Solvable models for 2+1D quantum critical points: Loop soups of 1+1D conformal field theories
Abstract: We construct a class of solvable models for 2+1D quantum critical points by attaching 1+1D conformal field theories (CFTs) to fluctuating domain walls forming a loop soup''. Specifically, our local Hamiltonian attaches gapless spin chains to the domain walls of a triangular lattice Ising antiferromagnet. The macroscopic degeneracy between antiferromagnetic configurations is split by the Casimir energy of each decorating CFT, which is usually negative and thus favors a short loop phase with a finite gap. However, we found a set of 1D CFT Hamiltonians for which the Casimir energy is effectively positive, making it favorable for domain walls to coalesce into a singlesnake'' which is macroscopically long and thus hosts a CFT with a vanishing gap. The snake configurations are geometrical objects also known as fully-packed self-avoiding walks or Hamiltonian walks which are described by an $\mathrm{O}(n=0)$ loop ensemble with a non-unitary 2+0D CFT description. Combining this description with the 1+1D decoration CFT, we obtain a 2+1D theory with unusual critical exponents and entanglement properties. Regarding the latter, we show that the $\log$ contributions from the decoration CFTs conspire with the spatial distribution of loops crossing the entanglement cut to generate a ``non-local area law''. Our predictions are verified by Monte Carlo simulations.
- Xie Chen, Zheng-Cheng Gu, and Xiao-Gang Wen, “Classification of gapped symmetric phases in one-dimensional spin systems,” Phys. Rev. B 83, 035107 (2011a).
- Xie Chen, Zheng-Cheng Gu, and Xiao-Gang Wen, “Complete classification of one-dimensional gapped quantum phases in interacting spin systems,” Phys. Rev. B 84, 235128 (2011b).
- Xie Chen, Zheng-Xin Liu, and Xiao-Gang Wen, “Two-dimensional symmetry-protected topological orders and their protected gapless edge excitations,” Phys. Rev. B 84, 235141 (2011c).
- Zheng-Cheng Gu and Xiao-Gang Wen, “Tensor-entanglement-filtering renormalization approach and symmetry-protected topological order,” Phys. Rev. B 80, 155131 (2009a).
- Frank Pollmann, Ari M. Turner, Erez Berg, and Masaki Oshikawa, “Entanglement spectrum of a topological phase in one dimension,” Phys. Rev. B 81, 064439 (2010).
- Lukasz Fidkowski and Alexei Kitaev, “Topological phases of fermions in one dimension,” Phys. Rev. B 83, 075103 (2011).
- Ari M. Turner, Frank Pollmann, and Erez Berg, “Topological phases of one-dimensional fermions: An entanglement point of view,” Phys. Rev. B 83, 075102 (2011).
- Yuan-Ming Lu and Ashvin Vishwanath, “Theory and classification of interacting integer topological phases in two dimensions: A chern-simons approach,” Phys. Rev. B 86, 125119 (2012).
- Michael Levin and Zheng-Cheng Gu, “Braiding statistics approach to symmetry-protected topological phases,” Phys. Rev. B 86, 115109 (2012).
- Dominic V. Else and Chetan Nayak, “Classifying symmetry-protected topological phases through the anomalous action of the symmetry on the edge,” Phys. Rev. B 90, 235137 (2014).
- Xie Chen, Zheng-Cheng Gu, Zheng-Xin Liu, and Xiao-Gang Wen, “Symmetry protected topological orders and the group cohomology of their symmetry group,” Phys. Rev. B 87, 155114 (2013).
- J. P. Kestner, Bin Wang, Jay D. Sau, and S. Das Sarma, “Prediction of a gapless topological haldane liquid phase in a one-dimensional cold polar molecular lattice,” Phys. Rev. B 83, 174409 (2011).
- Lukasz Fidkowski, Roman M. Lutchyn, Chetan Nayak, and Matthew P. A. Fisher, “Majorana zero modes in one-dimensional quantum wires without long-ranged superconducting order,” Phys. Rev. B 84, 195436 (2011).
- Anna Keselman and Erez Berg, “Gapless symmetry-protected topological phase of fermions in one dimension,” Phys. Rev. B 91, 235309 (2015).
