciprocal and Geometric Frustration in Dissipative Quantum Spins

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	Myung-Joong Hwang is an Associate Professor of Physics at Duke Kunshan University in China and an Associate Professor of Practice at Duke University in U.S. His research focuses on uncovering novel quantum phenomena and designing controlled quantum systems based on superconducting circuits and AMO systems such as ion-traps and cold atoms with optical cavities and harnessing them for quantum computing and quantum sensing. He has a Ph.D in physics from Pohang University of Science and Technology, South Korea. Before joining Duke Kunshan, he was a postdoctoral researcher at the Institute of Theoretical Physics at Ulm University, Germany.		Myung-Joong Hwang is an Associate Professor of Physics at Duke Kunshan University in China and an Associate Professor of Practice at Duke University in U.S. His research focuses on uncovering novel quantum phenomena and designing controlled quantum systems based on superconducting circuits and AMO systems such as ion-traps and cold atoms with optical cavities and harnessing them for quantum computing and quantum sensing. He has a Ph.D in physics from Pohang University of Science and Technology, South Korea. Before joining Duke Kunshan, he was a postdoctoral researcher at the Institute of Theoretical Physics at Ulm University, Germany.

	==Nonreciprocal and Geometric Frustration in Dissipative Quantum Spins==		==Contributions==
			* [[Nonreciprocal and Geometric Frustration in Dissipative Quantum Spins]]
	* Speaker: [[Hwang, Myung-Joong\|Myung-Joong Hwang]] (Duke Kunshan University, China)
	* Event: [[Quantum Technology Workshop 2026]]
	* {{Media/Button\|QTW2026-Hwang.pdf\|Slides (PDF)}}

	Abstract: Nonreciprocal interactions create conflicting dynamical objectives that cannot be simultaneously satisfied, leading to nonreciprocal frustration. Geometric frustration, on the other hand, arises when conflicting static objectives in energy minimization cannot be satisfied. In this work, we show that nonreciprocal interaction among three collective quantum spins, mediated by a damped cavity, induces not only nonreciprocal frustration, intrinsic to nonreciprocity, but also geometric frustration with a remarkable robustness against disorder. It therefore ensures that the accidental degeneracy for steady states remains intact even when the system is perturbed away from a fine-tuned point of enhanced symmetry, in sharp contrast to the equilibrium case. Leveraging this finding, we identify a nonreciprocal phase transition driven by both geometric and nonreciprocal frustration. It gives rise to a time-dependent state, which shows chiral dynamics along a geometry shaped by the geometric frustration and dynamically restores the broken discrete symmetries. Moreover, it constitutes a time-crystalline order, with multiple harmonics set by an emergent time scale that exhibits critical slowing down. We discuss the potential experimental realizations using a three-component spinor BEC-cavity system, where our finding manifests as a geometric frustration in the structural phase transition and chiral dynamics of the frustrated self-organized BECs. We demonstrate the feasibility of experimental observation under realistic conditions.

	[[Category: Quantum Technology Workshop 2026]]		[[Category: Quantum Technology Workshop 2026]]


	==Other Contributions==		==Other Contributions==

Nonreciprocal and Geometric Frustration in Dissipative Quantum Spins

Mahnsoo.Choi — Tue, 22 Sep 2026 00:37:45 GMT

Created page with "* Speaker: Myung-Joong Hwang (Duke Kunshan University, China) * Event: Quantum Technology Workshop 2026 * {{Media/Button|QTW2026-Hwang.pdf|Slides (PDF)}} Abstract: Nonreciprocal interactions create conflicting dynamical objectives that cannot be simultaneously satisfied, leading to nonreciprocal frustration. Geometric frustration, on the other hand, arises when conflicting static objectives in energy minimization cannot be satisfied. In this w..."

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* Speaker: [[Hwang, Myung-Joong|Myung-Joong Hwang]] (Duke Kunshan University, China)
* Event: [[Quantum Technology Workshop 2026]]
* {{Media/Button|QTW2026-Hwang.pdf|Slides (PDF)}}

Abstract: Nonreciprocal interactions create conflicting dynamical objectives that cannot be simultaneously satisfied, leading to nonreciprocal frustration. Geometric frustration, on the other hand, arises when conflicting static objectives in energy minimization cannot be satisfied. In this work, we show that nonreciprocal interaction among three collective quantum spins, mediated by a damped cavity, induces not only nonreciprocal frustration, intrinsic to nonreciprocity, but also geometric frustration with a remarkable robustness against disorder. It therefore ensures that the accidental degeneracy for steady states remains intact even when the system is perturbed away from a fine-tuned point of enhanced symmetry, in sharp contrast to the equilibrium case. Leveraging this finding, we identify a nonreciprocal phase transition driven by both geometric and nonreciprocal frustration. It gives rise to a time-dependent state, which shows chiral dynamics along a geometry shaped by the geometric frustration and dynamically restores the broken discrete symmetries. Moreover, it constitutes a time-crystalline order, with multiple harmonics set by an emergent time scale that exhibits critical slowing down. We discuss the potential experimental realizations using a three-component spinor BEC-cavity system, where our finding manifests as a geometric frustration in the structural phase transition and chiral dynamics of the frustrated self-organized BECs. We demonstrate the feasibility of experimental observation under realistic conditions.

