logo

korean english

게시판

Home > 게시판 > 세미나

다음과 같이 세미나 모임을 개최합니다. 많은 참석 부탁합니다. 


날짜: 2015/ 5/16 () 발표는 10:30부터 시작합니다.

장소: 삼성 학술 정보관 7 Creative Learning Room


연사: 정석범 교수 (서울대)

제목: Searching for Majorana fermions

초록:

At the dawn of modern physics, there were two different attempts to reconcile quantum mechanics with special relativity for electrons.  When it was recognized that the earlier attempt by Dirac required  the existence of the anti-particle, a colleague of Fermi, Ettore Majorana, came up with a solution that does not require anti-particles. While this concept for a long time had been considered merely as a possible theory for neutrinos, there recently has been active interest in possibility of  Majorana fermions in condensed matter system as an instance of electron fractionalization. The host system for such Majorana fermions are the superconducting analogues of the topological insulators, known as topological superconductors. I will discuss both the conceptual issues and the experimental progresses of this topological superconductor both in 1D and in higher-D.


연사: 조길영 박사 (과학원)

제목: Geometry of Fractional Quantum Hall states

초록:

Fractional quantum Hall (FQH) fluids of two-dimensional electron gases (2DEG) in large magnetic fields are fascinating topological states of matter. As such they are characterized by universal properties such as their fractional quantum Hall conductivity, fractionally charged anyonic excitations and a degeneracy of topological origin on surfaces with the topology of a torus. Quite surprisingly these topological fluids also couple to the geometry on which the 2DEG resides and have universal responses to adiabatic changes in the geometry. These responses are given by a Wen-Zee term (which describes the coupling of the currents to the spin connection of the geometry) and a gravitational Chern-Simons term which reflects the universal energy and momentum transport along the edges of the FQH state. We use a field theory of the FQH  states to derive these universal responses [1, 2]. To account for the coupling to the background geometry, we show that the concept of flux attachment needs to be modified and use it to derive the geometric responses from Chern-Simons theories. We show that the resulting composite particles minimally couple to the spin connection of the geometry [1]. Taking account of the framing anomaly of the quantum Chern-Simons theories [2], we derive a consistent theory of geometric responses from the Chern-Simons effective field theories and from parton constructions, and apply it to both abelian and non-abelian states. If time allows, we will also discuss the implications [3-4] of the geometric responses on the so-called nematic fractional quantum Hall states which is recently found in experiments.

[1] GYC, You, and Fradkin, PRB, 90, 115139 (2014)

[2] Gromov, GYC, You, Abanov, and Fradkin, PRL, 114, 016805 (2014)

[3] GYC, Parrikar, You, Reigh, and Hughes, PRB, 91, 035122 (2014)

[4] You, GYC, and Fradkin, PRX, 4, 041050, (2015)   


번호 제목 날짜 조회 수
공지 2021학년도 1학기 콜로퀴움 일정 2021.01.13 13671
공지 <12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생 2016.11.28 608564
435 <Sep. 30(Wed.) 4:30 PM>Local electronic structures of stacking grain boundary in bilayer graphene 2015.09.23 50930
434 <Sep. 23(Wed.) 4:30 PM>Grain boundary effect in Metal : A journey of discovery from crystal to thin films without grain boundaries 2015.09.16 45395
433 <Sep. 18(Fri.) 4:00 PM> Special seminar 2015.09.16 41258
432 <Sep. 16(Wed.) 4:30 PM> Watching molecular targets in living bodies: the cutting edge in clinical medicine 2015.09.09 45972
431 <Sep. 9(Wed.) 4:30 PM> Electronic structures of strongly-correlated systems 2015.09.03 47922
430 <8/29(토)> 세미나 개최 안내 2015.09.01 42613
429 2015학년도 2학기 콜로퀴움 일정 2015.08.06 70625
428 <6/9(화)> 세미나 개최 안내 2015.06.09 41714
427 <6/10(수) 오후4:30분> Closing in on the Axion Dark Matter hypothesis 2015.06.03 43980
426 <6/2(화)> 세미나 개최 안내 2015.06.01 42538
425 <6/3(수) 오후4:30분> The Quest for Dark Matter: Discovering Its Nature Underground? 2015.05.28 43128
424 <5/26(화)> 세미나 개최 안내 2015.05.27 41409
423 <5/27(수) 오후4:30분>Controlling phases in epitaxial transition metal oxide thin films 2015.05.21 53072
» <5/16(토)> 세미나 개최 안내 2015.05.18 121194
421 <5/20(수) 오후4:30분> Nonequilibrium statistical physics for Brownian heat engine 2015.05.14 48858
420 <5/13(수) 오후4:30분> 내가 몰랐던 대한민국 2015.05.07 43582
419 <5/6(수) 오후4:30분> 빛의 여행 2015.04.29 44405
418 <4/25(토)> 세미나 개최 안내 2015.04.23 44321
417 <4/29(수) 오후4:30분> 양자정보 2015.04.23 44847
416 <4/24(금)> 초청세미나 개최 안내 file 2015.04.13 43825