- Thomas Scaffidi, Daniel E. Parker, and Romain Vasseur, “Gapless symmetry-protected topological order,” Phys. Rev. X 7, 041048 (2017).
- Daniel E. Parker, Thomas Scaffidi, and Romain Vasseur, “Topological luttinger liquids from decorated domain walls,” Phys. Rev. B 97, 165114 (2018).
- Ruben Verresen, Nick G. Jones, and Frank Pollmann, “Topology and edge modes in quantum critical chains,” Phys. Rev. Lett. 120, 057001 (2018).
- Daniel E. Parker, Romain Vasseur, and Thomas Scaffidi, “Topologically protected long edge coherence times in symmetry-broken phases,” Phys. Rev. Lett. 122, 240605 (2019).
- Ruben Verresen, Ryan Thorngren, Nick G. Jones, and Frank Pollmann, “Gapless topological phases and symmetry-enriched quantum criticality,” Phys. Rev. X 11, 041059 (2021).
- Ryan Thorngren, Ashvin Vishwanath, and Ruben Verresen, “Intrinsically gapless topological phases,” Phys. Rev. B 104, 075132 (2021).
- Ruochen Ma, Liujun Zou, and Chong Wang, “Edge physics at the deconfined transition between a quantum spin Hall insulator and a superconductor,” SciPost Phys. 12, 196 (2022).
- Carolyn Zhang and Michael Levin, “Exactly solvable model for a deconfined quantum critical point in 1d,” Phys. Rev. Lett. 130, 026801 (2023).
- Rui Wen and Andrew C. Potter, “Bulk-boundary correspondence for intrinsically-gapless spts from group cohomology,” (2023), arXiv:2208.09001 [cond-mat.str-el] .
- Xie Chen, Yuan-Ming Lu, and Ashvin Vishwanath, “Symmetry-protected topological phases from decorated domain walls,” Nature Communications 5, 3507 (2014).
- Masafumi Udagawa, Hiroaki Ishizuka, and Yukitoshi Motome, “Quantum melting of charge ice and non-fermi-liquid behavior: An exact solution for the extended falicov-kimball model in the ice-rule limit,” Phys. Rev. Lett. 104, 226405 (2010).
- A. Hemmatzade, K. Essafi, M. Taillefumier, M. Müller, T. Fennell, and P. M. Derlet, “Fluctuation-induced spin nematic order in magnetic charge-ice,” arXiv e-prints , arXiv:2311.05004 (2023), arXiv:2311.05004 [cond-mat.stat-mech] .
- Lucile Savary, “Quantum loop states in spin-orbital models on the honeycomb lattice,” Nature Communications 12, 3004 (2021).
- Frank Pollmann, Krishanu Roychowdhury, Chisa Hotta, and Karlo Penc, “Interplay of charge and spin fluctuations of strongly interacting electrons on the kagome lattice,” Phys. Rev. B 90, 035118 (2014).
- Didier Poilblanc, Karlo Penc, and Nic Shannon, “Doped singlet-pair crystal in the hubbard model on the checkerboard lattice,” Phys. Rev. B 75, 220503 (2007).
- V. J. Emery, S. A. Kivelson, and O. Zachar, “Spin-gap proximity effect mechanism of high-temperature superconductivity,” Phys. Rev. B 56, 6120–6147 (1997).
- S. A. Kivelson, E. Fradkin, and V. J. Emery, “Electronic liquid-crystal phases of a doped mott insulator,” Nature 393, 550–553 (1998).
- Ranjan Mukhopadhyay, C. L. Kane, and T. C. Lubensky, “Sliding luttinger liquid phases,” Phys. Rev. B 64, 045120 (2001).
- Bodo Huckestein, “Scaling theory of the integer quantum hall effect,” Rev. Mod. Phys. 67, 357–396 (1995).
- Nabil Iqbal and John McGreevy, “Toward a 3d ising model with a weakly-coupled string theory dual,” SciPost Phys. 9, 019 (2020).