[[Category: Quantum Technology Workshop 2026]]
[[Category: Talks]]

Park, Seung

Mahnsoo.Choi — Tue, 22 Sep 2026 00:36:54 GMT

Dual-channel multi-product formula

← Older revision		Revision as of 00:36, 22 September 2026
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	[[Category:Old Members]]		[[Category:Old Members]]

	==~~Dual-channel multi-product formula~~==		==Contributions==
			* [[Dual-channel multi-product formula]]
	* ~~Speaker:~~ [[~~Park, Seung\|Seung Park]] (Yongsei University, Korea)~~
	* Event: [[Quantum Technology Workshop 2026]]
	* {{Media/Button\|QTW2026-~~Park.pdf\|Slides (PDF)}}~~

	Product formula (PF) is a promising approach for simulating quantum systems on near-term digital quantum computers. Achieving a desired simulation precision typically requires a polynomially increasing number of Trotter steps, which remains challenging due to the limited capabilities of current quantum hardware. To alleviate this issue, algorithmic error-mitigation techniques such as the multi-product formula (MPF) have been introduced to suppress Trotter errors under restricted hardware resources. In this work, we propose a dual-channel MPF protocol that utilizes the average of a PF and its reversed-sequence counterpart without increasing circuit depth. Our method enables the target simulation precision to be reached with approximately half the circuit depth compared to conventional MPF schemes. This provides substantial error reduction on noisy hardware while implementing a well-conditioned MPF. We also demonstrate our algorithm through numerical simulations under a noise model, showing that our proposal achieves significantly smaller errors.

	~~[[Category: Quantum Technology Workshop 2026~~]]

Dual-channel multi-product formula

Mahnsoo.Choi — Tue, 22 Sep 2026 00:36:23 GMT

Created page with "* Speaker: Seung Park (Yongsei University, Korea) * Event: Quantum Technology Workshop 2026 * {{Media/Button|QTW2026-Park.pdf|Slides (PDF)}} Product formula (PF) is a promising approach for simulating quantum systems on near-term digital quantum computers. Achieving a desired simulation precision typically requires a polynomially increasing number of Trotter steps, which remains challenging due to the limited capabilities of current quantum hardware...."

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* Speaker: [[Park, Seung|Seung Park]] (Yongsei University, Korea)
* Event: [[Quantum Technology Workshop 2026]]
* {{Media/Button|QTW2026-Park.pdf|Slides (PDF)}}

Product formula (PF) is a promising approach for simulating quantum systems on near-term digital quantum computers. Achieving a desired simulation precision typically requires a polynomially increasing number of Trotter steps, which remains challenging due to the limited capabilities of current quantum hardware. To alleviate this issue, algorithmic error-mitigation techniques such as the multi-product formula (MPF) have been introduced to suppress Trotter errors under restricted hardware resources. In this work, we propose a dual-channel MPF protocol that utilizes the average of a PF and its reversed-sequence counterpart without increasing circuit depth. Our method enables the target simulation precision to be reached with approximately half the circuit depth compared to conventional MPF schemes. This provides substantial error reduction on noisy hardware while implementing a well-conditioned MPF. We also demonstrate our algorithm through numerical simulations under a noise model, showing that our proposal achieves significantly smaller errors.

[[Category: Quantum Technology Workshop 2026]]
[[Category: Talks]]

Dynamics of spiral magnetic order in an electrically-biased Kondo chain

Mahnsoo.Choi — Tue, 22 Sep 2026 00:35:16 GMT

Created page with "* Speaker: Stefano Chesi (Computational Science Research Center, China) * Event: Quantum Technology Workshop 2026 * {{Media/Button|QTW2026-Chesi.pdf|Slides (PDF)}} We analyze a one-dimensional system of localized magnetic moments coupled to itinerant electrons, which has been proposed, in conjunction with proximity-induced superconductivity, to host a self-organized topological phase. Here, we characterize the magnetic properties of this model in..."

