Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session S25: Topological Order |
Hide Abstracts |
Sponsoring Units: DCMP Chair: Carolyn Zhang, University of Chicago Room: Room 217/218 |
Thursday, March 9, 2023 8:00AM - 8:12AM |
S25.00001: Detecting anyons using nonlinear pump-probe spectroscopy Max McGinley, Michele Fava, Siddharth A Parameswaran Topologically ordered two-dimensional systems can host excitations that possess statistics that interpolate between bosonic and fermionic---so called anyons. In this talk, I will explain how the presence of such anyonic excitations can be inferred from nonlinear spectroscopic quantities. In particular, we consider pump-probe spectroscopy, where a sample is irradiated by two light pulses with an adjustable time delay between them. The relevant response coefficient exhibits a universal form that originates from the statistical phase acquired when anyons created by the first pulse braid around those created by the second. This behaviour is shown to be qualitatively unchanged by non-universal physics including non-statistical interactions and small finite temperatures. In magnetic systems, the signal of interest can be measured using currently available terahertz-domain probes, highlighting the potential usefulness of nonlinear spectroscopic techniques in the search for quantum spin liquids. |
Thursday, March 9, 2023 8:12AM - 8:24AM |
S25.00002: Thermal interferometry of anyons Zezhu Wei, Navketan Batra, Vesna F Mitrovic, D. E Feldman Anyonic interferometry probes the braiding phases of excitations in topologically ordered matter. This technique is well established for charged quasiparticles in the fractional quantum Hall effect. We propose to extend it to neutral anyons, such as Ising anyons in Kitaev magnets and quasiparticles in other neutral spin liquids. We find that the thermal current through an interferometer is sensitive to the statistics of tunneling quasiparticles. We present a systematic investigation of signatures of various Abelian and non-Abelian topological orders in Fabry-Pérot and Mach-Zehnder interferemeters. Furthermore, we identify another probe of topological order that involves the scaling of the thermal current through a single tunneling contact at low temperatures. The current shows a universal temperature dependence, sensitive to the topological order in the system. |
Thursday, March 9, 2023 8:24AM - 8:36AM |
S25.00003: Ground state degeneracy on torus in topologially ordered phases Haruki Watanabe, Yohei Fuji, Meng Cheng Topologically-ordered phases in $2+1$ dimensions are generally characterized by three mutually-related features: |
Thursday, March 9, 2023 8:36AM - 8:48AM |
S25.00004: System with Z2 local gauge in the presence of U(1) global symmetry Kai-Hsin Wu, Alexey Khudorozhkov, Guilherme Delfino Silva, Anders W Sandvik, Dmitry Green, Claudio Chamon Systems with local gauge symmetries host topological orders. Here we study a system with a local gauge symmetry supplemented by a global symmetry and its associated conserved charge. We investigate a generalization of Kitaev's toric code on a square lattice, which has both local Z2 gauge symmetry and global U(1) symmetry. Using quantum Monte Carlo simulation, we find that the system is gapped, and the ground state shows coexistence of symmetry breaking and topologically ordered phases. For different compactifications of the lattice, we find that the topological degeneracy changes. The microscopic details of the lattice arrangement affecting the topological degeneracy demonstrate a UV/IR mixing in this model. |
Thursday, March 9, 2023 8:48AM - 9:00AM |
S25.00005: Correlated topological states and phase diagram of doped Kitaev materials under strong magnetic fields Cheong Eung Ahn, Gil Young Cho Motivated by recent experiments on proximately coupled graphene and α-RuCl3, we theoretically investigate the global phase diagram of a slightly doped Kitaev spin liquid under a strong magnetic field vertical to the lattice plane. This system can potentially realize strongly correlated topological states with exotic anyon contents, where the fractional quantum Hall fluids coexist with the magnetically stabilized chiral spin liquid. Performing variational Monte Carlo calculations combined with effective topological field theory descriptions, we find multiple Abelian and non-Abelian topological phases. We also discuss how these states can be accessed and detected in experiments. |
Thursday, March 9, 2023 9:00AM - 9:12AM |
S25.00006: Entanglement spectra of (2+1)-dimensional topological spin liquid PEPS and chirality, with a focus on the SU(3)-symmetric case Mark J Arildsen, Ji-Yao Chen, Norbert Schuch, Andreas W Ludwig The wavefunctions of (2+1)D chiral topological phases are often identified by studying low-lying entanglement spectra (ES) on long cylinders of finite circumference. For chiral topological states that possess global SU(3) symmetry, we can now understand the ES through the splitting of degeneracies in the finite-size ES, at a given momentum, solely from conformal field theory (CFT), a finer diagnostic than Li-Haldane "state-counting". We contrast such chiral ES with those of a non-chiral PEPS (Kurecic, Sterdyniak, and Schuch [PRB 99, 045116 (2019)]) with SU(3) symmetry. That PEPS has strong time-reversal and reflection symmetry breaking, but the full analysis of the sectors of the ES in prior work [arXiv:2207.03246] shows its non-chirality, in the sense of having zero chiral central charge. We can then identify a distinct indicator of chirality: the splittings of conjugate irreps. In the chiral ES, conjugate irreps are degenerate, because the operators (related to the cubic Casimir of SU(3)) that would split them are shown to be forbidden. In the non-chiral ES, conjugate splittings are non-negligible and can be calculated. Such a diagnostic simplifies identification of chirality in low-energy finite-size ES for SU(3)-symmetric topological states. |