- Eduardo Fradkin, Mark Srednicki, and Leonard Susskind, “Fermion representation for the Z2subscript𝑍2{Z}_{2}italic_Z start_POSTSUBSCRIPT 2 end_POSTSUBSCRIPT lattice gauge theory in 2+1 dimensions,” Phys. Rev. D 21, 2885–2891 (1980).
- Alexander M. Polyakov, Gauge Fields and Strings, Vol. 3 (1987).
- Jacques Distler, “A note on the three-dimensional ising model as a string theory,” Nuclear Physics B 388, 648–670 (1992).
- J. Polchinski, String theory. Vol. 2: Superstring theory and beyond, Cambridge Monographs on Mathematical Physics (Cambridge University Press, 2007).
- H. W. J. Blöte and B. Nienhuis, “Fully packed loop model on the honeycomb lattice,” Phys. Rev. Lett. 72, 1372–1375 (1994).
- Jané Kondev, Jan de Gier, and Bernard Nienhuis, “Operator spectrum and exact exponents of the fully packed loop model,” Journal of Physics A: Mathematical and General 29, 6489 (1996).
- L. D. C. Jaubert, M. Haque, and R. Moessner, “Analysis of a fully packed loop model arising in a magnetic coulomb phase,” Phys. Rev. Lett. 107, 177202 (2011).
- Meng Cheng and Nathan Seiberg, “Lieb-Schultz-Mattis, Luttinger, and ’t Hooft - anomaly matching in lattice systems,” SciPost Phys. 15, 051 (2023).
- G. H. Wannier, “Antiferromagnetism. the triangular ising net,” Phys. Rev. 79, 357–364 (1950).
- We use a convention in which the CFT velocity is 2.
- Note that this 1D Hamiltonian has single and three-body terms, whereas the example given in Eq. 1 was for two-body terms. A generalization of Eq. 1 for single and three-body terms is given in Appendix A.
- Lokman Tsui, Yen-Ta Huang, Hong-Chen Jiang, and Dung-Hai Lee, “The phase transitions between zn×zn bosonic topological phases in 1+1d, and a constraint on the central charge for the critical points between bosonic symmetry protected topological phases,” Nuclear Physics B 919, 470–503 (2017).
- A quantum phase transition with the same universality also could also appear in spin-1 chain models which are relevant for a number of materials like CsNiCl3 Buyers et al. (1986) and Y2BaNiO5 Xu et al. (1996), in which case it separates the Haldane phase Haldane (1983) from a topologically trivial phase. We discuss this spin-1 model in Appendix C).
- We note that Eq. 5 also describes the edge theory of a 2D Z2subscript𝑍2Z_{2}italic_Z start_POSTSUBSCRIPT 2 end_POSTSUBSCRIPT SPT Levin and Gu (2012).
- This mod 4 effect can be understood at a simple level: as explained in Appendix B, the model can be solved by performing a Jordan-Wigner whereby the Ising domain walls become fermions. Because the number of domain walls is restricted to be even for periodic boundary conditions, so is the number of fermions. This means only chains of L=4k𝐿4𝑘L=4kitalic_L = 4 italic_k can be at exactly half-filling, and the other ones are thus “frustrated” and have a higher energy density.
- M. T. Batchelor, J. Suzuki, and C. M. Yung, “Exact results for hamiltonian walks from the solution of the fully packed loop model on the honeycomb lattice,” Phys. Rev. Lett. 73, 2646–2649 (1994).
- The zero-T𝑇Titalic_T limit needs to be taken after the thermodynamic limit, as discussed below.
- John Stephenson, “Ising Model Spin Correlations on the Triangular Lattice,” Journal of Mathematical Physics 5, 1009–1024 (2004), https://pubs.aip.org/aip/jmp/article-pdf/5/8/1009/8174336/1009_1_online.pdf .
- Daniel S. Rokhsar and Steven A. Kivelson, “Superconductivity and the quantum hard-core dimer gas,” Phys. Rev. Lett. 61, 2376–2379 (1988).
- Eddy Ardonne, Paul Fendley, and Eduardo Fradkin, “Topological order and conformal quantum critical points,” Annals of Physics 310, 493–551 (2004).
