QCLab - User contributions [en]

Jeong, Se-Young

2019-09-20T06:18:42Z

Namanse23:

[[file:Jeong_SY.png|thumb|x300px|Prof. Jeong, Se-Young]]
Professor at pusan national Univ

==Education==
*1987.08. - 1990.06 독일 Koeln 대학 이학박사(응집물질 실험,결정물리학,결정학)

==Professional Experiences==
*2007.08. ~ 현재 단결정은행연구 소 소장
*2009.01. ~ 현재 융합물질거점센터(한국연구재단 연구소재은행) 센터장
*2005.03. ~ 현재 ㈜ MCLab 대표 이사
*2003.03. ~ 현재 부산대학교 나노과학기술대학 교수
*2014.07. - 2016.06. 부산대학교 나노과학기술대학 학장
*1998.03. ~ 현재 단결정은행 (한국연구재단 연구소재은행) 은행장

==Contributions==
* [[Atomic sputter epitaxy for metal single crystal thin film and its applications for Nanoscience and Photonics]]

[[Category:Speakers]]
[[Category:Condensed Matter Speakers]]

Yang, In-Sang

2019-09-20T06:14:52Z

Namanse23: Created page with "Prof. Yang, In-Sang(Ewha Womans Univ) Professor at Ewha Womans Univ ==Education== *Ph.D. University of Illinois at Urbana-Champaign, 1988 *M..."

[[file:Yang IS.jpg|thumb|x300px|Prof. Yang, In-Sang(Ewha Womans Univ)]]
Professor at Ewha Womans Univ

==Education==
*Ph.D. University of Illinois at Urbana-Champaign, 1988
*M.S. University of Illinois at Urbana-Champaign, 1986
*B.S. Department of Physics, Seoul National University, 1983

==Professional Experiences==
*Professor, Department of Physics and Division of nano-sciences, Ewha Womans University, 2000 - present
*Editor, Journal of the Korean Physical Society, 2005 - 2008
*Chief Secretary, Condensed Matter Division, Korean Physical Society, 2002 - 2004
*Visiting Research Associate Professor, Department of Physics, University of Illinois at Urbana-Champaign, 1998 - 2002
*Associate Professor, Department of Physics, Ewha Womans University, 1994 - 1999
*Assistant Professor, Department of Physics, Ewha Womans University, 1990 - 1994
*IBM Thomas J. Watson Research Center, Post-Doctor, 1988 - 1990

==Contributions==
* [[Raman study of spin excitations in hexagonal RMnO3]]

[[Category:Speakers]]
[[Category:Condensed Matter Speakers]]

Lim, Hyang-Tag

2019-09-20T06:04:17Z

Namanse23: Created page with "Dr. Lim, Hyang-Tag (KIST) Reseach Fellow at KIST ==Education== *B.S. Physics, Pohang University of Science and Technology , 2008 *Ph.D. Phy..."

[[file:Lim HT.jpg|thumb|x300px|Dr. Lim, Hyang-Tag (KIST)]]
Reseach Fellow at KIST

==Education==
*B.S. Physics, Pohang University of Science and Technology , 2008
*Ph.D. Physics, Pohang University of Science and Technology, 2015

==Professional Experiences==
*Senior Research Scientist, Center for Quantum Information, KIST, 2019 - present
*Post-doctoral Researcher, Institute for Quantum Electronics, ETH Zürich, Zürich, Switzerland, 2015 - 2018
*Post-doctoral Researcher, Department of Physics, Pohang University of Science and Technology (POSTECH), 2015

==Contributions==
* [[Towards quantum polaritonics: Strongly interacting polaritons]]

[[Category:Speakers]]
[[Category:Condensed Matter Speakers]]

Jeong, Se-Young

2019-09-19T06:03:19Z

Namanse23: Created page with "Prof. Jeong, Se-Young Professor ==Education== *1987.08. - 1990.06 독일 Koeln 대학 이학박사(응집물질 실험,결정물리학,결..."

[[file:Jeong_SY.png|thumb|x300px|Prof. Jeong, Se-Young]]
Professor

==Education==
*1987.08. - 1990.06 독일 Koeln 대학 이학박사(응집물질 실험,결정물리학,결정학)

==Professional Experiences==
*2007.08. ~ 현재 단결정은행연구 소 소장
*2009.01. ~ 현재 융합물질거점센터(한국연구재단 연구소재은행) 센터장
*2005.03. ~ 현재 ㈜ MCLab 대표 이사
*2003.03. ~ 현재 부산대학교 나노과학기술대학 교수
*2014.07. - 2016.06. 부산대학교 나노과학기술대학 학장
*1998.03. ~ 현재 단결정은행 (한국연구재단 연구소재은행) 은행장

==Contributions==
* [[Atomic sputter epitaxy for metal single crystal thin film and its applications for Nanoscience and Photonics]]

[[Category:Speakers]]
[[Category:Condensed Matter Speakers]]

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

2019-09-17T08:51:28Z

Namanse23:

[[file:Jeong_SY.png|thumb|x300px|Prof. Jeong, Se-Young]]
* Speaker: [[Jeong, Se-Young|Prof. Jeong, Se-Young]]
* Date: Wednesday October 02, 2019 05:00pm
* Place: Jungho Seminar Room

최근 구리 박막에 대한 관심도가 매우 커지고 있다. 그래핀과 같은 첨단 물질을 성장하는데 가장 필요한 기판 물질이기도 하고 소자 공정이 소형화 됨에 따라 금속의 결정성이 소자 특정에 미치는 영향을 학계와 산업계가 매우 깊게 인식하기 시작했기 때문이기도 하다. 2017년 Science에 발표된 논문은 “Nanocrystalline copper films are never flat” 이라는 제목으로 시작한다. 이 논문은 Nature Materials 의 News & Views에서 editor 가 특별 기사로 다루기도 했다. 우리가 금속박막을 다룸에 있어 완벽한 단결정을 만들 수 있다면 가장 이상적이겠지만 현실적으로 grain boundary의 존재를 무시할 수 없고 이러한 grain boundary에 의한 표면의 기울어짐은 원천적이며 특히 나노 박막에서는 이러한 defect들이, 특히 나노 science에서는 물성에 치명적인 영향을 준다는 것이 논문의 요지이다.