Thursday, March 9, 2023 9:12AM - 9:24AM |
S25.00007: Bosonization of fermionic categorical symmetries Karan Bhatia Bosonization has proven to be an effective tool in the study of fermionic phases of matter. In this work, we study the bosonization of (1+1)d fermionic lattice systems with a focus on the generalized symmetry. First we bosonize the (1+1)d edge lattice model of a fermionic symmetry-protected topological phase in (2+1)d, and derive how the symmetry and 't Hooft anomaly are represented in the bosonic system. We will then discuss the bosonization map of fermionic categorical symmetries into bosonic categorical symmetries in anyon chains. |
Thursday, March 9, 2023 9:24AM - 9:36AM |
S25.00008: Classification and construction of interacting fractonic higher-order topological phases Zhen Bi, Meng Cheng, Jianhao Zhang Symmetry-protected topological (SPT) phases greatly expand our knowledge of quantum phases of matter beyond the conventional Landau symmetry-breaking paradigm. A common feature of SPT phases is the gapless boundary states due to symmetry protection. However, in contrast to the ordinary topological insulator, recently a new class of SPT phases is shown to exist where symmetry-protected gapless modes only show up on certain low-dimensional submanifolds on the boundary while the majority of the boundary can be gapped without breaking the symmetry. These features defined a new class of SPT phases dubbed higher-order topological phases. We show the notion of higher-order topological phases can have interesting generalizations to systems with subsystem symmetries that exhibit fractonic dynamics for charged excitations. We systematically study the higher-order topological phases protected by a combination of subsystem symmetries and ordinary global symmetries in two and three-dimensional interacting boson systems. From the general classification, we establish a few interesting facts. For instance, Abelian subsystem symmetry has no nontrivial 2-foliated higher-order SSPT phase in (2+1)d systems without the aid of global symmetries. In addition, we prove that for inhomogeneous subsystem symmetries, there is no nontrivial higher-order subsystem SPT phase. Besides the general classification, we also explicitly construct models of such subsystem SPT states in 2 and 3 spatial dimensions. |
Thursday, March 9, 2023 9:36AM - 9:48AM |
S25.00009: Effective Fractonic Behavior in a Two-Dimensional Exactly Solvable Spin Liquid Guilherme Delfino Silva, Claudio Chamon, Pedro Gomes, Weslei Fontana In this work, we propose a ZN clock model which is exactly solvable on the lattice. We find exotic properties for the low-energy physics, such as UV/IR mixing and excitations with restricted mobility, that resemble fractonic physics from higher dimensional models. We then study the continuum descriptions for the lattice system in two distinct regimes and find two qualitative distinct field theories for each one of them. A characteristic time scale that grows exponentially fast with N^2 (and diverges rapidly as function of system parameters) separates these two regimes. For times below this scale, the system is described by an effective fractonic Chern-Simons-like action, where higher-form symmetries prevent quasiparticles from hopping. In this regime, the system behaves effectively as a fracton as isolated particles, in practice, never leave their original position. Beyond the large characteristic time scale, the excitations are mobile and the effective field theory is given by a pure mutual Chern-Simons action. In this regime, the UV/IR properties of the system is captured by a peculiar realization of the translation group. |
Thursday, March 9, 2023 9:48AM - 10:00AM |
S25.00010: Kitaev spin-orbital bilayers and their moire superlattices Emilian M Nica, Muhammad Akram, Aayush Vijayvargia, Roderich Moessner, Onur Erten We determine the phase diagram of a bilayer, Yao-Lee spin-orbital model with inter-layer interactions (J), for several stackings and moire superlattices. For AA stacking, a gapped Z2 quantum spin liquid phase emerges at a finite Jc. We show that this phase survives in the well-controlled large-J limit, where an isotropic honeycomb toric code emerges. For moire superlattices, a finite-q inter-layer hybridization is stabilized. This connects inequivalent Dirac points, effectively `untwisting' the system. Our study thus provides insight into the spin-liquid phases of bilayer spin-orbital Kitaev materials. |
Thursday, March 9, 2023 10:00AM - 10:12AM |
S25.00011: Enforced symmetry breaking: the symmetry constraint in topological phases Shang-Qiang Ning, Yang Qi, Zheng-Cheng Gu, Chenjie Wang The symmetry and topology are two very important aspects of condensed matter physics. In recent years, the interplay between symmetry and topology have brought us great advances in understanding the phases of matter in nature, among which two are celebrated: the Symmetry Protected Topological phase and Symmetry Enriched Topological phase. In the usual classification and construction theory, the symmetry is assumed to be compatible with the underlying topological order with long range entanglement structure. However, there could exsist situations that the symmetry are always incompatible with the underlying long range entanglement structure, i.e., topological order, which leads to a interesting phenomenon---enforced symmetry breaking by topological order. aIn this talk, we will review the concept of enforced symmetry breaking by the invertible topological order, and then generalize to other systems. |