- S. V. Isakov, P. Fendley, A. W. W. Ludwig, S. Trebst, and M. Troyer, “Dynamics at and near conformal quantum critical points,” Phys. Rev. B 83, 125114 (2011).
- Wei Zhang, Timothy M. Garoni, and Youjin Deng, “A worm algorithm for the fully-packed loop model,” Nuclear Physics B 814, 461–484 (2009).
- Qingquan Liu, Youjin Deng, and Timothy M. Garoni, “Worm monte carlo study of the honeycomb-lattice loop model,” Nuclear Physics B 846, 283–315 (2011).
- Andrew Smerald, Sergey Korshunov, and Frédéric Mila, “Topological aspects of symmetry breaking in triangular-lattice ising antiferromagnets,” Phys. Rev. Lett. 116, 197201 (2016).
- Shankar Balasubramanian, Ethan Lake, and Soonwon Choi, “2D Hamiltonians with exotic bipartite and topological entanglement,” arXiv e-prints , arXiv:2305.07028 (2023), arXiv:2305.07028 [quant-ph] .
- Pasquale Calabrese and John Cardy, “Entanglement entropy and quantum field theory,” Journal of Statistical Mechanics: Theory and Experiment 2004, P06002 (2004).
- Pasquale Calabrese and John Cardy, “Entanglement entropy and conformal field theory,” Journal of Physics A: Mathematical and Theoretical 42, 504005 (2009).
- Andrea Coser, Luca Tagliacozzo, and Erik Tonni, “On rényi entropies of disjoint intervals in conformal field theory,” Journal of Statistical Mechanics: Theory and Experiment 2014, P01008 (2014).
- Hyejin Ju, Ann B. Kallin, Paul Fendley, Matthew B. Hastings, and Roger G. Melko, “Entanglement scaling in two-dimensional gapless systems,” Phys. Rev. B 85, 165121 (2012).
- Stephen Inglis and Roger G Melko, “Entanglement at a two-dimensional quantum critical point: a t = 0 projector quantum monte carlo study,” New Journal of Physics 15, 073048 (2013).
- Maxime Dupont, Snir Gazit, and Thomas Scaffidi, “From trivial to topological paramagnets: The case of ℤ2subscriptℤ2{\mathbb{Z}}_{2}blackboard_Z start_POSTSUBSCRIPT 2 end_POSTSUBSCRIPT and ℤ23superscriptsubscriptℤ23{\mathbb{Z}}_{2}^{3}blackboard_Z start_POSTSUBSCRIPT 2 end_POSTSUBSCRIPT start_POSTSUPERSCRIPT 3 end_POSTSUPERSCRIPT symmetries in two dimensions,” Phys. Rev. B 103, 144437 (2021a).
- Beni Yoshida, “Gapped boundaries, group cohomology and fault-tolerant logical gates,” Annals of Physics 377, 387–413 (2017).
- Beni Yoshida, “Topological phases with generalized global symmetries,” Phys. Rev. B 93, 155131 (2016).
- Thomas Scaffidi and Zohar Ringel, “Wave functions of symmetry-protected topological phases from conformal field theories,” Phys. Rev. B 93, 115105 (2016).
- Maxime Dupont, Snir Gazit, and Thomas Scaffidi, “Evidence for deconfined u(1)𝑢1u(1)italic_u ( 1 ) gauge theory at the transition between toric code and double semion,” Phys. Rev. B 103, L140412 (2021b).
- Nathanan Tantivasadakarn, Ryan Thorngren, Ashvin Vishwanath, and Ruben Verresen, “Building models of topological quantum criticality from pivot Hamiltonians,” SciPost Phys. 14, 013 (2023).
- Ruochen Ma and Chong Wang, “Average symmetry-protected topological phases,” Phys. Rev. X 13, 031016 (2023).
- Jian-Hao Zhang, Yang Qi, and Zhen Bi, “Strange Correlation Function for Average Symmetry-Protected Topological Phases,” arXiv e-prints , arXiv:2210.17485 (2022), arXiv:2210.17485 [cond-mat.str-el] .
- Zhehao Dai and Adam Nahum, “Quantum criticality of loops with topologically constrained dynamics,” Phys. Rev. Res. 2, 033051 (2020).
