BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CMSA - ECPv6.17.1//NONSGML v1.0//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-WR-CALNAME:CMSA
X-ORIGINAL-URL:https://cmsa.fas.harvard.edu
X-WR-CALDESC:Events for CMSA
REFRESH-INTERVAL;VALUE=DURATION:PT1H
X-Robots-Tag:noindex
X-PUBLISHED-TTL:PT1H
BEGIN:VTIMEZONE
TZID:America/New_York
BEGIN:DAYLIGHT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
DTSTART:20220313T070000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
DTSTART:20221106T060000
END:STANDARD
BEGIN:DAYLIGHT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
DTSTART:20230312T070000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
DTSTART:20231105T060000
END:STANDARD
BEGIN:DAYLIGHT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
DTSTART:20240310T070000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
DTSTART:20241103T060000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20231101T103000
DTEND;TZID=America/New_York:20231101T113000
DTSTAMP:20240222T111747Z
CREATED:20240222T111415Z
LAST-MODIFIED:20240222T111747Z
UID:10002806-1698834600-1698838200@cmsa.fas.harvard.edu
SUMMARY:Unveiling Correlated Topological Insulators through Fermionic Tensor Network States
DESCRIPTION:Topological Quantum Matter Seminar \nSpeaker: Shenghan Jiang\, Kavli Institute for Theoretical Sciences UCAS \nTitle: Unveiling Correlated Topological Insulators through Fermionic Tensor Network States \nAbstract: The study of topological band insulators has revealed fascinating phases characterized by band topology indices\, harboring extraordinary boundary modes protected by anomalous symmetry actions. In strongly correlated systems\, it has been established that topological insulator phases persist as stable phases. However\, due to the inability to express the ground states of such systems as Slater determinants\, the formulation of generic variational wavefunctions for numerical simulations is highly desirable.\nIn this talk\, we tackle this challenge by developing a comprehensive framework with fermionic tensor network states. Starting from simple assumptions\, we write down tensor equations\, construct edge theories and extract quantum anomaly data for topological insulators. By exhaustively exploring all possible sets of equations\, we achieve a systematic classification of topological insulator phases. Imposing the solutions of a given set of equations onto local tensors\, we obtain generic variational wavefunctions for corresponding topological insulator phases. Our methodology provides a crucial first step towards simulating topological insulators in strongly correlated systems. \n 
URL:https://cmsa.fas.harvard.edu/event/tqms_11123/
LOCATION:Virtual
CATEGORIES:Topological Quantum Matter Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Topological-Seminar-11.01.23.docx-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20231102T163000
DTEND;TZID=America/New_York:20231102T180000
DTSTAMP:20240222T112133Z
CREATED:20240222T112133Z
LAST-MODIFIED:20240222T112133Z
UID:10002808-1698942600-1698948000@cmsa.fas.harvard.edu
SUMMARY:Landscape of quantum phases in quantum materials
DESCRIPTION:Joint Quantum Matter in Mathematics and Physics and Topological Quantum Matter Seminar \nSpeaker: Liujun Zou (Perimeter Institute) \nTitle: Landscape of quantum phases in quantum materials\n\nAbstract: A central goal of condensed matter physics is to understand which quantum phases of matter can emerge in a quantum material. For this purpose\, one should be able to not only describe the quantum phases using some effective field theories\, but also capture the important microscopic information of the material via mathematical formulation. In this talk\, I will present a framework to classify quantum phases in quantum materials\, where the microscopic information of a material is encoded in its quantum anomaly. I will talk about the application of this framework to classify various exotic quantum phases of matter in different lattice systems. Using our framework\, we have obtained many results unexpected from the previous literature.