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* Speaker: [[Chesi, Stefano|Stefano Chesi]] (Computational Science Research Center, China)
* Event: [[Quantum Technology Workshop 2026]]
* {{Media/Button|QTW2026-Chesi.pdf|Slides (PDF)}}

We analyze a one-dimensional system of localized magnetic moments coupled to itinerant electrons, which has been proposed, in conjunction with proximity-induced superconductivity, to host a self-organized topological phase. Here, we characterize the magnetic properties of this model in the absence of superconductivity, by employing a non-equilibrium description of the itinerant electrons, combined with an adiabatic approximation and a phenomenological damping term for the localized spin dynamics. In the equilibrium limit, our approach reveals a weak spatial modulation of the predicted spiral order (i.e., the specific magnetic texture behind topological superconductivity). This modulation stems from an electronic instability that drives the system towards a fully gapped state. The presence of a finite gap, rather than half-metallic chiral states, could potentially hinder the formation of the topological phase. Furthermore, upon applying a finite bias, we uncover a complex landscape of dynamical regimes. At low bias, we find a rigidly-rotating non-coplanar magnetic structure, which transitions to quasi-periodic dynamics and ultimately to chaos as the voltage increases. These phases yield distinct signatures in both charge and spin transport. For the rigidly-rotating state, we analyze the dependence of the rotation axis and frequency on system parameters, demonstrate the transport of spin polarization between the two contacts, and show that the spin dynamics slows down in the thermodynamic limit, where a static conical state persists to arbitrarily long times.

[[Category: Quantum Technology Workshop 2026]]
[[Category: Talks]]

Chesi, Stefano

Mahnsoo.Choi — Tue, 22 Sep 2026 00:35:07 GMT

Dynamics of spiral magnetic order in an electrically-biased Kondo chain

← Older revision		Revision as of 00:35, 22 September 2026
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	[[Category: Speakers]]		[[Category: Speakers]]

	==Dynamics of spiral magnetic order in an electrically-biased Kondo chain==		==Contributions==
			* [[Dynamics of spiral magnetic order in an electrically-biased Kondo chain]]
	* Speaker: [[Chesi, Stefano\|Stefano Chesi]] ~~(Computational Science Research Center, China)~~
	* Event: [[Quantum Technology Workshop 2026]]
	* {{Media/Button\|QTW2026-Chesi.pdf\|Slides (PDF)}}

	We analyze a one-dimensional system of localized magnetic moments coupled to itinerant electrons, which has been proposed, in conjunction with proximity-induced superconductivity, to host a self-organized topological phase. Here, we characterize the magnetic properties of this model in the absence of superconductivity, by employing a non-equilibrium description of the itinerant electrons, combined with an adiabatic approximation and a phenomenological damping term for the localized spin dynamics. In the equilibrium limit, our approach reveals a weak spatial modulation of the predicted spiral order (i.e., the specific magnetic texture behind topological superconductivity). This modulation stems from an electronic instability that drives the system towards a fully gapped state. The presence of a finite gap, rather than half-metallic chiral states, could potentially hinder the formation of the topological phase. Furthermore, upon applying a finite bias, we uncover a complex landscape of dynamical regimes. At low bias, we find a rigidly-rotating non-coplanar magnetic structure, which transitions to quasi-periodic dynamics and ultimately to chaos as the voltage increases. These phases yield distinct signatures in both charge and spin transport. For the rigidly-rotating state, we analyze the dependence of the rotation axis and frequency on system parameters, demonstrate the transport of spin polarization between the two contacts, and show that the spin dynamics slows down in the thermodynamic limit, where a static conical state persists to arbitrarily long times.


	[[Category: Quantum Technology Workshop 2026]]		[[Category: Quantum Technology Workshop 2026]]

Quantum Technology Workshop 2026

Mahnsoo.Choi — Tue, 22 Sep 2026 00:30:07 GMT

Program

Fermionic Gaussian Simulation: Applications and Beyond

Mahnsoo.Choi — Mon, 21 Sep 2026 00:32:59 GMT

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	[[Category: Quantum Technology Workshop 2026]]		[[Category: Quantum Technology Workshop 2026]]
	[[Category: Talks]]		[[Category: Talks]]
	~~[[Category: Default]]~~

