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Publications (10 of 47) Show all publications
Borla, U., Gazit, S. & Moroz, S. (2024). Deconfined quantum criticality in Ising gauge theory entangled with single-component fermions [Letter to the editor]. Physical Review B, 110(20), Article ID L201110.
Open this publication in new window or tab >>Deconfined quantum criticality in Ising gauge theory entangled with single-component fermions
2024 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 110, no 20, article id L201110Article in journal, Letter (Refereed) Published
Abstract [en]

We highlight the exotic quantum criticality of quasi-two-dimensional single-component fermions at half filling that are minimally coupled to a dynamical Ising gauge theory. With the numerical matrix product state based infinite density matrix renormalization group method, we discover a robust quantum critical line in the infinite cylinder geometry, where gauge confinement and dimerized translation symmetry breaking emerge simultaneously. We investigate how the transition can be split by a Z2 topologically ordered dimerized phase that is stabilized by additional short-range repulsive interactions. We conjecture a u(1) deconfined criticality scenario, propose a corresponding low-energy effective field theory of the exotic quantum critical point in the two-dimensional limit, and identify its shortcomings. 

Place, publisher, year, edition, pages
American Physical Society, 2024
Keywords
Cylinders (shapes), Decoding, Gages, Ising model, Matrix algebra, Quantum optics, Density matrix renormalization group methods, Gauge theory, Half-filling, Matrix product state, Numerical matrices, Quantum critical, Quantum criticality, Single components, State based, Two-dimensional, Quantum entanglement
National Category
Condensed Matter Physics
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-102454 (URN)10.1103/PhysRevB.110.L201110 (DOI)001361274100003 ()2-s2.0-85210133128 (Scopus ID)
Funder
The Swedish Foundation for International Cooperation in Research and Higher Education (STINT)Swedish Research Council, 2021-03685
Available from: 2024-12-11 Created: 2024-12-11 Last updated: 2024-12-11Bibliographically approved
Du, Y.-H., Moroz, S., Nguyen, D. X. & Son, D. T. (2024). Noncommutative field theory of the Tkachenko mode: Symmetries and decay rate [Letter to the editor]. Physical Review Research, 6(1), Article ID L012040.
Open this publication in new window or tab >>Noncommutative field theory of the Tkachenko mode: Symmetries and decay rate
2024 (English)In: Physical Review Research, E-ISSN 2643-1564, Vol. 6, no 1, article id L012040Article in journal, Letter (Refereed) Published
Abstract [en]

We construct an effective field theory describing the collective Tkachenko oscillation mode of a vortex lattice in a two-dimensional rotating Bose-Einstein condensate in the long-wavelength regime. The theory has the form of a noncommutative field theory of a Nambu-Goldstone boson, which exhibits a noncommutative version of dipole symmetry. From the effective field theory, we show that, at zero temperature, the decay width Γ of the Tkachenko mode scales with its energy E as Γ∼E3 in the low-energy limit. We also discuss the width of the Tkachenko mode at a small temperature.

Place, publisher, year, edition, pages
American Physical Society, 2024
Keywords
Bose-Einstein condensation, Decay (organic), Lattice theory, Bose-Einstein condensates, Decay rate, Effective field theory, Field theory, Long wavelength, Non-commutative; Oscillation mode; Tkachenko modes, Two-dimensional, Vortex lattices, Statistical mechanics
National Category
Subatomic Physics
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-99151 (URN)10.1103/PhysRevResearch.6.L012040 (DOI)2-s2.0-85186264493 (Scopus ID)
Funder
Swedish Research Council, 2021- 322 03685
Available from: 2024-04-03 Created: 2024-04-03 Last updated: 2024-04-03Bibliographically approved
Nguyen, D. X. & Moroz, S. (2024). On quantum melting of superfluid vortex crystals: From Lifshitz scalar to dual gravity. SciPost Physics, 17(6), Article ID 164.
Open this publication in new window or tab >>On quantum melting of superfluid vortex crystals: From Lifshitz scalar to dual gravity
2024 (English)In: SciPost Physics, E-ISSN 2542-4653, Vol. 17, no 6, article id 164Article in journal (Refereed) Published
Abstract [en]

Despite a long history of studies of vortex crystals in rotating superfluids, their melting due to quantum fluctuations is poorly understood. Here we develop a fracton-elasticity duality to investigate a two-dimensional vortex lattice within the fast rotation regime, where the Lifshitz model of the collective Tkachenko mode serves as the leading-order low-energy effective theory. We incorporate topological defects and discuss several quantum melting scenarios triggered by their proliferation. Furthermore, we lay the groundwork for a dual non-linear emergent gravity description of the superfluid vortex crystals.

