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DTSTART;TZID=America/New_York:20230203T103000
DTEND;TZID=America/New_York:20230203T113000
DTSTAMP:20260601T131143
CREATED:20230802T164259Z
LAST-MODIFIED:20240215T100905Z
UID:10001166-1675420200-1675423800@cmsa.fas.harvard.edu
SUMMARY:Fracton orders in hyperbolic space and its excitations with fractal mobility
DESCRIPTION:Quantum Matter Seminar \nSpeaker: Han Yan (Rice U) \nTitle: Fracton orders in hyperbolic space and its excitations with fractal mobility \nAbstract: Unlike ordinary topological quantum phases\, fracton orders are intimately dependent on the underlying lattice geometry. In this work\, we study a generalization of the X-cube model\, on lattices embedded in a stack of hyperbolic planes. We demonstrate that for certain hyperbolic lattice tesselations\, this model hosts a new kind of subdimensional particle\, treeons\, which can only move on a fractal-shaped subset of the lattice. Such an excitation only appears on hyperbolic geometries; on flat spaces\, treeons become either a lineon or a planeon. Additionally\, we find intriguingly that for certain hyperbolic tessellations\, a fracton can be created by a membrane operator (as in the X-cube model) or by a fractal-shaped operator within the hyperbolic plane. Our work shows that there are still plenty of exotic behaviors from fracton order to be explored\, especially when the embedding geometry is curved. \nReference: H. Yan\, K. Slage\, A. H. Nevidomskyy\, arXiv:2211.15829 \n 
URL:https://cmsa.fas.harvard.edu/event/qm_2323/
LOCATION:Virtual
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QMMP-02.03.23.png
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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20230210T103000
DTEND;TZID=America/New_York:20230210T113000
DTSTAMP:20260601T131143
CREATED:20230802T164450Z
LAST-MODIFIED:20240216T083704Z
UID:10001167-1676025000-1676028600@cmsa.fas.harvard.edu
SUMMARY:Non-invertible Symmetry Enforced Gaplessness
DESCRIPTION:Quantum Matter Seminar \nSpeaker: Ho Tat Lam (MIT) \nTitle: Non-invertible Symmetry Enforced Gaplessness \nAbstract: Quantum systems in 3+1-dimensions that are invariant under gauging a one-form symmetry enjoy novel non-invertible duality symmetries encoded by topological defects. These symmetries are renormalization group invariants which constrain infrared dynamics. We show that such non-invertible symmetries often forbid a symmetry-preserving vacuum state with a gapped spectrum\, leaving only two possibilities for the infrared dynamics: a gapless state or spontaneous breaking of the non-invertible symmetries. These non-invertible symmetries are realized in lattice gauge theories\, which serve to illustrate our results. \n 
URL:https://cmsa.fas.harvard.edu/event/qm_21023/
LOCATION:Virtual
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QMMP-02.10.23.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20230217T100000
DTEND;TZID=America/New_York:20230217T113000
DTSTAMP:20260601T131143
CREATED:20230802T164725Z
LAST-MODIFIED:20240813T161921Z
UID:10001168-1676628000-1676633400@cmsa.fas.harvard.edu
SUMMARY:Quantum Spin Lakes: NISQ-Era Spin Liquids from Non-Equilibrium Dynamics
DESCRIPTION:Quantum Matter Seminar \nSpeaker: Rahul Sahay (Harvard) \nTitle: Quantum Spin Lakes: NISQ-Era Spin Liquids from Non-Equilibrium Dynamics \nAbstract: While many-body quantum systems can in principle host exotic quantum spin liquid (QSL) states\, realizing them as ground states in experiments can be prohibitively difficult. In this talk\, we show how non-equilibrium dynamics can provide a streamlined route toward creating QSLs. In particular\, we show how a simple Hamiltonian parameter sweep can dynamically project out condensed anyons from a family of initial product states (e.g. dynamically “un-Higgs”)\, yielding a QSL-like state. We christen such states “quantum spin lakes” which\, while not thermodynamically large QSLs\, enable their study in NISQ-era quantum simulators. Indeed\, we show that this mechanism sheds light on recent experimental and numerical observations of the dynamical state preparation of the ruby lattice spin liquid in Rydberg atom arrays. Time permitting\, we will discuss how our theory motivates a tree tensor network-based numerical tool—reliant on our theory—that quantitatively reproduces the experimental data two orders of magnitude faster than conventional brute-force simulation methods. Finally\, we will highlight that even spin liquid states that are unstable in equilibrium—namely\, 2 + 1D U(1) spin liquid states—can be robustly prepared by non-equilibrium dynamics. \n 
URL:https://cmsa.fas.harvard.edu/event/qm_21723/
LOCATION:Virtual
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QMMP-02.17.23.png
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