Quantum Technology Workshop 2026

Mahnsoo.Choi — Mon, 21 Sep 2026 00:32:39 GMT

Program

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	<dt>Day 2</dt>		<dt>Day 2</dt>
	<ul>		<ul>
	<li><b>09:00--09:45</b> [[Fermionic Gaussian Simulation: Applications and Beyond\|Choi, Mahn-Soo]] (Korea University, Korea)</li>		<li><b>09:00--09:45</b> [[Fermionic Gaussian Simulation: Applications and Beyond]] by [[Choi, Mahn-Soo]] (Korea University, Korea)</li>
	<li><b>10:00--10:45</b> [[Chesi, Stefano]] (Computational Science Research Center, China)</li>		<li><b>10:00--10:45</b> [[Chesi, Stefano]] (Computational Science Research Center, China)</li>
	<li><b>11:00--11:45</b> [[Park, Seung]] (Yongsei University, Korea)</li>		<li><b>11:00--11:45</b> [[Park, Seung]] (Yongsei University, Korea)</li>

Han, Seungju

Mahnsoo.Choi — Mon, 21 Sep 2026 00:31:30 GMT

Contributions

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	[[Category:Old Members]]		[[Category:Old Members]]

	==Josephson Parametric Amplification from Resonators to Traveling Waves==		==Contributions==
			* [[Josephson Parametric Amplification from Resonators to Traveling Waves]]

	* Speaker: [[Han, Seungju\|Suengju Han]] (Computational Science Research Center, China)		[[Category: Default]]
	* Event: [[Quantum Technology Workshop 2026]]
	* {{Media/Button\|QTW2026-Han.pdf\|Slides (PDF)}}

	~~Abstract~~
	Josephson parametric amplifiers (JPAs) provide near-quantum-limited amplification of microwave signals using the nonlinearity of Josephson junctions. In this talk, I will review the basic physics of JPAs, starting from resonator-based JPAs and extending to Josephson traveling-wave parametric amplifiers (JTWPAs). The talk will cover how Josephson nonlinearity leads to parametric amplification and introduce the concepts of wave mixing, phase matching, and dispersion engineering relevant to JTWPAs. Finally, some theoretical aspects of gain ripples and two-pump schemes in JTWPAs will be briefly discussed.

	[[Category: ~~Quantum Technology Workshop 2026~~]]

Josephson Parametric Amplification from Resonators to Traveling Waves

Mahnsoo.Choi — Mon, 21 Sep 2026 00:31:12 GMT

Created page with "* Speaker: Suengju Han (Computational Science Research Center, China) * Event: Quantum Technology Workshop 2026 * {{Media/Button|QTW2026-Han.pdf|Slides (PDF)}} Abstract Josephson parametric amplifiers (JPAs) provide near-quantum-limited amplification of microwave signals using the nonlinearity of Josephson junctions. In this talk, I will review the basic physics of JPAs, starting from resonator-based JPAs and extending to Josephson traveling-wave pa..."

New page

* Speaker: [[Han, Seungju|Suengju Han]] (Computational Science Research Center, China)
* Event: [[Quantum Technology Workshop 2026]]
* {{Media/Button|QTW2026-Han.pdf|Slides (PDF)}}

Abstract
Josephson parametric amplifiers (JPAs) provide near-quantum-limited amplification of microwave signals using the nonlinearity of Josephson junctions. In this talk, I will review the basic physics of JPAs, starting from resonator-based JPAs and extending to Josephson traveling-wave parametric amplifiers (JTWPAs). The talk will cover how Josephson nonlinearity leads to parametric amplification and introduce the concepts of wave mixing, phase matching, and dispersion engineering relevant to JTWPAs. Finally, some theoretical aspects of gain ripples and two-pump schemes in JTWPAs will be briefly discussed.

[[Category: Quantum Technology Workshop 2026]]
[[Category: Talks]]

Toward Scalable Two-Dimensional Fluxonium Quantum Processors: Challenges and Solutions

Mahnsoo.Choi — Mon, 21 Sep 2026 00:29:54 GMT

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	[[Category: Quantum Technology Workshop 2026]]		[[Category: Quantum Technology Workshop 2026]]
			[[Category: Talks]]

Topological States Beyond Translational Symmetry in a Trapped-Ion Quantum Simulator

Mahnsoo.Choi — Mon, 21 Sep 2026 00:29:25 GMT

← Older revision		Revision as of 00:29, 21 September 2026
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	[[Category: Quantum Technology Workshop 2026]]		[[Category: Quantum Technology Workshop 2026]]
			[[Category: Talks]]

Ren, Changliang

Mahnsoo.Choi — Mon, 21 Sep 2026 00:28:56 GMT

A Unified Framework for Sequential Quantum Correlation Sharing

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 [[Category: Old Members]]
-==A Unified Framework for Sequential Quantum Correlation Sharing==
+==Contributions==
 [[Category: Quantum Technology Workshop 2026]]

A Unified Framework for Sequential Quantum Correlation Sharing

Mahnsoo.Choi — Mon, 21 Sep 2026 00:28:52 GMT

Created page with "* Speaker: Changliang Ren (Department of Physics, Hunan Normal University, Changsha 410081, China) * Event: Quantum Technology Workshop 2026 * {{Media/Button|QTW2026-Ren.pdf|Slides (PDF)}} Quantum measurements not only extract information but also reshape quantum states through measurement backaction, thereby determining how quantum resources can be distributed and recycled. In this talk, recent progress on the sequential sharing of quantum corre..."