Place, publisher, year, edition, pages
SCIPOST FOUNDATION, 2024
National Category
Condensed Matter Physics Atom and Molecular Physics and Optics Other Physics Topics
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-102549 (URN)10.21468/SciPostPhys.17.6.164 (DOI)001375521200002 ()2-s2.0-85212240548 (Scopus ID)
Funder
Swedish Research Council, 2021-03685
Available from: 2024-12-23 Created: 2024-12-23 Last updated: 2025-01-02Bibliographically approved
Seifert, U. F. .. & Moroz, S. (2024). Wegner’s Ising gauge spins versus Kitaev’s Majorana partons: Mapping and application to anisotropic confinement in spin-orbital liquids. SciPost Physics, 16(6), Article ID 147.
Open this publication in new window or tab >>Wegner’s Ising gauge spins versus Kitaev’s Majorana partons: Mapping and application to anisotropic confinement in spin-orbital liquids
2024 (English)In: SciPost Physics, E-ISSN 2542-4653, Vol. 16, no 6, article id 147Article in journal (Refereed) Published
Abstract [en]

Emergent gauge theories take a prominent role in the description of quantum matter, supporting deconfined phases with topological order and fractionalized excitations. A common construction of Z2 lattice gauge theories, first introduced by Wegner, involves Ising gauge spins placed on links and subject to a discrete Z2 Gauss law constraint. As shown by Kitaev, Z2 lattice gauge theories also emerge in the exact solution of certain spin systems with bond-dependent interactions. In this context, the Z2 gauge field is constructed from Majorana fermions, with gauge constraints given by the parity of Majorana fermions on each site. In this work, we provide an explicit Jordan-Wigner transformation that maps between these two formulations on the square lattice, where the Kitaev-type gauge theory emerges as the exact solution of a spin-orbital (Kugel-Khomskii) Hamiltonian. We then apply our mapping to study local perturbations to the spin-orbital Hamiltonian, which correspond to anisotropic interactions between electric-field variables in the Z2 gauge theory. These are shown to induce anisotropic confinement that is characterized by emergence of weakly-coupled one-dimensional spin chains. We study the nature of these phases and corresponding confinement transitions in both absence and presence of itinerant fermionic matter degrees of freedom. Finally, we discuss how our mapping can be applied to the Kitaev spin-1/2 model on the honeycomb lattice. 

Place, publisher, year, edition, pages
SciPost Foundation, 2024
National Category
Condensed Matter Physics
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-100714 (URN)10.21468/SciPostPhys.16.6.147 (DOI)001240740300003 ()2-s2.0-85195885355 (Scopus ID)
Funder
German Research Foundation (DFG), 449890867Swedish Research Council, 2021-03685
Available from: 2024-06-26 Created: 2024-06-26 Last updated: 2024-06-26Bibliographically approved
Kebrič, M., Borla, U., Schollwöeck, U., Moroz, S., Barbiero, L. & Grusdt, F. (2023). Confinement induced frustration in a one-dimensional Z2 lattice gauge theory. New Journal of Physics, 25(1), Article ID 013035.
Open this publication in new window or tab >>Confinement induced frustration in a one-dimensional Z2 lattice gauge theory
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2023 (English)In: New Journal of Physics, E-ISSN 1367-2630, Vol. 25, no 1, article id 013035Article in journal (Refereed) Published
Abstract [en]

Coupling dynamical charges to gauge fields can result in highly non-local interactions with a linear confining potential. As a consequence, individual particles bind into mesons which, in one dimension, become the new constituents of emergent Luttinger liquids (LLs). Furthermore, at commensurate fillings, different Mott-insulating states can be stabilized by including nearest-neighbour (NN) interactions among charges. However, rich phase diagrams expected in such models have not been fully explored and still lack comprehensive theoretical explanation. Here, by combining numerical and analytical tools, we study a simple one-dimensional Z2 lattice gauge theory at half-filling, where U(1) matter is coupled to gauge fields and interacts through NN repulsion. We uncover a rich phase diagram where the local NN interaction stabilizes a Mott state of individual charges (or partons) on the one hand, and an LL of confined mesons on the other. Furthermore, at the interface between these two phases, we uncover a highly frustrated regime arising due to the competition between the local NN repulsion and the non-local confining interactions, realizing a pre-formed parton plasma. Our work is motivated by the recent progress in ultracold atom experiments, where such simple model could be readily implemented. For this reason we calculate the static structure factor which we propose as a simple probe to explore the phase diagram in an experimental setup.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2023
Keywords
quantum gases, lattice gauge theory, quantum simulation, confinement, metal-to-insulator transition
National Category
Condensed Matter Physics
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-93766 (URN)10.1088/1367-2630/acb45c (DOI)000923603500001 ()2-s2.0-85147795522 (Scopus ID)
Funder
German Research Foundation (DFG), EXC-2111-390814868; 277974659, MO 3013/1-1EU, Horizon 2020, 948141Swedish Research Council, 2021-03685
Available from: 2023-02-25 Created: 2023-02-25 Last updated: 2024-01-17Bibliographically approved
Emonts, P., Kelman, A., Borla, U., Moroz, S., Gazit, S. & Zohar, E. (2023). Finding the ground state of a lattice gauge theory with fermionic tensor networks: A 2+1D Z2 demonstration. Physical Review D: covering particles, fields, gravitation, and cosmology, 107(1), Article ID 014505.
Open this publication in new window or tab >>Finding the ground state of a lattice gauge theory with fermionic tensor networks: A 2+1D Z2 demonstration
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2023 (English)In: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 107, no 1, article id 014505Article in journal (Refereed) Published
Abstract [en]