URL:https://cmsa.fas.harvard.edu/event/tqms_102523/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Quantum Matter,Topological Quantum Matter Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Special-Joint-QMMP-Topological-QM-11.02.23.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20231109T163000
DTEND;TZID=America/New_York:20231109T173000
DTSTAMP:20240222T110327Z
CREATED:20240222T110254Z
LAST-MODIFIED:20240222T110327Z
UID:10002805-1699547400-1699551000@cmsa.fas.harvard.edu
SUMMARY:Uniqueness of Landau levels and their analogs with higher Chern numbers
DESCRIPTION:Topological Quantum Matter Seminar \nSpeaker: Bruno Mera\, Instituto Superior Tecnico \nTitle: Uniqueness of Landau levels and their analogs with higher Chern numbers \nAbstract: Lowest Landau level wavefunctions are eigenstates of the Hamiltonian of a charged par- ticle in two dimensions under a uniform magnetic field. They are known to be holomorphic both in real and momentum spaces\, and also exhibit uniform\, translationally invariant\, geometrical properties in momentum space. In this talk\, using the Stone-von Neumann the- orem\, we show that lowest Landau level wavefunctions are indeed the only possible states with unit Chern number satisfying these conditions. We also prove the uniqueness of their direct analogs with higher Chern numbers and provide their expressions. \nRef: Bruno Mera and Tomoki Ozawa. Uniqueness of Landau levels and their analogs with higher Chern numbers. arXiv:2304.00866\, 2023. arXiv:2304.00866. \n 
URL:https://cmsa.fas.harvard.edu/event/tqms_11823/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Topological Quantum Matter Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Topological-Seminar-11.09.23.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20231115T103000
DTEND;TZID=America/New_York:20231115T113000
DTSTAMP:20240222T105913Z
CREATED:20240222T105852Z
LAST-MODIFIED:20240222T105913Z
UID:10002803-1700044200-1700047800@cmsa.fas.harvard.edu
SUMMARY:A bulk gap in the presence of edge states for a truncated Haldane pseudopotential
DESCRIPTION:Topological Quantum Matter Seminar \nSpeaker: Amanda Young\, UIUC \nTitle: A bulk gap in the presence of edge states for a truncated Haldane pseudopotential \nAbstract: Haldane pseudopotentials were first introduced as Hamiltonian models for the fractional quantum Hall effect\, and it has been long expected that they should exhibit the characteristic properties of this exotic phase of matter\, including a spectral gap above the ground state energy. We will discuss recent work that verified this gap conjecture for a truncated version of the 1/3-filled Haldane pseudopotential in the cylinder geometry. Numerical evidence suggested that for open boundary conditions the gap of the truncated model closes as the cylinder radius converges to zero and that this closure is due to the presence of edge modes; in contrast\, for periodic boundary conditions\, the gap remains robustly order one in the same radius limit. The standard scheme for applying spectral gap estimating techniques to the model with periodic boundary conditions\, though\, produces a lower bound on the bulk gap that still reflects the energy of the edge modes. To obtain an estimate on the bulk gap that reflects its true behavior\, a new gap estimating strategy was developed. By customizing the spectral gap method to key invariant subspaces of the Hamiltonian\, we are able to successfully avoid the edge states and produce a more accurate lower bound on the bulk gap. In this talk\, we discuss this invariant subspace strategy for proving bulk gaps in the presence of edge states. This is based off joint work with S. Warzel. \n  \n 
URL:https://cmsa.fas.harvard.edu/event/tqms_111523/
LOCATION:Virtual
CATEGORIES:Topological Quantum Matter Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Topological-Seminar-11.15.23.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20231120T140000
DTEND;TZID=America/New_York:20231120T150000
DTSTAMP:20240222T105558Z
CREATED:20240222T103744Z
LAST-MODIFIED:20240222T105558Z
UID:10002800-1700488800-1700492400@cmsa.fas.harvard.edu
SUMMARY:Emergent composite-fermion Luttinger liquid at the half-filled Landau level
DESCRIPTION:Topological Quantum Matter Seminar \nSpeaker: Prashant Kumar\, University of Chicago \nTitle: Emergent composite-fermion Luttinger liquid at the half-filled Landau level \nAbstract: The half-filled Landau level is a fascinating point in the phase diagram of quantum Hall effect that has been hypothesized to be a non-Fermi liquid where composite-fermions (CFs) emerge at low energies. In this talk\, I will present our numerical calculations of the excitation spectrum of this state on infinite cylinders. By comparing our results with a quasi-1D theory of CFs\, we show compelling quantitative evidence for the emergence of a Luttinger liquid of composite-fermions at low energies\, distinct from that of electrons. I will comment on some future directions.
URL:https://cmsa.fas.harvard.edu/event/tqms_112023/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Topological Quantum Matter Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Topological-Seminar-11.20.23-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20231129T170000
DTEND;TZID=America/New_York:20231129T180000
DTSTAMP:20240221T100813Z
CREATED:20240221T100735Z
LAST-MODIFIED:20240221T100813Z
UID:10002773-1701277200-1701280800@cmsa.fas.harvard.edu
SUMMARY:Anomalous Landau level analog in solids: search and implications for 2d heterostructures
DESCRIPTION:Topological Quantum Matter Seminar \nSpeaker: Valentin Crepel\, Flatiron Institute \nTitle: Anomalous Landau level analog in solids: search and implications for 2d heterostructures \nAbstract: The recent experimental observation of fractional Chen insulators — the analog of fractional quantum Hall states realized in absence of any applied magnetic field — calls for more detailed theoretical investigations of the special conditions allowing their emergence. To gain some insight on this problem\, we can rely on (i) our extensive knowledge of the physical properties of Landau levels\, and (ii) the identification of their exact solid state analogs. \nIn this talk\, (i-ii) will be discussed in the case of ”anomalous Landau levels”\, which are protected by an index theorem\, and whose most famous representative are the zero-th Landau levels of graphene. In particular\, I will derive the generic form of Bloch wave functions realizing the analog of such anomalous Landau levels\, and argue that twisted transition metal dichalcogenides homobilayers (in which fractional Chern insulators were first discovered) almost realize such anomalous bands.
URL:https://cmsa.fas.harvard.edu/event/tqms_112923/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Topological Quantum Matter Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Topological-Seminar-11.29.23.docx-1_Page_1.png
END:VEVENT
END:VCALENDAR