- Lukas Haller, Wen-Tao Xu, Yu-Jie Liu, and Frank Pollmann, “Quantum phase transition between symmetry enriched topological phases in tensor-network states,” arXiv e-prints , arXiv:2305.02432 (2023), arXiv:2305.02432 [cond-mat.str-el] .
- Xiao-Yong Feng, Guang-Ming Zhang, and Tao Xiang, “Topological characterization of quantum phase transitions in a spin-1/2121/21 / 2 model,” Phys. Rev. Lett. 98, 087204 (2007).
- Han-Dong Chen and Zohar Nussinov, “Exact results of the kitaev model on a hexagonal lattice: spin states, string and brane correlators, and anyonic excitations,” Journal of Physics A: Mathematical and Theoretical 41, 075001 (2008).
- Kai Sun, Benjamin M. Fregoso, Michael J. Lawler, and Eduardo Fradkin, “Fluctuating stripes in strongly correlated electron systems and the nematic-smectic quantum phase transition,” Phys. Rev. B 78, 085124 (2008).
- Matthew Fishman, Steven R. White, and E. Miles Stoudenmire, “The ITensor Software Library for Tensor Network Calculations,” SciPost Phys. Codebases , 4 (2022).
- W. J. L Buyers, R. M. Morra, R. L. Armstrong, M. J. Hogan, P. Gerlach, and K. Hirakawa, “Experimental evidence for the haldane gap in a spin-1 nearly isotropic, antiferromagnetic chain,” Phys. Rev. Lett. 56, 371–374 (1986).
- Guangyong Xu, J. F. DiTusa, T. Ito, K. Oka, H. Takagi, C. Broholm, and G. Aeppli, “y2subscripty2{\mathrm{y}}_{2}roman_y start_POSTSUBSCRIPT 2 end_POSTSUBSCRIPTbanio5subscripto5{\mathrm{o}}_{5}roman_o start_POSTSUBSCRIPT 5 end_POSTSUBSCRIPT: A nearly ideal realization of the s=1𝑠1s=1italic_s = 1 heisenberg chain with antiferromagnetic interactions,” Phys. Rev. B 54, R6827–R6830 (1996).
- F. D. M. Haldane, “Continuum dynamics of the 1-D Heisenberg antiferromagnet: Identification with the O(3) nonlinear sigma model,” Physics Letters A 93, 464–468 (1983).
- Ian Affleck, Tom Kennedy, Elliott H. Lieb, and Hal Tasaki, “Rigorous results on valence-bond ground states in antiferromagnets,” Phys. Rev. Lett. 59, 799–802 (1987).
- Frank Pollmann and Ari M. Turner, “Detection of symmetry-protected topological phases in one dimension,” Phys. Rev. B 86, 125441 (2012).
- Zheng-Cheng Gu and Xiao-Gang Wen, “Tensor-entanglement-filtering renormalization approach and symmetry-protected topological order,” Phys. Rev. B 80, 155131 (2009b).
- Hal Tasaki, Physics and Mathematics of Quantum Many-Body Systems (Springer Nature Switzerland AG, 2020).
- T. Giamarchi, Quantum Physics in One Dimension, International Series of Monographs on Physics (Clarendon Press, 2004).
- Anon (https://math.stackexchange.com/users/245264/anon), “Size of closed loop on a (bipartite) hexagonal lattice with equal number of enclosed a and b sublattice sites.” Mathematics Stack Exchange, uRL:https://math.stackexchange.com/q/1726610 (version: 2016-04-03), https://math.stackexchange.com/q/1726610 .
- John Cardy, “Linking numbers for self-avoiding loops and percolation: Application to the spin quantum hall transition,” Phys. Rev. Lett. 84, 3507–3510 (2000).
- S. Redner, “A First Look at First-Passage Processes,” arXiv e-prints , arXiv:2201.10048 (2022), arXiv:2201.10048 [cond-mat.stat-mech] .
- Nicolas Laflorencie, Erik S. Sørensen, Ming-Shyang Chang, and Ian Affleck, “Boundary effects in the critical scaling of entanglement entropy in 1d systems,” Phys. Rev. Lett. 96, 100603 (2006).
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