Tensor network states, and in particular projected entangled pair states (PEPS) have been a strong ansatz for the variational study of complicated quantum many-body systems, thanks to their built-in entanglement entropy area law. In this work, we use a special kind of PEPS-gauged Gaussian fermionic PEPS (GGFPEPS)-to find the ground state of 2 thorn 1 dimensional pure Z2 lattice gauge theories for a wide range of coupling constants. We do so by combining PEPS methods with Monte-Carlo computations, allowing for efficient contraction of the PEPS and computation of correlation functions. Previously, such numerical computations involved the calculation of the Pfaffian of a matrix scaling with the system size, forming a severe bottleneck; in this work we show how to overcome this problem. This paves the way for applying the method we propose and benchmark here to other gauge groups, higher dimensions, and models with fermionic matter, in an efficient, sign-problem-free way.

Place, publisher, year, edition, pages
American Physical Society, 2023
National Category
Condensed Matter Physics
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-93250 (URN)10.1103/PhysRevD.107.014505 (DOI)000911212000005 ()2-s2.0-85146315070 (Scopus ID)
Funder
Swedish Research Council, 2021-03685
Available from: 2023-02-02 Created: 2023-02-02 Last updated: 2023-02-13Bibliographically approved
Das, A., Borla, U. & Moroz, S. (2023). Fractionalized holes in one-dimensional Z2 gauge theory coupled to fermion matter: Deconfined dynamics and emergent integrability. Physical Review B, 107(6), Article ID 064302.
Open this publication in new window or tab >>Fractionalized holes in one-dimensional Z2 gauge theory coupled to fermion matter: Deconfined dynamics and emergent integrability
2023 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 107, no 6, article id 064302Article in journal (Refereed) Published
Abstract [en]

We investigate the interplay of quantum one-dimensional discrete Z2 gauge fields and fermion matter near full filling in terms of deconfined fractionalized hole excitations that constitute mobile domain walls between vacua that break spontaneously translation symmetry. In the limit of strong string tension, we uncover emergent integrable correlated hopping dynamics of holes which is complementary to the constrained XXZ description in terms of bosonic dimers. We analyze numerically quantum dynamics of spreading of an isolated hole together with the associated time evolution of entanglement and provide analytical understanding of its salient features. We also study the model enriched with a short-range interaction and clarify the nature of the resulting ground state at low filling of holes and identify deconfined hole excitations near the hole filling νh = 1/3.

Place, publisher, year, edition, pages
American Physical Society, 2023
National Category
Condensed Matter Physics
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-94124 (URN)10.1103/PhysRevB.107.064302 (DOI)000944109400002 ()2-s2.0-85149691313 (Scopus ID)
Funder
Swedish Research Council, 2021-03685
Available from: 2023-04-03 Created: 2023-04-03 Last updated: 2023-04-03Bibliographically approved
Bastianello, A., Borla, U. & Moroz, S. (2022). Fragmentation and Emergent Integrable Transport in the Weakly Tilted Ising Chain. Physical Review Letters, 128(19), Article ID 196601.
Open this publication in new window or tab >>Fragmentation and Emergent Integrable Transport in the Weakly Tilted Ising Chain
2022 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 128, no 19, article id 196601Article in journal (Refereed) Published
Abstract [en]

We investigate emergent quantum dynamics of the tilted Ising chain in the regime of a weak transverse field. Within the leading order perturbation theory, the Hilbert space is fragmented into exponentially many decoupled sectors. We find that the sector made of isolated magnons is integrable with dynamics being governed by a constrained version of the XXZ spin Hamiltonian. As a consequence, when initiated in this sector, the Ising chain exhibits ballistic transport on unexpectedly long timescales. We quantitatively describe its rich phenomenology employing exact integrable techniques such as generalized hydrodynamics. Finally, we initiate studies of integrability-breaking magnon clusters whose leading-order transport is activated by scattering with surrounding isolated magnons.