Thursday, March 9, 2023 10:12AM - 10:24AM |
S25.00012: Quantum Spin Lakes: NISQ-Era Spin Liquids from Non-Equilibrium Dynamics Rahul Sahay, Ruben Verresen, Ashvin Vishwanath Abstract: Ground states of many-body quantum systems can potentially host long-ranged entangled states known as quantum spin liquids (QSLs). The requirements for realizing such equilibrium states are rather demanding, including strong quantum resonances in the Hamiltonian and the ability to cool below the energy gap. Here, we show how non-equilibrium dynamics can provide a more streamlined route toward creating QSLs. By first focusing on the simplest $mathbb{Z}_2$ toric code spin liquid, with gapped charge and flux excitations, we outline a dynamical protocol that begins in the short-range entangled ``Higgs'' phase and proceeds to sweep parameters to remove the condensed charge excitations. When there is a separation of scales between the motion of charge ($e$-anyons) and flux ($m$-anyons) excitations, we identify a dynamical regime in which the sweep is quasi-adiabatic with respect to the charge but sudden with respect to flux. Targeting this regime we demonstrate robust preparation of the spin liquid state in finite-sized regions, which we brand ``quantum spin lakes''. 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. We conclude by highlighting two striking consequences of our theory. First, we emphasize that paradoxically, the absence---rather than presence---of quantum resonances aid in stabilizing the dynamical preparation of quantum spin liquids. This leads us to recognize that the dynamics observed experimentally and in full-scale numerics are well approximated by tree tensor network simulations of tree lattices. Finally, we highlight that even spin liquid states that are unstable in equilibrium---namely, $2 + 1$D $U(1)$ spin liquid states---can be stably prepared by non-equilibrium dynamics. |
Thursday, March 9, 2023 10:24AM - 10:36AM |
S25.00013: Topological order from finite-depth unitaries, measurement and feedforward: Part I Nathanan Tantivasadakarn, Ruben Verresen, Ashvin Vishwanath Long-range entanglement -- the backbone of topologically ordered states -- cannot be created in finite time using local unitary circuits, or equivalently, adiabatic state preparation. Recently it has come to light that single-site measurements provide a loophole, allowing for finite-time state preparation in certain cases. I will explore how this observation imposes a complexity hierarchy on long-range entangled states based on the minimal number of measurement layers required to create the state. I will argue that certain phases of matter cannot be prepared using any finite number of layers, while remarkably certain non-Abelian topological orders can be prepared in a single round of measurement. The ingredients to implement such protocols are readily available in current NISQ devices. |
Thursday, March 9, 2023 10:36AM - 10:48AM |
S25.00014: Topological order from finite-depth unitaries, measurement and feedforward: Part II Ruben Verresen, Ashvin Vishwanath, Nathanan Tantivasadakarn Long-range entanglement -- the backbone of topologically ordered states -- cannot be created in finite time using local unitary circuits, or equivalently, adiabatic state preparation. Recently it has come to light that single-site measurements provide a loophole, allowing for finite-time state preparation in certain cases. I will explore how this observation imposes a complexity hierarchy on long-range entangled states based on the minimal number of measurement layers required to create the state. I will argue that certain phases of matter cannot be prepared using any finite number of layers, while remarkably certain non-Abelian topological orders can be prepared in a single round of measurement. The ingredients to implement such protocols are readily available in current NISQ devices. |
Thursday, March 9, 2023 10:48AM - 11:00AM |
S25.00015: Elementary derivation of the stacking rules of invertible fermionic topological phases in one dimension Ömer Mert Aksoy, Christopher M Mudry Invertible fermionic topological (IFT) phases are gapped phases of matter with nondegenerate ground states on any closed spatial manifold. When open boundary conditions are imposed, nontrivial IFT phases support gapless boundary degrees of freedom. Distinct IFT phases in one-dimensional space with an internal symmetry group Gf have been characterized by a triplet of indices ([(ν,ρ)],[μ]). IFT phases of matter form an Abelian group structure under the operation of ''stacking''. In this talk, I will first give an operational definition of the indices ([(ν,ρ)],[μ]) from the perspective of the boundary. I will then show an elementary derivation of the stacking rules of IFT phases with any symmetry group Gf , i.e., I will provide an explicit formula for ([(νΛ,ρΛ)],[μΛ]) that is obtained from stacking two IFT phases characterized by the triplets of boundary indices ([(ν1,ρ1)],[μ1]) and ([(ν2,ρ2)],[μ2]). |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700