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:20231004T103000 DTEND;TZID=America/New_York:20231004T113000 DTSTAMP:20240221T111849Z CREATED:20240221T111722Z LAST-MODIFIED:20240221T111849Z UID:10002779-1696415400-1696419000@cmsa.fas.harvard.edu SUMMARY:Dipolar and modulated symmetry protected topological phases DESCRIPTION:Topological Quantum Matter Seminar \nSpeaker: Ho Tat Lam\, MIT \nTitle: Dipolar and modulated symmetry protected topological phases \nAbstract: Modulated symmetries are symmetries whose symmetry generators exhibit spatial modulations. We will discuss one-dimensional symmetry protected topological (SPT) phases protected by modulated symmetries. We will present a simple recipe for constructing modulated SPT models by generalizing the concept of decorated domain walls. We will then focus on the simplest modulated SPT protected by dipolar symmetries\, classify them using matrix product states and construct their response field theories using twisted finite tensor gauge theories. URL:https://cmsa.fas.harvard.edu/event/tqms_10423/ 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-10.04.23.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20231016T140000 DTEND;TZID=America/New_York:20231016T150000 DTSTAMP:20240222T090812Z CREATED:20240222T090812Z LAST-MODIFIED:20240222T090812Z UID:10002793-1697464800-1697468400@cmsa.fas.harvard.edu SUMMARY:Breaking ergodicity: quantum scars and regular eigenstates DESCRIPTION:Topological Quantum Matter Seminar \nSpeaker: Ceren Dag\, Harvard \nTitle: Breaking ergodicity: quantum scars and regular eigenstates \nAbstract: Quantum many-body scars (QMBS) consist of a few low-entropy eigenstates in an otherwise chaotic many-body spectrum and can weakly break ergodicity resulting in robust oscillatory dynamics. The notion of QMBS follows the original single-particle scars introduced within the context of quantum billiards\, where scarring manifests in the form of a quantum eigenstate concentrating around an underlying classical unstable periodic orbit (UPO). A direct connection between these notions remains an outstanding problem. Here\, we study a many-body spinor condensate that\, owing to its collective interactions\, is amenable to the diagnostics of scars. We characterize the system’s rich dynamics\, spectrum\, and phase space\, consisting of both regular and chaotic states. The former are low in entropy\, violate the Eigenstate Thermalization Hypothesis (ETH)\, and can be traced back to integrable effective Hamiltonians\, whereas most of the latter are scarred by the underlying semiclassical UPOs\, while satisfying ETH. We outline an experimental proposal to probe our theory in trapped spin-1 Bose-Einstein condensates. If time permits\, I will also mention our latest efforts in introducing spatial dimension to this model with a true semiclassical limit\, and how quantum scars persist to exist in a many-body system. Reference: arXiv 2306.10411\, in peer review. URL:https://cmsa.fas.harvard.edu/event/tqms_101623/ 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-10.16.23.docx-1.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20231018T123000 DTEND;TZID=America/New_York:20231018T133000 DTSTAMP:20240223T113334Z CREATED:20240223T113304Z LAST-MODIFIED:20240223T113334Z UID:10002866-1697632200-1697635800@cmsa.fas.harvard.edu SUMMARY:Composite fermions and the fractional quantum anomalous Hall effect DESCRIPTION:Topological Quantum Matter Seminar \nSpeaker: Hart Goldman\, University of Chicago \nTitle: Composite fermions and the fractional quantum anomalous Hall effect \nAbstract: Recent experiments have revealed evidence for fractional quantum anomalous Hall (FQAH) states at zero magnetic field in a growing number of moire materials. In this talk\, I will argue that a composite fermion description\, already a unifying framework for the phenomenology of 2d electron gases at high magnetic fields\, provides a similarly powerful perspective in this new zero-field context. In particular\, a central prediction of the composite fermion framework is a non-Fermi liquid metal of composite fermions at even-denominator fillings. To this end\, I will present exact diagonalization evidence for such composite Fermi liquid states at zero magnetic field in twisted MoTe2 bilayers\, at fillings n = 1/2 and n = 3/4. Dubbing these states anomalous composite Fermi liquids (ACFLs)\, I will argue that they play a central organizing role in the FQAH phase diagram. I will also develop a long wavelength theory for this ACFL state\, which offers concrete experimental predictions that I will discuss in relation to current measurements. For example\, upon doping the composite Fermi sea\, one obtains a Jain sequence of FQAH states consistent with those observed experimentally\, as well as a new type of commensurability oscillations originating from the superlattice potential intrinsic to the system. Finally\, I will discuss opportunities for new physics not possible in quantum Hall systems at finite magnetic field. URL:https://cmsa.fas.harvard.edu/event/tqms_101823/ 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-10.18.23.png END:VEVENT END:VCALENDAR