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* Speaker: [[Ren, Changliang|Changliang Ren]] (Department of Physics, Hunan Normal University, Changsha 410081, China)
* Event: [[Quantum Technology Workshop 2026]]
* {{Media/Button|QTW2026-Ren.pdf|Slides (PDF)}}

Quantum measurements not only extract information but also reshape quantum states through measurement backaction, thereby determining how quantum resources can be distributed and recycled. In this talk, recent progress on the sequential sharing of quantum correlations will be reviewed from the perspective of generalized quantum measurements and quantum instruments. Particular emphasis will be placed on Bell nonlocality, EPR steering, entanglement, network nonlocality, and contextuality under sequential and weak-measurement scenarios. Recent advances on complementarity-based correlation sharing and unified measurement frameworks beyond conventional POVM descriptions will also be discussed, highlighting how different Kraus structures govern resource dissipation, robustness, and quantum resource recycling in multipartite and sequential quantum information protocols.

[1] Z. Cai, C. Ren*, T. Feng, X. Zhou, J. Chen , A review of quantum correlation sharing: The recycling of quantum correlations triggered by quantum measurements, Physics Reports 1098, 1-53(2025).

[2] Z. Cai, J. Song,. A. Asadian, C. Ren*, Unified Framework for Quantum Resource Recycling via Instrument-Dependent Back-action, arXiv:2605.03513.

[3] Z. Cai, C. Ren*, Entanglement sharing in sequential quantum measurements revealed by complementarity, Phys. Rev. A, 113, 012217 (2026).

[4] C. Ren*, X. Liu, W. Hou, T. Feng and X. Zhou , Nonlocality sharing for a three-qubit system via multilateral sequential measurements, Phys. Rev. A 105, 052221 (2022).

[5] W. Hou, X. Liu, and C. Ren*, Network nonlocality sharing via weak measurements in the extended bilocal scenario, Phys. Rev. A 105, 042436 (2022).

[6] T. Feng, C, Ren*, Y, Tian, M, Luo, H, Shi, J, Chen, and X, Zhou, Observation of nonlocality sharing via not-so-weak measurements, Phys. Rev. A 102, 032220 (2020).

[[Category: Quantum Technology Workshop 2026]]
[[Category: Talks]]

Kim, Junki

Mahnsoo.Choi — Mon, 21 Sep 2026 00:27:15 GMT

Topological States Beyond Translational Symmetry in a Trapped-Ion Quantum Simulator

← Older revision		Revision as of 00:27, 21 September 2026
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	[[Category: Speakers]]		[[Category: Speakers]]

	==Topological States Beyond Translational Symmetry in a Trapped-Ion Quantum Simulator==		==Contributions==
			* [[Topological States Beyond Translational Symmetry in a Trapped-Ion Quantum Simulator]]
	* Speaker: [[Kim, Junki\|Junki, Kim]] ~~(Sungkyunkwan University, Korea)~~
	* Event: [[Quantum Technology Workshop 2026]]
	* {{Media/Button\|QTW2026-Kim.pdf\|Slides (PDF)}}

	Quantum simulators provide a rich experimental platform for exploring exotic quantum phenomena with a high degree of tunability. Beyond reproducing the physics of conventional materials, they enable the realization of synthetic Hamiltonians with symmetries different from those of naturally occurring systems, enriching the study of unconventional topological phenomena. In this talk, I will present our experimental study of topological behavior in the anisotropic quantum Rabi model (AQRM) using a trapped-ion quantum simulator. We prepare and characterize both boundary and bulk states and investigate their distinct topological properties. Unlike conventional lattice systems, the AQRM lacks translational symmetry, and its bulk states can exhibit localization similar to that of the boundary state. Nevertheless, topological observables, including chirality and spin–boson correlations, clearly distinguish the boundary state from the bulk states. We further reconstruct the phase-space distribution of the bosonic component of the boundary state, revealing pronounced nonclassical squeezing. These results demonstrate how highly controllable quantum simulators can provide access to topological phenomena beyond those typically encountered in conventional condensed-matter systems.