Place, publisher, year, edition, pages
American Physical Society, 2022
National Category
Condensed Matter Physics
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-91072 (URN)10.1103/PhysRevLett.128.196601 (DOI)000801151800005 ()35622030 (PubMedID)2-s2.0-85130369690 (Scopus ID)
Funder
German Research Foundation (DFG), MO 3013/1-1Swedish Research Council, 2021-03685German Research Foundation (DFG), EXC2111390814868
Available from: 2022-07-01 Created: 2022-07-01 Last updated: 2022-11-02Bibliographically approved
Borla, U., Jeevanesan, B., Pollmann, F. & Moroz, S. (2022). Quantum phases of two-dimensional Z(2) gauge theory coupled to single-component fermion matter. Physical Review B, 105(7), Article ID 075132.
Open this publication in new window or tab >>Quantum phases of two-dimensional Z(2) gauge theory coupled to single-component fermion matter
2022 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 105, no 7, article id 075132Article in journal (Refereed) Published
Abstract [en]

We investigate the rich quantum phase diagram of Wegner's theory of discrete Ising gauge fields interacting with U (1) symmetric single-component fermion matter hopping on a two-dimensional square lattice. In particular limits, the model reduces to (i) pure Z(2) even and odd gauge theories, (ii) free fermions in a static background of deconfined Z(2) gauge fields, and (iii) the kinetic Rokhsar-Kivelson quantum dimer model at a generic dimer filling. We develop a local transformation that maps the lattice gauge theory onto a model of Z(2) gauge-invariant spin 1/2 degrees of freedom. Using the mapping, we perform numerical density matrix renormalization group calculations that corroborate our understanding of the limits identified above. Moreover, in the absence of the magnetic plaquette term, we reveal signatures of topologically ordered Dirac semimetal and staggered Mott insulator phases at half filling. At strong coupling, the lattice gauge theory displays fracton phenomenology with isolated fermions being completely frozen and dimers exhibiting restricted mobility. In that limit, we predict that in the ground state, dimers form compact clusters, whose hopping is suppressed exponentially in their size. We determine the band structure of the smallest clusters numerically using exact diagonalization. The rich phenomenology discussed in this paper can be probed in analog and digital quantum simulators of discrete gauge theories and in Kitaev spin-orbital liquids.

Place, publisher, year, edition, pages
American Physical Society, 2022
National Category
Condensed Matter Physics
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-89146 (URN)10.1103/PhysRevB.105.075132 (DOI)000761168000002 ()2-s2.0-85125178164 (Scopus ID)
Available from: 2022-03-18 Created: 2022-03-18 Last updated: 2023-06-20Bibliographically approved
Marijanovic, F., Moroz, S. & Jeevanesan, B. (2022). Rayleigh waves and cyclotron surface modes of gyroscopic metamaterials. Physical Review B, 106(2), Article ID 024308.
Open this publication in new window or tab >>Rayleigh waves and cyclotron surface modes of gyroscopic metamaterials
2022 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 106, no 2, article id 024308Article in journal (Refereed) Published
Abstract [en]

We investigate the elastic normal modes of two-dimensional media with broken time-reversal and parity symmetries due to a Lorentz term. Our starting point is an elasticity theory that captures the low-energy physics of a diverse range of systems such as gyroscopic metamaterials, skyrmion lattices in thin-film chiral magnets, and certain Wigner crystals. By focusing on a circular disk geometry, we analyze finite-size effects and study the low-frequency shape oscillations of the disk. We demonstrate the emergence of the Rayleigh surface waves from the bottom of the excitation spectrum and investigate how the curvature of the disk-boundary modifies their propagation at long wavelengths. Moreover, we discover a near-cyclotron-frequency wave that is almost completely localized at the boundary of the disk but is distinct from the Rayleigh wave. It can be distinguished from the latter by a characteristic excitation pattern in a small region near the center of the disk.

Place, publisher, year, edition, pages
American Physical Society, 2022
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-91560 (URN)10.1103/PhysRevB.106.024308 (DOI)000832523100001 ()2-s2.0-85135692285 (Scopus ID)
Funder
German Research Foundation (DFG), MO 3013/1-1Swedish Research Council, 2021-03685
Available from: 2022-08-22 Created: 2022-08-22 Last updated: 2023-06-20Bibliographically approved
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