본 발표에서는 특별히 금속 박막의 성장을 위해 개발된 Atomic sputter epitaxy (ASE) 법에 대해 소개하고 이전의 다른 연구들과 상반되는 atomically ultra-flat 한 단결정 금속 박막의 특성을 소개하고자 한다. 본 발표에서 소개할 단결정 박막과 관련된 몇 가지 중요한 물리적 이슈는 다음과 같은 질문에서 시작된다. 첫째, 구리에서의 산화는 제어되는 것인가? 산화 없는 구리는 만들 수 없는가? 둘째, 구리의 색은 왜 동색인가? 구리의 색을 빨주노초파남보 색으로 구현할 수는 없는가? 셋째, 회색이나 검은색의 금속 표면색이 가능할까? CuO와 같은 산화에 의한 색이 아닌 금속 만으로 검게 만들 수 있을까 ? 넷째, 금속 단결정 박막의 두께를 수 nm 까지 얇게 했을 때 어느 경계에서 bulk와 2D의 특성이 나타날까? 아주 얇은 구리 박막은 여전히 금속일까? 다섯째, 구리 박막이 얇아지면 극저온에서의 특성이 달라지는 경계가 있을까? 여섯째, 반사도 100%인 금속이 존재할까? 이런 의문들은 금속에 있어서 매우 fundamental 한 질문들일 것이며 본 발표에서는 이러한 질문들에 대한 답을 드리고자 한다.

구리 박막의 최대 약점은 산화가 된다는 것인데 이 산화가 왜 일어나는 지는 대체적으로 잘 알려져 있는 듯 하지만 microscale에서의 현상은 아직 잘 알려져 있지 않다. 본 연구를 통해 우리는 3년이 지나도 산화되지 않는 단결정 구리 박막을 성장하였고 이러한 antioxidative characteristics에 대해 조사하였다. 산화 되지 않도록 물질을 만드는 것은 역으로 산화가 되는 메커니즘을 이해해야 하는 것과 같다. 이러한 산화에 대해 잘 이해함으로써 인위적인 산화를 잘 통제하여 구리 박막의 표면색을 360가지로 다르게 만들 수 있다. 여기에 더하여 빨주노초파남보의 총천연색 뿐 아니라 구리 박막의 표면을 잘 조절하면 검은 색을 띠는 일련의 acrobatic colour도 다양하게 구현할 수 있다. 이 acrobatic colour는 CuO 등의 산화물에서 기인한 것이 아니라 완변한 Cu(111)으로 이루어져 있어 여전히 완벽한 금속의 전도성을 가진다.

구리가 금(Au)을 대체할 수는 없다. 구리를 아무리 좋게 만들어도 금과 같은 귀금속으로 비싸게 팔 수는 없을 것이다. 그러나 학문적 측면에서 구리가 금보다 연구할 가치는 더 높다. 그 이유는 구리가 단결정이 되면 분야별로 예상치 못한 일들이 수없이 많이 일어나기 때문이다.

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

File:Jeong SY.png

2019-09-17T08:50:41Z

Namanse23:

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

2019-09-17T08:48:12Z

Namanse23: Created page with "Prof. Jeong, Se-Young * Speaker: Prof. Jeong, Se-Young * Date: Wednesday October 02, 2019 05:00pm * Place: Jungho Seminar..."

[[file:Nobody.jpg|thumb|x300px|Prof. Jeong, Se-Young]]
* Speaker: [[Jeong, Se-Young|Prof. Jeong, Se-Young]]
* Date: Wednesday October 02, 2019 05:00pm
* Place: Jungho Seminar Room

최근 구리 박막에 대한 관심도가 매우 커지고 있다. 그래핀과 같은 첨단 물질을 성장하는데 가장 필요한 기판 물질이기도 하고 소자 공정이 소형화 됨에 따라 금속의 결정성이 소자 특정에 미치는 영향을 학계와 산업계가 매우 깊게 인식하기 시작했기 때문이기도 하다. 2017년 Science에 발표된 논문은 “Nanocrystalline copper films are never flat” 이라는 제목으로 시작한다. 이 논문은 Nature Materials 의 News & Views에서 editor 가 특별 기사로 다루기도 했다. 우리가 금속박막을 다룸에 있어 완벽한 단결정을 만들 수 있다면 가장 이상적이겠지만 현실적으로 grain boundary의 존재를 무시할 수 없고 이러한 grain boundary에 의한 표면의 기울어짐은 원천적이며 특히 나노 박막에서는 이러한 defect들이, 특히 나노 science에서는 물성에 치명적인 영향을 준다는 것이 논문의 요지이다.

본 발표에서는 특별히 금속 박막의 성장을 위해 개발된 Atomic sputter epitaxy (ASE) 법에 대해 소개하고 이전의 다른 연구들과 상반되는 atomically ultra-flat 한 단결정 금속 박막의 특성을 소개하고자 한다. 본 발표에서 소개할 단결정 박막과 관련된 몇 가지 중요한 물리적 이슈는 다음과 같은 질문에서 시작된다. 첫째, 구리에서의 산화는 제어되는 것인가? 산화 없는 구리는 만들 수 없는가? 둘째, 구리의 색은 왜 동색인가? 구리의 색을 빨주노초파남보 색으로 구현할 수는 없는가? 셋째, 회색이나 검은색의 금속 표면색이 가능할까? CuO와 같은 산화에 의한 색이 아닌 금속 만으로 검게 만들 수 있을까 ? 넷째, 금속 단결정 박막의 두께를 수 nm 까지 얇게 했을 때 어느 경계에서 bulk와 2D의 특성이 나타날까? 아주 얇은 구리 박막은 여전히 금속일까? 다섯째, 구리 박막이 얇아지면 극저온에서의 특성이 달라지는 경계가 있을까? 여섯째, 반사도 100%인 금속이 존재할까? 이런 의문들은 금속에 있어서 매우 fundamental 한 질문들일 것이며 본 발표에서는 이러한 질문들에 대한 답을 드리고자 한다.

구리 박막의 최대 약점은 산화가 된다는 것인데 이 산화가 왜 일어나는 지는 대체적으로 잘 알려져 있는 듯 하지만 microscale에서의 현상은 아직 잘 알려져 있지 않다. 본 연구를 통해 우리는 3년이 지나도 산화되지 않는 단결정 구리 박막을 성장하였고 이러한 antioxidative characteristics에 대해 조사하였다. 산화 되지 않도록 물질을 만드는 것은 역으로 산화가 되는 메커니즘을 이해해야 하는 것과 같다. 이러한 산화에 대해 잘 이해함으로써 인위적인 산화를 잘 통제하여 구리 박막의 표면색을 360가지로 다르게 만들 수 있다. 여기에 더하여 빨주노초파남보의 총천연색 뿐 아니라 구리 박막의 표면을 잘 조절하면 검은 색을 띠는 일련의 acrobatic colour도 다양하게 구현할 수 있다. 이 acrobatic colour는 CuO 등의 산화물에서 기인한 것이 아니라 완변한 Cu(111)으로 이루어져 있어 여전히 완벽한 금속의 전도성을 가진다.