	[[Category: Quantum Technology Workshop 2026]]		[[Category: Quantum Technology Workshop 2026]]

Topological States Beyond Translational Symmetry in a Trapped-Ion Quantum Simulator

Mahnsoo.Choi — Mon, 21 Sep 2026 00:27:05 GMT

Created page with "* Speaker: Junki, Kim (Sungkyunkwan University, Korea) * Event: Quantum Technology Workshop 2026 * {{Media/Button|QTW2026-Kim.pdf|Slides (PDF)}} Quantum simulators provide a rich experimental platform for exploring exotic quantum phenomena with a high degree of tunability. Beyond reproducing the physics of conventional materials, they enable the realization of synthetic Hamiltonians with symmetries different from those of naturally occurring systems,..."

New page

* Speaker: [[Kim, Junki|Junki, Kim]] (Sungkyunkwan University, Korea)
* Event: [[Quantum Technology Workshop 2026]]
* {{Media/Button|QTW2026-Kim.pdf|Slides (PDF)}}

Quantum simulators provide a rich experimental platform for exploring exotic quantum phenomena with a high degree of tunability. Beyond reproducing the physics of conventional materials, they enable the realization of synthetic Hamiltonians with symmetries different from those of naturally occurring systems, enriching the study of unconventional topological phenomena. In this talk, I will present our experimental study of topological behavior in the anisotropic quantum Rabi model (AQRM) using a trapped-ion quantum simulator. We prepare and characterize both boundary and bulk states and investigate their distinct topological properties. Unlike conventional lattice systems, the AQRM lacks translational symmetry, and its bulk states can exhibit localization similar to that of the boundary state. Nevertheless, topological observables, including chirality and spin–boson correlations, clearly distinguish the boundary state from the bulk states. We further reconstruct the phase-space distribution of the bosonic component of the boundary state, revealing pronounced nonclassical squeezing. These results demonstrate how highly controllable quantum simulators can provide access to topological phenomena beyond those typically encountered in conventional condensed-matter systems.

[[Category: Quantum Technology Workshop 2026]]

Shi, Tao

Mahnsoo.Choi — Mon, 21 Sep 2026 00:26:11 GMT

Many-body Quantum Phases in Micro-wave Shielded Polar Molecules

← Older revision		Revision as of 00:26, 21 September 2026
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	[[Category: Speakers]]		[[Category: Speakers]]

	==Many-body Quantum Phases in Micro-wave Shielded Polar Molecules==		==Contributions==
			* [[Many-body Quantum Phases in Micro-wave Shielded Polar Molecules]]
	* Speaker: [[Shi, Tao\|Tao Shi]] ~~(Institute of Theoretical Physics, CAS, China)~~
	* Event: [[Quantum Technology Workshop 2026]]
	* {{Media/Button\|QTW2026-Shi.pdf\|Slides (PDF)}}

	abstract: We show that the effective interaction potential between microwave-shielded polar molecules consists of an anisotropic van der Waals-like shielding core and a modified dipolar interaction. This effective potential is validated by comparing its scattering cross-sections with those calculated using intermolecular potential involving all interaction channels. It is shown that a scattering resonance can be induced under microwave fields and a field-link tetramer bound state emerges. With the effective potential, we further study the Bardeen-Cooper-Schrieffer pairing, Bose-Einstein condensations, and supersolid phases in microwave-shielded molecular gas. We show the fermionic superfluid critical temperature drastically enhanced near the resonance, a formation of self-bound droplets with reduced condensate fraction resembling a magnified Helium 4, and a formation of supersolidity controlled by the microwave elliptical angle.

	[[Category: Quantum Technology Workshop 2026]]		[[Category: Quantum Technology Workshop 2026]]

Many-body Quantum Phases in Micro-wave Shielded Polar Molecules

Mahnsoo.Choi — Mon, 21 Sep 2026 00:25:58 GMT

Created page with "* Speaker: Tao Shi (Institute of Theoretical Physics, CAS, China) * Event: Quantum Technology Workshop 2026 * {{Media/Button|QTW2026-Shi.pdf|Slides (PDF)}} abstract: We show that the effective interaction potential between microwave-shielded polar molecules consists of an anisotropic van der Waals-like shielding core and a modified dipolar interaction. This effective potential is validated by comparing its scattering cross-sections with those calculated..."

New page

* Speaker: [[Shi, Tao|Tao Shi]] (Institute of Theoretical Physics, CAS, China)
* Event: [[Quantum Technology Workshop 2026]]
* {{Media/Button|QTW2026-Shi.pdf|Slides (PDF)}}

abstract: We show that the effective interaction potential between microwave-shielded polar molecules consists of an anisotropic van der Waals-like shielding core and a modified dipolar interaction. This effective potential is validated by comparing its scattering cross-sections with those calculated using intermolecular potential involving all interaction channels. It is shown that a scattering resonance can be induced under microwave fields and a field-link tetramer bound state emerges. With the effective potential, we further study the Bardeen-Cooper-Schrieffer pairing, Bose-Einstein condensations, and supersolid phases in microwave-shielded molecular gas. We show the fermionic superfluid critical temperature drastically enhanced near the resonance, a formation of self-bound droplets with reduced condensate fraction resembling a magnified Helium 4, and a formation of supersolidity controlled by the microwave elliptical angle.