구리가 금(Au)을 대체할 수는 없다. 구리를 아무리 좋게 만들어도 금과 같은 귀금속으로 비싸게 팔 수는 없을 것이다. 그러나 학문적 측면에서 구리가 금보다 연구할 가치는 더 높다. 그 이유는 구리가 단결정이 되면 분야별로 예상치 못한 일들이 수없이 많이 일어나기 때문이다.

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

Raman study of spin excitations in hexagonal RMnO3

2019-09-17T08:44:15Z

Namanse23:

[[file:Yang_IS.jpg|thumb|x300px|Prof. Yang, In-Sang(Ewha Womans Univ)]]
* Speaker: [[Yang, In-Sang|Prof. Yang, In-Sang(Ewha Womans Univ)]]
* Date: Wednesday October 16, 2019 05:00pm
* Place: Jungho Seminar Room

===Abstract===

Spin excitations in the Mn-ion plane in the hexagonal RMnO3 (R= Y, rare earths) manganite systems can be selectively probed by the resonance Raman technique.
By choosing right resonance condition and appropriate polarization configuration, spin excitation scattering can be clearly observed, and the temperature dependence of the spin excitation scattering can be simple and powerful quantity for investigating spin-ordering as well as spin-reorientation transitions in RMnO3. Especially, the Raman method would be very helpful for investigating the weak spin-reorientation transitions by selectively probing the spin excitations in the Mn3+ ion sublattices, while leaving out the strong effects of paramagnetic moments of the rare earth ions.
In this talk, I would like to review a short history of our studies on the spin excitations in hexagonal RMnO3 observed by Raman spectroscopy, an optical method. I hope that my talk stimulates the audience and that some of the audience return insights regarding the nature of the spin excitations which are rather high in energy (~0.1 eV) compared to usual magnons (~ a few meV) observed by neutron scattering.

===References===
# Xiang-Bai Chen, Nguyen Thi Minh Hien, Kiok Han, Ji-Yeon Nam, Nguyen Thi Huyen, Seong-Il Shin, Xueyun Wang, S. W. Cheong, D. Lee, T. W. Noh, N. H. Sung, B. K. Cho, In-Sang Yang, Scientific Reports 5:13366, 2015.

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

File:Yang IS.jpg

2019-09-17T08:43:54Z

Namanse23:

Raman study of spin excitations in hexagonal RMnO3

2019-09-17T08:41:05Z

Namanse23: Created page with "Prof. Yang, In-Sang(Ewha Womans Univ) * Speaker: Prof. Yang, In-Sang(Ewha Womans Univ) * Date: Wednesday October 16, 2019 05..."

[[file:Nobody.jpg|thumb|x300px|Prof. Yang, In-Sang(Ewha Womans Univ)]]
* Speaker: [[Yang, In-Sang|Prof. Yang, In-Sang(Ewha Womans Univ)]]
* Date: Wednesday October 16, 2019 05:00pm
* Place: Jungho Seminar Room

===Abstract===

Spin excitations in the Mn-ion plane in the hexagonal RMnO3 (R= Y, rare earths) manganite systems can be selectively probed by the resonance Raman technique.
By choosing right resonance condition and appropriate polarization configuration, spin excitation scattering can be clearly observed, and the temperature dependence of the spin excitation scattering can be simple and powerful quantity for investigating spin-ordering as well as spin-reorientation transitions in RMnO3. Especially, the Raman method would be very helpful for investigating the weak spin-reorientation transitions by selectively probing the spin excitations in the Mn3+ ion sublattices, while leaving out the strong effects of paramagnetic moments of the rare earth ions.
In this talk, I would like to review a short history of our studies on the spin excitations in hexagonal RMnO3 observed by Raman spectroscopy, an optical method. I hope that my talk stimulates the audience and that some of the audience return insights regarding the nature of the spin excitations which are rather high in energy (~0.1 eV) compared to usual magnons (~ a few meV) observed by neutron scattering.

===References===
# Xiang-Bai Chen, Nguyen Thi Minh Hien, Kiok Han, Ji-Yeon Nam, Nguyen Thi Huyen, Seong-Il Shin, Xueyun Wang, S. W. Cheong, D. Lee, T. W. Noh, N. H. Sung, B. K. Cho, In-Sang Yang, Scientific Reports 5:13366, 2015.

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

Towards quantum polaritonics: Strongly interacting polaritons

2019-09-17T08:00:18Z

Namanse23:

[[file:Lim HT.jpg|thumb|x300px|Dr. Lim, Hyang-Tag (KIST)]]
* Speaker: [[Lim, Hyang-Tag|Dr. Lim, Hyang-Tag (KIST)]]
* Date: Wednesday October 30, 2019 05:00pm
* Place: Jungho Seminar Rooom

===Abstract===

Realization of a strongly interacting photonic systems is one of the essential issues in quantum optics. In solid-state systems, exciton-polaritons in micro-cavities, consisting of a cavity photon and a quantum well exciton, have interactions based on short-range exchange interaction between direct excitons. These interactions have lead to manifestation of a number of intriguing collective phenomena such as formation of spontaneous coherence, observation of vortex-antivortex pairs and dark solitons, and realization of polariton Josephson effect. However, a mean field approach has been successful to describe all these observations accurately. Increasing interactions between polaritons further is crucial to explore physics beyond mean-field description and to explore a new regime of strongly correlated photons.

In this presentation, I will discuss mainly two results. First, I will report that application of perpendicular electric and magnetic fields can generate a tunable artificial gauge potential for exciton-polaritons [1]. The strength and direction of the effected gauge potential are controlled electrically. Then, I will report that interaction between (dipolar) polaritons can be substantially increased by increasing size of the dipole moment of the polaritons. In our structure, one can tune the dipole size of dipolar polaritons by tuning the applied gate voltage, which controls growth directional electric fields. We observed more than factor of 5 enhancement in the interaction strength to linewidth ratio [2]. Together with strong polariton-polariton interactions and engineered polariton lattices, we believe that an artificial gauge field could play a key role in investigation of non-equilibrium dynamics of strongly correlated photons. In addition, dipolar polaritons could be used to demonstrate a polariton blockade effect, which could be the first demonstration of true quantum nature of polaritons beyond semi-classical description.

===References===

#H.-T. Lim*, E. Togan*, M. Kroner, J. Miguel-Sanchez, and A. Imamoglu, Nature Commun. 8, 14540 (2017).
#E. Togan*, H.-T. Lim*, S. Faelt, W. Wegscheider, and A. Imamoglu, Phys. Rev. Lett. 121, 227402 (2018).

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

File:Lim HT.jpg

2019-09-17T07:59:45Z

Namanse23:

Towards quantum polaritonics: Strongly interacting polaritons

2019-09-17T07:57:51Z

Namanse23: Created page with "Dr. Lim, Hyang-Tag (KIST) * Speaker: Dr. Lim, Hyang-Tag (KIST) * Date: Wednesday October 30, 2019 05:00pm * Place: Jungho S..."

[[file:Nobody.jpg|thumb|x300px|Dr. Lim, Hyang-Tag (KIST)]]
* Speaker: [[Lim, Hyang-Tag|Dr. Lim, Hyang-Tag (KIST)]]
* Date: Wednesday October 30, 2019 05:00pm
* Place: Jungho Seminar Rooom

===Abstract===

Realization of a strongly interacting photonic systems is one of the essential issues in quantum optics. In solid-state systems, exciton-polaritons in micro-cavities, consisting of a cavity photon and a quantum well exciton, have interactions based on short-range exchange interaction between direct excitons. These interactions have lead to manifestation of a number of intriguing collective phenomena such as formation of spontaneous coherence, observation of vortex-antivortex pairs and dark solitons, and realization of polariton Josephson effect. However, a mean field approach has been successful to describe all these observations accurately. Increasing interactions between polaritons further is crucial to explore physics beyond mean-field description and to explore a new regime of strongly correlated photons.

In this presentation, I will discuss mainly two results. First, I will report that application of perpendicular electric and magnetic fields can generate a tunable artificial gauge potential for exciton-polaritons [1]. The strength and direction of the effected gauge potential are controlled electrically. Then, I will report that interaction between (dipolar) polaritons can be substantially increased by increasing size of the dipole moment of the polaritons. In our structure, one can tune the dipole size of dipolar polaritons by tuning the applied gate voltage, which controls growth directional electric fields. We observed more than factor of 5 enhancement in the interaction strength to linewidth ratio [2]. Together with strong polariton-polariton interactions and engineered polariton lattices, we believe that an artificial gauge field could play a key role in investigation of non-equilibrium dynamics of strongly correlated photons. In addition, dipolar polaritons could be used to demonstrate a polariton blockade effect, which could be the first demonstration of true quantum nature of polaritons beyond semi-classical description.

===References===

#H.-T. Lim*, E. Togan*, M. Kroner, J. Miguel-Sanchez, and A. Imamoglu, Nature Commun. 8, 14540 (2017).
#E. Togan*, H.-T. Lim*, S. Faelt, W. Wegscheider, and A. Imamoglu, Phys. Rev. Lett. 121, 227402 (2018).

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

File:Wang Ya.JPG

2019-08-29T07:40:38Z

Namanse23:

Quantum control of hybrid spin system in diamond: towards scalable quantum network

2019-08-29T07:40:26Z

Namanse23: Created page with "Prof. Wang, Ya (University of Science and Technology of China) * Speaker: Wang, Ya|Prof. Wang, Ya (University of Science and Technology of..."

[[file:Wang_Ya.JPG|thumb|x300px|Prof. Wang, Ya (University of Science and Technology of China)]]
* Speaker: [[Wang, Ya|Prof. Wang, Ya (University of Science and Technology of China)]]
* Date: Wednesday September 11, 2019 05:00pm
* Place: Jungho Seminar Room

The realization of quantum network is an important goal in quantum information due to its great potential in secure quantum communication and promising scalability in quantum computing. Building quantum network requires quantum systems with long coherence time, efficient optical interface as well as ability to scale-up. Point defects in solids with individual controllable spin come into focus in recent years. One most promising candidate system is nitrogen vacancy in diamond. In this talk, I will present our recent progress in developing hybrid quantum node composed of NV electron spin and surrounding nuclear spins, including the ways to control them and high quality diamond sample preparation.

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

Wang, Ya

2019-08-29T07:32:30Z

Namanse23:

[[file:Wang_Ya.JPG|thumb|x300px|Prof. Wang, Ya (University of Science and Technology of China)]]

Ya Wang is a Professor of Physics in the Department of Modern Physics at the University of Science and Technology of China (USTC).

He received his Phd degree in Physics from Hefei National Laboratory for Physical Sciences at the Microscale (USTC) in 2012. Subsequently, he jointed the group of Prof. Joerg Wrachtrup at Stuttgart University as a post-doc. In 2016, he was supported by “Hundred Talents Program” of Chinese Academy of Sciences and appointed as a research fellow at the Department of Modern Physics at USTC. In 2018, he was selected in “Thousand Youth Talent Program” and became a Professor at the same department.

His recent interest focus on developing techniques to build a diamond based scalable quantum network, including diamond CVD growth and fabrication technique to get good quality Nitrogen Vacancy center in diamond, microwave and optical control technique to realize high-fidelity entangled state in hybrid electron-nuclear spin system.

[[Category:Speakers]]
[[Category:Condensed Matter Speakers]]

Wang, Ya

2019-08-29T07:26:17Z

Namanse23: Created page with "Prof. Wang, Ya (University of Science and Technology of China) Ya Wang is a Professor of Physics in the Department of Modern Physics at the..."

[[file:Wang Ya.JPG|thumb|x300px|Prof. Wang, Ya (University of Science and Technology of China)]]

Ya Wang is a Professor of Physics in the Department of Modern Physics at the University of Science and Technology of China (USTC).

He received his Phd degree in Physics from Hefei National Laboratory for Physical Sciences at the Microscale (USTC) in 2012. Subsequently, he jointed the group of Prof. Joerg Wrachtrup at Stuttgart University as a post-doc. In 2016, he was supported by “Hundred Talents Program” of Chinese Academy of Sciences and appointed as a research fellow at the Department of Modern Physics at USTC. In 2018, he was selected in “Thousand Youth Talent Program” and became a Professor at the same department.

His recent interest focus on developing techniques to build a diamond based scalable quantum network, including diamond CVD growth and fabrication technique to get good quality Nitrogen Vacancy center in diamond, microwave and optical control technique to realize high-fidelity entangled state in hybrid electron-nuclear spin system.

[[Category:Speakers]]
[[Category:Condensed Matter Speakers]]

File:Wagn Ya.JPG

2019-08-29T07:23:13Z

Namanse23:

Role of Organic Molecules in Organic-Inorganic Solar Cell Perovskites

2019-07-17T05:50:04Z

Namanse23: Created page with "Prof. Lee, Seung-Hun(University of Virginia) * Speaker: Prof. Lee, Seung-Hun(University of Virginia) * Date: Wednesday Jul..."

[[file:S-H_Lee.jpg|thumb|x300px|Prof. Lee, Seung-Hun(University of Virginia)]]
* Speaker: [[Lee, Seung-Hun|Prof. Lee, Seung-Hun(University of Virginia)]]
* Date: Wednesday July 24, 2019 11:00am
* Place: Jungho Seminar Room

===Abstract===

The record solar cell efficiency based on hybrid organic-inorganic perovskites (HOIPs) has reached 22.7% which rivals that of conventional silicon solar cells. Combined with its inexpensive solution-based processing and all earth abundant compositions, HOIPs are among the most promising next generation solar cell materials. In this talk, I will present our recent studies, using elastic and inelastic neutron scattering and photoluminescence techniques, and density functional theory calculations, on two HOIPs, methylammonium lead iodide and formamidinium lead iodide, to shed lights on the microscopic mechanism of the photovoltaic properties of the HOIPs.