[[Category: Quantum Technology Workshop 2026]]
[[Category: Talks]]

Jin, Lijing

Mahnsoo.Choi — Mon, 21 Sep 2026 00:24:11 GMT

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	Lijing Jin obtained his Ph.D. in theoretical physics through a joint training program between Université Grenoble Alpes and the French National Centre for Scientific Research (CNRS). He is currently the tech lead of the quantum chip design team at Guangdong–Hong Kong–Macao Greater Bay Area (Guangdong) Quantum Science Center, where his work focuses on the development of high-fidelity, scalable fluxonium-based superconducting quantum processors. His research interests include the theoretical modeling of superconducting quantum devices, electromagnetic simulation and validation methodologies, and the development of automated toolchains for quantum chip design. Previously, he was a postdoctoral researcher at the Beijing Computational Science Research Center, working on quantum optomechanics. He later joined Baidu Research as a senior researcher and led the quantum chip design team, where he was responsible for the development of superconducting quantum chips and related technologies.		Lijing Jin obtained his Ph.D. in theoretical physics through a joint training program between Université Grenoble Alpes and the French National Centre for Scientific Research (CNRS). He is currently the tech lead of the quantum chip design team at Guangdong–Hong Kong–Macao Greater Bay Area (Guangdong) Quantum Science Center, where his work focuses on the development of high-fidelity, scalable fluxonium-based superconducting quantum processors. His research interests include the theoretical modeling of superconducting quantum devices, electromagnetic simulation and validation methodologies, and the development of automated toolchains for quantum chip design. Previously, he was a postdoctoral researcher at the Beijing Computational Science Research Center, working on quantum optomechanics. He later joined Baidu Research as a senior researcher and led the quantum chip design team, where he was responsible for the development of superconducting quantum chips and related technologies.

			==Contributions==
			* [[Toward Scalable Two-Dimensional Fluxonium Quantum Processors: Challenges and Solutions]]

	[[Category: Speakers]]		[[Category: Speakers]]
	[[Category:Quantum Technology Workshop 2026]]		[[Category:Quantum Technology Workshop 2026]]

Bruder, Christoph

Mahnsoo.Choi — Mon, 21 Sep 2026 00:23:20 GMT

← Older revision		Revision as of 00:23, 21 September 2026
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	For more details, visit the [https://quantumtheory-bruder.physik.unibas.ch/en/ Web page of his research group] at the University of Basel.		For more details, visit the [https://quantumtheory-bruder.physik.unibas.ch/en/ Web page of his research group] at the University of Basel.

			==Contributions==
			* [[Quantum Synchronization]]

	[[Category:Speakers]]		[[Category:Speakers]]
	[[Category:Quantum Technology Workshop 2026]]		[[Category:Quantum Technology Workshop 2026]]

Lee, Minchul

Mahnsoo.Choi — Mon, 21 Sep 2026 00:22:33 GMT

Other Contributions

← Older revision		Revision as of 00:22, 21 September 2026
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	==Other Contributions==		==Other Contributions==
			* [[Effect of spin-orbit interaction on the quantum transport in quantum-dot Josephson junctions in the Kondo regime]]
	* [[Topological Insulators: Basics of Topological Insulators]]		* [[Topological Insulators: Basics of Topological Insulators]]