===References===

# Role of Organic Molecules in Phonon Melting and Charge Screening in Hybrid Organic-Inorganic Perovskites, Depei Zhang, Maiko Kofu, Tianran Chen, Wei-Liang Chen, Alexander Z. Chen, Mina Yoon, Chinnambedu Murugesan Raghavan, Tzu-Pei Chen, Douglas L. Abernathy, Benjamin J. Foley, Craig M. Brown, Guangyong Xu, Leland W. Harriger, Ryoichi Kajimoto, Mitsutaka Nakamura, Seiko Ohira-Kawamura, Chun-Wei Chen, Yu-Ming Chang, Joshua J. Choi, and Seung-Hun Lee, submitted (2019).
# Origin of Long Lifetime of Band-Edge Charge Carriers in Organic-Inorganic Lead Iodide Perovskites, Tianran Chen, Wei-Liang Chen, Benjamin J. Foley, Jooseop Lee, Jacob Ruff, J. Y. Peter Ko, Craig M. Brown, Leland W. Harriger, Depei Zhang, Changwon Park, Mina Yoon, Yu-Ming Chang, Joshua J. Choi, and Seung-Hun Lee, Proceedings of National Academy of Sciences 114, 7519-7524 (2017).
# Entropy Driven Structural Transition and Kinetic Trapping in Formamidinium Lead Iodide Perovskite, Tianran Chen, Benjamin J. Foley, Changwon Park, Craig M. Brown, Leland W. Harriger, Jooseop Lee, Jacob Ruff, Mina Yoon, Joshua J. Choi, and Seung-Hun Lee, Science Advances 2, e1601650 (2016).
# Rotational dynamics of organic cations in CH3NH3PbI3, T. Chen, B. J. Foley, B. Ipek, M. Tyagi, J.R.D. Copley, C. M. Brown, J. J. Choi, S.-H. Lee, Phys. Chem. Chem. Phys. 17, 31278-31286 (2015).

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

File:Shen sq.jpg

2019-07-04T05:05:02Z

Namanse23:

Topological Anderson Insulator: Theory and Experiments

2019-07-04T04:32:30Z

Namanse23:

[[file:Nobody.jpg|thumb|x300px|Prof. Shen, Shun-Qing (University of Hong Kong)]]
* Speaker: [[Shen, Shun-Qing|Prof. Shen, Shun-Qing (University of Hong Kong)]]
* Date: Wednesday July 24, 2019 05:00pm
* Place: Jungho Seminar Room

Topological Anderson insulator is a novel quantum state of matter, which was predicted by Shen and his collaborators in 2009. Usually a topological insulator is robust against disorders in the band gap of electronic band structure. Strong disorders close the band gap and make all states localized to form Anderson insulator. Topological Anderson insulator is a surprising discovery that sufficient disorder can drive a trivial insulator into a topologically non-trivial insulator in which protected edge states emerge, leading quantized transport in two dimensions. Disorder, besides causing Anderson localization of bulk electronic states, is fundamentally responsible for inducing nontrivial topology order into the system, and hence creating protected edge modes in a mobility gap instead of a band gap. This work has opened a new direction in studying the nontrivial interplay between disorder and topological order. Since then the discovery has since triggered relevant works in a variety of systems such as topological insulators of different dimensions (PRL 2010), topological superconductors (PRB 2016) and photonic crystals (PRL 2013). Very recently, the discovery was confirmed experimentally by Szameit and Segev groups from Germany and Israel in photonic crystals (Nature 560, 461 (2018)) and Gadway and Massignnan groups from USA and Spain in cold atoms (Science 262, 929(2018)), respectively. The experimental demonstration of the topological Anderson insulator shows that disorder can enhance robust topological transport rather than arrest it. Besides, the photonic crystal and cold atoms are two completely different platforms. Observation of topological Anderson insulator in these two systems show that the phenomenon is quite general, emerging across a large range of disordered systems.

References:
1. Topological Anderson insulator, J. Li, R. L. Chu, J. K. Jain & S. Q. Shen, Physical Review Letters 102, 136806 (2009)
2. Photonic topological Anderson insulators, S. Stutzer et al., Nature 560, 461 (2018)
3. Observation of the topological Anderson insulator in disordered atomic wires, E. J. Meier et al., Science 262, 929 (2018)

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

Topological Anderson Insulator: Theory and Experiments

2019-07-04T04:31:30Z

Namanse23:

[[file:Nobody.jpg|thumb|x300px|Prof. Shen, Shun-Qing (University of Hong Kong)]]
* Speaker: [[Shen, Shun-Qing|Prof. Shen, Shun-Qing (University of Hong Kong)]]
* Date: Wednesday July 24, 2019 05:00pm
* Place: Jungho Seminar Room

Topological Anderson insulator is a novel quantum state of matter, which was predicted by Shen and his collaborators in 2009. Usually a topological insulator is robust against disorders in the band gap of electronic band structure. Strong disorders close the band gap and make all states localized to form Anderson insulator. Topological Anderson insulator is a surprising discovery that sufficient disorder can drive a trivial insulator into a topologically non-trivial insulator in which protected edge states emerge, leading quantized transport in two dimensions. Disorder, besides causing Anderson localization of bulk electronic states, is fundamentally responsible for inducing nontrivial topology order into the system, and hence creating protected edge modes in a mobility gap instead of a band gap. This work has opened a new direction in studying the nontrivial interplay between disorder and topological order. Since then the discovery has since triggered relevant works in a variety of systems such as topological insulators of different dimensions (PRL 2010), topological superconductors (PRB 2016) and photonic crystals (PRL 2013). Very recently, the discovery was confirmed experimentally by Szameit and Segev groups from Germany and Israel in photonic crystals (Nature 560, 461 (2018)) and Gadway and Massignnan groups from USA and Spain in cold atoms (Science 262, 929(2018)), respectively. The experimental demonstration of the topological Anderson insulator shows that disorder can enhance robust topological transport rather than arrest it. Besides, the photonic crystal and cold atoms are two completely different platforms. Observation of topological Anderson insulator in these two systems show that the phenomenon is quite general, emerging across a large range of disordered systems.
References:
1. Topological Anderson insulator, J. Li, R. L. Chu, J. K. Jain & S. Q. Shen, Physical Review Letters 102, 136806 (2009)
2. Photonic topological Anderson insulators, S. Stutzer et al., Nature 560, 461 (2018)
3. Observation of the topological Anderson insulator in disordered atomic wires, E. J. Meier et al., Science 262, 929 (2018)

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

Topological Anderson Insulator: Theory and Experiments

2019-07-04T04:29:28Z

Namanse23:

Topological Anderson Insulator: Theory and Experiments

2019-07-04T04:22:28Z

Namanse23: Created page with "Prof. Shen, Shun-Qing (University of Hong Kong) * Speaker: Prof. Shen, Shun-Qing (University of Hong Kong) * Date: Wednesd..."

Ovartchaiyapong, Preeti

2019-07-01T08:23:13Z

Namanse23: Created page with "Dr. Ovartchaiyapong, Preeti (Thammasat University) Reseach Fellow at Thammasat University ==Educations== * Ph.D. Solid Stat..."

[[file: Ovartchaiyapong Preeti.jpg|thumb|x300px|Dr. Ovartchaiyapong, Preeti (Thammasat University)]]
Reseach Fellow at Thammasat University

==Educations==
* Ph.D. Solid State Physics, University of California, Santa Barbara, USA, 2016
* M.A. Solid State Physics, University of California, Santa Barbara, USA, 2013
* B.S. Engineering Physics, University of Illinois at Urbana-Champaign, USA, 2010

==Professional Experiences==
* Graduate Student Researcher, University of California Santa Barbara, 2010-2016
* Undergraduate Research Assistant, University of Illinois at Urbana-Champaign, 2007-2010
* Research Intern, Technische Universitat Darmstadt, Hessen, Germany, Summer 2008

==Contributions==
* [[Strain-coupled hybrid devices based on single-crystal diamond mechanical resonators and nitrogen-vacancy center qubits]]

[[Category:Speakers]]
[[Category:Condensed Matter Speakers]]

File:Ovartchaiyapong Preeti.jpg

2019-07-01T06:11:18Z

Namanse23:

Strain-coupled hybrid devices based on single-crystal diamond mechanical resonators and nitrogen-vacancy center qubits

2019-07-01T06:10:53Z

Namanse23: Created page with "Dr. Ovartchaiyapong, Preeti (Thammasat University) * Speaker: Ovartchaiyapong, Preeti|Dr. Ovartchaiyapong, Preeti (Thammasa..."

[[file: Ovartchaiyapong Preeti.jpg|thumb|x300px|Dr. Ovartchaiyapong, Preeti (Thammasat University)]]
* Speaker: [[Ovartchaiyapong, Preeti|Dr. Ovartchaiyapong, Preeti (Thammasat University)]]
* Date: Wednesday July 10, 2019 05:00pm
* Place: Jungho Seminar Room

Hybrid quantum systems have recently attracted growing interest from researchers in various fields, with the prospect of combining the advantages different quantum systems while compensating for their individual weaknesses. In this talk, we explore a monolithic hybrid system based on single-crystal diamond (SCD) mechanical resonators and the embedded nitrogen-vacancy (NV) centers qubits. Despite the promising prospects of such a monolithic NV center- mechanical resonator system, challenges in single-crystal diamond fabrication while maintaining the coherent quantum properties of the NV center have limited its realization. Furthermore, the strain sensitivities of the NV center have also not been well studied due to the lack of a high-quality diamond mechanical platform.

To address these previous limitations, this talk will discuss techniques for fabricating high-quality SCD mechanical resonators and further, the utilization of these resonators to both study NV center strain coupling and exert control over the NVs spin and orbital states. SCD mechanical resonators were fabricated using a diamond-on-insulator (DOI) platform. Using the controlled strain field generated by the resonator’s deflections, the strain sensitivities of both the NV’s ground state spin and excited state transitions were studied on the individual NV basis. We demonstrated dynamic coupling of the AC strain to the resonator spins, as well as coherent modulations of the NV center’s optical transitions. Utilizing our advancements in diamond fabrication and the resulting improved understanding of the strain sensitivity in NV centers, we discuss the future developments needed to reach the quantum regime of coupling.

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

Precision metrology with Bose-Einstein Condensates

2019-05-13T05:01:19Z

Namanse23: Created page with "Dr. Lee, Jae Hoon (KRISS) * Speaker: Dr. Lee, Jae Hoon (KRISS) * Date: Wednesday May 22, 2019 05:00pm * Place: Jungho..."

[[file:Jae Hoon Lee.jpg|thumb|x300px|Dr. Lee, Jae Hoon (KRISS)]]
* Speaker: [[Lee, Jae Hoon|Dr. Lee, Jae Hoon (KRISS)]]
* Date: Wednesday May 22, 2019 05:00pm
* Place: Jungho Seminar Room

Atomic systems, having the advantage of possessing universal properties, are widely used in
quantum sensors requiring absolute accuracy, such as atomic clocks. In particular, leveraging matter
wave interference in Bose-Einstein condensates (BECs) allow for “macroscopic” observation of
quantum effects that are typically attributed to the physical phenomena of single atoms. Atomic
physics experiments at KRISS are introduced which are geared towards precision metrology by
utilizing the amplification of quantum signatures with BECs. Furthermore, we explore ways to
generate, control, and measure quantum states in atomic and nanomechanical systems which can
lead to enhanced quantum sensing.

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

File:Jae Hoon Lee.jpg

2019-05-13T04:57:53Z

Namanse23:

Lee, Jae Hoon

2019-05-13T04:54:33Z

Namanse23: Created page with "Dr. Lee, Jae Hoon (KRISS) Reseach Fellow at KRISS ==Education== * Ph.D. Optical Sciences, University of Arizona, 2012 * MS. Optical Sc..."

[[file:Jae Hoon Lee.jpg|thumb|x300px|Dr. Lee, Jae Hoon (KRISS)]]

Reseach Fellow at KRISS

==Education==
* Ph.D. Optical Sciences, University of Arizona, 2012
* MS. Optical Sciences, University of Arizona, 2007
* MS. Physics, Yonsei University, 2005
* BS. Physics, Yonsei University, 2003

==professional Experiences==
* Senior Research Scientist, Korea Research Institute of Standards and Science, 2014 - present
* Postdoctoral Fellow, California Institute of Technology, 2012 - 2014
* Research Associate, University of Arizona, 2005 - 2012
* Research Assistant, Yonsei University, 2003 - 2005

==Contributions==
* [[Precision metrology with Bose-Einstein Condensates]]

[[Category:Speakers]]
[[Category:Condensed Matter Speakers]]

Search for magnetic version of Dirac particles and their topological excitations

2019-03-22T05:20:30Z

Namanse23: Created page with "Prof. Chung, Jae-Ho (Korea University) * Speaker: Prof. Chung, Jae-Ho (Korea University) * Date: Wednesday April 03,..."