← Older revision		Revision as of 00:30, 22 September 2026
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	<ul>		<ul>
	<li><b>09:00--09:45</b> [[Fermionic Gaussian Simulation: Applications and Beyond]] by [[Choi, Mahn-Soo]] (Korea University, Korea)</li>		<li><b>09:00--09:45</b> [[Fermionic Gaussian Simulation: Applications and Beyond]] by [[Choi, Mahn-Soo]] (Korea University, Korea)</li>
	<li><b>10:00--10:45</b> [[Chesi, Stefano]] (Computational Science Research Center, China)</li>		<li><b>10:00--10:45</b> [[Dynamics of spiral magnetic order in an electrically-biased Kondo chain]] by [[Chesi, Stefano]] (Computational Science Research Center, China)</li>
	<li><b>11:00--11:45</b> [[Park, Seung]] (Yongsei University, Korea)</li>		<li><b>11:00--11:45</b> [[Dual-channel multi-product formula]] by [[Park, Seung]] (Yongsei University, Korea)</li>
	<li style="margin-top:5px; margin-bottom:5px;"><b>12:00--13:30</b> [https://www.bloomvista.co.kr/dining/bistrob Lunch Break]</li>		<li style="margin-top:5px; margin-bottom:5px;"><b>12:00--13:30</b> [https://www.bloomvista.co.kr/dining/bistrob Lunch Break]</li>
	<li style="margin-top:40px; margin-bottom:40px;"><b>13:30--18:00</b> [https://maps.app.goo.gl/nCesRM7fmpzYt7h99 Excursion]</li>		<li style="margin-top:40px; margin-bottom:40px;"><b>13:30--18:00</b> [https://maps.app.goo.gl/nCesRM7fmpzYt7h99 Excursion]</li>
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	<dt>Day 3</dt>		<dt>Day 3</dt>
	<ul>		<ul>
	<li><b>09:00--09:45</b> [[Hwang, Myung-Joong]] (Duke Kunshan University, China)</li>		<li><b>09:00--09:45</b> [[Nonreciprocal and Geometric Frustration in Dissipative Quantum Spins]] by [[Hwang, Myung-Joong]] (Duke Kunshan University, China)</li>
	<li><b>10:00--10:45</b> [[Li, Jiahui]] (Henan University, China)</li>		<li><b>10:00--10:45</b> [[Spin fluctuations in the dissipative phase transitions of the quantum Rabi model]] by [[Li, Jiahui]] (Henan University, China)</li>
	<li><b>11:00--11:45</b> [[Baek, Kyunghyun]] (Yonsei University, Korea)</li>		<li><b>11:00--11:45</b> [[Maximal coherence of quantum measurement and the resource theory of sharpness]] by [[Baek, Kyunghyun]] (Yonsei University, Korea)</li>

	<li style="margin-top:5px; margin-bottom:5px;"><b>12:00--13:30</b> [https://www.bloomvista.co.kr/dining/bistrob Lunch Break]</li>		<li style="margin-top:5px; margin-bottom:5px;"><b>12:00--13:30</b> [https://www.bloomvista.co.kr/dining/bistrob Lunch Break]</li>

	<li><b>13:30--14:15</b> [[Chang, Yue]] (Beijing Academy of QIS, China)</li>		<li><b>13:30--14:15</b> [[Few-Photon Bound States in the Continuum]] by [[Chang, Yue]] (Beijing Academy of QIS, China)</li>
	<li><b>14:30--15:15</b> [[Tang, Gaoming]] (Graduate School of CAEP, China)</li>		<li><b>14:30--15:15</b> [[Transverse thermophotovoltaics]] by [[Tang, Gaoming]] (Graduate School of CAEP, China)</li>
	<!--<li style="margin-top:5px; margin-bottom:5px;"><b>15:15--15:45</b> Coffee Break</li>-->		<!--<li style="margin-top:5px; margin-bottom:5px;"><b>15:15--15:45</b> Coffee Break</li>-->
	<li><b>15:30--16:15</b> [[Fang, Yinan]] (Yunnan University, China)</li>		<li><b>15:30--16:15</b> [[Subgap modes in two-dimensional magnetic Josephson junctions]] by [[Fang, Yinan]] (Yunnan University, China)</li>
	<li><b>16:30--17:15</b> [[Belzig, Wolfgang]] (University of Konstanz, Germany)</li>		<li><b>16:30--17:15</b> [[Topological Superconductivity in Synthetic Dimensions]] by [[Belzig, Wolfgang]] (University of Konstanz, Germany)</li>
	<li><b>17:30--18:15</b> [[Wang, Yingdan]] (Institute of Theoretical Physics, CAS, China)</li>		<li><b>17:30--18:15</b> [[Hyperfine electronic bridge for the excitation of the isomeric state in 229Th nucleus]] by [[Wang, Yingdan]] (Institute of Theoretical Physics, CAS, China)</li>
	~~<!--~~
	~~<li><b>17:30--18:15</b> [[Chen, Dongni]] (Shantou University, China)</li>~~
	-->
	<li style="margin-top:5px; margin-bottom:5px;"><b>18:15--18:20</b> Closing</li>		<li style="margin-top:5px; margin-bottom:5px;"><b>18:15--18:20</b> Closing</li>
	<li style="margin-top:5px;"><b>18:30--20:00</b> [https://www.bloomvista.co.kr/dining/bbqarea Dinner (Grill 316)]</li>		<li style="margin-top:5px;"><b>18:30--20:00</b> [https://www.bloomvista.co.kr/dining/bbqarea Dinner (Grill 316)]</li>