[[file: Jae-Ho_Chung.jpg|thumb|x300px|Prof. Chung, Jae-Ho (Korea University)]]
* Speaker: [[Chung, Jae-Ho|Prof. Chung, Jae-Ho (Korea University)]]
* Date: Wednesday April 03, 2019 05:00pm
* Place: Jungho Seminar Room

In Dirac materials, electrons move as photon-like particles with constant velocities independently of linear momentum. If local magnetic fluxes induce insulating gaps on bulk bands, these particles may flow only along their topological edges or surfaces allowing dissipation-less transport. While such fermionic topological Dirac materials are already well known, their bosonic counterparts have only recently been brought into attention. In this talk, we will review the early and recent inelastic neutron scattering works on magnon Dirac materials, and thereby discuss the ongoing search for the magnonic topological Dirac modes.

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

File:Jae-Ho Chung.jpg

2019-03-19T02:31:20Z

Namanse23:

Chung, Jae-Ho

2019-03-19T02:30:46Z

Namanse23: Created page with "Prof. Jae-Ho Chung (Korea Univ) Professor in Department of Physics at korea Univ. '''Professor Of Physics''' Jae-Ho Chung is a conde..."

[[file:Jae-Ho Chung.jpg|thumb|x300px|Prof. Jae-Ho Chung (Korea Univ)]]

Professor in Department of Physics at korea Univ.

'''Professor Of Physics'''

Jae-Ho Chung is a condensed matter physicist specializing in magnetic materials. He received is B.S. degree (1992) from Seoul National University and Ph.D. (2003) from the University of Pennsylvania. Before coming to Korea University He was a postdoc at the University of Maryland and the NIST Center for Neutron Research.

==Research Interests==
Spin order and disorder in geometrically frustrated antiferromagnets, competition between lattice and spin degrees of freedom, magnetic order and dynamics of magneto-electric multiferroics, lattice dynamics and electron-lattice interactions, exchange couplings in magnetic semiconductors.

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

ON QUANTUM DIALOGUE

2019-03-18T01:12:03Z

Namanse23: Created page with "Prof. Nguyen Ba An (Thang Long University, Vietnam) * Speaker: Prof. Nguyen Ba An (Thang Long University, Vietnam) * Date: W..."

[[file:Prof_An.png|thumb|x300px|Prof. Nguyen Ba An (Thang Long University, Vietnam)]]
* Speaker: [[Nguyen Ba An|Prof. Nguyen Ba An (Thang Long University, Vietnam)]]
* Date: Wednesday March 27, 2019 05:00pm
* Place: Jungho Seminar Room

Secure communication is a legitimate demand of the mankind. In order for one party (Alice) to send a confidential message to another party (Bob), the two have to share beforehand a secret key which must be used only once to encode/decode the message. Such a “one-time” private-key system for communication is absolutely secure but inconvenient in practice. Of current use is the public-key system which is very convenient practically, but its (unproven) security will be broken if quantum computers come into birth. To guarantee unconditional security even in the presence of quantum computers, quantum key distribution (QKD) needs to be deployed prior to an actual communication. That is, resorting to the laws of Nature, Alice and Bob are able to remotely establish secret keys under the nose of any eavesdroppers. However, what should be done in emergent circumstances when Alice and Bob wish to directly exchange their information but do not have enough time to implement a QKD protocol? In other words, can they still securely "talk" with each other without a prior key distribution? We show that this turns out to be possible by means of the so-called "quantum dialogue", which rationally exploits the quantum entanglement resources, quantum operations and quantum measurements [1,2]. Somewhat more surprisingly, even quantum nonselective measurements (i.e., measurements without reading the outcome) make sense to the quantum dialogue [3], an unbelievably counterintuitive fact in our everyday life!

[1] N. B. An, Phys. Lett. A 328, 6 (2004): Quantum dialogue
[2] N. B. An, J. Kor. Phys. Soc. 47, 562 (2005): Secure dialogue without a prior key distribution
[3] N. B. An, Adv. Nat. Sci.: Nanosci. Nanotech. 9, 025001 (2018): Quantum dialogue by nonselective measurements

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

Harnessing Mesoscopic Mechanical Systems for New Quantum Technologies

2019-03-04T01:40:11Z

Namanse23: Created page with "Prof. Hong, Sungkun (KAIST) * Speaker: Prof. Hong, Sungkun (KAIST) * Date: Wednesday May 15, 2019 05:00pm * Place: Jungho Se..."

[[file:Nobody.jpg|thumb|x300px|Prof. Hong, Sungkun (KAIST)]]
* Speaker: [[Hong, Sungkun|Prof. Hong, Sungkun (KAIST)]]
* Date: Wednesday May 15, 2019 05:00pm
* Place: Jungho Seminar Room

Quantum optomechanics is an emerging field in quantum science that aims to control quantum motions of mechanical objects using light-matter interactions. In recent years, the researchers started gaining quantum control over several mesoscopic mechanical systems. This advancement opens exciting possibilities for developing new quantum technologies and for testing quantum physics beyond the microscopic world. In this talk, I will describe two of my works on experimental quantum optomechanics.

I will present our progress in utilizing on-chip optomechanical devices as a new resource for quantum information processing. By combining pulsed optical controls and single photon detection, we created quantum states of a silicon micromechanical resonator at a single phonon level. Based on this method, we generated the remote entanglement between two mechanical modes, paving the way for mechanics-based optical quantum memories and networks.

I will also introduce a new optomechanical system that consists of an optically levitated nanoparticle and microfabricated photonic crystal cavities. This hybrid system will exhibit an exceptional combination of mechanical quality, flexibility, and controllability, allowing for a new level of quantum control over the particle’s motion. I will discuss the current status of the experiment and plans on further developing the system for novel quantum sensing applications.

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

Huh, Joonsuk

2019-02-28T02:37:23Z

Namanse23: Created page with "Prof. Huh, Joonsuk (Sungkyunkwan Univ.) Professor at Sungkyunkwan Univ. ==Education== *Ph.D. physics, Goethe University Frankfurt, 2011..."

[[file:Huh, Joonsuk.jpg|thumb|x300px|Prof. Huh, Joonsuk (Sungkyunkwan Univ.)]]
Professor at Sungkyunkwan Univ.

==Education==
*Ph.D. physics, Goethe University Frankfurt, 2011
*M.S. computational science and engineering, TUM, 2006
*B.S. chemistry, minor in physics, Postech, 2003

==Professional Experiences==
*Assistant Professor, Department of chemistry, Sungkyunkwan University, Mar 2017 - present
*Mueunjae postdoctoral fellow, Postech, Jun 2015 - Feb 2017
*Postdoctoral researcher, Harvard University, Dec 2011 - Feb 2015
*Postdoctoral fellow, FIAS. March 2011 - Nov 2011

==Contributions==
* [[Quantum Simulation Methods for Molecular Vibronic Spectra]]

[[Category:Speakers]]
[[Category:Condensed Matter Speakers]]

Hong, Sungkun

2019-02-28T01:45:40Z

Namanse23: /* Professional Experiences */

[[file:Hong, Sungkun.jpg|thumb|x300px|Prof. Hong, Sungkun (KAIST)]]
Professor at KAIST

==Education==
* Ph.D. Applied Physics, Harvard University, 2013
* B.S. Mechanical and Aerospace Engineering, Seoul National University, 2003

==Professional Experiences==
* Associate Professor, KAIST, March 2109 - Present
*Postdoctoral Researcher, University of Vienna, Jan 2013 - Feb 2019

==Contributions==
* [[Quantum meets Mechanics: Mechanical Systems as New Resources for Quantum Technologies]]

[[Category:Speakers]]
[[Category:Condensed Matter Speakers]]

Hong, Sungkun

2019-02-28T01:40:12Z

Namanse23: Created page with "Prof. Hong, Sungkun (KAIST) Professor at KAIST ==Education== * Ph.D. Applied Physics, Harvard University, 2013 * B.S. Mechanical and A..."

[[file:Hong, Sungkun.jpg|thumb|x300px|Prof. Hong, Sungkun (KAIST)]]
Professor at KAIST

==Education==
* Ph.D. Applied Physics, Harvard University, 2013
* B.S. Mechanical and Aerospace Engineering, Seoul National University, 2003

==Professional Experiences==
* Associate Professor, KAIST, March 2109 - Present
*

==Contributions==
* [[Quantum meets Mechanics: Mechanical Systems as New Resources for Quantum Technologies]]

[[Category:Speakers]]
[[Category:Condensed Matter Speakers]]

Quantum meets Mechanics: Mechanical Systems as New Resources for Quantum Technologies

2019-02-28T01:34:24Z

Namanse23:

[[file:Hong, Sungkun.jpg|thumb|x300px|Prof. Hong, Sungkun (KAIST)]]
* Speaker: [[Hong, Sungkun|Prof. Hong, Sungkun (KAIST)]]
* Date: Wednesday May 15, 2019 05:00pm
* Place: Jungho Seminar Room

Studying quantum behaviors of mesoscopic mechanical systems is an emerging field in quantum science. The main experimental approach is optomechanics, where photons (or electromagnetic radiations) are used to measure and manipulate the motional states of mechanical structures like micromechanical oscillators. Optomechanics, together with advancements in micro- and nanofabrication, has allowed us to observe and control mechanical resonators at a quantum level. This opens new exciting possibilities for quantum science and technology as well as for studying quantum physics in hitherto untested macroscopic scales. In this talk, I will describe two of my major researches on experimental quantum optomechanics.
I will first report on our progress in utilizing on-chip optomechanical devices as a new resource for quantum information. Combining pulsed optical controls and single photon detection, we demonstrated a method that creates quantum states of a silicon micromechanical resonator at a single phonon level. Using this scheme, we generated the remote entanglement between two mechanical modes, paving the way for mechanics-based optical quantum memory and network.
Next, I will introduce a novel, hybrid optomechanical system consisting of optically levitated nanoparticles and micro-fabricated photonic crystal cavity. The system combines excellent mechanical quality and flexibility stemming from optical levitation and an efficient optical interface based on nanophotonic cavities. It thus opens completely new possibilities for mechanics-based quantum sensing and genuine quantum experiments on the macroscopic motion of the particle. I will discuss the current status of the experiment and future plans of the work that include the development of novel quantum sensors and the matter-wave interferometry in new mass scales.

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

Quantum meets Mechanics: Mechanical Systems as New Resources for Quantum Technologies

2019-02-28T01:28:45Z

Namanse23: Created page with "Prof. Hong, Sungkun (KAIST) * Speaker: Prof. Hong, Sungkun (KAIST) * Date: Wednesday May 15, 2019 05:00pm * Place: Jungho Se..."

[[file:Nobody.jpg|thumb|x300px|Prof. Hong, Sungkun (KAIST)]]
* Speaker: [[Hong, Sungkun|Prof. Hong, Sungkun (KAIST)]]
* Date: Wednesday May 15, 2019 05:00pm
* Place: Jungho Seminar Room

Studying quantum behaviors of mesoscopic mechanical systems is an emerging field in quantum science. The main experimental approach is optomechanics, where photons (or electromagnetic radiations) are used to measure and manipulate the motional states of mechanical structures like micromechanical oscillators. Optomechanics, together with advancements in micro- and nanofabrication, has allowed us to observe and control mechanical resonators at a quantum level. This opens new exciting possibilities for quantum science and technology as well as for studying quantum physics in hitherto untested macroscopic scales. In this talk, I will describe two of my major researches on experimental quantum optomechanics.
I will first report on our progress in utilizing on-chip optomechanical devices as a new resource for quantum information. Combining pulsed optical controls and single photon detection, we demonstrated a method that creates quantum states of a silicon micromechanical resonator at a single phonon level. Using this scheme, we generated the remote entanglement between two mechanical modes, paving the way for mechanics-based optical quantum memory and network.
Next, I will introduce a novel, hybrid optomechanical system consisting of optically levitated nanoparticles and micro-fabricated photonic crystal cavity. The system combines excellent mechanical quality and flexibility stemming from optical levitation and an efficient optical interface based on nanophotonic cavities. It thus opens completely new possibilities for mechanics-based quantum sensing and genuine quantum experiments on the macroscopic motion of the particle. I will discuss the current status of the experiment and future plans of the work that include the development of novel quantum sensors and the matter-wave interferometry in new mass scales.

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

Quantum Simulation Methods for Molecular Vibronic Spectra

2019-01-25T02:17:47Z

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[[file:Nobody.jpg|thumb|x300px|Prof. Huh, Joonsuk (Sungkyunkwan Univ.)]]
* Speaker: [[Huh, Joonsuk|Prof. Huh, Joonsuk (Sungkyunkwan Univ.)]]
* Date: Wednesday April 17, 2019 05:00pm
* Place: Jungho Seminar Room

Quantum computer is expected to attempt the quantum supremacy in near-term with potentially useful applications. Among the various quantum simulation problems, a quantum sampling problem with noninteracting bosonic particles, i.e. boson sampling, is very likely to demonstrate the quantum supremacy with relatively limited physical resources. In my talk, I will present a molecular problem (molecular vibronic spectra), which can be interpreted as a Gaussian boson sampling problem. Additionally, a quantum circuit based algorithm for the same molecular problem will be presented.
[[Category:Seminars]]
[[Category:Condensed Matter Seminars]]